Experimental investigations of ageing of commercial BEV Li-ion batteries
Licentiate thesis, 2023
In the compiled works, results from extensive testing on discharge current frequency, variation in SOC level and temperature are reported for cells with mixed material negative electrodes (Graphite/ SiOx ). Unexpected trends where cycling in low SOC causes more rapid degradation than cycling in high SOC are observed. The capacity retention after 1200 FCE was 84.7% for cells cycled in 5-15% SOC, whereas for cells cycled in 45-55% SOC the capacity retention after 1200 FCE was 94.7%. This dependency is shown to be stronger than the temperature dependency for mixed material negative electrodes. It is also demonstrated that dynamic current profiles affect the capacity retention with a strong correlation for frequencies below 100 mHz.
The ageing processes involved are analysed using various in situ electrochemical characterisation techniques and post-mortem investigations. The strong SOC dependency is shown to be largely attributed to ageing of SiOx in mixed material electrodes, with LAMSiOx contributing to a loss of 7% of
overall capacity in 5-15% SOC cycling, compared to only 3% in 85-95% SOC cycling. For 0-50% SOC cycling in 45°C temperature, capacity retention of
SiOx had dropped to ∼ 25 % of initial capacity, whereas graphite capacity was still in excess of 90% of initial capacity.
silicon oxide
lithium plating
ageing
Physics-based modelling
Electric Vehicles
Lithium Ion Batteries
lifetime
NCA
State of Charge
Author
Kristian Bartholdsson Frenander
Chalmers, Electrical Engineering, Electric Power Engineering
K. Frenander, T. Thiringer, Low Frequency Influence on Degradation of Commercial Li-ion Battery
N. Roy Chowdhury, A.J. Smith, K. Frenander, A. Mikheenkova, R. Wreland Lindström, T. Thiringer, The State of Charge Dependence of Degradation in Lithium-ion Cells From a Tesla Model 3
A. Mikheenkova, A.J. Smith, K. Frenander, Y. Tesfamhret, N. Roy Chowdhury, C.W. Tai, T. Thiringer, R. Wreland Lindström, M. Hahlin, M.J. Lacey, Ageing of High Energy Density Automotive Li-ion Batteries: The Effect of Temperature And State-of-Charge
Ageing phenomena coupled to dynamic cycling of automotive Li-ion batteries
Swedish Energy Agency (2018-018491), 2019-08-30 -- 2023-11-30.
Driving Forces
Sustainable development
Areas of Advance
Transport
Subject Categories
Other Chemical Engineering
Vehicle Engineering
Other Electrical Engineering, Electronic Engineering, Information Engineering
Publisher
Chalmers