Storage battery control device, power storage system, control method, and computer-readable medium
A storage battery control device includes: a voltage measurement means for measuring terminal voltage of a storage battery; a current measurement means for measuring charge current and discharge current of the storage battery; a capacity calculation means for calculating a cumulative capacity of the storage battery by using the charge current measured by a current measurement unit; a control means for determining an operation of the storage battery, based on at least one of the terminal voltage, the charge current, the discharge current, and the cumulative capacity; and a charging/discharging control means for causing the storage battery to operate in accordance with an instruction from the control means, and the charging/discharging control means causes the storage battery to charge by a first charging method from a discharge end voltage to a first charge voltage, to charge by a second charging method at the first charge voltage, to charge by the first charging method from the first charge voltage to a second charge voltage, and to charge by the second charging method at the second charge voltage.
1. A storage battery control device comprising:
a voltage measurement unit which measures terminal voltage of a storage battery;
a current measurement unit which measures charge current and discharge current of the storage battery;
a capacity calculation unit which calculates a cumulative capacity of the storage battery by using the charge current measured by the current measurement unit;
a control unit which determines an operation of the storage battery, based on at least one of the terminal voltage, the charge current, the discharge current, and the cumulative capacity; and
a charging/discharging control unit which causes the storage battery to operate in accordance with an instruction from the control unit, wherein
the charging/discharging control unit causes the storage battery
to charge by a first charging method from a discharge end voltage to a first charge voltage,
to charge by a second charging method at the first charge voltage,
to charge by the first charging method from the first charge voltage to a second charge voltage, and
to charge by the second charging method at the second charge voltage, wherein
the control unit calculates a full charge capacity of the storage battery by using the cumulative capacity measured by the capacity measurement unit,
the control unit calculates a differential capacity between a cumulative capacity obtained until the first charge voltage is reached, and a cumulative capacity obtained until the second charge voltage is reached, and
the control unit calculates the full charge capacity, based on the differential capacity and a variation of a charging rate from the first charge voltage to the second charge voltage.
2. The storage battery control device according to claim 1 , wherein the charging/discharging control unit determines to switch from the second charging method to the first charging method, based on the charge current of the storage battery.
3. The storage battery control device according to claim 1 , wherein the control unit
determines to switch from the second charging method to the first charging method, based on a period in which charging is performed by the second charging method.
4. The storage battery control device according to claim 1 , wherein the first charge voltage is a voltage corresponding to a capacity higher than a discharge lower-limit capacity set by a user of the storage battery.
5. The storage battery control device according to claim 1 , wherein the control unit corrects the full charge capacity in accordance with a charging rate of a storage battery at the discharge end voltage.
6. The storage battery control device according to claim 1 , wherein the capacity measurement unit calculates a cumulative capacity obtained until the first charge voltage is reached and a cumulative capacity obtained until the second charge voltage is reached.
7. A power storage system comprising:
a storage battery including a plurality of secondary cells;
a voltage measurement unit which measures voltage of the storage battery;
a current measurement unit which measures charge current and discharge current of the storage battery;
a capacity calculation unit which calculates a cumulative capacity of the storage battery by using the charge current measured by the current measurement unit;
a control unit which determines an operation of the storage battery, based on at least one of the terminal voltage, the charge current, the discharge current, and the cumulative capacity; and
a charging/discharging control unit which controls power of the storage battery, based on an instruction from the control unit, wherein
the charging/discharging control unit causes the storage battery
to charge by a first charging method from a discharge end voltage to a first charge voltage,
to charge by a second charging method at the first charge voltage,
to charge by the first charging method from the first charge voltage to a second charge voltage, and
to charge by the second charging method at the second charge voltage, wherein
the control unit calculates a full charge capacity of the storage battery by using the cumulative capacity measured by the capacity measurement unit,
the control unit calculates a differential capacity between a cumulative capacity obtained until the first charge voltage is reached, and a cumulative capacity obtained until the second charge voltage is reached, and
the control unit calculates the full charge capacity, based on the differential capacity and a variation of a charging rate from the first charge voltage to the second charge voltage.
8. A control method for controlling charging and discharging of a storage battery, comprising:
measuring terminal voltage of the storage battery;
measuring charge current and discharge current of the storage battery;
calculating a cumulative capacity of the storage battery by using the charge current;
determining an operation of the storage battery, based on at least one of the terminal voltage, the charge current, the discharge current, and the cumulative capacity; and
controlling power of the storage battery, based on the determined operation of the storage battery, wherein
the control of power of the storage battery includes:
causing to charge by a first charging method from a discharge end voltage to a first charge voltage;
to charge by a second charging method at the first charge voltage;
to charge by the first charging method from the first charge voltage to a second charge voltage; and
to charge by the second charging method at the second charge voltage,
wherein determining an operation of the storage battery comprises:
calculating a full charge capacity of the storage battery by using the cumulative capacity that has been measured,
calculating a differential capacity between a cumulative capacity obtained until the first charge voltage is reached, and a cumulative capacity obtained until the second charge voltage is reached, and
calculating the full charge capacity, based on the differential capacity and a variation of a charging rate from the first charge voltage to the second charge voltage.