Fuel cell subzero cold start remains a central issue prohibiting automotive fuel cell commercialization; however stack level testing is expensive. A quasi-adiabatic single-cell fuel cell fixture was designed, built, and validated to emulate cold starts at the stack level. Galvanostatic cold starts were attempted at 600 mA cm-2; however the tests were dominated by high membrane resistances. To improve controllability, potentiostatic+galvanostatic cold starts were performed: set to 0.1V until the current attained a value of 600 mA cm-2. For the same water content and heater power, potentiostatic tests and galvanostatic tests resulted in comparable cold start profiles. Shorter times to reach 0°C were observed with higher initial water contents (λ=6.2 vs λ=3.2). Heat output data based on cell voltage, current, and heating pad power consumption was input into a finite element model in COMSOL and temperatures predicted by the model were compared to the temperatures measured during the cold starts. cold-start testing is being evaluated using a quasi-adiabatic single cell fixture developed in-house, expanding upon the original proto-type designed at United Technologies Corporation. Heating pads were integrated into the fixture and powered at levels equivalent to 1x and 2x adjacent cells to compensate for non-adiabatic losses. Higher water content favorable impact initial performance, however at long time scales seems to insignificantly impact cold start probability. Cold start probability is significantly impacted by the heating pad condition indicating significance of bipolar plate and coolant thermal mass impact on ability for CL to self-heat to above 0°C.

Quasi-adiabatic proton exchange membrane fuel cell fixture for automotive cold-starts

253rd National Meeting (2017)

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