Study on Power Electronic Device Battery Manufacturing At Advance Power Electric Company Limited

By Shawn Das ID: 0921244

An Internship Report Presented In Partial Fulfillment Of Requirements for the Degree Bachelor of Science In Electrical and Electronic Engineering

INDEPENDENT UNIVERSITY, BANGLADESH School of Engineering and Computer Science Department of Electrical and Electronic Engineering

AUTUMN, 2013

Internship

Study on Power Electronic Device Battery Manufacturing At Advance Power Electric Company Limited

By Shawn Das ID: 0921244

has been approved December 2013

---------------------------- Dr. AKM Baki Assistant Professor Department of Electrical and Electronic Engineering School of Engineering and Computer Science

Independent University, Bangladesh

LETTER OF TRANSMITTAL

Mr. A.K.M Baki
Assistant Professor,
School of Engineering and Computer Science,
Independent University, Bangladesh,
Bashundhara,
Dhaka -1212

Dear Sir,

I have the pleasure in submitting you the Internship Report on “Advance Power Electric Company Limited” based on projects carried out within the period of last three months, as part of fulfilling the requirements for Bachelor of Science (B.sc) program at IUB.

This report is based on, “Total manufacturing electronic device which is known as battery at “Advance Power Electric Company Limited”. I have got the opportunity to work in this company under Manufacturing Division for twelve weeks, under the supervision of Engr. Mr. Mahbubul Alam, Managing Director of Advance Power Electric Company. This project gave me both academic and practical exposures. First of all, I have learned about the industrial culture of a prominent Electronic organization of our country. Secondly, the project gave me the opportunity to develop a network with the corporate environment.

I shall be highly obliged if you are kind enough to receive my internship report and provide your valuable judgment. It would be my immense pleasure if you find this report useful and informative to have an apparent perspective on the issue.

Sincerely Yours

-------------------------------
Shawn Das
ID: 0921244
Independent University, Bangladesh. Abstract

This report attempts to give an idea about the two and half months working experience at Advance Power Electric Company Limited (APECL). This report consists of six chapters. First chapter is about the preparatory ideas and the company APECL, the second part is about related theory and practice of battery. This writer has tried to describe the manufacturing process of battery along with related theory and calculation for proper understanding and also the assembling process of various types of battery which is being assembled with different imported components with APECL manufactured housings. In Advance Power Electric Company, the battery designers are giving most of their effort on the formation of grid to make them proper because the weight and thickness of grid are the most important factors to make a proper battery, so that the grid window is fixed. So to arrange the grids into battery, the proper formation of gridding is necessary which the author has tried to describe here briefly. The conclusion and supplementary contents are contained in last chapter with some recommendations. The detailed assembling process along with appropriate diagrams of battery packing system. This writer has tried to give a proper and clear view of two and half month’s practice at Advance Power Electric Company Limited through this report with many visual and textual data gathered from various sources like Internet or APECL data bank along with some diagram of the writer’s own.

ACKNOWLEDGEMENT

The whole praise is to the Almighty GOD, who gave me the opportunity and ability needed to accomplish this work. This Internship report which is entitled as “A STUDY ON POWER ELECTRONIC DEVICE BATTERY MANUFACTURING” is the concrete effort of a number of people. In the process of conducting my practicum report, I would like to express my gratitude and respect to some generous persons for their immense help and enormous cooperation.

First of all I would like to pay my gratitude to Honorable Vice Chancellor Prof. Dr. M. Omar Rahman for giving me such an opportunity to conduct my practicum on this splendid and practical resourceful topic.

Then I would like to pay my gratitude to my respected internship supervisor Dr. AKM Baki, Assistant Professor, Department of EEE, SECS, in INDEPENDENT UNIVERSITY BANGLADESH (IUB). The supervision, support and inspiration that he gave truly helped the progression and smoothness of internship program.

Then I would like to extend my warmest appreciation and thanks to Engr. Mahbubul Alam which is the general manager of company, Md. Aminul Hoque, assistant manager of APECL, Engr. Ashiq, Field Engineer, APECL, Md. Shobuj, Chief Engineer and main technician, APECL and Md. Sharif, Md. Mustafa, Md. Firoz, Md. Karim with all other technicians of APECL for their helping hands to our learning and to make this Internship report named “A Study On Power Electronic Device Battery Manufacturing”.

I am very much grateful to some of our faculties specially Mr. Md. Shoaib Shahriar, Lecturer, SECS,IUB, for his helping hand. I also say my warmest thanks to my advisor Dr. M. Abdur Razzak, Associate Professor, SECS, IUB and member of IEEE. I would like to thank again Dr. Khusru Mohammad Selim, who had taken my major course ‘Solid State Electronics’ (EEE413)

Table Of Content

|Approval | |
|Acknowledgement |iii |
|Abstract |iv |
|List of Figure |viii |
|Chapter: 01 (Introduction) | |
|1.1 Title | |
|1.2 Background | |
|1.3 Precise Objectives | |
|1.4 Methodology | |
|1.5 About Advance Power Electric Company | |
|Chapter: 02 (Battery Theory And Practice) | |
|2.1 Introduction | |
|2.2 General Description of Battery | |
|2.3 History and basic theory of Battery | |
|2.4 Invention of battery | |
|2.5 Different kinds of battery | |
|Chapter: 03 (Design procedure and main parts of battery) | |
|3.1 Flow Chart of the Battery Manufacturing Process | |
|3.2 Battery design procedure | |
|3.3 Main parts of battery | |
|Chapter: 04 (Battery Manufacturing Process And Energy Supply System) | |
|4.1 Introduction | |
|4.2 Manufacturing Process and Construction of Battery | |
|4.3 Supplying System of Energy | |
|Chapter: 05 (Maintenance Battery and Preprocessing of Raw Materials) | |
|5.1 Maintenance of Lead-Acid Battery | |
|5.2 Pre-processing and transfer of Raw Materials | |
|Chapter: 06 (Different Units of Battery Manufacturing Process) | |
|6.1 Breaking Unit | |
|6.2 Rotary Unit | |
|6.3 Grid Casting Unit | |
|6.4 Oxide Unit | |
|6.5 Pasting Unit | |
|6.6 Assembly Unit | |
|Chapter: 07 (Conclusive Part) | |
|7.1 Conclusion | |
|7.2 Recommendation | |
|7.3 References | |
|7.4 Appendix | |

Chapter-1
Introduction

1. Title:

A Study On Power Electronic Device Battery Manufacturing

1.2 Background:

An electric battery is a device consisting of one or more electrochemical cells that convert stored chemical energy into electrical energy. Each battery consists of a negative electrode material, a positive electrode material, an electrolyte that allows ions to move between the electrodes, and terminals that allow current to flow out of the battery to perform work. A device containing an electric cell or a series of electric cells storing energy that can be converted into electrical power (usually in the form of direct current). Common household batteries, such as those used in a flashlight, are usually made of dry cells (the chemicals producing the current are made into a paste). In other batteries, such as car batteries, these chemicals are in liquid form. A Closer Look A battery stores chemical energy, which it converts to electrical energy. A typical battery, such as a car battery, is composed of an arrangement of galvanic cells. Each cell contains two metal electrodes, separate from each other, immersed within an electrolyte containing both positive and negative ions. A chemical reaction between the electrodes and the electrolyte, similar to that found in electroplating, takes place, and the metals dissolve in the electrolyte, leaving electrons behind on the electrodes. However, the metals dissolve at different rates, so a greater number of electrons accumulate at one electrode (creating the negative electrode) than at the other electrode (which becomes the positive electrode). This gives rise to an electric potential between the electrodes, which are typically linked together in series and parallel to one another in order to provide the desired voltage at the battery terminals (12 volts, for example, for a car battery). The buildup of charge on the electrodes prevents the metals from dissolving further, but if the battery is hooked up to an electric circuit through which current may flow, electrons are drawn out of the negative electrodes and into the positive ones, reducing their charge and allowing further chemical reactions. For example: Electrons flow from the zinc casing to the carbon rod, lighting the bulb in the process. The zinc casing acts as a negative electrode; the carbon rod acts as a positive electrode. The ammonium chloride paste acts as the electrolyte and the carbon and the manganese dioxide mixture around the carbon rod extends the battery's life.

2. Precise Object:

1) This work covers the study on assembling and controlling and operation of 12 volt battery.

2) To learn how a order is placed to the manufacturer and assembler by the client depending on loads.

3) To learn about the design criteria’s of batteries of different fields, amount and different kinds of loads.

4) To learn about different manufacturing steps of battery like breaking, melting, gridding, pasting, curing, assembling etc.

5) To learn the testing procedure of battery.

6) Combining the theory with practice with different practical issues applied in the factory.

3. Methodology:

1) First of all, I gathered theoretical knowledge about standard manufacturing process and operation of battery from different books, journals, & internet.

2) Then, I have collected the data about different parameters of batteries.

3) I learned about the battery design procedures from different books.

4) I worked with the engineer and technicians in APECL while they were making a new battery.

5) I was also reported to my supervisor Dr. A.K.M BAKI weekly basis, verified all information of battery manufacturing process and also took different guidelines and objectives to make my work worthy and smooth.

4. About Advance Power Electrical Company:

Since 2002, APECL has continued to carry on the business manufacturing assembling and marketing of all types of batteries to meet the demands of our changing time. They believe that, by successful planning and providing quality products and services it has been impossible to satisfy the various needs of the customer. Hence Advance limited adopted the strategy of developing a major Bangladesh based manufacturing business through acquisitions and other means from a raw materials trader. Advance limited is operated by European latest technologies with around 1000 employee and nationwide distribution networks.

This company, one of the leading industrial concern for all types and sizes of battery manufacturing and marketing organization in Bangladesh. Advance limited has committed to provide quality products to its customers as per international standard and best suited to local environment at affordable price. The motto of the group that focuses the product quality, distribution, branding, customer care and servicing etc. Mahbubul Alam, Managing Director of Advance Power Electric Company is an eminent entrepreneur of the country. He was born in a respectable Muslim family. His honesty, efficiency, punctuality as well as hard working mentality brought him very near with his owner. He never learnt to deceive his employer and such type of human quality made him confident to establish his own business. In early, he started his business named “Advance Power Electric Company” with supply of Coal in different Lead manufacturing industries. Once he found that he has enough ability to produce Lead. Later Mr. Alam started producing heavy duty industrial battery (VOLVO Brand) as well as battery related accessories such as Raw Lead, Lead Oxide, Antimony Lead, Zinc, Plastic Container and so on. In the recent past, APECL is one of the country’s leading electronic technology based enterprise having operations of Battery Manufacturing, Solar Technologies, IPS, Plastic Container Manufacturing. From the very beginning of our Battery Production have the “Air Treatment Plant (ATP)” and “Effluent Treatment Plant (ETP)” which are the best means of prevention of air and water pollution for keeping the environment clean, safe and secured.

Chapter-2
Battery Theory and Practice

1. Introduction:

Prior to the rise of electrical generators and electrical power grids from around the end of the 19th century, batteries were the main source of electricity. Successive improvements in battery technology permitted the rise of major electrical advances, from early scientific studies to the rise of telegraphs and telephones, leading eventually to portable computers, mobile phones, electric cars and multitudes of other electrical devices. A battery is a collection of multiple electrochemical cells, but in popular usage battery often refers to a single cell. The first electrochemical cell was developed by the Italian physicist Alessandro Volta in 1792, and in 1800 he invented the first battery, a “pile" of many cells in series. The usage of "battery" to describe electrical devices dates to Benjamin Franklin who in1748 described multiple Leyden Jars by analogy to a battery of canons. Volta believed the current was the result of two different materials simply touching each other—an obsolete scientific theory known as contact tension—and not the result of chemical reactions. As a consequence, he regarded the corrosion of the zinc plates as an unrelated flaw that could perhaps be fixed by changing the materials somehow.

However, no scientist ever succeeded in preventing this corrosion. In fact, it was observed that the corrosion was faster when a higher current was drawn. This suggested that the corrosion was actually integral to the battery's ability to produce a current. This, in part, led to the rejection of Volta's contact tension theory in favor of electrochemical theory.

2. General Description of Battery:

A battery is a device that stores energy while it is being charged and releases energy while it is being discharged. The major responsibility of battery is to supply current to stand the engine. To, supplement the vehicle load requirements whenever they exceed the charging systems ability to deliver to act as a voltage stabilizer in the charging system. There are a lot of different battery technologies, but lead acid batteries, which consist of plates of lead dioxide and spongy lead, immersed in a sulphuric acid solution contained in a durable housing, are most appropriate for use with inverters and mobile power solutions. Lead acid battery technology has come a long way since 1859, the year it was invented. You no longer have to check the state of charge with a hygrometer, or top the batteries up with distilled water. Batteries are now safer, more reliable and in some cases, virtually maintenance free. Lead acid batteries are recommended for use inverters/UPS because: They are low cost, widely available and easy to manufacture. They are durable and dependable when properly used and stored. The self-discharge rate is lower than that of other battery technologies. They can produce a lot of current very fast, which is important in inverter applications.

3. History and Basic of Battery:

In strict terms, a battery is a collection of multiple electrochemical cells, but in popular usage battery often refers to a single cell. The first electrochemical cell was developed by the Italian physicist Alessandro Volta in 1792, and in 1800 he invented the first battery, a “pile" of many cells in series. The usage of "battery" to describe electrical devices dates to Benjamin Franklin who in1748 described multiple Leyden Jars by analogy to a battery of canons. Thus Franklin’s usage to describe multiple Leyden jars predated Volta's use of multiple galvanic cells. It is speculated, but not established, that several ancient artifacts consisting of copper sheets and iron bars, and known as Baghdad Batteries may have been galvanic cells. Volta’s work was stimulated by the Italian anatomist and physiologist Luigi Galvani, who in 1780 noticed that dissected frog's legs, would twitch when struck by a spark from a Leyden Jar, an external source of electricity. In 1786 he noticed that twitching would occur during lightning storms. After many years Galvani learned how to produce twitching without using any external source of electricity. In 1791, he published a report on "animal electricity." He created an electric circuit consisting of the frog's leg (FL) and two different metals A and B, each metal touching the frog's leg and each other, thus producing the circuit A–FL–B–A–FL–B...etc. In modern terms, the frog's leg served as both the electrolyte and the sensor and the metals served as electrodes. He noticed that even though the frog was dead, its legs would twitch when he touched them with the metals. Within a year, Volta realized the frog's moist tissues could be replaced by cardboard soaked in salt water, and the frog's muscular response could be replaced by another form of electrical detection. He already had studied the electrostatic phenomenon of capacitance, which required measurements of electric charge and of electrical potential("tension"). Building on this experience, Volta was able to detect electric current through his system, also called a Galvanic cell. The terminal voltage of a cell that is not discharging is called its electromotive(emf) and has the same unit as electrical potential, named (voltage) and measured in volts, in honor of Volta. In 1800, Volta invented the battery by placing many voltaic cells in series, piling them one above the other. This voltaic pile gave a greatly enhanced net emf for the combination with a 3 voltage of about 50 volts for a 32-cell pile. In many parts of Europe batteries continue to be called piles. Volta did not appreciate that the voltage was due to chemical reactions. He thought that his cells were an inexhaustible source of energy and that the associated corrosion effect sat the electrodes were a mere nuisance, rather than an unavoidable consequence of their operation, as Michel Faraday showed in 1834. According to Faraday, cat ions (positively charged ions) are attracted to the cathode and anions (negatively charged ions) are attracted to the anode. Although early batteries were of great value for experimental purposes, in practice their voltages fluctuated and they could not provide a large current for a sustained period. Later, starting with the Daniel cell in 1836, batteries provided more reliable currents and were adopted by industry for use in stationary devices, in particular in telegraph networks where they were the only practical source of electricity, since electrical distribution networks did not exist at the time. These wet cells used liquid electrolytes, which were prone to leakage and spillage if not handled correctly. Many used glass jars to hold their components, which made them fragile. These characteristics made wet cells unsuitable for portable appliances. Near the end of the nineteenth century, the invention of dry cell batteries, which replaced the liquid electrolyte with a paste, made portable electrical devices practical. Since then, batteries have gained popularity as they became portable and useful for a variety of purposes.

4. Invention of Battery:

The trough battery, which was in essence a Voltaic Pile, lay down to prevent electrolyte leakage. In 1780, Luigi Galvani was dissecting a frog affixed to a brass hook. When he touched its leg with his iron scalpel, the leg twitched. Galvani believed the energy that drove this contraction came from the leg itself, and called it "animal electricity". However, Alessandro Volta, a friend and fellow scientist, disagreed, believing this phenomenon was caused by two different metals joined together by a moist intermediary. He verified this hypothesis through experiment, and published the results in 1791. In 1800, Volta invented the first true battery, which came to be known as the voltaic pile. The voltaic pile consisted of pairs of copper and zinc discs piled on top of each other, separated by a layer of cloth or cardboard soaked in brine.

Unlike the Leyden jar, the voltaic pile produced a continuous and stable current, and lost little charge over time when not in use, though his early models could not produce a voltage strong enough to produce sparks. He experimented with various metals and found that zinc and silver gave the best results. Volta believed the current was the result of two different materials simply touching each other—an obsolete scientific theory known as contact tension—and not the result of chemical reactions. As a consequence, he regarded the corrosion of the zinc plates as an unrelated flaw that could perhaps be fixed by changing the materials somehow.

However, no scientist ever succeeded in preventing this corrosion. In fact, it was observed that the corrosion was faster when a higher current was drawn. This suggested that the corrosion was actually integral to the battery's ability to produce a current. This, in part, led to the rejection of Volta's contact tension theory in favor of electrochemical theory. Volta's illustrations of his Crown of Cups and voltaic pile have extra metal disks, now known to be unnecessary, on both the top and bottom.

The figure associated with this section, of the zinc-copper voltaic pile, has the modern design; an indication that “contacts tension" is not the source of electromotive force for the voltaic pile. Volta’s original pile models had some technical flaws, one of them involving the electrolyte leaking and causing short-circuits due to the weight of the discs compressing the brine-soaked cloth. An Englishman named William Cruickshank solved this problem by laying the elements in a box instead of piling them in a stack. This was known as the trough battery. Volta himself invented a variant that consisted of a chain of cups filled with a salt solution, linked together by metallic arcs dipped into the liquid. This was known as the Crown of Cups. These arcs were made of two different metals (zinc and copper) soldered together. This model also proved to be more efficient than his original piles, though it did not prove as popular.

[pic][pic]

Figure 01: A zinc-copper voltaic pile

Another problem with Volta's batteries was short battery life (an hour's worth at best) which was caused by two phenomena. The first was that the current produced electrolyzed the electrolyte solution, resulting in a film of hydrogen bubbles forming on the copper, which steadily increased the internal resistance of the battery (This effect, called polarization, is counteracted in modern cells by additional measures). The other was a phenomenon called local action, where in minute short-circuits would form around impurities in the zinc, causing the zinc to degrade.

The latter problem was solved in 1835 by William Sturgeon, who found that amalgamated zinc, whose surface had been treated with some mercury, didn't suffer from local action. Despite its flaws, Volta's batteries provided a steadier current than Leyden jars, and made possible many new experiments and discoveries, such as the first electrolysis of water by Anthony Carlisle and William Nicholson.

5. Different Kind of Battery:

[pic]
Figure 02: Rechargeable batteries and dry cells Lead-acid
19th-century illustration of Planet’s original lead-acid cell

Lead Acid Battery : Up to this point, all existing batteries would be permanently drained when all their chemical reactions were spent. In 1859, Gaston Planet invented the lead-acid battery, the first-ever battery that could be recharged by passing a reverse current through it. A lead acid cell consists of a lead anode and a lead dioxide cathode immersed in sulphuric acid. Both electrodes react with the acid to produce lead sulfate, but the reaction at the lead anode releases electrons whilst the reaction at the lead dioxide consumes them, thus producing a current. These chemical reactions can be reversed by passing a reverse current through the battery, thereby recharging it.

Planet’s first model consisted of two lead sheets separated by rubber strips and rolled into a spiral. His batteries were first used to power the lights in train carriages while stopped at a station. In 1881, Camille Alphonse Faure invented an improved version that consisted of a lead grid lattice into which a lead oxide paste was pressed, forming a plate. Multiple plates could be stacked for greater performance. This design was easier to mass-produce. Compared to other batteries, Planet’s was rather heavy and bulky for the amount of energy it could hold. However, it could produce remarkably large currents in surges. It also had very low internal resistance, meaning that a single battery could be used to power multiple circuits. The lead-acid battery is still used today in automobiles and other applications where weight is not a big factor. The basic principle has not changed since 1859, though in the 1970s a variant was developed that used a gel electrolyte instead of a liquid (commonly known as a "gel cell"), allowing the battery to be used in different positions without failure or leakage. Today cells are classified as "primary" if they produce a current only until their chemical reactants are exhausted, and "secondary" if the chemical reactions can be reversed by recharging the cell. The lead-acid cell was the first "secondary" cell. General chemistry textbooks provide detailed information about lead storage (also known as lead acid) batteries, and should be consulted in preparation for this experiment.
Most textbook discussions about lead storage batteries omit information about the process known as the “initial charging” of the battery. This is the process by which the lead storage battery is prepared for discharge, followed by recharging, processes which are discussed in detail in most texts. The “initial charging” process is simply the electrolysis involving two lead strips immersed in sulfuric acid. The strips are connected to an external power supply which pumps electrons from one strip to the other, forcing oxidation reactions to occur at the anode, and reduction reactions to occur at the cathode. Textbooks provide guidance about determining which of the possible redox reactions will likely occur at the anode and cathode during electrolysis. For the case of the lead storage battery undergoing “initial charging,” the candidate materials for oxidation include Pb(s) and H2O, while candidate materials for reduction include H2O and H+(aq). Standard reduction potential tables include reactions involving these materials, from which it is possible to select the likely anode and cathode reactions during electrolysis.
Lithium and lithium-ion batteries
Lithium is the metal with lowest density and with the greatest electrochemical potential and energy-to-weight ratio, so in theory it would be an ideal material with which to make batteries. Experimentation with lithium batteries began in 1912 under G.N. Lewis, and in the 1970s the first lithium batteries were sold.

Three important developments marked the 1980s. In 1980 an American chemist John B. Good enough disclosed the positive lead and a French research scientist Rachid Yazami discovered the graphite anode (negative lead). This led a research team managed by Akira Yoshino of Asahi Chemical, Japan to build the first lithium ion battery prototype in 1985, a rechargeable and more stable version of the lithium battery; followed by Sony that commercialized the lithium ion battery in 1991.
In 1997, the lithium ion polymer battery was released. These batteries hold their electrolyte in a solid polymer composite instead of a liquid solvent, and the electrodes and separators are laminated to each other. The latter difference allows the battery to be encased in a flexible wrapping instead of a rigid metal casing, which means such batteries can be specifically shaped to fit a particular device. They also have a higher energy density than normal lithium ion batteries. These advantages have made it a choice battery for portable electronics such as mobile phones and personal digital assistants, as they allow for more flexible and compact design.

Nickel Cadmium (NI-CD) Batteries
Ni-Cd batteries have been around nearly as long as lead-acid. Commercial products have been available since around 19007. Pocket plate designs are typically used for long to high current types, while fiber plates are used for extremely high current short demand applications like engine starting.

While Ni-Cd batteries typically cost many times what a comparable lead-acid does, their characteristics make them ideal for many applications. Their advantages over lead-acid designs include:

➢ High resistance to damage by over charging ➢ Very small loss in capacity at low temperatures ➢ Much greater resistance to loss of life when operated at high temperatures ➢ No dip in voltage during the first minute of discharge ➢ Stainless Steel interconnecting hardware does not loose compression or corrode ➢ Lower water consumption ➢ Lower maintenance cost ➢ No rapid decrease in capacity after reaching a certain point in battery life

Chapter-3

Design procedure and main parts of battery

1. Flow Chart of the Battery Manufacturing process:

[pic]

2. Battery Design Procedure:

FLAT PLATE VERSUS TUBULAR

There are two basic types of industrial forklift truck batteries available to the user today; the flat pasted plate heavy duty type as manufactured by Bulldog Battery Corporation and the majority of battery manufacturers and the “tubular” type produced by a few companies. These different battery types get their name from the design of the positive plate. In general, the negative plates are identical in both types. The essential difference is that in the flat plate design, the positive plate is a rugged lead alloy grid which is filled with a specially compounded paste active material whereas in the “tubular” design the positive plate is composed of a series of parallel tubes filled with lead oxide. To understand the differences in the performance of the two types, it is helpful to know how the two positive plate designs are produced since different manufacturing methods are used which have a major influence on the way the batteries perform in service.

THE FLAT PASTED PLATE

The manufacturing process begins with a rugged cast grid usually made from a lead alloy containing from 3-6% antimony. The grids are pasted on an automatic machine with a specially compounded mixture of lead oxide (finely divided lead) water and sulfuric acid. Following the pasting operation, the plates are “cured” by a process that converts the active material in the plate to the desired composition and which causes the paste to set to hard cement- like mass. Plates made this way are extremely rugged and will “ring like a bell” when struck. The plates and cells made in this process are very consistent and have the following characteristics:

1. Good electrical performance
2. Long cycle life
3. Tough and durable
4. Good reserve of pasted material for long life
5. Good reserve of lead for long life
6. With their glass wrap the plate is well protected against life limiting shedding.

3. Main Parts of Battery:

All batteries contain one or more cells but people often use the terms battery and cell interchangeably. A cell is just the working chemical unit inside a battery; one battery can contain any number of cells. A cell has three main parts: a positive electrode (terminal), negative electrode, and a liquid or solid separating them called the electrolyte.

When a battery is connected to an electric circuit, a chemical reaction takes place in the electrolyte causing ions to flow through it one way, with electrons flowing through the outer circuit in the other direction. This movement of electric charge makes an electric current flow through the cell and through the circuit it is connected to. That's the theory anyway. Now let's look at it in practice.

Common Terms of Battery:

AMPERE: The unit of measure of current flow through a conductor of a circuit.

AMPERE HOUR: A unit of measure for battery capacity obtained by multiplying the current flow in ampere by the time in hours of discharge.

CIRCUIT: The path of an Electric Current.

SERIES CIRCUIT: A circuit which has only one path for the current to flow. In battery, connection between negative of first to the positive of second is called series connection. Series connection increases battery voltage keeping. Ampere Hour unchanged.

PARALLEL CIRCUIT: A circuit which provides more than one path for current flow. Here positive of one battery is connected to the positive of another battery. This arrangement increases. All keeping voltage unchanged.

CURRENT: The rate of flow of electricity. The movement of electrons along a conductor.

ALTERNATING CURRENT (AC): A current that varies periodically in magnitude and direction. Type of electrical current available in our homes.

DIRECT CURRENT (DC): Current flowing in one direction at all times, from positive to Negative. All batteries supply DC current.

CYCLE: In a battery a discharge and a recharge is a cycle.

DISCHARGING: When a battery is delivering power, it is said to be discharging.

VOTAGE DROP: The net difference in electrical pressure (voltage). When measured across a resistance or impedance.

OHM: A unit for measuring electrical resistance which opposes current flow and causes heat when current flows.

OPEN CIRCUIT VOLTAGE: Voltage between positive & negative post of a battery. When it is not delivering or receiving power. It is 2.1 volt per cell for a fully changed lead acid battery.

RESERVE CAPACITY RATING: The time in minutes that a battery can deliver 25 amperes. This rating represents the time the battery will continue to operate essential accessories during right driving if the alternator or generator fails.

RESISTANCE: The opposition offered by a conductor to the free flow of an electric current.

SHORT CIRCUIT: A shortening of electrical path. Usually within a battery at a given time. The state of charge is determined by measuring specific gravity or the stabilized open circuit voltage.

VOLT: The unit of measure of Electrical pressure.

WATT: The unit of measuring electrical energy or “Work” Formula : Watt + Ampere × Volt.

CHARGE: The quantity of electricity putting into a cell during charging. It is measured in AH.

CHARGING RATE: Current in ampere which a cell or battery delivers through an external circuit.

DISCHARGE RATE: Current in ampere which a cell or battery delivers through an external circuit.

HOUR RATE: The discharge rate at which a cell or battery shall be discharged to a specified end voltage in a given time

ELECTROLYTE: Mixture of concentrated sulphuic acid and de-ionized water. It is a supplier of hydrogen and sulphate ions for the reaction:PbO2+Pb+2H2SO4= 2PbSO4+2H2O.

ELEMENT: A set of positive and negative plates assembled with separators.

AMP-HOUR CAPACITY: The quantity of Electricity in ampere Hour which may be drawn from a cell or a battery at a specified rate of discharge during a specified period of hours.

RATED CAPACITY: Amp-Hour Capacity of a cell or battery assigned to it by the manufacture.

SALF DISCHARGE: Loss of charge due to internal reactions in the cell, the cell being on open or closed-circuit.

END VOLTAGE: The closed circuit voltage of a cell or a battery across its terminals when current is flowing.

HEIGHT OF BATTERY: Vertical dimension form the bottom of the container to the top of the terminal posts, or vent plugs or container handle, whatever is the highest.

HEIGHT OF CONTAINER: Vertical dimension form the bottom to the top of the container.

BATTERY EFECIENCY: The ratio of the output to the input in terms of electrical power.

PRIMARY CELL: Primary cell is one which cannot be recharging a dry cell battery.

SECONDARY CELL: A voltage cell which is approximately reversible & which discharge can be brought back to its initial (charged) chemical condition by passing a unidirectional current through it is direction reverse to that of discharge current. Also known a storage cell. It is office called accumulator or storage cell.

Chapter-4

Battery Manufacturing Process and Energy Supply System

1. Introduction:

Batteries have been a part of our lifestyle for so long that many of us tend to take them for granted. Batteries are expected to perform reliably and trouble-free with little or no attention. In plant environments where large quantities of materials must be moved, lack of proper attention can result in reduced battery life, inefficient materials handling, damage to lift-truck equipment, and a poor return on capital investment. Because they play such a vital role in materials handling in most segments of industry, batteries should receive a great deal of attention in any plant program of care and preventative maintenance. Ideally, batteries should be handled by trained and skilled personnel—not only because of the financial investment, but also due to the inherent dangers involved with battery handling and maintenance. The purpose of this manual is to assist those responsible for this care and maintenance in obtaining the most efficient service from their batteries using procedures which provide the safest possible environment. Industrial batteries manufactured today are usually warranted to deliver a total of 1500 cycles. A cycle is normally considered to be one discharge and one recharge. At a frequency of one cycle per day, a five years life expected. Many factors can alter the life achieved by the user. With adequate care and preventative maintenance 2100 cycles are entirely within reason. It is thought by veteran battery service personal that if users would focus on four areas, normal battery life would greatly increase and as much as 70 percent of battery repair costs experienced today would not be required. These areas are as follows:

✓ Proper watering ✓ Regular cleaning and neutralizing ✓ Maintaining batteries at a proper temperature ✓ Discharging to as near 80 percent of capacity as possible prior to recharging

2. Manufacturing process and construction of battery:

Lead acid storage batteries are produced from lead alloy ingots and lead oxide. The lead oxide may be prepared by the battery manufacturer, as is the case for many larger battery manufacturing facilities, or may be purchased from a supplier. Battery grids are manufactured by either casting or stamping operations. In the casting operation, lead alloy ingots are charged to a melting pot, from which the molten lead flows into molds that form the battery grids. The stamping operation involves cutting or stamping the battery grids from lead sheets. The grids are often cast or stamped in doublets and split apart (slitting) after they have been either flash dried or cured. The pastes used to fill the battery grids are made in batch-type processes. A mixture of lead oxide powder, water, and sulfuric acid produces a positive paste, and the same ingredients in slightly different proportions with the addition of an expander (generally a mixture of barium sulfate, carbon black, and organics), make the negative paste. Pasting machines then force these pastes into the interstices of the grids, which are made into plates. At the completion of this process, a chemical reaction starts in the paste and the mass gradually hardens, liberating heat. As the setting process continues, needle-shaped crystals of lead sulfate (PbSO4) form throughout the mass. To provide optimum conditions for the setting process, the plates are kept at a relative humidity near 90 percent and a temperature near 32°C (90°F) for about 48 hours and are then allowed to dry under ambient conditions. After the plates are cured they are sent to the 3-process operation of plate stacking, plate burning, and element assembly in the battery case. In this process the doublet plates are first cut apart and depending upon whether they are dry-charged or to be wet-formed, are stacked in an alternating positive and negative block formation, with insulators between them. These insulators are made of materials such as non-conductive plastic, or glass fiber. Leads are then welded to tabs on each positive or negative plate or in an element during the burning operation is the cast-on connection, and positive and negative tabs are then independently welded to produce an element. The elements are automatically placed into a battery case. A top is placed on the battery case. The posts on the case top then are welded to 2 individual points that connect the positive and negative plates to the positive and negative posts, respectively. During dry-charge formation, the battery plates are immersed in a dilute sulfuric acid solution, the positive plates are connected to the positive pole of a direct current (DC) source and the negative plates connected to the negative pole of the DC source. In the wet formation process, this is done with the plates in the battery case. After forming, the acid may be dumped and fresh acid is added, and a boost charge is applied to complete the battery. In dry formation, the individual plates may be assembled into elements first and then formed in tanks or formed as individual plates. In this case of formed elements, the elements are then placed in the battery cases, the positive and negative parts of the elements are connected to the positive and negative terminals of the battery, and the batteries are shipped dry. Defective parts are either reclaimed at the battery plant or are sent to a secondary lead smelter. Lead reclamation facilities at battery plants are generally small pot furnaces for non-oxidized lead. Approximately 1 to 4 percent of the lead processed at a typical lead acid battery plant is recycled through the reclamation operation as paste or metal. In recent years, however, the general trend in the lead-acid battery manufacturing industry has been to send metals to secondary lead smelters for reclamation.

First practical battery
Daniel cell
[pic]

Figure 03: Schematic representation of Daniel’s original cell

A British chemist named John Frederic Daniel searched for a way to eliminate the hydrogen bubble problem found in the Voltaic Pile, and his solution was to use a second electrolyte to consume the hydrogen produced by the first. In 1836 he invented the Daniel cell, which consisted of a copper pot filled with a copper sulfate solution, in which was immersed an unglazed earthenware container filled with sulfuric acid and a zinc electrode. He was searching for a way to eliminate the hydrogen bubble problem found in the voltaic pile, and his solution was to use a second electrolyte to consume the hydrogen produced by the first.

The earthenware barrier was porous, which allowed ions to pass through but kept the solutions from mixing. Without this barrier, when no current was drawn the copper ions would drift to the zinc anode and undergo reduction without producing a current, which would destroy the battery's life.

Over time, copper buildup would block the pores in the earthenware barrier and cut short the battery's life. Nevertheless, the Daniel cell was a great improvement over the existing technology used in the early days of battery development and was the first practical source of electricity. It provided a longer and more reliable current than the Voltaic cell because the electrolyte deposited copper (a conductor) rather than hydrogen (an insulator) on the cathode. It was also safer and less corrosive. It had an operating voltage of roughly 1.1 volts. It soon became the industry standard for use, especially with the new telegraph networks.

The Daniel cell is also the historical basis for the contemporary definition of the volt, which is the unit of electromotive force in the International System of Units. The definitions of electrical units that were proposed at the 1881 International Conference of Electricians were designed so that the electromotive force of the Daniel cell would be about 1.0 volts. With contemporary definitions, the standard potential of the Daniel cell is actually 1.10 V.

Battery construction

The main components are:

1. Plate Grid – The grid are the supporting framework for the active materials plates. They conduct the current to & from the active of the plates. They are made to an alloy lead.

2. Paste – Pastes are prepared from lead oxides water & sulphuric acid.

3. Positive plates – They are made by pasting paste on to the grids prepared with lead oxide, sulphuric acid, water & others activities & fibers but no expanders are used in positive plates. After the plates have been paste have been pasted & dried the positive plate have a light brown color.

4. Negative plates - They are made by pasting paste as like as positive plates. The only difference is the expander used in the paste.

5. Separator – If a positive plate touches a negative plate a short CKT results & all the plate in the cell lose their stored energy. Therefore the plates are kept apart by separators. A separator is a thin sheet of electrically insulating finely porous material which permits the passage of charged ions of the electrolyte between the positive & negative plates.

6. Container –The outside case or shell of the battery of the battery is a one piece rectangular shaped container with the appropriate number of cells molded to polypropylene hard rubber or other plastic like materials. It is designed to – Withstand the temperature extremes of cold & heat. Resist damage by mechanical shock in rough road service. Resist acid absorption.

7. Cell cover - The cell covers are usually made of plastic materials.

8. Vent plugs- vent plugs are baffled so gas can escape from the cell.

9. Cell connectors- The cells of a battery are connected in series & the battery voltage will equal the sum of the cell voltage.

10. Cover to container seal – Acid cannot be permitted to leak between the cover & the container to the outside surface of the battery.

3. Supplying system of Energy:

A lead-acid motive power battery is a portable energy source for supplying direct (DC) electrical current to electric vehicles. It consists of two or more cells connected in a series and assembled into a metal or fiberglass tray or container. This type of battery comes in a wide variety of shapes, voltages, and ampere-hour (AH) capacities. Each cell of a battery contains a group of positive and negative plates, interleaved so that positives and negatives alternate. The negative plates outnumber the positives by one. The positive plate consists of active material (lead dioxide) retained within the positive grid lattice. The material is held firmly against the grid with a retention system incorporating a fiberglass mat, strain mat, Koroseal retainer, and a plastic boot. This assembly is then enclosed in a polyethylene envelope which provides insulation and edge protection. The negative active material (sponge lead) is maintained within the thinner negative grid. No retention system is used on the negative plate as there is only slight shedding of the active material throughout its normal service life. The positive and negative plates are insulated from each other by the polyethylene sleeve separator surrounding the positive plate assembly. All positive plates in each cell are paralleled by connection to the positive strap. All the negative plates in each cell are paralleled by connection to the negative strap. The plates and insulating materials are later submerged in a solution of sulfuric acid and water, called electrolyte, and housed in an acid-proof polypropylene container called a jar. Polypropylene covers with holes through which the positive and negative posts protrude are then welded to the jar. A removable vent cap allows access into the cell through the cover for the purpose of water addition and cell inspection via hydrometer readings. Each cell has a nominal voltage of two volts, thus, a 6-cell battery is referred to as a 12-volt battery, and an 18-cell battery as a 36-volt battery, etc. Increasing or decreasing the number of plates or the physical size of the cell has no effect on the battery voltage, but does affect the AH capacity. Nominal battery voltage is affected by increasing or decreasing the number of cells in the series circuit. A battery is a device which stores energy in a chemical form and releases that energy on demand in an electrical form to an external load, such as a motor. The battery releases power by the reaction of the electrolyte with the active material of positive and negative plates (electrodes). In a fully charged battery, the positive active material is lead dioxide (PbO2); the negative active material is sponge lead (Pb); and the electrolyte, which has a specific gravity of 1.280 or above, is a solution of sulfuric acid (H2SO4) and water. The open circuit voltage of each cell is 2.12 volts.

The Discharging Battery

When a battery is connected to an electrical load, the stored energy is released in the form of DC
Electrical energy. During the process of energy conversion, the internal components of the battery cells undergo a chemical change. The sulfuric acid (H2SO4) combines with the lead peroxide (PbO2) of the positive plates and with the sponge lead (Pb) of the negative plates and transforms them both to lead sulfate (PbSO4). The reversible reaction may be shown as follows:

PbO2 Pb 2H2SO4 2PbSO4 2H2O

Lead Sponge Sulfuric Lead Water
Peroxide lead Acid DISCHARGE Sulfate

The Charging Battery

The chemical energy in the battery is restored by charging the battery, thereby reversing the discharge reaction. During the charge and especially toward the end of it, hydrogen and oxygen gas are produced by the electrolytic background of water on the plate surfaces.

Chemically the reaction is:

2H2O 2H2 O2
Water
ELECTRICITY Hydrogen Oxygen Gas Gas

Chapter-5

Maintenance Battery and Preprocessing of Raw Materials

1. Maintenance of Lead-Acid Battery:

Battery subsystems for photovoltaic installations in remote locations must require low maintenance. The cost of maintenance can be prohibitive for remote systems in isolated areas where service personnel can visit the installation no more than once or twice a year. Attended systems may have trained personnel available to perform maintenance. Battery designs with greater wet and cycle life, but which may also require greater maintenance, may be selected for these applications. A key step to long life is to properly train service personnel using service and operating instructions provided by the battery and photovoltaic system manufacturers. Maintenance will normally consist of equalization charges, watering of battery cells, checks on individual cell voltage and specific gravity and cleaning the tops of cells of dust, dirt, acid spillage and spray.

Pre-processing and transfer of Raw Materials

Applied processes and techniques Ores, concentrates and secondary raw materials are sometimes in a form that cannot be used directly in the main process. Drying/thawing may be needed for control or safety reasons. The material size may need to be increased or decreased to promote reactions or reduce oxidation. Reducing agents such as coal or coke and fluxes or other slag forming materials may need to be added to control the metallurgical process. Coatings may need to be removed to avoid process abatement problems and improve melting rates. All of these techniques are used to produce a more controllable and reliable feed for the main process and are also used in precious metal recovery to assay the raw material so that toll recovery charges can be calculated.

Thawing is performed to allow frozen material to be handled. This occurs for instance when ores or concentrates or fossil solid fuels such as coal are discharged from a train or ship in the wintertime. Thawing can be achieved by using steam jets in order to just melt the ice and to be able to unload the raw material.

Drying processes are used to produce a raw material that is suitable for the main production process. The presence of water is often avoided for several reasons.

• It is dangerous when large volumes of steam are produced rapidly in a very hot furnace.
• Water can produce variable heat demand in a concentrate burner, which upsets the process control and can inhibit auto-thermal operation.
• Separate drying at low temperatures reduces the energy requirements. This is due to the energy required to super heat the steam within a smelter and the significant increase in the overall gas volume, which increases the fan duty.
• Corrosion effects.
• Water vapor may react with carbon to form H2 and CO.

Drying is usually achieved by the application of direct heat from a burner or by steam jets, or indirectly using steam or hot air in heat exchanger coils. The heat generated from pyro metallurgical processes is also often used for this purpose as well as the CO rich off-gas that can be burned to dry the raw material. Rotary kilns and fluidized bed dryers are used. The dried material is usually very dusty and extraction and abatement systems are used to collect dusty gases. Collected dusts are returned to the process. Dried ores and concentrates can also be pyrophoric and the design of the abatement system usually takes this into account, nitrogen blanketing or the low residual oxygen in combustion gases can be used to suppress ignition.

Chapter-6
Different Units of Battery Manufacturing Process

1. Breaking Unit:

Battery-Breaking Processes

The most common battery used today has been in commercial use for over 130 years. First demonstrated by Gaston Planet in 1860, the venerable lead-acid battery is still the mainstay of energy storage. Over the years there have been many evolutions in the technology, but the basic chemistry has not changed. Lead-acid battery physical plate designs have changed from solid lead to include Munched, pasted and tubular plate designs. Separator technology has gone from wood to natural rubber, synthetic rubber and fiberglass and other synthetic fibers. Plate chemistry has changed from pure lead, to include lead-antimony, lead-calcium, lead-selenium (and its relatives) and lead-tin. The old open tank and glass battery jars have been replaced by vented cells in various plastic containers and valve-regulated designs.

In the 1970s, most battery breakers used saws for decaying. In this process, the top is severed, the acid is drained, and the plates are dumped from the case. The lead posts are recovered from the tops by crushing and separation. This process is still utilized by many lead smellers in the United States and throughout the world. In the late 1970s and early 1980s, several mechanical processes were developed to break the batteries. Technologies were developed to crush the whole batteries, separate the case from the lead-bearing materials, separate the hard rubber (ebonite) and separators from the plastic cases, and, in some cases, separate the paste portion of the battery from the metallic. The acid is neutralized in a separate procedure.

[pic]

A recent innovation desulfurizes the paste, produces lead carbonate, recovers sodium sulfate crystals, and recycles the H2O.Virtually all battery-wrecking processes now recycle the polypropylene battery cases. Battery breakers process from 5000 to more than 50000 spent automobile batteries per day. Mainly Battery breaking is used to recover lead, nickel, cadmium and other materials from batteries. For lead-acid batteries, hammer mills are used to break the battery cases to liberate lead (as grids) and lead compounds (as paste) and allow the recovery of the plastic case material (mainly poly-propylene), the electrolyte is also removed and treated or used. Two-stage crushing can be used to control the particle size and prevent the lead oxide from being impacted into the plastic during a single stage mill. Plastic material is separated and washed to improve the quality and produce plastic that is suitable for recycling. The acid content of the batteries can contaminate land and water if it is not collected and handled properly, sealed acid resistant drainage systems can be used with dedicated collection and storage tanks. The milling stages can produce an acid mist; this can be collected in wet scrubbers or mist filters. Ni/Cd batteries are pyrolised to remove any plastic coating and to open the batteries. Pyrolysis is carried out at low temperatures and the gases are treated in an afterburner and then a bag filter. Cadmium and nickel are recovered from the electrodes and steel from the casing material.

2. Rotary Unit:

The section of the factory is rotary section. First of all, the factory labors collect all the dross and small parts from the batteries. Rotary furnace is a refractory lined rotating cylinder fitted with burner at one end. A charging door is provided at one end and the burner can sometimes be housed in this.

Oxy-fuel firing can be used. The furnaces can be either “long” or “short” and several variants exist.
• Short rotary furnaces: Smelting of secondary lead, precious metals etc.
• Long rotary furnaces: Melting and recovery of aluminum scrap etc.
• Thomas furnace: Melting and refining copper scrap etc.
• Rotary furnace with submerged tubers: Refining of blister or black copper, slag cleaning etc.

Furnace rotation can be varied to give a complete reaction of the charged material and high efficiency. Raw materials are usually charged via an end door, this is usually enclosed and extracted to prevent fume emissions. The furnaces use oil or gas fuel and oxy-burners are commonly used, heat from the burner is transferred to the refractory wall and the charge is heated by the refractory during rotation.

Slags and metal produced during the process can be tapped from a tapping hole at the door end or at the mid-point of the furnace. The tapping hole is orientated by partial rotation of the furnace to maintain the separation of the metal and slag. Tapping from the door end allows fume to be collected from a single enclosure and extraction system. Tilting rotary furnaces are also used, they show improved recovery rates for some feed stocks and can have less reliance on fluxes.

A variety of metals can be smelted or melted in these furnaces the furnace is used for smelting, converting and slag treatment. It is used to produce primary and secondary copper and lead, Ferro-nickel and for the recovery of precious metals. In this factory, the workers put all small parts and dross into the furnace and melt them at 900-1000 Degree Celsius. Furnaces are used for a variety of purposes in this industry such as roasting or claiming raw materials, melting and refining metals and for smelting ores and concentrates.

After sometimes, we can get lead which is normally liquid and its factory name normal lead. This time, these normal lead is melted by 450 degree Celsius with different kinds of chemicals such as soda, carbon etc. At least, 16 types of chemicals are mixed with the lead. Finally, we get the antimony and pure leads. Two types of leads can get from the normal lead. Then, the antimony lead can go to the casting section which is called grid casting unit and rest of the pure lead is used to the oxide unit.

3. Grid Casting Unit:

Grid casting processes

Normally, molten metal from the furnace or holding section can be cast continuously or in batches. Continuous casting uses either vertical or horizontal modes but discontinuous casting normally uses the vertical mode. Up cast techniques are also used. Billets and cakes/slabs are produced and are processed further. In the case of the production of billets, slabs or cakes, metal is melted and passes via a holding furnace into a vertical or horizontal billet caster. Sections of billets are sawn off for further fabrication. Special processes are applied for specific products from copper and copper alloys: Up cast process for wires and tubes, horizontal continuous casting for strip and sections, vertical strip casting and roll process for fabrication of copper tubes.

Copper cathode and copper and alloy scrap is used as the raw material and is normally stored in open bays so that the different alloys can be blended to produce the final alloy. This pre blending is an important factor to reduce the time taken in preparing the melt, which minimizes the energy used and reduces the reliance on expensive Master Alloys. With induction furnaces scrap is cut into small sizes to improve melting efficiency and allow easy deployment of hoods etc. Raw materials are also brasses or copper turnings and borings and in this case are coated with lubricants. Care is taken to prevent oil leaking from the storage area and contaminating ground and surface water. Similarly, other furnaces and solvent or aqueous de-oiling methods are used to remove lubricants and other organic contamination. When brasses or bronzes are melted, zinc is fumed from the furnace; good control of the temperature can minimize this. Fume is collected in the gas extraction system and removed in a fabric filter. The zinc oxide is normally recovered. A degree of fire refining is also carried out and the resulting fumes are taken into account in the design of the fume collection and abatement systems. The processes detailed in the section on applied techniques are techniques to be considered in conjunction with effective fume extraction of launders and casters where needed.

[pic] [pic] Figure 01: Grid Casting Machine Figure 02: Pure Diamond Grid
The potential for dioxin formation during the refining processes for primary and secondary production of aluminum has not been fully investigated. It is recommended that this issue is quantified. The fume collection processes and techniques for are suitable for use with new and existing installations. All the antimony lead is dried by air and that time we get some lead bar which is called antimony lead bar because they give us a special shape of bar. We get antimony lead bar into the furnace for melting of the grid casting machine. Different kinds of activities are solved by this machine.

Battery grids are manufactured by either casting or stamping operations. In the casting operation, lead alloy ingots are charged to a melting pot, from which the molten lead flows into molds that form the battery grids. The stamping operation involves cutting or stamping the battery grids from lead sheets. The grids are often cast or stamped in doublets and split apart (slitting) after they have been either flash dried or cured. The pastes used to fill the battery grids are made in batch-type processes. A mixture of lead oxide powder, water, and sulfuric acid produces a positive paste, and the same ingredients in slightly different proportions with the addition of an expander (generally a mixture of barium sulfate, carbon black, and organic) make the negative paste.

Grid Casting Parameter

| | | | | | |
|Sl. No. |Type of grid |Weight |Height of grid |Width of grid in mm |Thickness |
| | |of grid |in mm | | |
| | |/panel | | |Lug( mm)|Frame(mm) |
|01 |IB120T |208±4 |126±2 |144 |4.15 |4.2 |
|02 |EV170T |205±4 |180±2 |151 |3.55 |3.6 |
|03 |EV180T |210±4 |190±2 |151 |3.55 |3.6 |
|04 |EV2.6 |115±4 |180±2 |151 |2.55 |2.6 |
|05 |N3.2 |254±4 |126±2 |144 |3.15 |3.2 |
|06 |N2.3 |195±4 |126±2 |144 |2.25 |2.3 |
|07 |N1.9 |180±4 |126±2 |144 |1.85 |1.9 |
|08 |N1.7 |160±4 |126±2 |144 |1.65 |1.7 |
|09 |N1.5 |134±4 |126±2 |144 |1.45 |1.5 |
|10 |N1.4 |124±4 |126±2 |144 |1.35 |1.4 |
|11 |N1.2 |114±4 |126±2 |144 |1.15 |1.2 |
|12 |N1.0 |102±4 |126±2 |144 |0.95 |1.0 |
|13 |NS1.5 |100±4 |126±2 |106 |1.45 |1.5 |
|14 |NS1.4 |90±4 |126±2 |108 |1.35 |1.4 |
|15 |NS1.2 |85±4 |126±2 |106 |1.15 |1.2 |
|16 |NS1.0 |76±4 |126±2 |108 |0.95 |1.0 |

Metal may be tapped from the melting furnace where alloy additions are made either directly to a casting system or via a transfer system into a holding furnace (where other alloying additions can be made). The metal is then refined either in the holding furnace or in an inline reactor, to remove gases and other metals generally in the same manner as primary aluminum. Magnesium can be present in secondary aluminum and may need to be reduced. Treatment of molten aluminum with chlorine gas mixtures is used to remove magnesium although sodium aluminum fluoride and potassium aluminum fluoride are also used. The latter material is a by-product of the production of some master alloys.
Large ingots, billets and slabs are cast in the same way as primary aluminum and a range of smaller ingots may also be produced (e.g. for supplying the casting industry) may also be produced in a large variety of alloys depending on the final application. It is also possible to transport molten aluminum by road in special thermally insulated containers to end-users.

Different temperature such as pot, ladle, lead tube and mold temperature must be maintained as specification for each machine. Otherwise, quality grids will not be produced. After grid casting, it is necessary to keep minimum 72 hours for aging purpose. Normally, after 72 hours lead alloy gives again its maximum tensile strength. So in the factory grids are stacking in the floor for 72 hours for automotive battery. After the grid checked by QA department by rolling though a 1”pipe in both side of grids width and length. If there is no crack is found then grid passed for pasting. All grids are randomly checked by QA department.

4. Oxide Unit:

The combustion/oxidation systems used in the production of non-ferrous metals often feature the use of tonnage oxygen directly or oxygen enrichment of air or in the furnace body. This enrichment is used to allow auto-thermal oxidation of sulphide based ores, to increase the capacity or melting rate of particular furnaces and to provide discrete oxygen rich areas in a furnace to allow complete combustion separately from a reducing zone. In this section, first of all we melt all the pure lead bars. After sometime, we get some lead piece from the bar ton pot. There is a rotation process which is 260-270/mins. When the lead go through into the bar ton tank by the force of air then we get some powder that is called oxide of bar ton. It’s factory name is bar ton oxide. That time, the oxide is also melted by 250-380 Degree Celsius. After sometimes, the bar ton oxide get a new color and that is called red oxide. The publisher machine refine the red oxide and it’s density is 1.50 to 1.80.

Rest of the pure lead bar is also used in the casting pot for melting process. In this system, we get some pure lead gutty. The whole process is occurred by a cutting machine. There is ball mill where that gutty is melted by 130 to 165 Degree Celsius. Then we get gray oxide and density 1.20 to 150. For battery oxide is produced by pure lead in a ball mill. Lead oxide produced in a factory. The produced oxide checked by QA department, one hour dropping (four times per shift). Minimum aging period of oxide is 72 hours. For battery oxide red is produced by bar ton oxide and the produced red oxide is checked by QA department.

6.5 Pasting Unit

Paste is the active ingredient of the battery. There are various types of grids. Pasting section is run by a pasting machine. There are three steps in the pasting machine and these are hopper, roller, and at last oven. There is curing chamber where the temperature is 45 to 50 Degree Celsius. In this chamber the maximum humidity is 90 percent. Pasting department carry out the quality passed grey oxide for paste mixing. It holds the charge in the battery which is slowly discharge during the reaction between active mass (paste) and sulfuric acid (electrolyte). Thus paste preparation and proper pasting has the most important impact upon the lifetime and capacity of the battery. Three major paste mixtures produced in the factory are two positive (Auto and IPS) and one negative. A typical pasted plate construction is shown in below.
[pic]

Figure : Flat Pasted Plate
The lattice grid is cast with pure lead, lead-calcium or lead-antimony depending on the size of the plate and the application. Active material is applied as a wet paste and the plate is then cured, dried and formed. When used in repetitive deep cycle operation. such as fork lift truck handling. Glass mats and a perforated plastic retainer are wrapped around the positive plate to minimize the loss of positive active material and to obtain good cycle life. This wrap performs the same function as the retainer tube of tubular positive plates. Positive mixture paste consists of gray oxide, red oxide, sulfuric acid, fiber flock and DM water. Positive mixture paste is contained by 90 percent gray oxide and 10 percent red oxide. Otherwise, the negative mixture paste is made by gray oxide, sulfuric acid, fiber flock, DM water, negative expender and etc. The chemicals are mostly exported from China and Taiwan. During the last stages of charge, oxygen gas is formed at the surface of positive plates. The agitation of gas bubbles streaming from the surface of exposed grid and active material tends to erode the active material which is shed through the glass retainer and settles into the sediment space at the bottom of each cell.

[pic][pic] Figure : Diagram of set up positive and negative plates in a battery

In light cycle or in float service this positive active material shedding is not the major failure mechanism. In these applications the glass mat retainer is lighter, thinner, and the perforated outer wrap is omitted. Both designs depend upon a ribbed micro porous separator adjacent the negative plate to achieve longest life. Pasted plates are made with thin or thick grids depending on the application. In general, when the application demands a high ampere rate for a very short time, it is customary to use many thin plates in a container. Thicker plates with fewer plates per container are used for those applications with relatively low ampere drain for relatively long periods of time. In general, when the service is similar, thin plates will give less life than thick plates. Lead-antimony grids are usually used for daily deep cycle operation. Grids with a lead calcium alloy or pure lead can also be cycled; but repetitive cycles are restricted to a depth less than 20% of capacity plus infrequent operations with a discharge depth as high as 50-60% of the 6-hour to 8-hour rated capacity.

[pic]

In curing step, we want to curing plate for better mechanical strength and bonding. Mainly digital hydrometer with thermometer is used in curing process. After completed pasting another process to be done which is known as curing. To reduce residual lead and produce better mechanical strength by bonding. In curing process, skin dried plate are kept in the temperature and humidity control chamber. In this chamber, the temperature is 40 to 50 degree Celsius and humidity 90 to 99.9 percent. Conditioned positive and negative plates are formed b y using both tackles and formation procedure, after the pasting and curing process, the active materials of both positive and negative plates consists essentially of lead oxide, basic lead sulfate, a small amount of residual lead and moisture, during the formation process plates are electrochemically formed. Both positive and negative plates are immersed in dilute sulfuric acid and DC current in passed converting the negative paste into highly porous spongy lead and the positive paste into highly porous chocolate brown lead oxide.

We want to produced properly conditioned plate as per standard. The plates are successful completion of curing plates are remove from curing room and is allowed to stay minimum 48 hours or more to bring down the moisture quantity inside plate to 1 percent or below. This process is called conditioning.

We want to quality full filling and picking plates for battery. After completed spine grid another step to be done this is known as filling and picking. To equal weight tubular plates after pickling the FLC% below 5% and produce better mechanical strength by bonding. In the filling and pickling process vat temperatures not exceed 55 degree centigrade and FLC not exceed 5%. Formation completed plates are washed by DM water to remove acid from the plates. Within 2 hours of formation, plates are transferred from formation tank to washing tank. After washing plate is dried using drying oven or dry change oven. After formation and drying we can get a good quality plate for battery.

6.6 Assembly Unit

In the assembly section, we arrange all the positive and negative plates in group wise. We want to produce quality full battery assembles for auto, IPS, solar and EV battery. For finish auto, solar and EV battery, we need type wise container, cover, and finished plate. The plates inserting, inter cell welding, heat sealing leak testing, aluminum foiling, bar coding, and packing a quality full battery. Various types of activities is run by assembly unit and these are: Types wise container checking, type wise finished plate checking, type wise separator checking, cell layout, terminal type, inter cell welding checking, shear test, cell short test, leak test, polarity inspection, visual inspection, aluminum foiling checking, serial number checking, bar coding checking, passed sticker attaching, guarantee card [1 year], inserting guarantee card, final quality test. At last, we get a final product.

[pic][pic][pic]

Figure : one year guaranteed Car, Solar, and IPS battery

Chapter: 07

(Conclusive Part)

7.1 Conclusion

Advance Power Electronic Product LTD. Is one of the leading manufacturer of electronic product in Bangladesh. It produces quality product by ensuring modern design and international testing facilities. The industrial training in Advance Power Electric Company Limited helps me various ways in the field of Electrical Engineering. I have studied the battery function, operation and manufacturing process. The study is very useful for me. I have experienced a lot of things which I have only heard or read about. It helps me to gather the experience that, this position is really challenging since everyone who desire being successful in their career in the field of Electrical Engineering. The large number of battery types and manufacturers available to users today can make choosing the right replacement or new battery difficult. It can be hard to separate the facts from the hype. This report contains the assembling and operation of Battery. Now–a–days in everywhere must have two or more power sources used as emergency/backup power sources. In our country Mains supply cannot provide power as continuity power supply. Load shedding is a daily affair in our country. So we need emergency/backup power sources and in the same time we need Battery to start the emergency source. My effort will be successful if this report makes the analyzer satisfy to understand the technology used in manufacturing Battery which is very necessary as a useful power system in every moment.

7.2 Recommendation

1. As reported, the quality of the reports submitted by the various sources was high but some gaps in the data were identified. In battery, the plates are most sensitive parts. So, in assembly section they will must be use with carefully.

2. Sometimes the insulation of the battery oil can be disrupted because of quality issues which may result fire. So, before using, the company should assure the quality of oil.

3. In the workshop I have seen trained engineers are not available all the time. The foreman and Technician manufacture various control panels without mentioning some technical requirements suppose, clearance, loose connection etc. Sometimes they fall in trouble. To overcome these problems the company has to assign a trained engineer all the time at the workshop to guide the foreman and technicians.

4. Emerging techniques have been reported for most of the metal groups. In particular the use of inert anodes for the primary production of system appears to be slow to emerge but could offer several major environmental advantages if the work is successful.

5. Process control equipment for some furnaces and processes, particularly some blast furnaces, is capable of improvement. It is recommended that this work is carried out and reported for the next revision of this document.

6. Finally, I want to say that, every student should take the Industrial training because it is a bridge from theory to real practice. Especially, the students, who are now looking for jobs, internship program is very much helpful for them. By attending this program, a student can gain a lot of knowledge and experience. This program teaches a student to work with new people in new environment.

7. It had been my dreaming to study engineering and has been studying it for four years. I always cherished my dream about working in a related practical field. Finally It was an unique opportunity to work in a company like Advance Power Electric Company Limited. They appreciated my work while working there and that is what inspired me the most. I do not say that, this company is the best but I would like to recommend this company to upcoming intern students who has interest in electronic device of battery.

7.3 References

1. www.advancepower.com

2. www.wikipedia.org

3. www.electronicsweekly.com/design

4. Product catalogue of APECL

5. Power Electronics, By H. Rashid

6. T. Yanagihara and A. Kawamura, Residual Capacity Estimation of Sealed Lead-Acid Batteries for Electric Vehicles, IEEE Power Engineering, Power Conversion Conference

7. F. Lacressonniere, B. Cassoret, and J. Brudny, Influence of a Charging Current with a Sinusoidal Perturbation on the Performance of a Lead Acid Battery, IEEE Proceedings on Electric Power Applications, Vol. 152

8. J.R. Woodworth, S.R Harrington, J.D. Dunlop, et al, “Evaluation of the Batteries and Charge
Controllers in Small Stand-alone Photovoltaic Systems”, First World Conference on Photovoltaic Energy Conversion, Hawaii, Dec. 1994

9. J.P. Dunlop, “Venice Photovoltaic Lighting Systems Evaluation Report,” Florida Solar Energy
Center, Contractor Report, Jan. 1997

10. L.T. Lam, H. Ozgun, L.M.D. Cranswick, and D.A.J. Rand, “Pulsed-current formation of tetrabasic lead sulfate in cured lead/acid battery plates,” Journal of Power Sources, 42, 1993

7.4 Appendix