Battery cell short circuit identification method and device, BMS, battery pack, equipment and medium

Abstract

The application provides a kind of electric core short circuit identification method, device, BMS, battery pack, equipment and medium, method includes: in the charging process, according to the preset sampling time point, the voltage of electric core at each sampling time point is obtained in turn;According to the voltage obtained at each sampling time point, whether the voltage of electric core appears sustained decline is judged;According to the judgment result, whether the electric core is short-circuited is determined.The scheme provided in the application does not need to disassemble the electric core, the execution cost of the scheme is low, and the efficiency is higher, and the identification result is no longer dependent on the experience of personnel, and there is no error caused by subjective judgment, and the reliability is higher.

Description

Technical Field

[0001] This application relates to the field of batteries, specifically to a method, device, BMS, battery pack, equipment, and medium for identifying short circuits in battery cells. Background Technology

[0002] The negative electrode material of lithium-ion battery cells is mainly graphite carbon. During low-temperature charging or high-rate charging, significant polarization occurs inside the cell. Sustained polarization can easily lead to lithium plating, forming lithium dendrites that can puncture the separator and cause a short circuit between the positive and negative electrodes inside the cell. When the short circuit area expands to a certain extent, it will trigger thermal runaway, causing a serious battery safety accident. Therefore, it is necessary to detect short circuits within the cell in advance.

[0003] Currently, the most common method for determining whether a short circuit has occurred within a battery cell is to disassemble the cell and visually assess the severity of lithium plating. However, this method requires disassembling the cell, which poses certain safety hazards and is also costly in terms of manpower and resources, resulting in high implementation costs and low efficiency, hindering its widespread adoption in industrial applications. Furthermore, this method relies heavily on human experience and is susceptible to subjective errors, leading to low reliability. Summary of the Invention

[0004] The purpose of this application is to provide a method, device, BMS, battery pack, equipment, and medium for identifying short circuits inside battery cells, so as to improve the efficiency and reliability of short circuit identification.

[0005] In a first aspect, embodiments of this application provide a method for identifying short circuits in a battery cell, comprising: sequentially acquiring the voltage of the battery cell at each sampling time point during charging according to a preset sampling time point; determining whether the voltage of the battery cell continuously decreases based on the voltage acquired at each sampling time point; and determining whether the battery cell is short-circuited based on the determination result.

[0006] In practical applications, the voltage of a normal battery cell should continuously rise during charging. However, if a short circuit occurs within the cell, meaning the positive and negative electrodes inside the cell have become connected, it will cause an abnormal drop in the cell voltage. The technical solution of this application, based on this mechanism, can quickly determine if a battery cell is short-circuited by judging whether the voltage continuously drops during charging. Compared to existing solutions, it eliminates the need to disassemble the battery cell, resulting in lower execution costs and higher efficiency. Furthermore, the identification result no longer relies on human experience and judgment, eliminating errors caused by subjective judgment and thus improving reliability.

[0007] In some embodiments, determining whether a battery cell is short-circuited based on the determination result includes: determining that the battery cell is short-circuited when the voltage of the battery cell continuously decreases.

[0008] In the above technical solution, a short circuit in the battery cell is determined when the voltage of the battery cell continues to drop. This ensures the effective detection of short circuits and avoids serious battery safety accidents caused by short circuits.

[0009] In some embodiments, determining whether a battery cell is short-circuited based on the determination result includes: when the voltage of the battery cell continuously decreases, determining whether the continuous decrease in the voltage of the battery cell is greater than a preset voltage fluctuation range; if it is greater, determining that the battery cell is short-circuited.

[0010] Considering that in practical applications, when collecting voltage data from battery cells, the data may fluctuate due to limitations in the accuracy of the data acquisition devices. This could result in a situation where the battery cell appears normal, but the collected voltage shows a slight, continuous decrease. The above technical solution addresses this by pre-setting a voltage fluctuation range. Only when the continuous voltage drop exceeds this range is a short circuit confirmed for the battery cell. This eliminates the possibility of a continuous voltage drop caused by the accuracy of the data acquisition devices, thereby reducing false positives and improving the reliability of identifying whether a battery cell is short-circuited.

[0011] In some embodiments, the voltage fluctuation range is the voltage acquisition accuracy of the battery management system.

[0012] In the above technical solution, the voltage fluctuation range is set to the voltage acquisition accuracy of the battery management system. This can eliminate the situation where the cell voltage continues to drop due to the acquisition accuracy of the acquisition device, while timely identifying the cell short circuit, reducing the risk of missing the cell short circuit and improving the reliability of cell short circuit identification.

[0013] In some embodiments, determining whether the cell voltage is continuously decreasing based on the voltage obtained at each sampling time point includes: when the cell voltage is obtained at the current sampling time point, determining whether the voltage at the current sampling time point is less than the voltage at the previous sampling time point; if the voltage at the current sampling time point is less than the voltage at the previous sampling time point, determining whether there is a marked sampling time point; if not, marking the previous sampling time point; if so, determining that the cell voltage has been continuously decreasing from the marked sampling time point to the current sampling time point.

[0014] In the above technical solution, by marking the sampling time point when a voltage drop occurs, the presence or absence of a marked sampling time point can quickly determine whether the cell voltage is continuously decreasing. The solution is simple to implement and highly efficient.

[0015] In some embodiments, the method further includes: if the voltage at the current sampling time point is greater than or equal to the voltage at the previous sampling time point, determining whether there is a marked sampling time point; if so, clearing the mark of the sampling time point.

[0016] In the above technical solution, by clearing the existing markings of the sampling time points after a voltage rise is detected, it is possible to accurately determine whether the cell voltage is continuously decreasing based on the existence of marked sampling time points, thus ensuring the reliability of the solution.

[0017] In some embodiments, determining whether a battery cell is short-circuited based on the judgment result includes: when the voltage of the battery cell continuously decreases, calculating the difference between the voltage at a marked sampling time point and the voltage at the current sampling time point; determining whether the difference is greater than a preset voltage fluctuation range; if it is greater, determining that the battery cell is short-circuited.

[0018] In the above technical solution, as long as the cell is still determined to have a continuously decreasing voltage at the current sampling time point, the difference between the voltage at the marked sampling time point and the voltage at the current sampling time point (i.e., the magnitude of the continuous voltage decrease to the current sampling time point) is calculated to determine whether the cell is short-circuited. Thus, if the magnitude of the continuous voltage decrease at the latest sampling time point exceeds a preset voltage fluctuation range, a cell short circuit can be determined, achieving the effect of timely detection of cell short circuits.

[0019] In some embodiments, the time interval between two adjacent sampling time points is less than or equal to 0.1 seconds.

[0020] Theoretically, the smaller the time interval between two adjacent sampling time points, the higher the voltage sampling frequency of the battery cell, making it easier to detect whether the battery cell experiences a continuous voltage drop during charging. In the above technical solution, the inventors found through extensive practical testing that when the time interval between two adjacent sampling time points is less than or equal to 0.1 seconds, it can effectively capture the continuous voltage drop caused by a battery cell short circuit, demonstrating good reliability in identifying battery cell short circuits.

[0021] In some embodiments, the method further includes: stopping charging all battery packs after determining that a cell is short-circuited; or, stopping charging the battery pack containing the cell after determining that a cell is short-circuited.

[0022] In the above technical solution, once a short circuit in a battery cell is confirmed, charging of all battery packs or the battery pack containing that particular cell is stopped. This effectively reduces the probability of battery safety accidents caused by short circuits in the battery cell during charging and improves the safety of the charging process.

[0023] In some embodiments, the method further includes: marking the cell after determining that the cell is short-circuited.

[0024] In the above technical solution, by marking the cells with short circuits, engineers can facilitate subsequent processing of the cells in the battery pack, such as disassembly and replacement.

[0025] Secondly, embodiments of this application also provide a battery cell short circuit identification device, comprising: an acquisition module, configured to sequentially acquire the voltage of the battery cell at each sampling time point during charging according to a preset sampling time point; and a judgment module, configured to determine whether the voltage of the battery cell continuously decreases based on the voltage acquired at each sampling time point, and determine whether the battery cell is short-circuited based on the judgment result.

[0026] In some embodiments, the determination module is specifically used to: determine that the battery cell is short-circuited when the voltage of the battery cell continues to drop.

[0027] In some embodiments, the determination module is specifically used to: when the voltage of the battery cell continuously decreases, determine whether the continuous decrease in the voltage of the battery cell is greater than a preset voltage fluctuation range; if it is greater, determine that the battery cell is short-circuited.

[0028] In some embodiments, the voltage fluctuation range is the voltage acquisition accuracy of the battery management system.

[0029] In some embodiments, the determination module is specifically used to: when the voltage of the battery cell is obtained at the current sampling time point, determine whether the voltage at the current sampling time point is less than the voltage at the previous sampling time point; if the voltage at the current sampling time point is less than the voltage at the previous sampling time point, determine whether there is a marked sampling time point; if not, mark the previous sampling time point; if there is, determine that the voltage of the battery cell has been continuously decreasing from the marked sampling time point to the current sampling time point.

[0030] In some embodiments, the determination module is further configured to: if the voltage at the current sampling time point is greater than or equal to the voltage at the previous sampling time point, determine whether there is a marked sampling time point; if so, clear the mark of the sampling time point.

[0031] In some embodiments, the determination module is specifically used to: when the voltage of the battery cell continuously decreases, calculate the difference between the voltage at the marked sampling time point and the voltage at the current sampling time point; determine whether the difference is greater than a preset voltage fluctuation range; if it is greater, determine that the battery cell is short-circuited.

[0032] In some embodiments, the time interval between two adjacent sampling time points is less than or equal to 0.1 seconds.

[0033] In some embodiments, the cell short circuit identification device further includes a control module for stopping charging all battery packs after determining that a cell is short-circuited; or for stopping charging the battery pack containing the cell after determining that a cell is short-circuited.

[0034] In some embodiments, the cell short-circuit identification device further includes a marking module for marking the cell after a short circuit is determined.

[0035] Thirdly, this application also provides a BMS (Battery Management System), including: a battery sampling chip for connecting to each cell of the battery pack to sequentially acquire the voltage of the cell at each sampling time point during charging according to a preset sampling time point; and a control chip for communicating with the battery sampling chip to determine whether the voltage of the cell is continuously decreasing based on the voltage acquired at each sampling time point, and to determine whether the cell is short-circuited based on the determination result.

[0036] In some embodiments, the control chip is also used to execute preset program instructions to implement any of the above-described cell short-circuit identification methods.

[0037] Fourthly, embodiments of this application also provide a battery pack, including: a battery group and a battery management system of any of the above; the battery group has multiple battery cells; each battery cell is connected to a battery sampling chip of the battery management system.

[0038] Fifthly, embodiments of this application also provide an electrical device, including the battery pack described above.

[0039] Sixthly, embodiments of this application also provide a computer-readable storage medium storing one or more program instructions that can be executed by a battery management system to implement the cell short-circuit identification method as described above. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of the structure of a single battery cell provided in an embodiment of this application;

[0042] Figure 2 This is a schematic diagram of the structure of a battery pack provided in an embodiment of this application;

[0043] Figure 3 A flowchart illustrating a cell short-circuit identification method provided in an embodiment of this application;

[0044] Figure 4 A schematic diagram illustrating the voltage change of a battery cell during charging, provided as an embodiment of this application;

[0045] Figure 5 A schematic diagram of a battery cell short-circuit identification device provided in an embodiment of this application;

[0046] Figure 6 This is a schematic diagram of a vehicle structure provided in an embodiment of this application. Detailed Implementation

[0047] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0049] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more (including two), unless otherwise explicitly defined.

[0050] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0051] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0052] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also extensively used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars.

[0053] In these fields, the most commonly used power batteries are lithium-ion batteries (i.e., batteries composed of lithium-ion cells). The inventors have noted that the negative electrode material of current lithium-ion cells is mainly graphite carbon. During low-temperature charging or high-rate charging, significant polarization occurs within the cell. Sustained polarization easily leads to lithium deposition, forming lithium dendrites that pierce the separator, causing a short circuit between the positive and negative electrodes inside the cell. When the short circuit area expands to a certain extent, it will trigger thermal runaway, resulting in a serious battery safety accident. Therefore, it is necessary to determine in advance whether a short circuit has occurred within the cell.

[0054] The inventors further noted that the most common method for determining whether a short circuit has occurred within a battery cell is to disassemble the cell and visually assess the severity of lithium plating before drawing a conclusion. However, this method requires disassembling the cell, which poses certain safety hazards and consumes significant manpower and resources, resulting in high implementation costs and low efficiency, hindering its widespread adoption in industrial applications. Furthermore, this method relies heavily on human experience, which can lead to errors due to subjective judgment, resulting in low reliability.

[0055] Furthermore, the inventors have noted that in practical applications, during charging of a normal battery cell (i.e., a cell without short circuits), the cell voltage and its SOC (State of Charge) correspond one-to-one. When the cell is charging, lithium ions are released from the positive electrode, a process that corresponds to an increase in the positive electrode potential. Conversely, at the negative electrode, lithium ions are inserted into the graphite carbon, a process that causes a decrease in the negative electrode potential. Since the cell voltage equals the positive electrode potential minus the negative electrode potential, the voltage of a normal battery cell must increase during charging.

[0056] Lithium plating often occurs during the charging process. If lithium plating occurs in the battery cell during charging, forming lithium dendrites that pierce the separator and cause a short circuit between the positive and negative electrodes inside the battery cell, the battery cell will exhibit self-discharge, resulting in an abnormal and continuous drop in voltage during charging.

[0057] Based on the above findings, in order to improve the efficiency and reliability of short circuit identification within battery cells, the inventors, through in-depth research, designed a battery cell short circuit identification method. By judging whether the voltage of the battery cell continuously drops during the charging process, the method can quickly determine whether the battery cell is short-circuited. Compared with existing solutions, this method eliminates the need to disassemble the battery cell, resulting in lower execution costs and higher efficiency. Furthermore, the identification results no longer rely on human experience and judgment, thus eliminating errors caused by subjective judgment and improving reliability.

[0058] To facilitate understanding of the solutions in the embodiments of this application, some basic information involved in the embodiments of this application will be introduced below:

[0059] In practical industrial applications, such as Figure 1 As shown, the battery cell 11, together with the end cap 12, the casing 13, and other functional components, constitutes a battery cell 100. Wherein:

[0060] End cap 12 refers to a component that covers the opening of housing 13 to isolate the internal environment of battery cell 100 from the external environment. The shape of end cap 12 can be adapted to the shape of housing 13 to fit it. Optionally, end cap 12 can be made of a material with certain hardness and strength (such as aluminum alloy), so that end cap 12 is not easily deformed under pressure and impact, allowing battery cell 100 to have higher structural strength and improved safety performance. Functional components such as electrode terminals 12a can be provided on end cap 12. Electrode terminals 12a can be used for electrical connection with battery cell 11 to output or input electrical energy to battery cell 100. In some embodiments, end cap 12 can also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of battery cell 100 reaches a threshold. The material of end cap 12 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this application embodiment does not impose any special limitations on this. In some embodiments, an insulating element may be provided on the inner side of the end cap 12. The insulating element can be used to isolate the electrical connection components within the housing 13 from the end cap 12 to reduce the risk of short circuits. For example, the insulating element may be made of plastic, rubber, etc.

[0061] The housing 13 is a component used to cooperate with the end cap 12 to form the internal environment of the battery cell 100, wherein the formed internal environment can accommodate the battery cell 11, electrolyte, and other components. The housing 13 and the end cap 12 can be independent components. An opening can be provided on the housing 13, and the end cap 12 closes the opening to form the internal environment of the battery cell 100. Alternatively, the end cap 12 and the housing 13 can be integrated. Specifically, the end cap 12 and the housing 13 can form a common connecting surface before other components are inserted into the housing. When it is necessary to encapsulate the interior of the housing 13, the end cap 12 closes the housing 13. The housing 13 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 13 can be determined according to the specific shape and size of the battery cell 11. The material of the housing 13 can be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this embodiment does not impose any special limitations on this.

[0062] The battery cell 11 is the component in the battery cell 100 where the electrochemical reaction occurs. The casing 13 may contain one or more battery cells 11. The battery cell 11 is mainly formed by winding or stacking positive and negative electrode plates, and a separator is usually provided between the positive and negative electrode plates. The portions of the positive and negative electrode plates containing active material constitute the main body of the battery cell assembly, while the portions of the positive and negative electrode plates without active material each constitute tabs 11a. The positive and negative tabs can be located together at one end of the main body or separately at both ends of the main body. During the charging and discharging process of the battery, the positive and negative active materials react with the electrolyte, and the tabs 11a connect the electrode terminals to form a current loop. However, when lithium plating occurs in the battery cell, lithium dendrites can pierce the separator, causing internal short circuits between the positive and negative electrode plates.

[0063] In this embodiment, the battery cell 100 is the smallest unit constituting a battery pack. A battery pack may contain multiple battery cells 100. These multiple battery cells 100 can be connected in series, parallel, or a combination thereof; a combination thereof means that multiple battery cells 100 can be connected in both series and parallel. Multiple battery cells 100 can be directly connected in series, parallel, or a combination thereof, and then the entire assembly of these multiple battery cells 100 can be housed in a box or other packaging to form a unit capable of external charging and discharging.

[0064] In practical applications, a single battery pack can serve as a single battery. However, it can also serve as a single battery by connecting multiple battery packs in series, parallel, or a combination thereof, and then housing them within a casing or other packaging. In other words, a single battery can contain one or more battery packs.

[0065] Each battery cell 100 can be a secondary battery or a primary battery. The battery cell 100 can be cylindrical, flat, cuboid, or other shapes.

[0066] Furthermore, in practical applications, battery packs are often used in conjunction with battery management systems to form a battery bundle that provides services to electrical devices, for example... Figure 2 As shown, the battery sampling chip of the battery management system (such as the AFE (analog front end) chip in the battery management system) can be connected to the tabs 11a of each cell 11 in the battery pack to acquire cell data, including voltage. The control chip of the battery management system (such as the MCU (Micro Controller Unit) in the battery management system) can then execute different strategies based on the data acquired by the battery sampling chip to achieve battery management.

[0067] Based on the above description, please refer to some embodiments of this application. Figure 3 As shown, Figure 3 This paper illustrates a basic flowchart of the cell short-circuit identification method provided in an embodiment of this application, including:

[0068] S301: According to the preset sampling time points, the voltage of the battery cell at each sampling time point during charging is obtained sequentially.

[0069] In this embodiment of the application, the time interval between sampling time points can be preset, so that the time point at the start of charging is taken as the first sampling time point. Based on the preset time interval, the voltage of the battery cell is collected sequentially to obtain the voltage of the battery cell at each sampling time point during the charging process.

[0070] It should be understood that, theoretically, the smaller the time interval between two adjacent sampling time points, the higher the voltage sampling frequency of the battery cell, and thus the easier it is to detect whether the battery cell experiences a continuous voltage drop during charging. However, a smaller time interval places higher demands on the voltage acquisition equipment used to collect the battery cell voltage. To reliably determine whether the battery cell voltage is continuously dropping within the capabilities of existing voltage acquisition equipment, the inventors, through extensive practical testing, discovered that a time interval of less than or equal to 0.1 seconds between two adjacent sampling time points can effectively capture continuous voltage drops caused by a battery cell short circuit, demonstrating good reliability in identifying battery cell short circuits. Therefore, in this embodiment, the time interval between two adjacent sampling time points can be set to less than or equal to 0.1 seconds. For example, the time interval between two adjacent sampling time points can be set between 10 milliseconds and 50 milliseconds, such as 30 milliseconds.

[0071] It should also be understood that the execution entity of the cell short-circuit identification method provided in this application embodiment can be a battery management system. The battery sampling chip of the battery management system can be connected to the positive and negative terminals of each cell in the battery pack, thereby collecting the voltage of each cell. Therefore, in practical applications, the time interval between two adjacent sampling time points can be set within a range of less than or equal to 0.1 seconds, according to the allowable operating frequency range of the battery sampling chip of the battery management system, in order to balance the voltage sampling effect and the performance requirements of the device.

[0072] S302: Based on the voltage obtained at each sampling time point, determine whether the voltage of the battery cell is continuously decreasing.

[0073] It should be noted that, in the embodiments of this application, the so-called continuous voltage decrease means that the voltage value of the battery cell continuously decreases at at least three consecutive sampling time points. For example, sampling time point 1, sampling time point 2, and sampling time point 3 are three consecutive sampling time points. Assuming that the voltage values ​​obtained at sampling time point 1, sampling time point 2, and sampling time point 3 are A1, A2, and A3 respectively, if A3 is less than A2 and A2 is less than A1, it can be determined that the voltage of the battery cell continuously decreases at sampling time point 1, sampling time point 2, and sampling time point 3.

[0074] It should be understood that in practical applications, in addition to determining whether the cell voltage is continuously decreasing based on whether the voltage value at at least three consecutive sampling time points is continuously decreasing, it is also possible to determine whether the cell voltage is continuously decreasing based on whether the voltage change value at at least two consecutive adjacent sampling time points is less than 0.

[0075] For example, assuming that sampling time points 1, 2, and 3 are three consecutive sampling time points, and that the voltage values ​​obtained at sampling time points 1, 2, and 3 are A1, A2, and A3 respectively, then in the judgment: if the voltage change value A2-A1 between sampling time point 2 and sampling time point 1 is less than 0, and the voltage change value A3-A2 between sampling time point 3 and sampling time point 2 is also less than 0, then it can be determined that the voltage of the battery cell continuously decreases at sampling time points 1, 2, and 3.

[0076] It should be understood that the two methods for determining whether the cell voltage is continuously decreasing are essentially the same in principle; the only difference lies in the execution logic required when implemented by a machine. In practical applications, engineers can configure the appropriate execution logic according to actual needs to determine whether the cell voltage is continuously decreasing.

[0077] In one optional embodiment of this application, after charging is completed, based on the voltage at all sampling time points collected during the charging process, it can be determined whether the voltage of the battery cell has continuously decreased during the charging process according to the sampling time sequence of each sampling time point.

[0078] Considering that lithium plating often occurs during charging in practical applications, and that internal short circuits within the battery cell are often caused by lithium dendrites formed during lithium plating piercing the separator, and that thermal runaway can occur when the short circuit area expands to a certain extent, leading to serious battery safety accidents, this application proposes an alternative embodiment to reduce the risk of serious battery safety accidents such as thermal runaway during charging. In this embodiment, the voltage of the battery cell is continuously measured at each sampling time point based on the latest acquired voltage data. This allows for the determination of whether a cell is short-circuited during charging. Thus, if a short circuit is detected in a cell during charging, charging of all battery packs can be stopped, or charging of the battery pack containing the identified short-circuited cell can be stopped, thereby reducing safety risks and improving charging safety.

[0079] In another optional implementation described above, each time the voltage of the battery cell corresponding to the current sampling time point is newly collected, the two methods for judging whether the voltage of the battery cell has continuously decreased can be used to re-judge the situation, thereby determining whether the voltage of the battery cell has continuously decreased up to the current sampling time point.

[0080] To improve judgment efficiency and reduce overhead during the judgment process, the following tag-based judgment method can also be used in this embodiment to determine whether the cell voltage has continuously decreased:

[0081] When the voltage of the battery cell is obtained at the current sampling time point, it is determined whether the voltage at the current sampling time point is less than the voltage at the previous sampling time point.

[0082] If the voltage at the current sampling time point is less than the voltage at the previous sampling time point, determine whether there is a marked sampling time point.

[0083] If it does not exist, mark the previous sampling time point of the current sampling time point.

[0084] If present, it is determined that the cell voltage has been continuously decreasing from the marked sampling time point to the current sampling time point.

[0085] It is important to note that if the voltage at the current sampling time point is greater than or equal to the voltage at the previous sampling time point, it is necessary to determine whether a marked sampling time point exists. If so, the mark for that sampling time point is cleared.

[0086] In the above method, once a voltage drop occurs during charging, the sampling time point at the beginning of the two sampling time points where the voltage drop occurs is marked. If a voltage rise occurs subsequently, the mark is cleared. In this way, each time a voltage drop occurs, the presence or absence of a marked sampling time point can determine whether there is a continuous voltage drop in the battery cell. Specifically, according to the above method, if the voltage at the current sampling time point is lower than the voltage at the previous sampling time point, and a marked sampling time point exists, not only can a continuous voltage drop in the battery cell be quickly determined, but it can also be further determined that the voltage drop in the battery cell has been continuous from the marked sampling time point to the current sampling time point.

[0087] S303: Based on the judgment result, determine whether the battery cell is short-circuited.

[0088] Considering that in practical applications, when collecting voltage data from battery cells, the data may fluctuate due to limitations in the accuracy of the data acquisition devices. This could result in a situation where the battery cell appears normal, but the collected voltage shows a slight, continuous decrease. Therefore, to reduce the probability of false identification, in an optional embodiment of this application, when a continuous decrease in the battery cell's voltage is detected, it can be determined whether the magnitude of the continuous voltage decrease exceeds a preset voltage fluctuation range. If it does, the battery cell is determined to be short-circuited; otherwise, it is determined that the battery cell is not short-circuited during the continuous voltage decrease phase.

[0089] For example, in the above optional embodiments, the voltage fluctuation range can be set by the engineer according to actual needs, such as being set to the voltage acquisition accuracy of the battery management system. This allows for timely identification of cell short circuits while eliminating the possibility of a continuous voltage drop in the battery cell caused by the acquisition accuracy of the acquisition device, reducing the risk of missed short circuits and improving the reliability of identifying whether a cell is short-circuited.

[0090] Of course, the voltage fluctuation range can also be set to be greater than or less than the voltage acquisition accuracy of the battery management system, and this application embodiment does not impose any restrictions on this.

[0091] It should be understood that, for the above optional implementation method, if step S302 adopts the judgment method based on marking described above, when the voltage of the battery cell continuously decreases, the difference between the voltage at the marked sampling time point and the voltage at the current sampling time point can be calculated, and then it can be determined whether the difference is greater than a preset voltage fluctuation range. If it is greater, the battery cell is determined to be short-circuited. Otherwise, the voltage at subsequent sampling time points is collected again, and the judgment is performed again.

[0092] In another optional embodiment of this application, a short circuit in the battery cell can be determined when the cell voltage shows a continuous drop. This ensures effective detection of short circuits and prevents serious battery safety accidents caused by short circuits.

[0093] It should be noted that, for a battery cell, as the charging process continues, the temperature inside the cell may rise. For a battery cell that has already developed lithium plating, the lithium dendrites may melt at high temperatures, causing the internal short circuit to disappear and resulting in a voltage drop followed by a rise. Therefore, in this embodiment, if a short circuit is detected even once during charging, the battery cell can be identified as a short-circuited problem cell.

[0094] In this embodiment of the application, after a short circuit in a battery cell is determined, the battery cell can be marked, which will facilitate engineers to perform subsequent processing such as disassembly and replacement of the battery cells in the battery pack based on the marking.

[0095] In the embodiments of this application, the marking method for the battery cell may include, but is not limited to, the following: the unique identifier of the battery cell can be recorded to mark the battery cell.

[0096] In this embodiment, the unique identifier of a battery cell can be the identifier of the battery pack in which the cell resides, as well as the cell's coordinates within the battery pack. This allows for accurate location of the battery pack containing the problematic cell based on the battery pack's identifier, and further, accurate location of the problematic cell within the battery pack based on its coordinates. Alternatively, the unique identifier can also be a unique code for each cell. Based on this unique code and relevant records from when the cell was loaded, the location of the problematic cell can be determined.

[0097] To facilitate understanding of the solutions provided in the embodiments of this application, the following example illustrates a specific implementation process for identifying short circuits in battery cells of an electric vehicle:

[0098] The battery management system detects whether the battery cells, battery pack, or the entire vehicle are in the charging gun insertion state. If so, the battery pack begins charging.

[0099] During the charging process, the battery management system (assuming the voltage acquisition accuracy of the battery management system is ΔV0 (for example, it can be 2mV)) continuously acquires the voltage of each cell at a preset time interval Δt (Δt≤0.1s), and calculates in real time whether the voltage at the current sampling time point has decreased compared to the voltage at the previous sampling time point.

[0100] If the voltage at the current sampling time point has not decreased compared to the voltage at the previous sampling time point, then determine whether a marked sampling time point already exists. If so, clear the mark.

[0101] If the voltage at the current sampling time point has decreased compared to the previous sampling time point, then determine whether a marked sampling time point already exists.

[0102] If it does not exist, then mark the previous sampling time point of the current sampling time point.

[0103] If it exists, calculate the difference ΔVt between the voltage at the current sampling time point and the voltage at the sampling time point of the marked point. If ΔVt > ΔV0, then it is determined that a short circuit has occurred in the cell.

[0104] For example, with Figure 4 Taking the cell voltage change as an example, in this example process, a voltage drop is first detected at the second sampling time point, so the first sampling time point is marked. At the second sampling time point, due to the voltage increase, the mark for the first sampling time point is cleared.

[0105] Then, a voltage drop was detected again at the 5th sampling time point, and the 4th sampling time point was marked.

[0106] Then, a voltage drop is observed at the 6th sampling time point. Since a marked sampling time point exists, the difference ΔV between the voltage at the 6th sampling time point and the voltage at the 4th sampling time point is calculated. 6-4 Assume ΔV 6-4 If the value is less than ΔV0, then continue to collect and judge the voltage at the 7th sampling time point.

[0107] Assumption Figure 4 The voltage difference ΔV up to the 9th sampling time point 9-4 If the voltage is greater than ΔV0, then when the voltage at the 9th sampling time point is collected, it can be determined that there is a short circuit in the cell.

[0108] After that, although Figure 4 The voltage continued to drop after the 9th sampling time point, but after it was determined that there was a short circuit in the cell, the aforementioned calculation and judgment were no longer required for subsequent sampling time points.

[0109] Once a battery cell with an internal short circuit is identified, charging is stopped, and the user can be notified to remove the charging gun.

[0110] Based on the same inventive concept, this application also provides a battery cell short-circuit identification device 500. Please refer to... Figure 5 As shown, Figure 5 It shows the use of Figure 3 The method shown pertains to a cell short-circuit identification device. It should be understood that the specific functions of device 500 are described above; to avoid repetition, detailed descriptions are omitted here. Device 500 includes at least one software function module that can be stored in memory or embedded in the operating system or firmware of device 500 in the form of software or firmware. Specifically:

[0111] See Figure 5 As shown, the device 500 includes: an acquisition module 501 and a judgment module 502. Wherein:

[0112] The acquisition module 501 is used to sequentially acquire the voltage of the battery cell at each sampling time point during charging according to the preset sampling time points;

[0113] The judgment module 502 is used to determine whether the voltage of the battery cell has continuously decreased based on the voltage obtained at each sampling time point, and to determine whether the battery cell is short-circuited based on the judgment result.

[0114] In one feasible embodiment of this application, the determination module 502 is specifically used to: determine that the battery cell is short-circuited when the voltage of the battery cell continues to drop.

[0115] In another feasible embodiment of this application, the determination module 502 is specifically used to: determine whether the continuous drop in voltage of the battery cell is greater than a preset voltage fluctuation range when the voltage of the battery cell continues to drop; if it is greater, determine that the battery cell is short-circuited.

[0116] In the above feasible implementation, the voltage fluctuation range is the voltage acquisition accuracy of the battery management system.

[0117] In this embodiment of the application, the determination module 502 is specifically used to: when the voltage of the battery cell is obtained at the current sampling time point, determine whether the voltage at the current sampling time point is less than the voltage at the previous sampling time point; if the voltage at the current sampling time point is less than the voltage at the previous sampling time point, determine whether there is a marked sampling time point; if not, mark the previous sampling time point; if there is, determine that the voltage of the battery cell has been continuously decreasing from the marked sampling time point to the current sampling time point.

[0118] In the above embodiment, the determination module 502 is further configured to: if the voltage at the current sampling time point is greater than or equal to the voltage at the previous sampling time point, determine whether there is a marked sampling time point; if so, clear the mark of the sampling time point.

[0119] In the above embodiment, the judgment module 502 is specifically used to: when the voltage of the battery cell continues to drop, calculate the difference between the voltage at the marked sampling time point and the voltage at the current sampling time point; determine whether the difference is greater than the preset voltage fluctuation range; if it is greater, determine that the battery cell is short-circuited.

[0120] In this embodiment of the application, the time interval between two adjacent sampling time points is less than or equal to 0.1 seconds.

[0121] In this embodiment of the application, the cell short circuit identification device 500 may further include a control module, which is used to stop charging all battery packs after determining that a cell is short-circuited; or to stop charging the battery pack containing the cell after determining that a cell is short-circuited.

[0122] In this embodiment of the application, the battery cell short circuit identification device 500 further includes a marking module for marking the battery cell after determining that it is short-circuited.

[0123] It should be understood that, for the sake of brevity, some of the content described in the previous method section will not be repeated in the device section.

[0124] This application also provides a battery management system and a battery pack in its embodiments. For example... Figure 2 As shown, the battery pack may include a battery assembly and a battery management system. The battery assembly contains multiple battery cells, each connected to a battery sampling chip in the battery management system.

[0125] A battery management system can include a battery sampling chip and a control chip.

[0126] The battery sampling chip connects to each cell in the battery pack to sequentially acquire the voltage of each cell at a preset sampling time point during charging. The control chip communicates with the battery sampling chip and determines whether the cell voltage is continuously decreasing based on the voltage acquired at each sampling time point, and determines whether the cell is short-circuited based on the determination result.

[0127] It should be understood that in the embodiments of this application, the battery sampling chip can be a component with cell voltage acquisition capability, such as an AFE in the battery management system, while the control chip can be a component with data processing capability, such as an MCU in the battery management system, but this is not a limitation.

[0128] It should also be understood that, in the embodiments of this application, the control chip can determine whether the voltage of the battery cell is continuously decreasing and whether the battery cell is short-circuited, in accordance with the specific method described in the preceding section, which will not be repeated here.

[0129] In this application embodiment, an electrical device is also provided, which includes the aforementioned battery pack.

[0130] It should be noted that, in the embodiments of this application, the electrical equipment can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0131] For example, see Figure 6 As shown, Figure 6 A structural diagram is shown when the electrical equipment is a vehicle 600. The vehicle 600 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery pack is installed inside the vehicle 600. The battery pack 601 can be located at the bottom, front, or rear of the vehicle 600, while the battery management system 602 can be located around the battery pack 601 or in a different area of ​​the vehicle 600. For example, the battery pack 601 can be located at the bottom of the vehicle 600, while the battery management system 602 can be located at the front of the vehicle 600.

[0132] The battery pack 601 can be used to power the vehicle 600; for example, the battery pack 601 can serve as the operating power source for the vehicle 600. The vehicle 600 may also include a motor 603, and the battery management system 602 can also be used to control the battery pack 601 to supply power to the motor 603, for example, to meet the power needs of the vehicle 600 during starting, navigation, and driving.

[0133] In some embodiments of this application, the battery pack 601 can not only serve as the operating power source for the vehicle 600, but also as the driving power source for the vehicle 600, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 600.

[0134] This application also provides a computer-readable storage medium, such as a floppy disk, optical disk, hard disk, flash memory, USB flash drive, SD (Secure Digital Memory Card), MMC (Multimedia Card), etc., in which one or more program instructions for implementing the above steps are stored. These one or more program instructions can be executed by the battery management system to implement the above-described cell short-circuit identification method. Further details will not be elaborated here.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural or step conflict, the various technical features mentioned in the various embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for identifying short circuits in battery cells, characterized in that, include: According to the preset sampling time points, the voltage of the battery cell at each of the sampling time points during charging is obtained sequentially; Based on the voltage obtained at each of the sampling time points, determine whether the voltage of the battery cell is continuously decreasing; Based on the judgment result, determine whether the battery cell is short-circuited; The determination of whether the voltage of the battery cell is continuously decreasing based on the voltage obtained at each sampling time point includes: When the voltage of the battery cell is obtained at the current sampling time point, it is determined whether the voltage at the current sampling time point is less than the voltage at the previous sampling time point. If the voltage at the current sampling time point is less than the voltage at the previous sampling time point, determine whether there is a marked sampling time point; if not, mark the previous sampling time point; if so, determine that the cell voltage has been continuously decreasing from the marked sampling time point to the current sampling time point. If the voltage at the current sampling time point is greater than or equal to the voltage at the previous sampling time point, determine whether there is a marked sampling time point; if so, clear the mark of that sampling time point.

2. The cell short-circuit identification method as described in claim 1, characterized in that, Based on the judgment result, determining whether the battery cell is short-circuited includes: When the voltage of the battery cell continues to drop, it is determined that the battery cell is short-circuited.

3. The cell short-circuit identification method as described in claim 1, characterized in that, Based on the judgment result, determining whether the battery cell is short-circuited includes: When the voltage of the battery cell continuously decreases, it is determined whether the magnitude of the continuous voltage decrease exceeds a preset voltage fluctuation range; If the value is greater than 1, the battery cell is determined to be short-circuited.

4. The cell short-circuit identification method as described in claim 3, characterized in that, The voltage fluctuation range refers to the voltage acquisition accuracy of the battery management system.

5. The cell short-circuit identification method as described in claim 1, characterized in that, Based on the judgment result, determining whether the battery cell is short-circuited includes: When the voltage of the battery cell continues to drop, calculate the difference between the voltage at the marked sampling time point and the voltage at the current sampling time point; Determine whether the difference is greater than a preset voltage fluctuation range; If the value is greater than 1, the battery cell is determined to be short-circuited.

6. The cell short-circuit identification method according to any one of claims 1-5, characterized in that, The time interval between two adjacent sampling time points is less than or equal to 0.1 seconds.

7. The cell short-circuit identification method according to any one of claims 1-5, characterized in that, The method further includes: Once a short circuit in the battery cell is confirmed, charging of all battery packs is stopped. Alternatively, after determining that the cell is short-circuited, stop charging the battery pack containing the cell.

8. The cell short-circuit identification method according to any one of claims 1-5, characterized in that, The method further includes: After determining that the cell is short-circuited, the cell is marked.

9. A battery cell short-circuit identification device, characterized in that, The apparatus is used to perform the cell short-circuit identification method according to any one of claims 1-8, and the apparatus comprises: The acquisition module is used to sequentially acquire the voltage of the battery cell at each of the preset sampling time points during charging; The judgment module is used to determine whether the voltage of the battery cell has continuously decreased based on the voltage obtained at each of the sampling time points, and to determine whether the battery cell is short-circuited based on the judgment result.

10. A battery management system, characterized in that, The battery management system is used to execute the cell short-circuit identification method according to any one of claims 1-8, and the battery management system includes: A battery sampling chip is used to connect to each cell of the battery pack to sequentially acquire the voltage of each cell at each preset sampling time point during charging; The control chip is communicatively connected to the battery sampling chip and is used to determine whether the voltage of the battery cell is continuously decreasing based on the voltage obtained at each sampling time point, and to determine whether the battery cell is short-circuited based on the determination result.

11. The battery management system as described in claim 10, characterized in that, The control chip is also used to execute preset program instructions to implement the cell short-circuit identification method as described in any one of claims 2-8.

12. A battery pack, characterized in that, include: The battery pack and the battery management system as described in claim 10 or 11; The battery pack has multiple cells; Each of the battery cells is connected to the battery sampling chip of the battery management system.

13. An electrical appliance, characterized in that, Includes the battery pack as described in claim 12.

14. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores one or more program instructions that can be executed by the battery management system to implement the cell short-circuit identification method as described in any one of claims 1-8.

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