Question

short note on lead acid cell

Answer 1

In the fully charged state, the negative plate consists of lead, and the positive plate lead dioxide, with the electrolyte of concentrated sulfuric acid. Overcharging with high charging voltages generates oxygen and hydrogen gas by electrolysis of water, which is lost to the cell.

Answer 2

The lead acid battery was invented in 1859 by French physicist Garston Planted and is the oldest type of rechargeable battery.  Despite having a very low energy to volume ratio, it's ability to supply high surge currents means that the cell have a relatively large power to weight ratio.