Fast charging method and related device for series battery pack

Patent metadata

Field	Value
Publication number	US-10819124-B2
Application number	US-201916353539-A
Country	US
Kind code	B2
Filing date	Mar 14, 2019
Priority date	Sep 14, 2016
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

A fast charging method, a fast charging system, and a fast charging apparatus for a series battery pack, where the fast charging method including obtaining charge parameters of battery units in a series battery pack, determining, based on the charge parameters, whether there is a differentiated battery unit in the series battery pack, where the differentiated battery unit is a battery unit whose charge parameter is different from a charge parameter of the rest battery units in the series battery pack, and changing the battery units in the series battery pack to a parallel connection when there is a differentiated battery unit in the series battery pack, and performing parallel charging on the battery units. Hence, the fast charging method for a series battery pack can effectively shorten a charging time.

First claim

What is claimed is:

1. A fast charging method for a series battery pack, comprising:
obtaining charge parameters of battery units in the series battery pack;
determining, based on the charge parameters, whether there is a differentiated battery unit in the series battery pack, wherein the differentiated battery unit is a battery unit whose charge parameter is different from charge parameters of remaining battery units in the series battery pack;
changing the battery units to a parallel coupling when there is the differentiated battery unit in the series battery pack;
performing parallel charging on the battery units;
monitoring charging statuses of the battery units;
detecting that charging of the battery units is completed;
ending the charging of the battery units; and
changing the battery units to one of: a series coupling, a series-parallel coupling, or the parallel coupling based on a load power requirement.

2. The fast charging method of claim 1 , wherein determining whether there is the differentiated battery unit in the series battery pack comprises:
obtaining a charge parameter characteristic curve of each battery unit, wherein the charge parameter characteristic curve defines a characteristic of how a charge parameter of a corresponding battery unit changes with a charge cycle quantity of the corresponding battery unit;
obtaining a charge cycle quantity of each battery unit in the series battery pack;
determining, based on the charge parameter characteristic curve of each battery unit, a charge parameter characteristic value of each battery unit at a corresponding charge cycle quantity;
comparing the charge parameter of the corresponding battery unit with a charge parameter characteristic value of the corresponding battery unit;
identifying that there is a battery unit whose charge parameter is less than a charge parameter characteristic value by more than a preset threshold; and
determining, in response to the identifying, that there is the differentiated battery unit in the series battery pack.

3. The fast charging method of claim 2 , wherein the obtained charge parameter characteristic curve is based on a selected material and a battery structure of the battery unit.

4. The fast charging method of claim 1 , wherein changing the battery units in the series battery pack to the parallel coupling and performing the parallel charging on the battery units comprises:
controlling switching transistors in a switch array to be on or off to change the battery units in the series battery pack to an all-parallel coupling; and
performing all-parallel charging on the battery units.

5. The fast charging method of claim 1 , wherein before changing the battery units in the series battery pack to the parallel coupling, the fast charging method further comprises:
obtaining a maximum charging current allowed by a charging trunk and a charging current of all-parallel charging; and
comparing the charging current with the maximum charging current.

6. The fast charging method of claim 5 , wherein the maximum charging current allowed by the charging trunk is greater than or equal to the charging current of the all-parallel charging, and wherein changing the battery units in the series battery pack to the parallel coupling and performing the parallel charging on the battery units comprises:
changing the battery units in the series battery pack to an all-parallel coupling; and
performing the all-parallel charging on the battery units.

7. The fast charging method of claim 5 , wherein the maximum charging current is less than the charging current, and wherein changing the battery units in the series battery pack to the parallel coupling and performing the parallel charging on the battery units comprises:
changing the battery units in the series battery pack to a series-parallel coupling; and
performing series-parallel charging on the battery units.

8. The fast charging method of claim 7 , wherein changing the battery units in the series battery pack to the series-parallel coupling comprises:
calculating, based on the maximum charging current allowed by the charging trunk and maximum charging currents of the battery units, a maximum quantity of battery units allowed to be coupled in parallel; and
changing the battery units in the series battery pack to the series-parallel coupling based on the maximum quantity of the battery units allowed to be coupled in parallel.

9. The fast charging method of claim 7 , wherein after performing the series-parallel charging on the battery units, the fast charging method further comprises:
monitoring charging statuses of the battery units;
detecting that charging of the differentiated battery unit is completed;
triggering, in response to the detecting, a charging loop to bypass the differentiated battery unit using a bypass switching transistor in a switch array coupled to the differentiated battery unit;
re-determining a new maximum charging current based on a quantity of the remaining battery units; and
performing charging on the remaining battery units using the new maximum charging current.

10. The fast charging method of claim 1 , wherein changing the battery units in the series battery pack to the parallel coupling and performing the parallel charging on the battery units comprises:
controlling switching transistors in a switch array to be on or off to change the battery units in the series battery pack to a series-parallel coupling; and
performing series-parallel charging on the battery units.

11. A fast charging system, comprising:
a charging control circuit;
an alternating current (AC)/direct current (DC) conversion circuit coupled to the charging control circuit and configured to convert an AC signal from an external power supply to a DC signal; and
a series battery pack coupled to the charging control circuit using a switch array, wherein the series battery pack comprises a plurality of battery units coupled in series, and
wherein the charging control circuit is configured to:
obtain charge parameters of the battery units;
obtain a charge parameter characteristic curve of each battery unit;
obtain a charge cycle quantity of each battery unit in the series battery pack;
determine, based on the charge parameter characteristic curve of each battery unit, a charge parameter characteristic value of each battery unit at a corresponding charge cycle quantity;
compare the charge parameter of the corresponding battery unit with a charge parameter characteristic value of the corresponding battery unit;
identify that there is a battery unit whose charge parameter is less than a charge parameter characteristic value by more than a preset threshold;
determine, in response to the identifying, whether there is a differentiated battery unit in the series battery pack, wherein the differentiated battery unit is a battery unit whose charge parameter is different from charge parameters of remaining battery units in the series battery pack;
control the switch array to change the battery units in the series battery pack to an all-parallel coupling or a series-parallel coupling when there is the differentiated battery unit in the series battery pack; and
perform all-parallel charging or series-parallel charging on the battery units using the DC signal.

12. The fast charging system of claim 11 , wherein the charging control circuit is further configured to:
obtain a maximum charging current allowed by a charging trunk and a charging current of the all-parallel charging;
compare the charging current with the maximum charging current; and
control the switch array to change the battery units in the series b

Assignees

• Huawei Tech Co Ltd

Inventors

• Li Yingtao
• Zhou Kui
• Zhang Guanghui
• Wang Pinghua

Classifications

• H02J7/963

  in response to battery voltage gradient · CPC title

• H02J7/953

  in response to charge current gradient · CPC title

• H02J7/575 Primary

  Parallel/serial switching of connection of batteries to charge or load circuit · CPC title

• H01M10/486

  for measuring temperature · CPC title

• H01M10/482

  for several batteries or cells simultaneously or sequentially · CPC title