State of charge calculation device and state of charge calculation method

• US 20030097225A1
• Filed: 10/31/2002
• Published: 05/22/2003
• Est. Priority Date: 11/16/2001
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Teruo, Ishishita
• Granted Patent: US 6,845,332 B2
• Time in Patent Office: Days
• US Class Current: 702/63
• CPC Class Codes: G01R 31/006 on road vehicles, e.g. automobiles or trucks testing of ignition installations peculiar to internal combustion engines F02P17/00
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements

Abstract

A state of charge calculation device includes an ammeter for detecting charge and discharge currents of a secondary battery, a state detection sensor for detecting a start time of discharge from the secondary battery to an engine, a battery electronic control unit (ECU) for calculating a state of charge of the secondary battery. The battery ECU of this state of charge calculation device calculates the state of charge of the secondary battery, based on the current and voltage detected at the time when discharge starts.

Claims

1. A state of charge calculation device that calculates a state of charge of a secondary battery connected to a load, comprising:

a current detection portion that detects a charge and discharge currents of the secondary battery; and

a voltage detection portion that detects voltage of the secondary battery;

a discharge start time detection portion that detects a time of a start of discharge from the secondary battery to the load; and

a controller that calculates the state of charge of the secondary battery, based on the detected currents and the detected voltage, using a method that corresponds with the time of the start of the discharge.

2. The state of charge calculation device according to claim 1, wherein

the discharge start time detection portion detects the time of the start of discharge to the load, based on one of the detected currents and the detected voltage.

3. The state of charge calculation device according to claim 1, further comprising:

an information storage portion that stores information necessary to accomplish two or more methods used in calculation of the state of charge of the secondary battery; and

a method selection portion that selects, from among the two or more stored methods, the method that corresponds with the time of the start of the discharge, wherein

the controller calculates the state of charge of the secondary battery based on the detected currents and the detected voltage, using the selected method.

4. The state of charge calculation device according to claim 1, further comprising:

a storage portion that stores two or more parameters calculated in advance based on a characteristic value of the secondary battery; and

a selection portion that selects, from among the two or more stored parameters, a parameter that corresponds with the time detected by the discharge start time detection portion, wherein

the controller calculates the state of charge of the secondary battery based on the detected currents and the detected voltage using the method corresponding to the calculating method using the selected parameter.

5. The state of charge calculation device according to claim 1, wherein

the secondary battery is connected to a power supply for driving a vehicle;

and

the discharge start time detection portion detects a time when the power supply starts to operate.

6. The state of charge calculation device according to claim 1, wherein

the secondary battery is connected to an auxiliary electronic component of the vehicle;

and

the discharge start time detection portion detects a time of a start of use of the auxiliary electronic component.

7. The state of charge calculation device according to claim 1, wherein

the controller calculates an electromotive voltage based on the detected voltage, sets an electromotive voltage correction parameter which corresponds with the calculated electromotive voltage and corrects the calculated state of charge using the electromotive voltage correction parameter.

8. A state of charge calculation device that calculates a state of charge of a battery connected to a load, comprising:

a current detection portion that detects discharge current of a battery; and

a voltage detection portion that detects a voltage of the battery; and

a controller for calculating a first state of charge estimate by integrating the detected discharge current, and correcting the first state of charge estimate using an electromotive voltage correction parameter, that is determined using an electromotive voltage based on the detected voltage.

9. The state of charge calculation device according to claim 8, wherein

the controller determines a second state of charge estimate based on the electromotive voltage, determines a correction amount based on a difference between the first state of charge estimate and the second state of charge estimate using the electromotive voltage correction parameter, and corrects the second state of charge estimate using the correction amount.

10. The state of charge calculation device according to claim 8, wherein

the battery is a secondary battery, and the current detection portion detects a charge and discharge current of the secondary battery.

11. A state of charge calculation method for calculating a state of charge of a secondary battery connected to a load, comprising the steps of:

detecting a discharge current of the secondary battery; and

detecting a voltage of the secondary battery; and

detecting a time of a start of discharge to the load from the secondary battery; and

calculating the state of charge of the secondary battery based on the current and the voltage, using a method that corresponds with the time of the start of the discharge.

12. The state of charge calculation method according to claim 11, wherein

the step for detecting the time of the start of discharge detects the time of the start of discharge to the load based on one of the detected current and the detected voltage.

13. The state of charge calculation method according to claim 11, further comprising the steps of:

preparing information necessary to achieve two or more methods of calculating the state of charge of the secondary battery; and

selecting the method that corresponds with the time of the start of the discharge from among the two or more methods, wherein;

the step for calculating the state of charge calculates the state of charge of the secondary battery, based on the detected current and the detected voltage using the selected method

14. The state of charge calculation method according to claim 11, further comprising the steps of:

preparing two or more parameters that are calculated in advance, based on a characteristic value of the secondary battery; and

selecting a parameter that corresponds with the time of the start of the discharge from among the two or more prepared methods, wherein;

the step for calculating the state of charge calculates the state of charge of the secondary battery and based on the detected current the detected voltage using the method corresponding to the calculating method using the selected parameter.

15. The state of charge calculation method according to claim 11, wherein

the step for detecting the time of the start of discharge detects a time when a power supply for driving a vehicle connected to the secondary battery starts to operate.

16. The state of charge calculation method according to claim 11, wherein

the secondary battery is connected to an auxiliary electronic component of the vehicle;

and

the step for detecting the start of the discharge detects a time of a start of use of the auxiliary electronic component.

17. The state of charge calculation method according to claim 11, wherein

an electromotive voltage is calculated based on detected voltage, an electromotive voltage correction parameter that corresponds with the calculated electromotive voltage is set, and the state of charge is corrected using the electromotive voltage correction parameter.

18. A state of charge calculation method for calculating a state of charge of a battery connected to a load, comprising the steps of:

detecting a discharge current of the secondary battery; and

detecting a voltage of the secondary battery; and

detecting a time of a start of discharge to the load from the secondary battery; and

calculating a first state of charge estimate by integrating the detected discharge current; and

correcting the state of charge using an electromotive voltage correction parameter, that is determined using an electromotive voltage based on the detected voltage.

19. The state of charge calculation method according to claim 18, further comprising the steps of:

determining a second state of charge estimate based on the electromotive voltage; and

determining a correction amount based on the difference between the first state of charge estimate and the second state of charge estimate using the electromotive voltage correction parameter, wherein

the second state of charge estimate is corrected using the correction amount.

20. The state of charge calculation method according to claim 18, wherein

the battery is a secondary battery and the step of detecting current detects the charge and discharge currents of the secondary battery.