Decoupling the thermal and non-thermal effects of discharge C-rate on the capacity fade of lithium-ion batteries

• Published in: Journal of power sources Vol. 510; p. 230390
• Main Authors: Xu, Bin, Diao, Weiping, Wen, Guangrui, Choe, Song-Yul, Kim, Jonghoon, Pecht, Michael
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 31.10.2021
• Subjects: Capacity fade; Discharge C-Rate; Li-ion battery; Non-thermal effect; Thermal effect; Non-thermal effect; Thermal effect; Capacity fade; Li-ion battery; Discharge C-Rate
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2021.230390

In battery-powered electronic devices, an increase in the discharge C-rate is expected when using functions that require more power. Temperature rise is the thermal effect of discharge C-rate due to ohmic heating, causing lithium-ion batteries to degrade faster. There are also non-thermal effects, such as increased mechanical stress on electrode particles and structure. How much each of the thermal and non-thermal effects contributes to the capacity fade is valuable for understanding the discharge C-rate-related degradation mechanisms in lithium-ion batteries. This paper decouples the thermal and non-thermal effects of discharge C-rate on the capacity fade of lithium-ion batteries. Pouch cells are subject to continuous charge-discharge cycling under six testing conditions. Two stress factors are investigated: discharge C-rate (0.5C, 1.75C, and 3C) and temperature control (constant battery surface temperature at 45 °C and constant ambient temperature at 45 °C). The capacity degradation mechanisms associated with thermal and non-thermal effects of discharge C-rate is revealed using cycling data, impedance measurement, incremental capacity analysis, and scanning electron microscopy/energy dispersive X-ray spectroscopy analysis. A capacity fade model is developed as the function of discharge C-rate and cycle numbers. The contributions of the thermal and non-thermal effects at different discharge C-rates on the capacity loss are quantified. •Customized a PID-controlled heating system.•Decoupled the thermal and non-thermal effects of discharge C-rate.•Investigated the battery capacity fade under the effects of discharge C-rate.•Quantified the contributions of the thermal and non-thermal effects.