Abstract: The invention relates to a cooling system for a fuel cell (2), comprising a main heat-transfer-fluid circuit including a main circulation pump (6) and a heat exchanger (8) with the exterior, which feed an upstream pipe (12) supplying the fluid to the cells (4) of the fuel cell, said fluid leaving the cells via a downstream pipe (14) in order to return to the main pump. The system is characterised in that a secondary circuit, comprising a secondary circulation device (30) that circulates the fluid in an alternate manner, is connected in parallel with the main circuit to the upstream (12) and downstream (14) pipes and in that one or more controlled valves (10, 16) allow the main circuit and the secondary circuit to operate independently.

Abstract: The invention relates to a monomer (6, 14) carrying an imidazole-type heterocycle (3). According to the invention, the chemical structure of said monomer (6, 14) comprises at least one unit of formula (I) wherein R1 comprises an alkenyl grouping and R2 comprises a grouping for protecting one of the nitrogen atoms of the heterocycle. The invention also relates to a monomer carrying a benzimidazole-type heterocycle, and to protected polymers obtained from said monomers, deprotected polymers produced by the protected polymers, a proton exchange membrane based on deprotected polymers, and a fuel cell provided with said membrane. Furthermore, the invention relates to methods for producing the above-mentioned monomers and polymers.

Abstract: The invention relates to a cooling system for a fuel cell, comprising a main heat-transfer-fluid circuit including a circulation pump (6) and a heat exchanger (8) with the exterior, which feed an upstream pipe (12) supplying the fluid to the cells (4) of the fuel cell, said fluid leaving the cells via a downstream pipe (14) in order to return to the main pump. The invention is characterized in that the main circuit comprises a three-port controlled valve (10, 16) on each upstream (12) and downstream (14) pipe, the third available port (10c) of the upstream pipe (12) being connected to the inlet of the pump (6) and the third available port (16c) of the downstream pipe (14) being connected to the outlet of the pump in order to establish a secondary fluid circuit.

Abstract: The invention relates to a monomer (6, 14) carrying an imidazole-type heterocycle (3). According to the invention, the chemical structure of said monomer (6, 14) comprises at least one unit of formula (I) wherein R1 comprises an alkenyl grouping and R2 comprises a grouping for protecting one of the nitrogen atoms of the heterocycle. The invention also relates to a monomer carrying a benzimidazole-type heterocycle, and to protected polymers obtained from said monomers, deprotected polymers produced by the protected polymers, a proton exchange membrane based on deprotected polymers, and a fuel cell provided with said membrane. Furthermore, the invention relates to methods for producing the above-mentioned monomers and polymers.

Abstract: The invention relates to a monomer (6, 14) carrying an imidazole-type heterocycle (3). According to the invention, the chemical structure of said monomer (6, 14) comprises at least one unit of formula (I) wherein R1 comprises an alkenyl grouping and R2 comprises a grouping for protecting one of the nitrogen atoms of the heterocycle. The invention also relates to a monomer carrying a benzimidazole-type heterocycle, and to protected polymers obtained from said monomers, deprotected polymers produced by the protected polymers, a proton exchange membrane based on deprotected polymers, and a fuel cell provided with said membrane. Furthermore, the invention relates to methods for producing the above-mentioned monomers and polymers.

Abstract: The invention relates to a cooling system for a fuel cell, comprising a main heat-transfer-fluid circuit including a circulation pump (6) and a heat exchanger (8) with the exterior, which feed an upstream pipe (12) supplying the fluid to the cells (4) of the fuel cell, said fluid leaving the cells via a downstream pipe (14) in order to return to the main pump. The invention is characterised in that the main circuit comprises a three-port controlled valve (10, 16) on each upstream (12) and downstream (14) pipe, the third available port (10c) of the upstream pipe (12) being connected to the inlet of the pump (6) and the third available port (16c) of the downstream pipe (14) being connected to the outlet of the pump in order to establish a secondary fluid circuit.

Abstract: The invention relates to a cooling system for a fuel cell (2), comprising a main heat-transfer-fluid circuit including a main circulation pump (6) and a heat exchanger (8) with the exterior, which feed an upstream pipe (12) supplying the fluid to the cells (4) of the fuel cell, said fluid leaving the cells via a downstream pipe (14) in order to return to the main pump. The system is characterised in that a secondary circuit, comprising a secondary circulation device (30) that circulates the fluid in an alternate manner, is connected in parallel with the main circuit to the upstream (12) and downstream (14) pipes and in that one or more controlled valves (10, 16) allow the main circuit and the secondary circuit to operate independently.

Abstract: The invention relates to a method for operating a fuel cell (2), which is to be implemented by means of a control computer (10) that drives the level of current generated by the cells of the fuel cell, said fuel cell including a means for tracking the temperature of the cells, said method being characterized in that it comprises the following steps: when starting the operation of the fuel cell, if the temperature of the cells is at a sufficiently low level, particularly less than 0° C., driving a series of cycles of current intervals including, alternately for each cycle, a low non-zero current (Imin), and then a current interval comprising raising and lowering the strength of the current at programmed speeds.

Abstract: The invention relates to a current collecting plate (50) for a fuel cell. According to the invention, the plate comprises a substantially constant thickness of an electrically conductive material along the stacking axis of the cells of the fuel cell, forming a plane at the end of the stack in order to collect the current from the fuel cell. The invention is characterised in that it comprises holes (52) pierced in the thickness of the material, extending parallel to the plane of the plate.

Abstract: A fuel-cell stack including a stack of fuel cells with intermediate conductive bipolar plates. The bipolar plates include internal flow channels for flow of a heat-transfer fluid. The channels are connected to a circuit of a cooling system. Only some of the bipolar plates include internal flow channels that are temporarily or permanently not in service.

Abstract: Bipolar plate for a fuel cell, of the type comprising a cathode bipolar half-plate and an anode bipolar half-plate which are secured to each other, each bipolar half-plate (1) being constituted by a plate which comprises, in the central portion thereof, an active zone (2) and, at the peripheral portion thereof, a plurality of cut-outs (5) which are intended to constitute at least two oxidant units, at least two fuel units and at least two heat-exchange fluid units, at least one bipolar half-plate (1) comprising at least one connection between a peripheral cut-out (5) and the active zone (2), and comprising, at the periphery thereof, at least one hollow housing (140) which is intended to receive a connector (141) for electrical measurement.

Abstract: Bipolar plate for a fuel cell, of the type comprising a cathode bipolar half-plate and an anode bipolar half-plate which are secured to each other, each bipolar half-plate (1) being constituted by a plate which comprises, in the central portion thereof, an active zone (2) and, at the peripheral portion thereof, a plurality of cut-outs (5) which are intended to constitute at least two oxidant units, at least two fuel units and at least two heat-exchange fluid units, at least one bipolar half-plate (1) comprising at least one connection between a peripheral cut-out (5) and the active zone (2), and comprising, at the periphery thereof, at least one hollow housing (140) which is intended to receive a connector (141) for electrical measurement.

Abstract: The invention relates to a monomer (6, 14) carrying an imidazole-type heterocycle (3). According to the invention, the chemical structure of said monomer (6, 14) comprises at least one unit of formula (I) wherein R1 comprises an alkenyl grouping and R2 comprises a grouping for protecting one of the nitrogen atoms of the heterocycle. The invention also relates to a monomer carrying a benzimidazole-type heterocycle, and to protected polymers obtained from said monomers, deprotected polymers produced by the protected polymers, a proton exchange membrane based on deprotected polymers, and a fuel cell provided with said membrane. Furthermore, the invention relates to methods for producing the above-mentioned monomers and polymers.

Abstract: The invention mainly concerns a fuel cell seal (52) designed to be affixed on a bipolar plate (22) in the form of a membrane whereof the profile corresponds approximately to the peripheral frame (50) of the bipolar plate (22) and comprising a central opening (66) coinciding approximately with the central zone (46) dispensing the reagents of the bipolar plate (22). The invention also concerns a fuel cell comprising an electrode membrane assembly (70) which includes in particular an active region (74), which is the site of anode and cathode reactions, and a peripheral frame (75) and which is sandwiched between two bipolar plates (22) whereon is affixed the inventive seal (52).

Abstract: The invention mainly concerns a fuel cell seal (52) designed to be affixed on a bipolar plate (22) in the form of a membrane whereof the profile corresponds approximately to the peripheral frame (50) of the bipolar plate (22) and comprising a central opening (66) coinciding approximately with the central zone (46) dispensing the reagents of the bipolar plate (22). The invention also concerns a fuel cell comprising an electrode membrane assembly (70) which includes in particular an active region (74), which is the site of anode and cathode reactions, and a peripheral frame (75) and which is sandwiched between two bipolar plates (22) whereon is affixed the inventive seal (52).

Abstract: A method of keeping an aqueous solution of sodium borate liquid at a storage temperature, in which method, in order to pass said solution from an initial temperature to the storage temperature, said aqueous solution of sodium borate is subjected to heat treatment comprising at least one cooling or heating operation at a speed lying in the range 1° C./min to 100° C./min, to reach a holding temperature lying in the range ?50° C. to +200° C., followed by holding the holding temperature for a time lying in the range 1 s to 100 h, followed by cooling or heating at a speed lying in the range 1° C./min to 100° C./min. Use of the method in a method of supplying hydrogen for a fuel cell.