Promising Metal Separator Plate Materials and Coatings for PEM Fuel Cells

摘要

For large scale introduction of PEM fuel cells into the automotive market it is of paramount importance that separator plates are low in cost, weight, volume and contact resistance but high in corrosion resistance. They should show operational lifetimes exceeding 5,000 hours spread over much longer time periods. Separator plate materials currently under review in industry are either graphite- (e.g. graphite composite) or metal-based. With its expertise as a steel manufacturer in combination with extensive coating & plating knowledge, it was a natural step for Corus to start researching metal separator plates for PEM fuel cell applications. This research has mostly been conducted in joint projects with others such as Energy research Centre of the Netherlands (ECN). The work not only entailed developing metal coatings and substrates but was combined with research into suitable forming techniques to meet the stringent requirements set by the automotive industry. The separator plate research has been in progress for 10 years and this paper will provide an overview of promising results obtained. We have developed a very promising coating combining high corrosion resistance with a low contact resistance for the cathode side of a low temperature PEMFC. For the anode side an uncoated substrate has been found. The suitability of both materials has been determined through in-situ testing at ECN in a joint cooperation. In addition work is being done on another newly developed coating which is evaluated as well in this paper. Development of new materials requires extensive testing. Obviously in-situ testing is most favourable but also quite expensive and time consuming to undertake. We therefore needed a quick and simple screening test. An ex-situ test has been developed at Corus which typically takes approximately 16 hours (overnight) and requires no complicated equipment. Results of both ex-situ and in-situ testing will be shown and compared.