Cell capacity grading method and device, cell capacity grading equipment and storage medium

Abstract

The invention discloses a battery cell capacity grading method and device, battery cell capacity grading equipment and a storage medium. The battery cell capacity grading method comprises the following steps: acquiring an actual environment temperature and a theoretical charging and discharging current of an environment where a battery cell in a battery module is located, and determining an actual charging and discharging current corresponding to the battery cell according to the actual environment temperature and the theoretical charging and discharging current; obtaining a first open-circuit voltage and a first internal resistance corresponding to the battery cell after the charging operation is completed, and a second open-circuit voltage and a second internal resistance corresponding to the battery cell after the discharging operation is completed after the charging operation is completed; and according to the first open-circuit voltage, the first internal resistance, the second open-circuit voltage and the second internal resistance, determining the actual self-discharge rate of the battery cell, and according to the actual self-discharge rate, completing the capacity grading of the battery cell of the battery module. According to the invention, the battery cells are stabilized, the consistency of the battery cells is improved, and the accuracy of the capacity grading process is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery cells, and in particular to a method and device for dividing battery cell capacity, a battery cell capacity dividing device, and a storage medium. Background Art

[0002] Cell capacity grading is a key process in lithium battery manufacturing. Cell capacity grading is the process of measuring and grading the actual capacity, internal resistance and other parameters of the battery cells through standardized charge and discharge tests. It mainly solves the performance discreteness problem caused by manufacturing differences in the same batch of battery cells. The batteries after capacity grading can be classified and grouped to ensure the consistency of the single cells in the battery pack.

[0003] The most common current charging and discharging methods are constant current and constant voltage. Constant current charging is charging the battery cell with a fixed current. This method does not take into account the effect of temperature on the battery cell, or assumes that the battery cell temperature remains unchanged during constant current charging. However, in reality, even if the battery cell capacity grading equipment has the function of controlling temperature, different battery cells in the battery cell capacity grading equipment will still have slight temperature differences due to slight differences in material density, electrolyte concentration, etc., resulting in slight changes in their respective C values. On the other hand, the most common screening method is the K value method, which refers to the ratio of the voltage difference between two moments to the time, representing the self-discharge index of the battery cell. Battery cells with qualified and consistent self-discharge are usually divided into the same group, but battery cells with the same self-discharge rate may still have different internal resistances, and the key parameters of the battery cell need to be comprehensively considered. Summary of the Invention

[0004] The present invention provides a battery cell capacity sizing method, device, battery cell capacity sizing equipment and storage medium to solve the problems in the current battery cell capacity sizing, such as inconsistent battery cell temperatures during the charging and discharging process affecting battery cell consistency, and the battery cell screening process failing to consider the influence of internal resistance, thereby leading to inaccurate battery cell screening.

[0005] According to one aspect of the present invention, a method for cell capacity division is provided, the method comprising:

[0006] Obtain the actual ambient temperature and theoretical charge and discharge current of the environment where the battery cells in the battery module are located, and determine the actual charge and discharge current corresponding to the battery cells based on the actual ambient temperature and the theoretical charge and discharge current;

[0007] After the battery cell completes the charge and discharge operation with the actual charge and discharge current, obtaining a first open circuit voltage and a first internal resistance corresponding to the battery cell after the charge operation is completed, and a second open circuit voltage and a second internal resistance corresponding to the battery cell after the discharge operation is completed;

[0008] The actual self-discharge rate of the battery cell is determined according to the first open circuit voltage, the first internal resistance, the second open circuit voltage and the second internal resistance, and the battery cell capacity of the battery module is divided according to the actual self-discharge rate.

[0009] Optionally, the actual charge and discharge current corresponding to the battery cell is determined based on the actual ambient temperature and the theoretical charge and discharge current, including:

[0010] The actual charge and discharge current corresponding to the battery cell is determined based on the following formula:

[0011] I=I0-α(T-T0)

[0012] Among them, I is the actual charge and discharge current; T is the actual ambient temperature; T0 is the preset charge and discharge temperature; I0 is the theoretical charge and discharge current; α is the temperature compensation coefficient.

[0013] Optionally, determining the actual self-discharge rate of the battery cell according to the first open circuit voltage, the first internal resistance, the second open circuit voltage, and the second internal resistance includes:

[0014] Determine a first self-discharge rate corresponding to the battery cell according to the first open-circuit voltage and the second open-circuit voltage, and determine a second self-discharge rate corresponding to the battery cell according to the first internal resistance and the second internal resistance;

[0015] An actual self-discharge rate of the battery cell is determined according to the first self-discharge rate and the second self-discharge rate.

[0016] Optionally, before determining the first self-discharge rate corresponding to the battery cell according to the first open-circuit voltage and the second open-circuit voltage, the method further includes:

[0017] Obtain the measured time length between the completion of the charging operation and the completion of the discharging operation of the battery cell;

[0018] Determining a first self-discharge rate corresponding to the battery cell according to the first open circuit voltage and the second open circuit voltage includes:

[0019] The first self-discharge rate corresponding to the battery cell is determined based on the following formula:

[0020]

[0021] Wherein, S1 is the first self-discharge rate; U1 is the first open circuit voltage; U2 is the second open circuit voltage; Δt is the measurement time length.

[0022] Optionally, determining a second self-discharge rate corresponding to the battery cell according to the first internal resistance and the second internal resistance includes:

[0023] The second self-discharge rate corresponding to the battery cell is determined based on the following formula:

[0024]

[0025] Wherein, S2 is the second self-discharge rate; R1 is the first open circuit voltage; and R2 is the second open circuit voltage.

[0026] Optionally, determining the actual self-discharge rate of the battery cell according to the first self-discharge rate and the second self-discharge rate includes:

[0027] The actual self-discharge rate of the battery cell is determined based on the following formula:

[0028] S=w1S1+w2S2

[0029] Wherein, S is the actual self-discharge rate; S1 is the first self-discharge rate; S2 is the second self-discharge rate; w1 is the first weight coefficient; w2 is the second weight coefficient.

[0030] Optionally, the cell capacity division method further includes:

[0031] Obtain the actual self-discharge rate corresponding to each battery cell in the battery module, and determine whether the battery cells in the battery module are consistent based on the actual self-discharge rate corresponding to each battery cell.

[0032] According to another aspect of the present invention, a battery cell capacity division device is provided, the battery cell capacity division device comprising:

[0033] The actual charge and discharge current determination module is used to obtain the actual ambient temperature and theoretical charge and discharge current of the environment where the battery cells in the battery module are located, and determine the actual charge and discharge current corresponding to the battery cells based on the actual ambient temperature and the theoretical charge and discharge current;

[0034] An internal resistance acquisition module is used to execute, after the battery cell completes the charge and discharge operation with the actual charge and discharge current, acquiring a first open circuit voltage and a first internal resistance corresponding to the battery cell after the charge operation is completed, and a second open circuit voltage and a second internal resistance corresponding to the battery cell after the discharge operation is completed;

[0035] The cell capacity division module is used to determine the actual self-discharge rate of the cell according to the first open circuit voltage, the first internal resistance, the second open circuit voltage and the second internal resistance, and complete the cell capacity division of the battery module according to the actual self-discharge rate.

[0036] According to another aspect of the present invention, a battery cell capacity division device is provided, the battery cell capacity division device comprising:

[0037] at least one processor; and,

[0038] a memory communicatively connected to at least one processor; wherein,

[0039] The memory stores a computer program that can be executed by at least one processor. The computer program is executed by the at least one processor so that the at least one processor can execute the battery cell capacity division method of any embodiment of the present invention.

[0040] According to another aspect of the present invention, a computer-readable storage medium is provided. The computer-readable storage medium stores computer instructions, which are used to enable a processor to implement the battery cell capacity division method according to any embodiment of the present invention when executed.

[0041] The technical solution of the embodiment of the present invention obtains the actual ambient temperature and theoretical charge and discharge current of the environment in which the battery cells in the battery module are located, and determines the actual charge and discharge current corresponding to the battery cells based on the actual ambient temperature and the theoretical charge and discharge current, taking the temperature factor into consideration, thereby reducing the heat generated by the battery cells during the charge and discharge process and improving the consistency of the battery cells after charge and discharge; after the battery cells complete the charge and discharge operations with the actual charge and discharge current, the first open circuit voltage and the first internal resistance corresponding to the battery cells after the charge operation are obtained, as well as the second open circuit voltage and the second internal resistance corresponding to the battery cells after the discharge operation are obtained, so as to comprehensively consider the changes in internal resistance and voltage, more comprehensively characterize the battery cell characteristics, and improve the ability to screen the battery cells; further, the actual self-discharge rate of the battery cells is determined based on the first open circuit voltage, the first internal resistance, the second open circuit voltage and the second internal resistance, and the battery cell capacity division of the battery module is completed based on the actual self-discharge rate, so as to achieve stable battery cells, improve battery cell consistency, and further improve the accuracy of the capacity division process.

[0042] It should be understood that the content described in this section is not intended to identify the key or important features of the embodiments of the present invention, nor is it intended to limit the scope of the present invention. Other features of the present invention will become readily understood through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0044] Figure 1 1 is a flow chart of a method for cell capacity division according to an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of a flow chart showing a charge and discharge operation of a battery cell using actual charge and discharge current according to an embodiment of the present invention;

[0046] Figure 3 2 is a schematic structural diagram of a battery cell capacity division device provided in an embodiment of the present invention;

[0047] Figure 4 This is a structural diagram of placing a battery cell into a static cabinet according to an embodiment of the present invention;

[0048] Figure 51 is a flow chart of a method for cell capacity division according to an embodiment of the present invention;

[0049] Figure 6 2 is a schematic structural diagram of a battery cell capacity division device provided in accordance with an embodiment of the present invention;

[0050] Figure 7 It is a structural schematic diagram of a cell capacity division device for implementing the cell capacity division method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0051] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0052] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0053] Figure 1 A flow chart of a cell capacity division method is provided for an embodiment of the present invention. This embodiment is applicable to multiple charge and discharge processes of a battery module, any charge and discharge process, and any stage of the screening process. The cell capacity division method can be performed by a cell capacity division device, which can be implemented in the form of hardware and / or software. The cell capacity division device can be configured in a cell capacity division device. Figure 1 As shown, the cell capacity division method includes:

[0054] S110 , obtaining the actual ambient temperature and theoretical charge and discharge current of the environment where the battery cells in the battery module are located, and determining the actual charge and discharge current corresponding to the battery cells based on the actual ambient temperature and the theoretical charge and discharge current.

[0055] Among them, the battery module is a key intermediate component in the battery system. The battery module is assembled by multiple battery cells in series or parallel. In this embodiment, any battery cell in the battery module can be divided into different capacities.

[0056] The actual ambient temperature of the environment where the battery cell is located can be detected in real time by a temperature detection device such as a temperature sensor. This embodiment does not impose any limitation on the specific acquisition method.

[0057] The theoretical charge and discharge current can be selected and set according to the capacity and other properties of the battery cell. This embodiment does not impose any special restrictions on the specific value of the theoretical charge and discharge current. Optionally, the theoretical charge and discharge current can be the constant current charging or constant current discharging current in the industry, specifically: I0=NC, where N is the charge and discharge current coefficient, N can be 0.3, etc., C represents the charge and discharge capacity rate of the battery, and 1C represents the current intensity at which the battery can be fully discharged within one hour.

[0058] On the basis of the above, the actual charge and discharge current corresponding to the battery cell is determined according to the actual ambient temperature and the theoretical charge and discharge current. Specifically, the actual charge and discharge current corresponding to the battery cell is determined based on the following formula: I = I0-α(T-T0), where I is the actual charge and discharge current; T is the actual ambient temperature; T0 is the preset charge and discharge temperature, that is, the preset charge and discharge temperature of the battery cell when charged with the theoretical charge and discharge current I0; I0 is the theoretical charge and discharge current; α is the temperature compensation coefficient.

[0059] It should be noted that the actual charge and discharge current can be calculated by the above formula. The actual charge and discharge current can include the actual charging current and the actual discharging current. Then the actual charging current and the actual discharging current can both be calculated by the above formula, and the actual charging current and the actual discharging current can be exactly the same value or different values. This embodiment does not impose any restrictions on this.

[0060] For example, taking the preset charge and discharge temperature as 45°C and the theoretical charge and discharge current as 1A, considering that the actual ambient temperature is 45.3°C due to slight differences in the process of the battery cell, and the temperature compensation coefficient α is set to 0.05, the actual charge and discharge current corresponding to the battery cell is:

[0061] I=I0-α(T-T0)=1-0.05*(45.3-45)=0.985A

[0062] It can be seen that after adding temperature compensation in this embodiment, when the actual ambient temperature is greater than the preset charge and discharge temperature, the charge and discharge current can be appropriately reduced. According to Joule's law: Q = I 2Rt, where Q represents the heat generated, I represents the current, R represents the resistance, and t represents the time. In this embodiment, the higher temperature cells will generate less heat due to the temperature compensation algorithm, thereby achieving a balance effect so that the temperatures between the cells remain dynamically consistent.

[0063] S120. After the battery cell completes the charge and discharge operation with the actual charge and discharge current, obtain a first open circuit voltage and a first internal resistance corresponding to the battery cell after the charge operation is completed, and a second open circuit voltage and a second internal resistance corresponding to the battery cell after the discharge operation is completed.

[0064] Specifically, the battery cell completes the charge and discharge operation with the actual charge and discharge current. Figure 2 As shown, the battery cell can be charged and discharged by the charging and discharging equipment, that is, see Figure 3 The poles of the battery cell shown are connected to the charging and discharging pins of the charging and discharging equipment, and charging and discharging are performed through the charging and discharging pins. Figure 2 As shown, the battery cells can be first charged with a constant current at the actual charge and discharge current. After reaching a certain voltage, constant voltage charging is adopted and maintained. As can be seen, in the process of cell capacity division in this embodiment, all battery cells in the battery module can be charged with a constant current before entering the next step of the static process.

[0065] Furthermore, in the next step of the rest process, the battery cells can be placed in a rest cabinet to allow sufficient time for the internal reaction of the battery cells and ultimately maintain stability. After a period of rest, the first open-circuit voltage and first internal resistance of the battery cells corresponding to the completion of the charging operation are measured. The rest period can be 24 hours or 48 hours, which is not limited in this embodiment.

[0066] The first open circuit voltage and the first internal resistance are measured in real time after the battery cell completes the charging operation. The first open circuit voltage and the first internal resistance can be measured by an existing measuring instrument, and this embodiment does not impose any limitation on this measurement method.

[0067] Continue to see Figure 2 As shown, the battery cell is discharged at a constant current or constant voltage with the actual charge and discharge current. After the discharge operation of the battery cell is completed, the battery cell can be placed in a static cabinet to enter the next step of the static process, wherein, see Figure 4 The static cabinet shown needs to ensure that the internal temperature remains stable, and after standing for a period of time, measure the second open circuit voltage and second internal resistance corresponding to the battery cell after the discharge operation is completed. Similarly, the length of the static time can be 24h or 48h, and this embodiment does not impose any restrictions on this.

[0068] The second open circuit voltage and the second internal resistance are measured in real time after the battery cell completes the discharge operation. The second open circuit voltage and the second internal resistance can be measured by an existing measuring instrument, and this embodiment does not impose any limitation on this measurement method.

[0069] Knowable, after Figure 2 The cells shown in the figure complete the charge and discharge operation with the actual charge and discharge current, which can screen out the cells with poor quality and cells with similar consistency, making subsequent work easier. Figure 2 The above steps shown in the figure, or after a certain process is completed, a certain step is performed separately. For example, constant current charging can be performed again after constant current discharge as needed, and such operation does not affect the subsequent execution effect.

[0070] S130 , determining an actual self-discharge rate of the battery cell according to the first open-circuit voltage, the first internal resistance, the second open-circuit voltage, and the second internal resistance, and completing battery cell capacity division of the battery module according to the actual self-discharge rate.

[0071] In this embodiment, the measured time length between the completion of the charging operation and the completion of the discharging operation of the battery cell is obtained, and then the first self-discharge rate corresponding to the battery cell is determined according to the measured time length, the first open-circuit voltage, and the second open-circuit voltage. Specifically, the first self-discharge rate corresponding to the battery cell is determined based on the following formula: Wherein, S1 is the first self-discharge rate; U1 is the first open circuit voltage; U2 is the second open circuit voltage; Δt is the measurement time length.

[0072] The measurement time length Δt is the time difference between the two measurements of the open circuit voltage and the internal resistance after the charging operation and the discharging operation are completed. It can be measured by a timer or other device and is not particularly limited in this embodiment.

[0073] Furthermore, the second self-discharge rate corresponding to the battery cell is determined according to the first internal resistance and the second internal resistance, that is, the second self-discharge rate corresponding to the battery cell is determined based on the following formula, specifically: Wherein, S2 is the second self-discharge rate; R1 is the first open circuit voltage; and R2 is the second open circuit voltage.

[0074] The actual self-discharge rate of the battery cell is determined according to the first self-discharge rate and the second self-discharge rate, that is, the actual self-discharge rate of the battery cell is determined based on the following formula: S=w1S1+w2S2, wherein S is the actual self-discharge rate; S1 is the first self-discharge rate; S2 is the second self-discharge rate; w1 is the first weight coefficient; and w2 is the second weight coefficient.

[0075] The first weight coefficient and the second weight coefficient can be selected and set according to the cell capacity requirements, and this embodiment does not impose any special restrictions on their specific values.

[0076] On the basis of the above, considering the actual multiple charge and discharge situations, if the charge and discharge times increase, the N value can be increased accordingly, and the actual self-discharge rate of the battery cell can be determined as follows: In this embodiment, by comprehensively considering the changes in open-circuit voltage and internal resistance, the consistency of the battery cells can be judged more comprehensively. The actual self-discharge rate of the battery cell needs to be within a certain range before the battery cell is considered qualified. For example, when the actual self-discharge rate S values ​​of two battery cells are close, it can be considered that the performance of the two battery cells is close.

[0077] For example, two cells in the battery module are connected Figure 2 In the charge and discharge operation shown, the front and rear voltages of cell 1 are 3V and 2V, respectively, and the internal resistances are 10mΩ and 12mΩ, respectively. The front and rear voltages of cell 2 are 3.05V and 2V, respectively, and the internal resistances are 9mΩ and 20mΩ, respectively. The duration is 1 unit. Furthermore, it can be obtained that the first self-discharge rate corresponding to cell 1 is 1, and the first self-discharge rate corresponding to cell 2 is 1.05, so the performance of the two cells is considered to be similar. Furthermore, assuming w1 = 0.6 and w2 = 0.4, specifically, the actual self-discharge rate corresponding to cell 1 is: The actual self-discharge rate corresponding to cell 2 is:

[0078] As can be seen, the numerical difference between the results of the two algorithms is quite large, which shows that the patented algorithm can more comprehensively characterize the characteristics of different battery cells. In summary, through temperature compensation, the battery cell charging and discharging algorithm is optimized, the heat generated by the battery cell during the charging and discharging process is reduced, and the consistency of the battery cell after charging and discharging is improved. By assigning weights to voltage and internal resistance changes, the battery cell screening algorithm is optimized, the battery cell characteristics are more comprehensively characterized, and the screening ability of batteries with excessive voltage drop and excessive internal resistance changes is improved.

[0079] On the basis of the above embodiment, the actual self-discharge rate corresponding to each battery cell in the battery module is obtained, and whether the battery cells in the battery module are consistent is determined according to the actual self-discharge rate corresponding to each battery cell.

[0080] The technical solution of the embodiment of the present invention obtains the actual ambient temperature and theoretical charge and discharge current of the environment where the battery cells in the battery module are located, and determines the actual charge and discharge current corresponding to the battery cells based on the actual ambient temperature and the theoretical charge and discharge current; after the battery cells complete the charge and discharge operation with the actual charge and discharge current, obtains the first open circuit voltage and first internal resistance corresponding to the battery cells after the charging operation is completed, as well as the second open circuit voltage and second internal resistance corresponding to the battery cells after the discharge operation is completed; determines the actual self-discharge rate of the battery cells based on the first open circuit voltage, the first internal resistance, the second open circuit voltage and the second internal resistance, and completes the cell capacity division of the battery module based on the actual self-discharge rate. The present invention solves the current problem that inconsistent cell temperature during the charge and discharge process in cell capacity division affects cell consistency, and that the cell screening process does not consider the influence of internal resistance, thereby leading to inaccurate cell screening, thereby achieving stable cell performance, improving cell consistency, and further improving the accuracy of the capacity division process.

[0081] Based on the same inventive concept, Figure 5 This is a flow chart of a cell capacity division method provided by an embodiment of the present invention. This embodiment provides an optional implementation method based on the above embodiment. Figure 5 As shown, the cell capacity division method includes:

[0082] S210 , obtaining the actual ambient temperature and theoretical charge and discharge current of the environment where the battery cells in the battery module are located, and determining the actual charge and discharge current corresponding to the battery cells according to the actual ambient temperature and the theoretical charge and discharge current.

[0083] Specifically, the actual charge and discharge current corresponding to the battery cell is determined based on the following formula:

[0084] I=I0-α(T-T0)

[0085] Among them, I is the actual charge and discharge current; T is the actual ambient temperature; T0 is the preset charge and discharge temperature; I0 is the theoretical charge and discharge current; α is the temperature compensation coefficient.

[0086] S220. After the battery cell completes the charge and discharge operation with the actual charge and discharge current, obtain a first open circuit voltage and a first internal resistance corresponding to the battery cell after the charge operation is completed, and a second open circuit voltage and a second internal resistance corresponding to the battery cell after the discharge operation is completed.

[0087] S230: Obtain the measured time length between the completion of the charging operation and the completion of the discharging operation of the battery cell.

[0088] S240 , determining a first self-discharge rate corresponding to the battery cell according to the measurement time length, the first open-circuit voltage, and the second open-circuit voltage, and determining a second self-discharge rate corresponding to the battery cell according to the first internal resistance and the second internal resistance.

[0089] Specifically, the first self-discharge rate corresponding to the battery cell is determined based on the following formula:

[0090]

[0091] Wherein, S1 is the first self-discharge rate; U1 is the first open circuit voltage; U2 is the second open circuit voltage; Δt is the measurement time length.

[0092] Furthermore, the second self-discharge rate corresponding to the battery cell is determined based on the following formula, specifically:

[0093]

[0094] Wherein, S2 is the second self-discharge rate; R1 is the first open circuit voltage; and R2 is the second open circuit voltage.

[0095] S250: Determine the actual self-discharge rate of the battery cell according to the first self-discharge rate and the second self-discharge rate.

[0096] Specifically, the actual self-discharge rate of the battery cell is determined based on the following formula:

[0097] S=w1S1+w2S2

[0098] Wherein, S is the actual self-discharge rate; S1 is the first self-discharge rate; S2 is the second self-discharge rate; w1 is the first weight coefficient; w2 is the second weight coefficient.

[0099] S260: Complete the cell capacity division of the battery module according to the actual self-discharge rate.

[0100] S270: Obtain an actual self-discharge rate corresponding to each battery cell in the battery module, and determine whether the battery cells in the battery module are consistent based on the actual self-discharge rates corresponding to each battery cell.

[0101] The technical solution of the embodiment of the present invention, by optimizing the battery cell charging and discharging algorithm and taking temperature factors into consideration, reduces the heat generated by the battery cell during the charging and discharging process and improves the consistency of the battery cell after charging and discharging; by optimizing the battery cell screening algorithm and comprehensively considering the changes in internal resistance and voltage, the battery cell characteristics are more comprehensively characterized and the battery cell screening capability is improved; it can be seen that the charging and discharging algorithm and the screening algorithm are applicable to multiple charging and discharging processes, any charging and discharging process, and any stage of the screening process, with flexibility and high applicability.

[0102] Based on the same inventive concept, Figure 6 This is a schematic diagram of the structure of a battery cell capacity division device provided by an embodiment of the present invention. Figure 6 As shown, the battery cell capacity division device includes:

[0103] The actual charge and discharge current determination module 310 is used to obtain the actual ambient temperature and theoretical charge and discharge current of the environment in which the battery cells in the battery module are located, and determine the actual charge and discharge current corresponding to the battery cells based on the actual ambient temperature and the theoretical charge and discharge current;

[0104] An internal resistance acquisition module 320 is configured to acquire, after the battery cell completes a charge and discharge operation with an actual charge and discharge current, a first open circuit voltage and a first internal resistance corresponding to the battery cell after the charge operation is completed, and a second open circuit voltage and a second internal resistance corresponding to the battery cell after the discharge operation is completed;

[0105] The cell capacity division module 330 is configured to determine the actual self-discharge rate of the cell according to the first open circuit voltage, the first internal resistance, the second open circuit voltage, and the second internal resistance, and to complete the cell capacity division of the battery module according to the actual self-discharge rate.

[0106] Optionally, the actual charge and discharge current corresponding to the battery cell is determined based on the actual ambient temperature and the theoretical charge and discharge current, specifically for:

[0107] The actual charge and discharge current corresponding to the battery cell is determined based on the following formula:

[0108] I=I0-α(T-T0)

[0109] Among them, I is the actual charge and discharge current; T is the actual ambient temperature; T0 is the preset charge and discharge temperature; I0 is the theoretical charge and discharge current; α is the temperature compensation coefficient.

[0110] Optionally, determining the actual self-discharge rate of the battery cell according to the first open circuit voltage, the first internal resistance, the second open circuit voltage, and the second internal resistance is specifically used for:

[0111] Determine a first self-discharge rate corresponding to the battery cell according to the first open-circuit voltage and the second open-circuit voltage, and determine a second self-discharge rate corresponding to the battery cell according to the first internal resistance and the second internal resistance;

[0112] An actual self-discharge rate of the battery cell is determined according to the first self-discharge rate and the second self-discharge rate.

[0113] Optionally, the cell capacity dividing device further includes:

[0114] A measurement time length acquisition module is used to obtain the measurement time length between the completion of the charging operation and the completion of the discharging operation of the battery cell;

[0115] Determining a first self-discharge rate corresponding to the battery cell according to the first open circuit voltage and the second open circuit voltage is specifically used for:

[0116] The first self-discharge rate corresponding to the battery cell is determined based on the following formula:

[0117]

[0118] Wherein, S1 is the first self-discharge rate; U1 is the first open circuit voltage; U2 is the second open circuit voltage; Δt is the measurement time length.

[0119] Optionally, determining a second self-discharge rate corresponding to the battery cell according to the first internal resistance and the second internal resistance is specifically used for:

[0120] The second self-discharge rate corresponding to the battery cell is determined based on the following formula:

[0121]

[0122] Wherein, S2 is the second self-discharge rate; R1 is the first open circuit voltage; and R2 is the second open circuit voltage.

[0123] Optionally, determining the actual self-discharge rate of the battery cell according to the first self-discharge rate and the second self-discharge rate is specifically used for:

[0124] The actual self-discharge rate of the battery cell is determined based on the following formula:

[0125] S=w1S1+w2S2

[0126] Wherein, S is the actual self-discharge rate; S1 is the first self-discharge rate; S2 is the second self-discharge rate; w1 is the first weight coefficient; w2 is the second weight coefficient.

[0127] Optionally, the cell capacity dividing device further includes:

[0128] The consistency judgment module is used to obtain the actual self-discharge rate corresponding to each battery cell in the battery module, and determine whether the battery cells in the battery module are consistent according to the actual self-discharge rate corresponding to each battery cell.

[0129] The battery cell capacity division device provided in the embodiment of the present invention can execute the battery cell capacity division method provided in any embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the battery cell capacity division method.

[0130] Based on the same inventive concept, Figure 7 FIG. 4 is a schematic diagram showing a structure of a cell capacity dividing device 410 that can be used to implement an embodiment of the present invention. Figure 7 As shown, the cell capacity division device 410 includes at least one processor 411, and a memory connected to the at least one processor 411, such as a read-only memory (ROM 412), a random access memory (RAM 413), etc., wherein the memory stores a computer program that can be executed by at least one processor, and the processor 411 can perform various appropriate actions and processes according to the computer program stored in the read-only memory (ROM 412) or the computer program loaded from the storage unit 418 to the random access memory (RAM 413). In RAM 413, various programs and data required for the operation of the cell capacity division device 410 can also be stored. The processor 411, ROM 412 and RAM 413 are connected to each other via a bus 414. An I / O (input / output) interface 415 is also connected to the bus 414.

[0131] Multiple components in the cell capacity division device 410 are connected to an I / O interface 415, including an input unit 416, such as a keyboard and mouse; an output unit 417, such as various types of displays and speakers; a storage unit 418, such as a magnetic disk and optical disk; and a communication unit 419, such as a network card, a modem, a wireless communication transceiver, etc. The communication unit 419 allows the cell capacity division device 410 to exchange information / data with other devices via a computer network such as the Internet and / or various telecommunication networks.

[0132] Processor 411 can be various general-purpose and / or specialized processing components with processing and computing capabilities. Some examples of processor 411 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various dedicated artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, a digital signal processor (DSP), and any appropriate processor, controller, microcontroller, etc. Processor 411 executes the various methods and processes described above, such as the cell capacity sizing method.

[0133] In some embodiments, the cell capacity sizing method may be implemented as a computer program, which is tangibly contained in a computer-readable storage medium, such as a storage unit 418. In some embodiments, part or all of the computer program may be loaded and / or installed on the cell capacity sizing device 410 via the ROM 412 and / or the communication unit 419. When the computer program is loaded into the RAM 413 and executed by the processor 411, one or more steps of the cell capacity sizing method described above may be performed. Alternatively, in other embodiments, the processor 411 may be configured to execute the cell capacity sizing method in any other appropriate manner (e.g., by means of firmware).

[0134] Various embodiments of the systems and techniques described herein can be implemented in digital electronic circuit systems, integrated circuit systems, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), system-on-chip systems (SOCs), programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments can include being implemented in one or more computer programs that are executable and / or interpreted on a programmable system that includes at least one programmable processor, which can be a special purpose or general purpose programmable processor that can receive data and instructions from a storage system, at least one input device, and at least one output device, and transmit data and instructions to the storage system, the at least one input device, and the at least one output device.

[0135] Computer programs for implementing the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when the computer program is executed by the processor, the functions / operations specified in the flowcharts and / or block diagrams are implemented. The computer program may be executed entirely on the machine, partially on the machine, as a stand-alone software package, partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0136] In the context of the present invention, computer-readable storage media can be tangible media that can contain or store a computer program for use with an instruction execution system, device or equipment or used in combination with an instruction execution system, device or equipment. Computer-readable storage media can include but are not limited to electronic, magnetic, optical, electromagnetic, infrared or semiconductor systems, devices or equipment, or any suitable combination of the foregoing. Alternatively, computer-readable storage media can be machine-readable signal media. More specific examples of machine-readable storage media can include electrical connections based on one or more lines, portable computer disks, hard disks, random access memories (RAM), read-only memories (ROM), erasable programmable read-only memories (EPROM or flash memory), optical fibers, portable compact disk read-only memories (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0137] To provide user interaction, the systems and techniques described herein can be implemented on a cell-storage device that has: a display device (e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor) for displaying information to the user; and a keyboard and pointing device (e.g., a mouse or trackball) through which the user can provide input to the cell-storage device. Other types of devices can also be used to provide user interaction; for example, the feedback provided to the user can be any form of sensory feedback (e.g., visual feedback, auditory feedback, or tactile feedback); and input from the user can be received in any form (including acoustic input, voice input, or tactile input).

[0138] The systems and techniques described herein can be implemented in a computing system that includes back-end components (e.g., as a data server), or a computing system that includes middleware components (e.g., an application server), or a computing system that includes front-end components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and techniques described herein), or a computing system that includes any combination of such back-end components, middleware components, or front-end components. The components of the system can be interconnected by any form or medium of digital data communication (e.g., a communication network). Examples of communication networks include: a local area network (LAN), a wide area network (WAN), a blockchain network, and the Internet.

[0139] A computing system may include clients and servers. The clients and servers are typically remote from each other and typically interact via a communication network. This client-server relationship arises through computer programs running on the respective computers, creating a client-server relationship. The server may be a cloud server, also known as a cloud computing server or cloud host. This server is a hosting product within the cloud computing service ecosystem that addresses the management difficulties and limited scalability of traditional physical hosting and VPS services.

[0140] It should be understood that the various forms of the processes shown above can be used to reorder, add, or delete steps. For example, the steps described in the present invention can be performed in parallel, sequentially, or in a different order, as long as the desired results of the technical solution of the present invention can be achieved. This is not limited herein.

[0141] The above specific embodiments do not limit the scope of protection of the present invention. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention are intended to be included within the scope of protection of the present invention.

Claims

1. A method for dividing the capacity of a battery cell, characterized in that: include: Obtaining the actual ambient temperature and theoretical charge and discharge current of the environment in which the battery cells in the battery module are located, and determining the actual charge and discharge current corresponding to the battery cells based on the actual ambient temperature and the theoretical charge and discharge current; After the battery cell completes a charge and discharge operation with the actual charge and discharge current, obtaining a first open circuit voltage and a first internal resistance corresponding to the battery cell after the charge operation is completed, and a second open circuit voltage and a second internal resistance corresponding to the battery cell after the discharge operation is completed; The actual self-discharge rate of the battery cell is determined according to the first open-circuit voltage, the first internal resistance, the second open-circuit voltage, and the second internal resistance, and the battery cell capacity division of the battery module is completed according to the actual self-discharge rate.

2. The battery cell capacity division method according to claim 1, wherein: Determining the actual charge and discharge current corresponding to the battery cell according to the actual ambient temperature and the theoretical charge and discharge current includes: The actual charge and discharge current corresponding to the battery cell is determined based on the following formula: I=I0-α(T-T0) Among them, I is the actual charge and discharge current; T is the actual ambient temperature; T0 is the preset charge and discharge temperature; I0 is the theoretical charge and discharge current; α is the temperature compensation coefficient.

3. The battery cell capacity division method according to claim 1, wherein: Determining an actual self-discharge rate of the battery cell according to the first open circuit voltage, the first internal resistance, the second open circuit voltage, and the second internal resistance includes: Determining a first self-discharge rate corresponding to the battery cell according to the first open-circuit voltage and the second open-circuit voltage, and determining a second self-discharge rate corresponding to the battery cell according to the first internal resistance and the second internal resistance; An actual self-discharge rate of the battery cell is determined according to the first self-discharge rate and the second self-discharge rate.

4. The battery cell capacity division method according to claim 3, characterized in that: Before determining a first self-discharge rate corresponding to the battery cell according to the first open-circuit voltage and the second open-circuit voltage, the method further includes: Obtaining a measured time length between the completion of the charging operation and the completion of the discharging operation of the battery cell; Determining a first self-discharge rate corresponding to the battery cell according to the first open circuit voltage and the second open circuit voltage includes: The first self-discharge rate corresponding to the battery cell is determined based on the following formula: Wherein, S1 is the first self-discharge rate; U1 is the first open-circuit voltage; U2 is the second open-circuit voltage; and Δt is the measurement time length.

5. The battery cell capacity division method according to claim 4, characterized in that: Determining a second self-discharge rate corresponding to the battery cell according to the first internal resistance and the second internal resistance includes: The second self-discharge rate corresponding to the battery cell is determined based on the following formula, specifically: Wherein, S2 is the second self-discharge rate; R1 is the first open-circuit voltage; and R2 is the second open-circuit voltage.

6. The battery cell capacity division method according to claim 3, characterized in that: Determining an actual self-discharge rate of the battery cell according to the first self-discharge rate and the second self-discharge rate includes: The actual self-discharge rate of the battery cell is determined based on the following formula: S=w1S1+w2S2 Wherein, S is the actual self-discharge rate; S1 is the first self-discharge rate; S2 is the second self-discharge rate; w1 is the first weight coefficient; and w2 is the second weight coefficient.

7. The battery cell capacity division method according to claim 1, characterized in that: The battery cell capacity division method further includes: An actual self-discharge rate corresponding to each of the battery cells in the battery module is obtained, and whether the battery cells in the battery module are consistent is determined according to the actual self-discharge rate corresponding to each of the battery cells.

8. A battery cell capacity division device, characterized in that: include: An actual charge and discharge current determination module is used to obtain the actual ambient temperature and theoretical charge and discharge current of the environment in which the battery cells in the battery module are located, and determine the actual charge and discharge current corresponding to the battery cells based on the actual ambient temperature and the theoretical charge and discharge current; an internal resistance acquisition module, configured to acquire, after the battery cell completes a charge and discharge operation with the actual charge and discharge current, a first open circuit voltage and a first internal resistance corresponding to the battery cell after the charge operation is completed, and a second open circuit voltage and a second internal resistance corresponding to the battery cell after the discharge operation is completed; A cell capacity division module is used to determine the actual self-discharge rate of the cell according to the first open circuit voltage, the first internal resistance, the second open circuit voltage and the second internal resistance, and complete the cell capacity division of the battery module according to the actual self-discharge rate.

9. A battery cell capacity separation device, characterized in that: The battery cell capacity division device comprises: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores a computer program that can be executed by the at least one processor, and the computer program is executed by the at least one processor so that the at least one processor can execute the battery cell capacity division method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a processor to implement the battery cell capacity division method according to any one of claims 1 to 7 when executed.

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