Degradation reactions in SONY-type Li-ion batteries
Thermal instabilities were identified in SONY-type lithium-ion cells and correlated with interactions of cell constituents and reaction products. Three temperature regions of interaction were identified and associated with the state of charge (degree of Li intercalation) of the cell. Anodes were shown to undergo exothermic reactions as low as 100 C involving the solid electrolyte interface (SEI) layer and the LiPF{sub 6} salt in the electrolyte (EC:PC:DEC/LiPF{sub 6}). These reactions could account for the thermal runaway observed in these cells beginning at 100 C. Exothermic reactions were also observed in the 200 C--300 C region between the intercalated lithium anodes, the LiPF{sub 6} salt, and the PVDF. These reactions were followed by a high-temperature reaction region, 300 C--400 C, also involving the PVDF binder and the intercalated lithium anodes. The solvent was not directly involved in these reactions but served as a moderator and transport medium. Cathode exothermic reactions with the PVDF binder were observed above 200 C and increased with the state of charge (decreasing Li content). This offers an explanation for the observed lower thermal runaway temperatures for charged cells.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (US)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 20086877
- Resource Relation:
- Conference: 1999 Materials Research Society Spring Meeting, San Francisco, CA (US), 04/05/1999--04/08/1999; Other Information: PBD: 2000; Related Information: In: New materials for batteries and fuel cells. Materials Research Society symposium proceedings, Volume 575, by Doughty, D.H.; Nazar, L.F.; Arakawa, Masayasu; Brack, H.P.; Naoi, Katsuhiko [eds.], 454 pages.
- Country of Publication:
- United States
- Language:
- English
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