Design Improvements on a Bipolar Plate With Passive Water Management Using the Biomimetic Design Method

Liquid water build up in the cathode flow channels of a polymer electrolyte membrane fuel cell (PEMFC) can limit performance. A mechanism that removes accumulating liquid water continuously from the flow channels is required. While a number of water management strategies have been demonstrated, the search for improvements continues. This paper describes a novel technique of using biomimetic design to systematically generate a passive water management system concept for PEMFCs. Studies have shown that biology is a good source of analogies for engineering design. We believe that biomimetic design is an effective design methodology for PEMFC designs due to several common characteristics of biological systems, such as efficient use of material and energy, a self-regulating characteristic, and high tolerance to a wide range of operating conditions. A passive water management solution was generated based on two biological phenomena identified using the biomimetic design method. The biological phenomena inspired use of design elements such as random abrasions and polyethersulfone strands to remove water from the flow channels. The design was demonstrated on a simple test apparatus with low air flow rates and low inlet pressure. Preliminary experiments with the test apparatus have shown total recovery from flow channel catastrophic flooding within seconds. The present paper discusses the biomimetic design process, implementation, and prototype results.