CN116344975A

CN116344975A - Battery pack control method, battery management system, battery pack and electric equipment

Info

Publication number: CN116344975A
Application number: CN202310415981.5A
Authority: CN
Inventors: 叶正民; 杨益; 岳嘉
Original assignee: Hunan Megmit Electric Technology Co ltd
Current assignee: Hunan Megmit Electric Technology Co ltd
Priority date: 2023-04-18
Filing date: 2023-04-18
Publication date: 2023-06-27
Anticipated expiration: 2043-04-18
Also published as: CN116344975B

Abstract

The application discloses a control method of a battery pack, a battery management system, the battery pack and electric equipment. The battery pack comprises at least one first unit and at least one electric core, wherein the first unit is connected with the electric core in a one-to-one correspondence manner, and the method comprises the following steps: acquiring the temperature of each cell in at least one cell; if the temperature of the first battery core in the at least one battery core is greater than or equal to a first temperature threshold value, determining at least one bypass battery core which is in physical contact with the first battery core, and controlling each bypass battery core to discharge to a corresponding first unit so as to reduce the voltage of each bypass battery core; and/or, obtaining the voltage of each cell in the at least one cell; and if the voltage of the second battery core in the at least one battery core is greater than or equal to the first voltage threshold value, controlling the second battery core to discharge to the corresponding first unit so as to reduce the voltage of the second battery core. Through the mode, the probability of thermal runaway of the battery pack can be reduced, and the risk of occurrence of safety accidents is reduced.

Description

Battery pack control method, battery management system, battery pack and electric equipment

Technical Field

The present disclosure relates to the field of battery technologies, and in particular, to a control method of a battery pack, a battery management system, a battery pack, and electric devices.

Background

The battery PACK is also called battery PACK, and generally refers to a combined battery, and mainly refers to processing and assembling of a lithium battery PACK. The battery pack is mainly characterized in that a battery core, a battery protection plate, a battery connecting sheet, label paper and the like are combined and processed into a product required by a customer through a battery pack process. The safety performance of a battery pack is an important index for evaluating the stability of the battery pack, wherein when the battery pack transmits thermal runaway, i.e., when excessive heat is generated inside the battery pack and cannot be controlled, the battery pack may be ignited or even exploded.

However, when the battery pack is out of control, the sampling mode is only to adopt early warning and alarming to remind people to evacuate, and the risk of safety accidents is still high in the mode.

Disclosure of Invention

The application aims to provide a control method of a battery pack, a battery management system, the battery pack and electric equipment, so that the probability of thermal runaway of the battery pack can be reduced, and the risk of occurrence of safety accidents is reduced.

In order to achieve the above object, in a first aspect, the present application provides a control method of a battery pack, the battery pack including at least one first unit and at least one battery cell, the first unit and the battery cell being connected in one-to-one correspondence, the method including:

Acquiring the temperature of each cell in at least one cell;

if the temperature of the first battery core in the at least one battery core is greater than or equal to a first temperature threshold value, determining at least one bypass battery core which is in physical contact with the first battery core, and controlling each bypass battery core to discharge to a corresponding first unit so as to reduce the voltage of each bypass battery core;

and/or the number of the groups of groups,

acquiring the voltage of each cell in at least one cell;

and if the voltage of the second battery core in the at least one battery core is greater than or equal to the first voltage threshold value, controlling the second battery core to discharge to the corresponding first unit so as to reduce the voltage of the second battery core.

In an alternative way, before controlling the discharge of each bypass cell to the corresponding first cell, or before controlling the discharge of the second cell to the corresponding first cell, the method further comprises:

outputting an alarm signal;

and controlling the charge and discharge power of the battery pack to be smaller than a first power threshold.

In an alternative manner, the at least one cell includes a first portion of cells connected in series in sequence and a second portion of cells connected in series in sequence, the first portion of cells being connected in parallel with the second portion of cells.

In an alternative manner, after controlling the charge-discharge power of the battery pack to be less than the first power threshold, the method further comprises:

if the first part of the electric core comprises a first electric core and/or the first part of the electric core comprises a second electric core, acquiring the current of the first part of the electric core;

if the current of the first part of the battery core is larger than a first current threshold value, delaying a first time length, and disconnecting the connection between the first part of the battery core and the second part of the battery core when the first time length is finished;

and if the current of the first part of the battery cells is smaller than or equal to the first current threshold value, disconnecting the first part of the battery cells from the second part of the battery cells.

In an alternative manner, after the controlling the charge-discharge power of the battery pack to be less than the first power threshold, the method further includes:

if the second part of the battery cells comprise the first battery cells and/or the second part of the battery cells comprise the second battery cells, acquiring the current of the second part of the battery cells;

if the current of the second part of the battery cells is larger than a second current threshold value, delaying a second time period, and disconnecting the connection between the first part of the battery cells and the second part of the battery cells when the second time period is over;

And if the current of the second part of the battery cells is smaller than or equal to the second current threshold value, disconnecting the first part of the battery cells from the second part of the battery cells.

In an alternative way, after controlling each bypass cell to discharge to the corresponding first cell, the method further comprises: when the voltage of the bypass battery core is smaller than or equal to a second voltage threshold value, controlling the bypass battery core to stop discharging;

after controlling the second cell to discharge to the corresponding first cell, the method further comprises: and when the voltage of the second battery cell is smaller than or equal to the third voltage threshold value, controlling the second battery cell to stop discharging.

In an alternative manner, after controlling the bypass cell to stop discharging, the method further comprises: stopping outputting the alarm signal when the temperature of the first battery core is smaller than or equal to a second temperature threshold value, wherein the second temperature threshold value is smaller than the first temperature threshold value;

after controlling the second cell to stop discharging, the method further comprises: and stopping outputting the alarm signal when the voltage of the second battery core is smaller than or equal to a fourth voltage threshold, wherein the fourth voltage threshold is larger than or equal to the third voltage threshold and smaller than the first voltage threshold.

In an alternative manner, after stopping outputting the alarm signal when the temperature of the first battery cell is less than or equal to the second temperature threshold, the method further includes: when the temperature of the first battery cell is smaller than or equal to a third temperature threshold value and the voltage of the bypass battery cell is smaller than or equal to a fifth voltage threshold value, controlling the bypass battery cell corresponding to the first unit to charge, wherein the third temperature threshold value is smaller than or equal to the second temperature threshold value;

After stopping outputting the alarm signal when the voltage of the second battery cell is less than or equal to the fourth voltage threshold, the method further comprises: and when the voltage of the second battery cell is smaller than or equal to a sixth voltage threshold, controlling the second battery cell corresponding to the first unit to charge.

In an alternative manner, after controlling the bypass cell corresponding to the first unit to charge, the method further includes: when the electric energy of the first unit is smaller than or equal to a first electric energy threshold value or the voltage of the bypass battery core is larger than or equal to a seventh voltage threshold value, controlling the first unit to stop charging of the corresponding bypass battery core;

after controlling the charging of the second battery cell corresponding to the first unit, the method further comprises: and when the electric energy of the first unit is smaller than the first electric energy threshold value or the voltage of the second battery cell is larger than or equal to the eighth voltage threshold value, controlling the first unit to stop charging the corresponding second battery cell.

In a second aspect, the present application provides a battery management system comprising:

at least one processor and a memory communicatively coupled to the at least one processor, the memory storing instructions executable by the at least one processor, the instructions being executable by the at least one processor to enable the at least one processor to perform the method as described above.

In a third aspect, the present application provides a battery pack comprising at least one cell and a battery management system as described above.

In an alternative mode, the battery pack further comprises at least one first unit and at least one first switch, and the positive electrode and the negative electrode of each battery cell are respectively connected with the positive electrode and the negative electrode of one first unit through one first switch;

when the battery management system controls the two first switches connected with any one of the at least one battery core to be closed, the battery core connected with the closed two first switches discharges to or is charged by the corresponding first unit.

In a fourth aspect, the present application provides a powered device comprising a load and a battery pack as described above, the battery pack being configured to power the load.

In a fifth aspect, the present application provides a non-transitory computer-readable storage medium storing computer-executable instructions that, when executed by a processor, cause the processor to perform a method as described above.

The beneficial effects of this application are: the control method of the battery pack comprises the steps of obtaining the temperature of each battery cell in at least one battery cell. If the temperature of the first battery cell in the at least one battery cell is greater than or equal to the first temperature threshold value, determining at least one bypass battery cell which is in physical contact with the first battery cell, and controlling each bypass battery cell to discharge to a corresponding first unit so as to reduce the voltage of each bypass battery cell, thereby reducing the probability of thermal runaway of the battery pack and being beneficial to reducing the risk of safety accidents. The control method of the battery pack further comprises the step of obtaining the voltage of each battery cell in the at least one battery cell. If the voltage of the second battery core in the at least one battery core is larger than or equal to the first voltage threshold, the second battery core is controlled to discharge to the corresponding first unit so as to reduce the voltage of the second battery core, and the probability of thermal runaway of the battery pack can be reduced so as to reduce the risk of safety accidents.

Drawings

One or at least one embodiment is illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals refer to similar elements and in which the figures do not depict a proportional limitation unless expressly stated otherwise.

Fig. 1 is a schematic structural view of a battery pack according to an embodiment of the present disclosure;

fig. 2 is a schematic structural view of a battery pack according to another embodiment of the present application;

fig. 3 is a schematic structural view of a battery pack according to another embodiment of the present application;

fig. 4 is a schematic structural diagram of an electric device according to an embodiment of the present application;

fig. 5 is a flowchart of a control method of a battery pack according to an embodiment of the present disclosure;

FIG. 6 is a flowchart of a method performed prior to performing step 502 of FIG. 5, as provided by an embodiment of the present application;

FIG. 7 is a flowchart of a method performed after performing step 602 shown in FIG. 6, according to one embodiment of the present application;

FIG. 8 is a flowchart of a method performed after performing step 502 shown in FIG. 5, according to one embodiment of the present application;

FIG. 9 is a flowchart of a method performed after performing step 801 shown in FIG. 8, according to one embodiment of the present application;

FIG. 10 is a flowchart of a method performed after performing step 901 shown in FIG. 9, according to one embodiment of the present application;

FIG. 11 is a flowchart of a method performed after performing step 1001 shown in FIG. 10 according to an embodiment of the present application;

fig. 12 is a flowchart of a control method of a battery pack according to another embodiment of the present application;

fig. 13 is a flowchart of a control method of a battery pack according to still another embodiment of the present application;

fig. 14 is a flowchart of a control method of a battery pack according to still another embodiment of the present application.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a battery pack 100 according to an embodiment of the present disclosure. The battery pack 100 includes the battery management system 20 and at least one battery cell, and the above elements may be connected by a bus or directly. In fig. 1, only one cell is shown as an example, and the cell is the first cell B1.

The first cell B1 is used for storing and supplying electric energy. When the battery pack 100 includes more than two battery cells, the battery cells may be connected in series, connected in parallel, or in a hybrid of series and parallel connection. In some embodiments, any of the at least one battery cells is a rechargeable battery. For example, the first cell B1 may be a lead-acid battery, a nickel-cadmium battery, a nickel-hydrogen battery, a lithium ion battery, a lithium polymer battery, a lithium iron phosphate battery, or the like. The first cell B1 may be repeatedly charged in a recyclable manner.

The battery management system (Battery Management System, BMS) 20 is used for detecting, managing and/or protecting the first cell B1, etc. For example, in some embodiments, the battery management system 20 is configured to obtain the temperature and voltage of any of the at least one battery cells.

The battery management system 20 comprises at least one processor 28 and a memory 27 in communication with the at least one processor 28, wherein the memory 27 may be internal to the battery management system 20 or external to the battery management system 20, or the memory 27 may be a remotely located memory, and the battery management system 20 is connected through a network.

The memory 27 is a non-volatile computer-readable storage medium that can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. The memory 27 may include a storage program area that may store an operating system, at least one application program required for functions, and a storage data area; the storage data area may store data created according to the use of the terminal, etc. In addition, memory 27 may include high-speed random access memory, and may also include non-volatile memory, such as at least one magnetic disk storage device, flash memory device, or other non-volatile solid-state storage device. In some embodiments, memory 27 optionally includes memory located remotely from processor 28, which can be connected to the terminal via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The processor 28 performs various functions of the terminal and processes the data by running or executing software programs and/or modules stored in the memory 27 and invoking the data stored in the memory 27, thereby performing overall monitoring of the terminal, for example, implementing the control method of the battery pack in any of the embodiments of the present application.

The number of processors 28 may be one or more, one processor 28 being illustrated in fig. 1. The processor 28 and the memory 27 may be connected by a bus or otherwise. Processor 28 may include a Central Processing Unit (CPU), digital Signal Processor (DSP), application Specific Integrated Circuit (ASIC), controller, field Programmable Gate Array (FPGA) device, or the like. Processor 28 may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

Referring to fig. 2, fig. 2 is a schematic structural diagram of a battery pack according to an embodiment of the present disclosure. As shown in fig. 2, the battery pack 100 further includes at least one first unit and at least one first switch, and the positive electrode and the negative electrode of each battery cell are connected to the positive electrode and the negative electrode of one first unit through one first switch, respectively.

Wherein, at least one electric core includes first electric core B1, second electric core B2 … N electric core BN. The at least one first unit includes a first unit A1, a second first unit A2 … nth first unit AN. The at least one first switch comprises a first switch S1, a second first switch S2 … mth first switch SM. Wherein M, N is an integer.

The positive electrode of the first cell B1 is connected to the positive electrode of the first unit A1 through a first switch S1, and the negative electrode of the first cell B1 is connected to the negative electrode of the first unit A1 through a second first switch S2; the positive pole of the second electric core B2 is connected to the positive pole of the second first unit A2 through the second first switch S2, the negative pole of the second electric core B2 is connected to the negative pole … of the second first unit A2 through the third first switch S3, the positive pole of the N-th electric core BN is connected to the positive pole of the N-th first unit AN through the N-th first switch SN, and the negative pole of the N-th electric core BN is connected to the negative pole of the N-th first unit AN through the M-th first switch SM. Wherein in this embodiment m=n+1.

Taking as an example two first switches connected to the first cell B1. When the first switch S1 and the second switch S2 are closed, the first cell B1 and the first cell A1 form a loop, and the first cell B1 discharges to the first cell A1 or the first cell A1 discharges to the first cell B1.

In this embodiment, N cells are connected in series in turn. And the positive poles of the N electric cores are the positive poles of the battery pack, and the negative poles of the N electric cores are the negative poles of the battery pack.

Specifically, the first cell B1, the second cell B2 …, the J-th cell BJ, the j+1th cell bj+1, the j+2th cell bj+2 …, and the nth cell BN are sequentially connected in series. The positive electrode (i.e., the third node P3) of the nth cell of the first cell B1, the second cell B2 …, the jth cell bj+1th cell bj+1, the jth+2nd cell bj+ … is the positive electrode of the battery pack 100. The negative electrode (i.e., the fourth node P4) of the nth cell BN of the first cell B1, the second cell B2 …, the jth cell bj+1th cell bj+1, the jth+2nd cell bj+ … is the negative electrode of the battery pack 100. J is an integer < N.

In one embodiment, the battery pack 100 further includes M resistors. The M resistors comprise a first resistor R1, a second resistor R2, a third resistor R3 …, a J-th resistor RJ, a J+1th resistor RJ+1, a J+2th resistor RJ+2, a J+3rd resistor RJ+ …, an Nth resistor RN and an Mth resistor RM.

The Kth resistor in the M resistors is connected between the Kth first switch and the Kth first unit. Specifically, the first resistor R1 is connected between the first switch S1 and the first unit A1, the second resistor R2 is connected between the second first switch S2 and the second first unit A2, and the nth resistor RN is … between the nth first switch SN and the nth first unit AN.

In this embodiment, by providing a resistor connected to each first switch, the resistor can perform a current limiting function, so that it is possible to prevent the first switch or the cell from being damaged due to excessive instantaneous current when each first switch is turned on.

Referring to fig. 3, fig. 3 is a schematic diagram illustrating a circuit structure of a battery pack according to another embodiment of the present disclosure. The battery pack shown in fig. 3 is the same as the battery pack shown in fig. 2 in that the battery pack also includes N cells and N first units, which are described in the above embodiments and are not described here again.

The first difference between the battery pack 100 shown in fig. 3 and the battery pack 100 shown in fig. 2 is that the N cells shown in fig. 3 are connected in series and parallel, and the N cells shown in fig. 2 are all connected in series.

Specifically, in an embodiment, the at least one electric core includes a first part electric core and a second part electric core, the first part electric core is sequentially connected in series, the second part electric core is sequentially connected in series, and the first part electric core is connected in parallel with the second part electric core.

As shown in fig. 3, the first part of the cells comprises J cells and the second part of the cells comprises (N-J) cells. The J-th battery cell comprises a first battery cell B1, a second battery cell B2 and … and a J-th battery cell BJ. The first cell B1 and the second cell B2 and … are connected in series in sequence. The (N-J) th cell includes a (J+1) th cell BJ+1, a (J+2) th cell BJ+2 … Nth cell BN. The (J+1) th electric core BJ+1 and the (J+2) th electric core BJ+2 …) nth electric core BN are sequentially connected in series.

The first part of the battery cells and the second part of the battery cells are connected in parallel. The positive poles of the J electric cores and the positive poles of the (N-J) electric cores are connected to a first node P1, the negative poles of the J electric cores and the negative poles of the (N-J) electric cores are connected to a second node P2, the first node P1 is the positive pole of the battery pack 100, and the second node P2 is the negative pole of the battery pack 100.

The battery pack 100 shown in fig. 3 is different from the battery pack 100 shown in fig. 2 in a second point that m=n+2 in the embodiment shown in fig. 3.

In this embodiment, as shown in fig. 3, two parallel branches of N cells are taken as an example, where the two parallel branches are a first parallel branch including J cells and a second parallel branch including (N-J) cells. M=n+2 at this time. In other embodiments, three or more parallel branches may be provided, so that M varies.

In an embodiment, the battery pack 100 shown in fig. 3 is different from the battery pack 100 shown in fig. 2 in that the battery pack 100 shown in fig. 3 further includes a second switch SA1 and a third switch SA2.

The first end of the second switch SA1 is connected to the first node P1, the first end of the third switch SA2 is connected to the second node P2, the second end of the second switch SA1 is connected to the second end of the third switch SA2, and the second end of the second switch SA1 is the positive electrode of the battery pack 100.

Specifically, the second switch SA1 and the third switch SA2 are used to disconnect the corresponding parallel branches. The second switch SA1 is used for disconnecting the first parallel branch comprising J cells, and the third switch SA2 is used for disconnecting the second parallel branch comprising (N-J) cells. Then, when any one of the N cells is controlled to discharge to the corresponding first unit, the parallel branch where the cell that discharges is disconnected by the second switch SA1 or the third switch SA2, so as to prevent the discharge between the two parallel branches from affecting the cell that is discharging.

In an embodiment, the battery pack 100 shown in fig. 3 is different from the battery pack 100 shown in fig. 2 in that the battery pack 100 shown in fig. 3 further includes a first current detecting unit 30 and a second current detecting unit 40.

The first end of the first current detecting unit 30 is connected to the second end of the second switch SA1, the first end of the second current detecting unit 40 is connected to the second end of the third switch SA2, the second end of the first current detecting unit 30 and the second end of the second current detecting unit 40 are connected to the fifth connection point P5, and the second end of the first current detecting unit 30 (i.e., the fifth connection point P5) is the positive electrode of the battery pack 100.

Specifically, the first current detection unit 30 is configured to detect a current on a first parallel branch including J cells, and the second current detection unit 40 is configured to detect a current on a second parallel branch including (N-J) cells.

In some embodiments, the first unit in any of the embodiments of the present application is an energy storage unit for storing and releasing electrical energy, or the first unit is an energy consumption unit for consuming electrical energy.

When the first unit is an energy storage unit and the first switch connected with any cell is turned on, the corresponding cell can discharge to the first unit, or the first unit discharges to the cell (at this time, the cell is charged). When the first unit is an energy consumption unit, the corresponding battery core can discharge to the first unit when the first switch connected with any battery core is conducted.

For example, in one embodiment, when the first switch S1 is turned on and the second switch S1 is turned on, if the first unit is an energy storage unit, the first cell B1 discharges to the first unit A1 when the voltage of the first cell B1 is greater than the voltage of the first unit A1; when the voltage of the first cell B1 is smaller than the voltage of the first cell A1, the first cell A1 discharges to the first cell B1, and the first cell B1 is charged. If the first cell is an energy consumption cell, the first cell B1 discharges to the first cell A1.

The embodiment of the application also provides electric equipment, as shown in fig. 4, the electric equipment 1 comprises a battery pack 100 and a load 200. The load 200 may be an electrical device in the electrical consumer 1.

The powered device 1 may be any suitable device requiring power from the battery pack 100, such as a drone, an energy storage product, an electric tool, a two-wheeled vehicle, etc.

Referring to fig. 5, fig. 5 is a flowchart of a control method of a battery pack according to an embodiment of the present disclosure. The battery pack comprises at least one first unit and at least one electric core, and the first units are connected with the electric cores in a one-to-one correspondence mode. In some embodiments, the battery pack may be implemented by a circuit structure as shown in fig. 1-3, and specific implementation processes are described in detail in the foregoing embodiments, which are not repeated herein.

As shown in fig. 5, the control method of the battery pack includes the steps of:

step 501: the temperature of each cell of the at least one cell is obtained.

Step 502: if the temperature of the first battery core in the at least one battery core is greater than or equal to a first temperature threshold value, determining at least one bypass battery core which is in physical contact with the first battery core, and controlling each bypass battery core to discharge to a corresponding first unit so as to reduce the voltage of each bypass battery core.

The first temperature threshold is a preset temperature threshold, which may be set according to an actual application situation, which is not specifically limited in the embodiment of the present application.

The number of the first battery cells can be multiple or only one. Taking the battery pack shown in fig. 2 as an example, only the first cell B1 of the N cells may have a temperature greater than or equal to the first temperature threshold, and both the first cell B1 and the second cell B2 may have a temperature greater than or equal to the first temperature threshold.

The cells having physical contact with each first cell are bypass cells. I.e. for one first cell there may be one or more bypass cells. For example, in one embodiment, the first cell is rectangular, there is one cell in physical contact with the first cell on each of four sides of the first cell, and there are a total of four bypass cells for the first cell.

Specifically, when the temperature of the first battery cell is greater than or equal to the first temperature threshold, it may be determined that the temperature of the first battery cell is too high and thermal runaway of the battery pack may occur. At this time, each bypass cell is controlled to discharge to the corresponding first cell to reduce the voltage of each bypass cell. Taking the battery pack shown in fig. 2 as an example, if the temperature of the first cell B1 (i.e., the first cell) is greater than or equal to the first temperature threshold, and there is physical contact between the J-th cell BJ and the first cell B1, i.e., the J-th cell BJ is a bypass cell. At this time, the J-th first switch SJ and the j+1th first switch sj+1 are both controlled to be closed, and the J-th battery cell BJ discharges to the J-th first unit AJ.

Therefore, on one hand, due to the fact that the voltage of the bypass battery core is reduced, the high temperature of the bypass battery core caused by the fact that the high temperature of the first battery core is transmitted to the bypass battery core can be effectively avoided, the probability of thermal runaway of the battery pack can be reduced, and the risk of occurrence of safety accidents is reduced. On the other hand, even if the first battery cell is out of control due to the fact that the temperature is too high, and the battery pack fires or even explodes, only the energy of the fires or explodes is the energy of the first battery cell at the moment, and the risk of safety accidents is small.

In one embodiment, as shown in fig. 6, before performing the process of controlling the discharging of each bypass cell to the corresponding first cell in step 502, the control method of the battery pack further includes the following steps:

step 601: and outputting an alarm signal.

Step 602: and controlling the charge and discharge power of the battery pack to be smaller than a first power threshold.

The first power threshold is a preset power value, which may be set according to an actual application situation, which is not specifically limited in the embodiment of the present application. The charge and discharge power refers to charge power and discharge power.

Specifically, when the temperature of the first battery cell is greater than or equal to the first temperature threshold value in at least one battery cell, an alarm signal is output at first to remind a user, so that the user can be helped to timely process abnormality and even timely evacuate, and the risk of safety accidents is reduced. Meanwhile, since the bypass battery cells need to be controlled to discharge later, the charging and discharging processes of all the battery cells need to be stopped first, and the battery pack is controlled to have charging and discharging power smaller than a first power threshold.

In an embodiment, if the cells in the at least one cell are connected in parallel, for example, a battery pack as shown in fig. 3, where the at least one cell includes a first portion of cells and a second portion of cells, the first portion of cells are sequentially connected in series, the second portion of cells are sequentially connected in series, and the first portion of cells are connected in parallel with the second portion of cells. In this case, after performing the process of controlling the charge and discharge power of the battery pack to be less than the first power threshold in step 602, the control method of the battery pack further includes the steps of:

step 701: if the first part of the electric core comprises a first electric core and/or the first part of the electric core comprises a second electric core, acquiring the current of the first part of the electric core;

step 702: and if the current of the first part of the battery cells is larger than the first current threshold value, delaying the first time period, and disconnecting the connection between the first part of the battery cells and the second part of the battery cells when the first time period is over.

Step 703: and if the current of the first part of the battery cells is smaller than or equal to the first current threshold value, disconnecting the first part of the battery cells from the second part of the battery cells.

The first current threshold is a preset current value, which may be set according to an actual application situation, which is not specifically limited in the embodiment of the present application.

In this embodiment, the first portion of the battery cells includes at least one of the first battery cells and the second battery cells, and then the current of the first portion of the battery cells, that is, the current of the branch where the first portion of the battery cells is located, is obtained.

And then, if the current of the first part of the battery cells is smaller than or equal to the first current threshold value, determining that the current almost exists on the first part of the battery cells, and directly disconnecting the first part of the battery cells from the second part of the battery cells. Taking the battery pack shown in fig. 3 as an example, assuming that the first cell B1 is a first cell, and the current on the J-th cell BJ of the first cell B1 and the second cell B2 … is less than or equal to the first current threshold, the second switch SA1 is controlled to be turned off so as to disconnect the first portion of cells from the second portion of cells.

And if the current of the first part of the battery cells is larger than the first current threshold value, determining that the current exists on the first part of the battery cells. If the connection between the first part of the battery cells and the second part of the battery cells is directly disconnected, the switch for disconnecting the connection between the first part of the battery cells and the second part of the battery cells may be damaged, a period of time is needed to wait for the first time, and the period of time corresponds to the first time. During the first time period, the current on the first part of the battery cells may decrease, but even if the current on the first part of the battery cells is not reduced to be less than or equal to the first current threshold value at the end of the first time period, the connection between the first part of the battery cells and the second part of the battery cells needs to be disconnected due to safety. Taking the battery pack shown in fig. 3 as an example, assuming that the first electric core B1 is the first electric core, and the current on the J-th electric core BJ of the first electric core B1 and the second electric core B2 … is greater than the first current threshold, the first time is delayed first, and the second switch SA1 is controlled to be turned off at the moment when the first time is ended, so as to disconnect the connection between the first part of electric cores and the second part of electric cores.

It can be understood that in this embodiment, the first portion of the battery cells includes at least one of the first battery cells and the second battery cells to determine that the branch where the first portion of the battery cells is the branch where the abnormal battery cells (including the first battery cells and the second battery cells) are located.

In other embodiments, if at least one of the first battery cell and the second battery cell may also exist in the second portion battery cell, the branch where the second portion battery cell is located is the branch where the abnormal battery cell is located. Specifically, after performing the process of controlling the charge and discharge power of the battery pack to be less than the first power threshold in step 602, the control method of the battery pack further includes the following steps: and if the second part of the battery cells comprise the first battery cells and/or the second part of the battery cells comprise the second battery cells, acquiring the current of the second part of the battery cells. And if the current of the second part of the battery cells is larger than the second current threshold value, delaying the second time, and disconnecting the connection between the first part of the battery cells and the second part of the battery cells when the second time is over. And if the current of the second part of the battery cells is smaller than or equal to the second current threshold value, disconnecting the first part of the battery cells from the second part of the battery cells.

The second current threshold is a preset current value, the second duration is a preset duration, the second current threshold and the second duration can be set according to actual application conditions, and the embodiment of the application is not particularly limited.

The specific implementation of this embodiment may refer to the detailed description of fig. 7, and will not be described here.

In another embodiment, as shown in fig. 8, after performing the process of controlling the discharge of each bypass cell to the corresponding first cell in step 502, the discharging method of the battery pack further includes the steps of:

step 801: and when the voltage of the bypass cell is smaller than or equal to the second voltage threshold, controlling the bypass cell to stop discharging.

The second voltage threshold is a preset voltage value, which may be set according to an actual application situation, which is not specifically limited in the embodiment of the present application.

The voltage of the bypass cell being less than or equal to the second voltage threshold may determine that the discharging process of the bypass cell has ended, and at this time, the bypass cell is controlled to stop discharging to be performed for subsequent operations. Taking the battery pack shown in fig. 2 as an example, assuming that the first battery cell B1 is a bypass battery cell, if the voltage of the first battery cell B1 is less than or equal to the second voltage threshold, the first switch S1 and the second first switch S2 are controlled to be turned off, so as to control the first battery cell B1 to stop discharging.

In one embodiment, as shown in fig. 9, after performing the process of controlling the bypass cell to stop discharging in step 801, the discharging method of the battery pack further includes the steps of:

step 901: and stopping outputting the alarm signal when the temperature of the first battery cell is less than or equal to the second temperature threshold value.

Wherein the second temperature threshold is less than the first temperature threshold. The second temperature threshold is a preset temperature value, which can be set according to practical application conditions, and the embodiment of the application is not particularly limited.

If the temperature of the first battery cell is reduced to be less than or equal to the second temperature threshold value, it can be determined that the risk of thermal runaway of the first battery cell caused by the overhigh temperature is low, and at the moment, the output of the alarm signal can be stopped.

In one embodiment, as shown in fig. 10, after the process of stopping the output of the alarm signal in step 901 is performed, the discharging method of the battery pack further includes the steps of:

step 1001: and when the temperature of the first battery core is smaller than or equal to a third temperature threshold value and the voltage of the bypass battery core is smaller than or equal to a fifth voltage threshold value, controlling the bypass battery core corresponding to the first unit to charge.

Wherein the third temperature threshold is less than or equal to the second temperature threshold. The third temperature threshold is a preset temperature value, the fifth voltage threshold is a preset voltage value, the third temperature threshold and the fifth voltage threshold can be set according to practical application conditions, and the embodiment of the application is not particularly limited.

In this embodiment, it is first determined that the temperature of the first cell is less than or equal to the third temperature threshold to determine that the temperature of the first cell not only results in a lower risk of thermal runaway, but also that the temperature of the first cell is already low enough to be charged normally. In other words, if the temperature of the first battery cell is less than or equal to the second temperature threshold but greater than the third temperature threshold, the temperature of the first battery cell may rise to be greater than the second temperature threshold again after charging, and even greater than the first temperature threshold, so that thermal runaway may occur. Then, by confirming that the temperature of the first battery cell decreases to be less than or equal to the third temperature threshold value, the risk of thermal runaway caused by the temperature of the first battery cell rising again when the first battery cell is charged can be reduced.

Meanwhile, it is also determined that the voltage of the bypass cell is less than or equal to the fifth voltage threshold, so as to determine that the voltage of the bypass cell is lower and in a state that can be charged. In this case, the first unit is operated to discharge to the bypass cell based on the stored electric energy thereof, i.e., the bypass cell is charged, thereby realizing the reuse of the electric energy and being beneficial to saving the energy consumption. It is understood that in this embodiment, the first unit is used as an energy storage unit.

Taking the battery pack shown in fig. 2 as an example, when the temperature of the first battery cell is less than or equal to the third temperature threshold and the voltage of the bypass battery cell (assumed to be the first battery cell B1) is less than or equal to the fifth voltage threshold, the first switch S1 and the second first switch S2 are controlled to be closed, and the first unit A1 charges the first battery cell B1.

In another embodiment, when the temperature of the first battery cell is less than or equal to the third temperature threshold, if the voltage of the bypass battery cell is greater than the fifth voltage threshold, it may be determined that the bypass battery cell does not need to be charged, and at this time, the bypass battery cell may be controlled to perform normal use, that is, the bypass battery cell may perform normal discharge operation. And when the voltage of the bypass cell is smaller than or equal to a fifth voltage threshold, charging the bypass cell corresponding to the first unit is controlled.

In one embodiment, as shown in fig. 11, after performing the process of controlling the charging of the bypass cell corresponding to the first unit in step 1001, the discharging method of the battery pack further includes the following steps:

step 1101: and when the electric energy of the first unit is smaller than or equal to a first electric energy threshold value or the voltage of the bypass battery core is larger than or equal to a seventh voltage threshold value, controlling the first unit to stop charging the corresponding bypass battery core.

The first power threshold is a preset power value, the seventh voltage threshold is a preset voltage value, and the seventh voltage threshold of the first power threshold can be set according to practical application conditions.

Specifically, when the power of the first unit is less than or equal to the first power threshold, it may be determined that the first unit is insufficient to charge the bypass battery, and at this time, the first unit may be controlled to stop charging the corresponding bypass battery. When the voltage of the bypass cell is greater than or equal to the seventh voltage threshold, it may be determined that the bypass cell has been charged to the set upper limit voltage, and in order to prevent the bypass cell from being overcharged, the first unit needs to be controlled to stop charging the corresponding bypass cell.

Referring to fig. 12, fig. 12 is a flowchart of a control method of a battery pack according to another embodiment of the present disclosure. As shown in fig. 12, the control method of the battery pack includes the steps of:

first, the temperature of each cell is obtained at a time. Judging whether a first battery cell with the temperature not less than T1 exists, wherein T1 corresponds to the first temperature threshold in the embodiment. If the first battery core exists, an alarm signal is output, and the charge and discharge power of the battery pack is controlled to be smaller than a first power threshold value, so that the charge or discharge of each battery core in the battery pack is stopped. And then determining the bypass cell and controlling the bypass cell to discharge to the corresponding first unit. Then, whether the voltage of the bypass cell is less than or equal to V2 is judged, and V2 corresponds to the second voltage threshold in the embodiment. If the voltage of the bypass cell is larger than V2, the bypass cell is kept to be controlled to discharge to the corresponding first unit. And controlling the bypass cell to stop discharging until the voltage of the bypass cell is less than or equal to V2. And then judging whether the temperature of the first battery cell is less than or equal to T2, wherein T2 corresponds to the second temperature threshold in the embodiment. If the temperature of the first battery cell is more than T2, the temperature detection of each battery cell is kept. And stopping outputting the alarm signal until the temperature of the first battery cell is less than or equal to T2. Then, it is determined whether the temperature of the first cell is equal to or less than T3, and T3 corresponds to the third temperature threshold in the above embodiment. If the temperature of the first battery cell is more than T3, the temperature detection of each battery cell is kept. And further judging whether the voltage of the bypass cell is less than or equal to V5 or not until the temperature of the first cell is less than or equal to T3, wherein V5 corresponds to the fifth voltage threshold in the embodiment. If the voltage of the bypass cell is greater than V5, the battery pack can be used normally. And controlling the bypass battery cell corresponding to the first unit to charge until the voltage of the bypass battery cell is less than or equal to V5. And then judging whether the first unit or the bypass cell meets a preset condition, wherein the preset condition comprises that the electric energy of the first unit is smaller than or equal to a first electric energy threshold value or that the voltage of the bypass cell is larger than or equal to a seventh voltage threshold value. And if the electric energy of the first unit is kept larger than the first electric energy threshold value and the voltage of the bypass battery core is kept smaller than the seventh voltage threshold value, the corresponding bypass battery core of the first unit is kept to be charged. And controlling the first unit to stop charging the corresponding bypass battery cell until the electric energy of the first unit is smaller than or equal to a first electric energy threshold value or the voltage of the bypass battery cell is larger than or equal to a seventh voltage threshold value. Finally, the battery can be used normally.

It should be noted that the method steps shown in fig. 12 are applicable to the battery pack shown in fig. 1 to 3. In addition, for the battery pack shown in fig. 3, the method steps shown in fig. 7 may be added between the step of controlling the charge/discharge power of the battery pack to be smaller than the first power threshold and the step of determining the bypass cell and controlling the bypass cell to discharge to the corresponding first cell. The method steps shown in fig. 7 are described in detail in the foregoing embodiments, and are not described herein again.

Referring to fig. 13, fig. 13 is a flowchart of a control method of a battery pack according to another embodiment of the present disclosure. In some embodiments, the battery pack may be implemented by a circuit structure as shown in fig. 1-3, and specific implementation processes are described in detail in the foregoing embodiments, which are not repeated herein.

As shown in fig. 13, the control method of the battery pack includes the steps of:

step 1301: the voltage of each cell in the at least one cell is obtained.

Step 1302: and if the voltage of the second battery core in the at least one battery core is greater than or equal to the first voltage threshold value, controlling the second battery core to discharge to the corresponding first unit so as to reduce the voltage of the second battery core.

The first voltage threshold is a preset voltage value, which may be set according to an actual application situation, which is not specifically limited in the embodiment of the present application.

The number of the second battery cells can be more than one, or only one. Taking the battery pack shown in fig. 2 as an example, only the voltage of the first cell B1 of the N cells may be greater than or equal to the first voltage threshold, or the voltages of the first cell B1 and the second cell B2 may be greater than or equal to the first voltage threshold.

Specifically, when the voltage of the second cell is greater than or equal to the first voltage threshold, it may be determined that the voltage of the second cell is too high and may cause thermal runaway of the battery pack. At this time, the voltage of the second cell is reduced by controlling the second cell to discharge to the corresponding first cell. Taking the battery pack shown in fig. 2 as an example, if the voltage of the first cell B1 (i.e., the second cell) is greater than or equal to the first voltage threshold, the first switch S1 and the second first switch S2 are controlled to be closed, and the first cell B1 discharges to the first unit A1.

Therefore, the voltage of the second battery core is reduced, so that the situation that the temperature is too high due to the fact that the voltage of the second battery core is too high can be effectively avoided, the probability of thermal runaway of the battery pack can be reduced, and the risk of occurrence of safety accidents is reduced.

In an embodiment, the method for controlling the battery pack may further include the method steps shown in fig. 6 and 7 before performing the process of controlling the second cell to discharge to the corresponding first cell in step 1302. The steps of the method shown in fig. 6 and fig. 7 are described in detail in the above embodiments, and are not repeated here.

In one embodiment, after performing the process of controlling the discharge of each bypass cell to the corresponding first cell in step 1302, the discharging method of the battery pack further includes the steps of: and when the voltage of the second battery cell is smaller than or equal to the third voltage threshold value, controlling the second battery cell to stop discharging.

The third voltage threshold is a preset voltage value, which may be set according to an actual application situation, which is not specifically limited in the embodiment of the present application.

The voltage of the second battery cell is smaller than or equal to the third voltage threshold value, and it can be determined that the discharging process of the second battery cell is finished, and the second battery cell is controlled to stop discharging at the moment so as to be ready for executing subsequent operations. Taking the battery pack shown in fig. 2 as an example, assuming that the first battery cell B1 is the second battery cell, if the voltage of the first battery cell B1 is less than or equal to the third voltage threshold, the first switch S1 and the second first switch S2 are controlled to be turned off, so as to control the first battery cell B1 to stop discharging.

In one embodiment, after performing the step of controlling the second cell to stop discharging, the discharging method of the battery pack further includes the steps of: and stopping outputting the alarm signal when the voltage of the second battery cell is smaller than or equal to the fourth voltage threshold value.

The fourth voltage threshold is greater than or equal to the third voltage threshold and less than the first voltage threshold. The fourth voltage threshold is a preset voltage value, which may be set according to an actual application situation, which is not specifically limited in the embodiment of the present application.

If the voltage of the second battery core is reduced to be less than or equal to the fourth voltage threshold value, it can be determined that the risk of thermal runaway of the first battery core caused by the overlarge voltage is low, and the output of the alarm signal can be stopped at the moment.

In one embodiment, after the step of stopping outputting the alarm signal when the voltage of the second cell is less than or equal to the fourth voltage threshold is performed, the discharging method of the battery pack further includes the steps of: and when the voltage of the second battery cell is smaller than or equal to a sixth voltage threshold, controlling the second battery cell corresponding to the first unit to charge.

The sixth voltage threshold is a preset voltage value, and the sixth voltage threshold may be set according to an actual application situation, which is not specifically limited in the embodiment of the present application.

In this embodiment, the voltage of the second cell is determined to be low by determining that the voltage of the second cell is less than or equal to the sixth voltage threshold, in a state that can be charged. In this case, the first unit is operated to discharge the second cell based on the stored electric energy thereof, i.e., the second cell is charged, thereby realizing the reuse of the electric energy, which is advantageous for saving energy consumption. It is understood that in this embodiment, the first unit is used as an energy storage unit.

Taking the battery pack shown in fig. 2 as an example, when the voltage of the second battery cell (assumed to be the first battery cell B1) is less than or equal to the sixth voltage threshold, the first switch S1 and the second first switch S2 are controlled to be both closed, and the first unit A1 charges the first battery cell B1.

In another embodiment, when the voltage of the second battery cell is greater than the sixth voltage threshold, it may be determined that the second battery cell does not need to be charged, and at this time, the second battery cell may be controlled to perform normal use, that is, the second battery cell performs normal discharging operation. And when the voltage of the second battery cell is smaller than or equal to a sixth voltage threshold, charging the second battery cell corresponding to the first unit is controlled.

In one embodiment, after performing the step of controlling the charging of the second battery cell corresponding to the first unit, the discharging method of the battery pack further includes the steps of: and when the electric energy of the first unit is smaller than the first electric energy threshold value or the voltage of the second battery cell is larger than or equal to the eighth voltage threshold value, controlling the first unit to stop charging the corresponding second battery cell.

The first power threshold is a preset power value, the eighth voltage threshold is a preset voltage value, and the eighth voltage threshold of the first power threshold can be set according to practical application conditions.

Specifically, when the power of the first unit is less than or equal to the first power threshold, it may be determined that the first unit is insufficient to charge the second battery cell, and at this time, the first unit may be controlled to stop charging the corresponding second battery cell. When the voltage of the second battery cell is greater than or equal to the eighth voltage threshold, it can be determined that the second battery cell is charged to the set upper limit voltage, and in order to prevent the second battery cell from being overcharged, the first unit needs to be controlled to stop charging the corresponding second battery cell.

Referring to fig. 14, fig. 14 is a flowchart illustrating a control method of a battery pack according to another embodiment of the present disclosure. As shown in fig. 14, the control method of the battery pack includes the steps of:

first, the voltage of each cell is obtained at a time. Judging whether a second battery cell with the voltage not less than V1 exists or not, wherein V1 corresponds to the first voltage threshold in the embodiment. If the second battery core exists, an alarm signal is output, and the charge and discharge power of the battery pack is controlled to be smaller than the first power threshold value, so that the charge or discharge of each battery core in the battery pack is stopped. And then controlling the second battery cell to discharge to the corresponding first unit. Then, it is determined whether the voltage of the second cell is less than or equal to V3, where V3 corresponds to the third voltage threshold in the above embodiment. If the voltage of the second battery cell is larger than V3, the second battery cell is kept to be controlled to discharge to the corresponding first unit. And controlling the second battery cell to stop discharging until the voltage of the second battery cell is less than or equal to V3. Then, whether the voltage of the second battery cell is less than or equal to V4 is judged, and V4 corresponds to the fourth voltage threshold in the embodiment. If the voltage of the second battery cell is more than V4, the voltage detection of each battery cell is kept. And stopping outputting the alarm signal until the voltage of the second battery cell is less than or equal to V4. Then, it is determined whether the voltage of the second cell is less than or equal to V6, V6 corresponding to the sixth voltage threshold in the above embodiment. If the voltage of the second battery cell is greater than V6, the battery pack can be used normally. And controlling the second battery cell corresponding to the first unit to charge until the voltage of the second battery cell is less than or equal to V6. And then judging whether the first unit or the second battery cell meets a preset condition, wherein the preset condition comprises that the electric energy of the first unit is smaller than or equal to a first electric energy threshold value or that the voltage of the second battery cell is larger than or equal to an eighth voltage threshold value. And if the electric energy of the first unit is kept larger than the first electric energy threshold value and the voltage of the second battery cell is kept smaller than the eighth voltage threshold value, the charging of the second battery cell corresponding to the first unit is kept and controlled. And controlling the first unit to stop charging the corresponding second battery cell until the electric energy of the first unit is smaller than or equal to the first electric energy threshold value or the voltage of the second battery cell is larger than or equal to the eighth voltage threshold value. Finally, the battery can be used normally.

It should be noted that the method steps shown in fig. 14 are applicable to the battery pack shown in fig. 1 to 3. In addition, for the battery pack shown in fig. 3, the method shown in fig. 7 may be added between the step of controlling the charge/discharge power of the battery pack to be smaller than the first power threshold and the step of controlling the second cell to discharge to the corresponding first cell. The method steps shown in fig. 7 are described in detail in the foregoing embodiments, and are not described herein again.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; the technical features of the above embodiments or in the different embodiments may also be combined under the idea of the present application, the steps may be implemented in any order, and there are many other variations of the different aspects of the present application as described above, which are not provided in details for the sake of brevity; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for controlling a battery pack, wherein the battery pack includes at least one first unit and at least one battery cell, the first unit and the battery cell are connected in a one-to-one correspondence, the method comprising:

acquiring the temperature of each cell in the at least one cell;

and/or the number of the groups of groups,

acquiring the voltage of each cell in the at least one cell;

2. The method of claim 1, wherein prior to said controlling each bypass cell to discharge to a corresponding first cell or prior to said controlling a second cell to discharge to a corresponding first cell, the method further comprises:

outputting an alarm signal;

3. The method of claim 2, wherein the at least one cell comprises a first portion of cells connected in series in sequence and a second portion of cells connected in series in sequence, the first portion of cells connected in parallel with the second portion of cells.

4. The method of claim 3, wherein after said controlling the charge-discharge power of the battery pack to be less than a first power threshold, the method further comprises:

if the first part of the battery cells comprise the first battery cells and/or the first part of the battery cells comprise the second battery cells, acquiring the current of the first part of the battery cells;

if the current of the first part of the battery cells is larger than a first current threshold value, delaying a first time length, and disconnecting the connection between the first part of the battery cells and the second part of the battery cells when the first time length is over;

5. The method of claim 3, wherein after said controlling the charge-discharge power of the battery pack to be less than a first power threshold, the method further comprises:

6. The method of claim 1, wherein after said controlling each bypass cell to discharge to a corresponding first cell, the method further comprises: when the voltage of the bypass battery core is smaller than or equal to a second voltage threshold value, controlling the bypass battery core to stop discharging;

after the controlling the second cells to discharge to the corresponding first cells, the method further comprises: and when the voltage of the second battery cell is smaller than or equal to a third voltage threshold value, controlling the second battery cell to stop discharging.

7. The method of claim 6, wherein after said controlling said bypass cell to stop discharging, said method further comprises: stopping outputting an alarm signal when the temperature of the first battery cell is smaller than or equal to a second temperature threshold value, wherein the second temperature threshold value is smaller than the first temperature threshold value;

after the controlling the second cell to stop discharging, the method further comprises: and stopping outputting the alarm signal when the voltage of the second battery core is smaller than or equal to a fourth voltage threshold, wherein the fourth voltage threshold is larger than or equal to the third voltage threshold and smaller than the first voltage threshold.

8. The method of claim 7, wherein after stopping outputting the alarm signal when the temperature of the first cell is less than or equal to a second temperature threshold, the method further comprises: when the temperature of the first battery core is smaller than or equal to a third temperature threshold value and the voltage of the bypass battery core is smaller than or equal to a fifth voltage threshold value, controlling the bypass battery core corresponding to the first unit to charge, wherein the third temperature threshold value is smaller than or equal to a second temperature threshold value;

After stopping outputting the alarm signal when the voltage of the second battery cell is less than or equal to a fourth voltage threshold, the method further includes: and when the voltage of the second battery cell is smaller than or equal to a sixth voltage threshold, controlling the second battery cell corresponding to the first unit to charge.

9. The method of claim 8, wherein after said controlling the corresponding bypass cell charge of the first cell, the method further comprises: when the electric energy of the first unit is smaller than or equal to a first electric energy threshold value or the voltage of the bypass battery core is larger than or equal to a seventh voltage threshold value, controlling the first unit to stop charging of the corresponding bypass battery core;

after the controlling the charging of the second battery cell corresponding to the first unit, the method further comprises: and when the electric energy of the first unit is smaller than the first electric energy threshold value or the voltage of the second battery cell is larger than or equal to an eighth voltage threshold value, controlling the first unit to stop charging the corresponding second battery cell.

10. A battery management system, comprising:

at least one processor and a memory communicatively coupled to the at least one processor, the memory storing instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-9.

11. A battery pack comprising at least one cell and the battery management system of claim 10.

12. The battery pack according to claim 11, further comprising at least one first unit and at least one first switch, the positive and negative poles of each cell being connected to the positive and negative poles of one first unit through one first switch, respectively;

when the battery management system controls the two first switches connected with any one of the at least one electric core to be closed, the electric core connected with the two closed first switches discharges to or charges by the corresponding first unit.

13. A powered device comprising a load and the battery pack of claim 12 for powering the load.