Lead-Acid Batteries Tutorial
- A lead-acid battery is made up of a number of lead-acid galvanic (voltaic) cells connected up in series.
- When a lead-acid cell is producing electricity (discharging) it is converting chemical energy into electrical energy.
- Discharging a lead-acid battery is a spontaneous redox reaction.
- When a single lead-acid galvanic cell is discharging, it produces about 2 volts.
- 6 lead-acid galvanic cells in series produce 12 volts.
The battery in a petrol or diesel car is a 12 volt lead-acid battery.
- Lead-acid cells are rechargeable because the reaction products do not leave the electrodes.
- A lead-acid galvanic cell can be recharged by connecting the :
(i) negative terminal of a battery charger to the negative terminal of the galvanic cell
(ii) positive terminal of a battery charger to the positive terminal of the galvanic cell.
(iii) A lead-acid battery can therefore be recharged in a similar way.
- Recharging a lead-acid galvanic cell (or a battery) converts electrical energy from the recharger back into chemical energy stored in the galvanic cell (or battery).
- Recharging a lead-acid cell is therfore a non-spontaneous electrolytic process.
- Galvanic cells which can be recharged are known as secondary cells.
Lead-acid cells are secondary cells.