Toyota Jidosha Kabushiki Kaisha

Kabushiki Kaisha Toyota Chuo Kenkyusho

Yuichi Itou

Chikaaki Okuda

Osamu Hiruta

Hiroshi Sawada

Akira Tsujiko

Yoshio Ukyo

Tomitaro Hara

Sachie Yuasa

Tsuyoshi Sasaki

Mamoru Mizutani

Youji Takeuchi

Takahito Imamine

Hiroki Kondo

Yoshiaki Kikuchi

Motoyoshi Okumura

Tetsuro Kobayashi

Hidehito Matsuo

Yasuhito Kondo

A lithium-ion secondary battery with excellent durability is provided using a two-phase coexisting compound as a positive electrode active material. This lithium-ion secondary battery is provided with an electrode body having a positive electrode containing a positive electrode active material and a negative electrode containing a negative electrode active material, and a non-aqueous electrolyte solution containing a lithium salt in an organic solvent. The positive electrode active material is mainly composed of a two-phase coexisting compound containing lithium, and also contains particles of a lithium-transition metal oxide with a layered structure. The particles of the layered oxide have an average particle diameter of 2 &#x3bc;m or less, and the percentage content thereof in the positive electrode active material is 5 mass % or less.

Non-aqueous electrolyte solution type lithium ion secondary battery

A lithium ion secondary battery provided by the present invention has a positive electrode having a current collector and a positive electrode composite layer provided on the current collector. The current collector contains a metal element A as a main component thereof. The positive electrode composite layer contains a two-phase compound containing lithium as a positive electrode active material. The positive electrode composite layer also contains as an additive a compound having a metal element B, in a composition thereof, that has a higher ionization tendency than the metal element A.

Non-aqueous electrolyte lithium ion secondary battery

The present invention provides a water based lithium secondary battery that can inhibit deteriorations in capacity owing to charge-and-discharge operations and maintain a high capacity even after it is charged and discharged repeatedly. The water based lithium secondary battery includes a positive electrode, a negative electrode, a separatorsandwiched between these, and an aqueous electrolyte solution obtained by dissolving an electrolyte made of a lithium salt in a water based solvent. As the water based solvent, a pH buffer solution is employed. The buffer solution is obtained by dissolving an acid and its conjugate base's salt, a base and its conjugate acid's salt, a salt made from a weak acid and a strong base, a salt made from a weak base and a strong acid, or a salt made from a weak acid and a weak base in water.

Water based lithium secondary battery

A battery characteristic detecting method according to the invention includes a first step in which constant current discharge from a battery is performed at a predetermined current value, and a voltage during constant current discharge is measured; a second step in which overpotential for mass transfer control in the battery or resistance for the mass transfer control in the battery is calculated based on the voltage measured in the first step; and a third step in which a determination that a characteristic change has occurred in the battery is made, when the overpotential for the mass transfer control in the battery or the resistance for the mass transfer control in the battery calculated in the second step is larger than a predetermined threshold value.

Method and device for monitoring deterioration of battery

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Toyota, Japan

Yuichi Itou