Research On The Stiffness And Contact Pressure Of PEMFC Metallic Bipolar Plate

As the key component of proton exchange membrane fuel cell (PEMFC), the performance of bipolar plate will directly affect the output power and battery life of fuel cell. Because of the good electrical and thermal conductivity, high mechanical strength, easy processing and low cost of metallic materials, it becomes the most widely used materials of PEMFC bipolar plate. The stiffness of metallic bipolar plate with punching processed is insufficient, and it vulnerable to the influence of residual stress to warp. It will result in the poor contact between the rib of bipolar plate and gas diffusion layer (GDL) and reduce the performance of fuel cell. Metallic bipolar plate is manufactured by several processes and inevitably has dimension error to accumulate. The dimension error of metallic bipolar plate can affect its contact with GDL. So it is very meaningful to increase the stiffness of metallic bipolar plate and improve its contact with GDL for improve the performance of fuel cell with lower cost.In this paper, a cambered metallic bipolar plate of PEMFC has been proposed. The stiffness and contact with GDL of cambered and general metallic bipolar plate have been compared, then the channel structure and dimensional tolerances have been designed consider the contact between metallic bipolar plate and GDL. The main works in this paper include:By contrast the stiffness of general and cambered metal sheet without channel characteristic used finite element method and experimental verification, it shown that the stiffness and resistance to deformation of cambered metal sheet are higher than general metal sheet without channel characteristic. Similarly, by contrast the stiffness of general and cambered metallic polar plate used FE method, it shown that the cambered structure can help to improve the stiffness and resistance to deformation of metallic bipolar plate.The parameterized finite element models of general and cambered metallic bipolar plate with dimension error contact with GDL have been constructed. By research the contact between metallic bipolar plate and GDL with Monte Carlo simulation method and compared the simulated results of the general metallic bipolar plate and cambered metallic bipolar plate, it indicated that the effect of cambered structure for improve the metallic bipolar plate contact with GDL is not obvious according to the result of two-dimensional FE model.By research metallic bipolar plates with different channel structures contact with GDL and compared them, it indicated that the metallic bipolar plate with less rib fillet radius, less width ratio of rib and channel, and slanting channel side wall have better contact with GDL. At the same time, to meet the contact conditions, the maximum allowed processing dimension error of metallic bipolar plates with different channel structures has been determined.The results of this paper provide a new idea for optimize the structure of the metallic bipolar plate in order to improve its performance and provide a method and basis for the channel structures and dimension tolerances design.