Cell Heat Generation and Dissipation: From Experimentation to Application for Cell Design.

Abstract

Lithium ion batteries (LIBs) are increasingly important in ensuring sustainable mobility and reliable energy supply, storing and managing energy from renewable sources [1]. Temperature is a critical factor in LIBs performance optimisation where large temperature deviations within the cell could lead to accelerated degradation and in extreme cases, thermal runaway. Thermal management has therefore become the focus of intensive research in an attempt to improve battery performance and lifespan [2-5]. Despite the growing research interest in this area, cell heat generation and heat dissipation pathways are not usually considered when designing a cell. This typically leads to cells with thermal bottlenecks prone to internal thermal gradients. With the goal of improving performance and lifetime, a two-dimensional electro-thermal model has been developed to simulate cell performance and internal states under complex thermal boundary conditions [6]. This model can be used to assess different cooling strategies and parameters such us tab position and dimensions can be optimised from the thermal performance perspective for a particular cell chemistry and geometry. In this study, a novel experimental procedure is employed to evaluate cell heat generation and dissipation for various operation conditions. The two-dimensional electro-thermal model was employed to assess the internal temperature distribution during the measurements and to verify the heat dissipation patterns observed during the experiments. As a result, a new metric, the Cell Cooling Coefficient (CCC) is proposed to evaluate the thermal pathways of a cell cooled via its tabs. International Energy Agency. Tracking Clean Energy Progress 2017. 1–82 (2017). doi:10.1787/energy_tech-2014-enBandhauer, T. M., Garimella, S. & Fuller, T. F. A Critical Review of Thermal Issues in Lithium-Ion Batteries. J. Electrochem. Soc. 158, R1–R25 (2011).Troxler, Y., Wu, B., Marinescu, M., Yufit, V., Patel, Y., Marquis, J.A., Brandon, N.P. & Offer, G. J. The effect of thermal gradients on the performance of lithium-ion batteries. J. Power Sources 247, 1018–1025 (2014).Hunt, I. A., Zhao, Y., Patel, Y. & Offer, G. J. Surface Cooling Causes Accelerated Degradation Compared to Tab Cooling for Lithium-Ion Pouch Cells. J. Electrochem. Soc. 163, A1846–A1852 (2016).Khan, M. R., Swierczynski, M. J. & Kær, S. K. Towards an Ultimate Battery Thermal Management System : A Review. (2017). Batteries 3, 9 (2017)Zhao, Y., Patel, Y., Zhang, T. & Offer, G. J. Modeling the Effects of Thermal Gradients Induced by Tab and Surface Cooling on Lithium Ion Cell Performance. J. Electrochem. Soc. 165, A3169–A3178 (2018).