Method, device and equipment for determining voltage difference of battery system

Abstract

The embodiments of the present application provide a method, device, and apparatus for determining the voltage difference of a battery system. The method includes: obtaining the number of single cells, the number of single cells connected in series, and the number of single cells connected in parallel in the battery system; obtaining the maximum remaining power, minimum remaining power, maximum temperature, and minimum temperature of the battery system; obtaining the corresponding relationship between temperature, remaining power, and internal resistance; determining the maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining powers based on the maximum remaining power, minimum remaining power, maximum temperature, minimum temperature, and the corresponding relationship; and determining the dynamic voltage difference of the battery system based on the maximum internal resistance difference, the number of single cells, the number of single cells connected in series, the number of single cells connected in parallel, and the test current. This improves the efficiency of determining the voltage difference of the battery system.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of battery technology, and in particular to a method, device, and apparatus for determining a voltage difference in a battery system. Background Art

[0002] A battery system can include multiple cells connected in series and / or in parallel. Different cells have varying performance characteristics, such as capacity, power, and self-discharge. This inconsistency can lead to significant voltage differences within the battery system, impacting the system's capacity, internal resistance, and lifespan.

[0003] To ensure the overall performance of the battery system, manufacturers test the battery system's pressure differential before it leaves the factory. In related technologies, this method typically involves charging and discharging the highest- and lowest-capacity cells in the battery system, obtaining the corresponding end-of-charge and discharge pressure differentials, and determining this pressure differential as the battery system's pressure differential. This process, which requires charging and discharging each cell in the battery system, is complex and inefficient in determining the battery system's pressure differential. Summary of the Invention

[0004] The embodiments of the present application provide a method, apparatus, and device for determining the pressure difference of a battery system, which solve the problem of low efficiency in determining the pressure difference of a battery system.

[0005] In a first aspect, an embodiment of the present application provides a method for determining a voltage difference of a battery system, comprising:

[0006] Obtain the number of single cells, the number of single cells in series, and the number of single cells in parallel in the battery system;

[0007] Obtaining the maximum remaining power, minimum remaining power, maximum temperature, and minimum temperature of the battery system;

[0008] Obtain the corresponding relationship between temperature, remaining power and internal resistance;

[0009] determining, according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, and the corresponding relationship, a maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining powers;

[0010] The dynamic voltage difference of the battery system is determined according to the maximum internal resistance difference, the number of the single cells, the number of the single cells connected in series, the number of the single cells connected in parallel, and the test current.

[0011] In one possible implementation, obtaining the maximum remaining power and the minimum remaining power of the battery system includes:

[0012] Obtaining a time difference between a current moment and a production moment of a single battery in the battery system;

[0013] Obtain the maximum and minimum self-discharge rates of a single battery per unit time;

[0014] determining a minimum remaining capacity of the battery system according to the time difference and the maximum self-discharge rate;

[0015] The maximum remaining capacity of the battery system is determined according to the time difference and the minimum self-discharge rate.

[0016] In a possible implementation, obtaining the maximum self-discharge rate and the minimum self-discharge rate of a single battery within a unit time includes:

[0017] Obtaining M average self-discharge rates of a plurality of M sample single cells within a plurality of historical unit time periods, where M is an integer greater than 1;

[0018] A maximum value among the M average self-discharge rates is determined as the maximum self-discharge rate, and a minimum value among the M average self-discharge rates is determined as the minimum self-discharge rate.

[0019] In a possible implementation, the corresponding relationship includes:

[0020] The first correspondence between temperature, remaining power and maximum internal resistance of charging;

[0021] A second correspondence between temperature, remaining capacity, and minimum internal resistance for charging;

[0022] The third correspondence between temperature, remaining capacity and maximum internal resistance of discharge;

[0023] The fourth correspondence between temperature, remaining capacity and minimum internal resistance for discharge.

[0024] In a possible implementation, determining, based on the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, and the corresponding relationship, a maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining powers includes:

[0025] determining eight maximum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the first corresponding relationship, and the third corresponding relationship;

[0026] determining eight minimum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the second corresponding relationship, and the fourth corresponding relationship;

[0027] The difference between the maximum value of the eight maximum internal resistances and the minimum value of the eight minimum internal resistances is determined as the maximum internal resistance difference.

[0028] In one possible implementation, determining the dynamic voltage difference of the battery system according to the maximum internal resistance difference, the number of single cells, the number of single cells connected in series, the number of single cells connected in parallel, and the test current includes:

[0029] Determining the internal resistance range of the battery system according to the maximum internal resistance difference, the number of the single cells, the number of the single cells connected in series, and the number of the single cells connected in parallel;

[0030] The dynamic voltage difference of the battery system is determined according to the internal resistance extreme difference and the test current.

[0031] In a possible implementation, determining the internal resistance range of the battery system according to the maximum internal resistance difference, the number of single cells, the number of single cells connected in series, and the number of single cells connected in parallel includes:

[0032] If the number of the single cells is the same as the number of the single cells connected in series, the maximum internal resistance difference is determined as the internal resistance range;

[0033] If the number of single cells and the number of single cells connected in series are different, the internal resistance range Rpcak=Rcell / Ncell*Npack / N is determined, where Rpcak is the internal resistance range, Rcell is the maximum internal resistance difference, Ncell is the number of single cells, Npack is the number of single cells connected in series, and N is the number of single cells connected in parallel.

[0034] In a second aspect, an embodiment of the present application provides a device for determining a voltage difference in a battery system, the device comprising:

[0035] The first acquisition module is used to obtain the number of single cells, the number of single cells connected in series, and the number of single cells connected in parallel in the battery system;

[0036] A second acquisition module is used to obtain the maximum remaining power, minimum remaining power, maximum temperature and minimum temperature of the battery system;

[0037] The third acquisition module is used to obtain the corresponding relationship between temperature, remaining power and internal resistance;

[0038] a first determining module, configured to determine, based on the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, and the corresponding relationship, a maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining powers;

[0039] The second determination module is configured to determine the dynamic pressure difference of the battery system according to the maximum internal resistance difference, the number of the single cells, the number of the single cells connected in series, the number of the single cells connected in parallel, and the test current.

[0040] In a possible implementation manner, the second acquisition module is specifically configured to:

[0041] Obtaining a time difference between a current moment and a production moment of a single battery in the battery system;

[0042] Obtain the maximum and minimum self-discharge rates of a single battery per unit time;

[0043] determining a minimum remaining capacity of the battery system according to the time difference and the maximum self-discharge rate;

[0044] The maximum remaining capacity of the battery system is determined according to the time difference and the minimum self-discharge rate.

[0045] In a possible implementation manner, the second acquisition module is specifically configured to:

[0046] Obtaining M average self-discharge rates of a plurality of M sample single cells within a plurality of historical unit time periods, where M is an integer greater than 1;

[0047] A maximum value among the M average self-discharge rates is determined as the maximum self-discharge rate, and a minimum value among the M average self-discharge rates is determined as the minimum self-discharge rate.

[0048] In a possible implementation, the corresponding relationship includes:

[0049] The first correspondence between temperature, remaining power and maximum internal resistance of charging;

[0050] A second correspondence between temperature, remaining capacity, and minimum internal resistance for charging;

[0051] The third correspondence between temperature, remaining capacity and maximum internal resistance of discharge;

[0052] The fourth correspondence between temperature, remaining capacity and minimum internal resistance for discharge.

[0053] In a possible implementation manner, the first determining module is specifically configured to:

[0054] determining eight maximum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the first corresponding relationship, and the third corresponding relationship;

[0055] determining eight minimum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the second corresponding relationship, and the fourth corresponding relationship;

[0056] The difference between the maximum value of the eight maximum internal resistances and the minimum value of the eight minimum internal resistances is determined as the maximum internal resistance difference.

[0057] In a possible implementation manner, the second determining module is specifically configured to:

[0058] Determining the internal resistance range of the battery system according to the maximum internal resistance difference, the number of the single cells, the number of the single cells connected in series, and the number of the single cells connected in parallel;

[0059] The dynamic voltage difference of the battery system is determined according to the internal resistance extreme difference and the test current.

[0060] In a possible implementation manner, the second determining module is specifically configured to:

[0061] If the number of the single cells is the same as the number of the single cells connected in series, the maximum internal resistance difference is determined as the internal resistance range;

[0062] If the number of single cells and the number of single cells connected in series are different, the internal resistance range Rpcak=Rcell / Ncell*Npack / N is determined, where Rpcak is the internal resistance range, Rcell is the maximum internal resistance difference, Ncell is the number of single cells, Npack is the number of single cells connected in series, and N is the number of single cells connected in parallel.

[0063] In a third aspect, an embodiment of the present application provides a device for determining a voltage difference in a battery system, comprising:

[0064] at least one processor; and

[0065] a memory communicatively connected to the at least one processor; wherein,

[0066] The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform any method described in the first aspect.

[0067] In a fourth aspect, an embodiment of the present application provides a non-transitory computer-readable storage medium storing computer instructions, wherein the computer instructions are used to enable the computer to execute the method according to any one of the first aspects.

[0068] In a fifth aspect, an embodiment of the present application provides a computer program product, comprising a computer program, which, when executed by a processor, implements the method according to any one of the first aspects.

[0069] The present invention provides a method, device, and apparatus for determining the pressure differential of a battery system. Based on the corresponding relationship between the temperature, remaining charge, and internal resistance of multiple battery cells, the method determines the maximum internal resistance difference of the battery system at different temperatures and remaining charges. Furthermore, the method determines the dynamic pressure differential of the battery system based on this maximum internal resistance difference and the characteristics of the battery system (e.g., the number of battery cells and the number of battery cells connected in series). This process eliminates the need to perform charge and discharge tests on the battery cells in the system, simplifying the testing process and improving the efficiency of determining the pressure differential of the battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 A schematic diagram of an application scenario provided in an embodiment of the present application;

[0071] Figure 2 A flow chart of a method for determining a battery system pressure difference according to an embodiment of the present application;

[0072] Figure 3A A schematic diagram of a battery system single cell connection method provided in an embodiment of the present application;

[0073] Figure 3B A structural diagram of another battery system single cell connection method provided in an embodiment of the present application;

[0074] Figure 4 A flow chart of another method for determining a battery system pressure difference provided in an embodiment of the present application;

[0075] Figure 5 A schematic structural diagram of a device for determining a pressure difference in a battery system provided in an embodiment of the present application;

[0076] Figure 6 A schematic diagram of the structure of a battery system pressure difference determination device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0077] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0078] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0079] Figure 1 This is a schematic diagram of the battery system provided in the embodiment of the present application. Figure 1 A battery system includes multiple single cells. These cells can be connected in series or in parallel to form a battery system. By performing charge and discharge tests on a single cell, the charge and discharge internal resistance of the cell can be determined.

[0080] In related technologies, the method for testing the battery system's differential pressure is to charge and discharge the highest-capacity and lowest-capacity individual cells in the battery system, respectively, to obtain the corresponding differential pressure at the end of charge and discharge, which is the differential pressure of the battery system. This process requires charging and discharging each individual cell in the battery system for each test, which is complex and results in low efficiency in determining the battery system's differential pressure.

[0081] In the embodiments of the present application, the maximum internal resistance difference of the battery system at different temperatures and different remaining charges is determined based on the corresponding relationship between the temperature, remaining charge, and internal resistance of multiple single cells. Furthermore, the dynamic differential pressure of the battery system is determined based on this maximum internal resistance difference and the characteristics of the battery system (e.g., the number of single cells in the battery system, the number of single cells connected in series, and the number of single cells connected in parallel). In this process, the battery system does not need to be charged or discharged, which simplifies the testing process and improves the efficiency of determining the differential pressure of the battery system.

[0082] Figure 2 This is a flow chart of the method for determining the battery system pressure difference provided in the embodiment of the present application. Figure 2 , the method may include:

[0083] S201: Obtain the number of single cells, the number of single cells connected in series, and the number of single cells connected in parallel in a battery system.

[0084] The embodiment of the present application may be implemented by a device for determining a battery system pressure difference, which may be implemented by software or a combination of software and hardware.

[0085] The battery system may include a plurality of single cells. For example, the battery system may include six single cells.

[0086] The number of single cells in series refers to the maximum number of single cells connected in series in a battery system. The number of single cells in parallel refers to the number of parallel circuits in a battery system. Figure 3A-3B , the determination of the number of single cells connected in series and the number of batteries connected in parallel is explained.

[0087] Figure 3A This is a structural diagram of a battery system cell connection method provided in an embodiment of the present application. Figure 3A , a battery system has a total of 3 single cells. 3 single cells are connected in series in a string, so the number of single cells in the battery system is 3, and the number of single cells in parallel is 1.

[0088] Figure 3B This is a schematic diagram of another battery system cell connection method provided in an embodiment of the present application. A battery system has a total of six single cells. Two single cells are connected in series, forming a string, for a total of three battery strings, which are then connected in parallel. Therefore, the battery system has two single cells connected in series and three single cells connected in parallel.

[0089] S202: Obtain the maximum remaining power, minimum remaining power, maximum temperature, and minimum temperature of the battery system.

[0090] The maximum remaining capacity is the maximum value of the remaining capacity after discharging multiple single batteries.

[0091] The maximum remaining capacity is the minimum value of the remaining capacity after discharging multiple single batteries.

[0092] The maximum temperature is the maximum temperature of the battery cell when the battery system is working.

[0093] The minimum temperature is the lowest temperature of the battery cell when the battery system is working.

[0094] The maximum remaining capacity of the battery system can be obtained in the following ways: obtaining the time difference between the current moment and the production moment of the single battery in the battery system; obtaining the minimum self-discharge rate of the single battery in unit time; and determining the maximum remaining capacity of the battery system based on the time difference and the minimum self-discharge rate.

[0095] The self-discharge rate is the percentage of battery self-discharge to the total battery capacity per unit time. The unit time can be 1 month.

[0096] For example, a battery with a capacity of 12 Ah has an SOC of 90% when it leaves the factory and self-discharges 0.36 Ah within one month. The self-discharge rate is 0.36 / (12*90%)=3.3%.

[0097] Maximum remaining capacity = 100% - time difference * minimum self-discharge rate.

[0098] The minimum remaining capacity of the battery system can be obtained in the following ways: obtaining the time difference between the current moment and the production moment of the single battery in the battery system; obtaining the maximum self-discharge rate of the single battery in unit time; and determining the minimum remaining capacity of the battery system based on the time difference and the maximum self-discharge rate.

[0099] Minimum remaining capacity = 100% - time difference * maximum self-discharge rate.

[0100] For example, in a battery system, the maximum self-discharge rate of a single cell in a month is 30%, and the minimum self-discharge rate is 10%. The time difference between the test time and the production time of the single cells in the battery system is 2 months. Therefore, the minimum remaining capacity of the battery system = 100% - time difference * maximum self-discharge rate = 100% - 2 * 30% = 40%, and the maximum remaining capacity = 100% - time difference * minimum self-discharge rate = 100% - 2 * 10% = 80%.

[0101] S203 : Obtain the corresponding relationship between temperature, remaining capacity (SOC) and internal resistance.

[0102] The corresponding relationships may include: a first corresponding relationship between temperature, remaining power and maximum charging internal resistance; a second corresponding relationship between temperature, remaining power and minimum charging internal resistance; a third corresponding relationship between temperature, remaining power and maximum discharging internal resistance; and a fourth corresponding relationship between temperature, remaining power and minimum discharging internal resistance.

[0103] The corresponding relationship can include multiple remaining capacities, multiple temperatures, and multiple internal resistances. The remaining capacities can range from 5% to 95%, with the difference between two adjacent remaining capacities being 5%. The temperature range can range from -20°C to 40°C, with the difference between two adjacent temperatures being 10°C. The internal resistance can include both charging and discharging resistances.

[0104] For example, the corresponding relationship between "temperature-SOC-maximum charging internal resistance" of a single battery is shown in Table 1:

[0105] Table 1

[0106]

[0107] S204 : Determine a maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining capacities based on the maximum remaining capacity, the minimum remaining capacity, the maximum temperature, the minimum temperature, and the corresponding relationship.

[0108] The maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining capacities can be determined as follows: eight maximum internal resistances are determined based on the maximum remaining capacities, the minimum remaining capacities, the highest temperature, the lowest temperature, the first corresponding relationship, and the third corresponding relationship; eight minimum internal resistances are determined based on the maximum remaining capacities, the minimum remaining capacities, the highest temperature, the lowest temperature, the second corresponding relationship, and the fourth corresponding relationship; and the difference between the maximum value of the eight maximum internal resistances and the minimum value of the eight minimum internal resistances is determined as the maximum internal resistance difference.

[0109] The 8 maximum internal resistances include: the maximum value of the charging resistance and the maximum value of the discharging resistance under the conditions of the highest temperature and the maximum remaining capacity; the maximum value of the charging resistance and the maximum value of the discharging resistance under the conditions of the highest temperature and the minimum remaining capacity; the maximum value of the charging resistance and the maximum value of the discharging resistance under the conditions of the lowest temperature and the maximum remaining capacity; and the maximum value of the charging resistance and the maximum value of the discharging resistance under the conditions of the lowest temperature and the minimum remaining capacity.

[0110] The 8 minimum internal resistances include: the maximum value of the charging resistance and the minimum value of the discharge resistance under the conditions of maximum temperature and maximum remaining capacity; the maximum value of the charging resistance and the minimum value of the discharge resistance under the conditions of maximum temperature and minimum remaining capacity; the maximum value of the charging resistance and the minimum value of the discharge resistance under the conditions of minimum temperature and maximum remaining capacity; the maximum value of the charging resistance and the minimum value of the discharge resistance under the conditions of minimum temperature and minimum remaining capacity.

[0111] For example, in a battery system, the maximum remaining power is 90%, the minimum remaining power is 60%, the maximum temperature is 40°C, and the minimum temperature is 20°C. Based on the maximum remaining power, minimum remaining power, maximum temperature, minimum temperature and their corresponding relationships, the 16 internal resistance values ​​obtained are shown in Table 2:

[0112] Table 2

[0113]

[0114] As shown in Table 2, according to the maximum remaining power, minimum remaining power, maximum temperature, minimum temperature, the first corresponding relationship and the third corresponding relationship, the 8 maximum internal resistances are determined as: R 11 、R 12 、R 13 、R 14 、R 31 、R 32 、R 33 and R 34 According to the maximum remaining power, minimum remaining power, maximum temperature, minimum temperature, the second corresponding relationship and the fourth corresponding relationship, the 8 minimum internal resistances are determined as: R 21 、R 22 、R 23 、R 24 、R41 、R 42 、R 43 and R 44 .

[0115] Assume that the maximum value of all charging maximum internal resistance and discharge maximum internal resistance is R11, and the minimum value of all charging minimum internal resistance and discharge minimum internal resistance is R 43 According to the maximum value R 11 and the minimum value R 43 , determine the maximum internal resistance difference is Rcell=R 11 -R 43 .

[0116] S205 , determining the dynamic voltage difference of the battery system according to the maximum internal resistance difference, the number of single cells, the number of single cells connected in series, the number of single cells connected in parallel, and the test current.

[0117] The dynamic voltage difference of the battery system can be determined in the following ways: the internal resistance range of the battery system is determined based on the maximum internal resistance difference, the number of single cells, the number of single cells in series, and the number of single cells in parallel; the dynamic voltage difference of the battery system is determined based on the internal resistance range and the test current.

[0118] If the number of single cells and the number of single cells connected in series are the same, the maximum internal resistance difference is determined as the internal resistance range.

[0119] If the number of single cells and the number of single cells in series are different, the internal resistance range Rpcak = Rcell / Ncell*Npack / N is determined, where Rpcak is the internal resistance range, Rcell is the maximum internal resistance difference, Ncell is the number of single cells, Npack is the number of single cells in series, and N is the number of single cells in parallel.

[0120] The battery system pressure difference determination method provided in the embodiment of the present application obtains the number of single cells, the number of single cells connected in series, and the number of single cells connected in parallel in the battery system; obtains the maximum remaining power, minimum remaining power, highest temperature, and lowest temperature of the battery system; obtains the corresponding relationship between temperature, remaining power, and internal resistance; determines the maximum internal resistance difference of the battery system at different temperatures and different remaining powers based on the maximum remaining power, minimum remaining power, highest temperature, lowest temperature, and the corresponding relationship; and determines the dynamic pressure difference of the battery system based on the maximum internal resistance difference, the number of single cells, the number of single cells connected in series, the number of single cells connected in parallel, and the test current. In this way, there is no need to perform charge and discharge tests on the single cells in the battery system, which simplifies the test steps and improves the efficiency of determining the pressure difference of the battery system.

[0121] Based on any of the above embodiments, Figure 4 , the detailed process of the method for determining the battery system pressure difference is explained.

[0122] Figure 4 This is a flow chart of another method for determining the pressure difference of a battery system provided in an embodiment of the present application. Figure 4 , the method may include:

[0123] S401 , obtaining the number of single cells, the number of single cells connected in series, and the number of single cells connected in parallel in a battery system.

[0124] It should be noted that the execution process of S401 can refer to the execution process of S201, and will not be repeated here.

[0125] S402: Obtain the time difference between the current time and the production time of the single battery in the battery system.

[0126] The time difference between the current time and the production time of a single battery in the battery system can be determined as follows: Based on the current time and the production time of the single battery, determine the number of days between them. Based on the number of days between them, determine the time difference = the number of days between them / 30. The current time can be the test time of the battery system.

[0127] For example, a battery system was tested on April 11th, and the individual batteries were produced on March 1st. Based on the battery system test time and the individual battery production time, the interval is 42 days. Based on the interval, the time difference is calculated as: interval / 30 = 42 / 30 = 1.4.

[0128] S403 : Obtain the maximum self-discharge rate and the minimum self-discharge rate of the single battery within a unit time.

[0129] The maximum self-discharge rate is the maximum value of the self-discharge rates obtained after multiple single batteries are discharged in a unit time.

[0130] The minimum self-discharge rate is the minimum value of the self-discharge rate obtained after multiple single batteries are discharged in a unit time.

[0131] The maximum self-discharge rate and the minimum self-discharge rate of the battery system within a unit time can be determined in the following manner: obtain M average self-discharge rates of multiple M sample single cells within multiple historical unit time periods, where M is an integer greater than 1; determine the maximum value of the M average self-discharge rates as the maximum self-discharge rate, and determine the minimum value of the M average self-discharge rates as the minimum self-discharge rate.

[0132] The unit period can be 30 days.

[0133] The average self-discharge rate is obtained under the following conditions: 25°C ± 2°C and the remaining capacity of the single battery at the time of leaving the factory (SOC0).

[0134] For example, assuming the SOC0 of a single battery is 95%, the monthly self-discharge rate of the single battery at 25°C within 6 months is shown in Table 3:

[0135] Table 3

[0136] month 1 2 3 4 5 6 Monthly self-discharge rate % 5 3 4 7 3 4

[0137] Then the average monthly self-discharge rate of this single cell is (5+3+4+7+3+4) / 6*100%=4.3%.

[0138] A maximum self-discharge rate and a minimum self-discharge rate are determined based on the values ​​of the plurality of average self-discharge rates.

[0139] For example, there are 5 single cells with an SOC0 of 95%. The average self-discharge rate at 25°C is shown in Table 4:

[0140] Table 4

[0141] Single battery 1 2 3 4 5 6 Average self-discharge rate% 5 3 7 2 5 3

[0142] According to Table 4, the maximum self-discharge rate of the single battery is 7%, and the minimum self-discharge rate is 2%.

[0143] S404: Determine the minimum remaining capacity of the battery system according to the time difference and the maximum self-discharge rate.

[0144] Minimum remaining capacity = 100% - time difference * maximum self-discharge rate.

[0145] For example, in a battery system, the maximum self-discharge rate of a single cell in a month is 5%, and the minimum self-discharge rate is 3%. The time difference between the test time and the production time of the single cells in the battery system is 2 months. Therefore, the minimum remaining capacity of the battery system = 100% - time difference * maximum self-discharge rate = 100% - 2 * 5% = 90%.

[0146] S405 : Determine the maximum remaining capacity of the battery system according to the time difference and the minimum self-discharge rate.

[0147] Maximum remaining capacity = 100% - time difference * minimum self-discharge rate.

[0148] For example, in a battery system, the maximum self-discharge rate of a single cell in a month is 5%, and the minimum self-discharge rate is 3%. The time difference between the test time and the production time of the single cells in the battery system is 2 months. Therefore, the maximum remaining capacity of the battery system = 100% - time difference * minimum self-discharge rate = 100% - 2 * 3% = 94%.

[0149] S406: Obtain the maximum temperature and the minimum temperature of the battery system.

[0150] The maximum temperature is the maximum temperature of the battery cell when the battery system is working.

[0151] The minimum temperature is the lowest temperature of the battery cell when the battery system is working.

[0152] S407: Obtain the corresponding relationship between temperature, remaining power and internal resistance.

[0153] The corresponding relationships include: a first corresponding relationship between temperature, remaining power and maximum charging internal resistance; a second corresponding relationship between temperature, remaining power and minimum charging internal resistance; a third corresponding relationship between temperature, remaining power and maximum discharging internal resistance; and a fourth corresponding relationship between temperature, remaining power and minimum discharging internal resistance.

[0154] S408 : Determine eight maximum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the first corresponding relationship, and the third corresponding relationship.

[0155] The 8 maximum internal resistances include: the maximum value of the charging resistance and the maximum value of the discharging resistance under the conditions of the highest temperature and the maximum remaining capacity; the maximum value of the charging resistance and the maximum value of the discharging resistance under the conditions of the highest temperature and the minimum remaining capacity; the maximum value of the charging resistance and the maximum value of the discharging resistance under the conditions of the lowest temperature and the maximum remaining capacity; and the maximum value of the charging resistance and the maximum value of the discharging resistance under the conditions of the lowest temperature and the minimum remaining capacity.

[0156] For example, in a battery system, the maximum remaining power is 90%, the minimum remaining power is 60%, the maximum temperature is 40°C, and the minimum temperature is 20°C. Based on the temperature, remaining power, the first correspondence, and the third correspondence, the maximum internal resistance is shown in Table 5:

[0157] Table 5

[0158]

[0159] S409 , determining eight minimum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the second corresponding relationship, and the fourth corresponding relationship.

[0160] The 8 minimum internal resistances include: the maximum value of the charging resistance and the minimum value of the discharge resistance under the conditions of maximum temperature and maximum remaining capacity; the maximum value of the charging resistance and the minimum value of the discharge resistance under the conditions of maximum temperature and minimum remaining capacity; the maximum value of the charging resistance and the minimum value of the discharge resistance under the conditions of minimum temperature and maximum remaining capacity; the maximum value of the charging resistance and the minimum value of the discharge resistance under the conditions of minimum temperature and minimum remaining capacity.

[0161] For example, in a battery system, the maximum remaining power is 90%, the minimum remaining power is 60%, the maximum temperature is 40°C, and the minimum temperature is 20°C. Based on the temperature, remaining power, the second correspondence, and the fourth correspondence, the minimum internal resistance is shown in Table 6:

[0162] Table 6

[0163]

[0164] S410 : Determine the difference between the maximum value among the eight maximum internal resistances and the minimum value among the eight minimum internal resistances as the maximum internal resistance difference.

[0165] The maximum internal resistance difference can be determined as follows: Based on the eight maximum internal resistances and the eight minimum internal resistances, determine the maximum value among the eight maximum internal resistances and the minimum value among the eight minimum internal resistances. The difference between the maximum and minimum values ​​is determined as the maximum internal resistance difference.

[0166] For example, according to Tables 3 and 4, the maximum value of the eight maximum internal resistances is 1.3, and the minimum value of the eight minimum internal resistances is 0.7. The maximum internal resistance difference is determined based on the difference between the maximum and minimum values, specifically Rcell = 1.3 mΩ - 0.7 mΩ = 0.6 mΩ.

[0167] S411 , determining the internal resistance range of the battery system according to the maximum internal resistance difference, the number of single cells, the number of single cells connected in series, and the number of single cells connected in parallel.

[0168] The internal resistance range can be determined as follows: if the number of single cells and the number of single cells connected in series are the same, the maximum internal resistance difference is determined as the internal resistance range.

[0169] If the number of single cells and the number of single cells in series are different, the internal resistance range Rpcak = Rcell / Ncell*Npack / N is determined, where Rpcak is the internal resistance range, Rcell is the maximum internal resistance difference, Ncell is the number of single cells, Npack is the number of single cells in series, and N is the number of single cells in parallel.

[0170] S412: Determine the dynamic voltage difference of the battery system according to the internal resistance extreme difference and the test current.

[0171] The test current is the current used when testing the battery system.

[0172] The dynamic voltage difference of the battery system is specifically V=I*Rpack.

[0173] exist Figure 4In the illustrated embodiment, the maximum and minimum values ​​of the charging and discharging internal resistances under certain temperature and remaining charge conditions are determined based on the corresponding relationships among the temperature, remaining charge, and internal resistance of multiple battery cells. The maximum and minimum values ​​are then determined from these maximum and minimum values. The internal resistance range of the battery system is determined based on the difference between the maximum and minimum values, the number of battery cells in the battery system, the number of battery cells connected in series, and the number of battery cells connected in parallel. The battery system differential pressure is then determined based on the internal resistance range and the test current. This eliminates the need to perform charge and discharge tests on the individual batteries in the battery system, simplifies the testing process, and improves the efficiency of determining the battery system differential pressure.

[0174] Figure 5 This is a schematic diagram of a device for determining a pressure difference in a battery system according to an embodiment of the present application. Figure 5 , the battery system pressure difference determination device 10 may include:

[0175] A first acquisition module 11 is used to obtain the number of single cells, the number of single cells connected in series, and the number of single cells connected in parallel in the battery system;

[0176] The second acquisition module 12 is used to obtain the maximum remaining power, minimum remaining power, maximum temperature and minimum temperature of the battery system;

[0177] The third acquisition module 13 is used to obtain the corresponding relationship between temperature, remaining power and internal resistance;

[0178] A first determining module 14 is configured to determine a maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining capacities based on the maximum remaining capacity, the minimum remaining capacity, the maximum temperature, the minimum temperature, and the corresponding relationship;

[0179] The second determining module 15 is configured to determine the dynamic voltage difference of the battery system according to the maximum internal resistance difference, the number of the single cells, the number of the single cells connected in series, the number of the single cells connected in parallel, and the test current.

[0180] The pressure difference determination device for the battery system provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0181] In a possible implementation, the second acquisition module 12 is specifically configured to:

[0182] Obtaining a time difference between a current moment and a production moment of a single battery in the battery system;

[0183] Obtain the maximum and minimum self-discharge rates of a single battery per unit time;

[0184] determining a minimum remaining capacity of the battery system according to the time difference and the maximum self-discharge rate;

[0185] The maximum remaining capacity of the battery system is determined according to the time difference and the minimum self-discharge rate.

[0186] In a possible implementation, the second acquisition module 12 is specifically configured to:

[0187] Obtaining M average self-discharge rates of a plurality of M sample single cells within a plurality of historical unit time periods, where M is an integer greater than 1;

[0188] A maximum value among the M average self-discharge rates is determined as the maximum self-discharge rate, and a minimum value among the M average self-discharge rates is determined as the minimum self-discharge rate.

[0189] In a possible implementation, the corresponding relationship includes:

[0190] The first correspondence between temperature, remaining power and maximum internal resistance of charging;

[0191] A second correspondence between temperature, remaining capacity, and minimum internal resistance for charging;

[0192] The third correspondence between temperature, remaining capacity and maximum internal resistance of discharge;

[0193] The fourth correspondence between temperature, remaining capacity and minimum internal resistance for discharge.

[0194] In a possible implementation, the first determining module 14 is specifically configured to:

[0195] determining eight maximum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the first corresponding relationship, and the third corresponding relationship;

[0196] determining eight minimum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the second corresponding relationship, and the fourth corresponding relationship;

[0197] The difference between the maximum value of the eight maximum internal resistances and the minimum value of the eight minimum internal resistances is determined as the maximum internal resistance difference.

[0198] In a possible implementation manner, the second determining module 15 is specifically configured to:

[0199] Determining the internal resistance range of the battery system according to the maximum internal resistance difference, the number of the single cells, the number of the single cells connected in series, and the number of the single cells connected in parallel;

[0200] The dynamic voltage difference of the battery system is determined according to the internal resistance extreme difference and the test current.

[0201] In a possible implementation manner, the second determining module 15 is specifically configured to:

[0202] If the number of the single cells is the same as the number of the single cells connected in series, the maximum internal resistance difference is determined as the internal resistance range;

[0203] If the number of single cells and the number of single cells connected in series are different, the internal resistance range Rpcak=Rcell / Ncell*Npack / N is determined, where Rpcak is the internal resistance range, Rcell is the maximum internal resistance difference, Ncell is the number of single cells, Npack is the number of single cells connected in series, and N is the number of single cells connected in parallel.

[0204] The pressure difference determination device for the battery system provided in the embodiment of the present application can implement the technical solution shown in the above method embodiment. Its implementation principle and beneficial effects are similar and will not be repeated here.

[0205] Figure 6 This is a schematic diagram of a device for determining a pressure difference in a battery system according to an embodiment of the present application. Figure 6 The battery system voltage difference determination device 20 may include: a memory 21 and a processor 22. Exemplarily, the memory 21 and the processor 22 are interconnected via a bus 23.

[0206] The memory 21 is used to store program instructions;

[0207] The processor 22 is configured to execute the program instructions stored in the memory, so as to enable the battery system pressure difference determination device 20 to execute the method shown in the above method embodiment.

[0208] An embodiment of the present application provides a computer-readable storage medium, wherein the computer-readable storage medium stores computer-executable instructions, which are used to implement the above method when executed by a processor.

[0209] The embodiment of the present application may also provide a computer program product, including a computer program, which can implement the above method when executed by a processor.

[0210] All or part of the steps of the above-mentioned method embodiments can be completed by hardware related to program instructions. The aforementioned program can be stored in a readable memory. When the program is executed, it performs the steps of the above-mentioned method embodiments; and the aforementioned memory (storage medium) includes: read-only memory (ROM), RAM, flash memory, hard disk, solid-state drive, magnetic tape, floppy disk, optical disc, and any combination thereof.

[0211] The embodiments of the present application are described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processing unit of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processing unit of the computer or other programmable data processing device generate instructions for implementing the steps in the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0212] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0213] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0214] Obviously, those skilled in the art may make various changes and modifications to the embodiments of the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations.

[0215] In this application, the term "include" and its variations may refer to non-restrictive inclusion; the term "or" and its variations may refer to "and / or". In this application, the terms "first", "second", etc. are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In this application, "plurality" refers to two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the previous and subsequent associated objects are in an "or" relationship.

Claims

1. A method for determining a pressure difference in a battery system, characterized in that: include: Obtain the number of single cells, the number of single cells in series, and the number of single cells in parallel in the battery system; Obtaining the maximum remaining power, minimum remaining power, maximum temperature, and minimum temperature of the battery system; Obtain the corresponding relationship between temperature, remaining power and internal resistance; determining, according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, and the corresponding relationship, a maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining powers; Determining a dynamic voltage difference of the battery system according to the maximum internal resistance difference, the number of the single cells, the number of the single cells connected in series, the number of the single cells connected in parallel, and a test current; Determining the dynamic voltage difference of the battery system according to the maximum internal resistance difference, the number of the single cells, the number of the single cells connected in series, the number of the single cells connected in parallel, and the test current includes: If the number of the single cells is the same as the number of the single cells connected in series, the maximum internal resistance difference is determined as the internal resistance range; If the number of single cells and the number of single cells connected in series are different, the internal resistance range Rpcak=Rcell / Ncell*Npack / N is determined, where Rpcak is the internal resistance range, Rcell is the maximum internal resistance difference, Ncell is the number of single cells, Npack is the number of single cells connected in series, and N is the number of single cells connected in parallel; The dynamic voltage difference of the battery system is determined according to the internal resistance extreme difference and the test current.

2. The method according to claim 1, characterized in that Obtaining the maximum remaining power and the minimum remaining power of the battery system, including: Obtaining a time difference between a current moment and a production moment of a single battery in the battery system; Obtain the maximum and minimum self-discharge rates of a single battery per unit time; determining a minimum remaining capacity of the battery system according to the time difference and the maximum self-discharge rate; The maximum remaining capacity of the battery system is determined according to the time difference and the minimum self-discharge rate.

3. The method according to claim 2, characterized in that Get the maximum and minimum self-discharge rates of a single battery per unit time, including: Obtaining M average self-discharge rates of a plurality of M sample single cells within a plurality of historical unit time periods, where M is an integer greater than 1; A maximum value among the M average self-discharge rates is determined as the maximum self-discharge rate, and a minimum value among the M average self-discharge rates is determined as the minimum self-discharge rate.

4. The method according to any one of claims 1 to 3, characterized in that The corresponding relationship includes: The first correspondence between temperature, remaining power and maximum internal resistance of charging; A second correspondence between temperature, remaining capacity, and minimum internal resistance for charging; The third correspondence between temperature, remaining capacity and maximum internal resistance of discharge; The fourth correspondence between temperature, remaining capacity and minimum internal resistance for discharge.

5. The method according to claim 4, characterized in that Determining, according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, and the corresponding relationship, a maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining powers, includes: determining eight maximum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the first corresponding relationship, and the third corresponding relationship; determining eight minimum internal resistances according to the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, the second corresponding relationship, and the fourth corresponding relationship; The difference between the maximum value of the eight maximum internal resistances and the minimum value of the eight minimum internal resistances is determined as the maximum internal resistance difference.

6. A device for determining a pressure difference in a battery system, characterized in that: The device comprises: The first acquisition module is used to obtain the number of single cells, the number of single cells connected in series, and the number of single cells connected in parallel in the battery system; A second acquisition module is used to obtain the maximum remaining power, minimum remaining power, maximum temperature and minimum temperature of the battery system; The third acquisition module is used to obtain the corresponding relationship between temperature, remaining power and internal resistance; a first determining module, configured to determine, based on the maximum remaining power, the minimum remaining power, the maximum temperature, the minimum temperature, and the corresponding relationship, a maximum internal resistance difference of the internal resistance of the battery system at different temperatures and different remaining powers; a second determination module, configured to determine a dynamic pressure difference of the battery system according to the maximum internal resistance difference, the number of the single cells, the number of the single cells connected in series, the number of the single cells connected in parallel, and a test current; The second determination module is further configured to determine the maximum internal resistance difference as the internal resistance range if the number of single cells is the same as the number of single cells connected in series; and to determine the internal resistance range Rpcak = Rcell / Ncell*Npack / N if the number of single cells is different from the number of single cells connected in series, wherein Rpcak is the internal resistance range, Rcell is the maximum internal resistance difference, Ncell is the number of single cells, Npack is the number of single cells connected in series, and N is the number of single cells connected in parallel; and determine the dynamic pressure difference of the battery system based on the internal resistance range and the test current.

7. A device for determining a pressure difference in a battery system, characterized in that: include: at least one processor; as well as a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method according to any one of claims 1 to 5.

8. A non-transitory computer-readable storage medium storing computer instructions, characterized in that: in, The computer instructions are used to cause the computer to execute the method according to any one of claims 1 to 5.

9. A computer program product, comprising a computer program, wherein when the computer program is executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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