Method and apparatus for estimating remaining capacity of secondary battery

• US 7,339,351 B2
• Filed: 12/02/2002
• Issued: 03/04/2008
• Est. Priority Date: 12/27/2001
• Status: Active Grant

• Current Assignee: Panasonic EV Energy Company, Limited (Toyota Motor Corporation)
• Original Assignee: Panasonic EV Energy Company, Limited (Toyota Motor Corporation)
• Inventors: Egoshi, Teruyoshi, Takada, Masahiro, Yamabe, Norito, Murakami, Yusai
• Primary Examiner(s): Tso; Edward H
• Application Number:
  US10/496,426
• Publication Number:
  US 20050017725A1
• Time in Patent Office: 1,919 Days
• Field of Search: 320/132, 320/149, 324/426, 324/427, 324/430, 324/433
• US Class Current: 320/132
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 50/10 using propulsion power supplied by engine-driven generators, e.g. generators driven by combustion engines
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• 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
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

There is provided a battery pack system with estimation accuracy of a remaining capacity of a secondary batter enhanced. A current accumulation coefficient correction section 109 calculates a correction amount α with respect to a current accumulation coefficient k in accordance with a battery electromotive force Veq from an electromotive force calculation section 105. A remaining capacity calculation section 112 estimates a remaining capacity SOC by current accumulation, based on the current accumulation coefficient k calculated from a correction amount α, and a charging efficiency η based on a currently estimated remaining capacity calculated by a charging efficiency calculation section 110.

Claims

1. A method for estimating a remaining capacity of a secondary battery, comprising the steps of:

measuring data sets of a current flowing through a secondary battery and a terminal voltage of the secondary battery corresponding to the current, and obtaining a plurality of the data sets;

calculating an electromotive force of the secondary battery based on the obtained plurality of data sets;

determining a correction amount with respect to a current accumulation coefficient in accordance with the calculated electromotive force;

calculating the current accumulation coefficient from the correction amount and a charging efficiency;

multiplying the calculated current accumulation coefficient by the measured current, and estimating a remaining capacity of the secondary battery by current accumulation; and

controlling the remaining capacity by charging or discharging the secondary battery using the estimated remaining capacity of the secondary battery.

2. A method for estimating a remaining capacity of a secondary battery, comprising the steps of:

measuring data sets of a current flowing through a battery pack including a combination of a plurality of cells that are secondary batteries and used in an intermediately charged state and a terminal voltage of the secondary battery corresponding to the current, and obtaining a plurality of the data sets;

calculating an electromotive force of the secondary battery based on the obtained plurality of data sets;

determining a correction amount with respect to a current accumulation coefficient in accordance with the calculated electromotive force;

calculating the current accumulation coefficient from the correction amount and a charging efficiency;

multiplying the calculated current accumulation coefficient by the measured current, and estimating a remaining capacity of the secondary battery by current accumulation; and

controlling the remaining capacity by charging of or discharging the secondary battery using the estimated remaining capacity of the secondary battery.

3. A battery pack system comprising a computer system for executing the method for estimating a remaining capacity of a secondary battery of claim 2, and the battery pack.

4. A motor-driven vehicle on which a battery pack system comprising a computer system for performing the method for estimating a remaining capacity of a secondary battery of claim 2, and the battery pack.

5. An apparatus for estimating a remaining capacity of a secondary battery, comprising:

a current measuring section for measuring a current flowing through a secondary battery as current data;

a voltage measuring section for measuring a terminal voltage of the secondary battery corresponding to the current as voltage data;

an electromotive force calculation section for calculating an electromotive force of the secondary battery based on a plurality of data sets of the current data from the current measuring section and the voltage data from the voltage measuring section;

a current accumulation coefficient correction section for determining a correction amount with respect to a current accumulation coefficient in accordance with the electromotive force from the electromotive force calculation section;

an adder for outputting the current accumulation coefficient from the correction amount from the current accumulation coefficient correction section and a charging efficiency; and

a remaining capacity estimation section for multiplying the current accumulation coefficient from the adder by the current data, and estimating a remaining capacity of the secondary battery by current accumulation.

6. An apparatus for estimating a remaining capacity of a secondary battery, comprising:

a current measuring section for measuring a current flowing through a battery pack having a combination of a plurality of cells that are secondary batteries and used in an intermediately charged state, as current data;

a voltage measuring section for measuring a terminal voltage of the secondary battery corresponding to the current as voltage data;

an electromotive force calculation section for calculating an electromotive force of the secondary battery based on a plurality of data sets of the current data from the current measuring section and the voltage data from the voltage measuring section;

a current accumulation coefficient correction section for determining a correction amount with respect to a current accumulation coefficient, in accordance with the electromotive force from the electromotive force calculation section;

an adder for outputting the current accumulation coefficient from the correction amount from the current accumulation coefficient correction section and a charging efficiency; and

a remaining capacity estimation section for multiplying the current accumulation coefficient from the adder by the current data, and estimating the remaining capacity of a secondary battery by current accumulation.

7. A battery pack system comprising the apparatus for estimating a remaining capacity of a secondary battery of claim 6, and the battery pack.

8. A motor-driven vehicle on which a battery pack system comprising the apparatus for estimating a remaining capacity of a secondary battery of claim 6 and the battery pack is mounted.