The performance of miniature metallic PEM fuel cells

A prototype of metallic PEM fuel cell with thin stainless steel bipolar plates was tested for their potential applications in portable electronic products. The flow field pattern was grown from the stainless steel plates by the electroforming process. The main flow channel has the dimensions of 300 mu m (width) x 300 mu m (depth). The dimensions of the micro-features were 100 mu m width x 50 mu m depth and 50 mu m width x 50 mu m depth. The material of the electroformed flow field pattern is nickel. A prototype of a single cell with total thickness of 2.6 mm, overall reaction area of 4cm(2) and bipolar plate area of 16 cm(2) was assembled for this study. In order to improve its corrosion resistance, the bipolar plates were coated with 5 mu m thick of multi-layered corrosion resistant material. In this study, indices of cell performance, with and without micro-features, of flow field concentration distribution, water-draining capability were studied by both numerical simulation and experimental measurement. The results show that the micro-features will provide a more uniform gas concentration environment in the bipolar plate flow field. Also, the bipolar plate with micro-features could greatly improve cell-draining capability. The results of cell performance tests show that the cell average power density reaches 195 mW cm(-2). The long-term tests verify their performance are very stable. (C) 2006 Elsevier B.V. All rights reserved.