Battery production line: Start with a medium sized plant and upgrade to a bigger one

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India has just a handful of large battery manufacturers, with a good number importing batteries and selling them under their own brand names. However, these players could decide to start their own manufacturing facilities in India.

By Sandhya Malhotra

Saturday, July 17, 2010: All batteries go through similar procedures to create electricity. A battery transforms chemical energy directly into electrical energy through an electro-chemical process. However, variations in materials and the construction of the battery have produced different types of batteries. “Strictly speaking, what is commonly called a ‘battery’ is actually a group of linked cells. Manufacturing process of all batteries is almost the same except for the difference in design, raw materials and the parts used,” says S K Prabhu, principal consultant, lead technology, Navarees Consultants.

Lead acid battery market can be divided into two broad sectors—industrial and automotive batteries. In this article, we will look into the manufacturing of industrial batteries, which is a faster growing market compared to the automotive batteries market. There are three categories in this market segment—the flooded battery, semi-maintenance free battery and the sealed maintenance free (also called the valve regulated lead acid) battery. These are used extensively in the telecom, railways, power and other industrial sectors.

According to Kapil Sood, CEO, Fusion Power Systems, “Developments in battery technology have been slow but steady. Battery technology is complex. A small change in a manufacturing parameter can lead to a substantial change in battery performance. It, therefore, requires strict control of manufacturing parameters, apart from focusing on technological developments.” Sood imports Amptek branded industrial batteries and adds value in terms of redesigning or adapting the battery to local climatic conditions.

Size of the plant

Anil Joshi, general manager, projects, Artheon Electronics, says, “The most significant components needed to successfully establish a manufacturing plant are: an understanding of machinery, research work and consistency. The size of the plant depends on the volume of business you want to do, the quantum of funds you have at your disposal, and the turnover target you plan to achieve.” The plant can be set up within a 50 sq m room or can be spread over a 5,000 sq m plot. The minimum investment required to establish a battery manufacturing plant is Rs 500,000.

Production line

The important elements of the infrastructure required to manufacture industrial batteries include grid casting machines, oxide mill, paste mixing machine, pasting machine, plate parting, assembly line, acid filling and battery charging machines. These processes require semi and fully automatic machines. “A fully automatic production line for batteries is quite expensive. A manual or semi-automatic production line is, therefore, suggested for the initial stages. It is better to have a medium sized plant and then upgrade to a bigger one. This will cut down on costs,” says DD Sharma, CEO, Fluid-O-Matic.

HBL Power Systems has a combination of an automated and semi-automated production line. “Some of our machines/fixtures are designed and manufactured inhouse. While some critical machines like grid casting machines, paste mixers, pasting, curing and drying chambers, chargers and dischargers have been imported,” says Avnish Arora, vice president, sales, HBL Power Systems.

Okaya Power Ltd, on the other hand, has a fully automated production line. “Our plant is equipped with the most advanced machines acquired from international battery equipment manufacturers such as TBS, Tekmex, Wirtz, Mac, Conbro, Bitrode, Farmer, Hadi, Oxmaster and Fei,” says Rajesh Gupta, director, Okaya Power Ltd.

Artheon Electronics has an automatic plate making production line and a semi-automatic assembly production line. “We have imported some machines from the US and some are from India,” says Joshi.

How to select machines

Manufacturers of industrial battery can use machines and equipment made in India or imported into the country. They need to research the market before buying the machines. “Don’t buy what others sell; buy what you require,” says Prabhu. The decision on whether to use indigenous or imported machinery depends upon the volume of batteries you aim to produce, the machinery’s track record regarding its consistency in performance, and the costs, adds Prabhu.

Sood, too, emphasises on indepth research before purchasing a machine for battery manufacturing. “Due to lack of technical capabilities and research work, many companies had to shut down their operations in a short span of time. There are various sources for semi-automatic and fully automatic machines. However, the important factors governing sourcing decisions are machine capability, high performance, consistency, reliability and service.”

Depending upon the application and market requirements, a battery is first designed and accordingly, the manufacture of the prototypes is planned. “We spent almost six months in identifying the right supplier and took specialised services of experts in designing the battery plant,” says Joshi.

Adds Arora, “Before buying the machines, we made a study regarding their suitability to our manufacturing methods and also about the feasibility of integrating them with the existing facilities. Most importantly, we carried out modifications in order to have 100 per cent utilisation of the machines.”

“We did rigorous research work while selecting the machines most appropriate to our needs. We had visited the best international battery manufacturing plants located in Germany, Japan, Spain, Italy, Puerto and Taiwan in search of the best machines and processes suitable for our plant,” says Gupta.

Machine maintenance

Proper and timely maintenance of machines is essential to enhance their life. Joshi suggests following the total productive maintenance (TPM) methodology. “Battery-making machines require normal maintenance regimes. This task can be divided into preventive and corrective (breakdown) maintenance.”

Says Gupta, “We have highly sophisticated CNC and PLC controlled machines, which are maintained by qualified electronics engineers and computer professionals. We have a cross functional team of electronics engineers, mechanical engineers and tool room professionals. A sophisticated software system controls all machines in order to manage traceability and sourcing.”

Arora explains, “Most of the machines come with maintenance/instruction manuals and drawings. Such basic information is useful to carry out minor repair work. However, critical spares have to be carefully planned.”

After sales maintenance contracts for these machines can add up to 10-15 per cent of the machine’s cost, depending on the vendor. However, self maintenance is possible if the manufacturer has a prompt spares shipping service.

Usually, after sales service is provided by the manufacturers of the machines. Imported machinery is serviced by authorised distributors in India. However, Gupta says, “It is generally observed that local support engineers are familiar with only a few types of machinery. Also, calling engineers and technicians from abroad for installation, commissioning and servicing of machines is very challenging and time consuming at times.”

Certification required

Prior to setting up a battery manufacturing plant, stringent pollution control measures need to be implemented. There are several certifications one should obtain before embarking on manufacturing. These include an industrial manufacturing licence, certification from Pollution Control Board (PCB), electricity boards, labour commissioner, local authorities, IEC/IS product and ISO certification. Says Arora, “A certificate from PCB is mandatory. Yet, one needs to regularly monitor air, soil and water quality.”

Environment friendly manufacturing

Environmental controls required for battery manufacture are technology intensive and hence expensive. So, many manufacturers shy away from implementing the required safety measures. Although making batteries has some environmental obstacles, none are insurmountable. One needs to follow the strict guidelines laid down by the PCB. The plant should be spacious and well ventilated, and there should be a good exhaust system for fumes and gases.

“Apart from relying on the most advanced machinery and technology, we are careful to protect the environment in our plants and ensure effective waste water treatment facilities. Treated water from these facilities has content levels well within globally-recognised standards for safe water,” says Gupta.

Sood shares, “During battery production and recycling, one must make sure of zero wastage of sulphuric acid and hazardous lead. All discarded materials should be recycled. Besides following strict environment norms, proper health check ups for workers and safety measures like the wearing of caps, masks, etc, are essential. Periodical check up of employees’ blood to ascertain the level of lead consumed by them is a must.”

Joshi points out that air, soil and water near the plant and inside the plant are the major check points. Air should be monitored at a prescribed frequency to check if the production facility is operating within the permissible limits regarding lead and acid fumes.

Tips for setting up a battery production unit

Anil Joshi, general manager, projects, Artheon Electronics, recommends taking the opinion of or engaging experts/consultants right from the stage when the battery is being designed. Besides, good planning is required to ensure availability of raw materials, trained manpower and also to make sure that the unit is reasonably away from prescribed city limits, preferably in a government approved industrial area or at government approved smelters.

“My advice to those who are planning to enter battery manufacturing is that, they should have the financial resources to bear the recurring expenses, certifications and government licences. Above all, they should be passionate about producing the best quality of batteries, as many companies have sunk because they could not produce good quality batteries,” says Rajesh Gupta, director, Okaya Power Ltd. “Nowadays, battery manufacturers offer long warranty periods of up to four years. Hence, it is imperative for the manufacturers to have fully automated and integrated plants with high end machinery and equipment. We strongly recommend Japanese, European and US machines,” he says.

Kapil Sood, CEO, Fusion Power Systems, points out that to manufacture batteries one should use high quality raw materials like pure lead instead of recycled lead, lead-calcium based plates, phenolic resin, polyethylene separators, PVC separators or absorptive glass mat (AGM) separators depending on the battery to be produced. Plant operators should ensure the separators have superior endurance and high porosity, which will allow easy enveloping on the assembly line. “These separators have high absorbency and durability, since they are highly resistant to battery acid, oxidation and heat, and can maintain their shape and strength even after prolonged exposure to severe environmental conditions,” he adds.

According to S K Prabhu, principal consultant, lead technology, Navarees Consultants, a startup should make sure about the application, product specifications, cost and design of the product through effective costing and performance. “It should plan the manufacturing process and its stabilisation. One can also appoint an experienced technical professional or consultant who can help the company at every stage of manufacturing any type of battery,” he adds.

Machines for battery manufacturing

Grid casting is the process of manufacturing positive and negative grids by melting lead antimony or lead-calcium alloy at 500 to 550 degrees celsius in a crucible, and pouring it into block moulds with the help of a grid casting machine. However, for 12V monobloc batteries, which have very thin plates, the grid is generally made in various sizes and shapes to suit specific requirements.

Paste mixing: Mixing of the constituents of active materials is carried out to achieve a homogeneous composition of the constituents, additives and binders. The basic raw materials used in paste mixing are lead sub-oxide (LSO), sulphuric acid and DI water along with additives and binders in predefined quantities.

Pasting is the process of applying active material paste over the grid to form the pasted plate.

Curing and drying: The pasted plates are then cured and dried to improve the cohesion and adhesion of the active material to the grid.

Cell assembly: This process involves exposing the plates to steam and subsequently drying in an oven.

Buffing is done to remove the oxide layer formed over the plate lugs. The positive and negative plate lugs are buffed by means of a circular wire brush rotating at a high speed.

Wrapping: Both positive and negative plates are grouped alternately in a group box along with the separator and bottom cap (for the negative plates). The number of positive and negative plates assembled depends on battery AH capacity.

Group burning is the process of melting and joining the top portion of the lugs with the extended portion of the terminal pillars using an oxy-acetylene flame torch. All positive plates are welded together to form the positive terminal. Similarly, all negative plates are welded together to form the negative terminal.

Containerising: The group burnt stack is then tightly placed in a PP/ABS container under some compression with the help of a pneumatic machine.

Heat sealing: After containerising, the container and the lid are joined by melting, to form a sealed cell. This process is known as heat sealing. A heat sealing machine is used in this process.

Terminal assembly is the process of assembling the terminal components and tightening the terminal nut to the required torque. The terminals are identified with red colour for the positive terminal and black for the negative.

Leak testing: Sealed cells are then tested to detect any leaks at various joints as well as around the terminal pillar.

Acid filling: Electrolyte filling is the process of adding sulphuric acid of a specific gravity and quantity into the cell before carrying out the initial charging.

Formation is the process of converting the cured and dried plates into positive and negative plates by passing charging current. Formation involves the stages of charging, discharging and rest cycles (including formation discharge).

Battery assembly: The cells are then washed and assembled in suitable steel racks/modules, which are stacked as per the general arrangement drawing. The final inspection is then carried out.

Battery charging process: Batteries are moved to forced water cooled charging bays for final charging. These batteries are then connected to fully automatic battery chargers and charged in a three step charging process. Acid gravity and temperature are strictly checked every hour.

Battery washing and drying: Charged batteries are taken by automatic conveyors through a battery washer and dryer machine.

Battery checking process and date coding: All batteries are subjected to a one time high rate discharge (HRD) test to ensure optimum performance. They are then passed through a computerised automatic date code process machine, which puts the dispatch code and serial number on each battery.

Source: HBL Power Systems and Okaya Power

Electronics Bazaar, South Asia’s No.1 Electronics B2B magazine

 

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