Recirculation loops for fuel cells

Abstract

The invention relates to a recirculation loop (11R or 12Ra) for the gas circuit of a fuel cell (1a), wherein the recirculation loop forms one of the two anode or cathode circuits starting from a fuel cell stack (1) and terminates in the connecting duct of one of the two supply lines, either on the fuel gas supply duct (11A) or on the oxidant gas supply duct (12A). The recirculation loop recirculates the gas contained in the anode circuit or the cathode circuit of the fuel cell, the recirculation circuit comprising a pump (115 or 125) to recirculate the gas. The recirculation circuit comprises a multi-way valve (119 or 129) dividing the circuit into a first section (11R1 or 12R1) and a second section (11R2a or 12R2a), said multi-way valve having: a first stable operating position, the said first stable operating position establishes continuity between the first section and the second section of the circuit; and a second stable operating position which simultaneously interrupts the first section of the recirculation circuit continuity between the first section and the second section, and by moving the multi-way valve, the recirculation circuit is exposed to the atmosphere.

Description

technical field [0001] The present invention relates to fuel cell stacks, more particularly, but not exclusively, to fuel cell stacks of the type having an electrolyte in the form of a polymer membrane (ie PEFC (Polymer Electrolyte Fuel Cell)). Background technique [0002] Fuel cell stacks are known to be able to generate electrical energy directly by electrochemical redox reactions starting from hydrogen (fuel) and oxygen (oxidant), without going through a mechanical energy conversion step. The technology seems promising, especially for motor vehicle applications. A fuel cell stack typically includes a series of individual parts, each consisting essentially of an anode and a cathode separated by a polymer membrane that enables the passage of ions from the anode to the cathode. In the case of a "deadend" line, that is, the line is not normally open at ambient conditions, which is usually the case for the anode circuit, and also for the cathode circuit for batteries operati...

AI Technical Summary

Problems solved by technology

[0004] The object of the present invention is to succeed in providing a close control of gas recirculation and purge, or venting to atmosphere, both of which are necessary, regardless of the stage or state of operation during start-up or extinction. No additional pumps, which are relatively bulky and expensive pieces of equipment

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