Battery state estimation device and battery state estimation method

A battery state estimation device for estimating a temperature of a rechargeable battery, the battery state estimation device comprising:

• an electric charge quantity acquisition unit configured to acquire a charged electric charge quantity of the rechargeable battery;
• an impedance measurement unit configured to measure a plurality of complex impedances of the rechargeable battery by supplying measurement power to the rechargeable battery;
• a parameter calculation unit configured to calculate a parameter that includes a ratio of a difference between measurement angular velocities of two complex impedances in a diffusion region among the measured complex impedances to a difference between components of the two complex impedances;
• and
• a temperature estimation unit configured to estimate a temperature of the rechargeable battery by applying the acquired charged electric charge quantity and the calculated parameter to preset information indicating a relationship between the parameter for the charged electric charge quantity of the rechargeable battery and the temperature of the rechargeable battery.

A battery state estimation method for estimating a charged electric charge quantity of a rechargeable battery, the battery state estimation method comprising:

• measuring a plurality of complex impedances of the rechargeable battery by supplying measurement power to the rechargeable battery;
• calculating a parameter that includes a ratio of a difference between measurement angular velocities of two complex impedances in a diffusion region among the measured complex impedances to a difference between components of the two complex impedances;
• and
• estimating a charged electric charge quantity of the rechargeable battery based on the calculated parameter and preset correlated information between the charged electric charge quantity of the rechargeable battery and the parameter.

A battery state estimation method for estimating a temperature of a rechargeable battery, the battery state estimation method comprising:

• acquiring a charged electric charge quantity of the rechargeable battery;
• measuring a plurality of complex impedances of the rechargeable battery by supplying measurement power to the rechargeable battery;
• calculating a parameter that includes a ratio of a difference between measurement angular velocities of two complex impedances in a diffusion region among the measured complex impedances to a difference between components of the two complex impedances;
• and
• estimating a temperature of the rechargeable battery by applying the acquired charged electric charge quantity and the calculated parameter to preset information indicating a relationship between the parameter for the charged electric charge quantity of the rechargeable battery and a temperature of the rechargeable battery.