System and method for measuring internal resistance of battery

• US 9,612,291 B2
• Filed: 03/07/2015
• Issued: 04/04/2017
• Est. Priority Date: 10/24/2014
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Sung, Woo Suk, Hwang, Do Sung
• Primary Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US14/641,327
• Publication Number:
  US 20160116546A1
• Time in Patent Office: 759 Days
• Field of Search: 324430
• CPC Class Codes: G01R 31/374 with means for correcting the measurement for temperature or ageing
• CPC Class Codes: G01R 31/389 Measuring internal impedance, internal conductance or related variables
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A system and method for more accurately measuring an internal resistance of a battery for a vehicle are provided. The method includes measuring, by a controller, current-voltage pairs for the battery and calculating a correlation between current and voltage in the measured current-voltage pairs. In addition, the internal resistance of the battery is measured using the current-voltage pairs having the correlation equal to or greater than a preset threshold.

Claims

1. A method for measuring an internal resistance of a battery of a battery management system, comprising:

measuring, by a controller, current-voltage pairs for the battery;

calculating, by the controller, a correlation between current and voltage in the measured current-voltage pairs, wherein in the calculation of the correlation, a ratio of a regression sum of squares (SSR) to a total sum of squares (SST) is calculated, where the total sum of squares (SST) represents a total variation of a dependent variable Y in a regression equation and the regression sum of squares (SSR) represents a difference between a predicted value for a value X_i of an independent variable X of a case i and the mean of observed value of a dependent variable Y in the regression equation; and

measuring, by the controller, the internal resistance of the battery using the current-voltage pairs having the correlation equal to or greater than a preset threshold.

2. The method according to claim 1, wherein the threshold is about 0.9.

3. The method according to claim 1, wherein in the measuring of the internal resistance, a resistance value is calculated based on a least mean square using data of the current-voltage pairs.

4. The method according to claim 1, wherein in the measuring of the internal resistance, when a temperature T of the battery satisfies a condition of 25°

C.<

T<

30°

C., a resistance value is calculated.

5. A system for measuring an internal resistance of a battery of a battery management system, comprising:

a memory configured to store a plurality of program instructions

a process configured to execute the program instructions, the program instructions when executed configured to;

measure current-voltage pairs for the battery using a sensor;

calculate a correlation between current and voltage in the measured current-voltage pairs, wherein in the calculation of the correlation, a ratio of a regression sum of squares (SSR) to a total sum of squares (SST) is calculated, where the total sum of squares (SST) represents a total variation of a dependent variable Y in a regression equation and the regression sum of squares (SSR) represents a difference between a predicted value for a value X_i of an independent variable X of a case i and the mean of observed value of a dependent variable Y in the regression equation; and

measure the internal resistance of the battery using the current-voltage pairs having the correlation equal to or greater than a preset threshold.

6. The system according to claim 5, wherein the threshold is about 0.9.

7. The system according to claim 5, wherein in the measuring of the internal resistance, a resistance value is calculated based on a least mean square using data of the current-voltage pairs.

8. The system according to claim 5, wherein in the measuring of the internal resistance, when a temperature T of the battery satisfies a condition of 25°

C.<

T<

30°

C., a resistance value is calculated.

9. A non-transitory computer readable medium containing program instructions executed by a controller, the computer readable medium comprising:

program instructions that control a sensor to measure current-voltage pairs for the battery;

program instructions that calculate a correlation between current and voltage in the measured current-voltage pairs, wherein in the calculation of the correlation, a ratio of a regression sum of squares (SSR) to a total sum of squares (SST) is calculated, where the total sum of squares (SST) represents a total variation of a dependent variable Y in a regression equation and the regression sum of squares (SSR) represents a difference between a predicted value for a value X_i of an independent variable X of a case i and the mean of observed value of a dependent variable Y in the regression equation; and

program instructions that measure the internal resistance of the battery using the current-voltage pairs having the correlation equal to or greater than a preset threshold.

10. The non-transitory computer readable medium of claim 9, wherein the threshold is about 0.9.

11. The non-transitory computer readable medium of claim 9, wherein in the measuring of the internal resistance, a resistance value is calculated based on a least mean square using data of the current-voltage pairs.

12. The non-transitory computer readable medium of claim 9, wherein in the measuring of the internal resistance, when a temperature T of the battery satisfies a condition of 25°

C.<

T<

30°

C., a resistance value is calculated.