Battery heating film detection method, device, equipment, storage medium and program product

Abstract

The application provides a battery heating film detection method, device, equipment, storage medium and program product, and belongs to the technical field of batteries. The battery heating film detection method provided by the application comprises the following steps: acquiring a first current of a heating loop in which a battery heating film is located and a first voltage across the battery heating film under a charging and heating condition; determining a reference resistance value of the battery heating film according to the first current and the first voltage; acquiring a second current of the heating loop in which the battery heating film is located and a second voltage across the battery heating film under a heating condition; determining a real-time resistance value of the battery heating film according to the second current and the second voltage; and determining a detection result of the battery heating film based on at least a difference between the real-time resistance value and the reference resistance value. In this way, the influence of current fluctuation can be reduced, and the detection accuracy is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a method, apparatus, equipment, storage medium, and program product for detecting battery heating films. Background Technology

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development.

[0003] In low-temperature environments, battery performance is significantly affected. As an important auxiliary device for improving battery performance in low-temperature environments, the proper functioning of the heating film is crucial for maintaining the battery temperature within a reasonable range. Therefore, how to detect whether the battery heating film is faulty is an urgent problem to be solved. Summary of the Invention

[0004] This application aims to at least address one of the technical problems existing in the background art. Therefore, one objective of this application is to provide a method, apparatus, device, storage medium, and program product for detecting battery heating films, thereby achieving the detection of battery heating films and improving detection accuracy and efficiency.

[0005] An embodiment of the first aspect of this application provides a method for detecting a battery heating film. The method includes: acquiring a first current and a first voltage across the battery heating film in a heating circuit under a charging heating condition; determining a reference resistance value of the battery heating film based on the first current and the first voltage; wherein the charging heating condition is a condition in which the battery heating film heats a battery in a charging state; acquiring a second current and a second voltage across the battery heating film in a heating circuit under a heating condition; determining a real-time resistance value of the battery heating film based on the second current and the second voltage; wherein the heating condition is a condition in which the battery heating film heats a battery; and determining a detection result of the battery heating film based at least on the difference between the real-time resistance value and the reference resistance value.

[0006] In the technical solution of this application embodiment, the detection results of the battery heating film are confirmed based on the real-time resistance value and the reference resistance value, which helps to reduce the impact of current or voltage fluctuations on the detection process and thus improve the accuracy of the detection results. In addition, the reference resistance value is determined under the charging heating condition, which helps to improve the accuracy of the reference resistance value, while the real-time resistance value is determined under any heating condition, which helps to more comprehensively evaluate the condition of the battery heating film, thereby improving the comprehensiveness and reliability of the battery heating film detection.

[0007] In some embodiments, a first current and a first voltage across the battery heating film are acquired in the heating circuit where the battery heating film is located under a charging heating condition. A reference resistance value for the battery heating film is determined based on the first current and the first voltage. The charging heating condition is the condition in which the battery heating film heats the battery in a charging state. This includes: acquiring N sets of sampling parameters corresponding one-to-one with N charging heating conditions, each sampling parameter set including at least one pair of first sampling parameters, each pair including a first current and a first voltage corresponding to the same time point; determining N first sampling resistance values ​​based on the N sets of sampling parameters; and determining the average value of the N first sampling resistance values ​​as the reference resistance value in response to the absolute value of the difference between each of the N first sampling resistance values ​​and the initial resistance value being less than or equal to a first threshold value; wherein N is a positive integer greater than 1. Therefore, by acquiring multiple first sampling resistance values ​​and confirming the reference resistance value based on the average value of the first sampling resistance values, it is beneficial to eliminate randomness and reduce the influence of abnormal resistance values ​​on the confirmation of the reference resistance value. Furthermore, the judgment between the first sampling resistance value and the initial resistance value helps to further reduce the influence of abnormal resistance on the abnormal diagnosis of the battery heating film, improving the accuracy and efficiency of the diagnosis.

[0008] In some embodiments, N sets of sampling parameter groups corresponding one-to-one with N charging and heating conditions are obtained. Each sampling parameter group includes at least one pair of first sampling parameter pairs, each pair including a first current and a first voltage corresponding to the same time point. This includes: for each charging and heating condition, obtaining M pairs of first sampling parameter pairs corresponding to M sampling time points; determining M second sampling resistance values ​​based on the M pairs of first sampling parameter pairs; and determining the first sampling parameter pairs corresponding to the m second sampling resistance values ​​as the sampling parameter group corresponding to the charging and heating condition, in response to at least m of the M second sampling resistance values ​​having an absolute value less than or equal to the initial resistance value. The initial resistance value is a resistance value determined based on the rated resistance of the battery heating film, and M and m are both positive integers, satisfying: M > 1, M / 2 ≤ m ≤ M. Determining the second sampling resistance value based on multiple pairs of first sampling parameter pairs at multiple sampling time points, and further determining the reference resistance value, is beneficial for improving the accuracy of the reference resistance value and enhancing the anti-interference capability of the diagnostic method.

[0009] In some embodiments, the time interval between the sampling time point corresponding to any pair of first sampling parameters and the start time point of the charging and heating condition is greater than or equal to a first preset duration. By setting the first preset duration, it is beneficial to improve the sampling accuracy of the first sampling parameter pair, reduce the impact of internal software delay response on diagnosis in the management system, and thus improve the effectiveness of the diagnostic results.

[0010] In some embodiments, a second current in the heating circuit where the battery heating film is located and a second voltage across the battery heating film are obtained under heating conditions. The real-time resistance value of the battery heating film is determined based on the second current and the second voltage. The heating condition is the condition where the battery heating film heats the battery. The method includes: in response to the heating circuit where the battery heating film is located being connected to a power source, acquiring P pairs of second sampling parameter pairs corresponding to different sampling time points under the heating condition. Each pair of second sampling parameter pairs includes the real-time current value of the heating circuit where the battery heating film is located and the real-time voltage value across the battery heating film. P third sampling resistance values ​​are determined based on the P pairs of second sampling parameters. The average value of the P third sampling resistance values ​​is determined as the real-time resistance value. Here, P is a positive integer greater than 1. Determining the third sampling resistance value based on multiple pairs of second sampling parameter pairs at multiple sampling time points, and further determining the real-time resistance value, helps eliminate random errors, improves the accuracy of real-time resistance value sampling, and enhances the anti-interference and reliability of the diagnostic method.

[0011] In some embodiments, the time interval between the sampling time point corresponding to any pair of second sampling parameters and the start time point of the heating condition is greater than or equal to a second preset duration. By setting a second preset duration, it is beneficial to improve the sampling accuracy of the second sampling parameter pair, reduce the impact of internal software delay response on diagnosis in the management system, and thus improve the reliability of the diagnostic results.

[0012] In some embodiments, determining the detection result of the battery heating film based on the difference between the real-time resistance value and the reference resistance value includes: determining the detection result as abnormal in response to the absolute value of the difference between the real-time resistance value and the reference resistance value being greater than or equal to a third threshold; wherein the third threshold is determined based on the reference resistance value. Using the absolute value of the difference between the real-time resistance value and the reference resistance value being greater than or equal to a third threshold to determine the detection result allows for more intuitive fault detection, thereby improving diagnostic efficiency.

[0013] In some embodiments, a first current in the heating circuit where the battery heating film is located and a first voltage across the battery heating film are obtained under charging and heating conditions. A reference resistance value of the battery heating film is determined based on the first current and the first voltage. The charging and heating condition is a condition in which the battery heating film heats the battery in a charging state, including:

[0014] Obtain N sets of sampling parameters corresponding to N charging and heating conditions. Each sampling parameter set includes at least one pair of first sampling parameters, which includes a first current and a first voltage corresponding to the same time point. Based on the N sets of sampling parameters, determine N first sampling resistance values. In response to the absolute value of the difference between each of the N first sampling resistance values ​​and the initial resistance value being less than or equal to a first threshold, determine the average value of the N first sampling resistance values ​​as the reference resistance value.

[0015] Furthermore, the detection result of the battery heating film is determined based at least on the difference between the real-time resistance value and the reference resistance value, including: determining the impedance variance based on P third sampled resistance values ​​and the real-time resistance value; and determining the detection result as abnormal in response to the impedance variance being greater than a fourth threshold; wherein the fourth threshold is determined based on N first sampled resistance values ​​and the reference resistance value.

[0016] Therefore, judging whether the battery heating film is abnormal based on the relationship between impedance variance and the fourth threshold is beneficial to reducing the impact of current or voltage fluctuations on the detection process and thus improving the accuracy of the detection results.

[0017] An embodiment of the second aspect of this application provides a detection device for a battery heating film. The device includes a first acquisition module, a second acquisition module, and a third acquisition module. The first acquisition module is configured to acquire a first current in the heating circuit where the battery heating film is located and a first voltage across the battery heating film under a charging heating condition, and determine a reference resistance value of the battery heating film based on the first current and the first voltage. The charging heating condition is the condition where the battery heating film heats the battery in a charging state. The second acquisition module is configured to acquire a second current in the heating circuit where the battery heating film is located and a second voltage across the battery heating film under a heating condition, and determine a real-time resistance value of the battery heating film based on the second current and the second voltage. The heating condition is the condition where the battery heating film heats the battery. A processing module is configured to determine the detection result of the battery heating film based at least on the real-time resistance value and the reference resistance value.

[0018] An embodiment of the third aspect of this application provides a battery device, including a battery pack, a battery heating film, a detection unit, and a controller; the battery heating film is connected to the battery pack via a heating switch; the detection unit includes a current detection element and a voltage detection element, the current detection element being connected in series with the heating unit to detect the current flowing through the heating unit, and the voltage detection element being used to detect the voltage across the heating unit; the controller is signal-connected to the detection unit, and the controller is configured to execute the detection method of the battery heating film as described in the foregoing embodiment.

[0019] An embodiment of the fourth aspect of this application provides an electrical device that includes the battery device described in the above embodiments.

[0020] An embodiment of the fifth aspect of this application provides a computing device including at least one processor; and at least one memory communicatively connected to the at least one processor, the at least one memory storing instructions that, when executed individually or jointly by the at least one processor, cause the computing device to perform the methods as described in the foregoing embodiments.

[0021] An embodiment of the sixth aspect of this application provides a computer-readable storage medium storing instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the methods as described in the foregoing embodiments.

[0022] An embodiment of the seventh aspect of this application provides a computer program product including instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the methods as described in the foregoing embodiments.

[0023] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0024] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0025] Figure 1 This is a schematic diagram of the vehicle structure according to some embodiments of this application;

[0026] Figure 2 This is an exploded structural diagram of a battery according to some embodiments of this application;

[0027] Figure 3 This is one of the flowcharts of a method for detecting a battery heating film according to some embodiments of this application;

[0028] Figure 4 This is a flowchart illustrating the determination of a reference resistor value in some embodiments of this application;

[0029] Figure 5 This is a second flowchart of a method for detecting a battery heating film according to some embodiments of this application;

[0030] Figure 6 This is a flowchart illustrating the determination of real-time resistance values ​​in some embodiments of this application;

[0031] Figure 7 This is a schematic diagram of a detection device for a battery heating film according to some embodiments of this application.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1000 vehicles;

[0034] Battery 100, controller 200, motor 300;

[0035] Box 10, Part 11, Part 2 12;

[0036] 20 battery cells;

[0037] The battery heating film detection device 400 includes a first acquisition module 410, a second acquisition module 420, and a processing module 430. Detailed Implementation

[0038] 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.

[0039] 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.

[0040] 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, unless otherwise explicitly defined.

[0041] 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.

[0042] 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.

[0043] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0044] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0045] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0046] Currently, judging from market trends, the application of power batteries is becoming increasingly widespread. Power batteries are not only used in energy storage 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, as well as in military equipment and aerospace. With the continuous expansion of power battery applications, market demand is also constantly increasing.

[0047] In low-temperature environments, battery performance is significantly affected, including but not limited to charge / discharge efficiency and capacity degradation. Furthermore, frequent charging and discharging in low-temperature environments can cause irreversible damage to the battery, thus reducing its lifespan. In some cases, when batteries are used in electric vehicles, if the battery temperature is too low, the vehicle may not be able to start.

[0048] As an important auxiliary device for improving the low-temperature performance of batteries, heating films can stabilize the battery temperature within a reasonable range. From the perspective of battery output power, a reasonable temperature range helps the battery chemical reaction to be more complete, thus maintaining stable output power. From the perspective of battery lifespan, lithium dendrites are prone to form on the negative electrode of the battery in low-temperature environments, and the heating effect of the heating film can effectively alleviate this situation. In addition, as one of the mainstream heating strategies for power battery thermal management, the heating film is managed and controlled by the battery management system. Through the interaction and feedback between the battery management system and the heating film, refined management of the battery can be achieved, thereby enabling the battery to operate within a stable and safe temperature range.

[0049] Diagnosing heating film faults is crucial for improving equipment reliability and protecting battery safety. Heating film faults include electrical faults, physical damage faults, performance degradation faults, overheating faults, and moisture faults. During the operation of the heating film, the aforementioned faults can affect its performance and effectiveness, resulting in less than expected heating results, or even damage to the heating film, potentially leading to battery safety accidents. Furthermore, heating film faults can interfere with the electrical system and affect the normal operation of other electronic components.

[0050] In some cases, heating films can be diagnosed by detecting the current in the battery heating film circuit and the temperature of the heating film and its surroundings. However, this detection method has lag, low accuracy, and weak anti-interference capabilities. Based on these considerations, this application provides a method, apparatus, device, storage medium, and program product for detecting battery heating films. The method for detecting battery heating films provided in this application includes: acquiring a first current in the heating circuit where the battery heating film is located and a first voltage across the battery heating film under charging heating conditions; determining a reference resistance value of the battery heating film based on the first current and the first voltage; the charging heating condition being the condition where the battery heating film heats a battery in a charging state; acquiring a second current in the heating circuit where the battery heating film is located and a second voltage across the battery heating film under heating conditions; determining a real-time resistance value of the battery heating film based on the second current and the second voltage; the heating condition being the condition where the battery heating film heats the battery; and determining the detection result of the battery heating film based at least on the real-time resistance value and the reference resistance value. This can reduce the influence of current fluctuations, thereby improving detection accuracy and efficiency.

[0051] The battery heating film detection method disclosed in this application can be used to diagnose batteries. The batteries disclosed in this application can be used, but are not limited to, in electrical devices such as vehicles, ships, or aircraft.

[0052] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0053] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0054] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a vehicle provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid electric vehicle, or a range-extended electric vehicle, etc. A battery 100 is disposed inside the vehicle 1000, and the battery 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery 100 can be used to power the vehicle 1000; for example, the battery 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0055] In some embodiments of this application, the battery 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0056] Please refer to Figure 2 , Figure 2This is an exploded structural diagram of a battery provided in some embodiments of this application. The battery 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, jointly defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 jointly define the space. Alternatively, the first portion 11 and the second portion 12 may both be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0057] In battery 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed manner. A mixed connection means that multiple battery cells 20 are connected in both series and parallel configurations. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed manner, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, battery 100 can also be composed of multiple battery cells 20 first connected in series, parallel, or in a mixed manner to form a battery module, and then multiple battery modules are connected in series, parallel, or in a mixed manner to form a whole, which is also housed within the housing 10. Battery 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0058] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0059] This application provides a method for detecting battery heating films, such as... Figure 3 For example, the method includes:

[0060] S110. Obtain the first current and the first voltage across the battery heating film in the heating circuit under the charging heating condition. Determine the reference resistance value of the battery heating film based on the first current and the first voltage. The charging heating condition is the condition in which the battery heating film heats the battery in the charging state.

[0061] S120. Obtain the second current and the second voltage across the battery heating film in the heating circuit under heating conditions, and determine the real-time resistance value of the battery heating film based on the second current and the second voltage; the heating condition is the condition in which the battery heating film heats the battery.

[0062] S130. The test results of the battery heating film are determined based at least on the difference between the real-time resistance value and the reference resistance value.

[0063] Heating conditions can include any condition that heats the battery, such as charging heating conditions, discharging heating conditions, and preheating conditions. Taking a battery-equipped vehicle as an example, the charging heating condition addresses the situation where the battery is heated simultaneously while being charged, the discharging heating condition addresses the situation where the battery is heated while the vehicle is running and discharging externally, and the preheating condition is the situation where the battery is preheated before it begins to officially charge or discharge.

[0064] The heating process of the battery heating film under charging heating conditions is as follows: Before charging begins, the battery charging system communicates with the Battery Management System (BMS) and monitors the battery temperature. If the battery temperature is too low, the BMS activates the battery heating film for preheating. During heating, the heat reduces the viscosity of the electrolyte inside the battery, allowing ions to move more smoothly, thus creating favorable conditions for charging. Charging only officially begins once the battery temperature reaches the appropriate charging temperature range. Furthermore, during charging, the BMS continuously monitors the battery temperature and adjusts the working state of the battery heating film accordingly to ensure the battery temperature remains within a suitable range throughout the charging process.

[0065] The preheating process is as follows: When the vehicle is stationary and ready to start, the BMS detects the battery temperature. If the temperature is below a set threshold (e.g., for lithium-ion batteries, the temperature may be below 0°C), the BMS activates the battery heating film to gradually raise the battery temperature until it reaches a suitable starting range (generally around 15-35°C) before normal startup. The in-vehicle heating process during discharge is as follows: While the vehicle is in motion, the BMS monitors the battery's temperature, current, voltage, and other parameters in real time. If the battery temperature is not within a suitable range, the BMS dynamically adjusts the heating power of the battery heating film to bring the battery temperature to a suitable range.

[0066] In S110, the battery heating film is connected to the positive and negative terminals of the battery via a heating relay to form a heating circuit. In some embodiments, there can be multiple battery heating films, which can be connected to the battery in parallel. In this case, the branch where each battery heating film is located constitutes a heating circuit. The first current can be obtained by a current sensing unit in the branch where the battery heating film is located. The first voltage can be detected by an external voltage detection device or voltage detection circuit by detecting the voltage across the battery heating film. The reference resistance value is confirmed based on the first current and the first voltage, where the first current and the first voltage are the current and voltage values ​​when the battery is in the charging and heating state. During charging, the battery is charged by a relatively stable voltage and current provided by an external power source. Under this condition, the voltage and current changes are relatively predictable and stable. Moreover, under the charging and heating condition, the battery is in a state that is closer to the actual use scenario. The test results can more accurately reflect the electrical characteristics of the battery during the actual charging and heating process, and the calculated resistance value is more meaningful. In contrast, under the discharging and heating condition, the voltage and current will fluctuate with the load and the depth of discharge. This instability will bring a large error to the resistance test, thus affecting the accuracy of the reference resistance value. Under the preheating condition, the battery is not charged or discharged, and the test results are difficult to reflect the actual working state of the battery heating film.

[0067] In S120, the detection of the second current and the second voltage can be performed using the same method as in S110. It's important to understand that the second current and second voltage can be acquired under any heating condition. Because battery usage scenarios are very complex, in addition to charging heating conditions, they may be under various other heating conditions, such as discharging heating during driving, or preheating after prolonged parking in low-temperature environments. By detecting the real-time resistance value under any heating condition and comparing it with a reference resistance value, more practical usage scenarios can be covered, thus enabling comprehensive and accurate monitoring of the battery heating film's operating status and timely detection of heating film faults.

[0068] In S130, the detection result of the battery heating film can be determined based on the difference between the real-time resistance value and the reference resistance value. The detection result can indicate a fault or that the heating circuit is functioning normally. When the battery heating film is working normally, theoretically, the real-time resistance value and the reference resistance value should be essentially the same, without significant difference. However, when the battery heating film malfunctions, it will cause an increase in resistance or abnormal fluctuations in resistance in the circuit, resulting in a significant difference between the real-time resistance value and the reference resistance value. Therefore, the detection result of the battery heating film can be determined by the difference between the real-time resistance value and the reference resistance value.

[0069] Confirming the test results of the battery heating film based on real-time resistance values ​​and reference resistance values ​​helps reduce the impact of current or voltage fluctuations on the testing process, thereby improving the accuracy of the test results. In addition, the reference resistance value is determined under charging and heating conditions, which helps improve the accuracy of the reference resistance value, while the real-time resistance value is determined under any heating conditions, which helps to more comprehensively evaluate the fault status of the battery heating film, thereby improving the comprehensiveness and reliability of the battery heating film test.

[0070] According to some embodiments of this application, such as Figure 4 For example, S110: Obtain the first current and the first voltage across the battery heating film in the heating circuit under charging and heating conditions; determine the reference resistance value of the battery heating film based on the first current and the first voltage; the charging and heating condition is the condition in which the battery heating film heats the battery in a charging state, including:

[0071] S111. Obtain N sets of sampling parameters that correspond one-to-one with N charging and heating conditions. Each set of sampling parameters includes at least one pair of first sampling parameters, and each pair of first sampling parameters includes a first current and a first voltage corresponding to the same time point.

[0072] S112. Determine N first sampling resistor values ​​based on N sets of sampling parameters;

[0073] S113. In response to the absolute value of the difference between each of the N first sampled resistor values ​​and the initial resistor value being less than or equal to a first threshold, the average value of the N first sampled resistor values ​​is determined as the reference resistor value; where N is a positive integer greater than 1.

[0074] The N sets of sampling parameters can be obtained by sampling and detecting under N independent charging and heating conditions. In some embodiments, the battery can enter multiple independent charging and heating conditions by repeatedly opening and closing the heating positive relay and the heating negative relay. For each charging and heating condition, the heating positive relay and the heating negative relay can be closed while the battery is charging. At this time, the heating circuit is connected to the power supply and the battery is heated, thereby causing the battery to enter the charging and heating condition. Under this condition, at least one set of first current and first voltage are detected. In this way, N sets of sampling parameters are obtained, and N first sampling resistance values ​​are calculated respectively. In some implementations, the value of N can be 2, 3, 4, 5, or 6, etc.

[0075] S113 verifies each first sampled resistor value to prevent abnormal results caused by other accidental factors from affecting the determination of the reference resistor value.

[0076] The initial resistance value is the rated resistance value of the battery heating film, which is a standard reference value given by the battery heating film manufacturer based on normal and stable operating environment and conditions for the product's resistance characteristics. The value of the first threshold can be determined based on the initial resistance value, for example, it can be proportional to the initial resistance value, where the proportion range can be 10%-20%.

[0077] By acquiring multiple first-sample resistance values ​​and confirming the reference resistance value based on the average of these first-sample resistance values, randomness can be eliminated, and the impact of abnormal resistance values ​​on the confirmation of the reference resistance value can be reduced. Furthermore, comparing the first-sample resistance values ​​with the initial resistance value helps to further reduce the impact of abnormal resistance on the diagnosis of battery heating film anomalies, improving the accuracy and efficiency of the diagnosis.

[0078] According to some embodiments of this application, N sets of sampling parameters corresponding to N charging and heating conditions are obtained. Each sampling parameter set includes at least one pair of first sampling parameters, and each first sampling parameter pair includes a first current and a first voltage corresponding to the same time point. The method includes: for each charging and heating condition, obtaining M pairs of first sampling parameters corresponding to M sampling time points respectively; determining M second sampling resistance values ​​based on the M pairs of first sampling parameter pairs; in response to at least m of the M second sampling resistance values ​​having an absolute value less than or equal to the initial resistance value, determining the first sampling parameter pairs corresponding to the m second sampling resistance values ​​as the sampling parameter set corresponding to the charging and heating condition; wherein the initial resistance value is a resistance value determined based on the rated resistance of the battery heating film, M and m are both positive integers, and satisfy: M > 1, M / 2 ≤ m ≤ M.

[0079] Sampling time points refer to the points in time when the battery heating film is sampled. Each sampling time point can sample the current flowing through the battery heating film and the voltage across the film. For each charging and heating condition, M pairs of first sampling parameters are obtained by sampling at M sampling time points, which can be determined according to a preset sampling frequency. In some embodiments, the interval between any two adjacent sampling time points is T, meaning that a pair of first sampling parameters is acquired every T interval, resulting in M ​​consecutive pairs of first sampling parameters. Each pair of first sampling parameters includes a first current and a first voltage corresponding to the same sampling time point. The second sampling resistance value R 2-M The first current I in the first sampling parameter pair at the corresponding time point 2-M and the first voltage U 2-M The calculation method is as follows: The interval T can range from 5 milliseconds (ms) to 20 milliseconds (ms), specifically 5ms, 8ms, 10ms, 15ms or 20ms.

[0080] In other embodiments, the interval between two adjacent sampling points may not be a fixed value, which can increase randomness and thus obtain more realistic and accurate detection results. For example, the interval between the first and second sampling points may be 5 milliseconds, and the interval between the second and third sampling points may be 10 milliseconds, etc., which will not be listed here.

[0081] For each of the M second sampling resistor values, a validity check is required. If at least half of the M second sampling resistor values ​​are valid, then the first sampling parameter pair corresponding to these m valid second sampling resistor values ​​can be used to determine the sampling parameter group corresponding to the charging heating condition. Otherwise, sampling needs to be continuously performed to update the first sampling parameter pair until at least m of the M consecutive first sampling parameter pairs have valid calculated second sampling resistor values.

[0082] The value of the second threshold can be determined based on the initial resistance value. In some embodiments, the second threshold can be a certain proportion of the initial resistance value R. 初始 For example, 10%-20% R 初始 Specifically, the threshold can be 10%, 12%, 15%, 18%, or 20%. The second threshold can be the same as or different from the first threshold.

[0083] like Figure 5 As shown, with N=5, T=10 milliseconds (ms), M=16, the first and second thresholds are the same and both are taken as 15%R. 初始 Taking an example, this application describes a method for detecting a battery heating film according to one embodiment.

[0084] First, for each charging and heating condition, 16 pairs of first sampling parameters are obtained at 10-millisecond intervals, corresponding to 16 sampling time points. Then, based on these 16 pairs of first sampling parameters, 16 second sampling resistance values ​​are determined, namely R... 2-1 R 2-2 , ..., R 2-16 .

[0085] Secondly, the validity of the 16 second sampling resistor values ​​is determined. For example, for the nth second sampling resistor value R... 2-n Calculate its relationship with the initial resistance R. 初始 The absolute value of the difference is calculated and compared with a second threshold. If the comparison result satisfies the formula: -R 初始 ≤15%R 初始 Then the nth second sampling resistor value R is determined to be... 2-nValid. If at least m (m≥8) of the 16 second sampling resistor values ​​are valid, the first sampling parameter pairs corresponding to the m second sampling resistor values ​​are determined as the sampling parameter group corresponding to the charging heating condition, and the first sampling resistor of the sampling parameter group is calculated. In some embodiments, the first sampling resistor value is obtained by averaging the m second sampling resistor values.

[0086] Repeat the steps described above to obtain the first sampling resistance value, and obtain the five first sampling resistance values ​​corresponding to the five charging and heating conditions, i.e., R. 1-1 R 1-2 , ..., R 1-5 .

[0087] Next, the validity of the five first-sample resistor values ​​is determined. The validity is determined when the absolute value of the difference between each of the five first-sample resistor values ​​and the initial resistance value is less than or equal to the initial resistance R. 初始 If 15% of the value is positive, it is considered valid. That is, the first sampling resistor value R of the nth time. 1-n Satisfying the expression |R 1-n -R 初始 ≤15%R 初始 Where 1 ≤ n ≤ 5. If there exists a first sampling resistor value R 1-n If the expression is not satisfied, the value will be discarded and the steps to obtain the first sampling resistor value will be repeated until five valid first sampling resistor values ​​are obtained.

[0088] Finally, the average of the five valid first sampling resistor values ​​is calculated and determined as the reference resistor value.

[0089] Determining the second sampling resistance value based on multiple pairs of first sampling parameters at multiple sampling time points, and further determining the reference resistance value, is beneficial to improving the accuracy of the reference resistance value and enhancing the anti-interference capability of the diagnostic method.

[0090] According to some embodiments of this application, the time interval between the sampling time point corresponding to any pair of first sampling parameters and the start time point of the charging and heating condition is greater than or equal to a first preset duration.

[0091] In some embodiments, the first preset duration is also the response duration. The BMS issues a control command to close the heating positive relay and the heating negative relay, thereby energizing the heating circuit. This process has a certain delay; that is, it takes a certain amount of time from the issuance of the control command to the battery and the battery heating film fully entering the normal state of charging and heating. During this time, the operation of the circuit components is not yet stable, and sampling at this time cannot accurately reflect the true situation of the battery heating film. Therefore, sampling needs to avoid this time period. The value of the first preset duration can be selected according to factors such as the specifications and characteristics of the circuit components. In some embodiments, the first preset duration can be 80ms-120ms, specifically 80ms, 90ms, 100ms, 110ms, and 120ms.

[0092] Setting a first preset duration helps improve the sampling accuracy of the first sampling parameter pair, reduces the impact of internal software delays on diagnosis in the management system, and thus improves the effectiveness of the diagnostic results.

[0093] According to some embodiments of this application, such as Figure 6 As shown, S120 includes:

[0094] S121. In response to the connection between the heating circuit where the battery heating film is located and the power supply, obtain P pairs of second sampling parameters corresponding to different sampling time points under the heating condition. Each pair of second sampling parameters includes the real-time current value of the heating circuit where the battery heating film is located and the real-time voltage value at both ends of the battery heating film.

[0095] S122. Determine P third sampling resistor values ​​based on the P groups of second sampling parameters;

[0096] S123. The average value of P third-sampled resistor values ​​is determined as the real-time resistance value; where P is a positive integer greater than 1.

[0097] For each heating condition, P can acquire the second sampling parameter pair on a time-based basis. In some embodiments, the period for acquiring the second sampling parameter pair is t, that is, after acquiring one pair of second sampling parameter pairs, another pair of second sampling parameter pairs is acquired after t. Each pair of second sampling parameter pairs includes the real-time current value of the heating circuit where the battery heating film is located and the real-time voltage value across the battery heating film, i.e., the second current and the second voltage. The third sampling resistance value R at a specific time point... 3-P The first current I in the first sampling parameter pair at the corresponding time point 3-P and the first voltage U 3-P The calculation method is as follows:

[0098] like Figure 5As shown, a method for detecting a battery heating film according to an embodiment of this application is described with t = 10 ms and M = P = 16. First, for each heating condition, 16 pairs of second sampling parameters corresponding to 16 sampling time points are obtained, wherein the time period between the 16 sampling time points is 10 ms. Then, based on the 16 pairs of second sampling parameters, 16 third sampling resistance values ​​are determined, and the real-time resistance value is obtained by averaging the 16 third sampling resistance values.

[0099] Using multiple pairs of second sampling parameters at multiple sampling time points to determine the third sampling resistance value, and further to determine the real-time resistance value, helps to eliminate random errors, improve the accuracy of real-time resistance value sampling, and enhance the anti-interference and reliability of the diagnostic method.

[0100] According to some embodiments of this application, the time interval between the sampling time point corresponding to any pair of second sampling parameters and the start time point of the heating condition is greater than or equal to the second preset duration.

[0101] In some embodiments, the second preset duration can be the same as the first preset duration, wherein the first preset duration can be 80ms-120ms, specifically 80ms, 90ms, 100ms, 110ms, and 120ms. In some embodiments, 100ms after the start of the heating condition, the acquisition of the second sampling parameter pair begins, and the acquisition of the second sampling parameter pair is performed again at every time interval t.

[0102] Setting a second preset duration can improve the sampling accuracy of the second sampling parameter pair, reduce the impact of internal software delays on diagnosis in the management system, and thus improve the reliability of the diagnostic results.

[0103] According to some embodiments of this application, S130 includes: determining the detection result as abnormal in response to the absolute value of the difference between the real-time resistance value and the reference resistance value being greater than or equal to a third threshold; wherein the third threshold is determined based on the reference resistance value.

[0104] The third threshold can be determined based on the specific fault type and the specifications of the circuit components. In some embodiments, the third threshold can be determined based on the magnitude of a reference resistance value. For example, the third threshold can be proportional to the reference resistance value, wherein the third threshold can be 10%-20% of the reference resistance value, specifically 10%, 12%, 15%, or 20%. Figure 5 As shown, taking the third threshold as an example with a 15% ratio to the initial resistance value, if the real-time resistance value R... 实时 With reference resistance value R 基准 Satisfying the expression |R 实时 -R 基准 |≥15%R基准 If the result is negative, the test result is abnormal; otherwise, the test result is normal.

[0105] Because the magnitude of current is affected by many factors, relying solely on current anomalies is insufficient for accurate fault detection of battery heating films. This application's embodiment calculates the resistance value using the detected current and voltage values, and determines the more accurate detection result based on the difference between the resistance value and a reference resistance value. For example, it can be used to detect arcing faults in battery heating films. Arcing is a relatively unique phenomenon in electrical equipment, usually caused by decreased insulation performance within the heating film, the presence of gaps, or conductive impurities, leading to current flowing through a path that should not be conductive, forming an electric arc discharge. In the initial stage of arcing, it's equivalent to adding a new, much smaller discharge path (the arc itself has very low resistance) in parallel with the existing normal heating film resistance circuit. According to the characteristics of parallel circuits, the total resistance will decrease. Under the condition that the supply voltage remains unchanged, according to Ohm's law, the total current of the circuit will increase. At this time, the supply voltage across the heating film remains unchanged for a short period of time. Therefore, the real-time resistance value can be calculated by detecting the voltage and current values. The difference between the real-time resistance value and the reference resistance value can be used to determine whether the battery heating film has an arcing fault. Specifically, if the absolute value of the difference between the real-time resistance value and the reference resistance value is greater than or equal to the third threshold, the detection result can be determined as an arcing fault of the battery heating film.

[0106] By determining the detection result based on the absolute value of the difference between the real-time resistance value and the reference resistance value being greater than or equal to the third threshold, fault detection can be performed more intuitively, thereby improving diagnostic efficiency.

[0107] According to some embodiments of this application, S110 includes:

[0108] Obtain N sets of sampling parameters corresponding to N charging and heating conditions. Each sampling parameter set includes at least one pair of first sampling parameters, which includes a first current and a first voltage corresponding to the same time point. Based on the N sets of sampling parameters, determine N first sampling resistance values. In response to the absolute value of the difference between each of the N first sampling resistance values ​​and the initial resistance value being less than or equal to a first threshold, determine the average value of the N first sampling resistance values ​​as the reference resistance value.

[0109] Furthermore, S130 includes: determining the impedance variance based on P third sampled resistor values ​​and real-time resistor values; and determining the detection result as abnormal in response to the impedance variance being greater than a fourth threshold; wherein the fourth threshold is determined based on N first sampled resistor values ​​and a reference resistor value.

[0110] The impedance variance σ is determined by the third sampling resistor value R. 3-P and real-time resistance value R 实时In some embodiments, the average of P third-sampled resistor values ​​is determined as the real-time resistance value R. 实时 And the impedance variance σ satisfies the expression

[0111]

[0112] Different fault types correspond to different fluctuations in real-time resistance values, and the fourth threshold can be determined based on the specific fault type. In some embodiments, the fourth threshold can be determined based on the variance of multiple first sampled resistance values; in other embodiments, the fourth threshold can also be determined based on the variance of multiple second sampled resistance values ​​of the first sampled resistance values.

[0113] In some embodiments, S130 may combine the method of determining the difference between the real-time resistance value and the reference resistance value with the method of determining the impedance variance. For example, S130 includes: in response to the absolute value of the difference between the real-time resistance value and the reference resistance value being less than a third threshold, determining the impedance variance based on P third sampled resistance values ​​and the real-time resistance value; in response to the impedance variance being greater than a fourth threshold, determining the detection result as abnormal.

[0114] This application embodiment can be used to detect arcing faults in battery heating films. This is because when an arcing fault occurs in the battery heating film, the current value in the heating circuit will increase rapidly in a short period of time. However, as the arcing situation develops, the battery heating film may experience a partial open circuit, which may cause the current to suddenly drop to 0 or fluctuate violently. The corresponding calculated real-time resistance value will fluctuate abnormally. By calculating the impedance variance of the real-time resistance value relative to the reference resistance value, it is possible to more accurately determine whether the battery heating film has an arcing fault. Specifically, in response to the impedance variance being greater than a set fourth threshold, the detection result can be determined as an arcing fault in the battery heating film.

[0115] Using the relationship between impedance variance and the fourth threshold to determine whether the battery heating film is abnormal helps to reduce the impact of current or voltage fluctuations on the detection process, thereby improving the accuracy of the detection results.

[0116] This application provides a battery heating film detection device 400, such as... Figure 7As shown, the device includes a first acquisition module 410, a second acquisition module 420, and a processing module 430. The first acquisition module 410 is configured to acquire a first current in the heating circuit where the battery heating film is located and a first voltage across the battery heating film under charging and heating conditions, and determine a reference resistance value of the battery heating film based on the first current and the first voltage. The charging and heating condition is the condition where the battery heating film heats the battery in a charging state. The second acquisition module 420 is configured to acquire a second current in the heating circuit where the battery heating film is located and a second voltage across the battery heating film under heating conditions, and determine a real-time resistance value of the battery heating film based on the second current and the second voltage. The heating condition is the condition where the battery heating film heats the battery. The processing module 430 is configured to determine the detection result of the battery heating film based at least on the real-time resistance value and the reference resistance value.

[0117] The first acquisition module 410 and the second acquisition module 420 can be a current sensing unit in the branch where the battery heating film is located, and a module that can detect the voltage across the battery heating film via an external voltage detection device. The first acquisition module 410 and the second acquisition module 420 can be identical, and the processing module 430 can correspond to, for example... Figure 3 Step 130 is shown.

[0118] It should be noted that the functions of the modules discussed in this paper can be divided into multiple modules, and / or at least some functions of multiple modules can be combined into a single module. The specific actions performed by a particular module discussed in this paper include the specific module itself performing the action, or alternatively, the specific module calling or otherwise accessing another component or module that performs the action (or performs the action in conjunction with the specific module). Therefore, a specific module performing an action can include the specific module performing the action itself and / or another module that performs the action, called or otherwise accessed by the specific module. The relevant beneficial effects have been described above and will not be repeated here.

[0119] This application provides a battery device including a battery pack, a battery heating film, a detection unit, and a controller. The battery heating film is connected to the battery pack via a heating switch. The detection unit includes a current detection element and a voltage detection element. The current detection element is connected in series with the heating unit to detect the current flowing through the heating unit, and the voltage detection element is used to detect the voltage across the heating unit. The controller is signal-connected to the detection unit and is configured to execute the detection method of the battery heating film as described in the foregoing embodiment.

[0120] The battery pack can be a single battery or multiple batteries connected in series or parallel. The battery pack can be connected to a heating switch; in some embodiments, the heating switch can be a relay, specifically including a positive heating relay and a negative heating relay. The current sensing element can be a current sensing unit connected in series in the battery heating circuit, and the voltage sensing element can be a voltage sensing circuit applied across the battery heating film, thereby enabling voltage detection of the battery heating film. The detection unit signal can be connected to the controller via wired or wireless means, enabling data exchange. The relevant beneficial effects have been described above and will not be repeated here.

[0121] This application provides an electrical device, including the battery device described in the foregoing embodiments.

[0122] Electrical equipment refers to equipment that converts electrical energy into other forms of energy (such as light energy, heat energy, mechanical energy, etc.). Electrical equipment including the battery device in this embodiment can be household equipment, industrial equipment, or medical equipment, such as electric water heaters, electric heaters, industrial electric furnaces, lathes, X-ray machines, or medical ultrasound equipment.

[0123] This application provides a computing device including at least one processor and at least one memory communicatively connected to the at least one processor. The at least one memory stores instructions that, when executed individually or jointly by the at least one processor, cause the computing device to perform the methods described in the foregoing embodiments.

[0124] The computing device may include at least one processor capable of communicating with each other, such as via a bus or other suitable connection, memory, communication interfaces(s), display device, other input / output (I / O) devices, and one or more mass storage devices. Instructions are stored in the memory, which, when executed by the processor, cause the processor to perform the methods described in the above embodiments.

[0125] Computing devices can be of various types. Examples of computing devices include, but are not limited to: desktop computers, server computers, laptop or netbook computers, mobile devices (e.g., tablets, cellular or other wireless phones (e.g., smartphones), notebook computers, mobile stations), wearable devices (e.g., glasses, watches), entertainment devices (e.g., entertainment appliances, set-top boxes communicatively coupled to a display device, game consoles), televisions or other display devices, automotive computers, and so on.

[0126] This application provides a computer-readable storage medium storing instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the methods as described in the foregoing embodiments.

[0127] Computer-readable storage media include volatile and non-volatile, removable and non-removable media implemented by any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Computer-readable storage media include, but are not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, DVD, or other optical storage devices, magnetic cassettes, magnetic tapes, disk storage devices or other magnetic storage devices, or any other non-transmission medium that can be used to store information for access by computer equipment.

[0128] This application provides a computer program product including instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the methods as described in the foregoing embodiments.

[0129] Combination Figures 3-6 As shown, the detection method for a battery heating film provided in this application is described below.

[0130] First, for each charging and heating condition, 16 pairs of first sampling parameters are obtained at 10-millisecond intervals, corresponding to 16 sampling time points. Then, based on these 16 pairs of first sampling parameters, 16 second sampling resistance values ​​are determined, namely R... 2-1 R 2-2 , ..., R 2-16 .

[0131] Secondly, the validity of the 16 second sampling resistor values ​​is determined. For example, for the nth second sampling resistor value R... 2-n Calculate its relationship with the initial resistance R. 初始 The absolute value of the difference is calculated and compared with a second threshold. If the comparison result satisfies the formula: |R 2-n -R 初始 ≤15%R 初始 Then the nth second sampling resistor value R is determined to be... 2-n Valid. If at least m (m≥8) of the 16 second sampling resistor values ​​are valid, the first sampling parameter pairs corresponding to the m second sampling resistor values ​​are determined as the sampling parameter group corresponding to the charging heating condition, and the first sampling resistor of the sampling parameter group is calculated. In some embodiments, the first sampling resistor value is obtained by averaging the m second sampling resistor values.

[0132] Repeat the steps described above to obtain the first sampling resistance value, and obtain the five first sampling resistance values ​​corresponding to the five charging and heating conditions, i.e., R. 1-1 R 1-2 , ..., R 1-5 .

[0133] Next, the validity of the five first-sample resistor values ​​is determined. The validity is determined when the absolute value of the difference between each of the five first-sample resistor values ​​and the initial resistance value is less than or equal to the initial resistance R. 初始 If 15% of the value is positive, it is considered valid. That is, the first sampling resistor value R of the nth time. 1-n Satisfying the expression |R 1-n -R 初始 ≤15%R 初始 Where 1 ≤ n ≤ 5. If there exists a first sampling resistor value R 1-n If the expression is not satisfied, the value will be discarded, and the steps to obtain the first sampled resistor value will be repeated until five valid first sampled resistor values ​​are obtained. The average of the five valid first sampled resistor values ​​will be calculated and determined as the reference resistor value.

[0134] Then, for each heating condition, 16 pairs of second sampling parameters corresponding to 16 sampling time points are obtained. The time interval between the sampling time point corresponding to each second sampling parameter pair and the start time point of the heating condition is set to 100ms, and the time period between the 16 sampling time points is 10ms. Then, based on the 16 pairs of second sampling parameters, 16 third sampling resistance values ​​are determined, and the real-time resistance value is obtained by averaging these 16 third sampling resistance values. If the real-time resistance value R... 实时 With reference resistance value R 基准 Satisfying the expression |R 实时 -R 基准 |≥15%R 基准 If the value is not found in the sampled resistor, the detection result is considered abnormal; otherwise, the detection result is considered normal. Alternatively, the average value of the P third-sampled resistor values ​​can be determined as the real-time resistance value R. 实时 And the impedance variance σ satisfies the expression If the impedance variance σ is greater than the fourth threshold, the detection result is abnormal. The fourth threshold can be determined based on the variance of multiple first sampling resistor values, or it can be determined based on the variance of multiple second sampling resistor values ​​of the first sampling resistor values.

[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 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 for detecting a battery heating film, characterized in that, include: The first current in the heating circuit where the battery heating film is located and the first voltage across the battery heating film are obtained under the charging and heating condition. The reference resistance value of the battery heating film is determined based on the first current and the first voltage. The charging and heating condition is the condition in which the battery heating film heats the battery in the charging state. The second current in the heating circuit where the battery heating film is located and the second voltage across the battery heating film are obtained under the heating condition. The real-time resistance value of the battery heating film is determined based on the second current and the second voltage. The heating condition is the condition under which the battery heating film heats the battery. The detection result of the battery heating film is determined based at least on the difference between the real-time resistance value and the reference resistance value.

2. The detection method according to claim 1, characterized in that, The process of obtaining the first current in the heating circuit where the battery heating film is located and the first voltage across the battery heating film under charging and heating conditions, and determining the reference resistance value of the battery heating film based on the first current and the first voltage, wherein the charging and heating conditions are conditions in which the battery heating film heats the battery in a charging state, includes: Obtain N sets of sampling parameters that correspond one-to-one with N charging and heating conditions. Each set of sampling parameters includes at least one pair of first sampling parameters, and the first pair of sampling parameters includes the first current and the first voltage corresponding to the same point in time. N first sampling resistor values ​​are determined based on N sets of sampling parameters; In response to the absolute value of the difference between each of the N first sampled resistor values ​​and the initial resistance value being less than or equal to a first threshold, the average value of the N first sampled resistor values ​​is determined as the reference resistance value; Where N is a positive integer greater than 1.

3. The detection method according to claim 2, characterized in that, Obtain N sets of sampling parameters corresponding one-to-one with N charging and heating conditions. Each set of sampling parameters includes at least one pair of first sampling parameters, and the first sampling parameter pair includes the first current and the first voltage corresponding to the same point in time. For each charging and heating condition, obtain M pairs of first sampling parameters corresponding to M sampling time points respectively; Based on M pairs of the first sampling parameters, M second sampling resistance values ​​are determined respectively; In response to the fact that at least m of the M second sampling resistor values ​​have an absolute value of difference from the initial resistance value that is less than or equal to a second threshold, the first sampling parameter pair corresponding to the m second sampling resistor values ​​is determined as the sampling parameter group corresponding to the charging heating condition; Wherein, the initial resistance value is a resistance value determined based on the rated resistance of the battery heating film, M and m are both positive integers, and satisfy: M>1, M / 2≤m≤M.

4. The detection method according to claim 3, characterized in that, The time interval between the sampling time point corresponding to any pair of the first sampling parameters and the start time point of the charging and heating condition is greater than or equal to the first preset duration.

5. The detection method according to any one of claims 1-4, characterized in that, The second current of the heating circuit where the battery heating film is located and the second voltage across the battery heating film are obtained under the heating condition, and the real-time resistance value of the battery heating film is determined based on the second current and the second voltage. The heating condition refers to the condition in which the battery heating film heats the battery, including: In response to the connection between the heating circuit where the battery heating film is located and the power supply, P pairs of second sampling parameters corresponding to different sampling time points under the heating condition are obtained. Each pair of second sampling parameters includes the real-time current value of the heating circuit where the battery heating film is located and the real-time voltage value at both ends of the battery heating film. Based on the second sampling parameters of group P, determine the P third sampling resistor values ​​respectively; The average value of the P third-sampled resistor values ​​is determined as the real-time resistance value; Where P is a positive integer greater than 1.

6. The detection method according to claim 5, characterized in that, The time interval between the sampling time point corresponding to any pair of the second sampling parameters and the start time point of the heating condition is greater than or equal to the second preset duration.

7. The detection method according to claim 5, characterized in that, The determination of the detection result of the battery heating film based at least on the difference between the real-time resistance value and the reference resistance value includes: If the absolute value of the difference between the real-time resistance value and the reference resistance value is greater than or equal to a third threshold, the detection result is determined to be abnormal. The third threshold is determined based on the reference resistance value.

8. The detection method according to claim 5, characterized in that, The process of obtaining the first current in the heating circuit where the battery heating film is located and the first voltage across the battery heating film under charging and heating conditions, and determining the reference resistance value of the battery heating film based on the first current and the first voltage, wherein the charging and heating conditions are conditions in which the battery heating film heats the battery in a charging state, includes: Obtain N sets of sampling parameters that correspond one-to-one with N charging and heating conditions. Each set of sampling parameters includes at least one pair of first sampling parameters, and the first pair of sampling parameters includes the first current and the first voltage corresponding to the same point in time. N first sampling resistor values ​​are determined based on N sets of sampling parameters; In response to the absolute value of the difference between each of the N first sampled resistor values ​​and the initial resistance value being less than or equal to a first threshold, the average value of the N first sampled resistor values ​​is determined as the reference resistance value; Furthermore, determining the detection result of the battery heating film based at least on the difference between the real-time resistance value and the reference resistance value includes: The impedance variance is determined based on P third-sampled resistor values ​​and the real-time resistor value; In response to the impedance variance being greater than a fourth threshold, the detection result is determined to be abnormal; wherein the fourth threshold is determined based on N first sampling resistor values ​​and the reference resistor value.

9. A detection device for a battery heating film, characterized in that, include The first acquisition module is configured to acquire the first current in the heating circuit where the battery heating film is located and the first voltage across the battery heating film under the charging and heating condition, and determine the reference resistance value of the battery heating film based on the first current and the first voltage. The charging and heating condition is the condition in which the battery heating film heats the battery in the charging state. The second acquisition module is configured to acquire the second current of the heating circuit where the battery heating film is located and the second voltage across the battery heating film under heating conditions, and determine the real-time resistance value of the battery heating film based on the second current and the second voltage; the heating condition is the condition in which the battery heating film heats the battery. The processing module is configured to determine the detection result of the battery heating film based at least on the real-time resistance value and the reference resistance value.

10. A battery device, characterized in that, include Battery pack, A battery heating film is connected to the battery pack via a heating switch; The detection unit includes a current detection element and a voltage detection element. The current detection element is connected in series with the heating unit to detect the current flowing through the heating unit, and the voltage detection element is used to detect the voltage across the heating unit. A controller, signal-connected to the detection unit, is configured to perform the detection method for the battery heating film as described in claims 1-8.

11. An electrical appliance, characterized in that, Includes the battery device as described in claim 10.

12. A computing device, characterized in that, include: At least one processor; as well as At least one memory communicatively connected to the at least one processor, the at least one memory storing instructions that, when executed individually or jointly by the at least one processor, cause the computing device to perform the method of any one of claims 1 to 8.

13. A computer-readable storage medium, characterized in that, The device stores instructions that, when executed individually or jointly by one or more processors of the computing device, cause the computing device to perform the method of any one of claims 1 to 8.

14. A computer program product, characterized in that, Includes instructions that, when executed individually or jointly by one or more processors of a computing device, cause the computing device to perform the method of any one of claims 1 to 8.

Images