Voltage acquisition line fault detection method and device, storage medium and electronic equipment

Abstract

The invention provides a voltage acquisition line fault detection method and device, a storage medium and electronic equipment, and relates to the field of power batteries. The method comprises the following steps: determining a suspicious battery cell with abnormal actually measured voltage from a plurality of battery cells by the electronic equipment; acquiring historical voltage information of the suspicious battery cell; and if the historical voltage information has the harmonic wave with the frequency greater than the abnormal frequency threshold, determining that the voltage acquisition line of the suspicious cell has an open-circuit fault. Therefore, accurate identification is realized by analyzing whether the historical voltage information of the suspicious battery cell has the high-frequency harmonic component or not and utilizing the specific electrical transient characteristic of the open-circuit fault, so that compared with comparison only depending on the voltage amplitude, the diagnosis accuracy and the anti-interference capability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power batteries, in particular to a voltage acquisition line fault detection method and device, a storage medium and an electronic device. BACKGROUND

[0002] In a power battery management system, accurately monitoring the voltage of each battery cell is a core link to ensure system safety and performance stability. Since a battery pack is usually composed of multiple battery cells in series, if the voltage acquisition line of any battery cell has an open circuit fault, the single battery voltage data will be lost or distorted, which will affect the accuracy of the entire battery state estimation, such as SOC (state of charge), SOH (state of health), and key functions such as equalization control. More seriously, if such a fault is not identified in time, it may cause overcharging or overdischarging risks, exacerbate thermal runaway risks, and threaten the operation safety of the vehicle or energy storage system.

[0003] The method commonly used in the industry at present is to determine whether there is an open circuit condition based on the comparison logic between voltage values. The system will collect the voltage data of each single battery in real time, and analyze it by setting a fixed threshold or a relative difference. For example, when the measured voltage of a certain battery cell deviates significantly from the voltage distribution trend of adjacent battery cells or the whole, it may be determined that the sampling line of the battery cell has an abnormality. This detection method relies on the voltage sorting, the deviation degree of the maximum and minimum values and the average value, and whether the voltage gradient between adjacent single batteries is continuous.

[0004] However, it is found in practice that this kind of diagnosis method based on pure voltage amplitude comparison has many limitations in complex working conditions and is prone to misjudgment. SUMMARY

[0005] In order to overcome at least one of the deficiencies in the prior art, the present application provides a voltage acquisition line fault detection method, device, storage medium and electronic device, comprising: In a first aspect, the present application provides a voltage acquisition line fault detection method, the method comprising: determining a suspicious battery cell with abnormal measured voltage from a plurality of battery cells; obtaining historical voltage information of the suspicious battery cell; if the historical voltage information has a harmonic with a frequency greater than an abnormal frequency threshold, determining that the voltage acquisition line of the suspicious battery cell has an open circuit fault.

[0006] In a second aspect, the present application provides a voltage acquisition line fault detection device, the device comprising: a battery cell fast screening module for determining a suspicious battery cell with abnormal measured voltage from a plurality of battery cells; a historical voltage module configured to acquire historical voltage information of the suspicious battery cell; a fault diagnosis module configured to determine that an open-circuit fault exists in the voltage acquisition line of the suspicious battery cell if the historical voltage information has a harmonic with a frequency greater than an abnormal frequency threshold.

[0007] In a third aspect, the present application provides a storage medium, which stores a computer program. When the computer program is executed by a processor, the voltage acquisition line fault detection method is implemented.

[0008] In a fourth aspect, the present application provides an electronic device, which comprises a processor and a memory. The memory stores a computer program. When the computer program is executed by the processor, the voltage acquisition line fault detection method is implemented.

[0009] Compared with the prior art, the present application has the following beneficial effects: In the voltage acquisition line fault detection method, device, storage medium and electronic device provided by the present application, the electronic device determines a suspicious battery cell with abnormal measured voltage from a plurality of battery cells; acquires historical voltage information of the suspicious battery cell; and determines that an open-circuit fault exists in the voltage acquisition line of the suspicious battery cell if the historical voltage information has a harmonic with a frequency greater than an abnormal frequency threshold. In this way, by analyzing whether there is a high-frequency harmonic component in the historical voltage information of the suspicious battery cell, the unique electrical transient characteristic of the open-circuit fault is utilized, so that accurate identification is achieved. Therefore, compared with only relying on voltage amplitude comparison, the accuracy and anti-interference ability of diagnosis are improved. BRIEF DESCRIPTION OF DRAWINGS

[0010] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0011] Figure 1 A flowchart of the voltage acquisition line fault detection method provided by the embodiments of the present application is shown in the figure. Figure 2 A connection relationship diagram of the BMS controller provided by the embodiments of the present application is shown in the figure. Figure 3 A structure diagram of the voltage acquisition line fault detection device provided by the embodiments of the present application is shown in the figure. Figure 4 A structure diagram of the electronic device provided by the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0012] In order to make the purposes, technical solutions and advantages of the embodiments of the present application (hereinafter referred to as the present embodiments) clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some but not all of the embodiments of the present application. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0013] Therefore, the detailed description of the embodiments of the present application provided below in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0014] It should be noted that: similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0015] In the description of the present application, it should be noted that the terms "first", "second", "third" and the like are only used for differentiation and cannot be understood as indicating or implying relative importance. In addition, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0016] Based on the above statement, as introduced in the background, the diagnosis mode based on pure voltage amplitude comparison faces many limitations under complex working conditions and is prone to misjudgment.

[0017] For example, in the case of a dynamic load change, such as vehicle sudden acceleration or braking, the battery voltage itself will fluctuate instantaneously, at which time the voltage difference may be misjudged as a line fault, causing false positives. At the same time, some implicit open circuit faults, such as poor contact or high resistance state caused by wire harness oxidation, do not immediately lead to complete voltage zero, but show slight drift or intermittent abnormalities. Such signal changes are easily ignored by conventional threshold judgments, resulting in missed detection.

[0018] Therefore, the judgment logic that simply relies on the voltage amplitude relationship is difficult to meet the requirements of diagnostic accuracy and reliability in high safety application scenarios when facing multi-variable coupling, atypical fault modes and harsh use environments.

[0019] It should be noted that the defects of the above prior art solutions are the results obtained after practice and careful study, therefore, the discovery process of the above problems and the solutions proposed by the embodiments of the present application to solve the above problems should be considered as contributions to the present application in the process of invention, and should not be understood as technical contents known to those skilled in the art.

[0020] Based on the discovery of the above technical problems, the present embodiment provides a voltage acquisition line fault detection method. As shown in the following Figure 1 , the method comprises: S1, determining a suspicious cell with abnormal measured voltage from a plurality of cells.

[0021] S2, obtaining historical voltage information of the suspicious cell.

[0022] S3, if the historical voltage information has a harmonic with a frequency greater than an abnormal frequency threshold, it is determined that the voltage acquisition line of the suspicious cell has an open circuit fault.

[0023] In this way, by analyzing whether there is a high-frequency harmonic component in the historical voltage information of the suspicious cell, the unique electrical transient characteristics of the open circuit fault are utilized, thereby realizing accurate identification, and therefore, compared with relying only on voltage amplitude comparison, the accuracy and anti-interference ability of the diagnosis are improved.

[0024] In the present embodiment, the electronic device implementing the voltage acquisition line fault detection method can be, but is not limited to, a battery management system (BMS) controller or a slave board in a BMS in an energy storage system monitoring unit, which connects each cell through a voltage sampling circuit, periodically acquires voltage data and stores it in an internal memory. In this process, the stored historical voltage sequence is called for frequency spectrum analysis to determine whether there is a harmonic component with a frequency exceeding a preset threshold.

[0025] To make the scheme provided by the present embodiment clearer, the BMS controller is taken as the electronic device implementing the method, and each step of the method is described in detail. However, it should be understood that the operations of the flowchart can not be implemented in sequence, and the steps without logical context relationship can be reversed in order or implemented simultaneously. In addition, under the guidance of the content of the present application, one or more other operations can be added to the flowchart, or one or more operations can be removed from the flowchart. Continue to refer to Figure 1 , the method comprises: S1, determining a suspicious cell with abnormal measured voltage from a plurality of cells.

[0026] Research has found that when an open circuit fault occurs in the voltage acquisition line of a single cell during the operation of a power battery pack, its measured value may appear as zero, jump, or significantly deviate from the normal range. However, such abnormal voltage signals may be difficult to distinguish from the normal fluctuations of other cells in the initial stage, especially under dynamic operating conditions, such as sudden changes in charging and discharging current or temperature gradient changes, where the voltage distribution itself has natural fluctuations.

[0027] Therefore, traditional diagnostic methods typically rely on fixed threshold judgments or global statistical analysis, which can easily misjudge extreme voltage values ​​under normal operating conditions as faults, or fail to accurately locate the source of the anomaly due to the lack of consideration of spatial location relationships, resulting in a difficulty in balancing diagnostic sensitivity and accuracy. Consequently, current methods often cannot effectively identify open-circuit faults in their early stages or accompanied by noise interference, thus affecting the timeliness and reliability of fault response. In view of this, this embodiment provides the following optional implementation of step S1: S1-1 determines the highest and lowest voltages based on the measured voltages of multiple battery cells.

[0028] S1-2, If there is an anomaly in the relationship between the highest voltage and the lowest voltage, then determine the reference cell that is adjacent to the cell to be analyzed from among the multiple cells.

[0029] Among them, the cell to be analyzed refers to the cell corresponding to the highest or lowest voltage.

[0030] It should be understood that under normal operating conditions of a battery pack, the voltage distribution of each cell typically exhibits high uniformity, with minimal difference between its maximum and minimum values. When an open-circuit fault exists in the voltage acquisition line of a particular cell, the sampled value of that channel may experience a sudden drop, return to zero, or significantly deviate from the overall trend, leading to an increase in the overall voltage range.

[0031] like Figure 2 As shown, the BMS controller is connected to the voltage acquisition module, which collects the measured voltage of multiple cells in real time. The module sorts these voltage values, identifies the highest and lowest voltages, and then analyzes whether the relationship between them exceeds the normal range.

[0032] Specifically, if the difference between the highest and lowest voltages exceeds a preset threshold (e.g., 2.0V), the voltage distribution is deemed abnormal, indicating a potential fault risk. Furthermore, the BMS controller can employ a dynamic threshold mechanism, comparing the sum of the highest and lowest voltages with twice the average voltage. If the deviation exceeds a set tolerance δ, an anomaly detection is also triggered. This judgment logic does not rely on a fixed reference but is based on the overall voltage distribution characteristics of the battery pack, enabling it to adapt to voltage variations under different states of charge.

[0033] After confirming that the size relationship between the highest voltage and the lowest voltage is abnormal, the BMS controller further locks the battery cell corresponding to the highest voltage or the lowest voltage as the battery cell to be analyzed, because it is most likely to have a collection line fault.

[0034] To verify whether the state of the battery cell to be analyzed is truly abnormal, a local voltage continuity criterion needs to be introduced. In this process, the BMS controller selects another battery cell adjacent to the battery cell to be analyzed in physical connection or circuit topology as a reference battery cell from multiple battery cells, forming a pair of comparable objects.

[0035] Based on the above description of the battery cell to be analyzed and the reference battery cell in the embodiment, step S1 further includes: S1-3, obtaining the voltage difference between the battery cell to be analyzed and the reference battery cell.

[0036] S1-4, if the voltage difference is greater than the abnormal voltage difference threshold, the battery cell to be analyzed is determined as a suspicious battery cell.

[0037] It should be understood that the adjacent relationship in spatial position between the battery cell to be analyzed and the reference battery cell ensures that the voltages of the two are highly close under the condition of no fault. Therefore, the BMS controller can effectively identify the local voltage mutation caused by open circuit by obtaining the voltage difference between the battery cell to be analyzed and the reference battery cell and comparing it with the set abnormal voltage difference threshold. For example, in a 24-string battery pack, if the voltage of the 3rd string battery cell is significantly lower than that of other strings and the voltage difference with the adjacent string exceeds 0.2V, it can be determined as a suspicious battery cell.

[0038] Based on the above description of the suspicious battery cell in the embodiment, continue to refer to Figure 1 , and the following continues to describe step S2 in Figure 1 : S2, obtaining the historical voltage information of the suspicious battery cell.

[0039] In this embodiment, the BMS controller obtaining the historical voltage information of the suspicious battery cell means retrieving the voltage sampling sequence of the battery cell in the recent continuous time period from the storage unit of the battery management system (BMS). These data are periodically collected and cached by the voltage collection module, and the time span can be set according to actual needs, for example, voltage records in the past 10 seconds to 1 minute.

[0040] Based on the above description of the historical voltage information, continue to refer to Figure 1 , and the following continues to explain and describe step S3 in Figure 1 : S3, if the historical voltage information has a harmonic with a frequency greater than the abnormal frequency threshold, it is determined that the voltage collection line of the suspicious battery cell has an open circuit fault.

[0041] It should be understood that when the voltage acquisition line of the battery cell has an open circuit fault, it is often accompanied by a transient interruption of the electrical connection, which introduces a rapidly changing transient component in the voltage signal, causing the voltage waveform to drop sharply, rebound or oscillate at high frequency, specifically manifested as rapidly changing glitches or oscillations, with energy concentrated in the higher frequency band. Such transient characteristics are reflected in the frequency domain as energy concentrated in the high frequency band, forming significant high frequency spectral components. Therefore, the historical voltage information not only contains the change trend of the voltage amplitude, but also implies the transient response characteristics of the signal.

[0042] In the present embodiment, the BMS controller uses Fast Fourier Transform (FFT) to process the acquired historical voltage information, converts the time domain signal to frequency domain spectrum, and then detects the energy intensity of each frequency component.

[0043] During the execution of the above steps, if a significant increase in harmonic components is observed in the frequency band above 10 kHz, for example, a significant high-frequency glitch or energy peak appears, it can be determined that the voltage signal has an abnormal transient disturbance. It should be noted that a short circuit fault usually shows a slow voltage drop or low-frequency fluctuation, while a voltage change caused by a load mutation usually shows a smooth transition or low-frequency response characteristic, and does not accompany the concentrated appearance of high-frequency harmonics. Therefore, by setting an abnormal frequency threshold (such as 1 kHz or higher), the open circuit fault can be effectively distinguished from other types of electrical abnormalities or normal dynamic operating conditions.

[0044] For example, during the rapid acceleration of an electric vehicle, although the current fluctuation can cause the voltage to drop overall, the waveform remains smooth and has no significant high-frequency components; when the 5th string of single cells has a sampling line open circuit, the voltage waveform will have a sharp drop edge, and FFT analysis can clearly capture the phenomenon of a sharp increase in harmonics above 10 kHz.

[0045] In this way, based on the unique physical mechanism of the open circuit fault, high-precision identification is achieved using frequency domain characteristics, which can significantly reduce the false alarm rate and improve the robustness and accuracy of the diagnosis results.

[0046] The research finds that the voltage measurement accuracy of the battery cell is significantly affected by the ambient temperature during the operation of the power battery system, especially in a wide temperature range, such as -40°C to 125°C, the voltage collection signal is prone to thermal drift. The main source is the temperature sensitivity of the sensor, the sampling circuit and the battery itself. When the ambient or working temperature changes, the ADC reference voltage, the resistance value of the voltage divider and the OCV of the battery may all deviate, resulting in the measured voltage deviating from the true potential level. If not compensated, such temperature drift effect may be misjudged as voltage abnormality, thereby causing false diagnosis of the voltage collection line state. Therefore, when it is determined that the voltage collection line of the suspicious battery cell has an open circuit fault, step S3 specifically includes: S3-1, obtaining the current battery cell temperature of the suspicious battery cell.

[0047] S3-2, correcting the measured voltage of the suspicious battery cell according to the battery cell temperature to obtain the corrected voltage of the suspicious battery cell.

[0048] The research finds that the battery cell voltage measurement signal may produce nonlinear deviation under different temperature conditions due to the sensor characteristics, circuit component temperature drift and changes in the electrochemical behavior of the battery body. The traditional linear compensation method usually assumes a simple proportional relationship between temperature and voltage error, and uses a fixed slope or offset for correction, but in actual application, this assumption cannot accurately reflect the true drift law under complex conditions. Especially in the scenarios of low-temperature start, high-temperature operation or rapid temperature change, the voltage of the battery cell presents obvious nonlinear characteristics, and if a unified correction parameter is still used, it will lead to insufficient compensation or over-correction, thereby introducing new errors.

[0049] Therefore, the BMS controller can obtain the target correction coefficient corresponding to the battery cell temperature according to the mapping relationship between the temperature and the correction coefficient; and correct the measured voltage by using the target correction coefficient to obtain the corrected voltage.

[0050] Since the voltage collection accuracy is significantly affected by temperature changes in the power battery system, especially in extreme environmental conditions such as -30°C low-temperature working condition, the thermal response difference between the sampling circuit and the battery body will cause the voltage measurement value to drift significantly. Therefore, if this problem is not corrected, it will directly affect the accuracy of the open circuit fault diagnosis.

[0051] Therefore, continuing to refer to Figure 2 The BMS controller is also in communication connection with a temperature sensor for collecting the current battery cell temperature of the suspicious battery cell. The temperature sensor can use a high-precision temperature sensor (for example, with a resolution of 0.1°C) to accurately obtain the temperature data of each single battery cell.

[0052] During the execution of the above steps, a dynamic temperature compensation model can be constructed based on Recursive Least Squares (RLS). Instead of relying on fixed parameters, the model continuously optimizes correction coefficients through online learning. Specifically, the mapping relationship between temperature and correction coefficients pre-constructed by the BMS controller is not a static lookup table, but is generated in real time by the RLS algorithm according to historical temperature rise curves and corresponding voltage deviation data. When the current cell temperature of the suspicious cell is obtained, the corresponding target correction coefficient is determined in the dynamically updated mapping relationship according to the temperature value. This coefficient reflects the trend characteristics of voltage drift under the current temperature condition, and its mathematical form can be expressed as the proportional factor in the "temperature-voltage compensation function" , that is,

[0053] In the formula, is the offset of the cell temperature relative to the reference temperature, is the target correction coefficient to be compensated.

[0054] In this way, the deviation caused by temperature drift is eliminated by the target correction coefficient, thereby obtaining a more accurate corrected voltage.

[0055] Experimental results show that, in a -30°C environment, the original measurement error of the 12th string of single cells reaches ±50mV due to low temperature, and by introducing the dynamically adjusted correction coefficient by the RLS algorithm, it is controlled within ±5mV, significantly improving the measurement reliability.

[0056] Based on the above description of the corrected voltage in the embodiment, step S3 further includes: S3-3, if the corrected voltage is abnormal compared with the voltage threshold corrected based on the cell temperature, it is determined that the voltage acquisition line of the suspicious cell has an open circuit fault.

[0057] It can be understood that when the BMS controller determines that the suspicious cell has an open circuit risk according to the high-frequency harmonic characteristics in the historical voltage information, it still needs to further verify the authenticity of the voltage signal. If only the original measured voltage is relied on for review at this time, even if the acquisition line is normal, the measurement value may be distorted under extreme conditions of low temperature or high temperature, and the open circuit fault conclusion may be maintained incorrectly. By obtaining the current cell temperature of the suspicious cell and correcting the measured voltage based on the temperature, the error caused by temperature drift can be effectively eliminated. The corrected voltage value is compared with the voltage threshold dynamically adjusted with the temperature, so that the final determination result is closer to the actual physical state.

[0058] Referring back to Figure 2The BMS controller is also in communication connection with a CAN communication module. When it is found that the suspicious battery cell indeed has a collection line fault after excluding the temperature influence, the BMS controller reports the fault through the CAN communication module.

[0059] It should also be understood that, during long-term operation of the power battery system, the voltage collection line may have an open circuit fault due to vibration, thermal expansion and contraction, or aging of the connector, so that the main collection channel cannot obtain the real battery cell voltage. Once such a fault occurs, if there is no alternative measurement path, the BMS controller will lose the monitoring ability of the state of the battery cell, thereby affecting the accuracy of the overall SOC estimation, balance control and safety protection function, and in severe cases, it may cause overcharge or overdischarge risk.

[0060] However, it is found after research that the traditional diagnosis method usually only performs alarm processing after identifying the open circuit fault, lacks a recovery mechanism for the measurement ability, and causes the BMS controller to be in a state of information loss, thereby reducing the reliability and safety of the battery pack operation. In view of this, the voltage collection line fault detection method provided in the embodiment further comprises: S4. Under the condition that it is determined that the voltage collection line of the suspicious battery cell has an open circuit fault, switching to collecting the voltage of the suspicious battery cell through a backup voltage collection line.

[0061] It can be understood that, in order to improve the fault tolerance ability, a redundant architecture is adopted at the hardware design level, an independent backup voltage collection line is configured for each battery cell, and a double backup collection channel is formed. The design covers the voltage collection module and the related connection path, and ensures that there is still a physically separated backup signal path when the main channel fails.

[0062] Therefore, during the execution of the above steps, when it is confirmed that the voltage collection line of the suspicious battery cell has an open circuit fault, the channel switching mechanism is triggered immediately. Specifically, the BMS controller disconnects the failed main collection line through a switch matrix or a relay device, simultaneously connects the backup voltage collection line and the sampling circuit, so that the voltage signal is input to the BMS controller through the backup channel. The whole switching process does not need manual intervention and is automatically completed based on the preset logic, and the switching time is less than 10 milliseconds, thereby ensuring the continuity and timeliness of voltage data collection.

[0063] In this way, by introducing the hardware-level double backup design, the voltage monitoring ability of the suspicious battery cell is quickly restored after the fault occurs, and the data interruption caused by a single point fault is effectively avoided.

[0064] The research also found that in the power battery system, the abnormality of a single cell may not only be caused by the voltage acquisition line fault, but also may reflect that the cell itself has internal defects or performance degradation. When the open circuit fault is determined through the main acquisition line and switched to the backup voltage acquisition line, if the voltage sequence obtained by the backup channel still shows abnormality, it indicates that the problem is not limited to the external sampling line, but the suspect cell itself has substantial faults such as increased internal resistance, capacity attenuation or micro short circuit. At this time, if only stay at the channel switching level without further evaluating the cell state, it may lead to continuous accumulation of fault risk, thereby affecting the safe operation of the entire battery pack. In view of this, the voltage acquisition line fault detection method provided by the embodiment further comprises: S6, the voltage sequence collected through the backup voltage acquisition line is used as the voltage information to be analyzed.

[0065] S7, if the voltage information to be analyzed indicates that the suspect cell has an abnormality, a target cell module including the suspect cell is isolated.

[0066] It should be understood that in the power battery system, the cells are usually integrated in a modular manner, and a plurality of cells are connected in series or parallel to form a cell module that can be independently installed and managed. When a suspect cell is diagnosed as an open circuit fault through the main acquisition line and still shows abnormal voltage characteristics after switching to the backup voltage acquisition line, it indicates that the cell may have substantial faults at the ontology level, such as internal short circuit, lithium precipitation or precursor of thermal runaway.

[0067] Therefore, during the execution of the above steps, the BMS controller uses the voltage sequence continuously obtained through the backup voltage acquisition line as the voltage information to be analyzed, for evaluating the actual working state of the suspect cell after restoring communication. If the voltage sequence shows characteristics such as continuous low, severe fluctuation or abnormal response, it is determined that the suspect cell has irreversible performance degradation or internal fault. On this basis, the BMS controller starts the electrical isolation mechanism and implements the cutting operation on the target cell module including the suspect cell through the intelligent circuit breaker.

[0068] The intelligent circuit breaker, as a key execution element, has a fast response capability and can disconnect the high-voltage connection between the fault module and the main loop within milliseconds, thereby realizing complete electrical isolation of the module.

[0069] The research also found that in the power battery system, the open circuit fault of the voltage acquisition line is a connection abnormality at the signal level, but it may be accompanied or caused by deeper electrical safety risks. For example, the line breakage may be caused by insulation layer damage, connector loosening or external mechanical damage. Such physical defects may further evolve into insulation failure between the high-voltage loop and the battery pack shell under certain conditions. In view of this, the voltage acquisition line fault detection method provided by the embodiment further comprises: S8, under the condition that the voltage collection line of the suspicious battery cell has an open-circuit fault, acquiring the resistance value of the insulation resistance; S9, if the resistance value indicates that the insulation resistance has an abnormality, cutting off the high-voltage loop of the battery pack.

[0070] During the execution of the above steps, after it is determined that the voltage collection line of the suspicious battery cell has an open-circuit fault, the BMS controller immediately starts a safety linkage mechanism and triggers a high-voltage insulation resistance test module to detect the resistance value of the insulation resistance. The test module applies a direct current voltage of not less than 500 V as a measurement excitation to simulate the insulation stress under actual high-voltage working conditions, so as to ensure that the test result is representative.

[0071] Specifically, the BMS controller monitors whether the insulation resistance is greater than 100 Ω / V, which is a benchmark threshold, in real time. This index meets the requirement of the functional safety specification for electric vehicles on the insulation performance of high-voltage components. On this basis, if the measured resistance value is lower than the specified limit value, it indicates that the insulation system has an abnormality, such as the presence of a short-circuit path or moisture intrusion. At this time, the BMS controller will determine that the current state is in a high-risk state and immediately perform a high-voltage loop cutting-off operation.

[0072] It should be understood that this action is realized by controlling the main positive relay, the main negative relay or a special circuit breaker, so as to quickly disconnect the power connection between the power battery and the external load and prevent the leakage of dangerous voltage. The whole process does not require manual intervention, the response is timely, and the occurrence of electric shock accidents and secondary faults is effectively prevented.

[0073] Based on the same inventive concept as the voltage collection line fault detection method provided in the present embodiment, the present embodiment also provides a voltage collection line fault detection device. The device includes at least one software function module stored in the form of software in a memory or solidified in an electronic device. A processor in the electronic device is used to execute the executable modules stored in the memory. For example, the device includes software function modules and computer programs. Please refer to Figure 3 From the functional point of view, the device can include: A battery cell quick screening module for determining suspicious battery cells with abnormal measured voltages from a plurality of battery cells; A historical voltage module for acquiring historical voltage information of the suspicious battery cells; A fault diagnosis module for determining that the voltage collection line of the suspicious battery cell has an open-circuit fault if the historical voltage information has a harmonic with a frequency greater than an abnormal frequency threshold.

[0074] In the present embodiment, the battery cell quick screening module is used to implement step S1 in Figure 1 , the historical voltage module is used to implement step S2 in Figure 1 , and the fault diagnosis module is used to implement step S3 in Figure 1Step S3 in FIG. 3. Therefore, the detailed description of each module above can refer to the detailed description of the corresponding step.

[0075] Since the voltage collection line fault detection device has the same inventive concept as the voltage collection line fault detection method provided by the embodiment, the voltage collection line fault detection device can also implement other steps or sub-steps of the method through the modules above.

[0076] Optionally, when it is determined that the voltage collection line of the suspicious battery cell has an open circuit fault, the fault diagnosis module is further configured to: acquire a current battery cell temperature of the suspicious battery cell; correct the measured voltage of the suspicious battery cell according to the battery cell temperature to obtain a corrected voltage of the suspicious battery cell; if the corrected voltage is abnormal compared with the voltage threshold corrected based on the battery cell temperature, determine that the voltage collection line of the suspicious battery cell has an open circuit fault.

[0077] Optionally, the fault diagnosis module is further configured to: obtain a target correction coefficient corresponding to the battery cell temperature according to a mapping relationship between the temperature and the correction coefficient constructed in advance; correct the measured voltage by using the target correction coefficient to obtain the corrected voltage.

[0078] Optionally, the battery cell rapid screening module is further configured to: determine a highest voltage and a lowest voltage from the measured voltages of the plurality of battery cells; if a size relationship between the highest voltage and the lowest voltage is abnormal, determine a reference battery cell adjacent to a battery cell to be analyzed from the plurality of battery cells, wherein the battery cell to be analyzed represents a battery cell corresponding to the highest voltage or the lowest voltage; acquire a voltage difference between the battery cell to be analyzed and the reference battery cell; if the voltage difference is greater than an abnormal voltage difference threshold, treat the battery cell to be analyzed as the suspicious battery cell.

[0079] Optionally, the suspicious battery cell is further configured with a backup voltage collection line, and the fault diagnosis module is further configured to: under the condition that it is determined that the voltage collection line of the suspicious battery cell has an open circuit fault, switch to collecting the voltage of the suspicious battery cell through the backup voltage collection line.

[0080] Optionally, the plurality of battery cells are configured as a plurality of battery cell modules, and the fault diagnosis module is further configured to: take the voltage sequence collected through the backup voltage collection line as the voltage information to be analyzed; if the voltage information to be analyzed indicates that the suspicious battery cell is abnormal, isolate a target battery cell module including the suspicious battery cell.

[0081] Optionally, the battery pack including the plurality of battery cells is configured with an insulation resistance, and the fault diagnosis module is further configured to: under the condition that the open-circuit fault of the voltage acquisition line of the suspicious battery cell is determined, acquire the resistance value of the insulation resistance; if the resistance value indicates that the insulation resistance is abnormal, cut off the high-voltage loop of the battery pack.

[0082] In addition, each functional module in each embodiment of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0083] It should also be understood that the above embodiments, if implemented in the form of software functional modules and sold or used as independent products, can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the parts that make contributions to the prior art or parts of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application.

[0084] Therefore, the present embodiment also provides a storage medium, which is a computer readable storage medium. The storage medium stores a computer program, and the computer program is executed by a processor to implement the voltage acquisition line fault detection method provided by the present embodiment. The storage medium can be a U disk, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0085] The present embodiment also provides an electronic device for implementing the voltage acquisition line fault detection method. As shown in Figure 4 The electronic device can include a processor 22 and a memory 21. The memory 21 stores a computer program, and the processor implements the voltage acquisition line fault detection method provided by the present embodiment by reading and executing the computer program corresponding to the above embodiments in the memory 21.

[0086] Continuing to refer to Figure 4 The electronic device further includes a communication unit 23. The memory 21, the processor 22 and the communication unit 23 are directly or indirectly electrically connected to each other through a system bus 24 to realize data transmission or interaction.

[0087] The memory 21 can be any electronic, magnetic, optical, or other physical information record storage device that stores executable instructions, data, etc. In some embodiments, the memory 21 can be, but is not limited to, a volatile memory, a non-volatile memory, a storage drive, etc.

[0088] In some embodiments, the volatile memory can be a Random Access Memory (RAM); in some embodiments, the non-volatile memory can be a Read Only Memory (ROM), a Programmable Read-Only Memory (PROM), an Erasable Programmable Read-Only Memory (EPROM), an Electric Erasable Programmable Read-Only Memory (EEPROM), a flash memory, etc.; in some embodiments, the storage drive can be a disk drive, a solid-state drive, any type of storage disk (e.g., an optical disk, a DVD, etc.), or similar storage media, or a combination thereof, etc.

[0089] The communication unit 23 is configured to transceive data over a network. In some embodiments, the network can include a wired network, a wireless network, a fiber optic network, a telecommunications network, an intranet, the Internet, a Local Area Network (LAN), a Wide Area Network (WAN), a Wireless Local Area Network (WLAN), a Metropolitan Area Network (MAN), a Wide Area Network (WAN), a Public Switched Telephone Network (PSTN), a Bluetooth network, a ZigBee network, or a Near Field Communication (NFC) network, etc., or any combination thereof. In some embodiments, the network can include one or more network access points. For example, the network can include wired or wireless network access points, such as base stations and / or network switching nodes, through which one or more components of the service request processing system can connect to the network to exchange data and / or information.

[0090] The processor 22 can be an integrated circuit chip with signal processing capability and can include one or more processing cores (e.g., a single-core processor or a multi-core processor). By way of example only, the processor can include a Central Processing Unit (CPU), an Application Specific Integrated Circuit (ASIC), an Application Specific Instruction-set Processor (ASIP), a Graphics Processing Unit (GPU), a Physics Processing Unit (PPU), a Digital Signal Processor (DSP), a Field Programmable Gate Array (FPGA), a Programmable Logic Device (PLD), a controller, a microcontroller unit, a Reduced Instruction Set Computing (RISC), or a microprocessor, or any combination thereof.

[0091] It can be understood that Figure 4 The structure shown is merely schematic. The electronic device can also have more or fewer components than Figure 4 shown, or have a different configuration than Figure 4 shown. Figure 4 Each component shown can be implemented in hardware, software, or a combination thereof.

[0092] It should be understood that all the devices and methods disclosed in the above embodiments can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the drawings show the possible implementation architectures, functions and operations of the devices, methods and computer program products according to the embodiments of the present application. In this regard, each block in the flowcharts or block diagrams can represent a module, a program segment or a part of code, which contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur in different orders from those noted in the drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and sometimes they can be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and the combination of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0093] The above describes only various embodiments of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A voltage acquisition line fault detection method, characterized by, The method includes: From multiple battery cells, suspicious cells with abnormal measured voltage were identified; Obtain the historical voltage information of the suspected battery cell; If the historical voltage information contains harmonics with a frequency greater than the abnormal frequency threshold, then it is determined that the voltage acquisition line of the suspected battery cell has an open circuit fault.

2. The method of claim 1, wherein, When it is determined that the voltage acquisition line of the suspected battery cell has an open circuit fault, the method further includes: Obtain the current cell temperature of the suspected battery cell; The measured voltage of the suspected battery cell is corrected based on the cell temperature to obtain the corrected voltage of the suspected battery cell; If the corrected voltage is abnormal compared to the voltage threshold corrected based on the cell temperature, it is determined that the voltage acquisition line of the suspected cell has an open circuit fault.

3. The method of claim 2, wherein, The corrected voltage of the suspected battery cell is obtained by correcting the measured voltage of the suspected battery cell based on the cell temperature, including: Based on the pre-established mapping relationship between temperature and correction coefficient, the target correction coefficient corresponding to the cell temperature is obtained; The measured voltage is corrected using the target correction factor to obtain the corrected voltage.

4. The method of claim 1, wherein, Suspicious battery cells with abnormal measured voltages were identified from multiple battery cells, including: Based on the measured voltages of the multiple battery cells, the highest and lowest voltages are determined. If there is an abnormal relationship between the highest voltage and the lowest voltage, a reference cell adjacent to the cell to be analyzed is determined from the plurality of cells, wherein the cell to be analyzed is the cell corresponding to the highest voltage or the lowest voltage; Obtain the voltage difference between the cell to be analyzed and the reference cell; If the voltage difference is greater than the abnormal voltage difference threshold, the cell to be analyzed is considered a suspicious cell.

5. The method of claim 1-4, wherein, The suspected battery cell is also equipped with a backup voltage acquisition line, and the method further includes: If it is determined that the voltage acquisition line of the suspected battery cell has an open circuit fault, the voltage of the suspected battery cell is switched to be acquired through the backup voltage acquisition line.

6. The method of claim 5, wherein, The plurality of battery cells are configured into a plurality of battery cell modules, and the method further includes: The voltage sequence acquired through the backup voltage acquisition line is used as the voltage information to be analyzed; If the voltage information to be analyzed indicates that the suspected battery cell is abnormal, the target battery cell module including the suspected battery cell will be isolated.

7. The voltage acquisition line fault detection method according to claim 1, characterized in that, The battery pack comprising the plurality of cells is configured with an insulation resistance, and the method further includes: Under the condition that the voltage acquisition line of the suspected battery cell has an open circuit fault, the resistance value of the insulation resistance is obtained; If the resistance value indicates an abnormality in the insulation resistance, then the high-voltage circuit of the battery pack is disconnected.

8. A voltage acquisition line fault detection device, characterized in that, The device includes: The cell rapid screening module is used to identify suspicious cells with abnormal measured voltages from multiple cells. The historical voltage module is used to acquire historical voltage information of the suspected battery cell; The fault diagnosis module is used to determine that the voltage acquisition line of the suspected battery cell has an open circuit fault if the historical voltage information contains harmonics with a frequency greater than the abnormal frequency threshold.

9. A storage medium, characterized in that, The storage medium stores a computer program, which, when executed by a processor, implements the voltage acquisition line fault detection method according to any one of claims 1-7.

10. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory storing a computer program, which, when executed by the processor, implements the voltage acquisition line fault detection method according to any one of claims 1-7.

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