SECONDARY BATTERY CHARGE CONTROL METHOD AND CHARGE CONTROL CIRCUIT

• US 20100213901A1
• Filed: 10/03/2008
• Published: 08/26/2010
• Est. Priority Date: 10/05/2007
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Morimoto, Naohisa, Inoue, Toshihiro
• Granted Patent: US 8,350,531 B2
• Time in Patent Office: Days
• US Class Current: 320/145
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 8/003 Converting light into electric energy, e.g. by using photo-voltaic systems
• CPC Class Codes: H01M 10/44 Methods for charging or discharging circuits for charging H02J7/00
• CPC Class Codes: H01M 10/46 Accumulators structurally combined with charging apparatus circuits for charging H02J7/00
• CPC Class Codes: H02J 7/00712 the cycle being controlled or terminated in response to electric parameters
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

A secondary battery charge control method includes: a charge control step of executing charging by supplying a charge current to a secondary battery; a charge information acquisition step of acquiring information relating to the charging executed in the charge control step; a storage step of storing the information acquired in the charge information acquisition step as charge data; and a charge inhibition determination step of determining whether to inhibit the charging in the charge control step on the basis of the charge data of a previous cycle that have been stored in the storage step when charging in the charge control step is started again after charging in the charge control step has been completed.

Claims

1. A secondary battery charge control method comprising:

a charge control step of executing charging by supplying a charge current to a secondary battery;

a charge information acquisition step of acquiring information relating to the charging executed in the charge control step;

a storage step of storing the information acquired in the charge information acquisition step as charge data; and

a charge inhibition determination step of determining whether to inhibit the charging in the charge control step on the basis of the charge data of a previous cycle that have been stored in the storage step when charging in the charge control step is started again after charging in the charge control step has been completed.

2. The secondary battery charge control method according to claim 1, wherein

the charge information acquisition step includes a timing step of measuring a charge time from start to end of the charging in the charge control step;

the storage step includes storing a charge time measured in the timing step as the charge data, and

the charge inhibition determination step includes inhibiting the charging in the charge control step when a charge time of a previous cycle that has been stored as charge data in the storage step exceeds a charge time that has been preset to be equal to or longer than a time necessary to charge fully the secondary battery in the charge control step from a state with an SOC of 0%.

3. The secondary battery charge control method according to claim 1, wherein

the charge information acquisition step includes a temperature detection step of detecting a temperature of the secondary battery in the charge period in the charge control step,

the storage step includes storing the temperature detected in the temperature detection step as the charge data, and

the charge inhibition determination step includes inhibiting the charging in the charge control step when a temperature of a previous cycle that has been stored as the charge data in the storage step exceeds a determination temperature that has been preset as a temperature at which the secondary battery is at risk of deterioration.

4. The secondary battery charge control method according to claim 1, wherein

the charge information acquisition step includes an SOC calculation step of calculating an SOC of the secondary battery,

the storage step includes storing the SOC of the secondary battery that has been calculated in the SOC calculation step as the charge data when the charging in the charge control step ends, and

the charge inhibition determination step includes inhibiting charging in the charge control step when the SOC stored as the charge data in the storage step at the time the previous charge has ended exceeds a determination value that has been set as an upper limit value of an SOC range that can be attained by the secondary battery in a normal state.

5. The secondary battery charge control method according to claim 1, wherein

the charge information acquisition step includes a voltage detection step of detecting a terminal voltage of the secondary battery during the charge period in the charge control step,

the storage step includes storing the terminal voltage that has been detected in the voltage detection step as the charge data, and

the charge inhibition determination step includes inhibiting the charging in the charge control step when a charge highest voltage that is a highest value of a terminal voltage in a charge period of a previous cycle exceeds a determination voltage preset as a voltage at which the secondary battery is at risk of deterioration, on the basis of a terminal voltage stored as the charge data in the storage step.

6. The secondary battery charge control method according to claim 1, wherein

the charge control step includes charging the secondary battery by supplying a constant charge current to the secondary battery, and forming a pulse charge current by stopping and supplying the charge current, the charge control step includes stopping the supply of the charge current when a terminal voltage of the secondary battery becomes equal to or higher than an upper limit voltage that has been set to a voltage higher than an open circuit voltage at a time the secondary battery is fully charged, and supplying the charge current when the terminal voltage of the secondary battery becomes equal to or lower than a lower limit voltage that has been set to be equal to or higher than an open circuit voltage at a time the secondary battery is fully charged.

7. The secondary battery charge control method according to claim 1, wherein the secondary battery is a lithium secondary battery.

8. A charge control circuit comprising:

a charge control unit that executes charging by supplying a charge current to a secondary battery;

a charge information acquisition unit that acquires information relating to the charging executed by the charge control unit,

a storage unit that stores the information acquired by the charge information acquisition unit as charge data, and

a charge inhibition determination unit that determines whether to inhibit the charging by the charge control unit on the basis of the charge data of a previous cycle that have been stored in the storage unit when charging by the charge control unit is started again after charging by the charge control unit has been completed.

9. The charge control circuit according to claim 8, wherein

the charge information acquisition unit includes a timing unit that measures a charge time from start to end of the charging by the charge control unit;

the storage unit stores a charge time measured by the timing unit as the charge data, and

the charge inhibition determination unit inhibits the charging by the charge control unit when a charge time of a previous cycle that has been stored as the charge data in the storage unit exceeds a charge time that has been preset to be equal to or longer than a time necessary to charge fully the secondary battery by the charge control unit from a state with an SOC of 0%.

10. The charge control circuit according to claim 8, wherein

the charge information acquisition unit includes a temperature detection unit that detects a temperature of the secondary battery in the charge period of the charge control unit,

the storage unit stores the temperature detected by the temperature detection unit as the charge data, and

the charge inhibition determination unit inhibits the charging by the charge control unit when a temperature of a previous cycle that has been stored as the charge data in the storage unit exceeds a determination temperature that has been preset as a temperature at which the secondary battery is at risk of deterioration.

11. The charge control circuit according to claim 8, wherein

the charge information acquisition unit includes an SOC calculation unit that calculates an SOC of the secondary battery,

the storage unit stores an SOC of the secondary battery that has been calculated in the SOC calculation unit as the charge data when the charging by the charge control unit has ended, and

the charge inhibition determination unit inhibits the charging in the charge control unit when the SOC stored as the charge data in the storage unit at the time the previous charge has ended exceeds a determination value that has been set as an upper limit value of an SOC range that can be attained by the secondary battery in a normal state.

12. The charge control circuit according to claim 8, wherein

the charge information acquisition unit includes a voltage detection unit that detects a terminal voltage of the secondary battery during the charge period by the charge control unit;

the storage unit stores a terminal voltage that has been detected by the voltage detection unit as the charge data, and

the charge inhibition determination unit inhibits the charging in the charge control unit when a charge highest voltage that is a highest value of a terminal voltage in a charge period of a previous cycle exceeds a determination voltage that has been preset as a voltage at which the secondary battery is at risk of deterioration, on the basis of a terminal voltage stored as the charge data in the storage unit.

13. The charge control circuit according to claim 8, wherein

the charge control unit charges the secondary battery by supplying a constant charge current to the secondary battery, and forming a pulse charge current by stopping and supplying the charge current, the charge control unit stopping the supply of the charge current when a terminal voltage of the secondary battery becomes equal to or higher than an upper limit voltage that has been set to a voltage higher than an open circuit voltage at a time the secondary battery is fully charged, and supplying the charge current when the terminal voltage of the secondary battery becomes equal to or lower than a lower limit voltage that has been set to be equal to or higher than an open circuit voltage at a time the secondary battery is fully charged.

14. The charge control circuit according to claim 8, wherein the secondary battery is a lithium secondary battery.

15. A charge control circuit comprising:

a charge control unit that executes charging by supplying a charge current to a secondary battery, the charge control unit charging the secondary battery by supplying a constant charge current to the secondary battery, and forming a pulse charge current by stopping and supplying the charge current, the charge control unit stopping the supply of the charge current when a terminal voltage of the secondary battery becomes equal to or higher than an upper limit voltage that has been set to a voltage higher than an open circuit voltage at a time the secondary battery is fully charged, and supplying the charge current when the terminal voltage of the secondary battery becomes equal to or lower than a lower limit voltage that has been set to be equal to or higher than an open circuit voltage at a time the secondary battery is fully charged;

a charge information acquisition unit that acquires information relating to the charging executed by the charge control unit, the charge information acquisition unit including;

a timing unit that measures a charge time from start to end of the charging by the charge control unit, a temperature detection unit that detects a temperature of the secondary battery in the charge period of the charge control unit, an SOC calculation unit that calculates an SOC of the secondary battery, and a voltage detection unit that detects a terminal voltage of the secondary battery during the charge period by the charge control unit;

a storage unit that stores the information acquired by the charge information acquisition unit as charge data, the storage unit storing a charge time measured by the timing unit as the charge data, the temperature detected by the temperature detection unit as the charge data, an SOC of the secondary battery that has been calculated in the SOC calculation unit as the charge data when the charging by the charge control unit has ended, and a terminal voltage that has been detected by the voltage detection unit as the charge data; and

a charge inhibition determination unit that determines whether to inhibit the charging by the charge control unit on the basis of the charge data of a previous cycle that have been stored in the storage unit when charging by the charge control unit is started again after charging by the charge control unit has been completed, the charge inhibition determination unit inhibiting the charging by the charge control unit when a charge time of a previous cycle that has been stored as the charge data in the storage unit exceeds a charge time that has been preset to be equal to or longer than a time necessary to charge fully the secondary battery by the charge control unit from a state with an SOC of 0%, or when a temperature of a previous cycle that has been stored as the charge data in the storage unit exceeds a determination temperature that has been preset as a temperature at which the secondary battery is at risk of deterioration, or when the SOC stored as the charge data in the storage unit at the time the previous charge has ended exceeds a determination value that has been set as an upper limit value of an SOC range that can be attained by the secondary battery in a normal state, or when a charge highest voltage that is a highest value of a terminal voltage in a charge period of a previous cycle exceeds a determination voltage that has been preset as a voltage at which the secondary battery is at risk of deterioration, on the basis of a terminal voltage stored as the charge data in the storage unit.