Techniques for charging a battery pack while the battery pack operates as a backup power source to a device

Patent metadata

Field	Value
Publication number	US-10879717-B2
Application number	US-201615387974-A
Country	US
Kind code	B2
Filing date	Dec 22, 2016
Priority date	Dec 31, 2015
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

Embodiments of the present disclosure relate to a method and apparatus for charging a battery pack. The method comprises: detecting voltages of batteries in the battery pack in real time; charging the battery pack with a charging current that is at least based on the detected voltages; and performing, on the batteries in the battery pack, balance charging by a digital discharging signal. A solution according to the present disclosure may reduce the costs and achieve a more flexible and safe charging approach.

First claim

We claim:

1. A method for charging a battery pack, comprising:
detecting voltages of batteries in the battery pack in real time;
charging the battery pack with a charging current that is at least based on the detected voltages; and
performing, on the batteries in the battery pack, balance charging by a digital discharging signal,
wherein charging the battery pack with the charging current comprises:
entering a large-current charging mode in response to a minimum voltage among the voltages of the batteries in the battery pack being lower than a first voltage;
charging the battery pack with a first charging current, the first charging current having a first constant current value during the large-current charging mode;
entering a small-current charging mode in response to a maximum voltage among the voltages of the batteries in the battery pack being larger than the first voltage and a voltage difference between the maximum voltage and the minimum voltage among the voltages of the batteries in the battery pack being higher than a first voltage difference;
charging the battery pack with a second charging current, the second charging current having a second constant current value smaller than the first constant current value during the small-current charging mode, wherein entering the small-current charging mode includes entering the small-current charging mode in response to the minimum voltage among the voltages of the batteries in the battery pack being higher than a second voltage, the second voltage being lower than the first voltage;
in response to the voltage difference being lower than a second voltage difference or the maximum voltage being lower than a third voltage during the small-current charging mode, entering the large-current charging mode, the second voltage difference being lower than the first voltage difference, and the third voltage being lower than the second voltage;
in response to the maximum voltage being higher than a fourth voltage during the small-current charging mode, performing the balance charging on the batteries in the battery pack, the fourth voltage being higher than the first voltage; and
in response to the maximum voltage being lower than a fifth voltage during the small-current charging mode, entering the large-current charging mode, the fifth voltage being lower than the fourth voltage but higher than the first voltage.

2. The method according to claim 1 , wherein performing the balance charging comprises:
during the charging of the battery pack, discharging a battery in the battery pack with a voltage higher than an average voltage of the batteries in the battery pack so as to decrease voltage differences between the batteries in the battery pack.

3. The method according to claim 1 , wherein charging the battery back with the first charging current is performed in response to determining that system power is insufficient during the large-current charging mode.

4. The method according to claim 1 , wherein charging the battery back with the second charging current is performed in response to determining that system power is insufficient during the small-current charging mode.

5. The method according to claim 1 , wherein performing balance charging includes:
while the battery pack operates (i) in a charging mode and (ii) as a backup power source that supplies backup power to a data storage device, discharging a battery of the battery pack in response to the digital discharging signal which is provided by a digital signal processor of the data storage device.

6. The method according to claim 5 , wherein discharging the battery of the battery pack is performed based on a discharging loop comprising a transistor and a resistor, the transistor and the resistor being connected in series, the transistor discharging the battery via the resistor in response to the digital discharging signal.

7. An apparatus for charging a battery pack, the apparatus being configured to:
detect voltages of batteries in the battery pack in real time;
charge the battery pack with a charging current that is at least based on the detected voltages;
perform, on the batteries in the battery pack, balance charging by using a digital discharging signal;
enter a large-current charging mode in response to a minimum voltage among the voltages of the batteries in the battery pack being lower than a first voltage;
charge the battery pack with a first charging current that has a first constant current value during the large-current charging mode;
enter a small-current charging mode in response to a maximum voltage among the voltages of the batteries in the battery pack being larger than the first voltage and a voltage difference between the maximum voltage and the minimum voltage among the voltages of the batteries in the battery pack being higher than a first voltage difference;
charge the battery pack with a second charging current that has a second constant current value smaller than the first constant current value during the small-current charging mode, wherein the apparatus is further configured to enter the small-current charging mode in response to the minimum voltage among the voltages of the batteries in the battery pack being higher than a second voltage, the second voltage being lower than the first voltage;
in response to the voltage difference being lower than a second voltage difference or the maximum voltage being lower than a third voltage during the small-current charging mode, enter the large-current charging mode, the second voltage difference being lower than the first voltage difference, and the third voltage being lower than the second voltage;
in response to the maximum voltage being higher than a fourth voltage during the small-current charging mode, perform the balance charging on the batteries in the battery pack, the fourth voltage being higher than the first voltage; and
in response to the maximum voltage being lower than a fifth voltage during the small-current charging mode, entering the large-current charging mode, the fifth voltage being lower than the fourth voltage but higher than the first voltage.

8. The apparatus according to claim 7 , wherein the apparatus is further configured to:
during the charging of the battery pack, discharge a battery in the battery pack with a voltage higher than an average voltage of the batteries in the battery pack so as to decrease voltage differences between the batteries in the battery pack.

9. The apparatus according to claim 7 , wherein the apparatus is further configured to:
in response to determining that system power is insufficient during the large-current charging mode, charge the battery pack with the first charging current.

10. The apparatus according to claim 7 , wherein the apparatus is further configured to:
in response to determining that the system power is insufficient during the small-current charging mode, charge the battery pack with the second charging current.

Assignees

• Emc Ip Holding Co Llc

Inventors

• Yang Tao
• Chen Jing
• Cui Jesse Xizhi

Classifications

• H02J7/933

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

• H02J7/96

  in response to battery voltage · CPC title

• H02J7/92

  with prioritisation of loads or sources · CPC title

• H02J7/82

  Control of state of charge [SOC] · CPC title

• H02J7/54 Primary

  Passive balancing, e.g. using resistors or parallel MOSFETs · CPC title