High-Throughput Coating Processes for Fuel Cell Bipolar Plates

Proton Exchange Membrane Fuel Cells (PEMFCs) display the highest power densities of any of the fuel cell types, which makes them particularly attractive for transportation & portable applications where minimum size and weight are required. Conventional PEMFCs utilise bipolar plates which are made from graphite (bulky and expensive to machine) or stainless steel. Stainless steel bipolar plates (BPPs), which are dominant in automotive PEMFCs, require a protective coating to achieve the desired performance and lifetime. Hundreds of cells are required within an automotive multi-kW stack, hence it is important to develop coating processes which provide high throughput and economic production of coatings. It is also highly desirable to deposit coatings on metal sheets prior to the forming of bipolar or separator plates, without the coating being adversely affected by the subsequent forming processes. This project will evaluate the feasibility of scale up of high-performance fuel cell BPP coatings in a semi-continuous inline coating deposition equipment, and the effect of scale-up on critical performance characteristics as well as the cost of production of coatings. The effect of scale-up will be evaluated both for coating of pre-formed fuel cell plates and on plates formed post coating, in order to inform decisions on the most appropriate future scale up processes.