Battery management system and method of driving the same

• US 7,847,557 B2
• Filed: 08/29/2007
• Issued: 12/07/2010
• Est. Priority Date: 08/29/2006
• Status: Active Grant

• Current Assignee: Samsung SDI Company Limited
• Original Assignee: Samsung SDI Company Limited
• Inventors: Lee, Jae-Moon, Choi, Soo-Seok, Lee, Young-Jo, Yun, Han-Seok, Cho, Bo-Hyung
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): OMAR, AHMED H
• Application Number:
  US11/846,753
• Publication Number:
  US 20080054848A1
• Time in Patent Office: 1,196 Days
• Field of Search: 324/430
• US Class Current: 324/430
• 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 31/389 Measuring internal impedance, internal conductance or related variables

Abstract

A battery management system that estimates an internal impedance of a battery, a method of driving the same, a device that estimates an internal impedance of a battery, and a method of estimating the internal impedance of a battery. A method of driving a battery management system that estimates the internal impedance of a battery including a plurality of cells includes generating a battery equivalent model of the battery, receiving a terminal voltage signal and a charge and discharge current signal of the battery, and generating a first discrete signal corresponding to the terminal voltage signal of the battery and a second discrete signal corresponding to the charge and discharge current signal of the battery, and filtering the first discrete signal and the second discrete signal according to a frequency range corresponding to the battery equivalent model so as to estimate the internal impedance of the battery. The device that estimates an internal impedance of a battery filters the first discrete signal and the second discrete signal according to a frequency range corresponding to the battery equivalent model so as to estimate the internal impedance of the battery.

Claims

1. A method of driving a battery management system that estimates an internal impedance of a battery including a plurality of cells, the method comprising:

generating a battery equivalent model of the battery;

receiving a terminal voltage signal and a charge and discharge current signal of the battery;

generating a first discrete signal corresponding to the terminal voltage signal of the battery;

generating a second discrete signal corresponding to the charge and discharge current signal of the battery;

estimating the internal impedance of the battery by filtering the first discrete signal and the second discrete signal according to a frequency range corresponding to the battery equivalent model;

generating a third discrete signal by filtering the first discrete signal according to the frequency range corresponding to the battery equivalent model; and

generating a fourth discrete signal by filtering the second discrete signal according to the frequency range corresponding to the battery equivalent model,

wherein the generating of the battery equivalent model comprises;

calculating a first parameter, which represents a resistance overvoltage corresponding to the internal impedance of the battery;

calculating a second parameter, which represents a charge transfer overvoltage;

calculating a third parameter, which represents a diffusion overvoltage; and

calculating a fourth parameter, which represents an open circuit voltage;

dividing the first to fourth parameters according to a frequency domain; and

the estimating of the internal impedance of the battery further comprises;

filtering the first parameter by using a high-pass filter,

filtering the second parameter by using a band-pass filter, and

filtering the third and fourth parameters by using a low-pass filter.

2. The method of claim 1, wherein the estimating of the internal impedance further comprises:

using a bilinear conversion method to generate the first to fourth discrete signals.

3. The method of claim 1, wherein the battery equivalent model comprises:

a first capacitor and a first resistor connected in parallel to represent a charge transfer impedance of the battery;

a second capacitor and a second resistor connected in parallel to represent a diffusion impedance of the battery;

a third resistor to represent a series resistance impedance of the battery; and

an open circuit voltage component to represent an open circuit voltage of the battery.

4. The method of claim 1, further comprising:

dividing the first to fourth parameters according to a frequency domain; and

estimating of the internal impedance further comprises;

filtering the first parameter by using a high-pass filter; and

filtering the second, third, and fourth parameters by using a low-pass filter.

5. The method of claim 1, further comprising:

estimating the first to fourth parameters by using the third discrete signal and the fourth discrete signal; and

estimating a resistor and a capacitor that correspond to the internal impedance of the battery by using the first to fourth parameters.

6. The method of claim 5, further comprising:

estimating the first to fourth parameters by using the third discrete signal and the fourth discrete signal by using a least square estimation method.

7. A battery management system that estimates an internal impedance of a battery including a plurality of cells, the system comprising:

an anti-aliasing low-pass filter that receives a battery terminal voltage signal and a battery terminal current signal and removes aliasing of the battery terminal voltage signal and the battery terminal current signal so as to generate a first signal and a second signal;

a continuous/discrete signal converter that converts the first signal and the second signal from the anti-aliasing low-pass filter into discrete signals according to a sampling time, and thereby generates a first discrete signal corresponding to the first signal and a second discrete signal corresponding to the second signal; and

an impedance estimating unit that estimates the internal impedance of the battery by filtering the first and the second discrete signals according to a frequency range corresponding to a battery equivalent model of the battery,

wherein the impedance estimating unit further;

generates a third discrete signal by filtering the first discrete signal and a fourth discrete signal by filtering the second discrete signal according to the frequency range corresponding to the battery equivalent model of the battery;

estimates the internal impedance of the battery by using a third discrete signal and a fourth discrete signal,

wherein the battery equivalent model includes four parameters, each of which corresponds to the internal impedance of the battery, the four parameters comprising;

a first parameter, which represents resistance overvoltage;

a second parameter, which represents a charge transfer overvoltage;

a third parameter, which represents a diffusion overvoltage; and

a fourth parameter, which represents an open circuit voltage; and

wherein the impedance estimating unit;

divides the four parameters according to a frequency domain; and

filters the first parameter by using a high-pass filter;

filters the second parameter by using a band-pass filter; and

filters the third and the fourth parameters by using a low-pass filter.

8. The system of claim 7, wherein the impedance estimating unit further:

estimates the four parameters by using the third discrete signal and the fourth discrete signal; and

estimates a resistor and a capacitor that correspond to the internal impedance of the battery using the four parameters.