An investigation of characteristic parameter variations of the polarization curve of a proton exchange membrane fuel cell stack under strengthened road vibrating conditions

The characteristic of the polarization curve and the parameter variations of open circuit voltage V0, Tafel slope b and ohmic resistance R in the curve are experimentally investigated through a 150 h strengthened vibration test in this paper, to analyse the steady-state performance of the fuel cell stack under long-term vibrating conditions on strengthened roads. The load spectra applied in the test are simulated by the acceleration signals of the fuel cell stack, which are previously measured in a vehicle vibration test. The load signals of the vehicle vibration test are iterated through a road simulator from vehicle acceleration signals which are originally sampled in the strengthened road of the ground prove. During the test, the current and voltage under steady-state operation of the stack were measured six times at regular intervals. The test results indicate a fluctuating variation of the polarization curves. In the meantime, the V0 decreases by 3% of the original value, R increases by 55.8% and b declines by 28.0%. From the results it can be concluded that the strengthened road vibration exert a significant influence on the steady-state performance of the fuel cell stack, which cannot and should not be ignored during the research.

► The test results indicate a fluctuating variation of the polarization curves. ► The OCV presents a downward trend with the increase of the test duration. ► Tafel slope decreases monotonically to 72.0% of the initial value. ► The ohmic resistance rises linearly and ultimately reaches a growth of 55.8%. ► The strengthened vibration has a great influence on the steady-state performance.