Abstract: It is described a bipolar separator for polymer membrane fuel cell stacks, delimited by two sheets provided with fluid passage holes connected by means of a corrugated element and comprising a passage section for a thermostatting liquid, which allows to achieve the withdrawal of heat from the adjacent cells and the humidification and distribution of gases with a single integrated piece, simplifying the assembly and the hydraulic sealing of the stack.

Abstract: It is described a method of electrical by-passing of an elementary electrochemical cell, for instance a fuel cell, inserted in a filter-press structure delimited by electrically conducting bipolar sheets and provided with perimetral sealing gaskets, comprising short-circuiting the cell by insertion of a conductive material within recesses realised by perforation of materials interposed between the bipolar sheets. The gaskets and the bipolar sheets may be provided with sites predisposed to the perforation, for instance notches for a drilling tip, or gasket regions of decreased hardness.