A sealed accumulator container (2) intended to contain an electrochemical bundle (9), the container comprising a wall forming a bottom (3) in an electrically conducting material comprising: a peripheral portion (3a), a cap (3c), an embrittled portion (3b) delimiting the cap, joining the peripheral portion to the cap, adapted so as to break upon overpressure inside the container, in which container is positioned an electrically conducting deformable membrane (10) electrically connecting electrodes of same polarity of an electrochemical bundle to the cap, and in which container, overpressure causes deformation of the membrane, this deformation causing failure of the embrittled portion.