Method for detecting deterioration of electrochemical device, method for measuring remaining capacity, charger comprising them, and discharge controller

• US 6,480,003 B1
• Filed: 03/29/2001
• Issued: 11/12/2002
• Est. Priority Date: 06/18/1999
• Status: Expired due to Term

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Takeyama, Kenichi, Ugaji, Masaya, Kayama, Miho
• Primary Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/762,974
• Time in Patent Office: 593 Days
• Field of Search: 324/430, 320/132, 320/134, 320/136
• US Class Current: 324/430
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/345 Gastight metal hydride accumulators
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• 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

The present invention is a deterioration detecting method for an electrochemical device comprising electrodes and an ion conductor, wherein an electrochemical characteristic of the electrochemical device is detected, and an obtained value is then compared with a standard electrochemical characteristic of the electrochemical device to estimate the degree of deterioration of the electrochemical device. Further, the capacity of the device is found based on the detected degree of deterioration, and using this and the output of the device, a remaining capacity of the device is estimated. Accordingly, the degree of deterioration and the remaining capacity of an electrochemical device such as a secondary battery can be accurately detected.

Claims

1. A deterioration detecting method for an electrochemical device comprising electrodes and an ion conductor, wherein an electrochemical characteristic of said electrochemical device is detected, and an obtained detection value indicating said electrochemical characteristic is then compared with a previously stored reference value indicating a standard electrochemical characteristic of said electrochemical device to estimate the degree of deterioration of said electrochemical device.

2. The deterioration detecting method for an electrochemical device in accordance with claim 1, wherein a model which expresses an electrochemical characteristic of a component of said electrochemical device by a parameter, a value of said parameter indicating said electrochemical characteristic of said component is calculated from a detection value obtained by detecting said electrochemical characteristic of said electrochemical device, and said value of said parameter is compared with a reference value indicating a standard electrochemical characteristic of said component to estimate the degree of deterioration of said electrochemical device.

3. The deterioration detecting method for an electrochemical device in accordance with claim 2, wherein said parameter is the sum of the internal resistance of said electrode and the internal resistance of said ion conductor.

4. The deterioration detecting method for an electrochemical device in accordance with claim 2, wherein said model comprises at least one selected from the group consisting of a potential model of said electrode, an electron transport model of said electrode, an ion transport model of said electrode, an ion transport model of said ion conductor, and a model representing an electrochemical reaction occurring in the interface between said electrode and said ion conductor.

5. A remaining capacity detecting method for an electrochemical device, wherein a capacity value of said electrochemical device is estimated based on the degree of deterioration obtained by the deterioration detecting method for an electrochemical device in accordance with claim 1, and a remaining capacity of said electrochemical device is calculated using the obtained capacity value.

8. The deterioration detecting method of claim 1, wherein said previously stored reference value represents the value of the standard electrochemical characteristic of said electrochemical device prior to deterioration of said electrochemical device.

6. A charger comprising:

a means for detecting an electrochemical characteristic of a battery;

a means for estimating the degree of deterioration of said battery by comparing an obtained electrochemical characteristic with a previously stored reference value indicating a standard electrochemical characteristic of said battery; and

a means for controlling the discharge of said battery based on an obtained degree of deterioration.

9. The charger according to claim 6, further comprising storage means for storing said reference value.

11. The charger according to claim 6, wherein said previously stored reference value represents the value of the standard electrochemical characteristic of said battery prior to deterioration of said battery.

7. A discharge controlling apparatus comprising:

a means for detecting an electrochemical characteristic of a battery;

a means for estimating the degree of deterioration of said battery by comparing an obtained electrochemical characteristic with a previously stored reference value indicating a standard electrochemical characteristic of said battery; and

a means for controlling the discharge of said battery based on an obtained degree of deterioration.

10. The discharge controlling apparatus according to claim 7, further comprising storage means for storing said reference value.

12. The discharge controlling apparatus according to claim 7, wherein said previously stored reference value represents the value of the standard