Stress-induced Ageing of Lithium-Ion Batteries
Keywords:Electrochemical impedance spectroscopy, Li-ion batteries, Microscopy, Stress cycles
AbstractLithium-ion batteries are well established for use in portable consumer products and are increasingly used in high power electro-mobility and photovoltaic storage applications. In hybrid and plug-in electric vehicles degradation and useful lifetime at standard operation conditions are critical parameters in addition to performance and safety. Here stress-induced ageing of commercially available high power battery cells of the type A123 AHR32113M1 Ultra-B, consisting of a LiFePO4 cathode and a graphite anode have been investigated. A usually accepted capacity loss for electric vehicles of 20% was reached after 8560 stress profiles corresponding to a driving distance of almost 200'000 km. Cycling with a stress profile applying constant power corresponding to the average power and energy of a full stress profile and starting at 60% state of charge showed a much faster capacity loss. Electric impedance measurements show the dependence of the capacity loss and constant phase element at low frequency, indicating Li-ion diffusion blocking in the cathode. Microscopic analysis of anode, separator, and cathode, shows defect formation in bulk material and at interfaces.
How to Cite
M. Held, U. Sennhauser, Chimia 2015, 69, 737, DOI: 10.2533/chimia.2015.737.
Copyright (c) 2015 Swiss Chemical Society
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