Neutron imaging for automotive polymer electrolyte fuel cells during rapid cold starts.

The phase transition from supercooled water to ice is closely related to the electrochemical performance and lifetime of an energy device at sub-zero temperatures. In particular, fuel cells for passenger cars face this issue because they are frequently started and stopped under sub-zero conditions during the winter season. However, there is a lack of visual information regarding the processes that occur within the fuel cell stack, and insight into how to improve the safety and performance during cold starts is lacking. In this study, we developed an operando neutron imaging system to visualise the water distribution inside an automotive single cell simulating a fuel cell stack during cold starts. This was achieved using a rapid heating unit. In addition, we showcased cold-start tests at three different sub-zero temperatures, and the obtained results suggest that pre-conditioning residual water and post-cold-start meltwater have an impact on the rapid cold-start performance.