TY - JOUR
T1 - Assessing degradation modes in cylindrical lithium-ion batteries
T2 - A non-invasive method using the entropic heat flow or surface temperature
AU - Kunz, Alexander
AU - Kirst, Cedric
AU - Durdel, Axel
AU - Singer, Jan P.
AU - Jossen, Andreas
N1 - Publisher Copyright:
© 2024 The Authors
PY - 2025/1/30
Y1 - 2025/1/30
N2 - Degradation mode analysis for lithium-ion batteries is typically conducted based on a comparison of potential measurements (PM) between a pristine and aged cell. This publication introduces two methods, either based on heat flow in an isothermal micro-calorimeter (CM) or cell surface temperature (TM). Their feasibility for degradation mode analysis was tested using commercial 18650 LFP/graphite and 21700 NCA/silicon–graphite cells. To reconstruct the entropic coefficient (EnCo) of the pristine and aged full-cell, pristine half-cell EnCos were measured in a micro-calorimeter. These half-cell EnCos were then superimposed to reconstruct the full-cell EnCo from either of the two new methods, CM and TM. The conventional PM-method serves as a validation. The degradation mode results indicate that the proposed methods are possibly more effective for LFP, while providing equivalent results for NCA and graphite electrodes. For silicon–graphite electrodes, an electrode composite model is potentially required. Regarding the measurement of the EnCo itself, the introduced methods significantly reduce measurement time compared to conventional methods, such as potentiometric tracking of entropy change in aging markers. The proposed TM-method might be of interest in applications, as the change in EnCo can be observed by a PT100 temperature sensor, facilitating a non-invasive rapid degradation mode estimation method.
AB - Degradation mode analysis for lithium-ion batteries is typically conducted based on a comparison of potential measurements (PM) between a pristine and aged cell. This publication introduces two methods, either based on heat flow in an isothermal micro-calorimeter (CM) or cell surface temperature (TM). Their feasibility for degradation mode analysis was tested using commercial 18650 LFP/graphite and 21700 NCA/silicon–graphite cells. To reconstruct the entropic coefficient (EnCo) of the pristine and aged full-cell, pristine half-cell EnCos were measured in a micro-calorimeter. These half-cell EnCos were then superimposed to reconstruct the full-cell EnCo from either of the two new methods, CM and TM. The conventional PM-method serves as a validation. The degradation mode results indicate that the proposed methods are possibly more effective for LFP, while providing equivalent results for NCA and graphite electrodes. For silicon–graphite electrodes, an electrode composite model is potentially required. Regarding the measurement of the EnCo itself, the introduced methods significantly reduce measurement time compared to conventional methods, such as potentiometric tracking of entropy change in aging markers. The proposed TM-method might be of interest in applications, as the change in EnCo can be observed by a PT100 temperature sensor, facilitating a non-invasive rapid degradation mode estimation method.
KW - Degradation modes
KW - Entropic coefficient
KW - Isothermal micro-calorimetry
KW - Lithium-ion battery
KW - Non-destructive
KW - State of health
UR - http://www.scopus.com/inward/record.url?scp=85210015744&partnerID=8YFLogxK
U2 - 10.1016/j.jpowsour.2024.235732
DO - 10.1016/j.jpowsour.2024.235732
M3 - Article
AN - SCOPUS:85210015744
SN - 0378-7753
VL - 627
JO - Journal of Power Sources
JF - Journal of Power Sources
M1 - 235732
ER -