Simulation and Analysis of Downward Bowing Problem on Automotive PEMFC Stacks Based on the Equivalent Beam Model

Abstract:

This study focuses on the complex computation and difficult convergence of whole fuel cell stack based on the finite element simulation models for automotive applications. It represents a method of equivalent modelling to simplify the flow channel and sealing part of a unit cell into uniform anisotropic materials for the flow channel of bipolar plates which is achieved by calculating the equivalent stiffness. Furthermore， the equivalent beam model of the fuel cell stack is established through the difference in the mechanical properties of the beam structure. The downward bowing mechanism of the fuel cell stacks for vehicles subjected to impact is analyzed， and an equivalent model of the fuel cell stacks containing multiple unit cells is established. Based on this model， impact simulation is carried out， and the different numbers of unit cells in the stack， the impact acceleration， assembly force of the fuel cell stack， and the thickness of the end plate are systematically analyzed in order to evaluate their influence on the downward bowing of the fuel cell stack subjected to impact of the vehicle on road. Research shows that more unit cells and greater impact acceleration lead to more pronounced downward bowing. Appropriately increasing the encapsulation force and improving the end plate shape can reduce the degree of downward bowing in the stack.