Leakage mechanism model of proton exchange membrane fuel cell sealing structures under vibration conditions

Abstract

ABSTRACT To resolve the issue of predicting the leak rate in proton exchange membrane fuel cells (PEMFCs) under long-term random vibration conditions. Considering the mechanism of bolt vibration loosening and rubber vibration relaxation, a leakage mechanism model of the PEMFC sealing structure under vibration conditions is proposed, and the validity of the model is verified by experimental comparison. The model clearly reveals the quantitative effects of structural parameters and material parameters on the leakage rate of PEMFC under vibration conditions. The research results show that under long-term random vibration conditions, the change of PEMFC leakage rate with time is mainly divided into three stages: response stage, stable stage, and leakage stage. Compared to bolt vibration loosening, the rubber vibration relaxation has a more significant impact on PEMFC leakage, the leakage rate of the fuel cell stack is 433ppm after 10,000 hrs of vibration. In addition, increasing the bolt preload, changing the bolt distribution, reducing surface roughness, and reducing gasket thickness can effectively suppress PEMFC leakage under random vibration conditions, the minimum leakage rate of the fuel cell stack can be reduced to around 170ppm per 10,000 hours. The proposed mechanism model provides an effective method for predicting the leakage rate of PEMFC sealing structures.