CN112531798A

CN112531798A - Battery cell balancing method and battery management system

Info

Publication number: CN112531798A
Application number: CN201910883452.1A
Authority: CN
Inventors: 吴军
Original assignee: Shanghai Dupu New Energy Technology Co ltd
Current assignee: Shanghai Dupu New Energy Technology Co ltd
Priority date: 2019-09-18
Filing date: 2019-09-18
Publication date: 2021-03-19

Abstract

The invention provides a battery cell balancing method and a battery management system, wherein the method comprises the following steps: acquiring the cell equilibrium temperature of the automobile and the cell states of all the cells when the automobile is started; determining whether the automobile needs to be subjected to cell balancing or not based on the cell balancing temperature and the cell state of each cell; if the automobile needs to perform cell balancing, determining the to-be-balanced cell in all the cells by using the voltage of each cell; and balancing all the electric cores to be balanced. In the scheme, whether the automobile needs to be subjected to battery cell equalization is determined according to the battery cell equalization temperature and the battery cell state when the automobile is in a starting state. If the battery cells to be balanced need to be determined and balanced, the battery cells to be balanced are prevented from being under-voltage caused by self-awakening of the battery management system for multiple times after the automobile is flameout, normal starting of the automobile is guaranteed, and use experience of the automobile is improved.

Description

Battery cell balancing method and battery management system

Technical Field

The invention relates to the technical field of data processing, in particular to a battery cell balancing method and a battery management system.

Background

With the popularization of automobiles and the development of scientific technology, the electrification degree of automobiles is higher and higher, and the protection of automobile battery cores is also more and more important.

In order to protect the battery cell of the automobile, the battery cell of the automobile needs to be subjected to equalization processing. The current cell balancing mode generally adopts a static balancing strategy, and the specific mode is as follows: after the automobile is shut down, a Battery Management System (BMS) wakes up once every a period of time to check whether the cells need to be balanced, and discharges the cells needing to be balanced. But BMS is from awakening up and need consuming the electric quantity, and when the car stood for a long time not, BMS was awaken up and carried out the battery that the equilibrium can make the car under-voltage to electric core many times from awakening up to lead to the unable normal start of car, seriously influence the car and use experience.

Disclosure of Invention

In view of this, the embodiment of the invention provides a cell balancing method and a battery management system, so as to solve the problem that the existing cell balancing strategy easily causes that an automobile cannot be started normally, thereby seriously affecting the use experience of the automobile.

In order to achieve the above purpose, the embodiments of the present invention provide the following technical solutions:

the first aspect of the embodiment of the invention discloses a battery cell balancing method, which comprises the following steps:

the method comprises the steps of obtaining the cell equilibrium temperature of the automobile and the cell states of all cells, wherein the automobile is in a starting state, and the cell states comprise: voltage and temperature of the cell;

determining whether the automobile needs to be subjected to cell balancing or not based on the cell balancing temperature and the cell state of each cell;

if the automobile needs to perform cell balancing, determining the to-be-balanced cell in all the cells by using the voltage of each cell;

and balancing all the electric cores to be balanced.

Preferably, the determining whether the vehicle needs to perform cell balancing based on the cell balancing temperature and the cell state of each cell includes:

judging whether the automobile meets a battery cell balancing condition, wherein the battery cell balancing condition comprises the following steps: the difference value of the highest voltage and the lowest voltage in the voltages of all the battery cells is greater than a voltage threshold value, each battery cell has no fault, the cell equilibrium temperature is within the preset temperature range, and when the current of each battery cell is a preset current value, the voltage change value of each battery cell within preset time is within a preset change range, wherein whether the battery cell has a fault or not is determined based on the state of the battery cell;

and if the automobile meets the battery cell balancing condition, determining that the automobile needs to be subjected to battery cell balancing.

Preferably, the determining whether the vehicle needs to perform cell balancing based on the cell state and the voltage of each cell includes:

acquiring the highest voltage and the lowest voltage in the voltages of all the battery cells;

judging whether the difference value of the highest voltage and the lowest voltage is greater than a voltage threshold value;

if the difference value is larger than the threshold value, judging whether each battery cell has a fault or not based on the battery cell state of each battery cell;

if each battery cell has no fault, judging whether the battery cell equilibrium temperature corresponding to the automobile is within a preset temperature range;

if the cell equilibrium temperature is within the preset temperature range, when the current of each cell is a preset current value, judging whether the voltage change value of each cell within a preset time is within a preset change range;

and if the voltage change value of each battery cell within the preset time is within the preset change range, determining that the battery cell balance of the automobile is required.

Preferably, the determining, by using the voltage of each of the battery cells, the battery cells to be equalized in all the battery cells, includes:

determining a cell corresponding to the lowest voltage, and judging whether a difference value between the lowest voltage and voltages corresponding to other cells is greater than the voltage threshold, where the other cells are cells other than the cell corresponding to the lowest voltage in all the cells;

and determining the electric core corresponding to the difference value larger than the voltage threshold value as the electric core to be balanced.

Preferably, after equalizing all the cells to be equalized, the method further includes:

and for each cell to be balanced, if the time for balancing the cell to be balanced reaches preset balancing time, stopping balancing the cell to be balanced.

if the difference value between the highest voltage and the lowest voltage is smaller than the voltage threshold, stopping balancing all the electric cores to be balanced;

or,

if the cell equalization temperature is not within the preset temperature range, stopping equalization of all the cells to be equalized;

or,

and for each cell to be balanced, if the cell to be balanced breaks down, stopping balancing all the cells to be balanced.

A second aspect of an embodiment of the present invention discloses a battery management system, including:

the acquisition unit is used for acquiring the battery cell equilibrium temperature of the automobile and the battery cell states of all battery cells, the automobile is in a starting state, and the battery cell states comprise: voltage and temperature of the cell;

a first determining unit, configured to determine whether the vehicle needs to perform cell balancing based on the cell balancing temperature and the cell state of each cell, and if the vehicle needs to perform cell balancing, execute the cell balancing

A second determination unit;

the second determining unit is configured to determine, by using the voltage of each of the battery cells, the battery cells to be balanced in all the battery cells that need to be balanced;

and the balancing unit is used for balancing all the electric cores to be balanced.

Preferably, the first determining unit is specifically configured to: judging whether the automobile accords with an electric core balancing condition, if so, determining that the automobile needs to be subjected to electric core balancing, wherein the electric core balancing condition comprises the following steps: the difference value of the highest voltage and the lowest voltage in the voltages of all the battery cells is larger than a voltage threshold value, each battery cell has no fault, the battery cell equilibrium temperature is within the preset temperature range, and when the current of each battery cell is a preset current value, the voltage change value of each battery cell within preset time is within a preset change range, wherein whether the battery cell has a fault or not is determined based on the state of the battery cell.

Preferably, the second determining unit is specifically configured to: determining a cell corresponding to the lowest voltage, judging whether a difference value between the lowest voltage and voltages corresponding to other cells is greater than the voltage threshold, and determining that the cell corresponding to the difference value greater than the voltage threshold is a cell to be balanced, and the other cells are cells except the cell corresponding to the lowest voltage in all the cells.

Preferably, the system further comprises:

and the stopping unit is used for stopping the balancing of the electric core to be balanced if the time for balancing the electric core to be balanced reaches the preset balancing time aiming at each electric core to be balanced.

Based on the above-mentioned cell balancing method and battery management system provided by the embodiments of the present invention, the method is: when the automobile is in a starting state, acquiring the cell equilibrium temperature of the automobile and the cell states of all the cells; determining whether the automobile needs to be subjected to cell balancing or not based on the cell balancing temperature and the cell state of each cell; if the automobile needs to perform cell balancing, determining the to-be-balanced cell in all the cells by using the voltage of each cell; and balancing all the electric cores to be balanced. In the scheme, whether the automobile needs to be subjected to battery cell equalization is determined according to the battery cell equalization temperature and the battery cell state when the automobile is in a starting state. If the automobile needs to be balanced in battery cells, the battery cells to be balanced are determined and balanced, the battery management system is prevented from being under-voltage due to repeated self-awakening after the automobile is flamed out, normal starting of the automobile is guaranteed, and automobile use experience is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a flowchart of a cell balancing method according to an embodiment of the present invention;

fig. 2 is a schematic flow chart illustrating a process of determining whether a cell balancing operation is required for an automobile according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a balancing logic of an automotive electrical core according to an embodiment of the present invention;

fig. 4 is a block diagram of a battery management system according to an embodiment of the present invention;

fig. 5 is a block diagram of another battery management system according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In this application, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

It can be known from the background art that the current balancing strategy for automobiles is that after the automobiles are flamed out, the BMS wakes up once by itself at intervals to check whether the battery cells need to be balanced, and discharges the battery cells needing to be balanced. But BMS is from awakening up and need consuming the electric quantity, and when the car stood for a long time not, BMS was awaken up and carried out the battery that the equilibrium can make the car under-voltage to electric core many times from awakening up to lead to the unable normal start of car, seriously influence the car and use experience.

Therefore, the embodiment of the invention provides a battery cell balancing method and a battery management system, and whether the battery cell balancing is needed by an automobile is determined according to the battery cell balancing temperature and the battery cell state when the automobile is in a starting state. If the automobile needs to be balanced in battery cells, the battery cells to be balanced are determined and balanced, and the battery cells to be balanced are prevented from being under-voltage caused by self-awakening of the battery management system for multiple times after the automobile is flamed out, so that normal starting of the automobile is guaranteed, and automobile use experience is improved.

It should be noted that, the automobiles to which the cell balancing method provided in the embodiment of the present invention is applied include, but are not limited to: pure fuel vehicles, hybrid electric vehicles and new energy vehicles. Namely, the cell balancing method is applicable to automobiles with battery packs.

Referring to fig. 1, a flowchart of a cell balancing method provided in an embodiment of the present invention is shown, where the cell balancing method includes the following steps:

step S101: and acquiring the cell equilibrium temperature of the automobile and the cell states of all the cells.

In the process of specifically implementing step S101, when the automobile is in a starting state, the cell equilibrium temperature of the automobile and the cell states of all the cells are acquired. The cell state includes: voltage and temperature of the cell. And judging whether the battery cell has faults according to the battery cell state, namely judging whether the battery cell has faults such as overvoltage, undervoltage and overtemperature.

It should be noted that the cell equilibrium temperature is a temperature near an equilibrium resistor on a Printed Circuit Board (PCB) of the vehicle, that is, the cell equilibrium temperature is acquired by a temperature sensor attached to the equilibrium resistor.

It is further noted that different types of automobiles correspond to different numbers of cells, for example, for an automobile with a 48V light mix system, the 48V light mix system has 13 cells. In the embodiment of the present invention, the number of battery cells of the automobile is not specifically limited.

Step S102: and determining whether the automobile needs to be subjected to cell equalization or not based on the cell equalization temperature and the cell state of each cell. And if the automobile needs to perform cell balancing, executing step S103.

In the process of specifically implementing the step S102, a plurality of cell balancing conditions are preset, whether the vehicle meets the cell balancing conditions is determined according to the cell balancing temperature and the cell state of each cell, and if yes, it is determined that the vehicle needs to perform cell balancing.

It should be noted that the aforementioned plurality of cell balancing conditions include, but are not limited to, the four cell balancing conditions shown in a1 to a4 described below.

A1, wherein the difference value of the highest voltage and the lowest voltage in the voltages of all the battery cells is larger than a voltage threshold value.

And A2, each battery cell has no fault, namely all the battery cells are in a fault-free state.

A3, the cell equilibrium temperature is in the preset temperature range.

And A4, when the current of each battery cell is a preset current value, the voltage change value of each battery cell in a preset time is in the preset change range. For example: when the current of each cell is at 2A, the voltage of each cell is unchanged within 5 seconds.

It should be noted that when the automobile simultaneously satisfies the cell balancing conditions shown in a1 to a4, it is determined that the automobile needs to perform cell balancing.

It should be further noted that the cell balancing conditions shown in a1 to a4 are only used for illustration, and specific cell balancing conditions are set by a technician according to actual situations, and are not specifically limited in the embodiment of the present invention.

Step S103: and determining the cells to be balanced in all the cells by using the voltage of each cell.

In the process of specifically implementing step S103, when it is determined that the vehicle needs to perform cell balancing, a cell to be balanced needs to be selected from all the cells. The specific selection mode is as follows:

and determining the battery cell corresponding to the lowest voltage, judging whether the difference value between the lowest voltage and the voltages corresponding to other battery cells is greater than the voltage threshold value, and determining the battery cell corresponding to the difference value greater than the voltage threshold value as the battery cell to be balanced. And the other battery cells are battery cells except the battery cell corresponding to the lowest voltage in all the battery cells.

For example: suppose the vehicle carries 13 cells, named as cell 1 to cell 13, respectively, and the voltage of cell 1 is the lowest. Calculating the difference between the battery cell 2 and the battery cell 1, calculating the difference between the battery cell 3 and the battery cell 1, and so on, and calculating the difference between the battery cell 4 and the battery cell 13 and the battery cell 1 respectively. And determining the battery cell corresponding to the difference value larger than 20mV as the battery cell to be balanced.

In the process of further implementing step S103, after the battery cell to be balanced is determined, a balancing flag corresponding to the battery cell to be balanced is turned on, where the balancing flag is used to indicate that the battery cell needs to be balanced. And respectively calculating the balance time corresponding to each electric core to be balanced, namely each electric core to be balanced has the balance time corresponding to the electric core to be balanced. For example: an equalization time of 777s corresponds to an equalization of 1 mV.

Step S104: and balancing all the electric cores to be balanced.

In the process of specifically implementing step S104, all the battery cells to be equalized are equalized, so that voltages of all the battery cells tend to be consistent. The equalizing method for all the cells to be equalized includes, but is not limited to: and balancing the electric cores to be balanced one by one, or balancing all the electric cores to be balanced simultaneously.

Preferably, for each electric core to be balanced, if the time for balancing the electric core to be balanced reaches a preset balancing time, the balancing of the electric core to be balanced is stopped.

It should be noted that, in the process of equalizing all the cells to be equalized, a plurality of equalization stopping conditions are preset, and when the vehicle meets any one or more of the equalization stopping conditions, the equalization of all the cells to be equalized is stopped, where the equalization stopping conditions include, but are not limited to, the equalization stopping conditions shown in B1 to B3 below.

And B1, if the difference value of the highest voltage and the lowest voltage is smaller than the voltage threshold, stopping balancing all the battery cells to be balanced.

And B2, if the cell equilibrium temperature is not within the preset temperature range, stopping the equilibrium of all the cells to be equilibrated.

And B3, for each battery cell to be balanced, if the battery cell to be balanced fails, stopping balancing all the battery cells to be balanced.

When the automobile meets one or more of the conditions for stopping equalization in examples B1 to B3, the equalization of all the cells to be equalized is stopped.

It should be further noted that the stop equalization conditions shown in the above examples B1 to B3 are only for illustration, and the specific stop equalization conditions are set by the skilled person according to the actual situation, and are not specifically limited in the embodiments of the present invention.

In the embodiment of the invention, whether the automobile needs to be subjected to cell balancing is determined according to the cell balancing temperature and the cell state when the automobile is in a starting state. If the automobile needs to be balanced in battery cells, the battery cells to be balanced are determined and balanced, the battery management system is prevented from being under-voltage due to repeated self-awakening after the automobile is flamed out, normal starting of the automobile is guaranteed, and automobile use experience is improved.

In the embodiment of the present invention, referring to fig. 2, a schematic flow chart of determining whether the vehicle needs to perform cell balancing according to the process of determining whether the vehicle conforms to the cell balancing in step S102 in step S1 is shown. It should be noted that fig. 2 shows only one example of determining whether the cell balancing of the automobile is required, where the fig. 2 includes the following steps:

step S201: and acquiring the highest voltage and the lowest voltage in the voltages of all the battery cells.

In the process of specifically implementing step S201, the voltages of all the battery cells are obtained in advance, and the highest voltage and the lowest voltage in the voltages of all the battery cells are obtained.

Step S202: and judging whether the difference value of the highest voltage and the lowest voltage is greater than a voltage threshold value. If the difference is greater than the voltage threshold, step S203 is executed.

Step S203: and judging whether each battery cell has a fault or not based on the battery cell state of each battery cell. If each of the battery cells has no fault, step S204 is executed.

Step S204: and judging whether the cell equilibrium temperature corresponding to the automobile is within a preset temperature range. And if the cell equilibrium temperature is within the preset temperature range, executing step S205.

Step S205: and when the current of each electric core is a preset current value, judging whether the voltage change value of each electric core within preset time is within a preset change range. And if the voltage change value of each battery cell within the preset time is within the preset change range, executing step S206.

Step S206: and determining that the automobile needs to be subjected to cell balancing.

It should be noted that, the execution principle of step S201 to step S206 may refer to the content shown in the corresponding step in fig. 1 in the embodiment of the present invention, and is not described herein again.

It should be further noted that the execution sequence of the above steps S201 to S206 is only for illustration. In practical applications, when the automobile simultaneously satisfies the plurality of cell balancing conditions in step S102 in the embodiment of the present invention described above, it is determined that the automobile needs to perform cell balancing.

In the embodiment of the invention, a plurality of battery cell balancing conditions are preset, and when the automobile simultaneously meets the plurality of battery cell balancing conditions in a starting state, the fact that the automobile needs to be subjected to battery cell balancing is determined. The method comprises the steps of determining the to-be-balanced battery cells to be balanced, balancing the to-be-balanced battery cells, avoiding battery under-voltage caused by self-awakening of a battery management system for many times after the automobile is flamed out, ensuring normal starting of the automobile and improving automobile use experience.

To better explain the contents shown in fig. 1 and fig. 2 in the above embodiments of the present invention, an example is illustrated by a schematic diagram of an automobile cell balancing logic shown in fig. 3.

In said fig. 3, comprising: the device comprises a balance judging module, a balance number selecting and time pre-estimating module and a balance executing module.

When the automobile is in a starting state, the balance judgment module judges whether the automobile meets preset 4-cell balance conditions, and if so, the balance number selection and time estimation module is started.

The equalization number selection and time estimation module determines to-be-equalized battery cells needing equalization in all the battery cells, calculates the equalization time of each to-be-equalized battery cell, and starts the equalization execution module.

And the balance execution module balances all the electric cores to be balanced, judges whether the automobile meets 4 preset balance stopping conditions, and stops the balance process of the electric cores to be balanced if the automobile meets the preset balance stopping conditions.

It should be noted that, for the execution principle of each module shown in fig. 3, reference may be made to the contents shown in fig. 1 and fig. 2, and details are not repeated here.

Corresponding to the above method for cell balancing provided in the embodiment of the present invention, referring to fig. 4, an embodiment of the present invention further provides a structural block diagram of a battery management system, where the battery management system includes: an acquisition unit 401, a first determination unit 402, a second determination unit 403, and an equalization unit 404;

an obtaining unit 401, configured to obtain a cell equilibrium temperature of the vehicle and cell states of all cells, where the vehicle is in a starting state, and the cell states include: voltage and temperature of the cell.

A first determining unit 402, configured to determine whether the vehicle needs to perform cell balancing based on the cell balancing temperature and the cell state of each cell, and if the vehicle needs to perform cell balancing, execute a second determining unit 403.

In a specific implementation, the first determining unit 402 is specifically configured to: judging whether the automobile accords with an electric core balancing condition, if so, determining that the automobile needs to be subjected to electric core balancing, wherein the electric core balancing condition comprises the following steps: the difference value of the highest voltage and the lowest voltage in the voltages of all the battery cells is larger than a voltage threshold value, each battery cell has no fault, the battery cell equilibrium temperature is within the preset temperature range, and when the current of each battery cell is a preset current value, the voltage change value of each battery cell within preset time is within a preset change range, wherein whether the battery cell has a fault or not is determined based on the state of the battery cell.

The second determining unit 403 is configured to determine, by using the voltage of each of the battery cells, a battery cell to be balanced in all the battery cells.

In a specific implementation, the second determining unit 403 is specifically configured to: determining a cell corresponding to the lowest voltage, judging whether a difference value between the lowest voltage and voltages corresponding to other cells is greater than the voltage threshold, and determining that the cell corresponding to the difference value greater than the voltage threshold is a cell to be balanced, and the other cells are cells except the cell corresponding to the lowest voltage in all the cells.

And the equalizing unit 404 is configured to equalize all the electric cores to be equalized.

Preferably, in combination with what is shown in fig. 4, the first determining unit 402 includes: the device comprises an acquisition module, a first judgment module, a second judgment module, a third judgment module, a fourth judgment module and a determination module.

The execution principle of each module is as follows:

and the acquisition module is used for acquiring the highest voltage and the lowest voltage in the voltages of all the battery cells.

And the first judgment module is used for judging whether the difference value of the highest voltage and the lowest voltage is greater than a voltage threshold value. And if the difference value is greater than the threshold value, executing a second judgment module.

The second judging module judges whether each battery cell has a fault or not based on the battery cell state of each battery cell. And if each battery cell does not have a fault, executing a third judgment module.

And the third judgment module is used for judging whether the cell equilibrium temperature corresponding to the automobile is within a preset temperature range. And if the cell equilibrium temperature is within the preset temperature range, executing a fourth judgment module.

And the fourth judging module is used for judging whether the voltage change value of each electric core in preset time is within a preset change range when the current of each electric core is a preset current value. And if the voltage change value of each battery cell in the preset time is within the preset change range, executing a determining module.

The determining module is used for determining that the electric core balance of the automobile needs to be carried out.

Preferably, referring to fig. 5 in conjunction with fig. 4, a structural block diagram of a battery management system according to an embodiment of the present invention is shown, where the battery management system further includes:

a stopping unit 405, configured to, for each to-be-equalized battery cell, stop equalization on the to-be-equalized battery cell if the time for equalizing the to-be-equalized battery cell reaches a preset equalization time.

Preferably, the stopping unit 405 is further configured to: and if the difference value of the highest voltage and the lowest voltage is smaller than the voltage threshold, stopping balancing all the electric cores to be balanced. Or if the cell equalization temperature is not within the preset temperature range, stopping equalization of all the cells to be equalized. Or, for each cell to be balanced, if the cell to be balanced fails, stopping balancing all the cells to be balanced.

In the embodiment of the invention, by presetting a plurality of balance stopping conditions, when the automobile meets any balance stopping condition, the balance of the battery cell to be balanced is stopped, the running safety of the automobile is ensured, and the safety of the automobile is improved.

In summary, an embodiment of the present invention provides a battery cell balancing method and a battery management system, where the method includes: when the automobile is in a starting state, acquiring the cell equilibrium temperature of the automobile and the cell states of all the cells; determining whether the automobile needs to be subjected to cell balancing or not based on the cell balancing temperature and the cell state of each cell; if the automobile needs to perform cell balancing, determining the to-be-balanced cell in all the cells by using the voltage of each cell; and balancing all the electric cores to be balanced. In the scheme, whether the automobile needs to be subjected to battery cell equalization is determined according to the battery cell equalization temperature and the battery cell state when the automobile is in a starting state. If the automobile needs to be balanced in battery cells, the battery cells to be balanced are determined and balanced, the battery management system is prevented from being under-voltage due to repeated self-awakening after the automobile is flamed out, normal starting of the automobile is guaranteed, and automobile use experience is improved.

The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, the system or system embodiments are substantially similar to the method embodiments and therefore are described in a relatively simple manner, and reference may be made to some of the descriptions of the method embodiments for related points. The above-described system and system embodiments are only illustrative, wherein the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment. One of ordinary skill in the art can understand and implement it without inventive effort.

Those of skill would further appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A cell balancing method, comprising:

and balancing all the electric cores to be balanced.

2. The method of claim 1, wherein the determining whether the vehicle requires cell balancing based on the cell balancing temperature and the cell state of each of the cells comprises:

3. The method of claim 1, wherein the determining whether the vehicle requires cell balancing based on the cell state and the voltage of each of the cells comprises:

4. The method of claim 2, wherein the determining, by using the voltage of each of the cells, the cells to be equalized among all the cells, which need to be equalized, comprises:

5. The method of claim 1, wherein after the equalizing all the cells to be equalized, the method further comprises:

6. The method according to any one of claims 1 to 4, wherein after the equalizing all the cells to be equalized, the method further comprises:

or,

7. A battery management system, the system comprising:

the first determining unit is used for determining whether the automobile needs to be subjected to cell equalization or not based on the cell equalization temperature and the cell state of each cell, and executing a second determining unit if the automobile needs to be subjected to cell equalization;

8. The system according to claim 7, wherein the first determining unit is specifically configured to: judging whether the automobile accords with an electric core balancing condition, if so, determining that the automobile needs to be subjected to electric core balancing, wherein the electric core balancing condition comprises the following steps: the difference value of the highest voltage and the lowest voltage in the voltages of all the battery cells is larger than a voltage threshold value, each battery cell has no fault, the battery cell equilibrium temperature is within the preset temperature range, and when the current of each battery cell is a preset current value, the voltage change value of each battery cell within preset time is within a preset change range, wherein whether the battery cell has a fault or not is determined based on the state of the battery cell.

9. The system according to claim 7, wherein the second determining unit is specifically configured to: determining a cell corresponding to the lowest voltage, judging whether a difference value between the lowest voltage and voltages corresponding to other cells is greater than the voltage threshold, and determining that the cell corresponding to the difference value greater than the voltage threshold is a cell to be balanced, and the other cells are cells except the cell corresponding to the lowest voltage in all the cells.

10. The system of claim 7, further comprising: