The Voltage Uniformity Analysis of High-Power Proton Exchange Membrane Fuel Cell Stack During Cold Start

Abstract

Achieving fast cold startup for high-power proton exchange membrane fuel cell (PEMFC) stacks remains a significant challenge for the commercialization of PEMFC vehicles. The cold start capability of a PEMFC stack is predominantly dictated by the performance of its weakest single cell due to the "Buckets effect," making voltage uniformity a critical factor. In this study, cold start experiments were performed on a 110 kW PEMFC stack comprising 370 cells at -30°C to investigate the impact of stack structure design and cold start parameters on voltage uniformity. The results demonstrate that the side cell adjacent to the negative electrode consistently exhibits superior performance. Moreover, blocking the water chamber of the unipolar plate and fake cell significantly enhances voltage consistency. The study further analyzes the effects of purge duration, coolant flow rate, cathode gas flow rate, and ambient temperature on voltage uniformity. This work provides a comprehensive experimental analysis of voltage uniformity in high-power stacks during cold start and offers valuable insights to guide stack structure design and cold start strategy optimization.

Keywords: high-power PEMFC stack, cold start, voltage uniformity, experimental analysis