Flow fields for supporting fluid diffusion layers in fuel cells

The present invention relates to fluid flow fields for fuel cells. More particularly, it relates to flow field designs for supporting structurally weak and/or mechanically anisotropic fluid diffusion layers in solid polymer electrolyte fuel cells. An improved flow field design for a flow field plate comprises fluid distribution channels having an average width W and separated by landings in which the channels are configured such that unsupported rectangular surfaces of length L and width W on an adjacent fluid diffusion layer have a ratio L/W less than about 3. Improved support may be obtained for instance by using sinusoidally shaped channels. Certain fluid diffusion layer embodiments offer desirable characteristics (for example, low cost, thickness) for use in fuel cells but may also be undesirably weak mechanically and consequently will benefit from improved mechanical support from adjacent flow field plates comprising the present flow field design.