In this study, a mathematical model has been developed to simulate the transient cold-start processes of polymer electrolyte fuel cells. The super-cooled water is assumed to exist within the cell. The non-equilibrium water transfer between the membrane and the catalyst layer is considered. The models of water freezing and ice melting in the catalyst layer and gas diffusion layer have been established. For the first time, the randomicity of the freezing process is captured by introducing a freezing probability function. Based on this model, the cold-start processes of a single polymer electrolyte fuel cell starting at various operating and initial conditions have been simulated numerically. The results indicate that the cold-start performance of the cell is determined by the water storage potential of the electrolyte in cathode catalyst layer. For each startup temperature and operating current load, there is a most appropriate initial membrane water content, which corresponds to the longest cell shutdown time. When the cold-start process is failed, the ice is mainly accumulated in the cathode catalyst layer. The ice distribution becomes more non-uniform as the cold-start temperature is lower.

在这项研究中，已经开发了数学模型来模拟聚合物电解质燃料电池的瞬态冷启动过程。假定过冷水存在于电池内。考虑了膜和催化剂层之间的非平衡水转移。建立了催化剂层和气体扩散层中水冻结和冰融化的模型。第一次，通过引入冻结概率函数来捕获冻结过程的随机性。基于该模型，已经数值模拟了在各种操作和初始条件下启动的单个聚合物电解质燃料电池的冷启动过程。结果表明，电池的冷启动性能取决于阴极催化剂层中电解质的储水电位。对于每个启动温度和工作电流负载，都有一个最合适的初始膜含水量，这对应于最长的电池关闭时间。当冷启动过程失败时，冰主要积聚在阴极催化剂层中。随着冷启动温度的降低，冰的分布变得更加不均匀。