POST-DETERIORATION PERFORMANCE ESTIMATING APPARATUS AND POST-DETERIORATION PERFORMANCE ESTIMATING METHOD FOR ENERGY STORAGE DEVICE, AND ENERGY STORAGE SYSTEM

• US 20150301118A1
• Filed: 11/27/2013
• Published: 10/22/2015
• Est. Priority Date: 11/30/2012
• Status: Active Grant

• Current Assignee: GS Yuasa International Ltd. (GS Yuasa Corporation)
• Original Assignee: GS Yuasa International Ltd. (GS Yuasa Corporation)
• Inventors: Tao, Yohei, Yamate, Shigeki
• Granted Patent: US 9,581,653 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 31/385 Arrangements for measuring battery or accumulator variables for monitoring G01R31/382
• 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: H01M 10/4285 Testing apparatus
• 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: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

A post-deterioration performance estimating apparatus estimates a post-deterioration performance value indicating performance of an energy storage device at a predetermined deterioration point, wherein discharge capacity of the energy storage device discharging at a predetermined first current is referred to as energy storage capacity, discharge capacity of the energy storage device discharging at a second current of a current value smaller than that of the first current is referred to as small current discharge capacity, a relational expression on relation among initial capacity of the energy storage device, a first capacity decreased amount obtained by subtracting the small current discharge capacity from the initial capacity, a second capacity decreased amount obtained by subtracting the energy storage capacity from the small current discharge capacity, and a cumulative operating period as a cumulative value of operating periods of the energy storage device is referred to as a first relational expression, and the post-deterioration performance estimating apparatus includes a post-deterioration performance estimator configured to estimate the post-deterioration performance value at the deterioration point in accordance with the first relational expression and the cumulative operating period at the deterioration point.

Claims

1. A post-deterioration performance estimating apparatus configured to estimate a post-deterioration performance value indicating performance of an energy storage device at a predetermined deterioration point, wherein

discharge capacity of the energy storage device discharging at a predetermined first current is referred to as energy storage capacity, discharge capacity of the energy storage device discharging at a second current of a current value smaller than that of the first current is referred to as small current discharge capacity, a relational expression on relation among initial capacity of the energy storage device, a first capacity decreased amount obtained by subtracting the small current discharge capacity from the initial capacity, a second capacity decreased amount obtained by subtracting the energy storage capacity from the small current discharge capacity, and a cumulative operating period as a cumulative value of operating periods of the energy storage device is referred to as a first relational expression, and

the post-deterioration performance estimating apparatus includes a post-deterioration performance estimator configured to estimate the post-deterioration performance value at the deterioration point in accordance with the first relational expression and the cumulative operating period at the deterioration point.

2. The post-deterioration performance estimating apparatus according to claim 1, wherein

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the first relational expression including the initial capacity, the first capacity decreased amount, the second capacity decreased amount, and a member of an exponential function of the cumulative operating period.

3. The post-deterioration performance estimating apparatus according to claim 1, wherein

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the first relational expression including a second relational expression on relation among the initial capacity, the first capacity decreased amount, the second capacity decreased amount, and a resistance value of direct current resistance or alternating current resistance of the energy storage device and a third relational expression on relation between the resistance value and the cumulative operating period.

4. The post-deterioration performance estimating apparatus according to claim 3, wherein

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the second relational expression on relation between capacity ratio, as a ratio of the second capacity decreased amount to the small current discharge capacity, and the resistance value.

5. The post-deterioration performance estimating apparatus according to claim 4, wherein

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the second relational expression on the capacity ratio that is expressed by a linear function of the resistance value.

6. The post-deterioration performance estimating apparatus according to claim 3, wherein

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the second relational expression that has a coefficient varying depending on whether operating temperature of the energy storage device exceeds or is not more than predetermined temperature.

7. The post-deterioration performance estimating apparatus according to claim 4, wherein

the post-deterioration performance estimator includes:

a data acquiring unit configured to acquire the small current discharge capacity at the deterioration point;

a capacity ratio calculator configured to calculate the capacity ratio at the deterioration point in accordance with the resistance value at the deterioration point and the second relational expression; and

a post-deterioration performance calculator configured to calculate the post-deterioration performance value in accordance with a fourth relational expression on relation among the post-deterioration performance value, the acquired small current discharge capacity, and the calculated capacity ratio.

8. The post-deterioration performance estimating apparatus according to claim 7, wherein

the post-deterioration performance calculator calculates the post-deterioration performance value by multiplying a value obtained by subtracting the capacity ratio from one and the small current discharge capacity.

9. The post-deterioration performance estimating apparatus according to claim 3, wherein

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the third relational expression on the resistance value at a time point after elapse of the cumulative operating period, the resistance value being in proportion to an exponential function that has a variable obtained by multiplying the cumulative operating period and a predetermined coefficient.

10. The post-deterioration performance estimating apparatus according to claim 9, wherein

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the third relational expression having the predetermined coefficient that is an exponential function having a reciprocal of the operating temperature of the energy storage device as a variable.

11. The post-deterioration performance estimating apparatus according to claim 10, wherein

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the third relational expression that has the coefficient in the exponential function having the reciprocal of the operating temperature of the energy storage device as the variable, the coefficient varying depending on whether the operating temperature of the energy storage device exceeds or is not more than predetermined temperature.

12. The post-deterioration performance estimating apparatus according to claim 3, wherein

the post-deterioration performance estimator includes:

a data acquiring unit configured to acquire the cumulative operating period at the deterioration point; and

a resistance value calculator configured to calculate the resistance value at the deterioration point in accordance with the acquired cumulative operating period and the third relational expression.

13. The post-deterioration performance estimating apparatus according to claim 1, wherein

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the first relational expression obtained from the first capacity decreased amount that includes a member of a square root of the cumulative operating period and has, as a coefficient in the member of the square root, an exponential function having a reciprocal of the operating temperature of the energy storage device as a variable.

14. The post-deterioration performance estimating apparatus according to claim 1, wherein

the post-deterioration performance estimator

further includes a relational expression corrector configured to correct the first relational expression, and

estimates the post-deterioration performance value in accordance with the corrected first relational expression.

15. The post-deterioration performance estimating apparatus according to claim 1, wherein

the energy storage device is a lithium-ion secondary battery containing layered lithium transition metal oxide as a positive active material, and

the post-deterioration performance estimator estimates the post-deterioration performance value in accordance with the first relational expression for the lithium-ion secondary battery.

16. An energy storage system comprising:

an energy storage device; and

the post-deterioration performance estimating apparatus according to claim 1, configured to estimate a post-deterioration performance value as discharge capacity of the energy storage device at a predetermined deterioration point.

17. A post-deterioration performance estimating method of estimating, with a computer, a post-deterioration performance value indicating performance of an energy storage device at a predetermined deterioration point, wherein

discharge capacity of the energy storage device discharging at a predetermined first current is referred to as energy storage capacity, discharge capacity of the energy storage device discharging at a second current of a current value smaller than that of the first current is referred to as small current discharge capacity, a relational expression on relation among a first capacity decreased amount obtained by subtracting the small current discharge capacity from initial capacity of the energy storage device, a second capacity decreased amount obtained by subtracting the energy storage capacity from the small current discharge capacity, and a cumulative operating period as a cumulative value of operating periods of the energy storage device is referred to as a first relational expression, and

the post-deterioration performance estimating method includes the post-deterioration performance estimating step of estimating the post-deterioration performance value at the deterioration point in accordance with the first relational expression and the cumulative operating period at the deterioration point.

18. An integrated circuit configured to estimate a post-deterioration performance value indicating performance of an energy storage device at a predetermined deterioration point, wherein

discharge capacity of the energy storage device discharging at a predetermined first current is referred to as energy storage capacity, discharge capacity of the energy storage device discharging at a second current of a current value smaller than that of the first current is referred to as small current discharge capacity, a relational expression on relation among a first capacity decreased amount obtained by subtracting the small current discharge capacity from initial capacity of the energy storage device, a second capacity decreased amount obtained by subtracting the energy storage capacity from the small current discharge capacity, and a cumulative operating period as a cumulative value of operating periods of the energy storage device is referred to as a first relational expression, and

the integrated circuit includes a post-deterioration performance estimator configured to estimate the post-deterioration performance value at the deterioration point in accordance with the first relational expression and the cumulative operating period at the deterioration point.