Paper Title
Evaluating Dimensional Error Effect of Metallic Bipolar Platesinshort Stack Pem Fuel Cell using Finite Element Simulation

In recent years, development of polymer electrolyte membrane fuel cells (PEMFCs) has been considered to generate clean power for automotive and portable applications. One of the main components of PEMFC is bipolar plate (BPP) that has a significant influence on cost and performance of the system. Metallic BPPs produced via thin sheet forming, have been received broad attentions as alternative to conventional graphite BPPs because of advantages such as relatively low cost, high mechanical strength, good thermal conductivity and high power density. Distribution of contact pressure between BPP and membrane electrode assembly (MEA) considerably affect the performance of PEMFC stack. However, due to the flexibility of thin metal sheets and spring back in forming process, dimensional errors are inevitable and lead to inappropriate distribution of contact pressure between BPPs and MEAs, resulting in a decrease of fuel cell performance. On the other hand, excessive accuracy in manufacturing of BPPs leads to increase the final cost of PEMFC. In order to reduce unnecessary costs, management of design process and improve the efficiency, evaluating dimensional error effect of metallic BPPs on the performance of short stack PEMFC is done using finite element method. First, a parametric finite element model of short stack PEMFC consist of metallic BPPs and MEAs assembly is developed and heights of BPP ribs are fully parameterized due to the dimensional errors. Then, different combinations of dimensional errors are randomly applied to the BPP ribs and the MEA contact pressure distributions are calculated via finite element analysis. Finally, the relation between dimensional tolerances of BPP ribs and MEA pressure distribution is presented to prevent the electrical resistance losses inside the cell. The results of this study can be used to determine suitable dimensional tolerances of BPPs according to engineering requirements and are helpful to guide the production process of short stack PEMFCs with metallic BPPs. Keywords- Short Stackpemfc, Metallic Bipolar Plate, Dimensional Tolerance, Finite Element Analysis