Battery charging method and battery management system therefor

Patent metadata

Field	Value
Publication number	US-9634497-B2
Application number	US-201514711642-A
Country	US
Kind code	B2
Filing date	May 13, 2015
Priority date	May 20, 2014
Publication date	Apr 25, 2017
Grant date	Apr 25, 2017

Abstract

A battery charging method, including obtaining a voltage capacity ratio for a reference charge C-rate and voltage capacity ratios for N (N an integer of 1 or more) charge C-rates greater than the reference charge C-rate, each of the voltage capacity ratios for the reference charge C-rate and the N charge C-rates being defined as a ratio of a voltage variance to a capacity variance depending on a change in state of charge (SOC) of a battery when the battery is charged at a corresponding one of the C-rates, comparing the voltage capacity ratio of the reference charge C-rate with each of the voltage capacity ratios of the N charge C-rates, and then setting a charge C-rate of the N charge C-rates so that a difference in voltage capacity ratio is minimized for each of SOC sections, and charging the battery with the charge C-rates corresponding to the SOC sections.

First claim

What is claimed is:

1. A battery charging method, comprising:
obtaining a voltage capacity ratio for a reference charge C-rate and voltage capacity ratios for N (N is an integer of 1 or more) charge C-rates greater than the reference charge C-rate, each of the voltage capacity ratios for the reference charge C-rate and the N charge C-rates being defined as a ratio of a voltage variance to a capacity variance depending on a change in state of charge (SOC) of a battery when the battery is charged at a corresponding one of the C-rates;
comparing the voltage capacity ratio of the reference charge C-rate with each of the voltage capacity ratios of the N charge C-rates, and then setting a charge C-rate of the N charge C-rates so that a difference in voltage capacity ratio is minimized for each of SOC sections; and
charging the battery with the charge C-rates corresponding to the SOC sections.

2. The battery charging method of claim 1 , wherein the obtaining the voltage capacity ratios comprises:
charging the battery with the reference charge C-rate, and then obtaining the voltage capacity ratio for the reference charge C-rate; and
discharging the battery and then charging the battery with a first charge C-rate greater than the C-rate of a previous charging act by a preset value, thus obtaining a corresponding one of the voltage capacity ratios for the first charge C-rate,
wherein the discharging and then charging of the battery is repeated N times so as to obtain the voltage capacity ratios for the first charge C-rate to an Nth charge C-rate.

3. The battery charging method of claim 2 , wherein the discharging of battery is performed by constant current-constant voltage (CCCV) discharging.

4. The battery charging method of claim 2 , wherein the comparing the voltage capacity ratio comprises:
selecting an SOC section in which a difference in voltage capacity ratio between the reference charge C-rate and the Nth charge C-rate is within a preset range, for all SOC sections of the battery, and then setting a charge C-rate of the selected SOC section to the Nth charge C-rate; and
selecting an SOC section in which a difference in voltage capacity ratio between the reference charge C-rate and an (N−1)th charge C-rate is within a preset range, for SOC sections other than the selected SOC section, and then setting a charge C-rate of the selected SOC section to the (N−1)th charge C-rate,
wherein selecting the SOC section is repeatedly performed for an (N−2)th charge C-rate to the first charge C-rate in substantially a same manner.

5. The battery charging method of claim 4 , wherein a charge C-rate of a section of the SOC sections in which any one of the N charge C-rates is not set, is set to the reference charge C-rate.

6. The battery charging method of claim 1 , wherein, during the charging the battery, constant current (CC) charging or constant current-constant voltage (CCCV) charging is performed in each of the SOC sections using a corresponding one of the charge C-rates.

7. The battery charging method of claim 6 , wherein, when the battery charging is performed by the CC charging, a first SOC section of the SOC sections is supplied with a corresponding one of the charge C-rates and then is charged until a voltage of the battery reaches a charge cutoff voltage set for the first SOC section.

8. The battery charging method of claim 7 , wherein, when the battery is charged at the charge C-rate corresponding to the first SOC section, a charge cutoff voltage set for the first SOC section is a voltage at which the SOC of the battery becomes a final SOC of the first SOC section.

9. The battery charging method of claim 6 , wherein, when the battery charging is performed by the CCCV charging,
a first SOC section of the SOC sections undergoes the CC charging by supplying the corresponding one of the charge C-rates until the voltage of the battery becomes a charge cutoff voltage set for the first SOC section, and undergoes constant voltage (CV) charging by supplying a charge C-rate that is sequentially reduced until the SOC of the battery becomes a final SOC of the first SOC section.

10. The battery charging method of claim 9 , wherein the charge cutoff voltage set for the first SOC section is a voltage at which the SOC of the battery becomes the final SOC of the first SOC section, when the battery is charged at a C-rate set for a second SOC section that is a section subsequent to the first SOC section.

11. The battery charging method of claim 9 , wherein the charge C-rate that is sequentially reduced is reduced to the charge C-rate set for the SOC section that is subsequent to the first SOC section.

12. The battery charging method of claim 1 , wherein, when a number of battery charging and discharging operations reaches a preset number, the obtaining the voltage capacity ratios and comparing the voltage capacity ratio are performed again to reset the charge C-rates corresponding to the SOC sections.

13. A battery management system, comprising:
a voltage-capacity-ratio acquisition unit configured to obtain a voltage capacity ratio for a reference charge C-rate and voltage capacity ratios for N (N is an integer of 1 or more) charge C-rates greater than the reference charge C-rate, each of the voltage capacity ratios for the reference charge C-rate and the N charge C-rates being defined as a ratio of a voltage variance to a capacity variance depending on a change in SOC of a battery when the battery is charged at a corresponding one of the C-rates;
a charge-current setting unit configured to compare the voltage capacity ratio of the reference charge C-rate with each of the voltage capacity ratios of the N charge C-rates, and then setting a charge C-rate of the N charge C-rates so that a difference in voltage capacity ratio is minimized for each of SOC sections; and
a micro control unit (MCU) configured to control charging of the battery such that the battery is charged at the charge C-rates corresponding to the SOC sections.

14. The battery management system of claim 13 , further comprising:
a sensing unit configured to sense a voltage and a current of the battery,
wherein the voltage-capacity-ratio acquisition unit obtains a corresponding one of the voltage capacity ratios of any one of the charge C-rates using the voltage and the current that are sensed by the sensing unit, when the battery is charged using any one of the reference charge C-rate and the N charge C-rates.

15. The battery management system of claim 13 , wherein the MCU is configured to perform CC charging or CCCV charging for each of the SOC sections, using a corresponding one of the charge C-rates.

16. The battery management system of claim 15 , wherein, when the battery charging is performed by the CC charging, a first SOC section of the SOC sections undergoes the CC charging by supplying a corresponding one of the charge C-rates until a voltage of the battery becomes a charge cutoff voltage set for the first SOC section.

17. The battery management system of claim 16 , wherein, when the battery is charged at the charge C-rate corresponding to the first SOC section, the charge cutoff voltage set for the first SOC section is a voltage at which the SOC of the battery becomes a final SOC of the first SOC section.

18. The battery management system of claim 15 , wherein, when the battery charging is performed by the CCCV charging,
a first SOC section of the SOC sections undergoes the CC charging by supplying the corresponding one of the charge C-rates until the voltage of the battery becomes a charge cutoff volta

Assignees

• Samsung Sdi Co Ltd

Inventors

• Baek Ho-Yul
• Jang Yoo-Hong
• Suh Seung-Bum
• Cheong Kyeong-Beom

Classifications

• H02J7/947

  in response to integrated charge or discharge current · CPC title

• H02J7/92

  with prioritisation of loads or sources · CPC title

• H02J7/50

  acting upon multiple batteries simultaneously or sequentially · CPC title

• H02J7/933 Primary

  the cycle being controlled or terminated in response to electric parameters · CPC title

• H02J7/0077

  Electricity · mapped topic