Methods for detecting the connection status of the battery, management system, battery and power supply device

Abstract

This application provides a method, management system, battery, and power-consuming device for detecting the connection status of a battery pack, belonging to the field of battery technology. The method for detecting the connection status of the battery pack includes: performing electrochemical impedance spectroscopy (EIS) on a single battery cell to obtain the zero-crossing impedance of the battery cell, wherein the zero-crossing impedance is the impedance corresponding to the switching point between the positive and negative imaginary parts of the EIS; obtaining the ambient temperature during the EIS detection of the battery cell; and determining the connection status between the electrode terminals of the battery cell and the battery pack based on the zero-crossing impedance and the ambient temperature, wherein the battery pack connects multiple battery cells by connecting to the electrode terminals of the battery cells. This method enables the detection of the connection status between the electrode terminals of multiple battery cells within a battery and the battery pack, simplifying the detection process and effectively improving detection efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of batteries, in particular to a connection state detection method and management system of a busbar, a battery and a power utilization device. BACKGROUND

[0002] Energy saving and emission reduction is the key to the sustainable development of society. The rechargeable battery has the characteristics of storing or releasing energy as needed, and is widely used in various power utilization devices or energy storage systems, and is an important part of promoting energy transformation and sustainable development. For the new energy industry, battery technology is an important factor for its development.

[0003] In the production and use process of the battery, the connection between the busbar and the electrode terminal of the battery monomer is prone to problems such as virtual welding, loosening and corrosion, which may cause safety accidents such as overheating and fire, and affect the normal use of the battery. Therefore, how to monitor the connection state between the busbar and the electrode terminal of the battery monomer is an urgent problem to be solved. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the background art. To this end, one object of the present application is to provide a connection state detection method and management system of a busbar, a battery and a power utilization device to simplify the detection process and improve the detection efficiency.

[0005] The first aspect of the present application provides a connection state detection method of a busbar. The connection state detection method of the busbar comprises: performing electrochemical impedance spectroscopy (EIS) detection on a battery monomer to obtain a zero-crossing point impedance of the battery monomer, wherein the zero-crossing point impedance is the impedance corresponding to the positive and negative imaginary part value switching point in the electrochemical impedance spectroscopy; obtaining the environmental temperature when the electrochemical impedance spectroscopy (EIS) detection is performed on the battery monomer; and determining the connection state of the electrode terminal of the battery monomer and the busbar based on the zero-crossing point impedance and the environmental temperature, wherein the busbar is connected to the electrode terminal of the battery monomer to connect multiple battery monomers.

[0006] In the technical solution of the present application, the electrochemical impedance spectroscopy of the battery monomer is obtained to obtain the zero-crossing point impedance of the battery monomer. According to the obtained zero-crossing point impedance and the environmental temperature, the connection state of the electrode terminal of the battery monomer and the busbar can be quickly determined, the detection of the connection state of the electrode terminal of the multiple battery monomers included in the battery and the busbar is realized, the detection process is simplified, and the detection efficiency is effectively improved.

[0007] In some embodiments, determining the connection state of the electrode terminal of the battery monomer and the tab based on the zero-crossing point impedance and the ambient temperature comprises: correcting the zero-crossing point impedance according to the ambient temperature to obtain a corrected impedance; and determining the connection state of the electrode terminal of the battery monomer and the tab based on the corrected impedance and a preset impedance. By correcting the zero-crossing point impedance according to the ambient temperature to obtain a corrected impedance, and determining the connection state of the electrode terminal of the battery monomer and the tab based on the corrected impedance and a preset impedance, the deviation of the zero-crossing point impedance caused by temperature change is reduced, and the accuracy of detection is improved.

[0008] In some embodiments, determining the connection state of the electrode terminal of the battery monomer and the tab based on the zero-crossing point impedance and the ambient temperature comprises: determining the connection state of the electrode terminal of the battery monomer and the tab based on the correspondence between the zero-crossing point impedance and the frequency of the battery monomer, the correspondence between the temperature and the frequency, the zero-crossing point impedance, and the ambient temperature. By obtaining the zero-crossing point impedance and the correspondence between the zero-crossing point impedance and the frequency, the ambient temperature and the correspondence between the temperature and the frequency, the frequency can be quickly determined, the connection state of the electrode terminal of the battery monomer and the tab is determined according to the frequency, the detection process is simplified, and the detection efficiency is effectively improved.

[0009] In some embodiments, determining the connection state of the electrode terminal of the battery monomer and the tab based on the correspondence between the zero-crossing point impedance and the frequency of the battery monomer, the correspondence between the temperature and the frequency, the zero-crossing point impedance, and the ambient temperature comprises: determining a first frequency based on the zero-crossing point impedance and the correspondence between the zero-crossing point impedance and the frequency; determining a second frequency based on the ambient temperature and the correspondence between the temperature and the frequency; and determining the connection state of the electrode terminal of the battery monomer and the tab based on the first frequency and the second frequency. By the difference between the first frequency corresponding to the zero-crossing point impedance and the second frequency corresponding to the ambient temperature, the connection state of the electrode terminal of the battery monomer and the tab is determined, the frequency difference is amplified, and the determination process is simplified.

[0010] In some embodiments, the tab connection state detection method further comprises: in response to the connection state of the electrode terminal of the battery monomer and the tab being an abnormal state, accumulating the number of abnormal states to obtain an abnormal number; in response to the abnormal number being greater than a preset number, monitoring the voltage fluctuation of the battery monomer; and determining whether to perform fault warning based on the voltage fluctuation of the battery monomer. By accumulating the abnormal number to trigger voltage fluctuation monitoring, and then determining whether to perform fault warning, the probability of false alarm caused by occasional interference can be reduced, and the accuracy of the tab connection state detection result is improved.

[0011] In some embodiments, the connection state detection method of the tab further includes: in response to the number of exceptions being less than the preset number of times, re-performing the connection state detection of the tab on the battery cell. By re-performing the connection state detection of the tab when the number of exceptions is less than the preset number of times, the authenticity of the abnormal state is further verified, and the accuracy of the connection state detection result of the tab is improved.

[0012] In some embodiments, the connection state detection method of the tab further includes: in response to the voltage fluctuation of the battery cell being less than a preset voltage threshold, re-performing the connection state detection of the tab on the battery cell. By re-performing the connection state detection of the tab when the voltage fluctuation is less than the preset voltage threshold, the authenticity of the abnormal state is further verified, and the accuracy of the detection result is improved.

[0013] Embodiments of the second aspect of the present application provide a battery management system. The battery management system includes an EIS detection circuit and a controller, the EIS detection circuit is configured to perform EIS detection on the battery; the controller is in communication connection with the EIS detection circuit, and the controller is configured to perform the connection state detection method of the tab in the above-mentioned embodiments.

[0014] Embodiments of the third aspect of the present application provide a battery device. The battery device includes a battery and a battery management system in the above-mentioned embodiments.

[0015] Embodiments of the fourth aspect of the present application provide a power consumption device. The power consumption device includes a battery device in the above-mentioned embodiments.

[0016] The above description is only a summary of the technical solutions of the present application. In order to enable the technical means of the present application to be more clearly understood, and to be implemented according to the content of the description, and in order to enable the above and other purposes, characteristics and advantages of the present application to be more apparent and easy to understand, the following specific embodiments of the present application are described. BRIEF DESCRIPTION OF DRAWINGS

[0017] In the drawings, identical reference numerals designate identical or similar parts throughout the several views. The drawings are not necessarily to scale. It should be understood that the drawings only depict some embodiments in accordance with the present disclosure and should not be considered limiting of the scope of the disclosure.

[0018] Figure 1 Structure diagram of a vehicle of some embodiments of the present application;

[0019] Figure 2 Exploded structure diagram of a battery device of some embodiments of the present application;

[0020] Figure 3 Exploded structure diagram of a battery cell of some embodiments of the present application;

[0021] Figure 4 Flowchart of the connection state detection method of the pallet for some embodiments of the present application Figure 1 ;

[0022] Figure 5 Flowchart of the connection state detection method of the pallet for some embodiments of the present application Figure 1 ;

[0023] Figure 6 Flowchart of the connection state detection method of the pallet for some embodiments of the present application Figure 2 ;

[0024] Figure 7 Flowchart of the connection state detection method of the pallet for some embodiments of the present application Figure 2 . DETAILED DESCRIPTION

[0025] The embodiments of the technical solutions of the present application will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0026] 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 the present application belongs; the terms used herein are only for the purpose of describing specific embodiments of the present application, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0027] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0028] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0029] In the description of the embodiments of the present application, the term "and / or" is only to describe the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0030] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0031] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0032] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connecting", "connecting", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0033] At present, from the development of market situation, the application of rechargeable batteries is more and more widely. Rechargeable batteries are not only applied to energy storage power supply systems such as hydroelectric, thermal, wind and solar power stations, but also widely used in various electronic equipment, such as electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, military equipment and aerospace and many other fields. With the continuous expansion of the application field of rechargeable batteries, the market demand is also increasing.

[0034] In the production process of the battery, the busbar connects multiple battery monomers together to form a battery by connecting with the electrode terminals of the battery monomers. The busbar and the electrode terminals are usually connected together by welding or mechanical connection. In the production and use process of the battery, the connection between the busbar and the electrode terminals is prone to problems such as loose connection, corrosion, and the like, which may further cause safety accidents such as overheating and fire. Monitoring the connection state between the busbar and the electrode terminals can timely discover and handle these problems, and ensure the safe operation of the battery.

[0035] In the related art, the connection state between the busbar and the electrode terminals is usually detected by directly sampling the voltage at both ends of the busbar or by the current at both ends of the busbar. However, this method consumes the sampling resources of the analog front end (AFE) chip in the battery management system, which directly affects the monitoring accuracy, response speed and overall reliability of the battery management system, so generally only the positions of individual busbars in the battery are sampled, and the detection efficiency is low. In another way, the voltage of the battery monomer is monitored under a large current condition (such as 1000A), and the connection state between the busbar and the electrode terminals is determined according to the change of the voltage. However, since the voltage fluctuation of the battery monomer under a large current condition is related to the polarization, state of charge (SOC) and state of health (SOH) of the battery monomer in addition to the impedance factor, the accuracy of the connection state between the electrode terminals and the busbar obtained by this method is low.

[0036] Therefore, the embodiments of the present application disclose a busbar connection state detection method, which obtains the zero-crossing impedance of the battery monomer by obtaining the electrochemical impedance spectrum of the battery monomer, and quickly determines the connection state between the electrode terminals of the battery monomer and the busbar according to the obtained zero-crossing impedance and the ambient temperature, thereby realizing the detection of the connection state between the electrode terminals of multiple battery monomers included in the battery and the busbar, simplifying the detection process and effectively improving the detection efficiency.

[0037] The busbar connection state detection method disclosed in the embodiments of the present application can be used in an electric device or an energy storage device such as a vehicle, a ship or an aircraft, etc. The power supply system of the electric device or the energy storage device can be composed of the battery monomer and the battery disclosed in the present application, so that the detection process is simplified and the detection efficiency is effectively improved.

[0038] The embodiments of the present application provide a power consumption device using a battery as a power supply. The power consumption device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric car, an electric vehicle, a ship, a spacecraft, and the like. The electric toy can include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, an electric plane toy, and the like. The spacecraft can include an airplane, a rocket, a space shuttle, a spacecraft, and the like.

[0039] Please refer to Figure 1 , Figure 1 FIG. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present application. The vehicle 1000 can be a fuel automobile, a gas automobile, or a new energy automobile. The new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile. The vehicle 1000 is internally provided with a battery device 100. The battery device 100 can be arranged at the bottom, the head, or the tail of the vehicle 1000. The battery device 100 can be used for power supply of the vehicle 1000, for example, the battery device 100 can be used as an operating power supply of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power demand of the vehicle 1000 during starting, navigation, and driving.

[0040] In some embodiments of the present application, the battery device 100 can not only be used as an operating power supply of the vehicle 1000, but also be used as a driving power supply of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000.

[0041] Please refer to Figure 2 , Figure 2 FIG. 2 is an exploded structural schematic diagram of the battery device according to some embodiments of the present application. The battery device 100 includes a box body 10 and a battery monomer 20. The battery monomer 20 is accommodated in the box body 10. The box body 10 is used to provide an accommodation space for the battery monomer 20. The box body 10 can adopt various structures. In some embodiments, the box body 10 can include a first part 11 and a second part 12. The first part 11 and the second part 12 are mutually covered. The first part 11 and the second part 12 jointly define an accommodation space for accommodating the battery monomer 20. The second part 12 can be a hollow structure with one end open. The first part 11 can be a plate structure. The first part 11 covers the open side of the second part 12, so that the first part 11 and the second part 12 jointly define the accommodation space. The first part 11 and the second part 12 can also be hollow structures with one side open. The open side of the first part 11 covers the open side of the second part 12. Of course, the box body 10 formed by the first part 11 and the second part 12 can have various shapes, such as a cylinder, a cuboid, and the like.

[0042] In the battery 100, the battery cells 20 can be multiple, and the multiple battery cells 20 can be connected in series, in parallel, or in a mixed connection, where the mixed connection means that the multiple battery cells 20 are connected in both series and parallel. The multiple battery cells 20 can be directly connected in series, in parallel, or in a mixed connection, and the whole of the multiple battery cells 20 can be accommodated in the case 10. Of course, the battery 100 can also be in a form that the multiple battery cells 20 are first connected in series, in parallel, or in a mixed connection to form battery modules, and the multiple battery modules are then connected in series, in parallel, or in a mixed connection to form a whole, and the whole is accommodated in the case 10. The battery 100 can also include other structures, for example, the battery 100 can also include a current combiner for realizing the electrical connection between the multiple battery cells 20.

[0043] Each of the battery cells 20 can be a secondary battery or a primary battery, and can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto. The battery cell 20 can be in a shape of a cylinder, a flat body, a cuboid, or other shapes.

[0044] Please refer to Figure 3 , Figure 3 is a schematic diagram of an exploded view of a battery cell according to some embodiments of the present application. The battery cell 20 refers to the smallest unit that constitutes a battery. As Figure 3 , the battery cell 20 includes an end cover 21, a shell 22, an electrode assembly 23, and other functional components.

[0045] The end cover 21 refers to a component that covers the opening of the shell 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cover 21 can be adapted to the shape of the shell 22 to fit the shell 22. Optionally, the end cover 21 can be made of a material with certain hardness and strength, such as aluminum alloy, so that the end cover 21 is not easily deformed when subjected to extrusion and impact, so that the battery cell 20 can have higher structural strength and safety performance can also be improved. The end cover 21 can be provided with functional components such as an electrode terminal 211. The electrode terminal 211 can be used to electrically connect with the electrode assembly 23 for outputting or inputting the electrical energy of the battery cell 20. In some embodiments, the end cover 21 can also be provided with a pressure relief mechanism for relieving the internal pressure of the battery cell 20 when the internal pressure or temperature reaches a threshold value. The material of the end cover 21 can also be various, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc. In some embodiments, an insulating piece can also be provided on the inner side of the end cover 21, which can be used to isolate the electrical connection components in the shell 22 from the end cover 21 to reduce the risk of short circuit. Exemplarily, the insulating piece can be plastic, rubber, etc.

[0046] The housing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The housing 22 and the end cap 21 can be independent components. An opening can be provided on the housing 22, and the end cap 21 closes the opening to form the internal environment of the battery cell 20. Alternatively, the end cap 21 and the housing 22 can be integrated. Specifically, the end cap 21 and the housing 22 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 22, the end cap 21 closes the housing 22. The housing 22 can be of various shapes and sizes, such as cuboid, cylindrical, hexagonal prism, etc. Specifically, the shape of the housing 22 can be determined according to the specific shape and size of the electrode assembly 23. The housing 22 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0047] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The casing 22 may contain one or more electrode assemblies 23. The electrode assembly 23 is mainly formed by winding or stacking positive and negative electrode plates, and typically a separator is 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 electrode assembly, while the portions of the positive and negative electrode plates without active material each constitute a tab 231. The positive and negative tabs may 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 231 connect to the electrode terminals to form a current loop.

[0048] This application provides a method for detecting the connection status of a tablet. Figure 4 This is a flowchart illustrating the connection state detection method for bar membranes according to some embodiments of this application. Figure 1 ,refer to Figure 4 The connection status detection method 400 for bar tablets includes steps 410 to 430.

[0049] Step 410: Perform electrochemical impedance spectroscopy (EIS) on the battery cell to obtain the zero-crossing impedance of the battery cell, where the zero-crossing impedance is the impedance corresponding to the switching point of the positive and negative imaginary parts in the electrochemical impedance spectrum.

[0050] Step 420: Obtain the ambient temperature during electrochemical impedance spectroscopy (EIS) detection of the battery cells.

[0051] Step 430: Based on the zero-crossing impedance and ambient temperature, determine the connection state between the electrode terminals of the battery cell and the plate, wherein the plate connects multiple battery cells by connecting to the electrode terminals of the battery cell.

[0052] Electrochemical impedance spectroscopy (EIS) is an important analytical technique in the field of electrochemical testing. It provides information on charge transport, ion migration and diffusion, and electrode / electrolyte interface kinetics, which is crucial for determining the working mechanism of battery reactions and improving battery performance. It involves applying a small-amplitude sinusoidal potential or current perturbation to an electrochemical system, measuring the resulting current or potential response, and then plotting an impedance spectrum.

[0053] When testing electrochemical impedance spectroscopy, small-amplitude excitation signals of different frequencies can be applied to the battery, and the impedance at different frequencies can be calculated to obtain the electrochemical impedance spectrum of the battery. For example, it can be plotted as a Nyquist plot or a Bode plot.

[0054] After applying the appropriate excitation signal to the battery, the electrochemical impedance spectroscopy (EIS) of the battery can be obtained. The EIS can be used to analyze and obtain various electrochemical parameters, thereby enabling battery performance evaluation. In step 410, based on the obtained EIS, the zero-crossing impedance of the individual battery cells can be further determined. The zero-crossing impedance of the individual battery cells is the impedance corresponding to the switching point between the positive and negative imaginary parts in the EIS. For example, it can be the impedance where the imaginary part is 0 or close to 0 (including negative imaginary part values ​​close to 0, such as -0.00055, and positive imaginary part values ​​close to 0, such as 0.00055). The zero-crossing impedance of the individual battery cells can include the ohmic impedance of the individual battery cells, the ohmic impedance of the electrode plate, and the contact impedance (ohmic impedance) between the electrode plate and the electrode terminals of the individual battery cells. Typically, under otherwise constant conditions, the ohmic impedance of the individual battery cells and the ohmic impedance of the electrode plate are relatively stable, and the change in the zero-crossing impedance is mainly related to the contact impedance between the electrode plate and the electrode terminals of the individual battery cells.

[0055] The ambient temperature during electrochemical impedance spectroscopy (EIS) detection of a battery cell can be obtained through different detection methods. For example, a contact temperature sensor such as a thermistor can be used to directly contact the battery cell to detect its temperature, or a non-contact temperature sensor such as an infrared thermometer can be used to detect the temperature by pointing it at the area where the battery cell is located or directly at the battery cell.

[0056] In step 430, based on the zero-crossing impedance obtained in step 410 and the ambient temperature during electrochemical impedance spectroscopy detection of the battery cell obtained in step 420, the connection state between the electrode terminals of the battery cell and the electrode plate can be determined. In some embodiments, the zero-crossing impedance can be corrected using the ambient temperature to determine the connection state between the electrode terminals of the battery cell and the electrode plate; in other embodiments, the frequency corresponding to the zero-crossing impedance and the frequency corresponding to the ambient temperature can also be used to determine the connection state between the electrode terminals of the battery cell and the electrode plate. These methods will be described in detail below.

[0057] By obtaining the electrochemical impedance spectroscopy of a single battery cell, the zero-crossing impedance of the single cell can be obtained. Based on the obtained zero-crossing impedance and ambient temperature, the connection status between the electrode terminals and the electrode plate of the single cell can be quickly determined. This enables the detection of the connection status between the electrode terminals and the electrode plate of multiple battery cells in a battery, simplifying the detection process and effectively improving detection efficiency.

[0058] According to some embodiments of this application, Figure 5 This is a flowchart illustrating the process of determining the connection state in some embodiments of this application. Figure 1 ,refer to Figure 5 Step 430 includes steps 510 to 520.

[0059] Step 510: Correct the zero-crossing impedance based on the ambient temperature to obtain the corrected impedance;

[0060] Step 520: Based on the corrected impedance and the preset impedance, determine the connection status between the electrode terminals of the battery cell and the plate.

[0061] In this embodiment, a correction value for the zero-crossing impedance can be determined based on a predetermined relationship between temperature and zero-crossing impedance, as well as the ambient temperature. The zero-crossing impedance is corrected according to this correction value to obtain the corrected impedance. The connection status between the battery cell's electrode terminals and the circuit breaker is determined based on the difference between the corrected impedance and the preset impedance. If the difference between the corrected impedance and the preset impedance is greater than a preset impedance threshold, the connection status between the battery cell's electrode terminals and the circuit breaker is determined to be abnormal. If the difference between the corrected impedance and the preset impedance is less than or equal to the preset impedance threshold, the connection status between the battery cell's electrode terminals and the circuit breaker is determined to be normal.

[0062] In one embodiment, the corrected impedance is Z1, the preset impedance is Z0, and the preset impedance threshold is 0.1mΩ. If Z1-Z0>0.1mΩ, it can be determined that the connection between the electrode terminals of the battery cell and the circuit breaker is abnormal. If Z1-Z0≤0.1mΩ, it can be determined that the connection between the electrode terminals of the battery cell and the circuit breaker is normal.

[0063] For example, the relationship between temperature and zero-crossing impedance is shown in Table 1 below:

[0064]

[0065] The ambient temperature is 45℃, and the zero-crossing impedance Z is 0.375mΩ. According to the table above, the zero-crossing impedance corresponding to 25℃ is 0.41mΩ. When the ambient temperature is 45℃, the correction value for the zero-crossing impedance Z is 0.04mΩ. After correction, the impedance Z1 = Z + 0.04mΩ = 0.415mΩ, and the preset impedance Z0 is 0.41mΩ. If Z1 - Z0 ≤ 0.1mΩ, it can be determined that the connection between the electrode terminals of the battery cell and the plate is normal.

[0066] The zero-crossing impedance is corrected by ambient temperature to obtain the corrected impedance. Based on the corrected impedance and the preset impedance, the connection status between the electrode terminals of the battery cell and the plate is determined, which reduces the zero-crossing impedance offset caused by temperature changes and improves the accuracy of detection.

[0067] According to some embodiments of this application, step 430 above includes: determining the connection state between the electrode terminals of the battery cell and the plate based on the correspondence between the zero-crossing impedance and frequency of the battery cell, the correspondence between temperature and frequency, the zero-crossing impedance and the ambient temperature.

[0068] There is a corresponding relationship between zero-crossing impedance and frequency. When the connection between the electrode terminals of the battery cell and the circuit board is abnormal, the frequency corresponding to the zero-crossing impedance will shift. Therefore, the connection between the electrode terminals of the battery cell and the circuit board can be determined based on the frequency shift.

[0069] In this embodiment, the frequency corresponding to the zero-crossing impedance, i.e., the first frequency, can be determined based on the zero-crossing impedance and a predetermined correspondence between the zero-crossing impedance and frequency. The frequency corresponding to the ambient temperature, i.e., the second frequency, can be determined based on the ambient temperature and a predetermined correspondence between temperature and frequency.

[0070] Under normal conditions, meaning when the connection between the electrode terminals of the battery cell and the circuit breaker is normal, the first frequency and the second frequency are close to or the same. When the first frequency and the second frequency are different, and the difference is large, it indicates that the connection between the electrode terminals of the battery cell and the circuit breaker is abnormal.

[0071] In one embodiment, the connection state between the electrode terminals of the battery cell and the electrode plate can be determined based on the difference between the first frequency and the second frequency; in another embodiment, the connection state between the electrode terminals of the battery cell and the electrode plate can also be determined based on the ratio of the first frequency and the second frequency.

[0072] By obtaining the zero-crossing impedance and the corresponding relationship between the zero-crossing impedance and frequency, as well as the ambient temperature and the corresponding relationship between temperature and frequency, the frequency can be quickly determined. Based on the frequency, the connection status of the electrode terminals of the battery cell and the plate can be determined, which simplifies the detection process and effectively improves the detection efficiency.

[0073] According to some embodiments of this application, Figure 6 This is a flowchart illustrating the process of determining the connection state in some embodiments of this application. Figure 2 ,refer to Figure 6 The process 600 for determining the connection status includes steps 610 to 630.

[0074] Step 610: Determine the first frequency based on the zero-crossing impedance and the correspondence between the zero-crossing impedance and the frequency.

[0075] Step 620: Determine the second frequency based on the ambient temperature and the relationship between temperature and frequency.

[0076] Step 630: Based on the first frequency and the second frequency, determine the connection status between the electrode terminals of the battery cell and the plate.

[0077] In this embodiment of the application, the connection status between the electrode terminals of the battery cell and the plate can be determined based on the difference between the first frequency and the second frequency. When the difference between the first frequency and the second frequency is greater than a preset frequency threshold, it can be determined that the connection status between the electrode terminals of the battery cell and the plate is abnormal.

[0078] In one embodiment, the first frequency is f, the second frequency is f0, and the preset frequency threshold is 100 Hz. If f-f0<100Hz, it can be determined that the connection between the electrode terminal of the battery cell and the plate is normal; if f-f0≥100Hz, it can be determined that the connection between the electrode terminal of the battery cell and the plate is abnormal.

[0079] For example, the correspondence between zero-crossing impedance and frequency, and the correspondence between temperature and frequency are shown in Table 2 below:

[0080]

[0081] With a zero-crossing impedance of 0.4mΩ and an ambient temperature of 45℃, the first frequency f is 64Hz and the second frequency f0 is 10Hz, according to the table above. Since f-f0<100Hz, it can be determined that the connection between the electrode terminals of the battery cell and the plate is normal.

[0082] The connection status between the electrode terminals and the battery plate of a single cell is determined by the difference between the first frequency corresponding to the zero-crossing impedance and the second frequency corresponding to the ambient temperature. This amplifies the frequency difference and simplifies the determination process.

[0083] According to some embodiments of this application, the connection status detection method of the battery cell further includes: in response to an abnormal connection status between the electrode terminal of the battery cell and the battery cell, accumulating the number of abnormal states to obtain an abnormal number; in response to an abnormal number exceeding a preset number, monitoring the voltage fluctuation of the battery cell; and determining whether to issue a fault warning based on the voltage fluctuation of the battery cell.

[0084] In this embodiment, since the results of a single test may be random, the connection status between the electrode terminals and the electrode plate of the battery cell may be misjudged. To improve the accuracy of the test results, the number of abnormalities can be counted. If the number of abnormalities exceeds a preset number, it can be basically determined that the connection status between the electrode terminals and the electrode plate of the battery cell is abnormal.

[0085] To further determine if the connection status between the electrode terminals and the battery pack of a single battery cell is abnormal, it can be determined based on the voltage fluctuation of the battery cell. The voltage fluctuation of a battery cell refers to the real-time change in voltage during charging, discharging, and resting. Under normal circumstances, the voltage fluctuation of a battery cell remains within a stable range. If the connection status between the electrode terminals and the battery pack is abnormal, it will cause the battery cell's voltage to jump or fluctuate excessively. Therefore, a pre-set upper limit for voltage fluctuation based on battery type and application scenario can be used to determine the connection status between the electrode terminals and the battery pack.

[0086] In one embodiment, when the connection between the electrode terminals of a battery cell and the circuit breaker is abnormal, there may be additional contact resistance between the circuit breaker and the electrode terminals of the battery cell. Current flowing through the circuit breaker will generate a voltage, and this voltage will change linearly with the current. For example, under discharge conditions, the additional contact resistance between the circuit breaker and the electrode terminals of the battery cell is 100 microohms (µΩ). When the discharge current reaches 1000 amperes (A), a voltage drop of 100 millivolts (mV) will occur. That is, the voltage of a battery cell with an abnormal connection between its electrode terminals and the circuit breaker will be 100mV lower than the voltage of a battery cell with a normal connection.

[0087] Under charging conditions, the additional contact impedance between the electrode terminals of the battery cell and the electrode pad is 100uΩ. When the charging current reaches 1000A, a voltage rise of 100mV will occur. In other words, the voltage of a battery cell with an abnormal connection between the electrode terminals of the battery cell and the electrode pad will be 100mV higher than the voltage of a battery cell with a normal connection between the electrode terminals of the battery cell and the electrode pad.

[0088] By monitoring the voltage fluctuations of battery cells where the connection between the electrode terminals and the power strip is abnormal, the accuracy of the connection status detection can be further improved, thereby determining whether to issue a fault warning. In one example, a fault warning is issued when the voltage fluctuation of a battery cell exceeds a preset voltage threshold, where the preset voltage threshold can be the voltage fluctuation value of the battery cell when the connection between the electrode terminals and the power strip is normal.

[0089] By accumulating the number of abnormal events to trigger voltage fluctuation monitoring and then determining whether to issue a fault warning, the probability of false warnings caused by occasional interference can be reduced and the accuracy of the connection status detection results of the circuit breaker can be improved.

[0090] According to some embodiments of this application, the battery cell connection status detection method further includes: in response to the number of abnormalities being less than a preset number, re-detecting the battery cell connection status.

[0091] In this embodiment, since the results of a single test may be random, there may be misjudgments in determining the connection status between the electrode terminals of the battery cell and the electrode plate. To improve the accuracy of the test results, the number of abnormalities can be counted. If the number of abnormalities is less than a preset number, it indicates that the test results may have errors, and the connection status test of the electrode plate needs to be repeated.

[0092] By re-detecting the connection status of the tablets when the number of abnormalities is less than a preset number, the authenticity of the abnormal status is further verified, and the accuracy of the connection status detection results of the tablets is improved.

[0093] According to some embodiments of this application, the method for detecting the connection status of the battery cell further includes: re-detecting the connection status of the battery cell in response to the voltage fluctuation of the battery cell being less than a preset voltage threshold.

[0094] If the voltage fluctuation of a single battery cell is less than the preset voltage threshold, meaning the voltage of the single battery cell is within the normal range, it indicates that the connection between the electrode terminals of the single battery cell and the power strip is likely normal. However, issuing a fault warning in this case might result in an incorrect warning. To further improve the accuracy of the power strip connection status detection results, the connection status of the single battery cell can be re-detected.

[0095] By re-detecting the connection status of the battery when the voltage fluctuation is less than a preset voltage threshold, the authenticity of the abnormal state is further verified, and the accuracy of the detection results is improved.

[0096] Based on the same technical concept, embodiments of this application provide a battery management system. Figure 6 This is a schematic diagram of a battery management system according to some embodiments of this application, with reference to... Figure 6The battery management system 600 includes an EIS detection circuit 610 and a controller 620. The EIS detection circuit 610 is configured to perform EIS detection on the battery. The controller 620 is communicatively connected to the EIS detection circuit 610 and is configured to execute the battery connection status detection method in the above embodiments.

[0097] The implementation of the battery management system can refer to the implementation of the connection status detection method for the battery pack, and the repeated parts will not be described again.

[0098] In one embodiment, the controller 620 can be an integrated circuit chip with signal processing capabilities. During implementation, the steps of the above method embodiments can be completed by integrated logic circuits in the processor's hardware or by instructions in software form. The controller 620 can be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods and steps disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly embodied in the execution of a hardware decoding processor, or executed by a combination of hardware and software modules in the decoding processor. The software modules can reside in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. The storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method.

[0099] Based on the same technical concept, this application provides a battery device, which includes the battery management system described in the above embodiments.

[0100] Based on the same technical concept, this application provides an electrical device, which includes the battery device in the above embodiments.

[0101] A specific embodiment of this application is described below. It should be understood that this specific embodiment is described for illustrative purposes only and should not be construed as limiting the scope of this application.

[0102] Figure 7 This is a flowchart illustrating the connection state detection method for bar membranes according to some embodiments of this application. Figure 2 ,refer to Figure 7The method includes:

[0103] Step 701: Perform electrochemical impedance spectroscopy (EIS) on the individual battery cells to obtain the zero-crossing impedance of the individual battery cells.

[0104] Step 702: Obtain the ambient temperature during electrochemical impedance spectroscopy (EIS) detection of the battery cells.

[0105] Step 703: Correct the zero-crossing impedance based on the ambient temperature to obtain the corrected impedance.

[0106] Step 704: Based on the corrected impedance and the preset impedance, determine the connection status between the electrode terminals of the battery cell and the circuit breaker. If the connection status between the electrode terminals of the battery cell and the circuit breaker is abnormal, proceed to step 705; if the connection status between the electrode terminals of the battery cell and the circuit breaker is normal, proceed to step 708.

[0107] Step 705: Accumulate the number of abnormal states to obtain the number of abnormal states; if the number of abnormal states is less than the preset number, proceed to step 701; if the number of abnormal states is greater than the preset number, proceed to step 706.

[0108] Step 706: Monitor the voltage fluctuation of the battery cell; if the voltage fluctuation of the battery cell is less than a preset voltage threshold, proceed to step 701; if the voltage fluctuation of the battery cell is greater than the preset voltage threshold, proceed to step 707.

[0109] Step 707, fault warning.

[0110] Step 708, output status is normal.

[0111] 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 conflict, the various technical features mentioned in the 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 of detecting a connection state of a gasket, characterized by, The method comprises: electrochemical impedance spectroscopy (EIS) detection is performed on the battery monomer to obtain a zero-crossing point impedance of the battery monomer, wherein the zero-crossing point impedance is an impedance corresponding to a positive and negative imaginary part value switching point in the electrochemical impedance spectroscopy; an ambient temperature during the electrochemical impedance spectroscopy (EIS) detection on the battery monomer is obtained; based on the zero-crossing point impedance and the ambient temperature, a connection state of an electrode terminal of the battery monomer and the tab is determined, wherein the tab is connected to the electrode terminal of the battery monomer to connect a plurality of the battery monomers; wherein the determination of the connection state of the electrode terminal of the battery monomer and the tab based on the zero-crossing point impedance and the ambient temperature comprises: determining a first frequency based on the zero-crossing point impedance and a corresponding relationship between the zero-crossing point impedance and the frequency; determining a second frequency based on the ambient temperature and a corresponding relationship between the temperature and the frequency; determining the connection state of the electrode terminal of the battery monomer and the tab based on the first frequency and the second frequency.

2. The method of claim 1, wherein The determination of the connection state of the electrode terminal of the battery monomer and the tab based on the zero-crossing point impedance and the ambient temperature comprises: correcting the zero-crossing point impedance according to the ambient temperature to obtain a corrected impedance; determining the connection state of the electrode terminal of the battery monomer and the tab based on the corrected impedance and a preset impedance.

3. The method of claim 1 or 2, wherein The method further comprises: in response to the connection state of the electrode terminal of the battery monomer and the tab being an abnormal state, accumulating a number of times of the abnormal state to obtain an abnormal number of times; in response to the abnormal number of times being greater than a preset number of times, monitoring a voltage fluctuation of the battery monomer; based on the voltage fluctuation of the battery monomer, determining whether to perform a fault warning.

4. The method of claim 3, wherein The method further comprises: in response to the abnormal number of times being less than the preset number of times, re-performing the connection state detection of the tab on the battery monomer.

5. The method of claim 3, wherein The method further comprises: in response to the voltage fluctuation of the battery monomer being less than a preset voltage threshold, re-performing the connection state detection of the tab on the battery monomer.

6. A battery management system, characterized by, The method comprises: an EIS detection circuit configured to perform EIS detection on a battery monomer; a controller in communication connection with the EIS detection circuit, the controller being configured to perform the connection state detection method of the tab according to any one of claims 1 to 5.

7. A battery device characterized by comprising: The method comprises: a battery; and The battery management system according to claim 6.

8. An electrical device, characterized by The battery device according to claim 7.

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