| CPC G01R 31/392 (2019.01) | 13 Claims |

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1. A battery deterioration diagnosis device that performs deterioration diagnosis of a battery, the device comprising:
charge/discharge circuitry to charge or discharge the battery;
charge/discharge control circuitry to control the charge/discharge circuitry in such a way that the battery is charged or discharged after a temperature of the battery rises to a predetermined diagnosis temperature;
a current-voltage detector to detect current and voltage of the battery during a period in which the battery is charged or discharged by the charge/discharge control circuitry;
differential voltage calculation circuitry to calculate a differential value of the voltage of the battery as a differential voltage on a basis of the current and voltage detected by the current-voltage detector; and
deterioration state estimation circuitry to estimate a deterioration state of the battery on a basis of a change in the differential voltage calculated by the differential voltage calculation circuitry, wherein
the higher the diagnosis temperature, the larger the current during charging or discharging of the battery by the charge/discharge control circuitry.
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