Toyota Jidosha Kabushiki Kaisha

Satomi Uchida

Shinobu Okayama

(A) A first lithium-ion battery is prepared. (B) A capacity loss of the first lithium-ion battery is detected. (C) Capacity restoration treatment is performed on the first lithium-ion battery having a detected capacity loss to produce a second lithium-ion battery. The first lithium-ion battery includes at least a positive electrode, a negative electrode, and an electrolyte solution. The electrolyte solution contains a lithium salt, a solvent, and an additive in advance of the detecting a capacity loss. The additive has an oxidation potential. The oxidation potential is higher than an OCP of the positive electrode in the first lithium-ion battery having a state of charge of 100%. The capacity restoration treatment involves charging the first lithium-ion battery in such a way that at least part of the additive is oxidized.

Lithium-ion battery containing electrolyte including capacity restoration additives and method for restoring capacity of lithium-ion battery

Provided is a method by which the degraded performance of a lithium ion secondary battery containing phosphorus atoms (P) in a nonaqueous electrolytic solution can be restored by subjecting the lithium ion secondary battery in which a coating film including P is formed on a positive electrode surface, to a comparatively simple treatment. The degraded performance recovery method for a lithium ion secondary battery disclosed herein includes an ultrasound treatment step of applying ultrasound to the lithium ion secondary battery. In the ultrasound treatment step, the frequency of the generated ultrasound is 900 kHz or higher, and the period of time in which the ultrasound is applied to the lithium ion secondary battery continuously is 5 min or more.

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Okazaki, Japan

Satomi Uchida