Compliant electrical contacts for fuel cell use

Abstract

This invention concerns improvements in fuel cell fabrication. Arrays of independent acting compliant electrical contacts are incorporated within a fuel cell which improve fuel cell Bi Polar Separator Plate (bipolar separator plate) which improve fuel cell operation by creating uniform and intimate electrical contact with the adjacent membrane electrode assembly (Membrane electrode assembly). These compliant electrical contacts provide substantial uniform internal pressure distribution and substantially uniform electrical contact. In one embodiment, the array of compliant electrical contacts are in the form of a plurality of metal springs of various configurations which are electrically and mechanical contacted to a conducting base plate. In another embodiment the array of compliant electrical contacts are in the form of a plurality of small metal pins or rods which are electrically and mechanically contacted to a conducting base plate.

Description

[0001] This application is a continuation-in-part of U.S. Ser. No. 60 / 226,471, filed Aug. 18, 2000 which is incorporated herein by reference in its entirety.[0002] 1. Field of the Invention[0003] This invention concerns compliant electrical contacts for fuel cell use to create, adjust and distribute internal forces and loads to optimize contact area to increase fuel cell performance. In a number of embodiments, an array of metal springs of different shapes and configurations contact the adjacent electrode. In another embodiment, a series of electrical contact points similar to a "bed of nails" is used to adjust forces and pressure.[0004] 2. Description of the Related Art[0005] Fuel cells are energy conversion devices that use hydrogen, the most abundant fuel on earth, and oxygen from the air, to create electricity through a chemical conversion process, without combustion and without harmful emissions. The voltage and current output depends on the number of cells in the stack, total ...

AI Technical Summary

Problems solved by technology

Disassembly and analysis of fuel cell stacks built by traditional and other methods reveals evidence of incomplete electrical contact between bipolar separator plates (BSPs) 8 and the membrane electrode assembly (MEAs) 9, which results in poor electrical conduction, lower cell performance, often along with evidence of gas and liquid leakage.

The assembly of a traditional PEM cell stack which comprises a plurality of PEM cells each having many separate gaskets which must be fitted to or formed on the various components is labor-intensive, costly and in a manner generally unsuited to high volume manufacture due to the multitude of parts and assembly steps required.

The traditional construction method does not allow for testing or evaluation of the individual cells before they are assembled into the stack.

If there is leakage or a performance problem with a single cell or group of cells in an assembled stack, then the entire stack has to be disassembled to correct the problem.

This is very expensive and time consuming.

In another aspect, the plurality of metal springs have an irregular patterned arrangement and substantially non uniform distance between contact points or surfaces.

Images