The battery (1) comprises: an enclosure (5) internally delimiting a volume (7) for receiving the electricity storage cells (3); a heat exchanger (11) comprising an upper metal plate (13) defining the bottom of the enclosure (5), a bottom plate (15) delimiting with the upper plate (13) a circulation volume (17) for a heat transfer fluid, and a plurality of upper fins (19) housed in the circulation volume (17) and arranged to transmit forces between the upper and bottom plates (13, 15); a protective plate (23) covering the bottom plate (15) and defining with the bottom plate (15) a lower volume (25); lower stiffening fins (27) housed in the lower volume (25) and arranged to transmit forces between the protective plate (23) and the bottom plate (15), the bottom plate (15) forming with the lower fins (27) and the protection plate (23) a rigid frame (28) absorbing most of the forces to which the battery (1) is subjected.