In order to pack the largest number of PEM cells into the smallest space for transportation applications, bipolar plate assemblies must be thin. The brittleness of thermoset composites relative to metal poses a practical limit with respect to handling, assembly, and physical strength in the stack environment. A conductive thermoset vinyl ester adhesive-sealant was developed using resin technology from BMC’s 940 bipolar plate composites. Strength and conductivity effects were evaluated along with percent property retention following 2500 hour, 85°C immersion in water and water-glycol solutions. Analysis of variance was employed to assess statistical significance and estimate relative effect size. It was found that flexural strength of bonded specimens exceeded that of solid specimens of equivalent thickness. Its use reduced voltage drop by up to 50% compared with un-bonded specimens. Bonded specimens also showed significant improvement versus solid specimens in retention of properties following immersion. Bonded bipolar assemblies with flow channels showed little change in voltage drop over 2000 hours immersion in water and water-glycol solution at 85°C. These observations suggest the potential to utilize the adhesive to achieve thinner assembly designs with enhanced performance characteristics.

This content is only available via PDF.
You do not currently have access to this content.