Charging Control Method, Device, Electronic Device and Storage Medium of Battery Pack

Abstract

The present application provides a charging control method, device, electronic device and storage medium for a battery pack. The battery pack includes at least two groups of batteries connected in parallel. The method includes: determining the state of charge corresponding to each battery respectively after a preset charging time based on charging parameters; calculating the amount of charge transfer between the batteries after stopping charging at the preset charging time according to the state of charge; judging whether the battery receiving charge is in a critical overcharge state according to the amount of charge transfer; if so, stopping charging the battery pack after the preset charging time. After the charging of the battery pack is completed, even if there is mutual charging between the batteries in the battery pack, the battery cells in each battery will not be overcharged after receiving charge, thereby prolonging the service life of the battery pack and reducing the probability of safety hazards occurring in the battery pack.

Description

Technical Field

[0001] The present application relates to the technical field of batteries, and in particular, to a charging control method, device, electronic device, and storage medium for a battery pack. Background Art

[0002] Energy conservation and emission reduction are the keys to the sustainable development of the automotive industry. Electric vehicles have become an important part of the sustainable development of the automotive industry due to their advantages of energy conservation and environmental protection. For electric vehicles, battery technology is an important factor related to their development.

[0003] After the battery pack is fully charged, there will be a problem of overcharging of battery cells in each battery branch, which will shorten the service life of the battery pack and pose a safety hazard. Summary of the Invention

[0004] In view of the above problems, the present application provides a charging control method, device, electronic device, and storage medium for a battery pack, which can avoid the problem of overcharging of battery cells in a battery pack with multiple parallel-connected batteries.

[0005] In a first aspect, the present application provides a charging control method for a battery pack. The battery pack includes at least two groups of parallel-connected batteries. The method includes: determining the state of charge corresponding to each battery after a preset charging time based on charging parameters; calculating the charge transfer amount between the batteries after stopping charging at the preset charging time according to the state of charge; determining whether the battery receiving the charge is in a critical overcharge state according to the charge transfer amount; if so, stopping charging the battery pack after the preset charging time.

[0006] In the technical solution of the embodiment of the present application, the charge transfer amount between the batteries in the battery pack after stopping charging at the preset charging time is calculated according to the state of charge corresponding to each battery in the battery pack after the preset charging time, so as to determine whether the battery receiving the charge is in a critical overcharge state according to the charge transfer amount. If so, charging the battery pack is stopped after the preset charging time. In this way, after the battery pack is fully charged, even if there is mutual charging between the batteries in the battery pack, the battery cells in each battery will not be overcharged after receiving the charge, thereby extending the service life of the battery pack and reducing the probability of safety hazards occurring in the battery pack.

[0007] In some embodiments, the state of charge is a set of the state of charge of each battery cell corresponding to each battery in the batteries; the calculating the amount of charge transfer between the batteries after stopping charging at the preset charging time according to the state of charge includes: determining the average state of charge corresponding to any two sets of batteries respectively according to the state of charge, where the any two sets of batteries are two sets of batteries having a charge transfer relationship; determining the average charge difference between the any two sets of batteries according to the average state of charge; and calculating the amount of charge transfer between the any two sets of batteries after stopping charging at the preset charging time based on the conversion relationship between the open circuit voltage and the state of charge, the average charge difference, and the average state of charge of the battery receiving charge in the any two sets of batteries.

[0008] By calculating the average charge difference between two sets of batteries through the average state of charge corresponding to the two sets of batteries, since there are often multiple battery cells in a battery and the state of charge of each battery cell will vary, therefore, the average state of charge can more truly represent the state of charge level of each battery cell in the battery, and further more accurately determine the amount of charge transfer between the two sets of batteries.

[0009] In some embodiments, the calculating the amount of charge transfer between the any two sets of batteries after stopping charging at the preset charging time based on the conversion relationship between the open circuit voltage and the state of charge, the average charge difference, and the average state of charge of the battery receiving charge in the any two sets of batteries includes: according to OCV(SOC avg +k·SOC trans )=OCV(SOC avg +ΔSOC-SOC trans ) calculating the amount of charge transfer between the any two sets of batteries after stopping charging at the preset charging time; where OCV() represents the conversion relationship between the open circuit voltage and the state of charge, SOC avg represents the average state of charge of the battery receiving charge, ΔSOC represents the average charge difference between the any two sets of batteries, k represents the battery aging coefficient, and SOC trans represents the amount of charge transfer between the any two sets of batteries.

[0010] In the process of calculating the amount of charge transfer between two batteries based on the conversion relationship between the open circuit voltage and the state of charge, the average charge difference between the two batteries, and the average state of charge of the battery receiving charge in the two batteries, the aging condition of the battery receiving charge, that is, the actual amount of charge that the battery receiving charge can receive, is fully considered. In the process of calculating the amount of charge transfer, adding the battery aging coefficient can more accurately determine the amount of charge transfer between the two batteries, and further more accurately determine whether the battery receiving charge will reach the critical overcharge state after stopping charging at the preset time, so as to more precisely control the charging of the battery pack.

[0011] In some embodiments, before calculating the charge transfer amount between any two sets of batteries after stopping charging at the preset charging time according to OCV(SOC avg +k·SOC trans )=OCV(SOC avg +ΔSOC - SOC trans ), the method further includes: obtaining the theoretical open - circuit voltage and the actual open - circuit voltage of the battery that receives charge after the last mutual charging of any two sets of batteries; determining whether the theoretical open - circuit voltage is equal to the actual open - circuit voltage; if so, using the battery aging coefficient used in the previous charging process as the battery aging coefficient; if not, determining the battery aging coefficient according to OCV(SOC avg +k·SOC trans计算 )=OCV(SOC avg +ΔSOC - SOC trans实际 ) or ; where OCV() represents the conversion relationship between the open - circuit voltage and the state of charge, SOC avg represents the average state of charge of the battery that receives charge, ΔSOC represents the average charge difference between any two sets of batteries, k represents the battery aging coefficient, SOC trans计算 represents the theoretical charge transfer amount between any two sets of batteries in the previous time, and SOC trans实际 represents the actual charge transfer amount between any two sets of batteries in the previous time.

[0012] During each charging control of the battery pack, it is necessary to correct the battery aging parameters so that the actual charge acquisition amount of the battery that receives charge can be accurately estimated during each charging control, and further, it can be more accurately determined whether the battery that receives charge will reach the critical over - charge state after stopping charging at the preset time, thereby more precisely controlling the charging of the battery pack.

[0013] In some embodiments, determining the average state of charge corresponding to any two sets of batteries according to the state of charge includes: obtaining the total open - circuit voltage corresponding to any two sets of batteries and the total number of battery cells; determining the average open - circuit voltage corresponding to any two sets of batteries according to the total open - circuit voltage and the total number; and determining the average state of charge of any two sets of batteries based on the average open - circuit voltage and the conversion relationship between the open - circuit voltage and the state of charge.

[0014] Obtain the open-circuit voltage of each battery cell, and add up the open-circuit voltages of each battery cell to obtain the total open-circuit voltage of the battery. Since there is a certain error every time an open-circuit voltage of a battery cell is obtained, and when adding up the open-circuit voltages of each battery cell, the total open-circuit voltage of the battery obtained will have a large error. By directly obtaining the total open-circuit voltage of the battery and determining the average open-circuit voltage of the battery based on the total open-circuit voltage of the battery, thereby determining the average state of charge of the battery, the error in obtaining the total open-circuit voltage of the battery can be reduced, and then the accuracy of determining the average state of charge of the battery can be improved. Furthermore, the amount of charge transfer can be determined more accurately, and then the accuracy of the charging control of the battery pack can be improved, and overcharging of the battery can be avoided more accurately.

[0015] In some embodiments, the determining whether the battery receiving charge is in a critical overcharge state according to the amount of charge transfer includes: in the battery receiving charge, determining a target battery cell with the highest state of charge before charge transfer; and judging whether the battery receiving charge is in a critical overcharge state according to the amount of charge transfer, the state of charge of the target battery cell, the conversion relationship between the open-circuit voltage and the state of charge, and the warning voltage value.

[0016] By determining whether overcharging will occur after the target battery cell with the highest state of charge before charge transfer in the battery receiving charge stops charging within a preset charging time, it can be determined whether overcharging will occur after the battery receiving charge stops charging within the preset charging time, which can reduce the calculation amount of the state of charge of the battery, and then improve the speed of determining whether the battery is in a critical overcharge state, thereby improving the real-time performance of the charging control of the battery pack.

[0017] In some embodiments, the judging whether the battery receiving charge is in a critical overcharge state according to the amount of charge transfer, the state of charge of the target battery cell, the conversion relationship between the open-circuit voltage and the state of charge, and the warning voltage value includes: if OCV(SOC avg +ΔSOC abn -k·SOC trans )≤V warning holds, it is determined that the battery receiving charge is not in a critical overcharge state; if OCV(SOC avg +ΔSOC abn -k·SOC trans )≤V warning does not hold, it is determined that the battery receiving charge is in a critical overcharge state; where OCV() represents the conversion relationship between the open-circuit voltage and the state of charge, SOC avg represents the average state of charge of the battery receiving charge, ΔSOC abn represents the difference between the state of charge of the target battery cell and SOC avg , k represents the battery aging coefficient, SOCtrans represents the amount of charge transfer between any two sets of batteries, where the any two sets of batteries are two sets of batteries having a charge transfer relationship, V warning represents the warning voltage value.

[0018] When determining the open-circuit voltage of the target battery cell with the highest pre-charge state before charge transfer in the battery receiving charge after charge transfer, during the process of charge transfer to the target battery cell, the battery aging parameter is still considered, that is, considering the actual amount of charge received by the target battery cell, the accuracy of determining the open-circuit voltage of the target battery cell after mutual charging can be improved, and further, it can be more accurately determined whether the battery receiving charge is in a critical overcharge state, thereby improving the accuracy of battery pack charging control.

[0019] In some embodiments, after determining whether the battery receiving charge is in a critical overcharge state according to the amount of charge transfer, the method further includes: if not, determining the state difference between the current charge state of the battery receiving charge and the critical overcharge state; when the state difference is greater than or equal to a preset difference, charging the battery pack at a first charging rate after the preset charging time; when the state difference is less than the preset difference, charging the battery pack at a second charging rate after the preset charging time, and the second charging rate is less than the first charging rate.

[0020] Determine the subsequent charging rate of the battery pack according to the size of the state difference between the current charge state of the battery receiving charge and the critical overcharge state. When the state difference is large, a higher charging rate can be used to continue charging the battery pack, which can shorten the charging time of the battery pack and improve the charging efficiency of the battery pack. When the state difference is small, a lower charging rate can be used to continue charging the battery pack, which can avoid the battery quickly passing through the critical overcharge state, and when the battery is about to reach the critical overcharge state, the charging can be accurately controlled to stop, improving the accuracy of charging control.

[0021] In a second aspect, the present application provides a charging control device for a battery pack, where the battery pack includes at least two sets of parallel-connected batteries, and the device includes: a determination module for determining the charge state corresponding to each battery respectively after a preset charging time based on charging parameters; a calculation module for calculating the amount of charge transfer between the batteries after stopping charging at the preset charging time according to the charge state; a judgment module for judging whether the battery receiving charge is in a critical overcharge state according to the amount of charge transfer; and a control module for, if so, stopping charging the battery pack after the preset charging time.

[0022] In a third aspect, the present application provides an electronic device, including: a processor, a memory, and a bus; wherein, the processor and the memory communicate with each other through the bus; and the processor is configured to call program instructions in the memory to execute the method in the first aspect.

[0023] In a fourth aspect, the present application provides a computer-readable storage medium, characterized by including: a stored program; wherein, when the program runs, it controls the device where the storage medium is located to execute the method in the first aspect.

[0024] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present application more obvious and understandable, the following specifically illustrates the specific implementation manners of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, in all the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0026] Figure 1 is a schematic structural diagram of a battery pack in an embodiment of the present application;

[0027] Figure 2 is a schematic flowchart of a charging control method for a battery pack in an embodiment of the present application;

[0028] Figure 3 is a schematic flowchart of determining the charge transfer amount in an embodiment of the present application;

[0029] Figure 4 is a schematic diagram of the correspondence between the open-circuit voltage and the state of charge in an embodiment of the present application Figure 1 ;

[0030] Figure 5 is a schematic diagram of the correspondence between the open-circuit voltage and the state of charge in an embodiment of the present application Figure 2 ;

[0031] Figure 6 is a schematic flowchart of determining whether the battery receiving charge is in a critical overcharge state in an embodiment of the present application;

[0032] Figure 7 is a schematic diagram of the state of charge of battery cells in each battery after mutual charging in an embodiment of the present application;

[0033] Figure 8It is a schematic flowchart of the further charging control process after determining that the battery is not in the critical overcharge state in the embodiments of the present application;

[0034] Figure 9 It is a schematic structure diagram of the charging control device of the battery pack in the embodiments of the present application Figure 1 ;

[0035] Figure 10 It is a schematic structure diagram of the charging control device of the battery pack in the embodiments of the present application Figure 2 ;

[0036] Figure 11 It is a schematic structure diagram of the electronic device in the embodiments of the present application. Detailed implementation manners

[0037] Next, embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0039] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity, specific order or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0040] Referring to "embodiment" herein means that a specific feature or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0041] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: there is A, there is both A and B, and there is B. In addition, the character " / " in this article generally means that the associated objects before and after are in an "or" relationship.

[0042] In the description of the embodiments of the present application, the term "plurality" means two or more (including two). Similarly, "multiple groups" means two or more groups (including two groups), and "multiple pieces" means two or more pieces (including two pieces).

[0043] In the description of the embodiments of the present application, the orientation or positional relationship indicated by technical terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the embodiments of the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the embodiments of the present application.

[0044] In the description of the embodiments of the present application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "coupling", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can also be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and can be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific circumstances.

[0045] Currently, with the continuous development of the electric vehicle industry, battery charging technology has gradually received more and more attention. For electric vehicles with high power consumption, such as electric bus vehicles, etc., due to their high power consumption characteristics, in order to be able to supply power to them continuously and stably, multiple batteries need to be connected in parallel to form a battery pack for use by electric vehicles.

[0046] The inventor noticed that after the battery pack has been used in multiple charge-discharge cycles, when the battery pack is charged again, after the charging is completed, mutual charging will still occur between the battery branches in the battery pack, that is, one battery branch charges another battery branch. The reason is that there is an impedance mismatch between the battery branches in the battery pack. Especially after the battery cells in each battery branch age, the degree of impedance mismatch between the battery branches becomes more obvious. After the battery pack finishes charging, there will be a situation where the overall state of charge (SOC) of one battery branch is higher than that of another battery branch. At this time, the battery branch with a high state of charge will charge the battery branch with a low state of charge, that is, backcharge, until the overall state of charge of the two battery branches is balanced. If the state of charge of a certain battery cell in the battery branch being charged is relatively high before the backcharge, then after the backcharge, the state of charge of this battery cell may exceed 100%, that is, overcharge. In this way, the service life of the battery pack is shortened, and in severe cases, safety hazards such as explosion and fire may be brought.

[0047] To avoid the problem of overcharging of the battery cells in each battery branch, the inventor found through research that the amount of charge transferred between the battery branches after stopping charging at each moment during the charging process of the battery pack can be calculated in sequence. Then, according to the calculation results of each time, it can be determined in sequence whether the state of charge of the battery cells in the battery branch being charged reaches its maximum state of charge after stopping charging the battery pack at each moment and after the backcharge between the battery branches in the battery pack is completed. If it does not reach, it means that stopping charging the battery pack at this time and having a backcharge between the battery branches will not cause overcharging of this battery cell, and at this time, the battery pack can continue to be charged. If it reaches, it means that stopping charging the battery pack at this time and having a backcharge between the battery branches will cause the state of charge of this battery cell to reach its maximum state of charge, and at this time, it is necessary to stop charging the battery pack. If the battery pack is still charged at this time, after stopping charging at a certain moment in the future and having a backcharge between the battery branches, the state of charge of this battery cell will exceed its maximum state of charge, resulting in overcharging of this battery cell. Therefore, at a certain moment, if it is judged that after stopping charging the battery pack at this time and having mutual charging between the battery branches, the state of charge of the battery cell with the highest charge state in the battery branch receiving the charge just reaches the maximum charge state it can accommodate, it can be determined to stop charging the battery pack.

[0048] By sequentially determining whether the state of charge of the battery cells in each battery branch reaches the maximum state of charge that it can accommodate after stopping charging at each moment during the charging process of the battery pack and after the backcharging of each battery branch is completed, and then determining whether to stop charging the battery pack at a certain moment according to the determination result. That is to say, during the process of controlling the charging of the battery pack, considering whether the state of charge of the battery cells in each battery branch exceeds the maximum state of charge that it can accommodate after mutual charging between the battery branches in the battery pack, so as to realize the control of the charging of the battery pack (that is, whether to stop charging). In this way, it is possible to avoid the problem of overcharging of the battery cells in each battery branch caused by the mutual charging between the battery branches in the battery pack after the charging of the battery pack is completed, thereby prolonging the service life of the battery pack and reducing the probability of safety hazards such as explosion and combustion of the battery pack.

[0049] The battery pack charging control method, device, electronic device and storage medium provided by the embodiments of the present application can be but are not limited to be used in power-consuming devices including a charging pack such as mobile phones, tablets, laptop computers, electric toys, electric tools, battery cars, electric vehicles, ships, spacecrafts, etc. Among them, the electric toys can include fixed or mobile electric toys. For example: game consoles, electric vehicle toys, electric ship toys, electric airplane toys, etc. The spacecraft can include airplanes, rockets, space shuttles, spaceships, etc. Through the battery pack charging control method, device, electronic device and storage medium provided by the embodiments of the present application, it is possible to avoid the problem of overcharging of the battery cells in the battery pack of the power-consuming device after the charging is completed, thereby prolonging the service life of the battery pack and reducing the safety hazards brought by overcharging of the battery pack.

[0050] The embodiments of the present application provide a battery pack charging control method, Figure 1 For the structural schematic diagram of the battery pack in the embodiments of the present application, see Figure 1 As shown, in the battery pack, there are at least two groups of parallel-connected batteries 101. And in each group of batteries 101, a plurality of battery cells 1011 are connected in series. Of course, in each group of batteries 101, there may also be only one battery cell 1011. The specific number of battery cells 1011 in each group of batteries 101 is not limited here. And the battery pack charging control method provided by the embodiments of the present application is used to Figure 1 charge and control the battery pack shown in

[0051] Figure 2 For the flowchart of the battery pack charging control method in the embodiments of the present application, see Figure 2 As shown, the method may include:

[0052] S21: Determine the state of charge corresponding to each battery after a preset charging time based on the charging parameters.

[0053] During the charging process of the battery pack, when charging stops at a certain moment, due to the impedance mismatch between the battery groups in the battery pack, there are differences in the open-circuit voltages of the battery groups at this moment. And the battery with a relatively higher open-circuit voltage will charge the battery with a relatively lower open-circuit voltage, that is, backcharging. And the backcharging process is actually a process of charge transfer. In order to avoid overcharging of the battery cells in the battery with a relatively lower open-circuit voltage after backcharging because they receive a charge amount exceeding their own tolerance, it is necessary to determine the state of charge corresponding to each battery after stopping charging the battery pack at this moment (i.e., the preset charging time) and before the batteries in the battery pack charge each other.

[0054] In order to determine the state of charge corresponding to each battery after the preset charging time, in the specific implementation process, it can be determined in the following two different time periods.

[0055] Time period 1: During the charging process of the battery pack.

[0056] That is to say, during the charging process of the battery pack, based on the charging parameters, the state of charge corresponding to each battery at the current moment is determined in real time.

[0057] Here, the charging parameters can be parameters measured in real time. Specifically, the charging parameters can refer to the open-circuit voltages currently corresponding to each battery group. Through the conversion relationship between the open-circuit voltage and the state of charge, the state of charge corresponding to each open-circuit voltage can be determined.

[0058] Of course, the charging parameters can also refer to the open-circuit voltages corresponding to each battery group before charging, the current flowing through each battery during the charging of the battery pack, and the current charging duration of the battery pack. Based on the current flowing through each battery and the current charging duration of the battery pack, by using ampere-hour integration, the charge amount obtained by each battery during the charging process can be obtained. And by converting the open-circuit voltage of each battery before charging into the state of charge, and then adding the state of charge of each battery before charging and the charge amount obtained during charging respectively, the open-circuit voltage currently corresponding to each battery can be obtained.

[0059] When there are multiple battery cells in a battery group, in order to obtain the state of charge of the battery, the open-circuit voltage of each battery cell can be obtained separately, or the total open-circuit voltage of all the battery cells in a group of battery cells can be directly obtained, and then the open-circuit voltage of the battery group can be obtained to obtain the state of charge of the battery group. The specific method for obtaining the open-circuit voltage of the battery is not limited here.

[0060] Time period 2: Before charging the battery pack.

[0061] That is to say, before charging the battery pack, based on the charging parameters, the state of charge corresponding to each battery at a certain moment is determined in advance.

[0062] Here, the charging parameters can be the charging power supply and related parameters of the battery. Specifically, the charging parameters can refer to the voltage of the charging power supply and the internal resistance of each battery. Through the voltage of the charging power supply and the internal resistance of each battery, the charging current of each battery can be obtained. Furthermore, through the charging current of each battery, the internal resistance of each battery, and the charging time, the state of charge of each battery can be obtained.

[0063] S22: Calculate the charge transfer amount between each battery after stopping charging at the preset charging time according to the state of charge.

[0064] Due to the impedance mismatch of each battery, after charging stops, the voltages of each battery will be different, and mutual charging will occur between each battery, that is, there will also be a transfer of charge between each battery. Therefore, after determining the state of charge corresponding to each battery after the preset charging time, the charge transfer amount between each battery after stopping charging at the preset charging time can be calculated.

[0065] Generally, charge flows from the battery with a relatively larger amount of charge to the battery with a relatively smaller amount of charge. Assume that the battery with a relatively larger amount of charge is the first branch, and the battery with a relatively smaller amount of charge is the second branch. First, the state of charge of the first branch can be subtracted from the state of charge of the second branch. Then, half of the result after subtraction is used as the charge transfer amount. In this way, the state of charge of the second branch plus the charge transfer amount is equal to the state of charge of the first branch minus the charge transfer amount in terms of the total charge amount, and thus there will no longer be charge transfer between the first branch and the second branch.

[0066] Of course, after determining the state of charge corresponding to each battery after the preset charging time, the charge transfer amount between each battery after stopping charging at the preset charging time can also be determined by other methods. For example: by solving equations. Still assume that the battery with a relatively larger amount of charge is the first branch, and the battery with a relatively smaller amount of charge is the second branch. First, the open-circuit voltage of the first branch after backcharging is represented by subtracting the charge transfer amount from the state of charge of the first branch on the left side of the equation. Then, the open-circuit voltage of the second branch after backcharging is represented by adding the charge transfer amount to the state of charge of the second branch on the right side of the equation. Finally, by solving the equation, the charge transfer amount between each battery after stopping charging at the preset charging time can also be obtained.

[0067] The above is described by taking the battery pack having two parallel-connected batteries, that is, two branches, as an example. When the battery pack has more than two parallel-connected batteries, that is, more than two branches, the charge transfer amount between each battery can also be determined by the above method, and finally, it is only necessary to balance the state of charge of each battery in the battery pack.

[0068] Assume that the battery pack has three parallel-connected batteries, namely the first branch, the second branch, and the third branch, and the state of charge of these three branches decreases in sequence after charging. Then, the charge transfer amount between any two branches (for example, the first branch and the second branch) can be determined first by the above method, and then the state of charge of the first branch and the second branch after transferring charges can be determined respectively. Then, the charge transfer amounts between the first branch and the third branch, and between the second branch and the third branch can be determined respectively by the above method. The sum of the charge transfer amounts obtained twice is the final required charge transfer amount between each battery.

[0069] Assume that the battery pack has four parallel-connected batteries, namely the first branch, the second branch, the third branch, and the fourth branch, and the state of charge of these four branches decreases in sequence after charging. In addition to determining the charge transfer amount in the manner of the above three branches, the charge transfer amounts between every two branches (for example, the first branch and the second branch, the third branch and the fourth branch) can be determined first by the above method for two branches, and then the state of charge of the first branch and the second branch after transferring charges, and the state of charge of the third branch and the fourth branch after transferring charges can be determined respectively. Then, the charge transfer amounts between the first and second branches and the third and fourth branches can be determined respectively by the above method for two branches. The sum of the charge transfer amounts obtained twice is the final required charge transfer amount between each battery.

[0070] S23: Judge whether the battery receiving the charge is in a critical overcharge state according to the charge transfer amount.

[0071] After determining the charge transfer amount transferred from one battery to another, if the charge transfer amount is too large, then the existing charge amount in the battery cell of the battery receiving the charge plus the transferred charge amount will exceed the maximum charge amount that the battery cell itself can accommodate, resulting in overcharging of the battery cell. Therefore, it is necessary to add the charge transfer amount to the existing charge amount in the battery receiving the charge, and judge whether the added charge amount reaches the maximum charge amount that the battery receiving the charge can accommodate, that is, judge whether the battery receiving the charge is in a critical overcharge state.

[0072] In the specific implementation process, the charge transfer amount needs to be added to each battery cell in the battery receiving the charge. Therefore, the charge transfer amount is averaged according to the number of battery cells in the battery receiving the charge, and then the averaged charge transfer amount is added to each battery cell in the battery receiving the charge respectively, so as to judge whether each battery cell is in a critical overcharge state after adding the charge.

[0073] S24: If so, stop charging the battery pack after the preset charging time.

[0074] If it is determined that the battery receiving the charge is in a critical overcharge state after adding the charge transfer amount, it indicates that after stopping charging the battery pack at the preset charging time, the batteries in the battery pack are charged with each other, and the batteries in the battery pack have reached the maximum bearing state. If they receive more charge, overcharging problems will occur. Then, the power supply can be controlled to stop charging the battery pack after the preset charging time.

[0075] If it is determined that the battery receiving the charge is not in a critical overcharge state after adding the charge transfer amount, it indicates that after stopping charging the battery pack at the preset charging time, even if the batteries in the battery pack are charged with each other, overcharging problems will not occur in the batteries in the battery pack. Then, the power supply can be controlled to continue charging the battery pack after the preset charging time.

[0076] That is to say, during the charging process of the battery pack, the charge transfer amount between each battery can be predicted in real time after stopping charging the battery pack at the current moment, and then it can be determined whether the battery receiving the charge is in a critical overcharge state, and further determine whether to stop charging the battery pack at the current moment, so as to ensure that after stopping charging, the mutual charging between each battery will not cause overcharging problems for the battery, thereby improving the service life of the battery.

[0077] Of course, it can also be before charging the battery pack, according to the charging duration, predict in turn the charge transfer amount between each battery after stopping charging the battery pack at each moment, and then determine whether the battery receiving the charge is in a critical overcharge state, and further determine whether to stop charging the battery pack at a certain moment, so as to ensure that after stopping charging, the mutual charging between each battery will not cause overcharging problems for the battery, thereby improving the service life of the battery.

[0078] As can be seen from the above, the charging control method of the battery pack provided by the embodiment of the present application calculates the charge transfer amount between each battery in the battery pack after stopping charging at the preset charging time according to the state of charge corresponding to each battery in the battery pack after the preset charging time, so as to judge whether the battery receiving the charge is in a critical overcharge state according to the charge transfer amount. If so, stop charging the battery pack after the preset charging time. In this way, after the charging of the battery pack is completed, even if there is mutual charging between the batteries in the battery pack, the battery cells in each battery will not have overcharging problems due to receiving charge, thereby extending the service life of the battery pack and reducing the probability of safety hazards occurring in the battery pack.

[0079] Based on the above embodiments, Figure 3 is a schematic flowchart for determining the charge transfer amount in the embodiment of the present application. Refer to Figure 3 As shown, when calculating the charge transfer amount between each battery after stopping charging at the preset charging time according to the state of charge, that is, in step S22, it may specifically include:

[0080] S221: Determine the average state of charge (SOC) corresponding to any two sets of batteries according to the state of charge.

[0081] Here, the state of charge is a set of the state of charge of each cell corresponding to each battery in the batteries. Any two sets of batteries are two sets of batteries having a charge transfer relationship.

[0082] That is to say, the state of charge of each cell of each battery in the battery pack is known. For any two sets of batteries having a charge transfer relationship, the average state of charge of all the cells in each set of batteries can be obtained through average value calculation.

[0083] S222: Determine the average charge difference between any two sets of batteries according to the average state of charge.

[0084] After determining the average state of charge corresponding to any two sets of batteries respectively, subtract the average state of charge corresponding to these two sets of batteries, and the average charge difference between any two sets of batteries is obtained.

[0085] S223: Calculate the charge transfer amount between any two sets of batteries after stopping charging at a preset charging time based on the conversion relationship between the open-circuit voltage and the state of charge, the average charge difference, and the average state of charge of the battery receiving charge in any two sets of batteries.

[0086] Among them, the conversion relationship between the open-circuit voltage and the state of charge can be a function. In this function, the state of charge is the independent variable and the open-circuit voltage is the dependent variable. For example: Among them, x represents the state of charge, OCV represents the open-circuit voltage, and k is a parameter.

[0087] Of course, the conversion relationship between the open-circuit voltage and the state of charge can be a corresponding relationship diagram of the open-circuit voltage and the state of charge of a pre-calibrated battery or cell. Figure 4 Schematic diagram of the corresponding relationship between the open-circuit voltage and the state of charge in the embodiment of the present application Figure 1 , in this diagram, the abscissa can represent the state of charge and the ordinate can represent the open-circuit voltage. Of course, the conversion relationship between the open-circuit voltage and the state of charge can also be embodied in other forms, which is not specifically limited here.

[0088] The average state of charge of the battery receiving charge can be obtained from S221, and the average charge difference between the two batteries can be obtained from S222. Furthermore, in combination with the conversion relationship between the open-circuit voltage and the state of charge, based on the fact that the open-circuit voltage of the battery receiving charge is the same as that of the battery sending charge after charge transfer, through the conversion between the open-circuit voltage and the state of charge, the charge transfer amount between any two sets of batteries after stopping charging at a preset charging time can be calculated.

[0089] As can be seen from the above, the average charge difference between the two sets of batteries is calculated based on the average state of charge corresponding to the two sets of batteries. Since there are often multiple battery cells in a battery, and the state of charge of each battery cell may vary, therefore, the average state of charge can more truly represent the state of charge level of each battery cell in the battery, and thus more accurately determine the amount of charge transfer between the two sets of batteries.

[0090] Based on the above embodiments, calculating the amount of charge transfer between any two sets of batteries after stopping charging at the preset charging time, that is, in step S223, specifically may include:

[0091] According to

[0092] OCV(SOC avg +k·SOC trans )=OCV(SOC avg +ΔSOC-SOC trans ) Formula (1)

[0093] Calculate the amount of charge transfer between any two sets of batteries after stopping charging at the preset charging time.

[0094] Among them, OCV() represents the conversion relationship between the open-circuit voltage and the state of charge. SOC avg represents the average state of charge of the battery receiving the charge. ΔSOC represents the average charge difference between any two sets of batteries. k represents the battery aging coefficient. SOC trans represents the amount of charge transfer between any two sets of batteries.

[0095] In the specific calculation process, it may include the following steps:

[0096] Step 1-1: In formula (1), set SOC trans =0.

[0097] Step 1-2: Determine whether formula (1) holds; if it holds, retain the value of SOC trans set at this time; if it does not hold, then go to step 1-3.

[0098] Step 1-3: Reset SOC trans =SOC′ trans +0.01, and return to step 1-2. Among them, SOC′ trans is the value set in step 1-1.

[0099] Of course, data can also be directly used for solving. Specifically, it is to obtain the open-circuit voltage of the battery that receives charge after recharge, the open-circuit voltage of the battery that sends charge after recharge, the average state of charge of the battery that receives charge, the average charge difference between the two batteries, and the battery aging coefficient, and substitute the above data into formula (1) to calculate the charge transfer amount. The specific method for solving the charge transfer amount through formula (1) is not limited herein.

[0100] As can be seen from the above, in the process of calculating the charge transfer amount between two batteries based on the conversion relationship between the open-circuit voltage and the state of charge, the average charge difference between the two batteries, and the average state of charge of the battery that receives charge in the two batteries, the aging condition of the battery that receives charge, that is, the actual charge amount that the battery that receives charge can receive, is fully considered. By adding the battery aging coefficient in the process of calculating the charge transfer amount, the charge transfer amount between the two batteries can be determined more accurately, and further, whether the battery that receives charge will reach the critical overcharge state after stopping charging at the preset time can be determined more accurately, so as to control the charging of the battery pack more precisely.

[0101] Based on the above embodiments, before calculating the charge transfer amount between any two sets of batteries after stopping charging at the preset charging time according to OCV(SOC avg +k·SOC trans )=OCV(SOC avg +ΔSOC - SOC trans ), in order to determine the battery aging coefficient k in formula (1), it may specifically include:

[0102] Step A1: Obtain the theoretical open-circuit voltage and the actual open-circuit voltage of the battery that receives charge after mutual charging of any two sets of batteries last time.

[0103] That is to say, before charging the battery pack this time, first obtain the various parameters when charging the battery pack last time. Specifically, what is obtained is: the actual open-circuit voltage of the battery that receives charge measured by a voltage measuring instrument after the charging of the battery pack ended last time and the mutual charging of each battery in the battery pack was completed. And, the theoretical open-circuit voltage of the battery that receives charge after stopping charging at the preset charging time calculated in advance during the last charging control.

[0104] Step A2: Determine whether the theoretical open-circuit voltage is equal to the actual open-circuit voltage; if so, execute Step A3; if not, execute Step A4.

[0105] If the theoretical open-circuit voltage is equal to the actual open-circuit voltage, it means that the battery that receives charge did not further age during the last charging process. Then, in this charging control, the battery aging parameters used in the last charging control can be continued to be used.

[0106] If the theoretical open-circuit voltage is not equal to the actual open-circuit voltage, it indicates that during the previous charging process, the battery that received the charge has further aged. The theoretically calculated theoretical open-circuit voltage is different from the finally actually measured actual open-circuit voltage. Then, during this charging control, the battery aging parameter needs to be corrected.

[0107] Step A3: Use the battery aging coefficient used in the previous charging process as the battery aging coefficient.

[0108] Step A4: According to

[0109] OCV(SOC avg +k·SOC trans计算 )=OCV(SOC avg +ΔSOC-SOC trans实际 ) Formula (2)

[0110]

[0111] Determine the battery aging coefficient.

[0112] Among them, OCV() represents the conversion relationship between the open-circuit voltage and the state of charge. SOC avg represents the average state of charge of the battery that received the charge. ΔSOC represents the average charge difference between any two groups of batteries. k represents the battery aging coefficient. SOC trans计算 represents the theoretical charge transfer amount between any two groups of batteries in the previous time. SOC trans实际 represents the actual charge transfer amount between any two groups of batteries in the previous time.

[0113] In the process of determining the battery aging coefficient according to Formula (2), the following steps may be included:

[0114] Step 2-1: In Formula (2), set k = 1.

[0115] Step 2-2: Determine whether Formula (2) holds; if it holds, retain the value of k set at this time; if it does not hold, then go to Step 2-3.

[0116] Step 2-3: Reset k = k′ - 0.01 and return to Step 2-2. Where k′ is the value set in Step 2-1.

[0117] Of course, it is also possible to directly solve using Formula (3). That is to say, directly divide the theoretically calculated theoretical charge transfer amount by the actually measured actual charge transfer amount during the previous charging process. For the specific method of determining the aging coefficient, no limitation is made here.

[0118] As can be seen from the above, during each charging control of the battery pack, it is necessary to correct the battery aging parameters so that the actual charge acquisition of the battery receiving charge can be accurately estimated during each charging control. Furthermore, it is possible to more accurately determine whether the battery receiving charge will reach the critical overcharge state after stopping charging at the preset time, thereby more precisely controlling the charging of the battery pack.

[0119] Based on the above embodiments, when determining the average state of charge corresponding to any two groups of batteries according to the state of charge, that is, in step S221, it may specifically include:

[0120] Step B1: Obtain the total open-circuit voltage corresponding to any two groups of batteries and the total number of battery cells.

[0121] The state of charge of the battery is not easily obtained directly, while the open-circuit voltage of the battery is easily obtained, that is, the open-circuit voltage of the battery can be measured by a voltage measuring instrument.

[0122] The number of battery cells in the battery is determined after the battery design is completed. Therefore, the total number of battery cells in the battery can be obtained from the design parameters of the battery.

[0123] Step B2: Determine the average open-circuit voltage corresponding to any two groups of batteries according to the total open-circuit voltage and the total number.

[0124] After obtaining the total open-circuit voltage corresponding to the two batteries and the total number of battery cells, by dividing the total open-circuit voltage by the total number, the average open-circuit voltage corresponding to the two batteries can be obtained.

[0125] Step B3: Determine the average state of charge of any two groups of batteries based on the average open-circuit voltage and the conversion relationship between the open-circuit voltage and the state of charge.

[0126] The state of charge of the battery cannot be directly obtained by measurement. Therefore, after obtaining the average open-circuit voltage corresponding to the two batteries, the average state of charge corresponding to the two batteries can be obtained through the conversion relationship between the open-circuit voltage and the state of charge.

[0127] In fact, the open-circuit voltage of each battery cell in the battery can be obtained separately through the Battery Management System (BMS). However, there will be a certain error each time an open-circuit voltage of a battery cell is obtained. When adding up the open-circuit voltages of all battery cells in the battery, the error of the overall open-circuit voltage of the battery will be even greater. Therefore, directly obtaining the total open-circuit voltage of the battery through one acquisition can reduce the error of the total battery voltage, and further make the determination of the state of charge of the two batteries more accurate.

[0128] Figure 5Schematic diagram of the correspondence between open-circuit voltage and state of charge in the embodiments of the present application Figure 2 , in this figure, the abscissa can represent the state of charge, and the ordinate can represent the open-circuit voltage. After obtaining the average open-circuit voltages corresponding to the two sets of batteries respectively, through Figure 5 the corresponding relationship in, the average state of charge corresponding to the two sets of batteries can be obtained. That is, draw a horizontal straight line for the corresponding average open-circuit voltage value on the ordinate, and find the point where it intersects with the Figure 5 curve in. Draw a perpendicular line at this point, and the state of charge corresponding to the intersection of the perpendicular line and the abscissa is the average state of charge corresponding to the two sets of batteries respectively.

[0129] As can be seen from the above, obtain the open-circuit voltage of each battery cell, and add up the open-circuit voltages of each battery cell, and then obtain the total open-circuit voltage of the battery. Since there will be a certain error every time an open-circuit voltage of a battery cell is obtained, and the open-circuit voltages of each battery cell are added up, then there will be a large error in the total open-circuit voltage of the battery obtained. By directly obtaining the total open-circuit voltage of the battery and determining the average open-circuit voltage of the battery based on the total open-circuit voltage of the battery, thereby determining the average state of charge of the battery, the error in obtaining the total open-circuit voltage of the battery can be reduced, and then the accuracy of determining the average state of charge of the battery can be improved. Furthermore, the amount of charge transfer can be determined more accurately, and then the accuracy of the charging control of the battery pack can be improved, and overcharging of the battery can be avoided more accurately.

[0130] Based on the above embodiments, Figure 6 is a schematic flowchart for determining whether the battery receiving charge is in a critical overcharge state in the embodiments of the present application. Refer to Figure 6 shown. When determining whether the battery receiving charge is in a critical overcharge state according to the amount of charge transfer, that is, in step S23, it may specifically include:

[0131] S231: In the battery receiving charge, determine the target battery cell with the highest state of charge before charge transfer.

[0132] In the battery receiving charge, if there are multiple battery cells, then among these multiple battery cells, it is necessary to first find the target battery cell with the highest state of charge before charge transfer. This is because: if there is no overcharge problem for this battery cell after recharge, then there will be no overcharge problem for other battery cells in the battery receiving charge. Subsequently, it is only necessary to determine whether the target battery cell will be in a critical overcharge state after receiving the transferred charge, which can improve the judgment efficiency of whether the battery is in a critical overcharge state, and then improve the real-time performance of the charging control of the battery pack.

[0133] S232: Determine whether the battery receiving charge is in a critical overcharge state according to the charge transfer amount, the state of charge of the target battery cell, the conversion relationship between the open-circuit voltage and the state of charge, and the warning voltage value.

[0134] After obtaining the state of charge of the target battery cell, by combining the charge transfer amount and the conversion relationship between the open-circuit voltage and the state of charge, the open-circuit voltage of the target battery cell after recharge can be known. Furthermore, by comparing the open-circuit voltage of the target battery cell after recharge with the warning voltage value, according to the comparison result, it can be determined whether the battery receiving charge is in a critical overcharge state.

[0135] Specifically, if the open-circuit voltage of the target battery cell after recharge is less than the warning voltage value, it indicates that there will be no overcharge problem when the target battery cell stops charging and recharges at this time. Then it is determined that the battery receiving charge is not in a critical overcharge state. If the open-circuit voltage of the target battery cell after recharge is equal to the warning voltage value, it indicates that there will be no overcharge problem when the target battery cell stops charging and recharges at this time. However, if charging continues at the next moment, the target battery cell will be overcharged after stopping charging and recharging. Then it is determined that the battery receiving charge has just reached the critical overcharge state. If the open-circuit voltage of the target battery cell after recharge is greater than the warning voltage value, it indicates that there will be an overcharge problem when the target battery cell stops charging and recharges at this time. Then it is determined that the battery receiving charge is already in a critical overcharge state.

[0136] As can be seen from the above, by determining whether there will be overcharge when the target battery cell with the highest state of charge before charge transfer in the battery receiving charge stops charging at the preset charging time, it can be determined whether there will be overcharge when the battery receiving charge stops charging at the preset charging time, which can reduce the calculation amount of the state of charge of the battery, and further improve the speed of determining whether the battery is in a critical overcharge state, thus improving the real-time performance of the battery pack charging control.

[0137] Based on the above embodiments, when determining whether the battery receiving charge is in a critical overcharge state according to the charge transfer amount, the state of charge of the target battery cell, the conversion relationship between the open-circuit voltage and the state of charge, and the warning voltage value, that is, in step S232, it may specifically include:

[0138] Step C1: Determine whether OCV(SOC avg +ΔSOC abn -k·SOC trans )≤V warning holds; if so, execute step C2; if not, execute step C3.

[0139] Step C2: Determine that the battery receiving charge is not in a critical overcharge state.

[0140] Step C3: Determine that the battery receiving charge is in a critical overcharge state.

[0141] Among them, OCV() represents the conversion relationship between the open-circuit voltage and the state of charge, SOC avg represents the average state of charge of the battery receiving charge, ΔSOC abn represents the difference between the state of charge of the target battery cell and SOC avg where k represents the battery aging coefficient, SOC trans represents the amount of charge transfer between any two groups of batteries, V warning represents the warning voltage value.

[0142] Figure 7 is a schematic diagram of the state of charge of the battery cells in each battery after mutual charging in the embodiment of the present application. Refer to Figure 7 As shown, in the battery pack, the first battery 701 is connected in parallel with the second battery 702. In the first battery 701, the first battery cell 7011 is connected in series with the second battery cell 7012. In the second battery 702, the third battery cell 7021 is connected in series with the fourth battery cell 7022. Assume that the first battery 701 transfers 20% of the charge amount to the second battery 702 (the first battery cell 7011 and the second battery cell 7012 each transfer out 10%). Before the charge transfer, the state of charge of the third battery cell 7021 is 95%, and the state of charge of the fourth battery cell 7022 is 75%. Then, after the charge transfer, the fourth battery cell 7022 receives 10% of the charge transfer amount, plus the original state of charge of 75%, and the state of charge of the fourth battery cell 7022 is 85%, and the corresponding open-circuit voltage does not exceed the warning voltage value. And the third battery cell 7021 receives 10% of the charge transfer amount, plus the original state of charge of 95%, and the state of charge of the third battery cell 7021 is 105%, and the corresponding open-circuit voltage has reached the warning voltage value. At this time, it is necessary to control to stop charging the battery pack. In this way, after stopping charging and backcharging, the battery pack reaches the maximum charging state, and the battery receiving charge will not be overcharged.

[0143] As can be seen from the above, when determining the open-circuit voltage of the target battery cell with the highest state of charge before charge transfer in the battery receiving charge after charge transfer, during the process of charge transfer to the target battery cell, the battery aging parameter is still considered, that is, considering the actual charge amount received by the target battery cell, the accuracy of determining the open-circuit voltage of the target battery cell after mutual charging can be improved, and further, it can be more accurately determined whether the battery receiving charge is in a critical overcharge state, thereby improving the accuracy of battery pack charging control.

[0144] Based on the above embodiments, Figure 8This is a schematic flowchart of the further charging control process in the embodiments of this application after determining that the battery is not in a critical overcharge state. Refer to Figure 8 As shown, after determining whether the battery receiving charge is in a critical overcharge state according to the charge transfer amount, it may further include:

[0145] S25: If it is determined that the battery receiving charge is not in a critical overcharge state, determine the state difference between the current state of charge of the battery receiving charge and the critical overcharge state.

[0146] S26: Determine whether the state difference is less than a preset difference; if not, execute S27; if so, execute S28.

[0147] S27: Charge the battery pack at a first charging rate after a preset charging time.

[0148] S28: Charge the battery pack at a second charging rate after a preset charging time, and the second charging rate is less than the first charging rate.

[0149] Specifically, when the state difference between the current state of charge of the battery receiving charge and the critical overcharge state is greater than or equal to the preset difference, it means that the battery receiving charge is still far from the critical overcharge state. Therefore, the battery pack can be charged at a relatively large first charging rate after a preset charging time. When the state difference between the current state of charge of the battery receiving charge and the critical overcharge state is less than the preset difference, it means that the battery receiving charge is already relatively close to the critical overcharge state. To avoid charging the battery pack too fast and not having enough time to judge whether the battery will be overcharged at a certain moment, which may lead to battery overcharge, therefore, the battery pack needs to be charged at a smaller second charging rate after a preset charging time.

[0150] In practical applications, the first charging rate can be the normal charging rate, that is, 100%, or it can be the fast charging rate, that is, greater than 100%. And the second charging rate is a slower charging rate, that is, less than 100%. The specific values of the first charging rate and the second charging rate are not limited here.

[0151] As can be seen from the above, the charging rate of the battery pack is determined according to the size of the state difference between the current state of charge of the battery receiving charge and the critical overcharge state. When the state difference is large, a higher charging rate can be used to continue charging the battery pack, which can shorten the charging time of the battery pack and improve the charging efficiency of the battery pack. When the state difference is small, a lower charging rate can be used to continue charging the battery pack, which can avoid the battery quickly passing through the critical overcharge state. When the battery is about to reach the critical overcharge state, the charging can be accurately controlled to stop, improving the accuracy of charging control.

[0152] Based on the same inventive concept, as an implementation of the above method, an embodiment of the present application further provides a charging control device for a battery pack. Figure 9 Structural schematic of the charging control device for the battery pack in the embodiment of the present application Figure 1 , see Figure 9 As shown, the device may include:

[0153] A determination module 901, configured to determine the state of charge corresponding to each battery after a preset charging time based on charging parameters;

[0154] A calculation module 902, configured to calculate the charge transfer amount between the batteries after stopping charging at the preset charging time according to the state of charge;

[0155] A judgment module 903, configured to judge whether the battery receiving charge is in a critical overcharge state according to the charge transfer amount;

[0156] A control module 904, configured to, if so, stop charging the battery pack after the preset charging time.

[0157] Further, as a refinement and extension of the Figure 9 device shown, an embodiment of the present application further provides a charging control device for a battery pack. Figure 10 Structural schematic of the charging control device for the battery pack in the embodiment of the present application Figure 2 , see Figure 10 As shown, the device may include:

[0158] A correction module 1001, specifically including:

[0159] A first correction unit 1001a, configured to obtain the theoretical open-circuit voltage and the actual open-circuit voltage of the battery receiving charge after mutual charging of any two groups of batteries last time.

[0160] A second correction unit 1001b, configured to judge whether the theoretical open-circuit voltage is equal to the actual open-circuit voltage. If so, enter the third correction unit 1001c. If not, enter the fourth correction unit 1001d.

[0161] A third correction unit 1001c, configured to use the battery aging coefficient used in the previous charging process as the battery aging coefficient.

[0162] A fourth correction unit 1001d, configured to determine the battery aging coefficient according to OCV(SOC avg +k·SOC trans计算 ) = OCV(SOC avg +ΔSOC - SOC trans实际 ) or determine the battery aging coefficient.

[0163] Among them, OCV() represents the conversion relationship between the open-circuit voltage and the state of charge, SOC avg represents the average state of charge of the battery receiving charge, ΔSOC represents the average charge difference between any two groups of batteries, k represents the battery aging coefficient, SOC trans计算 represents the theoretical charge transfer amount between any two groups of batteries in the previous time, SOC trans实际 represents the actual charge transfer amount between any two groups of batteries in the previous time.

[0164] The determination module 1002 is configured to determine the state of charge corresponding to each battery after a preset charging time based on the charging parameters.

[0165] The calculation module 1003 specifically includes:

[0166] The first calculation unit 1003a is configured to determine the average state of charge corresponding to any two groups of batteries according to the state of charge, where the two groups of batteries are two groups of batteries having a charge transfer relationship, and the state of charge is a set of the state of charge of each battery cell corresponding to each battery.

[0167] The first calculation unit 1003a is specifically configured to obtain the total open-circuit voltage corresponding to any two groups of batteries and the total number of battery cells. Determine the average open-circuit voltage corresponding to any two groups of batteries according to the total open-circuit voltage and the total number. Determine the average state of charge of any two groups of batteries based on the average open-circuit voltage and the conversion relationship between the open-circuit voltage and the state of charge.

[0168] The second calculation unit 1003b is configured to determine the average charge difference between any two groups of batteries according to the average state of charge.

[0169] The third calculation unit 1003c is configured to calculate the charge transfer amount between any two groups of batteries after stopping charging at the preset charging time based on the conversion relationship between the open-circuit voltage and the state of charge, the average charge difference, and the average state of charge of the battery receiving charge in any two groups of batteries.

[0170] The third calculation unit 1003c is specifically configured to calculate the charge transfer amount between any two groups of batteries after stopping charging at the preset charging time according to OCV(SOC avg +k·SOC trans )=OCV(SOC avg +ΔSOC-SOC trans ).

[0171] Among them, OCV() represents the conversion relationship between the open-circuit voltage and the state of charge, SOC avgrepresents the average state of charge of the battery receiving charge, ΔSOC represents the average charge difference between any two sets of batteries, k represents the battery aging coefficient, SOC trans represents the amount of charge transfer between any two sets of batteries.

[0172] The determination module 1004 specifically includes:

[0173] The first determination unit 1004a is used to determine the target battery cell with the highest state of charge before charge transfer among the batteries receiving charge.

[0174] The second determination unit 1004b is used to determine whether the battery receiving charge is in a critical overcharge state according to the amount of charge transfer, the state of charge of the target battery cell, the conversion relationship between the open-circuit voltage and the state of charge, and the warning voltage value.

[0175] The second determination unit 1004b is specifically used to, if OCV(SOC avg +ΔSOC abn -k·SOC trans )≤V watning holds, then it is determined that the battery receiving charge is not in a critical overcharge state. If OCV(SOC avg +ΔSOC abn -k·SOC trans )≤V warning does not hold, then it is determined that the battery receiving charge is in a critical overcharge state.

[0176] Among them, OCV() represents the conversion relationship between the open-circuit voltage and the state of charge, SOC avg represents the average state of charge of the battery receiving charge, ΔSOC abn represents the difference between the state of charge of the target battery cell and SOC avg , k represents the battery aging coefficient, SOC trans represents the amount of charge transfer between any two sets of batteries, and the any two sets of batteries are two sets of batteries with a charge transfer relationship, V warning represents the warning voltage value.

[0177] The control module 1005 is used to, if so, stop charging the battery pack after the preset charging time.

[0178] The control module 1005 is further configured to, if not, determine the state difference between the current state of charge of the battery receiving the charge and the critical overcharge state. When the state difference is greater than or equal to a preset difference, charge the battery pack at a first charging rate after the preset charging time. When the state difference is less than the preset difference, charge the battery pack at a second charging rate after the preset charging time, where the second charging rate is less than the first charging rate.

[0179] It should be noted here that the description of the above device embodiments is similar to the description of the above method embodiments and has similar beneficial effects to the method embodiments. For the technical details not disclosed in the device embodiments of the present application, please refer to the description of the method embodiments of the present application for understanding.

[0180] Based on the same inventive concept, an embodiment of the present application further provides an electronic device. Figure 11 For the structural schematic diagram of the electronic device in the embodiment of the present application, see Figure 11 As shown, the electronic device may include: a processor 1101, a memory 1102, and a bus 1103; wherein, the processor 1101 and the memory 1102 communicate with each other through the bus 1103; the processor 1101 is configured to call program instructions in the memory 1102 to execute the methods in the above one or more embodiments.

[0181] It should be noted here that the description of the above electronic device embodiments is similar to the description of the above method embodiments and has similar beneficial effects to the method embodiments. For the technical details not disclosed in the electronic device embodiments of the present application, please refer to the description of the method embodiments of the present application for understanding.

[0182] Based on the same inventive concept, an embodiment of the present application further provides a computer-readable storage medium, which may include: a stored program; wherein, when the program runs, it controls the device where the storage medium is located to execute the methods in the above one or more embodiments.

[0183] It should be noted here that the description of the above storage medium embodiments is similar to the description of the above method embodiments and has similar beneficial effects to the method embodiments. For the technical details not disclosed in the storage medium embodiments of the present application, please refer to the description of the method embodiments of the present application for understanding.

[0184] Finally, summarize the main process of the charging control of the battery pack provided in the embodiments of the present application.

[0185] First, before charging the battery pack this time, according to OCV(SOC avg +k·SOC trans计算 )=OCV(SOC avg+ΔSOC - SOC trans实际 ) or Determine the battery aging coefficient.

[0186] Among them, OCV() represents the conversion relationship between the open circuit voltage and the state of charge. SOC avg represents the average state of charge of the battery receiving charge. ΔSOC represents the average charge difference between any two groups of batteries. k represents the battery aging coefficient. SOC trans计算 represents the theoretical charge transfer amount between any two groups of batteries in the previous time. SOC trans实际 represents the actual charge transfer amount between any two groups of batteries in the previous time.

[0187] Then, according to OCV(SOC avg + k·SOC trans ) = OCV(SOC avg +ΔSOC - SOC trans ) Calculate the charge transfer amount between any two groups of batteries after stopping charging at the preset charging time.

[0188] Among them, OCV() represents the conversion relationship between the open circuit voltage and the state of charge. SOC avg represents the average state of charge of the battery receiving charge. ΔSOC represents the average charge difference between any two groups of batteries. k represents the battery aging coefficient. SOC trans represents the charge transfer amount between any two groups of batteries.

[0189] Finally, according to whether OCV(SOC avg +ΔSOC abn - k·SOC trans ) ≤ V warning holds. If it holds, it is determined that the battery receiving charge is not in a critical overcharge state, and then it is determined to continue charging the battery pack. If it does not hold, it is determined that the battery receiving charge is in a critical overcharge state, and then it is determined to stop charging the battery pack.

[0190] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be covered within the scope of the claims and the description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed in the text, but includes all technical solutions falling within the scope of the claims.

Claims

1. A charging control method for a battery pack, characterized in that, The battery pack includes at least two groups of batteries connected in parallel, and the method includes: Determining the state of charge (SOC) corresponding to each battery after a preset charging time based on charging parameters; Calculating the charge transfer amount between the batteries after stopping charging at the preset charging time according to the SOC; Judging whether the battery receiving charge is in a critical overcharge state according to the charge transfer amount; If so, stopping charging the battery pack after the preset charging time.

2. The method according to claim 1, characterized in that, The SOC is a set of the state of charge of each cell corresponding to each battery in the batteries; The calculating the charge transfer amount between the batteries after stopping charging at the preset charging time according to the SOC includes: Determining the average SOC corresponding to any two groups of batteries, where the any two groups of batteries are two groups of batteries having a charge transfer relationship, according to the SOC; Determining the average charge difference between the any two groups of batteries according to the average SOC; Calculating the charge transfer amount between the any two groups of batteries after stopping charging at the preset charging time based on the conversion relationship between the open-circuit voltage and the SOC, the average charge difference, and the average SOC of the battery receiving charge in the any two groups of batteries.

3. The method according to claim 2, wherein The calculating the charge transfer amount between the any two groups of batteries after stopping charging at the preset charging time based on the conversion relationship between the open-circuit voltage and the SOC, the average charge difference, and the average SOC of the battery receiving charge in the any two groups of batteries includes: According to OCV(SOC avg +k·SOC trans ) = OCV(SOC avg +ΔSOC - SOC trans ) calculate the charge transfer amount between any two sets of batteries after stopping charging at the preset charging time; Among them, OCV() represents the conversion relationship between the open-circuit voltage and the state of charge, SOC avg represents the average state of charge of the battery receiving charge, ΔSOC represents the average charge difference between any two sets of batteries, k represents the battery aging coefficient, SOC trans represents the amount of charge transfer between any two sets of batteries.

4. The method according to claim 3, wherein In the OCV(SOC avg +k·SOC trans ) = OCV(SOC avg +ΔSOC - SOC trans ) before calculating the charge transfer amount between any two sets of batteries after stopping charging at the preset charging time, the method further includes: Obtaining the theoretical open-circuit voltage and the actual open-circuit voltage of the battery receiving charge after the last mutual charging of the any two groups of batteries; Judging whether the theoretical open-circuit voltage is equal to the actual open-circuit voltage; If so, using the battery aging coefficient used in the previous charging process as the battery aging coefficient; If not, then according to OCV(SOC avg +k·SOC trans计算 ) = OCV(SOC avg +ΔSOC - SOC trans实际 ) or determine the battery aging coefficient; Among them, OCV() represents the conversion relationship between the open-circuit voltage and the state of charge, SOC avg represents the average state of charge of the battery receiving charge, ΔSOC represents the average state-of-charge difference between any two sets of batteries, k represents the battery aging coefficient, SOC trans计算 represents the theoretical charge transfer amount between any two sets of batteries last time, SOC trans实际 represents the actual charge transfer amount between any two sets of batteries last time.

5. The method according to claim 2, characterized in that, The determining the average SOC corresponding to any two groups of batteries according to the SOC includes: Obtaining the total open-circuit voltage corresponding to the any two groups of batteries and the total number of battery cells; Determining the average open-circuit voltage corresponding to the any two groups of batteries according to the total open-circuit voltage and the total number; Determining the average SOC of the any two groups of batteries based on the average open-circuit voltage and the conversion relationship between the open-circuit voltage and the SOC.

6. The method according to claim 1, characterized in that, The judging whether the battery receiving charge is in a critical overcharge state according to the charge transfer amount includes: Determining a target battery cell with the highest SOC before charge transfer in the battery receiving charge; Judging whether the battery receiving charge is in a critical overcharge state according to the charge transfer amount, the SOC of the target battery cell, the conversion relationship between the open-circuit voltage and the SOC, and the warning voltage value.

7. The method according to claim 6, wherein The judging whether the battery receiving charge is in a critical overcharge state according to the charge transfer amount, the SOC of the target battery cell, the conversion relationship between the open-circuit voltage and the SOC, and the warning voltage value includes: If OCV(SOC avg +ΔSOC abn -k·SOC trans )≤V warning holds, it is determined that the battery receiving the charge is not in a critical overcharge state; If OCV(SOC avg +ΔSOC abn -k·SOC trans ) ≤ V warning does not hold, it is determined that the battery receiving the charge is in a critical overcharge state; Among them, OCV() represents the conversion relationship between the open-circuit voltage and the state of charge, and SOC avg represents the average state of charge of the battery receiving the charge, and ΔSOC abn represents the difference between the state of charge of the target battery cell and SOC avg , k represents the battery aging coefficient, and SOC trans represents the amount of charge transfer between any two sets of batteries, where the any two sets of batteries are two sets of batteries having a charge transfer relationship, and V warning represents the warning voltage value.

8. The method according to claim 1, characterized in that After the judging whether the battery receiving charge is in a critical overcharge state according to the charge transfer amount, the method further includes: If not, determining the state difference between the current SOC of the battery receiving charge and the critical overcharge state; When the state difference is greater than or equal to a preset difference, the battery pack is charged at a first charging rate after the preset charging time; When the state difference is less than the preset difference, the battery pack is charged at a second charging rate after the preset charging time, and the second charging rate is less than the first charging rate.

9. A charging control device for a battery pack, characterized in that, The battery pack includes at least two groups of batteries connected in parallel, and the device includes: A determination module, configured to determine the state of charge corresponding to each battery respectively after a preset charging time based on charging parameters; A calculation module, configured to calculate the amount of charge transfer between the batteries after charging stops at the preset charging time according to the state of charge; A judgment module, configured to judge whether the battery receiving charge is in a critical overcharge state according to the amount of charge transfer; A control module, configured to, if so, stop charging the battery pack after the preset charging time.

10. An electronic device, characterized in that, including: A processor, a memory, and a bus; wherein, the processor and the memory complete communication with each other through the bus; The processor is configured to call program instructions in the memory to execute the method according to any one of claims 1 to 8.

11. A computer-readable storage medium, characterized in that, including: A stored program; wherein, when the program runs, it controls the device where the storage medium is located to execute the method according to any one of claims 1 to 8.

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