131 in order to weld the collector 13 and the tamped portion 30 t together and on the other hand through the apertures bounded by the tabs 132 in order to weld the held folded portions 31 together during the welding the ribs 131 facilitate removal of the heat to the periphery of the weld bead independently of how the aforementioned welds are produced a conventional procedure is followed to finalize the definitive accumulator thus although not shown the bundle is introduced with the collector 13 into a rigid container made of aluminum forming only the lateral jacket 7 of the casing 6 care is in particular taken in this step to ensure that the tongue 130 does not hinder the introduction to this end the tongue is advantageously bent upward the collector 14 is welded to the bottom 8 of the casing 6 the collector 13 is welded to a negative pole 50 forming a feedthrough of a cover 9 of the casing 6 the cover 9 is then welded to the rigid metal container 7 next a step of filling the casing 6 is carried out using an electrolyte through a through aperture not shown that is arranged in the cover 9 according to the invention because of the height difference between the plinth formed by the tamped portion 30 t and the folded portions 31 the filling with electrolyte is facilitated and more rapid production of the li ion accumulator according to the invention ends with the blocking of the filling aperture other variants and improvements.