Arrhenius plots for Li-ion battery ageing as a function of temperature, C-rate, and ageing state – An experimental study

We present an extensive analysis of Li-ion battery ageing via Arrhenius plots. The V-shaped Arrhenius plots show minima at an optimum temperature corresponding to the longest cycle-life. The V-shape of the Arrhenius plots signifies the crossover between the two dominating ageing mechanisms – solid electrolyte interphase (SEI) growth in the high temperature range and lithium deposition in the low temperature range. Subjects of our investigations are commercial 5 Ah high energy 21,700-type cells with LiNi0.90Co0.05Al0.05O2 + LiNiO2 (NCA + LNO) cathode and Si/graphite anode (∼3% Si) and 0.1 Ah lab-made pouch cells with LiNi1/3Mn1/3Co1/3O2 (NMC111) cathode and a graphite anode. The results of the Arrhenius plots are analysed in the context of C-rate, cell ageing, and electrode properties. We find that the crossover between the dominating ageing mechanism and hence the optimum operating temperature of the Li-ion cells depend on C-rate, anode coating thickness/particles sizes, the state of health, and the shape of the capacity fade curve. Considering the change of the dominant ageing mechanism can help designing battery systems with longer service life. Additionally, we show a lifetime estimation for temperature dependent cycling of batteries emphasizing the merit of Arrhenius plots in the context of battery cell ageing.