(28a) Design and Development of Advanced Automotive Fuel Cell Membranes

Proton exchange membrane fuel cells (PEMFC) have been regarded as one of the most promising power sources for automotive applications. Automotive fuel cell systems have requirements that differ from other fuel cell applications. The challenge is to maintain its high efficiency during dynamic operation over the wide range of operating conditions experienced by the vehicle during its target life. This presentation will review automotive PEMFC system demands, and the design and development strategies for advanced membrane materials.

As one of the most important components of PEMFC, the proton exchange membrane, or PEM, plays a critical role in proton transport, electrical isolation and reactant gas separation. Membrane proton transport resistance is an important factor influencing ohmic loss in fuel cells. Gas crossover leads to fuel efficiency loss and fuel cell material degradation, which in turn increases the cost of vehicle ownership. This presentation will also discuss the performance considerations for PEMs, as well as evaluation methodologies on proton transport resistance, gas crossover as well as fuel cell polarization.

For fuel cell membrane durability consideration, this presentation will focus on development of mechanical support options and the methodology for trading off between mechanical stability and transport (proton, gas, water) properties. It will also discuss fuel cell membrane chemical degradation phenomena induced by impurity contamination, operating conditions, and membrane chemical structure. In addition, this presentation will discuss systematic characterization methods for evaluating membrane mechanical and chemical durability.

Beside the performance and durability discussion on PEMs in fuel cell stack system, this presentation will also discuss membrane cost analysis from point view of fuel cell system production and integration. The presentation will include analysis of fuel cell vehicle cost of ownership as a function of membrane properties such as resistance and gas crossover. Criteria for selection of membrane materials based on proton conductivity, water uptake, gas permeance, chemical stability, mechanical properties and cost will be discussed.