Battery control device

1. A battery control device which includes an internal resistance computation unit configured to calculate an internal resistance value of a battery, and controls charging and discharging of the battery on the basis of the internal resistance value calculated by the internal resistance computation unit, comprising:

an index computation unit which calculates an index indicating a polarization voltage of the battery; and

a determination unit which determines whether the index is equal to or more than a determination threshold,

wherein, when the determination unit determines that the index is equal to or more than the determination threshold, the charging and discharging of the battery are controlled on the basis of a previously determined internal resistance value calculated when the index was less than the determination threshold.

2. The battery control device according to claim 1 ,

wherein the index computation unit calculates a polarization voltage calculation value as the index on the basis of at least one of a voltage and a temperature of the battery, and a current flowing to the battery.

3. The battery control device according to claim 1 ,

wherein the index computation unit calculates a value obtained by time-sequentially averaging a current flowing to the battery as the index.

4. The battery control device according to claim 1 ,

wherein the index computation unit calculates an energizing time of the battery as the index.

5. The battery control device according to claim 1 ,

wherein the index computation unit calculates at least two of a first index which is a polarization voltage calculation value calculated on the basis of a voltage and a temperature of the battery, and a current flowing to the battery, a second index which is a value obtained by time-sequentially averaging the current flowing to the battery, and a third index which is an energizing time of the battery, and

the determination unit determines whether each index calculated by the index computation unit is equal to or more than each determination threshold which is set for each index.

6. The battery control device according to claim 2 ,

wherein, when the determination unit determines that the index is equal to or more than the determination threshold in a non-energizing time before the battery starts to be energized, the battery after the energizing starts is controlled on the basis of the internal resistance value calculated when the index is less than the determination threshold before the determination.

7. The battery control device according to claim 1 ,

wherein the internal resistance computation unit calculates the internal resistance value on the basis of a difference between two charging states of different calculation methods.

8. The battery control device according to claim 7 ,

wherein one of the two charging states is a charging state in which the internal resistance value is calculated on the basis of an open circuit voltage of the battery.

9. The battery control device according to claim 1 ,

wherein the internal resistance computation unit calculates the internal resistance value on the basis of a difference between a closed circuit voltage measurement value of the battery and a closed circuit voltage calculation value calculated on the basis of a current flowing to the battery.

10. The battery control device according to claim 1 ,

wherein the determination threshold is set according to a temperature of the battery and/or a deterioration of the battery.