Lithium ion secondary battery
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsKoji Takahata, Machiko Abe
Life of this patent
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Abstract
A lithium ion secondary battery 100A has negative electrode active material particles 710A which include graphite particles that are at least partially covered by an amorphous carbon film 750. The negative electrode, active material particles 710A have a TG weight-loss-on-heating onset temperature T1 which satisfies the condition 500° C.≦T1≦615° C. and a micro-Raman G-band half-width Gh which satisfies the condition 20≦Gh≦28. This configuration makes it possible to obtain a lithium ion secondary battery 100A in which the reaction resistance in a low-temperature environment can be kept low.
Claims8
A lithium ion secondary battery, comprising:
- negative electrode active material particles comprising graphite particles and being at least partially covered by an amorphous carbon film, wherein,
- the negative electrode active material particles have a TG weight-loss-on-heating onset temperature T1 that satisfies the condition 500° C.≦T1≦615° C. and have a micro-Raman G-band half-width Gh that satisfies the condition 20≦Gh≦28.
A method for manufacturing a lithium ion secondary battery, the method comprising:
- step A of preparing negative electrode active material particles comprising graphite particles that are at least partially covered by an amorphous carbon film, having a TG weight-loss-on-heating onset temperature T1 that satisfies the condition 500° C.≦T1≦615° C., and having a micro-Raman G-band half-width Gh that satisfies the condition 20≦Gh≦28;
- step B of forming a negative electrode mixture of the negative electrode active material particles and a binder mixed together in a solvent;
- and
- step C of coating the negative electrode mixture onto at negative electrode current collector so as to form a negative electrode active material layer on the negative electrode current collector.
Dependencies are inferred from the claim text.