The accumulator has temp. regulator. Adjacent cells (1) are separated by a thermally insulating solid sheet (2) of thermal conductivity coefficient between 0.01 and 0.02 W/(m*K), whereby the thermal resistance of the sheet is greater by a factor of at least K than that of the cell. The cell is connected to a heat exchanger in a region free from insulation. The thermal resistance of the heat exchanger in the direction of the adjacent cell is at least a factor K greater than that of the cell. The thermal resistance of the heat exchanger in the direction of the temp. control medium is at least 10 times less than that of the cell. K is the ratio of the energy content of the cell to that required for thermally induced cell damage for a certain upper operating temp. limit.
