The wet cell lead acid battery is the main storage device in automotive use. An automotive battery can supply very high discharge currents while maintaining a high voltage - useful for cold starting. It gives a high power output for its compact size, and it is recharge-able.
The most common standard 12-volt car batteries consist of six cells, each of a nominal 2 volts. Each cell contains two electrodes, one of lead (Pb) and the other of lead peroxide (PbO2), in an electrolyte of dilute sulfuric acid (H2SO4). As the battery discharges, both the electrodes turn into lead sulfate and the acid turns into water. Recharging the battery reverses this process.
In a conventional open wet-cell battery, overcharging will generate hydrogen and oxygen gas, a highly explosive mix. The sulfuric acid in batteries can also be very harmful, so batteries should always be handled with care, and only when wearing protective clothing.
