The electrochemical voltage series forms the basis for determining the nominal battery voltage. Batteries and rechargeable batteries work with two electrodes that exchange ions via an electrolyte and thus generate voltage. Depending on the electrode material, different voltage values are generated.
Since many materials such as zinc, manganese, titanium, beryllium, gold, chromium, lithium, copper, iron, oxygen, tin, nickel, cadmium, lead, etc. can interact with each other, the possible combinations for electrochemical reactions run into the hundreds. For this reason, the electrochemical voltage series limits the number of possible combinations by specifying the voltage between a metal and a standard hydrogen electrode.
From the voltage values, which can be positive or negative, the nominal voltage of the battery can be calculated. For example, if a lead electrode and a magnesium electrode are immersed in an electrolyte, the nominal voltage is 2.23 V (2.36 V (Mg) - 0.13 V(Pb)).