Fast charging method and related device for parallel battery pack

Patent metadata

Field	Value
Publication number	US-10826305-B2
Application number	US-201916351517-A
Country	US
Kind code	B2
Filing date	Mar 13, 2019
Priority date	Sep 14, 2016
Publication date	Nov 3, 2020
Grant date	Nov 3, 2020

Abstract

A fast charging method for a parallel battery pack is provided, including: obtaining a maximum charging current allowed by a charging trunk and a charging current required for charging a parallel battery pack; comparing the charging current required for charging the parallel battery pack with the maximum charging current allowed by the charging trunk; if the charging current required for charging the parallel battery pack is less than or equal to the maximum charging current allowed by the charging trunk, performing parallel charging on battery units; or if the charging current required for charging the parallel battery pack is greater than the maximum charging current allowed by the charging trunk, changing some or all of battery units in the parallel battery pack to a series connection, and performing series charging on the battery units. The fast charging method for a parallel battery pack can effectively shorten a charging time.

First claim

What is claimed is:

1. A fast charging method for a parallel battery pack, comprising:
obtaining a maximum charging current allowed by a charging trunk and a charging current required for charging a parallel battery pack;
comparing the charging current required for charging the parallel battery pack with the maximum charging current allowed by the charging trunk;
if the charging current required for charging the parallel battery pack is less than or equal to the maximum charging current allowed by the charging trunk, performing parallel charging on battery units; or
if the charging current required for charging the parallel battery pack is greater than the maximum charging current allowed by the charging trunk, changing at least a portion of battery units in the parallel battery pack to a series connection, and performing series charging on the battery units

wherein before the changing all of the battery units in the parallel battery pack to a series connection, the method further comprises:
obtaining charge parameters of the battery units in the parallel battery pack based on charge parameter characteristic curves each of which is indicative of how a charge parameter of a respective battery unit changes with a charge cycle quantity of the battery unit;
determining, based on the charge parameters, whether there is a differentiated battery unit in the parallel battery pack; and
if there is a differentiated battery unit in the parallel battery pack, changing some of the battery units in the parallel battery pack to a series connection.

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

3. The method according to claim 1 , wherein the changing some of the battery units in the parallel battery pack to a series connection comprises:
calculating, based on the maximum charging current allowed by the charging trunk and a maximum charging current allowed by each of the battery units, a maximum quantity of battery units allowed to be connected in parallel; and
changing the battery units in the parallel battery pack to a series-parallel connection based on the maximum quantity of battery units allowed to be connected in parallel.

4. The method according to claim 3 , wherein after the performing series charging on the battery units, the method further comprises:
monitoring charging statuses of the battery units;
in response to detecting that charging of the differentiated battery unit is completed, making a charging loop bypass the differentiated battery unit using a bypass switching transistor, in a switch array module, connected to the differentiated battery unit; and
re-determining a maximum charging current based on a quantity of the remaining battery units, and performing charging on the remaining battery units using the re-determined maximum charging current.

5. The method according to claim 1 , wherein the changing at least a portion of battery units in the parallel battery pack to a series connection, and performing series charging on the battery units comprises:
changing the battery units in the parallel battery pack to an all-series connection by controlling switching transistors in a switch array module to be on or off, and performing all-series charging on the battery units; or
changing the battery units in the parallel battery pack to a series-parallel connection by controlling switching transistors in a switch array module to be on or off, and performing series-parallel charging on the battery units.

6. The method according to claim 1 , wherein after the performing series charging on the battery units, the method further comprises:
monitoring charging statuses of the battery units;
in response to detecting that charging of the battery units is completed, ending charging of the battery units; and
changing the battery units back to a parallel connection; or
changing the battery units to a series connection or a series-parallel connection based on a load power requirement.

7. A fast charging system for a parallel battery pack, comprising:
an alternating current to direct current (AC/DC) conversion module,
a charging control module,
a switch array module, and
a parallel battery pack module, wherein
the AC/DC conversion module is connected to the charging control module, and is configured to convert, to a DC signal, an AC signal provided by an external power supply;
the charging control module is connected to the parallel battery pack module using the switch array module, the parallel battery pack module comprises a plurality of battery units connected in parallel, and the charging control module is configured to:
obtain a maximum charging current allowed by a charging trunk and a charging current required for charging the parallel battery pack module; and when the charging current required for charging the parallel battery pack is greater than the maximum charging current allowed by the charging trunk, control the switch array module to change some or all of battery units in the parallel battery pack module to a series connection, and perform series charging on the battery units by using the direct current signal that is output by the AC/DC conversion module;
obtain charge parameters of the battery units in the parallel battery pack based on charge parameter characteristic curves each of which is indicative of how a charge parameter of a respective battery unit changes with a charge cycle quantity of the battery unit, and determine, based on the charge parameters, whether there is a differentiated battery unit in the parallel battery pack; and
when there is a differentiated battery unit in the parallel battery pack, control the switch array module to change the battery units in the parallel battery pack module to a series-parallel connection, and perform series-parallel charging on the battery units by using the DC signal that is output by the AC/DC conversion module.

8. The fast charging system according to claim 7 , wherein the switch array module comprises a plurality of switching transistors and a plurality of bypass switches, each of the switching transistors is connected to at least one of the battery units, and each of the bypass switches is connected to at least one of the battery units; and the switch array module is configured to:
control, by changing an on or off state of the plurality of switching transistors, the battery units to change between a series connection, a parallel connection, and a series-parallel connection; and
implement charging protection or discharging protection on the battery units by changing an on or off state of the plurality of bypass switches.

9. The fast charging system according to claim 8 , wherein the charging control module comprises a charging power adjustment circuit and a charging monitoring circuit; the charging power adjustment circuit is configured to obtain a charging power requirement of the battery units th

Assignees

• Huawei Tech Co Ltd

Inventors

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

Classifications

• H02J7/62

  against overcurrent · CPC title

• H02J7/575 Primary

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

• H02J7/02

  for charging batteries from AC mains by converters · CPC title

• H02J7/0024 Primary

  Electricity · mapped topic

• H02J7/00304

  Electricity · mapped topic