Secondary cells are rechargeable electrochemical storage devices. To distinguish them from batteries, secondary cells are referred to as accumulators.
Accumulators generate their electrical energy through electrochemical conversion. As with primary cells, the voltage level generated by secondary cells depends on the materials used and the electrochemical voltage series. Whereby the voltage results from the electrode material and its different voltage values of the two chemical elements. This results in the different nominal voltages of the batteries.
Secondary cells convert chemical energy into electrical energy when a consumer is connected. The process is reversible, i.e., unlike primary cells, secondary cells can be recharged after discharge. The charging cycles depend on the battery type and range from 500 to 3,000 recharges for common battery types. Special developments achieve over 100,000 charge cycles.