Toyota Jidosha Kabushiki Kaisha

Keiko Wasada

Akira Tsujiko

Tomitaro Hara

Sachie Yuasa

Takeshi Abe

Daisuke Teramoto

Takuichi Arai

Yohei Shindo

Tsuyoshi Yano

Machiko Abe

An object is to provide a method of charging and maintaining a lithium ion secondary battery which method is capable of preventing a decrease in the capacity of the battery. Another object is to provide a battery system capable of preventing a decrease in battery capacity, and a vehicle and a battery-mounted device which have such a battery system mounted therein. A method of charging and maintaining lithium ion secondary batteriesusing positive active material particlesmade from a two-phase coexistence type positive active material PM in a positive electrode plateincludes an overcharge step Sfor charging the lithium ion secondary batteries to bring their SOC (State of Charge) SC into an overcharge SOC not higher than 100% but higher than a target SOC, a return discharge step Sfor discharging, after the overcharge step, the lithium ion secondary batteries to make their SOC equal to the target SOC, and a maintaining step S

Method of charging and maintaining lithium ion secondary battery, battery system, vehicle and battery-mounted device

The lithium secondary battery positive electrode provided by the present invention has a positive electrode collector and a positive active material layer formed on the collector. The positive active material layer is composed of a matrix phase containing at least one particulate positive active material and at least one binder, and an aggregate phase dispersed in the matrix phase, constituted by aggregation of at least one particulate positive active material and containing substantially no binder.

Lithium secondary battery and positive electrode for the battery

Provided is a lithium-ion secondary battery having an excellent initial capacity as well as a good capacity retention rate. The battery comprises a positive electrode comprising a positive electrode active material, a negative electrode comprising a negative electrode active material, and a non-aqueous liquid electrolyte. The negative electrode active material comprises a graphitic material that satisfies each of the following properties: (a) in its Raman spectrum obtained by Raman scattering analysis using an exciting light at a wavelength of 532 nm, having a ratio of its D-peak intensity Ito its G-peak intensity I, an R value (I/I), of 0.15 or smaller; and (b) having a full width at half maximum of the G peak, &#x394;v, of 23 cmor smaller. The secondary battery has a capacity retention rate of 70% or greater when subjected to 500 cycles of charging and discharging at a constant current rate of 2 C at 60&#xb0; C.

Lithium ion secondary battery

Provided is a secondary battery system which can accurately detect a state of a secondary battery system (such as a secondary battery state and a secondary battery system failure). The secondary battery system () includes dV/dQ calculation means which calculates a dV/dQ value as a ratio of a change amount dV of a battery voltage V of a secondary battery () against a change amount dQ of an accumulation amount Q when the accumulation amount Q of the secondary battery () is changed. The secondary battery system () detects the state of the secondary battery system () by using the dV/dQ value.

Secondary battery system

A battery control system controls an external charging unit in a vehicle including a vehicle body, engine, motors, secondary battery, and the external charging unit, and includes a degradation detecting unit that detects degradation of the secondary battery, during charging of the second battery by the external charging unit.

Battery control system and vehicle

A control method for a lithium ion secondary battery includes performing a charging step of charging the lithium ion secondary battery with a predetermined quantity of electricity when the battery voltage of the lithium ion secondary battery has decreased to a lower limit battery voltage that is set at a value that falls within a range higher than (B&#x2212;C) V and lower than or equal to (B&#x2212;C+0.2) V where a maximum value of a positive electrode potential of a flat portion in a discharge positive electrode potential curve is B (V) and a negative electrode dissolution potential is C (V). It is possible to suppress a dissolution of a negative electrode current collector of the lithium ion secondary battery to prevent the service life of the lithium ion secondary battery from shortening because of an internal short circuit.

Control method for lithium ion secondary battery, and lithium ion secondary battery system

The invention provides a method of diagnosing a malfunction in an abnormal voltage detecting apparatus, which includes breaking an electrical connection between a secondary battery () and an abnormal voltage detecting apparatus () and connecting the abnormal voltage detecting apparatus to a direct current voltage generating portion () that is different from the secondary battery (), applying direct current voltage that has a predetermined voltage value that is outside of a normal voltage range to the abnormal voltage detecting apparatus () using the direct current voltage generating portion, and determining that there is a malfunction in the abnormal voltage detecting apparatus if the abnormal voltage detecting apparatus does not determine that the voltage is abnormal.

Growing community of inventors

Toyota, Japan

Keiko Wasada