Battery state estimation device and battery state estimation method

• US 8,909,490 B2
• Filed: 02/18/2011
• Issued: 12/09/2014
• Est. Priority Date: 02/18/2010
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Nakamura, Hideo, Tazoe, Kazuhiko, Segawa, Satoshi, Umeki, Shiho, Asai, Hisafumi
• Primary Examiner(s): Huynh, Phuong
• Application Number:
  US13/393,507
• Publication Number:
  US 20120316812A1
• Time in Patent Office: 1,390 Days
• Field of Search: 702 63- 65, 702182-190
• US Class Current: 702/63
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

An object of the present invention is to provide a battery state estimation device and a battery state estimation method which identify parameter of a secondary battery with high accuracy. A current and a terminal voltage of secondary battery are detected, then by using the current measured value and terminal voltage measured value thus detected, the terminal voltage of secondary battery based on predetermined battery model is estimated, and the parameter of the secondary battery is identified such that a difference between terminal voltage measured value and voltage estimated value is converged to zero. In the identifying of parameter of secondary battery, the terminal voltage measured value and terminal voltage estimated value are subjected to filter treatment by low pass filter having a common high frequency breaking characteristic and the terminal voltage measured value and terminal voltage estimated value subjected to the filter treatment are used.

Claims

1. A battery state estimation device, comprising:

a current detector for detecting, as a current measured value, a current of a secondary battery;

a voltage detector for detecting, as a voltage measured value, a terminal voltage of the secondary battery;

a state variable filter operator which defines a battery model of the secondary battery, wherein by using a state variable filter which is based on the battery model, the state variable filter operator subjects to a state quantity conversion the current measured value and the voltage measured value to thereby calculate a conversion state quantity, and from the conversion state quantity, the state variable filter operator estimates, as a voltage estimated value, the terminal voltage of the secondary battery which terminal voltage is based on the battery model; and

an adaptive identification operator for identifying a parameter of the secondary battery such that a difference between the voltage measured value and the voltage estimated value is converged to zero,

wherein the adaptive identification operator subjects the voltage measured value and the voltage estimated value to a filter treatment by a low pass filter having a common high frequency breaking characteristic and calculates the difference by using the voltage measured value and the voltage estimated value which are subjected to the filter treatment by the low pass filter.

3. The battery state estimation device according to claim 1 wherein a cutoff frequency of the low pass filter is more than or equal to a cutoff frequency of the state variable filter.

4. The battery state estimation device according to claim 3 wherein the cutoff frequency of the low pass filter is equal to the cutoff frequency of the state variable filter.

5. The battery state estimation device according to claim 1 wherein the low pass filter and the state variable filter are free from a differentiator.

6. The battery state estimation device according to claim 1 wherein the low pass filter and the state variable filter include only a serial connection or a parallel connection of a primary low pass filter.

2. A battery state estimation device, comprising:

a current detector for detecting, as a current measured value, a current of a secondary battery;

a voltage detector for detecting, as a voltage measured value, a terminal voltage of the secondary battery;

a low pass filter operator for subjecting the current measured value and the voltage measured value to a filter treatment by a low pass filter having a common high frequency breaking characteristic;

a state variable filter operator which defines a battery model of the secondary battery, wherein by using a state variable filter which is based on the battery model, the state variable filter operator subjects to a state quantity conversion the current measured value and the voltage measured value which are subjected to the filter treatment by the low pass filter to thereby calculate a conversion state quantity, and from the conversion state quantity, the state variable filter operator estimates, as a voltage estimated value, the terminal voltage of the secondary battery which terminal voltage is based on the battery model; and

an adaptive identification operator for identifying a parameter of the secondary battery such that a difference between the voltage measured value subjected to the filter treatment by the low pass filter and the voltage estimated value is converged to zero.

7. A battery state estimation device, comprising:

a current detecting means for detecting, as a current measured value, a current of a secondary battery;

a voltage detecting means for detecting, as a voltage measured value, a terminal voltage of the secondary battery;

a terminal voltage estimating means which defines a battery model of the secondary battery, wherein by using a state variable filter which is based on the battery model, the terminal voltage estimating means subjects to a state quantity conversion the current measured value and the voltage measured value to thereby calculate a conversion state quantity, and from the conversion state quantity, the terminal voltage estimating means estimates, as a voltage estimated value, the terminal voltage of the secondary battery which terminal voltage is based on the battery model; and

an identifying means for identifying a parameter of the secondary battery such that a difference between the voltage measured value and the voltage estimated value is converged to zero,

wherein the identifying means subjects the voltage measured value and the voltage estimated value to a filter treatment by a low pass filter having a common high frequency breaking characteristic and calculates the difference by using the voltage measured value and the voltage estimated value which are subjected to the filter treatment by the low pass filter.

8. A battery state estimation device, comprising:

a current detecting means for detecting, as a current measured value, a current of a secondary battery;

a voltage detecting means for detecting, as a voltage measured value, a terminal voltage of the secondary battery;

a low pass filter operating means for subjecting the current measured value and the voltage measured value to a filter treatment by a low pass filter having a common high frequency breaking characteristic;

a terminal voltage estimating means which defines a battery model of the secondary battery, wherein by using a state variable filter which is based on the battery model, the terminal voltage estimating means subjects to a state quantity conversion the current measured value and the voltage measured value which are subjected to the filter treatment by the low pass filter to thereby calculate a conversion state quantity, and from the conversion state quantity, the terminal voltage estimating means estimates, as a voltage estimated value, the terminal voltage of the secondary battery which terminal voltage is based on the battery model; and

an identifying means for identifying a parameter of the secondary battery such that a difference between the voltage measured value subjected to the filter treatment by the low pass filter and the voltage estimated value is converged to zero.

9. A battery state estimation method, comprising:

detecting, as a current measured value, a current of a secondary battery;

detecting, as a voltage measured value, a terminal voltage of the secondary battery;

defining a battery model of the secondary battery;

by using a state variable filter which is based on the battery model, subjecting to a state quantity conversion the current measured value and the voltage measured value to thereby calculate a conversion state quantity;

from the conversion state quantity, estimating, as a voltage estimated value, the terminal voltage of the secondary battery which terminal voltage is based on the battery model; and

identifying a parameter of the secondary battery such that a difference between the voltage measured value and the voltage estimated value is converged to zero,

wherein the identifying of the parameter of the secondary battery such that the difference between the voltage measured value and the voltage estimated value is converged to zero includes;

subjecting the voltage measured value and the voltage estimated value to a filter treatment by a low pass filter having a common high frequency breaking characteristic, and

calculating the difference by using the voltage measured value and the voltage estimated value which are subjected to the filter treatment by the low pass filter.

10. A battery state estimation method, comprising:

detecting, as a current measured value, a current of a secondary battery;

detecting, as a voltage measured value, a terminal voltage of the secondary battery;

subjecting the current measured value and the voltage measured value to a filter treatment by a low pass filter having a common high frequency breaking characteristic;

defining a battery model of the secondary battery;

by using a state variable filter which is based on the battery model, subjecting to a state quantity conversion the current measured value and the voltage measured value which are subjected to the filter treatment by the low pass filter to thereby calculate a conversion state quantity;

from the conversion state quantity, estimating, as a voltage estimated value, the terminal voltage of the secondary battery which terminal voltage is based on the battery model; and

identifying a parameter of the secondary battery such that a difference between the voltage measured value subjected to the filter treatment by the low pass filter and the voltage estimated value is converged to zero.