Primary cells are non-rechargeable electrochemical storage devices. They are batteries that generate their electrical energy through electrochemical conversion.
As with secondary cells, the voltage level generated by primary 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.
Primary cells convert chemical energy into electrical energy when a load is connected. The process is not reversible, i.e., unlike secondary cells, primary cells cannot be recharged after discharge. They must be disposed of.