Calculation device calculating available capacity of secondary battery and method of calculating the same

• US 7,200,499 B2
• Filed: 10/06/2004
• Issued: 04/03/2007
• Est. Priority Date: 10/10/2003
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Aridome, Kouji
• Primary Examiner(s): Barlow; John
• Assistant Examiner(s): Khuu; Cindy D.
• Application Number:
  US10/570,311
• Publication Number:
  US 20060276981A1
• Time in Patent Office: 909 Days
• Field of Search: 702/64
• US Class Current: 702/64
• 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 method of calculating an available capacity includes the steps of: calculating a first estimated SOC from a value in voltage; calculating an integral of a value of a current and adding the integral to calculate a second estimated SOC; calculating a difference between the first and second estimated SOCs; calculating a first correction coefficient R(1) from the value in voltage; calculating a second correction coefficient R(2) to be smaller for the current having a smaller value; and adding the second estimated SOC to an correction term, or the dSOC multiplied by R(1) and R(2), to calculate a corrected SOC.

Claims

1. A calculation device calculating an available capacity of a secondary battery, comprising:

voltage detection means for detecting a value in voltage of said secondary battery;

current detection means for detecting a value of a current of said secondary battery;

means for calculating as based on said value in voltage of said secondary battery a first correction parameter employed in calculating an available capacity of said secondary battery;

means for calculating as based on said value of said current of said secondary battery a second correction parameter employed in calculating said available capacity of said secondary battery; and

calculation means using said value in voltage, said value of said current and said first and second correction parameters for calculating said available capacity of said secondary battery, wherein

said second correction parameter is increased when said secondary battery is charged/discharged by a current larger in absolute value, and

said second correction parameter is decreased when said secondary battery is charged/discharged by a current smaller in absolute value,

wherein said calculation device prevents at least one excessive discharging and excessive charging of said secondary battery based on the calculated available capacity of said secondary battery.

2. The calculation device according to claim 1, wherein said calculation means includes:

means for calculating as based on said value in voltage a first estimated available capacity from an open circuit voltage of said secondary battery;

means for calculating as based on said value of said current a second estimated available capacity from an integral of a value of a current charging/discharging said secondary battery; and

means employing a function using a difference between said first and second estimated available capacities and said first and second correction parameters to correct to said second estimated available capacity for calculating said available capacity of said secondary battery.

3. The calculation device according to claim 2, wherein said function is a function of said difference multiplied by said first and second correction parameters.

4. The calculation device according to claim 3, wherein said calculation means includes means adding a correction calculated by said function to said second estimated available capacity for calculating said available capacity of said secondary battery.

5. A method of calculating an available capacity of a secondary battery, comprising the steps of:

detecting a value in voltage of said secondary battery;

detecting a value of a current of said secondary battery;

calculating as based on said value in voltage of said secondary battery a first correction parameter employed in calculating an available capacity of said secondary battery;

calculating as based on said value of said current of said secondary battery a second correction parameter employed in calculating said available capacity of said secondary battery; and

using said value in voltage, said value of said current and said first and second correction parameters to calculate said available capacity of said secondary battery, wherein

said second correction parameter is increased when said secondary battery is charged/discharged by a current larger in absolute value, and

said second correction parameter is decreased when said secondary battery is charged/discharged by a current smaller in absolute value,

wherein said calculation device prevents at least one of excessive discharging and excessive charging of said secondary battery based on the calculated available capacity of said secondary battery.

6. The method according to claim 5, wherein the step of using includes the steps of:

calculating as based on said value in voltage a first estimated available capacity from an open circuit voltage of said secondary battery;

calculating as based on said value of said current a second estimated available capacity from an integral of a value of a current charging/discharging said secondary battery; and

employing a function using a difference between said first and second estimated available capacities and said first and second correction parameters to correct to said second estimated available capacity to calculate said available capacity of said secondary battery.

7. The method according to claim 6, wherein said function is a function of said difference multiplied by said first and second correction parameters.

8. The method according to claim 7, wherein the step of employing includes the step of adding a correction calculated by said function to said second estimated available capacity to calculate said available capacity of said secondary battery.

9. A calculation device calculating an available capacity of a secondary battery, comprising:

a voltage sensor detecting a value in voltage of said secondary battery;

a current sensor detecting a value of a current of said secondary battery;

an electronic control unit;

calculating as based on said value in voltage of said secondary battery a first correction parameter employed in calculating an available capacity of said secondary battery;

calculating as based on said value of said current of said secondary battery a second correction parameter employed in calculating said available capacity of said secondary battery; and

using said value in voltage, said value of said current and said first and second correction parameters to calculate said available capacity of said secondary battery, wherein

said second correction parameter is increased when said secondary battery is charged/discharged by a current larger in absolute value, and

said second correction parameter is decreased when said secondary battery is charged/discharged by a current smaller in absolute value.

10. The calculation device according to claim 9, wherein said electronic control unit calculates as based on said value in voltage a first estimated available capacity from an open circuit voltage of said secondary battery, calculates as based on said value of said current a second estimated available capacity from an integral of a value of a current charging/discharging said secondary battery, and employs a function using a difference between said first and second estimated available capacities and said first and second correction parameters to correct to said second estimated available capacity to calculate said available capacity of said secondary battery.

11. The calculation device according to claim 10, wherein said function is a function of said difference multiplied by said first and second correction parameters.

12. The calculation device according to claim 11, wherein said electronic control unit adds a correction calculated by said function to said second estimated available capacity to calculate said available capacity of said secondary battery.