The invention relates to a battery system, comprising a battery module, which comprises a first high-voltage connection, a second high-voltage connection and a multiplicity of battery cell modules which are connected in series between the first and second high-voltage connections, and a switching matrix. The method includes determining whether a pair of public and private keys that have already been used in a first encryption process are still usable; and reusing the pair of public and private keys in a second encryption process if the pair of public and private keys are determined as being reusable. The metal plate assembly includes an inlet section for introducing a coolant into the plurality of cooling channels and an outlet section from which the coolant exits the plurality of cooling channels.