Study on internal dynamic response during cold start of proton exchange membrane fuel cell with parallel and serpentine flow fields

A deeper understanding of the internal dynamics and transient phenomena during cold start of proton exchange membrane fuel cell (PEMFC) is essential to inspire better strategies. In this study, segmented fuel cell technology is applied to capture the internal current and temperature evolution during cold start of PEMFC. It is found that the effect of flow field on cold start performance is less important than that under normal temperature. The single-channeled serpentine (SS) flow field exhibits the fastest response rate and better cold start performance owing to its high pressure drop and excellent drainage ability. The flow field does not affect the overall evolution trend, but the response rate increases with the pressure drop. During successful cold start, the maximum current density first appears in the downstream of the cathode, then it moves upwards to the middle and inlet region. However, during failed cold start, the current density gradually decreases while moving upstream due to blockage. Besides, severe performance degradation occurs after failed cold start. The degradation of the SS flow field is significantly greater than the others, indicating that a rapid response and superior cold start performance may increase the chance of degradation once the cold start fails.