Spitthoff Lena, Gunnarshaug Astrid Fagertun, Bedeaux Dick, Burheim Odne, Kjelstrup Signe
Department of Energy and Process Engineering, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
PoreLab, Department of Chemistry, Norwegian University of Science and Technology, NO-7491 Trondheim, Norway.
J Chem Phys. 2021 Mar 21;154(11):114705. doi: 10.1063/5.0038168.
A high battery temperature has been shown to be critical for lithium-ion batteries in terms of performance, degradation, and safety. Therefore, a precise knowledge of heat sources and sinks in the battery is essential. We have developed a thermal model for lithium-ion batteries, a model that includes terms not included before, namely, Peltier and Dufour heat effects. The model is derived using non-equilibrium thermodynamics for heterogeneous systems, the only theory which is able to describe in a systematic manner the coupling of heat, mass, and charge transport. The idea of this theory is to deal with surfaces as two-dimensional layers. All electrochemical processes in these layers are defined using excess variables, implying, for instance, that the surface has its own temperature. We show how the Peltier and Dufour heats affect a single cell and may produce an internal temperature rise of 8.5 K in a battery stack with 80 modules. The heat fluxes leaving the cell are also functions of these reversible heat effects. Most of the energy that is dissipated as heat occurs in the electrode surfaces and the electrolyte-filled separator. The analysis shows that better knowledge of experimental data on surface resistances, transport coefficients, and Dufour and Peltier heats is essential for further progress in thermal modeling of this important class of systems.
高电池温度已被证明对锂离子电池的性能、老化和安全性至关重要。因此，精确了解电池中的热源和热阱至关重要。我们开发了一种锂离子电池热模型，该模型包含了以前未包含的项，即珀耳帖热效应和杜福尔热效应。该模型是使用非平衡热力学为非均匀系统推导出来的，这是唯一能够系统地描述热、质量和电荷传输耦合的理论。该理论的思想是将表面视为二维层。这些层中的所有电化学过程都使用过剩变量来定义，这意味着例如表面有其自身的温度。我们展示了珀耳帖热效应和杜福尔热效应如何影响单个电池，并可能在一个由80个模块组成的电池组中产生8.5K的内部温度升高。离开电池的热通量也是这些可逆热效应的函数。作为热量耗散的大部分能量发生在电极表面和充满电解质的隔膜中。分析表明，更好地了解关于表面电阻、传输系数以及杜福尔热效应和珀耳帖热效应的实验数据对于这类重要系统的热建模的进一步进展至关重要。
