Stainless steel bipolar plates with rectangular micro channels by additive manufacturing: Effect channel width on fuel cell performance

Stainless steel bipolar plates (BPs) fabricated using innovative additive manufacturing techniques can improve fuel cell performance and reduce costs. A high current density can be obtained using a low-cost membrane electrode assembly (MEA) with low platinum (Pt) loading at the anode, along with BPs with rectangular micro channels. Three types of BPs of serpentine flow field are designed after varying the width of the rectangular channel. Two types of MEAs are used. First is 0.12 mg cm⁻² Pt loading at anode, and the second is 0.50 mg cm⁻². Wherein MEA with Pt loading at 0.12 mg cm⁻² is used, a high current density is obtained as the channel width decreases. The BP with 300 µm channels has a current density of 1.205 A cm⁻², which is higher by 31.4% than that of BP with 500 µm channels and higher by 70.2% than that of the BP with 940 µm channels. However, when the MEA with Pt loading at 0.50 mg cm⁻² is applied to the test, the opposite results are obtained: As the channel width becomes narrow, the current density decreases. In the long-term operation, a similar trend in the current density as that of the short-term operation is observed.