Semiconductor Integrated Circuit Having Battery Control Function and Operation Method Thereof

• US 20120306450A1
• Filed: 05/23/2012
• Published: 12/06/2012
• Est. Priority Date: 05/30/2011
• Status: Active Grant

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Renesas Electronics Corporation
• Inventors: NAKAYAMA, Yoko, Inoue, Takeshi
• Granted Patent: US 8,970,174 B2
• Time in Patent Office: Days
• US Class Current: 320/134
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• CPC Class Codes: G06F 1/263 Arrangements for using multiple switchable power supplies, e.g. battery and AC G06F1/30 takes precedence

Abstract

A semiconductor integrated circuit is capable of being supplied with battery current information and battery voltage information. The semiconductor integrated circuit includes a memory function, a current integrating function, a voltage-based state of charge operating function, a current-based state of charge operating function, a comparison determination function, a correcting function, and a resistance deterioration coefficient output function. The memory function stores the relation between a state of charge of a battery and an internal resistance deterioration coefficient thereof. The full charge capacity outputted from the correcting function and the internal resistance deterioration coefficient outputted from the resistance deterioration coefficient output function are stored in the memory function when a voltage-based state of charge and a current-based state of charge compared by the comparison determination function are determined to substantially coincide with each other.

Claims

1. A semiconductor integrated circuit having a battery control function capable of controlling at least one of a discharge operation and a charge operation of a battery,

said semiconductor integrated circuit being capable of being supplied with current information generated from a current detection unit for detecting a current of the battery and voltage information generated from a voltage detection unit for detecting a voltage of the battery,

said semiconductor integrated circuit comprising a memory function, a current integrating function, a voltage-based state of charge operating function, a current-based state of charge operating function, a comparison determination function, a correcting function, and a resistance deterioration coefficient output function,

wherein the memory function is capable of:

storing therein a relation between a full charge capacity of the battery and an internal resistance deterioration coefficient of the battery, and

storing therein the full charge capacity outputted from the correcting function and the internal resistance deterioration coefficient outputted from the resistance deterioration coefficient output function, when the comparison determination function determines that a voltage-based state of charge and a current-based state of charge substantially coincide with each other.

2. The semiconductor integrated circuit according to claim 1,

wherein the memory function is capable of storing an initial value of the full charge capacity and an initial value of the current-based state of charge therein,

wherein the current integrating function is supplied with the current information to thereby enable a current integrated value to be outputted therefrom,

wherein the voltage-based state of charge operating function is supplied with the current information and the voltage information to thereby enable a voltage-based state of charge to be outputted therefrom,

wherein the current-based state of charge operating function is supplied with the initial value of the full charge capacity and the initial value of the current-based state of charge both outputted from the memory function, and the current integrated value outputted from the current integrating function to thereby enable a current-based state of charge to be outputted therefrom,

wherein the comparison determination function is supplied with the voltage-based state of charge and the current-based state of charge to thereby enable a comparison output signal corresponding to a difference between the voltage-based state of charge and the current-based state of charge to be outputted therefrom,

wherein the correcting function is supplied with the comparison output signal outputted from the comparison determination function and the initial value of the full charge capacity outputted from the memory function to thereby enable a corrected calculated value of the full charge capacity to be outputted therefrom,

wherein the resistance deterioration coefficient output function is capable of outputting the internal resistance deterioration coefficient in response to the corrected calculated value of the full charge capacity outputted from the correcting function,

wherein immediately after the start of a discharge operation, when the voltage-based state of charge and the current-based state of charge substantially coincide with each other, the memory function is capable of storing therein:

the corrected calculated value of the full charge capacity outputted from the correcting function; and

either the voltage-based state of charge as the initial value of the full charge capacity, or the current-based state of charge as the initial value of the current-based state of charge, or both.

3. The semiconductor integrated circuit according to claim 2, further including a resistance parameter output function,

wherein the resistance parameter output function comprises a table indicative of a relation between the voltage-based state of charge outputted from the voltage-based state of charge operating function and an internal resistance of the battery,

wherein the resistance parameter output function is capable of outputting a resistance parameter of the internal resistance of the battery in response to the voltage-based state of charge outputted from the voltage-based state of charge operating function,

wherein as battery discharge continues, the resistance parameter output function:

calculates the internal resistance of the battery; and

updates a method of outputting the resistance parameter of the internal resistance of the battery, in response to the voltage-based state of charge.

4. The semiconductor integrated circuit according to claim 3, wherein:

the circuit is configured to calculate the full charge capacity of the battery, based on a state of charge calculated based on an open-circuit voltage of the battery when a few hours have elapsed after the end of discharge of the battery, and an integrated value of the discharging current of the battery generated from the current detection unit during the discharge of the battery,

the circuit is configured to calculate the internal resistance deterioration coefficient, based on current and voltage values of the battery during the discharge of the battery, and

the circuit is capable of updating the relation between the full charge capacity and the internal resistance deterioration coefficient, both stored in the memory function based on the result of calculation of the full charge capacity when the few hours have elapsed after the end of discharge of the battery, and the result of calculation of the internal resistance deterioration coefficient during the discharge of the battery.

5. The semiconductor integrated circuit according to claim 2,

wherein the semiconductor integrated circuit is configured to calculate a state of charge available, a remaining capacity and a remaining time of the battery, based on the full charge capacity and the internal resistance deterioration coefficient.

6. The semiconductor integrated circuit according to claim 2,

wherein immediately after the start of a charge operation, when the voltage-based state of charge and the current-based state of charge substantially coincide with each other, the memory function is capable of storing therein:

the corrected calculated value of the full charge capacity outputted from the correcting function; and

either the voltage-based state of charge as the initial value of the full charge capacity, or the current-based state of charge as the initial value of the current-based state of charge, or both.

7. The semiconductor integrated circuit according to claim 3, wherein:

the resistance parameter output function is configured to calculate the internal resistance of the battery, based on the closed-circuit voltage of the battery generated from the voltage detection unit and the discharging current of the battery generated from the current detection unit, and

the resistance parameter output function is capable of updating the method of outputting the resistance parameter of the internal resistance of the battery, in accordance with the result of calculation of the internal resistance of the battery.

8. The semiconductor integrated circuit according to claim 4, wherein:

the circuit is configured to calculate the full charge capacity of the battery based on the state of charge calculated based on the open-circuit voltage of the battery generated from the voltage detection unit and the integrated value of the charging current of the battery generated from the current diction unit during the charge of the battery, when a few hours have elapsed after the end of charge of the battery;

the circuit is configured to calculate the internal resistance deterioration coefficient, based on the current and voltage values of the battery during the charge of the battery, and

the circuit is capable of updating the relation between the full charge capacity and the internal resistance deterioration coefficient stored in the memory function, based on the result of calculation of the full charge capacity when the few hours have elapsed after the end of charge of the battery, and the result of calculation of the internal resistance deterioration coefficient during the charge of the battery.

9. The semiconductor integrated circuit according to claim 1, wherein in a charge operation, the circuit is configured to:

execute a constant current charge for a first portion of the charge, and execute a constant voltage charge for a latter portion of the charge,

calculate a state of charge at a change point at which the constant current charge is switched to the constant voltage charge and then calculate a constant current charging time (Tcc) for the constant current charge and a constant voltage charging time (Tcv) for the constant voltage charge, and

output a sum of the constant current charging time (Tcc) and the constant voltage charging time (Tcv) as a remaining charge time.

10. The semiconductor integrated circuit according to claim 9, wherein the circuit is configured to:

calculate the constant voltage charging time (Tcv) based on the state of charge of the battery and a linear approximation of the charging current for the constant voltage charge.

11. The semiconductor integrated circuit according to claim 10, wherein the circuit is configured to:

calculate the change-point state of charge based on either;

a timing at which the closed-circuit voltage taken during the period of the constant voltage charge of the battery coincides with a limit voltage for the constant voltage charge, or

a timing at which the charging current taken during the period of the constant voltage charge of the battery coincides with a constant current for the constant current charge,

update the calculated change-point state of charge to an actual change-point state of charge calculated based on a change from the constant current charge to the constant voltage charge during the actual charge of the battery, and

recalculate the constant voltage charging time (Tcv) by using the actual change-point state of charge to thereby update an output value of the remaining charging time.

12. The semiconductor integrated circuit according to claim 11,

wherein the memory function is achieved by a nonvolatile memory built in the semiconductor integrated circuit.

13. A method of operating a semiconductor integrated circuit having a battery control function capable of controlling at least one of discharge and charge operations of a battery, said semiconductor integrated circuit comprising a memory function, a current integrating function, a voltage-based state of charge operating function, a current-based state of charge operating function, a comparison determination function, a correcting function, and a resistance deterioration coefficient output function, said method comprising the steps of:

storing a relation between a full charge capacity of the battery and an internal resistance deterioration coefficient of the battery in the memory function;

supplying current information generated from a current detection unit for detecting a current of the battery and voltage information generated from a voltage detection unit for detecting a voltage of the battery to the semiconductor integrated circuit respectively; and

storing in the memory function, the full charge capacity outputted from the correcting function and an internal resistance deterioration coefficient outputted from the resistance deterioration coefficient output function, when it is determined that a voltage-based state of charge and a current-based state of charge compared with each other by the comparison determination function substantially coincide with each other.

14. The method according to claim 13, further including the steps of:

storing an initial value of the full charge capacity and an initial value of the current-based state of charge in the memory function;

supplying the current information to the current integrating function to thereby output a current integrated value;

supplying the current information and the voltage information to the voltage-based state of charge operating function to thereby output a voltage-based state of charge;

supplying the initial value of the full charge capacity and the initial value of the current-based state of charge from the memory function, and the current integrated value outputted from the current integrating function to the current-based state of charge operating function to thereby output a current-based state of charge;

supplying the voltage-based state of charge and the current-based state of charge to the comparison determination function to thereby output a comparison output signal corresponding to a difference between the voltage-based state of charge and the current-based state of charge from the comparison determination function;

supplying the comparison output signal outputted from the comparison determination function and the initial value of the full charge capacity outputted from the memory function to the correcting function to thereby output a corrected calculated value of the full charge capacity from the correcting function;

outputting the internal resistance deterioration coefficient from the resistance deterioration coefficient output function in response to the corrected calculated value of the full charge capacity outputted from the correcting function; and

immediately after the start of the discharge operation, when the voltage-based state of charge and the current-based state of charge substantially coincide with each other, storing to the memory function;

the corrected calculated value of the full charge capacity outputted from the correcting function; and

either the voltage-based state of charge as the initial value of the full charge capacity, or the current-based state of charge as the initial value of the current-based state of charge, or both.

15. The method according to claim 14, wherein:

said semiconductor integrated circuit further includes a resistance parameter output function comprising a table indicative of a relation between the voltage-based state of charge outputted from the voltage-based state of charge operating function and an internal resistance of the battery, and

said operation method further includes the steps of;

outputting a resistance parameter of the internal resistance of the battery from the resistance parameter output function in response to the voltage-based state of charge;

during the continuation of discharge of the battery, calculating the internal resistance of the battery, based on a closed-circuit voltage of the battery generated from the voltage detection unit and a discharging current of the battery generated from the current detection unit; and

updating a method of outputting the resistance parameter of the internal resistance of the battery from the resistance parameter output function in accordance with the result of calculation of the internal resistance of the battery during the continuation of the discharge of the battery.

16. The method according to claim 15, including the steps of:

calculating the full charge capacity of the battery, based on a state of charge calculated based on an open-circuit voltage of the battery generated from the voltage detection unit when a few hours have elapsed after the end of discharge of the battery, and an integrated value of the discharging current of the battery generated from the current detection unit during the discharge of the battery,

calculating the internal resistance deterioration coefficient, based on current and voltage values of the battery during the discharge of the battery, and

updating the relation between the full charge capacity and the internal resistance deterioration coefficient, both stored in the memory function, based on the result of calculation of the full charge capacity when the few hours have elapsed after the end of discharge of the battery, and the result of calculation of the internal resistance deterioration coefficient during the discharge of the battery.

17. The method according to claim 14, further including the step of calculating a state of charge available, a remaining capacity and a remaining time of the battery by the semiconductor integrated circuit, based on the full charge capacity and the internal resistance deterioration coefficient.

18. The method according to claim 15, wherein:

in a charge operation, the battery is charged with a constant current for a first portion of the charge and the battery is charges with a constant voltage for a latter portion of the charge, and

said operation method includes the steps of;

calculating a state of charge at a change point when the constant current charge is switched to the constant voltage charge,

calculating a constant current charging time (Tcc) for the constant current charge and a calculating a constant voltage charging time (Tcv) for the constant voltage charge from the change-point state of charge, and

outputting a sum of the constant current charging time (Tcc) and the constant voltage charging time (Tcv) as a remaining charge time.

19. The method according to claim 18, comprising:

calculating the constant voltage charging time (Tcv) based on the state of charge of the battery and a linear approximation of the charging current for the constant voltage charge.

20. The method according to claim 19, comprising:

calculating the change-point state of charge based on either;

a timing at which the closed-circuit voltage taken during the period of the constant voltage charge of the battery coincides with a limit voltage for the constant voltage charge, or

a timing at which the charging current taken during the period of the constant voltage charge of the battery coincides with a constant current for the constant current charge;

updating the change-point state of charge to an actual change-point state of charge calculated based on a change from the constant current charge to the constant voltage charge during the actual charge of the battery, and

recalculating the constant voltage charging time (Tcv) by using the actual change-point state of charge to thereby update an output value of the remaining charging time.