Charging method and apparatus for rechargeable battery

Patent metadata

Field	Value
Publication number	US-10211659-B2
Application number	US-201515308263-A
Country	US
Kind code	B2
Filing date	Sep 24, 2015
Priority date	Sep 24, 2015
Publication date	Feb 19, 2019
Grant date	Feb 19, 2019

Abstract

A charging method and an apparatus are provided. The charging method includes: constant-current charging the rechargeable battery until a voltage of the rechargeable battery reaches a first predetermined voltage; and charging the rechargeable battery with a gradually decreasing charging voltage until a charging process is completed. In this way, the capacity of a battery after being fully charged can be further increased while improving the charging speed.

First claim

What is claimed is:

1. A charging method, comprising:
constant-current charging a rechargeable battery until a voltage of the rechargeable battery reaches a first predetermined voltage; and
charging the rechargeable battery with a gradually decreasing charging voltage until a charging process is completed; wherein
the step of charging the rechargeable battery with a gradually decreasing charging voltage until a charging process is completed comprises:
charging the rechargeable battery with a gradually decreasing charging voltage; and
determining that the charging process is completed when a difference between a cell voltage of the rechargeable battery and the charging voltage is less than or equal to a predetermined threshold and a charging current is less than a predetermined current.

2. The method as claimed in claim 1 , wherein, charging the rechargeable battery with a gradually decreasing charging voltage comprises:
(a) constant-voltage charging the rechargeable battery with the first predetermined voltage as a charging voltage, until the cell voltage of the rechargeable battery reaches a second predetermined voltage for a first time;
(b) constant-voltage charging the rechargeable battery with a new charging voltage until the cell voltage of the rechargeable battery reaches the second predetermined voltage again, wherein the new charging voltage is less than the charging voltage applied when the cell voltage of the rechargeable battery reaches the second predetermined voltage in a previous instance; and
(c) repeating (b).

3. The method as claimed in claim 2 , wherein, when the method is performed by a mobile terminal, the first predetermined voltage is a maximum voltage permitted by a charging integrated circuit (IC) of the mobile terminal; and
the method further comprises:
monitoring the cell voltage of the rechargeable battery in real time; and
determining, according to the cell voltage of the rechargeable battery monitored in real time, that the cell voltage of the rechargeable battery reaches the second predetermined voltage.

4. The method as claimed in claim 2 , wherein, when the method is performed by a mobile terminal, the first predetermined voltage is a maximum voltage permitted by a charging integrated circuit (IC) of the mobile terminal.

5. The method as claimed in claim 2 , further comprising:
monitoring the cell voltage of the rechargeable battery in real time; and
determining, according to the cell voltage of the rechargeable battery monitored in real time, that the cell voltage of the rechargeable battery reaches the second predetermined voltage.

6. The method as claimed in claim 2 , wherein, the second predetermined voltage is a maximum voltage that the cell of the rechargeable battery can withstand.

7. The method as claimed in claim 2 , wherein the new charging voltage is a difference between the charging voltage applied when the cell voltage of the rechargeable battery reaches the second predetermined voltage in the previous instance and a predetermined voltage difference.

8. The method as claimed in claim 1 , wherein the predetermined threshold is 100 mV.

9. The method as claimed in claim 1 , wherein the rechargeable battery is a lithium-ion battery.

10. An apparatus, comprising:
a constant-current charging unit configured to constant-current charge a rechargeable battery until a voltage of the rechargeable battery reaches a first predetermined voltage; and
a constant-voltage charging unit configured to charge the rechargeable battery with a gradually decreasing charging voltage until a charging process is completed; wherein
when charging the rechargeable battery with a gradually decreasing charging voltage until a charging process is completed, the constant-voltage charging unit is configured to:
charge the rechargeable battery with a gradually decreasing charging voltage; and
determine that the charging process is completed when a difference between a cell voltage of the rechargeable battery and the charging voltage is less than or equal to a predetermined threshold and a charging current is less than a predetermined current.

11. The apparatus as claimed in claim 10 , wherein, when charging the rechargeable battery with a gradually decreasing charging voltage, the constant-voltage charging unit is configured to execute:
(a) constant-voltage charging the rechargeable battery with the first predetermined voltage as a charging voltage, until the cell voltage of the rechargeable battery reaches a second predetermined voltage for a first time;
(b) constant-voltage charging the rechargeable battery with a new charging voltage until the cell voltage of the rechargeable battery reaches the second predetermined voltage again, wherein the new charging voltage is less than the charging voltage applied when the cell voltage of the rechargeable battery reaches the second predetermined voltage in a previous instance; and
(c) repeating (b).

12. The apparatus as claimed in claim 11 , wherein, when the apparatus is a mobile terminal, the first predetermined voltage is a maximum voltage permitted by a charging integrated circuit (IC) of the mobile terminal.

13. The apparatus as claimed in claim 11 , wherein the apparatus further comprises:
a cell voltage detection unit configured to monitor the cell voltage of the rechargeable battery in real time; and
the cell voltage detection unit is also configured to determine whether the cell voltage of the rechargeable battery reaches the second predetermined voltage or not according to the cell voltage of the rechargeable battery monitored in real time.

14. The apparatus as claimed in claim 11 , wherein the second predetermined voltage is a maximum voltage that the cell of the rechargeable battery can withstand.

15. The apparatus as claimed in claim 11 , wherein the constant-voltage charging unit is configured to:
use a difference between the charging voltage applied when the cell voltage of the rechargeable battery reaches the second predetermined voltage in the previous instance and a predetermined voltage difference as the new charging voltage.

16. The apparatus as claimed in claim 10 , wherein the predetermined threshold is 100 mV.

17. The apparatus as claimed in claim 10 , wherein the rechargeable battery is a lithium-ion battery.

Assignees

• Guangdong Oppo Mobile Telecommunications Corp Ltd

Inventors

• Tian Chen
• Zhang Jun
• Zhang Jialiang

Classifications

• H02J7/875

  Charging or discharging for charge maintenance, battery initiation or rejuvenation · CPC title

• H02J7/96

  in response to battery voltage · CPC title

• H02J7/94

  in response to battery current · CPC title

• H02J7/933 Primary

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

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · CPC title