Water content is one of the most significant internal states which affects the performance and durability of proton exchange membrane fuel cells (PEMFCs). However, water content inside fuel cells is difficult to be directly measured. This study aims at developing a new method to fast estimate the water content inside fuel cells. We investigated the relationship between water content and the exhaust back pressure of fuel cells, which indicated that the exhaust back pressure is positively correlated with exhaust water concentration. Then, a two-step algorithm was proposed to estimate water content inside fuel cells. Finally, this algorithm was validated by high frequency resistance experiments. This new estimation method can calculate water content inside fuel cells quickly and is important in developing real-time control strategy.
Keywords PEM fuel cells, water content, state estimation, exhaust back pressure, online algorithm