Traction Batteries
A traction battery consists of several cells of 2V. When those cells are connected in series, you get higher voltages. A traction battery of 24 volts has 12 cells, a 48 volts battery has 24 cells, a 80 volts battery has 40 cells. To recharge a battery, the cell voltage has to be increased to above 2 volts by an external voltage source.
Traction batteries differ from starter batteries because they have been developed to provide a certain amount of energy for longer periods. As a result, traction batteries usually have a much higher capacity than starter batteries.