How is a Battery Made?

How is a Battery Made?

There is an excellent description of how battery is made at the Battery Council International (BCI) web site at http://www.battery.council.org/made.html. We have reproduced a tiny part of it here as it is very good general knowledge and could extend your battery life. A twelve-volt car battery is made up of six cells, each producing 2.1 volts and that are connected in series from positive to negative. Each cell is made up of an element containing positive plates that are all connected together and negative plates, which are also all connected together. They are individually separated with thin sheets of electrically insulating, porous material “envelopes” [labelled #3 in the diagram below] that are used as spacers between the positive (usually light orange) and negative (usually slate grey) plates to keep them from electrically shorting to each other. The plates [#2 in the diagram below], within a cell, alternate with a positive plate, a negative plate and so on. A plate is made up of a metal grid that serves as the supporting framework for the active porous material that is “pasted” on it. In Europe, using solid lead positive “Plante” plates is popular.

After the “curing” of the plates, they are made up into cells, and the cells are inserted into a high-density tough polypropylene or hard rubber case [#1 in the diagram above]. The cells are connected to the terminals [#5 in the diagram above], and the case is covered and then filled with a dilute sulphuric acid electrolyte [#4 in the diagram above]. The battery is initially charged or “formed” to convert yellow Lead Oxide (PbO or Litharge) into Lead Peroxide (PbO₂), which is usually dark brown or black.

The electrolyte is replaced and the battery is given a finishing charge. Some batteries are “dry charged” meaning that the batteries are shipped without electrolyte and it is added and recharged when they are put into service.

Why do batteries die?

In cold climates, a battery normally “ages” as the active positive plate material sheds (or flakes off) due to the expansion and contraction that occurs during the discharge and recharge cycles. A brown sediment, sludge or “mud,” builds up in the bottom of the case and can short the cell out. In hot climates, additional causes of failure are positive grid growth, positive grid metal corroding in the electrolyte, negative grid shrinks, plates buckling, and loss of water. Deep discharges, heat, vibration, over charging, under charging and non-usage accelerate this “aging” process. Another major cause of premature battery failure is lead sulfation. This was mentioned last month in the story on MegaPulse. Using tap water to refill batteries can produce calcium sulphate, which also will coat the plates and fill pores. Recharging a sulphated battery is like trying to wash your hands with gloves on. When the active material in the plates can no longer sustain a discharge current, and the battery “dies”.

Most of the “defective” batteries returned to manufacturers during free replacement warranty periods are good. This suggests that most sellers of new batteries do not know how to, or fail to take the time to properly load test or recharge them.

All of the above info can be found on www.uuhome.de/william.darden/dcfaq.htm This excellent site has a HUGE FAQ on deep cycle batteries and is well worth the hour or so it takes you to plough through it. We have only précised a very small amount to whet your appetite so to speak.

Bob Eustace