In this work, a state-of-the-art, full-scale, Proton Exchange Membrane (PEM) electrolysis cell model is presented. The developed three-dimensional (3D) model accounts for compressible, two-phase flow including species, heat and charge transport in the anode and membrane. By incorporating electrochemistry as well as detailed heat and two-phase flow transport phenomena, the model is capable of studying cells at full-scale and for high current densities with high accuracy. To enable the modeling of thin catalyst layers (CL) for high current density operation in a 3D framework, the CL is modeled as an interfacial boundary.

The necessary electrochemical parameters are obtained by fitting polarization curves of a two-dimensional version of the devised model to experimental measurements from a small cell. It is found that the obtained parameters are in agreement with literature values and that the fitted model is able to capture the performance for temperatures from 323 to 353 K and for current densities up to 5 A cm⁻². Furthermore, it is identified that for high current density operation, three types of overpotential losses are nearly equally dominant: the anode kinetics, the PEM ohmic resistance and the non-membrane ohmic resistance due to poor electrical contact between layers and current constrictions in the CL.

The developed 3D model is applied to three different circular, interdigitated anode flow fields aimed a high pressure and high current density operation. When operating the cell at a cathode pressure of 100 bar, a current density of 5 A cm⁻² and stoichiometric constant of 350, it is found that the cell potential shows little dependence on the applied flow field. However, large in-plane variations can occur that may impact lifetime significantly. Particularly for the temperature field, an in-plane difference of up to 20.2 K relative to the intended cell temperature is found in the worst case. For all three cases, the occurrence of hot spots is linked to the maldistribution of two-phase flow and current density. Out of the studied cases, it was found that equal land width between the channels gives the best distribution of charge, mass and heat.

在这项工作中，提出了一种最先进的全尺寸质子交换膜（PEM）电解池模型。开发的三维（3D）模型考虑了可压缩的两相流，包括物种，阳极和膜中的热和电荷传输。通过结合电化学以及详细的热和两相流传输现象，该模型能够全面研究细胞，并以高准确度研究高电流密度。为了能够在3D框架中对高电流密度操作的薄催化剂层（CL）进行建模，将CL建模为界面边界。

通过将设计模型的二维版本的极化曲线拟合到小电池的实验测量值，可以获得必要的电化学参数。发现所获得的参数与文献值一致，并且拟合模型能够捕获在从323到353 K的温度和对于高达5 A cm ^-2的电流密度下的性能。此外，可以确定的是，对于高电流密度操作，三种类型的过电势损耗几乎同等重要：阳极动力学，PEM欧姆电阻和由于层之间的不良电接触和CL中的电流收缩而引起的非膜欧姆电阻。

所开发的3D模型应用于针对高压和高电流密度操作的三种不同的圆形，相互交叉的阳极流场。当电池在100 bar的阴极压力下运行时，电流密度为5 A cm ^-2且化学计量常数为350，发现电池电势几乎不依赖于所施加的流场。但是，可能会发生较大的面内变化，从而可能严重影响使用寿命。特别是对于温度场，在最坏的情况下，相对于目标电池温度的面内差异最大为20.2K。对于这三种情况，热点的出现都与两相流和电流密度的分布不均有关。在所研究的案例中，发现通道之间的相等的焊盘宽度可提供最佳的电荷，质量和热量分布。