A novel multi-step investigation of in-plane heterogeneity for commercial-size fuel cells based on current distribution model and multi-point impedance method

[Display omitted] •In-plane heterogeneity is a critical factor influencing lifetime of commercial fuel cell.•Comprehensively heterogeneity evaluation method with three steps is proposed.•Rapid heterogeneity assessment is conducted by the multi-point monitoring method.•Current and voltage redistribution process is revealed by a novelty-four-chamber model.•Correlation between heterogeneity and polarization loss is quantified by multipoint EIS method. A novel evaluation methodology for comprehensively analyzing the in-plane heterogeneity in commercial-size fuel cells is developed. First, the multi-point voltage monitoring method is applied to judge heterogeneity rapidly. Then, the current and voltage redistribution mechanism is analyzed by an advanced model and in-situ temperature measurement to give a qualitative evaluation. Finally, a novel multi-point impedance method is proposed to characteristic the polarization loss at different regions of fuel cells and give a quantitative assessment of the heterogeneity. Additionally, the Pearson correlation between the voltage difference and polarization parameters is quantified. The results indicate that the local polarization loss differences are influenced by the species distribution and manifest as a non-negligible voltage difference in the bipolar plate. The local current density and the voltage obtained in the corresponding position show a strong negative correlation with a correlation parameter of −0.9231. In addition, a robust correlation between the voltage difference and the in-plane polarization resistance difference is revealed. This work provides a comprehensive framework for analyzing complex internal heterogeneity in fuel cells, revealing high potential in applications.