Battery control apparatus and battery control method

• US 9,438,059 B2
• Filed: 12/16/2011
• Issued: 09/06/2016
• Est. Priority Date: 12/16/2010
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Komoda, Satoru, Maruno, Naoki
• Primary Examiner(s): Dunn, Drew A
• Assistant Examiner(s): Robbins, Jerry D
• Application Number:
  US13/995,049
• Publication Number:
  US 20130271068A1
• Time in Patent Office: 1,726 Days
• Field of Search: 320/107
• US Class Current: 1/1
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2010/4271 Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/007184 in response to battery voltage gradient
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

It is intended to prevent degradation of battery cells (cells). A battery control apparatus obtains a cell voltage value of each of the cells (201) (S1), calculates a cell SOC at each of the cells based on the measured cell voltage value (S2), calculates an integrated current value (Ah) by integrating current values of a battery pack (2) configured with a plurality of the cells (201), calculates a cell capacity value of each of the cells (201) based on the integrated current value and the cell SOC (S3), calculates a dischargeable cell capacity value from the cell capacity value and the cell SOC (S4), and controls charging/discharging of the battery pack (2) based on the dischargeable cell capacity value (S5).

Claims

1. A battery control apparatus comprising:

a voltage detection unit that measures a voltage of each of cells;

a charging rate calculation unit that calculates a charging rate of each of the cells based on the measured voltage and a charging-rate to voltage table which is stored in a storage unit;

a current integration unit that calculates an integrated current value by integrating current values of a battery pack configured with a plurality of the cells;

a cell capacity estimation unit that calculates a battery capacity value of each of the cells based on the integrated current value, and the charging rate of each of the cells;

a dischargeable capacity value calculation unit that calculates a dischargeable capacity value of each of the cells from the battery capacity value and charging rate thereof; and

a control unit that controls charging or discharging of the battery pack based on the dischargeable capacity value of each of the cells

a remaining capacity comparison unit that compares the dischargeable capacity value and a predetermined target remaining capacity value,

wherein the control unit, as a result of the comparison between the dischargeable capacity value and the target remaining capacity value, discharges a cell having the dischargeable capacity value larger than the target remaining capacity value until the dischargeable capacity value reaches the target remaining capacity value.

2. The battery control apparatus, according to claim 1, further including:

a chargeable capacity value calculation unit that calculates a chargeable capacity value of each of the cells from the battery capacity value and charging rate thereof; and

a battery pack charging rate calculation unit that calculates the charging rate of the battery pack based on the respective minimum values of the dischargeable capacity values and the chargeable capacity values,

wherein the control unit performs charging/discharging of the battery pack based on the calculated charging rate of the battery pack.

3. The battery control apparatus according to claim 1,

wherein the target remaining capacity value is a dischargeable capacity value of a cell having the smallest dischargeable capacity value.

4. The battery control apparatus according to claim 1, wherein the dischargeable capacity value is calculated with following equations.

Cell capacity value=(Initial cell capacity value)×

(Δ

Ah/Δ

SOC)

Dischargeable capacity value=(Cell capacity value)×

(Current SOC−

Lower usage limit SOC)

where Δ

Ah is the integrated current value, Δ

SOC is variation of the charging rate, Current SOC is the current charging rate, and Lower usage limit SOC is a lower usage limit of the charging rate of each of the cells.

5. A battery control method for controlling charging/discharging of a battery pack, performed by a battery control apparatus, comprising steps of:

acquiring a voltage value of each of cells measured by a voltage detection unit;

calculating a charging rate of each of the cells based on the measured voltage value and a charging-rate to voltage table which is stored in a storage unit;

calculating an integrated current value by integrating current values of a battery pack that is configured with a plurality of the cells;

calculating a cell capacity value of each of the cells based on the integrated current value, and the charging rate of each of the cells;

calculating a dischargeable capacity value of each of the cells from the cell capacity value and charging rate thereof; and

controlling charging or discharging of the battery pack based on the dischargeable capacity value of each of the cells

comparing the dischargeable capacity value and a predetermined target remaining capacity value by a remaining capacity comparison unit,

wherein as a result of the comparison between the dischargeable capacity value and the target remaining capacity value, discharging a cell having the dischargeable capacity value larger than the target remaining capacity value until the dischargeable capacity value reaches the target remaining capacity value.