(Best Presentation Award - 1st Place) Cyclic Aging Study of Commercial Li-Ion Batteries Focusing on Temperature

Abstract

It is well known that temperature significantly impacts the cyclic aging behavior of Lithium-ion batteries. Temperatures outside the recommended optimum range promote different aging mechanisms. However, the temperature dependency of these aging mechanisms might also vary for different cell chemistries used in commercial Li-ion battery cells. Additionally, due to heat generation inside the cell and the cooling strategies in the applications the temperature field inside the cell is most likely inhomogeneous. This has led to several cyclic aging studies looking into these non-homogeneous temperature fields [1–4]. Hunt et al.[4] observed more pronounced aging for surface cooled cells, which they attributed to through-plane thermal gradients. Werner et al.[1,2] found no acceleration of the aging behavior for the applied in-plane thermal gradients compared to homogeneously aged cells. For thermal transients both Werner et al.[1,2] and Carter et al.[3] found faster aging in some cases.Few cyclic aging studies have been done on the impact of more complex temperature boundary conditions. These studies involved very few cell chemistries and more research is needed. A test was set up and preliminary results of a cyclic aging study on commercial Lithium-ion battery cells can be presented. Multiple parameters, such as capacity and resistance, are evaluated and compared to reference cells, which are cycled at a standard, homogeneous temperature. Werner et al. (2020) Inhomogeneous Temperature Distribution Affecting the Cyclic Aging of Li-Ion Cells. Part I: Experimental Investigation. Batteries 6:13. https://doi.org/10.3390/batteries6010013Werner et al. (2020) Inhomogeneous Temperature Distribution Affecting the Cyclic Aging of Li-Ion Cells. Part II: Analysis and Correlation. Batteries 6:12. https://doi.org/10.3390/batteries6010012Carter et al. (2019) Detection of Lithium Plating During Thermally Transient Charging of Li-Ion Batteries. Front Energy Res 7. https://doi.org/10.3389/fenrg.2019.00144Hunt et al. (2016) Surface Cooling Causes Accelerated Degradation Compared to Tab Cooling for Lithium-Ion Pouch Cells. J Electrochem Soc 163:A1846-A1852. https://doi.org/10.1149/2.0361609jes