Modeling and Experimental Investigation of a Thermocell Based on a Polymer-membrane With Two Hydrogen Electrodes

这个项目应用的目的是热电化学发电机，所谓的热电池的实验和理论研究。这里考虑的热电池的构造类似于聚合物电解质燃料电池，其中阳极被冷却到低（环境）温度并且阴极被加热。在两个电极处，提供湿润的氢气（不同温度）用于加热和冷却。这些氢并没有被全部消耗，但是质子从阳极迁移到阴极。在初步研究中，这种PEM热电池的基本功能可以被证明是作为热电发电机。与众所周知的半导体型热电发电机相反，这种热电池的具体特征是低工作温度（<100°C）和中等驱动温差（<50 K）。当对这种电化学能量转换器建模时，必须考虑强耦合的传输机制，特别是在电解质中。该模型是一种基于不可逆过程热力学的非平衡态方法，可以系统地描述耦合输运过程。该模型方法所需的唯象系数将通过实验装置来测量。该装置还将用于测量作为阳极和阴极之间的温差的函数以及作为氢的水分的函数的热电池的电流-电压特性。在经过验证的模型的帮助下，可以估计这种能量转换装置的整体潜力，并可以为后续项目设计具有封闭氢循环的第一个原型。

The aim of this project application is the experimental and theoretical investigation of a thermoelectrochemical generator, a so called thermocell. The thermocell considered here is constructed similar to a polymer electrolyte fuel cell, in which the anode is cooled to low (ambient) temperatures and the cathode is heated. At both electrodes moistened hydrogen (different temperatures) is provided for heating and cooling. This hydrogen is not consumed in total, but protons migrate from the anode to the cathode. In preliminary investigations, the basic functionality of this PEM thermocell could be proven to function as a thermoelectric generator. The specific features of this thermocell are, contrary to the well-known semiconductor type thermoelectric generator, a low operating temperature (<100°C) and moderate driving temperature differences (≃50K).When modeling this electrochemical energy converter, strongly coupled transport mechanisms must be considered, especially in the electrolyte. The proposed model is a non-equilibrium approach based on the thermodynamics of irreversible processes (TiP), with which coupled transport processes can be described systematically. The phenomenological coefficients required for this model approach are to be measured by means of the experimental setup. The setup will also be used to measure the current-voltage characteristics of the thermocell as a function of the temperature difference between anode and cathode and as a function of moisture of the hydrogen. With the help of the validated model, the overall potential of this energy conversion device can be estimated, and a first prototype with a closed hydrogen cycle could be designed for follow-up projects.