CN114675193B

CN114675193B - Allowable power estimation method, battery management system and storage medium

Info

Publication number: CN114675193B
Application number: CN202011572286.2A
Authority: CN
Inventors: 雷有玲; 黄光美; 徐广玉
Original assignee: Contemporary Amperex Technology Co Ltd
Current assignee: Contemporary Amperex Technology Co Ltd
Filing date: 2020-12-25
Publication date: 2024-07-12
Anticipated expiration: 2040-12-25

Abstract

The application provides an allowable power estimation method, a battery management system and a storage medium. The method comprises the following steps: acquiring a first state of charge and a first temperature value of a first type of battery cell; acquiring a second state of charge of a second type of battery cell and a second temperature value; determining a first allowable discharge current based on the first state of charge and the first temperature value; determining a second allowable discharge current based on the second state of charge and a second temperature value; the allowable discharge power of the battery pack is calculated based on the discharge current having the smallest value among the first allowable discharge current and the second allowable discharge current, the cutoff voltage of the first type of battery cell, the number of battery cells of the first type of battery cell, the cutoff voltage of the second type of battery cell, and the number of battery cells of the second type of battery cell. By this means, when the two types of cells are used in series, the maximum allowable discharge power of the battery pack can be output on the premise of protecting the safety of the cells, and the maximum discharge capacity of the cells can be further exerted.

Description

Allowable power estimation method, battery management system and storage medium

Technical Field

The present application relates to the field of battery technologies, and in particular, to a permissible power estimation method, a battery management system, and a storage medium.

Background

Currently, electric vehicles are taken as one of effective ways of energy conservation and emission reduction, and various enterprises invest a large amount of resources to develop the electric vehicles.

The power battery system is used as an energy storage unit Of an electric automobile, and in the process Of charging and discharging, the residual electric quantity Of the power battery system needs to be monitored in real time, and the ratio Of the residual electric quantity to the battery capacity Of 100% full Charge is State Of Charge (SOC for short). In actual use, the SOC is mainly used as reference information for protecting the battery, determination of power estimation, etc. In the prior art, power estimation is mostly realized by combining the voltages of the battery cells on the basis of the SOC, and the power estimation method can only be used for estimating the power of a single type of battery pack, and when the battery pack consists of different types of battery cells in series, the allowable power of the whole battery pack cannot be effectively determined by adopting the method.

Disclosure of Invention

The embodiment of the application provides an allowable power estimation method, a battery management system and a storage medium, which are used for improving the estimation accuracy of allowable power of a battery pack comprising different types of battery cells connected in series.

The invention is realized in the following way:

in a first aspect, an embodiment of the present application provides a permissible discharge power estimation method, including: acquiring a first state of charge and a first temperature value of a first type of battery cells in a battery pack; acquiring a second state of charge and a second temperature value of a second type of battery cell in the battery pack; determining a first allowable discharge current for the first class of cells based on the first state of charge and the first temperature value; determining a second allowable discharge current for the second class of cells based on the second state of charge and the second temperature value; and calculating allowable discharge power of the battery pack based on the discharge current with the smallest value among the first allowable discharge current and the second allowable discharge current, the cut-off voltage of the first type of battery cells, the number of battery cells of the first type of battery cells, the cut-off voltage of the second type of battery cells and the number of battery cells of the second type of battery cells.

In the embodiment of the application, the first allowable discharge current of the first type of battery cells is determined through the current first charge state and the first temperature value of the first type of battery cells, the second allowable discharge current of the second type of battery cells is determined through the current second charge state and the second temperature value of the second type of battery cells, then the current with the smallest value in the two allowable discharge currents is used as the allowable discharge current of the battery pack, and finally the allowable discharge power of the whole battery pack is calculated by combining the cut-off voltage and the number of the battery cells of the two types.

In a second aspect, an embodiment of the present application provides a method for estimating allowable charging power, including: acquiring a first state of charge and a first temperature value of a first type of battery cells in a battery pack; acquiring a second state of charge and a second temperature value of a second type of battery cell in the battery pack; determining a first allowable charge current for the first class of cells based on the first state of charge and the first temperature value; determining a second allowable charge current for the second class of cells based on the second state of charge and the second temperature value; and calculating the allowable charging power of the battery pack based on the charging current with the smallest value of the first allowable charging current and the second allowable charging current, the open circuit voltage of the first type of battery cells, the number of battery cells of the first type of battery cells, the open circuit voltage of the second type of battery cells and the number of battery cells of the second type of battery cells.

In the embodiment of the application, the first allowable charging current of the first type of battery cells is determined through the current first state of charge and the first temperature value of the first type of battery cells, the second allowable charging current of the second type of battery cells is determined through the current second state of charge and the second temperature value of the second type of battery cells, then the current with the smallest value in the two allowable charging currents is used as the allowable charging current of the battery pack, and finally the allowable charging power of the whole battery pack is calculated by combining the open circuit voltage and the number of the battery cells of the two types.

In a third aspect, an embodiment of the present application provides a battery cell control device, including: the first acquisition module is used for acquiring a first state of charge and a first temperature value of a first type of battery cells in the battery pack and acquiring a second state of charge and a second temperature value of a second type of battery cells in the battery pack; a first determination module configured to determine a first allowable discharge current of the first class of cells based on the first state of charge and the first temperature value; and determining a second allowable discharge current for the second type of cell based on the second state of charge and the second temperature value; and the calculating module is used for calculating the allowable discharge power of the battery pack based on the discharge current with the smallest value in the first allowable discharge current and the second allowable discharge current, the cut-off voltage of the first type of battery cells, the number of the battery cells of the first type of battery cells, the cut-off voltage of the second type of battery cells and the number of the battery cells of the second type of battery cells.

In a fourth aspect, an embodiment of the present application further provides a device for controlling a battery cell, including: the acquisition module is used for acquiring a first state of charge and a first temperature value of a first type of battery cells in the battery pack; obtaining a second state of charge and a second temperature value of a second type of battery cells in the battery pack; a first determining module configured to determine a first allowable charging current for the first class of cells based on the first state of charge and the first temperature value; and determining a second allowable charge current for the second type of cell based on the second state of charge and the second temperature value; and the calculating module is used for calculating the allowable charging power of the battery pack based on the charging current with the smallest value in the first allowable charging current and the second allowable charging current, the open-circuit voltage of the first type of battery cells, the number of battery cells of the first type of battery cells, the open-circuit voltage of the second type of battery cells and the number of battery cells of the second type of battery cells.

In a fifth aspect, an embodiment of the present application provides a battery management system, including: the device comprises a processor and a memory, wherein the processor is connected with the memory; the memory is used for storing programs; the processor is configured to invoke a program stored in the memory to perform a method as provided by the embodiments of the first aspect described above and/or in combination with some possible implementations of the embodiments of the first aspect described above.

In a sixth aspect, an embodiment of the present application provides a battery management system, including: the device comprises a processor and a memory, wherein the processor is connected with the memory; the memory is used for storing programs; the processor is configured to invoke a program stored in the memory to perform a method as provided by the embodiments of the second aspect described above and/or in connection with some possible implementations of the embodiments of the second aspect described above.

In a seventh aspect, embodiments of the present application provide a storage medium having stored thereon a computer program which, when executed by a processor, performs a method as provided by the embodiments of the first aspect described above and/or in connection with some possible implementations of the embodiments of the first aspect described above.

In an eighth aspect, embodiments of the present application provide a storage medium having stored thereon a computer program which, when executed by a processor, performs a method as provided by the above-described second aspect embodiments and/or in connection with some possible implementations of the above-described second aspect embodiments.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments of the present application will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present application and should not be considered as limiting the scope, and other related drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a battery management system according to an embodiment of the present application.

Fig. 2 is a flowchart illustrating a method for estimating allowable discharge power according to an embodiment of the present application.

Fig. 3 is a schematic connection diagram of a battery management system and a battery pack according to an embodiment of the present application.

Fig. 4 is a flowchart illustrating a method for estimating allowable charging power according to an embodiment of the present application.

Fig. 5 is a block diagram of a battery cell control device according to an embodiment of the present application.

Fig. 6 is a block diagram of another battery cell control device according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application.

In view of the current power estimation, for battery packs comprising different kinds of cells connected in series, the allowable power of the whole battery pack cannot be determined effectively (wherein the allowable power of the battery pack comprises allowable discharge power and allowable charge power). The present inventors have studied and studied to solve the above problems by proposing the following examples.

First, referring to fig. 1, a schematic structure diagram of a battery management system 100 using an allowable discharge power estimation method is provided. The battery management system 100 may be mounted on an electric vehicle, an unmanned aerial vehicle, or the like. Structurally, the battery management system 100 may include a processor 110 and a memory 120.

The processor 110 is electrically connected to the memory 120, either directly or indirectly, to enable data transmission or interaction, for example, the elements may be electrically connected to each other via one or more communication buses or signal lines. The above-described method includes at least one software module that may be stored in the memory 120 in the form of software or Firmware (Firmware) or cured in the battery management system 100. The processor 110 is configured to execute executable modules stored in the memory 120. The processor 110 may execute the computer program after receiving the execution instructions.

The processor 110 may be an integrated circuit chip with signal processing capability. The Processor 110 may also be a general purpose Processor, for example, a digital signal Processor (DIGITAL SIGNAL Processor, DSP), application SPECIFIC INTEGRATED Circuit (ASIC), discrete gate or transistor logic, discrete hardware components, and may implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present application. Further, the general purpose processor may be a microprocessor or any conventional processor or the like.

The Memory 120 may be, but is not limited to, random access Memory (Random Access Memory, RAM), read Only Memory (ROM), programmable Read Only Memory (Programmable Read-Only Memory, PROM), erasable programmable Read Only Memory (Erasable Programmable Read-Only Memory, EPROM), and electrically erasable programmable Read Only Memory (Electric Erasable Programmable Read-Only Memory, EEPROM). The memory 120 is used for storing a program, and the processor 110 executes the program after receiving an execution instruction.

It should be noted that the structure shown in fig. 1 is only illustrative, and the battery management system 100 according to the embodiment of the application may further have fewer or more components than those shown in fig. 1, or may have a different configuration from that shown in fig. 1. In addition, the components shown in fig. 1 may be implemented by software, hardware, or a combination thereof.

Referring to fig. 2, fig. 2 is a flow chart of a permissible discharge power estimation method according to an embodiment of the present application, and it should be noted that the permissible discharge power estimation method according to the embodiment of the present application is not limited by the sequence shown in fig. 2 and the following. The method comprises the following steps: step S101 to step S105.

Step S101: and acquiring a first state of charge and a first temperature value of a first type of battery cell in the battery pack.

Step S102: and obtaining a second state of charge and a second temperature value of a second type of battery cell in the battery pack.

Step S103: a first allowable discharge current for the first class of cells is determined based on the first state of charge and the first temperature value.

Step S104: a second allowable discharge current for the second type of cell is determined based on the second state of charge and the second temperature value.

Step S105: the allowable discharge power of the battery pack is calculated based on the discharge current having the smallest value among the first allowable discharge current and the second allowable discharge current, the cutoff voltage of the first type of battery cell, the number of battery cells of the first type of battery cell, the cutoff voltage of the second type of battery cell, and the number of battery cells of the second type of battery cell.

In summary, in the embodiment of the present application, the current first state of charge and the first temperature value of the first type of battery cell are used to determine the first allowable discharge current of the first type of battery cell, the current second state of charge and the second temperature value of the second type of battery cell are used to determine the second allowable discharge current of the second type of battery cell, then the current with the smallest value of the two allowable discharge currents is used as the allowable discharge current of the battery pack, and finally the allowable discharge power of the whole battery pack is calculated by combining the cut-off voltage and the number of the two types of battery cells.

The following describes the complete process of the allowable discharge power estimation method described above in connection with specific examples.

In step S101 and step S102, the battery management system is electrically connected to the battery pack. Specifically, referring to fig. 3, the battery management system is electrically connected to the first type of battery cell and the second type of battery cell, respectively. The battery management system acquires a first state of charge and a first temperature value of a first type of battery cell in real time, and acquires a second state of charge and a second temperature value of a second type of battery cell in the battery pack in real time.

The surface temperature of the battery cell can be used as the temperature of the battery cell, that is, a temperature sensor for acquiring a temperature value can be arranged on the surface of the battery cell.

The battery management system obtains a first state of charge of the first type of battery cell in real time, wherein the first state of charge is 80%, and the first temperature value is 3 ℃; the battery management system acquires a second charge state of a second type of battery cell in real time to be 60%, and the first temperature value is 5 ℃.

The above-mentioned battery cell types may include, but are not limited to, a lithium cobalt oxide battery cell, a nickel cobalt manganese battery cell, and a lithium iron phosphate battery cell, for example, the first battery cell type may be a lithium cobalt oxide battery cell, the second battery cell type may be a nickel cobalt manganese battery cell, and for example, the first battery cell type may be a lithium iron phosphate battery cell, and the second battery cell type may be a lithium cobalt oxide battery cell.

In step S103 and step S104, the allowable discharge current of the battery cell determined based on the state of charge and the temperature value may be obtained by means of a look-up table. For example, a discharge experiment is performed on the battery cell in advance to form a current two-dimensional meter. The current two-dimensional table comprises the types of the battery cells, the charge states of the current battery cells, the battery cell temperature and allowable discharge current. In the embodiment of the application, the first type of battery cells can be subjected to a discharge experiment in advance to obtain the current two-dimensional table of the first type of battery cells, and the second type of battery cells can be subjected to a discharge experiment to obtain the current two-dimensional table of the second type of battery cells. Then, the two-dimensional current table of the first type of battery cells and the two-dimensional current table of the second type of battery cells are stored in a battery management system, and after the battery management system obtains the first charge state and the first temperature value of the first type of battery cells, the first allowable discharge current can be directly found out from the two-dimensional current table of the first type of battery cells; after the battery management system obtains the second charge state and the second temperature value of the second type of battery cell, the second allowable discharge current can be directly found out from the current two-dimensional table of the second type of battery cell.

Of course, the battery management system may directly store the corresponding relationship among the charge state, the cell temperature and the allowable discharge current, which is not limited by the present application.

In order to ensure that the determined allowable discharge current is added to meet the service condition of the battery cell, the accuracy of the allowable discharge power of the determined battery pack is improved. That is, step S103 specifically includes: determining a first initial allowable discharge current for the first class of cells based on the first state of charge and the first temperature value; the first allowable discharge current is calculated based on the first initial allowable discharge current and the aging coefficient of the first-class cell. The step S104 specifically includes: determining a second initial allowable discharge current for the second type of cell based on the second state of charge and the second temperature value; the second allowable discharge current is calculated based on the second initial allowable discharge current and the aging coefficient of the second type of cell.

It is understood that the first initial allowable discharge current may be a table look-up current value obtained by a two-dimensional current table of the first type of battery cell, and the aging coefficient of the first type of battery cell is related to the current time of use of the first type of battery cell. It should be noted that, the battery core can be subjected to aging test when leaving the factory, so as to obtain the aging coefficients corresponding to the battery core under different use time lengths. For example, the values of the aging coefficients may be 0.8, 0.9. And finally, multiplying the first initial allowable discharge current by the corresponding aging coefficient to obtain the first allowable discharge current. Accordingly, the second initial allowable discharge current may be a table look-up current value obtained by a two-dimensional current meter of the second type of battery cell, and the aging coefficient of the second type of battery cell is related to the current use time of the second type of battery cell. For example, the values of the aging coefficients may be 0.6, 0.9. And finally, multiplying the second initial allowable discharge current by the corresponding aging coefficient to obtain the second allowable discharge current.

After the first allowable discharge current of the first type of cell and the second allowable discharge current of the second type of cell are obtained, the allowable discharge power included in the battery can be calculated in step S105. When calculating the allowable discharge power of the battery pack, the allowable discharge current of the battery pack is the discharge current having the smallest value among the first allowable discharge current and the second allowable discharge current. The specific formula for calculating the allowable discharge power of the battery pack is as follows:

Allowable discharge power of the battery pack=allowable discharge current of the battery pack (cut-off voltage of the first type of cell×number of cells of the first type of cell+cut-off voltage of the second type of cell×number of cells of the second type of cell);

Where allowable discharge current of the battery pack=min (first allowable discharge current, second allowable discharge current).

Min in the above formula is taken to be small, and the cut-off voltage in the above formula is preset according to the type of the battery cell, and the cut-off voltages of different types of battery cells are different.

It should be noted that the above description is only about two types of battery cells, and the allowable discharge power estimation method provided by the embodiment of the application is also applicable to three types of battery cells and four types of battery cells.

It should be noted that, in the use process of the battery pack, the power will change along with the use of the battery pack, so that in order to make the power fluctuation of each update smaller, the stability of the device using the battery pack during operation is improved.

Specifically, the adjustment process includes: acquiring a first voltage value of a first type of battery cell; acquiring a second voltage value of a second type of battery cell; and determining the regulated discharge power of the battery pack based on the voltage value, and updating the allowable discharge power of the battery pack to the discharge power with the minimum value in the regulated discharge power.

That is, in the above process, after the battery management system acquires the first voltage value of the first type of battery cell in real time, the first adjusted discharge power of the battery pack is determined based on the first voltage value. And after the battery management system acquires the second voltage of the second type of battery cells in real time, determining the second adjusted discharge power of the battery pack based on the second voltage value. Correspondingly, the allowable discharge power of the battery pack is updated to the discharge power with the smallest value in the first adjustment discharge power and the second adjustment discharge power.

Optionally, determining the adjusted discharge power of the battery pack based on the voltage value includes: judging whether the voltage value is smaller than a preset adjustment threshold value or not; when the voltage value is not smaller than a preset adjustment threshold value, taking the allowable discharge power of the battery pack as adjustment discharge power; when the voltage value is smaller than a preset adjustment threshold value, determining the reduction proportion of the allowable discharge power of the battery pack; wherein, the allowable discharge power of the battery pack is reduced in proportion to the voltage value which is the same as that of the preset adjustment threshold; the adjustment of the discharge power is determined based on the reduction ratio and the allowable discharge power of the battery pack.

The preset adjustment threshold may be determined according to different types of battery cells, for example, when the type of the battery cell is a lithium battery cell, the preset adjustment threshold may be 3.2V; when the battery cell is another kind of battery cell, the preset adjustment threshold value can be 3.6V, 4V, etc., which is not limited by the present application.

It should be noted that, when the voltage value is not less than the preset adjustment threshold, the state of the battery cell is good (e.g. the state of charge is good), and the allowable discharge power of the battery pack is used as the adjustment discharge power at this time, so that the battery pack can continue to output the maximum power, and the maximum discharge capability of the battery cell is further exerted.

When the voltage value is smaller than the preset adjustment threshold, the current allowable discharge power needs to be reduced, in the embodiment of the application, when the current allowable discharge power is reduced, the reduction proportion of the allowable discharge power of the battery pack is determined based on the reduction proportion of the voltage value compared with the preset adjustment threshold, and then the adjustment discharge power is determined by the reduction proportion and the allowable discharge power of the battery pack. For example, when the battery pack is applied to an electric vehicle, the stability of the electric vehicle can be improved through the dynamic adjustment process.

For example, assume that the preset adjustment threshold is 3V and the current voltage value is 2.8V; the allowable discharge power of the battery pack is 30W; the voltage value may be decreased by (2.8-3)/3=1/15 compared to the preset adjustment threshold. Since the allowable discharge power of the battery pack is reduced by the same ratio as the voltage value is reduced by the preset adjustment threshold, the allowable discharge power of the battery pack is reduced by 1/15. And then determining the adjusted discharge power according to the reduction ratio and the allowable discharge power of the battery pack, and finally adjusting the discharge power to be 30 (1-1/15) =28W.

In other embodiments, the allowable discharge power of the battery pack may be reduced by a ratio equal to the voltage value multiplied by the preset value. The preset value may be one half or one third, which is not limited in the present application.

Optionally, when the voltage value is smaller than the preset adjustment threshold, determining the adjusted discharge power of the battery pack based on the voltage value may further be: when the voltage value is smaller than a preset adjustment threshold value and the voltage value is larger than the cut-off voltage of the battery cell corresponding to the voltage value, determining the reduction ratio of the allowable discharge power of the battery pack; wherein, the allowable discharge power of the battery pack is reduced in proportion to the voltage value which is the same as that of the preset adjustment threshold; or when the voltage value is smaller than a preset adjustment threshold value and the voltage value is smaller than the cut-off voltage of the battery cell corresponding to the voltage value, determining the reduction ratio of the allowable discharge power of the battery pack; the allowable discharge power of the battery pack is reduced in proportion to the cut-off voltage of the battery core corresponding to the voltage value, which is the same as that of the battery core corresponding to the voltage value compared with a preset adjustment threshold value; the adjustment of the discharge power is determined based on the reduction ratio and the allowable discharge power of the battery pack.

It should be noted that, the above scheme is equivalent to setting an adjustment voltage based on the preset adjustment threshold, where the adjustment voltage is the cut-off voltage corresponding to the battery cell. That is, when the obtained voltage value is greater than the cutoff voltage and less than the preset adjustment threshold, the reduction ratio of the allowable discharge power of the battery pack is determined in accordance with the method in the foregoing embodiment, and the adjustment discharge power is determined based on the allowable discharge power of the battery pack in the reduction ratio. And when the voltage value is smaller than the cut-off voltage of the battery cell, determining the reduction ratio of the cut-off voltage compared with a preset adjustment threshold value as the reduction ratio of the allowable discharge power of the battery pack, and determining to adjust the discharge power according to the allowable discharge power of the battery pack in the reduction ratio.

For example, assuming that the preset adjustment threshold is 3V, the cut-off voltage corresponding to the battery cell is 2.8V; the allowable discharge power of the battery pack is 30W; and the current voltage value is 2.6V, and since the current voltage value is smaller than the cut-off voltage, the voltage value may have a decreasing ratio of (2.8-3)/3=1/15 compared to the preset adjustment threshold. Since the allowable discharge power of the battery pack is reduced by the same ratio as the cut-off voltage is reduced by the preset adjustment threshold, the allowable discharge power of the battery pack is reduced by 1/15. And then determining the adjusted discharge power according to the reduction ratio and the allowable discharge power of the battery pack, and finally adjusting the discharge power to be 30 (1-1/15) =28W.

In summary, when the voltage value of the battery cell is smaller than the preset adjustment threshold value and is larger than the cut-off voltage of the battery cell, the reduction ratio of the allowable discharge power of the battery pack is determined based on the reduction ratio of the voltage value compared with the preset adjustment threshold value, and then the adjustment discharge power is determined through the reduction ratio and the allowable discharge power of the battery pack. When the voltage value of the battery cell is smaller than the cut-off voltage of the battery cell, the reduction ratio of the allowable discharge power of the battery pack is determined based on the reduction ratio of the cut-off voltage compared with the preset adjustment threshold, and then the adjustment discharge power is determined through the reduction ratio and the allowable discharge power of the battery pack.

The following describes the estimation of allowable charge power, and based on the same inventive concept, the embodiment of the application also provides a battery management system applying the allowable charge power estimation method. The specific structure of the system is the same as that shown in fig. 1, and therefore, the description of the structure of the battery management system to which the allowable charge power estimation method is applied may refer to the foregoing embodiment, and the present application is not limited thereto.

Referring to fig. 4, the allowable charge power estimation method includes: step S201 to step S205.

Step S201: and acquiring a first state of charge and a first temperature value of a first type of battery cell in the battery pack.

Step S202: and obtaining a second state of charge and a second temperature value of a second type of battery cell in the battery pack.

Step S203: a first allowable charge current for the first class of cells is determined based on the first state of charge and the first temperature value.

Step S204: a second allowable charge current for the second type of cell is determined based on the second state of charge and the second temperature value.

Step S205: the allowable charge power of the battery pack is calculated based on the minimum value of the first allowable charge current and the second allowable charge current, the open circuit voltage of the first type of battery cell, the number of battery cells of the first type of battery cell, the open circuit voltage of the second type of battery cell, and the number of battery cells of the second type of battery cell.

The following describes the complete process of the allowable charge power estimation method described above in connection with specific examples.

The steps S201 to S202 are similar to the steps S101 and S102 in the allowable discharge power estimation method in the foregoing embodiment, and in order to avoid redundancy, the same parts are referred to each other.

In step S203 and step S204, the allowable charging current of the battery cell determined based on the state of charge and the temperature value may be obtained by means of a look-up table. For example, a charging experiment is performed on the battery cell in advance to form a current two-dimensional meter. The current two-dimensional table comprises the types of the battery cells, the charge states of the current battery cells, the battery cell temperature and the allowable charging current.

In the embodiment of the application, the charging experiment can be performed on the first type of battery cell in advance to obtain the current two-dimensional table of the first type of battery cell, and the charging experiment can be performed on the second type of battery cell to obtain the current two-dimensional table of the second type of battery cell. Then, the two-dimensional current table of the first type of battery core and the two-dimensional current table of the second type of battery core are stored in a battery management system, and after the battery management system obtains the first charge state and the first temperature value of the first type of battery core, the first allowable charging current can be directly found out from the two-dimensional current table of the first type of battery core; after the battery management system obtains the second state of charge and the second temperature value of the second type of battery cell, the second allowable charging current can be directly found out from the current two-dimensional table of the second type of battery cell.

Of course, the battery management system may directly store the corresponding relationship among the charge state, the battery cell temperature and the allowable charging current, which is not limited by the present application.

In order to ensure that the determined allowable charging current is added to meet the service condition of the battery cell, the accuracy of the determined allowable charging power of the battery pack is improved. That is, step S203 specifically includes: determining a first initial allowable charge current for the first class of cells based on the first state of charge and the first temperature value; the first allowable charging current is calculated based on the first initial allowable charging current and the aging coefficient of the first type of cell. The step S204 specifically includes: determining a second initial allowable charge current for the second type of cell based on the second state of charge and the second temperature value; the second allowable charge current is calculated based on the second initial allowable charge current and the aging coefficient of the second type of cell.

It is understood that the first initial allowable charging current may be a table look-up current value obtained by a two-dimensional current table of the first type of battery cell, and the aging coefficient of the first type of battery cell is related to the current time of use of the first type of battery cell. It should be noted that, the battery core can be subjected to aging test when leaving the factory, so as to obtain the aging coefficients corresponding to the battery core under different use time lengths. For example, the values of the aging coefficients may be 0.8, 0.9. And finally, multiplying the first initial allowable charging current by the corresponding aging coefficient to obtain the first allowable charging current. Accordingly, the second initial allowable charging current may also be a table look-up current value obtained by a two-dimensional current meter of the second type of battery cell, and the aging coefficient of the second type of battery cell is related to the current use time of the second type of battery cell. For example, the values of the aging coefficients may be 0.6, 0.9. And finally, multiplying the second initial allowable charging current by the corresponding aging coefficient to obtain the second allowable charging current.

After the first allowable charging current of the first type of battery cell and the second allowable charging current of the second type of battery cell are obtained, the allowable charging power included in the battery can be calculated in step S205. When calculating the allowable charge power of the battery pack, the allowable charge current of the battery pack is the charge current having the smallest value among the first allowable charge current and the second allowable charge current. The specific formula for calculating the allowable charge power of the battery pack is as follows:

Allowable charge power of the battery pack = allowable charge current of the battery pack (open circuit voltage of the first type of cell + open circuit voltage of the second type of cell;

where the allowable charge current of the battery pack=min (first allowable charge current, second allowable charge current).

The open circuit voltage is the terminal voltage of the battery in the open circuit state. The open circuit voltage is related to the type of cell and the current state of charge. After the battery management system obtains the state of charge of the battery cell, the open circuit voltage of the battery cell can be obtained through a corresponding relation curve of the battery cell (wherein the relation curve is a curve which is predetermined to represent the open circuit voltage and the state of charge of the battery cell). For example, after the first state of charge of the first type of cell is obtained, an open circuit voltage of the first type of cell is determined based on a relationship curve of the first type of cell. After the second charge state of the second type of battery cell is obtained, determining the open circuit voltage of the second type of battery cell based on the relation curve of the second type of battery cell.

In order to ensure that the determined open-circuit voltage is added to meet the service condition of the battery cell, the accuracy of the determined allowable charging power of the battery pack is improved. That is, the open circuit voltage of the first type of cell is determined by the steps comprising: determining an initial open circuit voltage of the first type of cell based on the first state of charge; the open circuit voltage of the first type of cell is determined based on the initial open circuit voltage of the first type of cell and the aging coefficient of the first type of cell. Determining the open circuit voltage of the second type of cell by: determining an initial open circuit voltage of the second type of cell based on the second state of charge; the open circuit voltage of the second type of cell is determined based on the initial open circuit voltage of the second type of cell and the aging coefficient of the second type of cell.

It will be appreciated that the initial open circuit voltage of the first type of cell may be determined by a relationship curve of the first type of cell, and the aging coefficient of the first type of cell is related to the current time of use of the first type of cell. And finally, multiplying the initial open-circuit voltage of the first type of battery cells by the aging coefficient corresponding to the initial open-circuit voltage of the first type of battery cells to obtain the open-circuit voltage of the first type of battery cells. Accordingly, the initial open circuit voltage of the second type of battery cell may be determined by the relationship curve of the second type of battery cell, and the aging coefficient of the second type of battery cell is related to the current use time of the second type of battery cell. And finally, multiplying the initial open-circuit voltage of the second type of battery cells by the aging coefficient corresponding to the initial open-circuit voltage of the second type of battery cells to obtain the open-circuit voltage of the second type of battery cells.

It should be noted that the above description is only about two types of battery cells, and the allowable charge power estimation method provided by the embodiment of the application is also applicable to three types of battery cells and four types of battery cells.

It is understood that the battery management system provided by the embodiment of the present application may also apply the allowable discharge power estimation method and the allowable charge power estimation method at the same time, which is not limited to the present application.

Referring to fig. 5, based on the same inventive concept, an embodiment of the present application further provides a battery cell control device 300, which includes a first obtaining module 301, a first determining module 302, and a calculating module 303.

The first obtaining module 301 is configured to obtain a first state of charge and a first temperature value of a first type of battery cell in a battery pack, and obtain a second state of charge and a second temperature value of a second type of battery cell in the battery pack.

The first determining module 302 is configured to determine a first allowable discharge current of the first class of cells based on the first state of charge and the first temperature value; and determining a second allowable discharge current for the second type of cell based on the second state of charge and the second temperature value.

The calculating module 303 is configured to calculate the allowable discharge power of the battery pack based on a discharge current having a smallest value among the first allowable discharge current and the second allowable discharge current, a cutoff voltage of the first type of battery cell, a number of battery cells of the first type of battery cell, a cutoff voltage of the second type of battery cell, and a number of battery cells of the second type of battery cell.

Optionally, the first determining module 302 is specifically configured to determine a first initial allowable discharge current of the first type of battery cell based on the first state of charge and the first temperature value; calculating the first allowable discharge current based on the first initial allowable discharge current and the aging coefficient of the first type of cell; and determining a second initial allowable discharge current for the second type of cell based on the second state of charge and the second temperature value; the second allowable discharge current is calculated based on the second initial allowable discharge current and the aging coefficient of the second type of cell.

Optionally, the apparatus further comprises: a second acquisition module 304, a second determination module 305, and an update module 306.

The second obtaining module 304 is configured to obtain a first voltage value of the first type of battery cell; and obtaining a second voltage value of the second type of battery cell.

A second determining module 305 is configured to determine an adjusted discharge power of the battery pack based on the voltage value, where the second determining module is specifically configured to determine a first adjusted discharge power of the battery pack based on the first voltage value; and determining a second adjusted discharge power of the battery pack based on the second voltage value.

The updating module 306 is configured to update the allowable discharge power of the battery pack to a discharge power with a minimum value of the first adjusted discharge power and the second adjusted discharge power.

Optionally, the second determining module 305 is specifically configured to take the allowable discharge power of the battery pack as the adjusted discharge power when the voltage value is not less than a preset adjustment threshold.

Optionally, the second determining module 305 is specifically configured to determine a reduction ratio of the allowable discharge power of the battery pack when the voltage value is less than the preset adjustment threshold; wherein, the allowable discharge power of the battery pack is reduced in proportion to the voltage value compared with the preset adjustment threshold; the adjusted discharge power is determined based on the reduction ratio and an allowable discharge power of the battery pack.

Optionally, the second determining module 305 is specifically configured to determine a reduction ratio of the allowable discharge power of the battery pack when the voltage value is smaller than the preset adjustment threshold and the voltage value is greater than the cutoff voltage of the battery cell corresponding to the voltage value; wherein, the allowable discharge power of the battery pack is reduced in proportion to the voltage value compared with the preset adjustment threshold; or when the voltage value is smaller than the preset adjustment threshold value and the voltage value is smaller than the cut-off voltage of the battery cell corresponding to the voltage value, determining the reduction ratio of the allowable discharge power of the battery pack; the allowable discharge power of the battery pack is reduced in proportion to the cut-off voltage of the battery cell corresponding to the voltage value, which is the same as that of the preset adjustment threshold; the adjusted discharge power is determined based on the reduction ratio and an allowable discharge power of the battery pack.

Referring to fig. 6, based on the same inventive concept, an embodiment of the present application further provides a battery cell control device 400, which includes an obtaining module 401, a first determining module 402, and a calculating module 403.

An obtaining module 401, configured to obtain a first state of charge and a first temperature value of a first type of battery cell in a battery pack; and obtaining a second state of charge and a second temperature value of a second type of battery cells in the battery pack.

A first determining module 402, configured to determine a first allowable charging current of the first class of cells based on the first state of charge and the first temperature value; and determining a second allowable charge current for the second type of cell based on the second state of charge and the second temperature value.

A calculating module 403, configured to calculate the allowable charging power of the battery pack based on a charging current with a smallest value of the first allowable charging current and the second allowable charging current, an open circuit voltage of the first type of battery cell, a number of battery cells of the first type of battery cell, an open circuit voltage of the second type of battery cell, and a number of battery cells of the second type of battery cell.

Optionally, the first determining module 402 is specifically configured to determine a first initial allowable charging current of the first type of battery cell based on the first state of charge and the first temperature value; calculating the first allowable charging current based on the first initial allowable charging current and an aging coefficient of the first type of battery cell; and determining a second initial allowable charge current for the second type of cell based on the second state of charge and the second temperature value; the second allowable charging current is calculated based on the second initial allowable charging current and the aging coefficient of the second type of cell.

Optionally, the apparatus further comprises: a second determination module 404.

The second determining module 404 is configured to determine an initial open circuit voltage of the first type of battery cell based on the first state of charge; determining an open circuit voltage of the first type of battery cell based on an initial open circuit voltage of the first type of battery cell and an aging coefficient of the first type of battery cell; and determining an initial open circuit voltage of the second type of cell based on the second state of charge; and determining the open circuit voltage of the second type of battery cell based on the initial open circuit voltage of the second type of battery cell and the aging coefficient of the second type of battery cell.

It should be noted that, since it will be clearly understood by those skilled in the art, for convenience and brevity of description, the specific working processes of the systems, apparatuses and units described above may refer to the corresponding processes in the foregoing method embodiments, which are not repeated herein.

Based on the same inventive concept, the embodiments of the present application also provide a storage medium having stored thereon a computer program, which when executed may perform the method provided in the above embodiments.

The storage media may be any available media that can be accessed by a computer or a data storage device such as a server, data center, or the like that contains an integration of one or more available media. The usable medium may be a magnetic medium (e.g., floppy disk, hard disk, tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk Solid STATE DISK (SSD)), etc.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. The above-described apparatus embodiments are merely illustrative, for example, the division of the units is merely a logical function division, and there may be other manners of division in actual implementation, and for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be through some communication interface, device or unit indirect coupling or communication connection, which may be in electrical, mechanical or other form.

Further, the units described as separate units may or may not be physically separate, and units displayed as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

Furthermore, functional modules in various embodiments of the present application may be integrated together to form a single portion, or each module may exist alone, or two or more modules may be integrated to form a single portion.

In this document, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and various modifications and variations will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for estimating allowable discharge power, comprising:

acquiring a first state of charge and a first temperature value of a first type of battery cells in a battery pack;

Acquiring a second state of charge and a second temperature value of a second type of battery cell in the battery pack;

determining a first allowable discharge current for the first class of cells based on the first state of charge and the first temperature value;

determining a second allowable discharge current for the second class of cells based on the second state of charge and the second temperature value;

And calculating allowable discharge power of the battery pack based on the discharge current with the smallest value among the first allowable discharge current and the second allowable discharge current, the cut-off voltage of the first type of battery cells, the number of battery cells of the first type of battery cells, the cut-off voltage of the second type of battery cells and the number of battery cells of the second type of battery cells.

2. The method of claim 1, wherein the determining a first allowable discharge current for the first class of cells based on the first state of charge and the first temperature value comprises:

determining a first initial allowable discharge current for the first class of cells based on the first state of charge and the first temperature value;

calculating the first allowable discharge current based on the first initial allowable discharge current and the aging coefficient of the first type of cell;

the determining a second allowable discharge current for the second type of cell based on the second state of charge and the second temperature value includes:

determining a second initial allowable discharge current for the second type of cell based on the second state of charge and the second temperature value;

the second allowable discharge current is calculated based on the second initial allowable discharge current and the aging coefficient of the second type of cell.

3. The method according to claim 1, wherein the method further comprises:

Acquiring a first voltage value of the first type of battery cell;

Acquiring a second voltage value of the second type of battery cell;

Determining an adjusted discharge power of the battery pack based on the voltage value, comprising:

Determining a first adjusted discharge power of the battery pack based on the first voltage value;

determining a second adjusted discharge power of the battery pack based on the second voltage value;

And updating the allowable discharge power of the battery pack to the discharge power with the smallest value in the first adjustment discharge power and the second adjustment discharge power.

4. The method of claim 3, wherein the determining the adjusted discharge power of the battery pack based on the voltage value comprises:

And when the voltage value is not smaller than a preset adjustment threshold value, taking the allowable discharge power of the battery pack as the adjustment discharge power.

5. The method according to claim 4, wherein the method further comprises:

When the voltage value is smaller than the preset adjustment threshold value, determining the reduction proportion of the allowable discharge power of the battery pack; wherein, the allowable discharge power of the battery pack is reduced in proportion to the voltage value compared with the preset adjustment threshold;

The adjusted discharge power is determined based on the reduction ratio and an allowable discharge power of the battery pack.

6. The method according to claim 4, wherein the method further comprises:

When the voltage value is smaller than the preset adjustment threshold value and the voltage value is larger than the cut-off voltage of the battery cell corresponding to the voltage value, determining the reduction ratio of the allowable discharge power of the battery pack; wherein, the allowable discharge power of the battery pack is reduced in proportion to the voltage value compared with the preset adjustment threshold; or (b)

When the voltage value is smaller than the preset adjustment threshold value and the voltage value is smaller than the cut-off voltage of the battery cell corresponding to the voltage value, determining the reduction ratio of the allowable discharge power of the battery pack; the allowable discharge power of the battery pack is reduced in proportion to the cut-off voltage of the battery cell corresponding to the voltage value, which is the same as that of the preset adjustment threshold;

7. A method of estimating allowable charge power, comprising:

determining a first allowable charge current for the first class of cells based on the first state of charge and the first temperature value;

determining a second allowable charge current for the second class of cells based on the second state of charge and the second temperature value;

And calculating the allowable charging power of the battery pack based on the charging current with the smallest value of the first allowable charging current and the second allowable charging current, the open circuit voltage of the first type of battery cells, the number of battery cells of the first type of battery cells, the open circuit voltage of the second type of battery cells and the number of battery cells of the second type of battery cells.

8. The method of claim 7, wherein determining a first allowable charge current for the first class of cells based on the first state of charge and the first temperature value comprises:

determining a first initial allowable charge current for the first class of cells based on the first state of charge and the first temperature value;

Calculating the first allowable charging current based on the first initial allowable charging current and an aging coefficient of the first type of battery cell;

The determining a second allowable charge current for the second type of cell based on the second state of charge and the second temperature value includes:

Determining a second initial allowable charge current for the second class of cells based on the second state of charge and the second temperature value;

The second allowable charging current is calculated based on the second initial allowable charging current and the aging coefficient of the second type of cell.

9. The method of claim 7, wherein determining the open circuit voltage of the first type of cell comprises:

determining an initial open circuit voltage of the first type of cell based on the first state of charge;

Determining an open circuit voltage of the first type of battery cell based on an initial open circuit voltage of the first type of battery cell and an aging coefficient of the first type of battery cell;

determining the open circuit voltage of the second type of cell by:

Determining an initial open circuit voltage of the second type of cell based on the second state of charge;

And determining the open circuit voltage of the second type of battery cell based on the initial open circuit voltage of the second type of battery cell and the aging coefficient of the second type of battery cell.

10. A cell control device, comprising:

The first acquisition module is used for acquiring a first state of charge and a first temperature value of a first type of battery cells in the battery pack and acquiring a second state of charge and a second temperature value of a second type of battery cells in the battery pack;

a first determination module configured to determine a first allowable discharge current of the first class of cells based on the first state of charge and the first temperature value; and determining a second allowable discharge current for the second type of cell based on the second state of charge and the second temperature value;

and the calculating module is used for calculating the allowable discharge power of the battery pack based on the discharge current with the smallest value in the first allowable discharge current and the second allowable discharge current, the cut-off voltage of the first type of battery cells, the number of the battery cells of the first type of battery cells, the cut-off voltage of the second type of battery cells and the number of the battery cells of the second type of battery cells.

11. The apparatus of claim 10, wherein the first determining module is configured to determine a first initial allowable discharge current for the first type of cell based in particular on the first state of charge and the first temperature value; calculating the first allowable discharge current based on the first initial allowable discharge current and the aging coefficient of the first type of cell; and determining a second initial allowable discharge current for the second type of cell based on the second state of charge and the second temperature value; the second allowable discharge current is calculated based on the second initial allowable discharge current and the aging coefficient of the second type of cell.

12. The apparatus of claim 10, wherein the apparatus further comprises:

the second acquisition module is used for acquiring a first voltage value of the first type of battery cell; obtaining a second voltage value of the second type of battery cell;

the second determining module is used for determining the adjusted discharge power of the battery pack based on the voltage value, wherein the second determining module is specifically used for determining the first adjusted discharge power of the battery pack based on the first voltage value; and determining a second adjusted discharge power of the battery pack based on the second voltage value;

and the updating module is used for updating the allowable discharge power of the battery pack into the discharge power with the minimum value in the first adjustment discharge power and the second adjustment discharge power.

13. The apparatus of claim 12, wherein the second determining module is specifically configured to take the allowable discharge power of the battery pack as the adjusted discharge power when the voltage value is not less than a preset adjustment threshold.

14. The apparatus of claim 13, wherein the second determining module is specifically configured to determine a reduction ratio of allowable discharge power of the battery pack when the voltage value is less than the preset adjustment threshold; wherein, the allowable discharge power of the battery pack is reduced in proportion to the voltage value compared with the preset adjustment threshold; the adjusted discharge power is determined based on the reduction ratio and an allowable discharge power of the battery pack.

15. The apparatus of claim 13, wherein the second determining module is specifically configured to determine a reduction ratio of allowable discharge power of the battery pack when the voltage value is less than the preset adjustment threshold and the voltage value is greater than a cutoff voltage of a cell corresponding to the voltage value; wherein, the allowable discharge power of the battery pack is reduced in proportion to the voltage value compared with the preset adjustment threshold; or when the voltage value is smaller than the preset adjustment threshold value and the voltage value is smaller than the cut-off voltage of the battery cell corresponding to the voltage value, determining the reduction ratio of the allowable discharge power of the battery pack; the allowable discharge power of the battery pack is reduced in proportion to the cut-off voltage of the battery cell corresponding to the voltage value, which is the same as that of the preset adjustment threshold; the adjusted discharge power is determined based on the reduction ratio and an allowable discharge power of the battery pack.

16. A cell control device, comprising:

The acquisition module is used for acquiring a first state of charge and a first temperature value of a first type of battery cells in the battery pack; obtaining a second state of charge and a second temperature value of a second type of battery cells in the battery pack;

A first determining module configured to determine a first allowable charging current for the first class of cells based on the first state of charge and the first temperature value; and determining a second allowable charge current for the second type of cell based on the second state of charge and the second temperature value;

And the calculating module is used for calculating the allowable charging power of the battery pack based on the charging current with the smallest value in the first allowable charging current and the second allowable charging current, the open-circuit voltage of the first type of battery cells, the number of battery cells of the first type of battery cells, the open-circuit voltage of the second type of battery cells and the number of battery cells of the second type of battery cells.

17. The apparatus of claim 16, wherein the first determining module is configured to determine a first initial allowable charging current for the first type of cell based in particular on the first state of charge and the first temperature value; calculating the first allowable charging current based on the first initial allowable charging current and an aging coefficient of the first type of battery cell; and determining a second initial allowable charge current for the second type of cell based on the second state of charge and the second temperature value; the second allowable charging current is calculated based on the second initial allowable charging current and the aging coefficient of the second type of cell.

18. The apparatus of claim 16, wherein the apparatus further comprises: a second determination module;

The second determining module is used for determining an initial open circuit voltage of the first type of battery cell based on the first charge state; determining an open circuit voltage of the first type of battery cell based on an initial open circuit voltage of the first type of battery cell and an aging coefficient of the first type of battery cell; and determining an initial open circuit voltage of the second type of cell based on the second state of charge; and determining the open circuit voltage of the second type of battery cell based on the initial open circuit voltage of the second type of battery cell and the aging coefficient of the second type of battery cell.

19. A battery management system, comprising: the device comprises a processor and a memory, wherein the processor is connected with the memory;

The memory is used for storing programs;

The processor being configured to execute a program stored in the memory for performing the method of any one of claims 1-6.

20. A battery management system, comprising: the device comprises a processor and a memory, wherein the processor is connected with the memory;

The memory is used for storing programs;

The processor being configured to execute a program stored in the memory, performing the method of any one of claims 7-9.

21. A storage medium having stored thereon a computer program which, when run by a computer, performs the method of any of claims 1-6.

22. A storage medium having stored thereon a computer program which, when run by a computer, performs the method of any of claims 7-9.