Bipolar plates for PEM fuel cells - a basic approach for competitive fuel cell components

摘要

Recent years have seen major advances in the development of PEM fuel cell technology as an automotive propulsion system, driven by rising oil prices, stricter emission controls, and increasing electrical energy requirements in motor vehicles. PEM fuel cells can also be used as auxiliary power units (APU), i.e. as an electricity source in conventional propulsion vehicles. One of the main components of the fuel cell stack is the bipolar plate, which performs the function of supplying and removing the reaction media, conducting the electrical current, and individual cell cooling. Bipolar plates may be made of formed metal, injection-molded carbon composite, or milled hard graphite. The requirements for low costs, good cold-start performance, and compact size are met particularly well by metallic bipolar plates. This paper outlines the significance of the bipolar plate as a core component of the fuel cell stack, compares the opportunities and limitations of various bipolar plate technologies, and provides an overview of the potential, and design freedoms and constraints, offered by metallic bipolar plates as the likely technology of the future. The second part describes design solutions for practical implementation.