Study of three factors for commercial-size PEM fuel cell stack cold start: Manifold, endplate, and assisted heating

Abstract

Numerical investigation on a proton exchange membrane fuel cell stack comprising 400 single cells under subzero temperatures is essential for automotive applications. In this work, a one-dimensional multi-phase PEMFC stack cold start model is built to investigate the effect of manifold configuration and endplates on the cold start process. It is noticed that the U-shape manifold configuration is more conducive to the distribution of reaction gas than the Z-shape, while the Z-shape manifold configuration is more likely to cause damage to the stack due to the dilute oxygen concentration in certain cells. The endplate effect has an important effect on the temperature, ice fraction, and cell voltage of the 20 cells near the endplates. The number of cells affected by the endplate effect is independent of the convective heat transfer coefficient. Finally, the strategy of leveraging the PEMFC stack’s output energy to heat the stack can effectively boost the likelihood of a successful cold start, which can aid the stack achieve a successful cold start at −24℃. The arrangement of two single cells separated by a heating pad provides the best cold start capacity and consistency in the stack.