Abstract: The invention relates to a battery module (10) comprising a module management system (11) and at least one battery cell (30) having a cell voltage. The at least one battery cell (30) is capable of assuming: —a first operating mode (Mod1) in which the battery cell (30) undergoes discharge, —a second operating mode (Mod2) in which the battery cell (30) does not undergo discharge. The module management system (11) is configured to decide to place the battery cell (30) selectively in one of the operating modes (Mod1, Mod2) depending on the cell voltage. The invention also relates to an energy storage unit (1) comprising at least two of said battery modules (10). Finally, the invention relates to a method for managing such an energy storage unit (1).