Battery control device, battery control method, power source control device and electronic apparatus

• US 7,923,966 B2
• Filed: 08/03/2007
• Issued: 04/12/2011
• Est. Priority Date: 09/04/2006
• Status: Expired due to Fees

• Current Assignee: Fujitsu Client Computing Limited (Lenovo Group Ltd.)
• Original Assignee: Fujitsu Limited
• Inventors: Fukuda, Hideo
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): Torres Ruiz; Johali A
• Application Number:
  US11/882,698
• Publication Number:
  US 20080054909A1
• Time in Patent Office: 1,348 Days
• Field of Search: 324/430, 320/132
• US Class Current: 320/132
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A battery control device 1 has an electric circuit control unit 6 controlling a power supply; a voltage measuring unit 7 measuring a voltage; a current measuring unit 8 measuring an electric current; and a power source control unit 9, wherein the power source control unit 9 measures a first voltage defined as the voltage of the battery 4 and a first current defined as the current of the battery 4 in a state where the battery 4 supplies electric power to the load 3, measures a second voltage defined as the voltage of the battery 4 in a state where the supply of the electric power to the load 3 from the battery 4 is cut off, and calculates internal impedance of the battery 4 by dividing a value, obtained in a way that subtracts the first voltage from the second voltage, by the first current.

Claims

1. A battery control device, comprising:

an electric circuit control unit controlling a power supply to a load from a battery;

a voltage measuring unit measuring a voltage of the battery;

a current measuring unit measuring an electric current of the battery;

a power source control unit outputting a control signal to the electric circuit control unit and receiving measurement signals from the voltage measuring unit and the current measuring unit; and

a pre-generated map representing a relationship between the open-circuit voltage and a battery residual quantity ratio defined as a value showing a ratio at which a residual quantity of the battery occupies the whole capacity thereof,

wherein the power source control unit calculates an internal impedance of the battery by measuring a first voltage defined as the voltage of the battery and a first current defined as the current of the battery in a state where the battery supplies electric power to the load, measuring a second voltage defined as the voltage of the battery in a state where the supply of the electric power to the load from the battery is cut off and dividing a value obtained in a way that subtracts the first voltage from the second voltage by the first current,

calculates an open-circuit voltage of the battery by measuring a third voltage defined as the voltage of the battery and a second current defined as the electric current of the battery in the state where the battery supplies the electric power to the load and adding the third voltage to a value obtained in a way that multiplies the internal impedance by the second current,

acquires the battery residual quantity ratio of the battery by collating the open-circuit voltage with the pre-generated map,

measures a first battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage in a first battery state as a battery state before the residual quantity decreases and collating the open-circuit voltage with the map,

measures a second battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage of the battery in a second battery state that is a battery state after the residual quantity has decreased and collating the open-circuit voltage with the map,

measures a first integrated current defined as an integrated value of the electric current outputted during a transition of the battery from the first battery state to the second battery state, and

calculates the full-charge capacity of the battery in a way that divides the first integrated current by a value obtained by subtracting the second battery residual quantity ratio from the first battery residual quantity ratio.

2. A battery control device according to claim 1,

wherein the power source control unit further measures a second integrated current defined as an integrated value of the electric current outputted during a transition of the residual quantity of the battery from a full-charge state to a 100% state, and

further corrects the full-charge capacity of the battery by adding the second integrated current to the full-charge capacity.

3. A battery control device according to claim 1, wherein the power source control unit further corrects the full-charge capacity by multiplying the full-charge capacity by a value obtained by adding “

1”

to a ratio at which the capacity till the residual quantity of the battery reaches an over-discharge state from a 0% state, occupies the whole capacity.

4. A battery control device according to claim 1,

further comprising a temperature detecting unit measuring a temperature of the battery,

wherein the power source control unit further calculates the full-charge capacity when the temperature of the battery is equal to or higher than a predetermined temperature.

5. A battery control device according to claim 1,

wherein the first battery state is a state before the battery starts supplying the electric power to the load, and

the second battery state is a state after the battery has stopped supplying the electric power to the load.

6. A battery control device according to claim 1, wherein a relationship between the battery residual quantity ratio and the open-circuit voltage, which are specified in the map, is a relationship specified by data previously measured by a measuring device when manufacturing the battery.

7. A battery control device according to claim 1,

wherein the electric circuit control unit includes:

a first diode disposed on a power supply circuit that connects the battery to the load without a switch along a path of the power supply circuit; and

a switch disposed on a power supply circuit to the load from a power source device of which a voltage is higher than the voltage of the battery, and

wherein when opening the switch, the electric power is supplied to the load from the battery while cutting off the power supply to the load from the power source device, and, when closing the switch, the power supply to the load from the battery is cut off while supplying the electric power to the load from the power source device.

8. A battery control method of a battery control device comprising:

controlling, with an electric circuit control unit, a power supply to a load from a battery;

measuring a voltage of the battery;

measuring an electric current of the battery; and

outputting, with a power source control unit, a control signal to the electric circuit control unit and receiving measurement signals from the voltage measuring unit and the current measuring unit,

wherein the power source control unit calculates an internal impedance of the battery by measuring a first voltage defined as the voltage of the battery and a first current defined as the current of the battery in a state where the battery supplies electric power to the load, measuring a second voltage defined as the voltage of the battery in a state where the supply of the electric power to the load from the battery is cut off and dividing a value obtained in a way that subtracts the first voltage from the second voltage by the first current,

calculates an open-circuit voltage of the battery by measuring a third voltage defined as the voltage of the battery and a second current defined as the electric current of the battery in the state where the battery supplies the electric power to the load and adding the third voltage to a value obtained in a way that multiplies the internal impedance by the second current,

acquires the battery residual quantity ratio of the battery by collating the open-circuit voltage with a pre-generated map representing a relationship between the open-circuit voltage and a battery residual quantity ratio defined as a value showing a ratio at which a residual quantity of the battery occupies the whole capacity thereof,

measures a first battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage in a first battery state as a battery state before the residual quantity decreases and collating the open-circuit voltage with the map,

measures a second battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage of the battery in a second battery state that is a battery state after the residual quantity has decreased and collating the open-circuit voltage with the map,

measures a first integrated current defined as an integrated value of the electric current outputted during a transition of the battery from the first battery state to the second battery state, and

calculates the full-charge capacity of the battery in a way that divides the first integrated current by a value obtained by subtracting the second battery residual quantity ratio from the first battery residual quantity ratio.

9. A battery control method according to claim 8,

wherein the power source control unit further measures a second integrated current defined as an integrated value of the electric current outputted during a transition of the residual quantity of the battery from a full-charge state to a 100% state, and

further corrects the full-charge capacity of the battery by adding the second integrated current to the full-charge capacity.

10. A battery control method according to claim 8, wherein the power source control unit further corrects the full-charge capacity by multiplying the full-charge capacity by a value obtained by adding “

1”

to a ratio at which the capacity till the residual quantity of the battery reaches an over-discharge state from a 0% state, occupies the whole capacity.

11. A battery control method according to claim 8,

wherein the battery control device further includes temperature detecting unit measuring a temperature of the battery,

wherein the power source control unit further calculates the full-charge capacity when the temperature of the battery is equal to or higher than a predetermined temperature.

12. A battery control method according to claim 8,

wherein the first battery state is a state before the battery starts supplying the electric power to the load, and

the second battery state is a state after the battery has stopped supplying the electric power to the load.

13. A battery control method according to claim 8, wherein a relationship between the battery residual quantity ratio and the open-circuit voltage, which are specified in the map, is a relationship specified by data previously measured by a measuring device when manufacturing the battery.

14. A battery control method according to claim 8,

wherein the electric circuit control unit includes:

a first diode disposed on a power supply circuit that connects the battery to the load without a switch along a path of the power supply circuit; and

a switch disposed on a power supply circuit to the load from a power source device of which a voltage is higher than the voltage of the battery, and

wherein when opening the switch, the electric power is supplied to the load from the battery while cutting off the power supply to the load from the power source device, and, when closing the switch, the power supply to the load from the battery is cut off while supplying the electric power to the load from the power source device.

15. A power source control device used for an electronic apparatus comprising:

an electric circuit control unit controlling a power supply to a load from a battery;

a voltage measuring unit measuring a voltage of the battery;

a current measuring unit measuring an electric current of the battery; and

a pre-generated map representing a relationship between the open-circuit voltage and a battery residual quantity ratio defined as a value showing a ratio at which a residual quantity of the battery occupies the whole capacity thereof,

wherein the power source control unit calculates an internal impedance of the battery by measuring a first voltage defined as the voltage of the battery and a first current defined as the current of the battery in a state where the battery supplies electric power to the load, measuring a second voltage defined as the voltage of the battery in a state where the supply of the electric power to the load from the battery is cut off and dividing a value obtained in a way that subtracts the first voltage from the second voltage by the first current,

calculates an open-circuit voltage of the battery by measuring a third voltage defined as the voltage of the battery and a second current defined as the electric current of the battery in the state where the battery supplies the electric power to the load and adding the third voltage to a value obtained in a way that multiplies the internal impedance by the second current,

acquires the battery residual quantity ratio of the battery by collating the open-circuit voltage with the pre-generated map,

measures a first battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage in a first battery state as a battery state before the residual quantity decreases and collating the open-circuit voltage with the map,

measures a second battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage of the battery in a second battery state that is a battery state after the residual quantity has decreased and collating the open-circuit voltage with the map,

measures a first integrated current defined as an integrated value of the electric current outputted during a transition of the battery from the first battery state to the second battery state, and

calculates the full-charge capacity of the battery in a way that divides the first integrated current by a value obtained by subtracting the second battery residual quantity ratio from the first battery residual quantity ratio.

16. A power source control device according to claim 15,

wherein the electric circuit control unit includes:

a first diode disposed on a power supply circuit that connects the battery to the load without a switch along a path of the power supply circuit; and

a switch disposed on a power supply circuit to the load from a power source device of which a voltage is higher than the voltage of the battery, and

wherein when opening the switch, the electric power is supplied to the load from the battery while cutting off the power supply to the load from the power source device, and, when closing the switch, the power supply to the load from the battery is cut off while supplying the electric power to the load from the power source device.

17. An electronic apparatus including a battery and driven by electric power, comprising:

an electric circuit control unit controlling a power supply to a load within the electronic apparatus from a battery;

a voltage measuring unit measuring a voltage of the battery;

a current measuring unit measuring an electric current of the battery;

a power source control unit outputting a control signal to the electric circuit control unit, and receiving measurement signals from the voltage measuring unit and the current measuring unit; and

a pre-generated map representing a relationship between the open-circuit voltage and a battery residual quantity ratio defined as a value showing a ratio at which a residual quantity of the battery occupies the whole capacity thereof,

wherein the power source control unit calculates an internal impedance of the battery by measuring a first voltage defined as the voltage of the battery and a first current defined as the current of the battery in a state where the battery supplies electric power to the load, measuring a second voltage defined as the voltage of the battery in a state where the supply of the electric power to the load from the battery is cut off and dividing a value obtained in a way that subtracts the first voltage from the second voltage by the first current,

calculates an open-circuit voltage of the battery by measuring a third voltage defined as the voltage of the battery and a second current defined as the electric current of the battery in the state where the battery supplies the electric power to the load and adding the third voltage to a value obtained in a way that multiplies the internal impedance by the second current,

acquires the battery residual quantity ratio of the battery by collating the open-circuit voltage with the pre-generated map,

measures a first battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage in a first battery state as a battery state before the residual quantity decreases and collating the open-circuit voltage with the map,

measures a second battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage of the battery in a second battery state that is a battery state after the residual quantity has decreased and collating the open-circuit voltage with the map,

measures a first integrated current defined as an integrated value of the electric current outputted during a transition of the battery from the first battery state to the second battery state, and

calculates the full-charge capacity of the battery in a way that divides the first integrated current by a value obtained by subtracting the second battery residual quantity ratio from the first battery residual quantity ratio.

18. An electronic apparatus according to claim 17,

wherein the electric circuit control unit includes:

a first diode disposed on a power supply circuit that connects the battery to the load without a switch along a path of the power supply circuit; and

a switch disposed on a power supply circuit to the load from a power source device of which a voltage is higher than the voltage of the battery, and

wherein when opening the switch, the electric power is supplied to the load from the battery while cutting off the power supply to the load from the power source device, and, when closing the switch, the power supply to the load from the battery is cut off while supplying the electric power to the load from the power source device.

19. A recording medium recorded with a battery control program for a battery control device comprising:

an electric circuit control unit controlling a power supply to a load from a battery;

a voltage measuring unit measuring a voltage of the battery;

a current measuring unit measuring an electric current of the battery;

a power source control unit outputting a control signal to the electric circuit control unit, and receiving measurement signals from the voltage measuring unit and the current measuring unit; and

a pre-generated map representing a relationship between the open-circuit voltage and a battery residual quantity ratio defined as a value showing a ratio at which a residual quantity of the battery occupies the whole capacity thereof,

the program making the battery control device execute;

calculating an internal impedance of the battery by measuring a first voltage defined as the voltage of the battery and a first current defined as the current of the battery in a state where the battery supplies electric power to the load, measuring a second voltage defined as the voltage of the battery in a state where the supply of the electric power to the load from the battery is cut off and dividing a value obtained in a way that subtracts the first voltage from the second voltage by the first current,

calculating an open-circuit voltage of the battery by measuring a third voltage defined as the voltage of the battery and a second current defined as the electric current of the battery in the state where the battery supplies the electric power to the load and adding the third voltage to a value obtained in a way that multiplies the internal impedance by the second current,

acquiring the battery residual quantity ratio of the battery by collating the open-circuit voltage with the pre-generated map,

measuring a first battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage in a first battery state as a battery state before the residual quantity decreases and collating the open-circuit voltage with the map,

measuring a second battery residual quantity ratio defined as a value showing a ratio at which the residual quantity of the battery occupies the whole capacity thereof by calculating the open-circuit voltage of the battery in a second battery state that is a battery state after the residual quantity has decreased and collating the open-circuit voltage with the map,

measuring a first integrated current defined as an integrated value of the electric current outputted during a transition of the battery from the first battery state to the second battery state, and

calculating the full-charge capacity of the battery in a way that divides the first integrated current by a value obtained by subtracting the second battery residual quantity ratio from the first battery residual quantity ratio.

20. A recording medium according to claim 19,

wherein the electric circuit control unit includes:

a first diode disposed on a power supply circuit that connects the battery to the load without a switch along a path of the power supply circuit; and

a switch disposed on a power supply circuit to the load from a power source device of which a voltage is higher than the voltage of the battery, and

wherein when opening the switch, the electric power is supplied to the load from the battery while cutting off the power supply to the load from the power source device, and, when closing the switch, the power supply to the load from the battery is cut off while supplying the electric power to the load from the power source device.