Toyota Jidosha Kabushiki Kaisha

Takanori Soejima

Ryo Kanada

Hiroshi Hamaguchi

Nobuyasu Haga

A method of estimating a deteriorated state of a battery includes steps Sto SSis a step of obtaining a voltage and a current of the battery a plurality of times for a data acquisition period. Sis a step of calculating an amount of change in current, an amount of change in temperature, and an amount of change in SOC during the data acquisition period. Sis a step of obtaining an allowable amount of change in current, an allowable amount of change in temperature, and an allowable amount of change in SOC based on an average temperature. Sis a step of calculating an impedance component for each frequency bandwidth based on the voltage and the current by subjecting the voltage and the current to Fourier transform when all amounts of change are smaller than the allowable amounts of change.

Method of estimating deteriorated state of secondary battery and secondary battery system

The first step includes performing FFT for a voltage and a current of a battery a plurality of times to thereby calculate the voltage and the current for each frequency. The second step includes determining whether or not the first condition and the second condition are satisfied for the current of the battery that is calculated for each frequency. The third step includes calculating an impedance component of the battery for each frequency range when at least one of the first condition and the second condition is not satisfied, and not calculating the impedance component of the battery for each frequency range when each of the first condition and the second condition is satisfied. The first condition shows that the current in a low frequency range is greater than a reference value. The second condition shows that the current in a frequency range is less than a reference value.

Method of estimating deterioration state of secondary battery and secondary battery system

A method of estimating a deteriorated state of a battery mounted on a vehicle includes first to third steps. The first step is a step of obtaining a voltage value and a current value of the battery a plurality of times during a data acquisition period and storing the values in a memory. The second step is a step of subjecting the voltage value and the current value during the data acquisition period stored in the memory to Fourier transform and calculating an impedance component for each frequency band based on the voltage value and the current value subjected to Fourier transform. The third step is a step of estimating high-rate deterioration of the battery by comparing a ratio E between a medium-frequency impedance ZM and a low-frequency impedance ZLwith a reference value K.

A battery system is configured to be mounted on a vehicle. The battery system includes a secondary battery, a detection device, and an electronic control unit. The electronic control unit is configured to perform communication with an external device that accumulates temperature history data of other vehicle, and is configured to acquire, when the battery temperature of the temperature history data of the vehicle contains an abnormal value, the temperature history data of the other vehicle within a period in which the battery temperature of the temperature history data of the vehicle contains the abnormal value, from the external device, and execute correction of the abnormal value of the battery temperature based on the temperature history data acquired from the external device.

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Toyota, Japan

Takanori Soejima