The endplate plays an important role in the performance and durability of fuel cell stacks, and also to mass power density. Aiming at a lightweight endplate and uniform deflection of the endplate, the purpose of this study is to model the endplate including the supply, discharge ports and the distribution manifolds. The stress and displacement distribution of the endplate are also analyzed by numerical simulation. After that, the three optimized topologies aiming to minimize compliance, uniform stress distribution and two objectives coupling are discussed, and the intake endplate and blind endplate are individually reconstructed. The mass of optimized intake endplate is reduced by 35%, and the mass of optimized blind endplate is reduced by 46% for the goal of attaining a lightweight endplate, while maintaining the uniformity of the stress distribution of the first cell next to the endplate. Considering these factors, optimized endplates are obtained, which are valuable to fuel cell stack design.

The contact pressure between bipolar plates (BPPs) and a membrane electrode assembly (MEA) has a key impact on Proton Exchange Membrane Fuel Cell (PEMFC) performance. However, it is difficult to obtain the contact pressure combined with operating temperature action via the finite element analysis (FEA) model, resulting in limited calculation resources for the problem of multiscale and thermo-mechanical coupled action in a full-dimensional fuel cell stack. This paper establishes an equivalent stiffness model for contact pressure, which could be predicted simply and quickly compared with the FEA model. Then, this presented model is validated by experimentation with a full-dimensional fuel cell stack assembled with 10 cells using pressure-sensitive film. The error between the presented model and the experimentation of the full-dimensional stack is a maximum of 4.41%. This work provides important insight into thermo-mechanical coupled action, as less empirical testing is required to identify the contact pressure in a full-dimensional fuel cell stack.

The deflection of the endplate under the clamping force has a vital effect on fuel cell performance. An optimal cross-sectional shape with a high moment of inertia of the endplate is significant to maximize the bending stiffness of the fuel cell stack. Five cross-sectional shapes (rectangular, round, parabolic, rectangular + round, and rectangular + parabolic) of the typical endplates are proposed. An analytical study on the moments of inertia of the endplates is introduced and analyzed. The maximum moments of inertia of the cross-sections are obtained and displayed in a matrix in thickness and length. The statistical results show that the “rectangular + parabolic” cross-section has the advantage of wide dimensional size while maintaining a high moment of inertia. Finally, the analytical studies are validated by a finite element method (FEM) and the corresponding trends are highly agreed upon. The maximum moment of inertia of the parabolic endplate is 85.71% higher than the rectangular endplate with a thickness of 80 mm, and the corresponding contact pressure variance is 6.15% less than the rectangular endplate. The presented analytical study is significant and effective to optimize the cross-sectional shape of the endplate and provide an endplate design direction for a large fuel cell stack.