Water and thermal management of PEM fuel cell stack.

摘要

A water and thermal management model for a Ballard PEM fuel cell stack has been developed to investigate its performance in this thesis. A general calculation methodology has been developed to implement this model. Knowing a set of gas feeding conditions (i.e., pressure, temperature, flow rate) and stack physical conditions (i.e., channel geometry, heat transfer coefficients, operating current), the model will provide information regarding the reaction products (i.e., water and heat), stack power, stack temperature and system efficiency, thereby assisting the designer in achieving the best thermal and water management. Furthermore, if the stack undergoes a perturbation, such as the initial start-up, quick change in current, or a shutdown, the model could predict the dynamic information regarding stack temperature, cell voltage, and power as a function of time.; The issues of two-phase, two-component flow heat transfer and pressure drop along the channel are discussed in this thesis. The performance and efficiency of air compressors and cooling pumps are also considered for the reason of system analysis. By considering all the practical operating parameters mentioned above, this model will provide the optimal stack design pattern and the best working condition, which achieve maximum system efficiency.