Numerical investigation of high-temperature PEMFC thermal management using pyrolytic graphite

Good heat dissipation to reduce the inside temperature difference can help prolong the lifetime of high temperature proton exchange membrane fuel cells (HT-PEMFCs). This study presents a thermal management method based on a heat spreader composed of pyrolytic graphite and copper for a HT-PEMFC. First, the feasibility of using pyrolytic graphite for HT-PEMFC heat dissipation is evaluated using the heat balance model. Then, a threedimensional single cell model is coupled with heat transfer, mass transfer and electrochemical reactions to simulate the HT-PEMFC operation with the heat spreader thermal dissipation. The model is used to investigate the effect of various heat spreader structures composed of two kinds of pyrolytic graphite and the operating voltage on the temperature distribution and current density distribution. Finally, the HT-PEMFC with this thermal management method is compared with oil cooling. The results show that the TPG (thermal pyrolytic graphite) provides better HT-PEMFC heat dissipation than the PGS (pyrolytic graphite sheet). The heat can be dissipated from both sides to further reduce the temperature difference in the membrane electrode assembly (MEA) by 64.7 % over that with single-side heat dissipation. In addition, the TPG heat dissipation improves the current density uniformity to almost the same as that of oil cooling with the TPG giving a lower temperature difference of less than 5 K. The parasitic power with the TPG heat dissipation is 9.5 % less and the stack volume and weight are 14.2 % and 2 % less than with oil heat dissipation with a temperature difference of 10 K in the MEA.