Design of PEMFC bipolar plate cooling flow field based on fractal theory

During the operation of the proton exchange membrane fuel cell (PEMFC), the chemical reaction yields a large amount of heat. Long-term operation may cause local overheating problems which damage the proton exchange membrane structure, pull down the fuel cell performance drastically. Aiming at improving the temperature distribution and cooling capacity of PEMFC, a novel tree-shaped fractal fuel cell bipolar plate cooling flow field is proposed. The polarization curve, current density distribution, maximum temperature, temperature uniformity, cooling hydraulic pressure drop and the water content of proton exchange membrane are investigated for the fractal cooling flow field with different number of dimensions. The results show that the tree-shaped fractal cooling flow field can achieve better distributions of coolant and temperature uniformity than parallel cooling flow field. The maximum temperature reduces from 340.7 K to 337.8 K, and temperature uniformity index reduces from 1.47 to 0.45, respectively. Compared with the serpentine cooling flow field, the tree-shaped fractal cooling flow field effectively solves the problem of excessive cooling pressure drop and reduces the parasitic power loss while ensuring efficient cooling performance. This novel cooling flow field design offers an excellent solution to solve the local overheating of PEMFC.