US-12620818-B2 - Charging and discharging method for series-parallel batteries and series-parallel battery system

Abstract

The present disclosure provides a charging and discharging method for series-parallel batteries applied to a series-parallel battery system including series-parallel batteries and a mainboard, the series-parallel batteries are connected to the mainboard and include at least two batteries that are connected to each other, and the method includes: determining and adjusting a connection mode of each battery of the series-parallel batteries according to a charging or discharging demand type; and charging or discharging the series-parallel batteries according to the connection mode of each battery of the series-parallel batteries. The present disclosure further provides a series-parallel battery system.

Inventors

• Yong Gong

Assignees

• ZTE CORPORATION

Dates

Publication Date

20260505

Application Date

20210520

Priority Date

20200609

Claims (20)

1. 1 . A charging and discharging method for series-parallel battery assembly applied to a series-parallel battery system comprising a series-parallel battery assembly and a mainboard, wherein the series-parallel battery assembly is connected to the mainboard and comprises at least two batteries that are connected to each other, and the method comprises: determining and adjusting a connection mode of each battery of the series-parallel battery assembly according to a charging or discharging demand type; and charging or discharging the series-parallel battery assembly according to the connection mode of each battery of the series-parallel battery assembly, wherein the series-parallel battery assembly at least comprises: a battery combination management circuit, a first cell, a second cell, a first protection circuit, a second protection circuit and a third protection circuit; one battery of the series-parallel battery assembly comprises the first cell, the first protection circuit and the second protection circuit, and another battery of the series-parallel battery assembly comprises the second cell and the third protection circuit, wherein in each battery, the cell stores electric energy, and the protection circuit detects voltages and currents at two ends of the cell so as to perform overcharge protection and over-discharge protection on the cell; and the series-parallel battery system further comprises one switch configured to adjust the connection mode of each battery, and the one switch is disposed inside the series-parallel battery assembly or on the mainboard.
2. 2 . The method of claim 1 , wherein the one switch is disposed inside the series-parallel battery assembly, a first end of the one switch is connected to a first end of the first cell and a first positive terminal of the series-parallel battery assembly, a second end of the one switch is connected to a first end of the second cell and a second positive terminal of the series-parallel battery assembly, and a third end of the one switch is connected to a fourth end of the battery combination management circuit; the first end of the first cell is respectively connected to the first positive terminal of the series-parallel battery assembly, a third end of the first protection circuit, a third end of the second protection circuit and a third end of the battery combination management circuit, and a second end of the first cell is respectively connected to a first end of the first protection circuit and a first end of the second protection circuit; the first end of the second cell is respectively connected to a second end of the first protection circuit, a third end of the third protection circuit, the second positive terminal of the series-parallel battery assembly and a fifth end of the battery combination management circuit, and a second end of the second cell is connected to a first end of the third protection circuit; a first end of the battery combination management circuit is connected to a fourth end of the first protection circuit, a second end of the battery combination management circuit is connected to a fourth end of the second protection circuit, and a sixth end of the battery combination management circuit is connected to a communication terminal of the series-parallel battery assembly; a second end of the third protection circuit is respectively connected to a second end of the second protection circuit and a negative terminal of the series-parallel battery assembly; and the mainboard comprises a charging and discharging management circuit, and the charging and discharging management circuit is connected to the communication terminal of the series-parallel battery assembly.
3. 3 . The method of claim 1 , wherein the one switch is disposed on the mainboard, the mainboard further comprises a charging and discharging management circuit, a first end of the one switch is connected to a first positive terminal of the series-parallel battery assembly, a second end of the one switch is connected to a second positive terminal of the series-parallel battery assembly, a third terminal of the one switch is connected to a first end of the charging and discharging management circuit, and a second end of the charging and discharging management circuit is connected to a communication terminal of the series-parallel battery assembly; a first end of the first cell is respectively connected to the first positive terminal of the series-parallel battery assembly, a third end of the first protection circuit, a third end of the second protection circuit and a third end of the battery combination management circuit, and a second end of the first cell is respectively connected to a first end of the first protection circuit and a first end of the second protection circuit; a first end of the second cell is respectively connected to a second end of the first protection circuit, a third end of the third protection circuit, the second positive terminal of the series-parallel battery assembly and a fifth end of the battery combination management circuit, and a second end of the second cell is connected to a first end of the third protection circuit; a first end of the battery combination management circuit is connected to a fourth end of the first protection circuit, a second end of the battery combination management circuit is connected to a fourth end of the second protection circuit, and a sixth end of the battery combination management circuit is connected to the communication terminal of the series-parallel battery assembly; and a second end of the third protection circuit is respectively connected to a second end of the second protection circuit and a negative terminal of the series-parallel battery assembly.
4. 4 . The method of claim 1 , before the charging the series- parallel battery assembly according to the connection mode of each battery of the series-parallel battery assembly, further comprising: detecting voltages of cells in all the batteries of the series-parallel battery assembly, and determining a maximum value of the voltages; respectively grouping a cell in each battery of the series-parallel battery assembly and a cell corresponding to the maximum value of the voltages to form a group, and respectively calculating a voltage difference between both cells in each group; in response to a voltage difference of at least one group of cells being greater than or equal to a preset first threshold, performing balanced pre-charging on a cell with a smaller voltage in the group, detecting a voltage of the cell subjected to the balanced pre-charging, and stopping the balanced pre-charging of the cell until the voltage difference between both cells in the group is less than the first threshold; and in response to a voltage difference of each group of cells being less than the first threshold, charging the series-parallel battery assembly according to the connection mode of each battery of the series-parallel battery assembly.
5. 5 . The method of claim 1 , further comprising: detecting a voltage of a cell in each battery of the series-parallel battery assembly when the series-parallel battery assembly is charged according to the connection mode of each battery of the series-parallel battery assembly; and in response to a voltage of at least one cell reaching a cut-off voltage and a voltage of at least one cell not reaching the cut-off voltage, performing compensation charging individually on the cell which does not reach the cut-off voltage.
6. 6 . The method of claim 5 , wherein in a case where the connection mode of each battery of the series-parallel battery assembly is a series connection mode, the method further comprises: in response to the voltage of the at least one cell reaching the cut-off voltage and the voltage of the at least one cell not reaching the cut-off voltage, determining whether the cell in each battery of the series-parallel battery assembly is abnormal according to the voltage of the cell, which does not reach the cut-off voltage, at a beginning of the compensation charging and a preset second threshold; and in a case where the connection mode of each battery of the series-parallel battery assembly is a parallel connection mode, after the compensation charging is individually performed on the cell which does not reach the cut-off voltage, the method further comprises: determining whether the cell subjected to the compensation charging in the series-parallel battery assembly is abnormal according to a compensation charging duration of the cell in each battery of the series-parallel battery assembly and a preset third threshold.
7. 7 . The method of claim 6 , wherein the determining whether the cell in each battery of the series-parallel battery assembly is abnormal according to the voltage of the cell, which does not reach the cut-off voltage, at the beginning of the compensation charging and the preset second threshold comprises: calculating a difference between the voltage of the cell, which does not reach the cut-off voltage, at the beginning of the compensation charging and a reference voltage; in response to the difference being greater than or equal to the preset second threshold and the voltage of the cell, which does not reach the cut-off voltage, at the beginning of the compensation charging is less than the reference voltage, determining that a cell which reaches the cut-off voltage first is abnormal; in response to the difference being greater than or equal to the preset second threshold and the voltage of the cell, which does not reach the cut-off voltage, at the beginning of the compensation charging is greater than or equal to the reference voltage, determining that the cell which does not reach the cut-off voltage is abnormal; and in response to the difference being less than the preset second threshold, determining that the cell in each battery of the series-parallel battery assembly is normal.
8. 8 . The method of claim 7 , wherein the reference voltage is an average voltage of cells subjected to previous preset number of times of compensation charging processes at respective beginning of the compensation charging processes, the cells subjected to the compensation charging processes are normal cells, and the compensation charging processes are compensation charging processes in the series connection mode of the batteries; and the method further comprises: in response to the difference being less than the preset second threshold, updating the reference voltage according to the voltage of the cell subjected to a current compensation charging process at the beginning of the compensation charging process.
9. 9 . The method of claim 6 , wherein determining whether the cell subjected to the compensation charging in the series-parallel battery assembly is abnormal according to the compensation charging duration of the cell in each battery of the series-parallel battery assembly and the preset third threshold comprises: calculating a difference between the compensation charging duration of the cell in each battery of the series-parallel battery assembly and a reference duration; in response to the difference being greater than or equal to the preset third threshold and the compensation charging duration is less than the reference duration, determining that the corresponding cell subjected to the compensation charging is abnormal; and in response to the difference being less than the preset third threshold, determining that each cell subjected to the compensation charging in the series-parallel battery assembly is normal.
10. 10 . The method of claim 9 , wherein the reference duration is an average duration of cells subjected to previous preset number of times of compensation charging processes, the cells subjected to the compensation charging processes are normal cells, and the compensation charging processes are compensation charging processes in the parallel connection mode of the batteries; and the method further comprises: in response to the difference being less than the preset third threshold, updating the reference duration according to the compensation charging duration of the cell subjected to a current compensation charging process.
11. 11 . The method of claim 1 , wherein the discharging demand type comprises: parallel output discharging, multi-path independent output discharging and series output discharging; and/or the charging demand type comprises: parallel charging and series charging.
12. 12 . A series-parallel battery system, comprising a series- parallel battery assembly and a mainboard, which are connected to each other, wherein the mainboard comprises a charging and discharging management circuit, the series-parallel battery assembly comprises a battery combination management circuit, and at least two batteries that are connected to each other, the charging and discharging management circuit is connected to the battery combination management circuit and is configured to determine a charging or discharging demand type, and send a corresponding adjustment instruction to the battery combination management circuit according to the charging or discharging demand type; and the battery combination management circuit is configured to adjust a connection mode of the batteries according to the adjustment instruction, and perform charging or discharging on the series-parallel battery assembly according to the connection mode of each battery of the series-parallel battery assembly, wherein the series-parallel battery assembly at least further comprises: a first cell, a second cell, a first protection circuit, a second protection circuit and a third protection circuit; one battery of the series-parallel battery assembly comprises the first cell, the first protection circuit and the second protection circuit, and another battery of the series-parallel battery assembly comprises the second cell and the third protection circuit, wherein in each battery, the cell stores electric energy, and the protection circuit detects voltages and currents at two ends of the cell so as to perform overcharge protection and over-discharge protection on the cell; and the series-parallel battery system further comprises one switch configured to adjust the connection mode of each battery, and the one switch is disposed inside the series-parallel battery assembly or on the mainboard.
13. 13 . The series-parallel battery system of claim 12 , wherein the charging and discharging management circuit is further configured to, before the charging and discharging management circuit performs the charging on the series-parallel battery assembly according to the connection mode of each battery of the series-parallel battery assembly, detect voltages of cells in all the batteries of the series-parallel battery assembly, and determine a maximum value of the voltages; respectively group a cell in each battery of the series-parallel battery assembly and a cell corresponding to the maximum value of the voltages to form a group, and respectively calculate a voltage difference between both cells in each group; in response to the voltage difference of at least one group of cells being greater than or equal to a preset first threshold, perform balanced pre-charging on a cell with a smaller voltage in the group, and detect a voltage of the cell subjected to the balanced pre-charging, and stop the balanced pre-charging of the cell until the voltage difference between both cells in the group is less than the first threshold; and in response to a voltage difference of each group of cells being less than the first threshold, perform the charging on the series-parallel battery assembly according to the connection mode of each battery of the series-parallel battery assembly.
14. 14 . The series-parallel battery system of claim 13 , wherein the charging and discharging management circuit is further configured to detect a voltage of a cell in each battery of the series-parallel battery assembly when the battery combination management circuit performs the charging on the series-parallel battery assembly according to the connection mode of each battery of the series-parallel battery assembly; and in response to a voltage of at least one cell reaching a cut-off voltage and a voltage of at least one cell not reaching the cut-off voltage, instruct the battery combination management circuit to perform compensation charging individually on the cell which does not reach the cut-off voltage.
15. 15 . The series-parallel battery system of claim 14 , wherein, in a case where the connection mode of each battery of the series-parallel battery assembly is a series connection mode, the battery combination management circuit is further configured to, in response to the voltage of the at least one cell reaching the cut-off voltage and the voltage of the at least one cell not reaching the cut-off voltage, determine whether the cell in each battery of the series-parallel battery assembly is abnormal according to the voltage of the cell, which does not reach the cut-off voltage, at a beginning of the compensation charging and a preset second threshold; and in a case where the connection mode of each battery of the series-parallel battery assembly is a parallel connection mode, the charging and discharging management circuit is further configured to, after the compensation charging is individually performed on the cell which does not reach the cut-off voltage, determine whether the cell subjected to the compensation charging in the series-parallel battery assembly is abnormal according to a compensation charging duration of the cell in each battery of the series-parallel battery assembly and a preset third threshold.
16. 16 . The series-parallel battery system of claim 15 , wherein, in a case where the connection mode of each battery of the series-parallel battery assembly is the series connection mode, the battery combination management circuit is configured to calculate a difference between the voltage of the cell, which does not reach the cut-off voltage, at the beginning of the compensation charging and a reference voltage; in response to the difference being greater than or equal to the preset second threshold and the voltage of the cell, which does not reach the cut-off voltage, at the beginning of the compensation charging is less than the reference voltage, determine that a cell which reaches the cut-off voltage first is abnormal; in response to the difference being greater than or equal to the preset second threshold and the voltage of the cell, which does not reach the cut-off voltage, at the beginning of the compensation charging is greater than or equal to the reference voltage, determine that the cell which does not reach the cut-off voltage is abnormal; and in response to the difference being less than the preset second threshold, determine that the cell in each battery of the series-parallel battery assembly is normal.
17. 17 . The series-parallel battery system of claim 16 , wherein the reference voltage is an average voltage of cells subjected to previous preset number of times of compensation charging processes at respective beginning of the compensation charging processes, the cells subjected to the compensation charging processes are normal cells, and the compensation charging processes are compensation charging processes in the series connection mode of the batteries; and the charging and discharging management circuit is further configured to update the reference voltage according to the voltage of the cell subjected to a current compensation charging process at the beginning of the compensation charging, in response to the difference being less than the preset second threshold.
18. 18 . The series-parallel battery system of claim 15 , wherein, in a case where the connection mode of each battery of the series-parallel battery assembly is the parallel connection mode, the battery combination management circuit is configured to calculate a difference between the compensation charging duration of the cell in each battery of the series-parallel battery assembly and a reference duration; in response to the difference being greater than or equal to the preset third threshold and the compensation charging duration is less than the reference duration, determine that the corresponding cell subjected to the compensation charging is abnormal; and in response to the difference being less than the preset third threshold, determine that each cell subjected to the compensation charging in the series-parallel battery assembly is normal.
19. 19 . The series-parallel battery system of claim 18 , wherein the reference duration is an average duration of cells subjected to previous preset number of times of compensation charging processes, the cells subjected to the compensation charging processes are normal cells, and the compensation charging processes are compensation charging processes in the parallel connection mode of the batteries; and the charging and discharging management circuit is further configured to update the reference duration according to the compensation charging duration of the cell subjected to a current compensation charging process, in response to the difference being less than the preset third threshold.
20. 20 . The series-parallel battery system of claim 12 , wherein the discharging demand type comprises: parallel output discharging, multi-path independent output discharging and series output discharging; and/or the charging demand type comprises: parallel charging and series charging.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS The present disclosure claims the priority to the Chinese Patent Application No. 202010518584.7 filed with the CNIPA on Jun. 9, 2020, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to, but is not limited to, the field of battery technology. BACKGROUND Terminals such as mobile phones have become important tools in various aspects of the life such as communication interaction and digital entertainment, and a high-capacity battery is a main measure for improving the battery life of the terminals. The high-capacity battery and the frequent use of the terminals make fast charging become an important aspect in the improvement in user experience. Due to a transmission current limit of 5 A (amperes) of cables, in order to increase charging efficiency and reduce a power transmission loss and a power conversion loss, high voltage charging has become a mainstream option. The transmission method of increasing a voltage and reducing a current can effectively reduce a line transmission loss, but cannot be directly used to charge a battery because the high voltage is not matched with a voltage of the battery. Even in a case where a 5V (volts) power supply is used for charging, the voltage of the 5V power supply needs to be converted to a voltage suitable for the battery with a power conversion chip for charging. SUMMARY In one aspect, the present disclosure provides a charging and discharging method for series-parallel batteries applied to a series-parallel battery system including series-parallel batteries and a mainboard, the series-parallel batteries are connected to the mainboard and include at least two batteries that are connected to each other, and the method includes: determining and adjusting a connection mode of each battery of the series-parallel batteries according to a charging or discharging demand type; and charging or discharging the series-parallel batteries according to the connection mode of each battery of the series-parallel batteries. In the other aspect, the present disclosure further provides a series-parallel battery system, including series-parallel batteries and a mainboard, which are connected to each other, the mainboard includes a charging and discharging management circuit, the series-parallel batteries include a battery combination management circuit, and at least two batteries that are connected to each other, the charging and discharging management circuit is connected to the battery combination management circuit and is configured to determine a charging or discharging demand type, and send a corresponding adjustment instruction to the battery combination management circuit according to the charging or discharging demand type; and the battery combination management circuit is configured to adjust a connection mode of the batteries according to the adjustment instruction, and perform charging or discharging according to the connection mode of the batteries. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a flowchart illustrating a charging and discharging method for series-parallel batteries according to the present disclosure; FIG. 2a is a schematic structural diagram of a series-parallel battery system according to the present disclosure; FIG. 2b is a schematic structural diagram of series-parallel batteries in the series-parallel battery system shown in FIG. 2a; FIG. 3a is a schematic structural diagram of a series-parallel battery system according to the present disclosure; FIG. 3b is a schematic structural diagram of series-parallel batteries in the series-parallel battery system shown in FIG. 3a; FIG. 4 is a flowchart illustrating a balanced pre-charging process according to the present disclosure; FIG. 5 is a flowchart illustrating a compensation charging process according to the present disclosure; FIG. 6 is a flowchart illustrating a process of determining whether a cell is abnormal in a series connection mode of batteries according to the present disclosure; FIG. 7 is a flowchart illustrating a process of determining whether a cell is abnormal in a parallel connection mode of batteries according to the present disclosure; and FIG. 8 is a schematic structural diagram of a series-parallel battery system according to the present disclosure. DETAIL DESCRIPTION OF EMBODIMENTS Exemplary embodiments will be described more fully below with reference to the drawings, but the exemplary embodiments may be embodied in different forms, and should not be interpreted as being limited to the embodiments described herein. Rather, the embodiments are provided to make the present disclosure thorough and complete, and are intended to enable those of ordinary skill in the art to fully understand the scope of the present disclosure. The term “and/or” used herein includes any and all combinations of one or more associated listed items. The terms used herein are merely used to describe specific embodiment