Toyota Jidosha Kabushiki Kaisha

Mai Fujiwara

Kenji Takahashi

Ryo Kanada

Yuji Nishi

Yuya Ando

Miki Masumoto

An estimation device configured to estimate a charge rate of a battery includes a voltage sensor configured to detect a voltage of the battery, a temperature sensor configured to detect a temperature of the battery, and a processing circuit. The processing circuit is connected to the voltage sensor and the temperature sensor and is configured to execute, while a vehicle is parked, an estimation process of estimating the charge rate of the battery based on a detection voltage and a detection temperature. The detection voltage is detected by the voltage sensor. The detection temperature is detected by the temperature sensor.

Estimation device

A diagnostic device for a secondary battery having a structure in which positive electrodes and negative electrodes are alternately arranged includes an electronic control unit. The electronic control unit is configured to acquire a first resistance value indicating a magnitude of electrical resistance of the secondary battery, compress at least a part of the secondary battery, acquire a second resistance value indicating a magnitude of electrical resistance of the secondary battery after the compression, determine, using the first and second resistance values, whether an amount of decrease in electrical resistance of the secondary battery by the compression is greater than a predetermined value, and determine whether an increase in resistance due to distortion of at least one of the positive electrodes and the negative electrodes occurs in the secondary battery using a result of the determination.

Diagnostic device for secondary battery and recovery method for secondary battery

A recovery method for a secondary battery having a structure in which positive electrodes and negative electrodes are laminated. The recovery method includes a first compression for compressing at least a part of the secondary battery; a second compression for compressing the secondary battery by applying a load from an outside of the secondary battery when an amount of decrease in electrical resistance of the secondary battery by the first compression is greater than a predetermined value; and a recovery for charging the secondary battery, while the load that compresses the secondary battery is applied to the secondary battery, upon determining that the increase in electrical resistance due to the distortion of at least one of the positive electrodes and the negative electrodes occurs in the secondary battery.

A battery system includes a battery pack including a plurality of cells, and an ECU. The ECU calculates a current distribution in each cell using a ladder circuit network model, the ladder circuit network model being obtained by geometrically modeling an interior of the cell using a plurality of resistance elements and a plurality of power storage elements. The ECU calculates the current distribution in the cell by applying, to the ladder circuit network model, a resistance distribution in the cell calculated based on a salt concentration distribution in the cell.

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Handa, Japan

Mai Fujiwara