The Study of effective parameters in hydroforming of fuel cell metallic bipolar plates with parallel serpentine flow field

Bipolar plates are the most important and expensive components used in fuel cells. Metallic bipolar plates are the best choice to replace graphite or machined thick metal plates due to their lightweight and low cost. Selection of suitable forming process is one of the main subjects in fuel cell technology. Nowadays، hydroforming process is commonly used for the production of metallic bipolar plates because of its capability in forming light weight and complex parts. Among the various patterns of bipolar plates، serpentine flow field pattern inevitably brings two main defects of rupture of material during forming process and uneven flow distribution in practical operations. In this research، forming of a slotted interdigitated serpentine pattern on SS304 stainless steel sheet by hydroforming process has been examined using finite element simulation and experimental approach. The effects of process parameters and die geometry on the thickness distribution and filling percent are also studied. It is concluded that by increasing the forming pressure، filling percent of the die increases and the thickness of critical region is more reduced due to the increasing of drawing ratio. Also، it was found that hydroforming process has high repeatability.