Battery Theory Summary

Batteries BATTERY THEORY Summary Battery theory is summarized below. Battery Theory Summary The purpose of a battery is to store chemical energy and to convert this chemical energy into electrical energy when the need arises. A voltaic cell develops a potential difference when electrodes of two different metals are immersed in an electrolyte. One electrode accumulates a positive charge. The potential difference is due to the difference in charge between the two electrodes. The chemical equation for a lead-acid battery during discharge is: . PbO₂ Pb 2H₂SO₄ discharge � 2PbSO₄ 2H₂O The chemical equation for a lead-acid battery during charge is: . PbO₂ Pb 2H₂SO₄ charge � 2PbSO4 2H₂O When a lead-acid battery is discharged, electrolyte and the active material on the plates of the battery are consumed to produce water and lead sulphate. When a lead-acid battery is charged, electrical energy is added to the battery, causing the water and lead sulphate to be consumed and produce electrolyte and active material. Since specific gravity of a lead-acid battery decreases proportionally during discharge, the value of specific gravity at any given time is an approximate indication of the battery’s state of charge. Rev. 0 Page 9 ES-04