Abstract
Due to the complexities and changes in operating conditions, the impact of dynamic load on the vehicle fuel cell engine has attracted much attention. Dynamic response of fuel cell affects the performance and life of the battery on a certain extent. And it is one of the obstacles to commercialization. This paper aims to study the dynamic response characteristics of proton exchange membrane fuel cell in dynamic load change. In this paper, the dynamic response characteristics of proton exchange membrane fuel cell were studied by means of transient test method and theoretical analysis. The internal response of the proton exchange membrane fuel cell was analyzed by theoretical analysis combined with air oxygen comparison test and dynamic response characteristics under different oxygen concentration Elaborated. The main research contents were as follows. When the air or oxygen was tested in low gas stoichiometric ratio 1.2 at the same time, the air high current density area obviously occurred transient gas shortage, and the negative of lowest voltage value also occurred. The undershoot of oxygen almost did no increase with the increases of current density step, and maintained at 0.03V. And the response time increased between 0.02s-0.3s. However, in the air test, the undershoot and response time showed a significant increase in linear with the increase of current step, and the value of undershoot was in 0.03v-0.45v, and the response time was in 0.1s-20s. When the air and oxygen flow rate was same, then the undershoot value of oxygen still maintained in 0.03v. But excessive oxygen damaged the battery water balance, resulting in a significant increase in response time. With the increase of oxygen concentration, the dynamic response was low and the response time decreased linearly. So that the dynamic response was mainly caused by mass transfer.
