Battery internal short circuit identification system and method

Abstract

The invention discloses a battery internal short circuit identification system and method, and belongs to the technical field of communication, the battery internal short circuit identification system comprises a switching power supply, an excitation unit, a plurality of battery units and a server, and each battery unit comprises a battery module and a BMS; the switching power supply converts alternating current into direct current; any BMS sends an excitation request to an excitation unit under the condition of determining that the battery module meets the EIS test condition, acquires target excitation current and voltage response after the battery module receives the target excitation current, and sends the calculated EIS parameters of the battery module to a server based on the target excitation current and voltage response; after the excitation unit receives the excitation request, the direct current is converted into target excitation current, and the target excitation current is sent to the battery module; and the server receives the EIS parameter, and judges whether the battery module is internally short-circuited based on the EIS parameter after determining that the battery internal short-circuit identification period of the battery module is reached. The identification difficulty of the short circuit in the battery is reduced, and the identification accuracy is improved.

Description

Technical Field

[0001] The present application relates to the field of communication technology, and in particular to a system and method for identifying a short circuit in a battery. Background Art

[0002] With the rapid development of communication technology and new energy fields, lithium batteries are widely used in communication rooms, electric vehicles and other key systems as efficient energy storage devices. However, short circuits in batteries are one of the main reasons for the degradation of battery performance and increased safety risks. Therefore, timely and accurate identification of short circuits in batteries is crucial to ensure the stable operation of power systems.

[0003] At present, the electrochemical impedance spectroscopy (EIS) method is a common method for identifying short circuits in batteries. It identifies and evaluates whether there are micro short circuits inside lithium batteries by fitting an electrochemical equivalent circuit model. These models are usually composed of components such as resistors, capacitors, and inductors to simulate various electrochemical processes inside the battery. However, this method often leads to insufficient absolute accuracy of the measured parameters due to parasitic parameters such as parasitic resistance, capacitance, and inductance in the acquisition and excitation circuits, resulting in low accuracy of the fitting model. Moreover, in the communication room, lithium batteries are frequently charged and discharged every day. This dynamic working condition makes the EIS measurement results affected by the charging and discharging process itself, which also increases the difficulty of identifying internal short circuits.

[0004] Therefore, the traditional method of identifying short circuits in batteries has the problems of great difficulty in identification and low identification accuracy. Summary of the invention

[0005] The embodiments of the present application provide a battery internal short circuit identification system and method, which are used to solve the problems of high identification difficulty and low identification accuracy in traditional battery internal short circuit identification methods.

[0006] In a first aspect, an embodiment of the present application provides a battery internal short circuit identification system, the system comprising: a switching power supply, an excitation unit, a plurality of battery cells, and a server, wherein any battery cell comprises a battery module and a battery management system (Battery Management System, BMS);

[0007] The switching power supply is used to convert alternating current into direct current for powering the communication equipment;

[0008] For any BMS, the BMS is used to send an excitation request to the excitation unit when it is determined that the battery module meets the electrochemical impedance spectroscopy (EIS) test conditions, and after the battery module receives the target excitation current, collect the target excitation current and the voltage response of the battery module based on the target excitation current, calculate the EIS parameters of the battery module based on the target excitation current and send the EIS parameters of the battery module to the server;

[0009] The excitation unit is configured to, after receiving the excitation request, convert the direct current into the target excitation current and send the target excitation current to the battery module;

[0010] The server is used to receive the EIS parameters of the battery module, and after determining that a battery internal short circuit identification cycle of the battery module has arrived, determine whether the battery module has an internal short circuit based on the received EIS parameters.

[0011] In some embodiments, the excitation unit comprises a DC / AC module and a switch matrix, wherein:

[0012] The DC / AC module is used to send a target output frequency to the BMS after receiving the excitation request, and after receiving a reception response, convert the direct current into the target excitation current, and control the switch matrix to conduct a path between the DC / AC module and the battery module;

[0013] The BMS is further configured to send the receiving response to the DC / AC module after receiving the target output frequency;

[0014] The BMS is specifically used to determine a collection frequency based on the target output frequency, and to collect the target excitation current and a voltage response of the battery module based on the target excitation current based on the collection frequency, wherein the target excitation current is collected by the BMS through a current sensor.

[0015] In some embodiments, if multiple BMSs simultaneously send excitation requests to the DC / AC module, the DC / AC module is further configured to:

[0016] Determining priorities of the plurality of BMSs based on preset priorities of the battery modules;

[0017] Based on the priorities of the multiple BMSs, determining a target BMS; wherein the target BMS is a BMS with the highest priority among the current BMSs, and the current BMS includes a BMS among the multiple BMSs that has not received a target output frequency;

[0018] sending the target output frequency to the target BMS, and after receiving a reception response, converting the direct current into the target excitation current, and controlling the switch matrix to conduct a path between the DC / AC module and the battery module corresponding to the target BMS;

[0019] When it is determined that the preset first disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module corresponding to the target BMS, and the process returns to the step of determining the target BMS based on the priority of the multiple BMSs.

[0020] In some embodiments, the DC / AC module is further used for:

[0021] After applying a target excitation current to the battery module corresponding to the target BMS, recording the number of excitations;

[0022] If the number of excitations is less than a preset number of excitations, after determining that a preset time interval has been reached, applying the target excitation current to the battery module again;

[0023] If the number of excitations is equal to the preset number of excitations, the number of excitations is reset to zero and when it is determined that the preset second disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module corresponding to the target BMS.

[0024] In some embodiments, the DC / AC module is specifically used for:

[0025] Based on the excitation request, determining a plurality of output frequencies corresponding to the excitation request from a preset corresponding relationship;

[0026] Sending a target output frequency to the BMS, and after receiving a receiving response, converting the direct current into the target excitation current, and controlling the switch matrix to conduct the path between the DC / AC module and the battery module, wherein the target output frequency is the highest output frequency among the current output frequencies, and the current output frequency includes the output frequency that is not sent among the multiple output frequencies;

[0027] When it is determined that the preset third disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module, and the process returns to the step of sending the target output frequency to the BMS.

[0028] In some embodiments, the BMS is specifically used for:

[0029] Monitoring the status of the battery module;

[0030] If it is determined that the continuous static time of the battery module meets the preset static time, and if it is determined that the interval between the current moment and the moment when the EIS parameters of the battery module were last obtained meets the preset interval time, then it is determined that the battery module meets the electrochemical impedance spectroscopy EIS test conditions.

[0031] In some embodiments, the server is specifically used to:

[0032] Determining a first change trend of the EIS parameter based on the received EIS parameter and the EIS parameter received during a historical battery internal short circuit identification cycle;

[0033] Based on the first change trend and a preset second change trend, an internal short circuit of the battery module is identified, wherein the second change trend is a change trend of an EIS parameter corresponding to when the battery module is not internally short-circuited.

[0034] In some embodiments, the EIS parameters include impedance modulus, real part and phase angle, and the server is specifically configured to:

[0035] Based on the received EIS parameters and the EIS parameters received in the historical battery internal short circuit identification cycle, respectively determine the impedance modulus change trend, the real part change trend and the phase angle change trend;

[0036] Comparing the impedance modulus change trend with the impedance modulus change trend in the second change trend to obtain a first comparison result, and comparing the real part change trend with the real part change trend in the second change trend to obtain a second comparison result, and comparing the phase angle change trend with the phase angle change trend in the second change trend to obtain a third comparison result;

[0037] If any comparison result among the first comparison result, the second comparison result and the third comparison result is inconsistent, it is determined that the battery module is internally short-circuited.

[0038] In some embodiments, the server is further configured to:

[0039] After determining that the battery module is internally short-circuited, determining the internal short-circuit severity level of the battery module based on the EIS parameter of the battery module and the EIS parameter range of the battery module corresponding to each preset internal short-circuit severity level;

[0040] Based on the internal short circuit severity level, an early warning is issued to the battery module.

[0041] In a second aspect, an embodiment of the present application provides a method for identifying a short circuit in a battery, which is applied to the system for identifying a short circuit in a battery in the first aspect. The method includes:

[0042] For the BMS in any battery unit, when determining that the battery module corresponding to the BMS meets the electrochemical impedance spectroscopy EIS test conditions, the BMS sends an excitation request to the excitation unit, so that the excitation unit converts direct current into a target excitation current after receiving the excitation request, and sends the target excitation current to the battery module, wherein the direct current is obtained by converting alternating current by a switching power supply;

[0043] After the battery module receives the target excitation current, the BMS collects the target excitation current and a voltage response of the battery module generated based on the target excitation current;

[0044] The BMS calculates the EIS parameters of the battery module based on the target excitation current and the voltage response, and sends the EIS parameters of the battery module to a server, so that after the server receives the EIS parameters of the battery module and determines that a battery internal short circuit identification cycle of the battery module has been reached, it determines whether the battery module has an internal short circuit based on the received EIS parameters.

[0045] In some embodiments, the excitation unit comprises a DC / AC module and a switch matrix, wherein:

[0046] The DC / AC module, after receiving the excitation request, sends a target output frequency to the BMS, and after receiving a reception response, converts the direct current into the target excitation current, and controls the switch matrix to conduct a path between the DC / AC module and the battery module;

[0047] The BMS, after receiving the target output frequency, sends the reception response to the DC / AC module;

[0048] The BMS determines a collection frequency based on the target output frequency, and collects the target excitation current and a voltage response of the battery module based on the target excitation current based on the collection frequency, wherein the target excitation current is collected by the BMS through a current sensor.

[0049] In some embodiments, when the BMS determines that the battery module corresponding to the BMS meets the electrochemical impedance spectroscopy (EIS) test conditions, the BMS sends an excitation request to the excitation unit, including:

[0050] Monitoring the status of the battery module;

[0051] If it is determined that the continuous static time of the battery module meets the preset static time, and if it is determined that the interval between the current moment and the moment when the EIS parameters of the battery module were last obtained meets the preset interval time, then it is determined that the battery module meets the electrochemical impedance spectroscopy EIS test conditions.

[0052] In some embodiments, the server determines a first change trend of the EIS parameter based on the received EIS parameter and the EIS parameter received in a historical battery internal short circuit identification cycle;

[0053] Based on the first change trend and a preset second change trend, an internal short circuit of the battery module is identified, wherein the second change trend is a change trend of an EIS parameter corresponding to when the battery module is not internally short-circuited.

[0054] In some embodiments, the EIS parameters include an impedance modulus, a real part, and a phase angle, and the server determines the impedance modulus change trend, the real part change trend, and the phase angle change trend based on the received EIS parameters and the EIS parameters received in the historical battery internal short circuit identification cycle;

[0055] Comparing the impedance modulus change trend with the impedance modulus change trend in the second change trend to obtain a first comparison result, and comparing the real part change trend with the real part change trend in the second change trend to obtain a second comparison result, and comparing the phase angle change trend with the phase angle change trend in the second change trend to obtain a third comparison result;

[0056] If any comparison result among the first comparison result, the second comparison result and the third comparison result is inconsistent, it is determined that the battery module is internally short-circuited.

[0057] In some embodiments, after determining that the battery module is internally short-circuited, the server determines the internal short-circuit severity level of the battery module based on the EIS parameter of the battery module and the EIS parameter range of the battery module corresponding to each preset internal short-circuit severity level;

[0058] Based on the internal short circuit severity level, an early warning is issued to the battery module.

[0059] In a third aspect, an embodiment of the present application provides a storage medium. When a computer program in the storage medium is executed by a processor of a BMS, the BMS is capable of executing the above-mentioned method for identifying a short circuit in a battery.

[0060] In a fourth aspect, an embodiment of the present application provides a computer program product, which, when called and executed by a BMS, enables the electronic device to execute the above-mentioned method for identifying a short circuit in a battery.

[0061] In an embodiment of the present application, a battery internal short circuit identification system includes: a switching power supply, an excitation unit, a plurality of battery cells, and a server, wherein any battery cell includes a battery module and a battery management system BMS; a switching power supply, used to convert alternating current into direct current for powering communication equipment; for any BMS, the BMS is used to send an excitation request to the excitation unit when it is determined that the battery module meets the EIS test conditions, and after the battery module receives the target excitation current, collect the target excitation current and the voltage response generated by the battery module based on the target excitation current, calculate the EIS parameters of the battery module based on the target excitation current and the voltage response, and send the EIS parameters to the server; the excitation unit is used to convert direct current into a target excitation current after receiving the excitation request, and send the target excitation current to the battery module; the server is used to receive the EIS parameters of the battery module, and after determining that the battery internal short circuit identification cycle of the battery module has been reached, determine whether the battery module is internally short-circuited based on the received EIS parameters. In this way, the battery EIS measurement is performed through the excitation unit, which reduces the difficulty of identifying internal short circuits in the battery. Based on the EIS parameters of the battery module, after determining that the battery internal short circuit identification cycle has arrived at the battery module, it is determined whether the battery module has an internal short circuit based on the received EIS parameters, which does not depend on the battery model, thereby improving the identification accuracy.

[0062] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures specifically pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0064] Figure 1 A schematic diagram of the architecture of a battery internal short circuit identification system provided in an embodiment of the present application;

[0065] Figure 2 A schematic diagram of the architecture of another battery internal short circuit identification system provided in an embodiment of the present application;

[0066] Figure 3 A flow chart of a method for identifying a short circuit in a battery provided in an embodiment of the present application;

[0067] Figure 4 A flow chart of a server determining a short circuit in a battery provided in an embodiment of the present application. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical scheme and advantages of the present application clearer, the technical scheme in the embodiment of the present application will be clearly and completely described below in conjunction with the drawings in the embodiment of the present application. Obviously, the described embodiment is only a part of the embodiment of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be arbitrarily combined with each other. In addition, although the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in an order different from that here.

[0069] The terms "first" and "second" in the specification and claims of this application and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects associated before and after are in an "or" relationship. In addition, the term "includes" and any of their variations are intended to cover non-exclusive protection. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. "Multiple" in this application can mean at least two, for example, two, three or more, and the embodiments of this application are not limited.

[0070] The following is a description of exemplary embodiments of the present application in conjunction with the accompanying drawings, including various details of the embodiments of the present application to facilitate understanding, which should be considered as merely exemplary. Therefore, those of ordinary skill in the art should recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope of the present application. Similarly, for the sake of clarity and conciseness, the description of well-known functions and structures is omitted in the following description. It should be noted that in the embodiments of the present application, certain software, components, models and other existing solutions in the industry may be mentioned, which should be considered as exemplary, and their purpose is only to illustrate the feasibility of the implementation of the technical solution of the present application, but it does not mean that the applicant has or will necessarily use the solution.

[0071] In the technical solution of this application, the acquisition, transmission, storage, and use of data are in compliance with the requirements of relevant national laws and regulations.

[0072] Before introducing the battery internal short circuit identification system and method provided by the embodiments of the present application, in order to facilitate understanding, the technical background of the embodiments of the present application is first introduced in detail below.

[0073] With the rapid development of communication technology and new energy fields, lithium batteries are widely used in communication rooms, electric vehicles and other key systems as efficient energy storage devices. However, short circuits in batteries are one of the main reasons for the degradation of battery performance and increased safety risks. Therefore, timely and accurate identification of short circuits in batteries is crucial to ensure the stable operation of power systems.

[0074] At present, the electrochemical impedance spectroscopy (EIS) method is a common method for identifying short circuits in batteries. It identifies and evaluates whether there are micro short circuits inside lithium batteries by fitting an electrochemical equivalent circuit model. These models are usually composed of components such as resistors, capacitors, and inductors to simulate various electrochemical processes inside the battery. However, this method often leads to insufficient absolute accuracy of the measured parameters due to parasitic parameters such as parasitic resistance, capacitance, and inductance in the acquisition and excitation circuits, resulting in low accuracy of the fitting model. Moreover, in the communication room, lithium batteries are frequently charged and discharged every day. This dynamic working condition makes the EIS measurement results affected by the charging and discharging process itself, which also increases the difficulty of identifying internal short circuits.

[0075] In view of this, in order to solve the problems of difficult identification and low identification accuracy in the traditional battery internal short circuit identification method, the present application embodiment provides a battery internal short circuit identification system and method. The following describes some preferred embodiments of the present application in conjunction with the drawings of the specification.

[0076] In order to facilitate the understanding of this application, the technical terms involved in this application are:

[0077] Fast Fourier Transform (FFT) is an efficient algorithm of Discrete Fourier Transform (DFT), which is a computational method for converting a time domain system into a frequency domain system analysis.

[0078] Internal short circuit: refers to a slight short circuit between the positive and negative electrodes of a lithium-ion battery due to manufacturing defects or lithium deposition.

[0079] Characteristic frequency: Certain characteristics of lithium-ion batteries will have a greater response under specific frequency excitation, and this frequency point is called the characteristic frequency.

[0080] Please refer to Figure 1, is a schematic diagram of the architecture of a battery internal short circuit identification system provided in an embodiment of the present application, the system comprising: a switching power supply, an excitation unit, a plurality of battery cells, and a server, wherein any battery cell comprises a battery module and a battery management system BMS;

[0081] The switching power supply is used to convert AC power into DC power for powering the communication equipment. In specific implementation, the switching power supply is also used to charge the battery module.

[0082] For any BMS, the BMS is used to send an excitation request to the excitation unit when it is determined that the battery module meets the electrochemical impedance spectroscopy (EIS) test conditions, and after the battery module receives the target excitation current, collect the target excitation current and the voltage response of the battery module based on the target excitation current, calculate the EIS parameters of the battery module based on the target excitation current and the voltage response, and send the EIS parameters of the battery module to the server.

[0083] During specific implementation, in order to ensure that the battery module is in a stable state during the electrochemical impedance spectroscopy (EIS) test, the BMS can monitor the state of the battery module, determine whether the continuous static time of the battery module meets the preset static time, and determine whether the interval between the current moment and the last time the EIS parameters of the battery module were obtained meets the preset interval time, and then determine that the battery module meets the EIS test conditions.

[0084] For example, the preset resting time is set to 30 minutes, that is, the minimum time that the battery must rest continuously is 30 minutes, and the preset interval time is set to 24 hours, that is, the minimum interval time between two EIS tests is 24 hours. A high-precision current sensor can be used to monitor the charge and discharge current of the battery module in real time, and the voltage data of the battery module is collected at the same time to assist in judging the battery state. When the battery current is detected to be close to zero (for example, less than a certain threshold, such as 0.1A), the rest timer is started. If the battery current changes during the timing (such as exceeding the threshold), the rest timer is reset and returns to the non-steady state, and the timestamp of each EIS test is recorded. After the battery enters the steady state, check whether the time difference between the current moment and the last time the EIS parameters of the battery module are obtained meets the preset interval time. Only when the continuous resting time of the battery module meets the preset resting time of 30 minutes, and the time difference between the current moment and the last EIS test meets the preset interval time of 24 hours, it is determined that the battery module meets the EIS test conditions. In this way, not only the accuracy of the EIS test results is guaranteed, but also the reliability and efficiency of the system are improved.

[0085] In specific implementation, when the BMS determines that the EIS test conditions are met, it can send an excitation request to the excitation unit through a communication interface (such as CAN bus, Ethernet, etc.), wherein the excitation request can include the identification of the target battery module, and after the battery module receives the target excitation current, the target excitation current and the voltage response generated by the battery module are synchronously collected through a high-precision current sensor and a voltage sensor. The collected target excitation current and voltage response are related to the current and time domain voltage. Therefore, the data can be converted into the frequency domain through a fast Fourier transform (FFT), and the complex impedance Z(θ) is calculated based on the current and voltage in the frequency domain. The required EIS parameters, such as the impedance modulus |Z|, the real part Zre, the imaginary part Zim and the phase angle θ, are extracted from the complex impedance, and the EIS parameters of the battery module are sent to the server.

[0086] The excitation unit is used to convert direct current into a target excitation current after receiving an excitation request, and send the target excitation current to the battery module.

[0087] The server is used to receive the EIS parameters of the battery module, and after determining that the battery module reaches the battery internal short circuit identification cycle, determine whether the battery module has an internal short circuit based on the received EIS parameters.

[0088] In specific implementation, the server determines a first change trend of the EIS parameters based on the received EIS parameters and the EIS parameters received during the historical battery internal short circuit identification cycle, and then identifies the internal short circuit of the battery module based on the first change trend and a pre-set second change trend, wherein the second change trend is the change trend of the EIS parameters corresponding to when the battery module is not internally short-circuited.

[0089] In specific implementation, the BMS performs an EIS test on each pair of battery modules, that is, sends the EIS parameters to the server, and the server receives these EIS parameters and stores them in the database to ensure the integrity and traceability of historical data. After determining the battery internal short circuit identification cycle that reaches the battery module, for example, the battery internal short circuit identification cycle is one week, assuming that 7 EIS parameters are received within a week, the server can calculate the EIS parameters uploaded by the BMS within a week to obtain the average value of the EIS parameters, and compare the obtained average value of the EIS parameters with the EIS parameters received in the historical battery internal short circuit identification cycle, and the first change trend of the EIS parameters in this cycle can be obtained. Then, the first change trend is compared with the second change trend of the EIS parameters corresponding to the battery module when it is not internally short-circuited to evaluate the difference, and judge whether the battery module is internally short-circuited based on the comparison result. If the first change trend deviates significantly from the second change trend, it is considered that the battery module may have an internal short circuit problem.

[0090] Among them, the EIS parameters include impedance modulus |Z|, real part Zre and phase angle θ. The second change trend can be based on a large amount of experimental data or historical records to perform EIS tests on normally operating battery modules, and record the change trend of their EIS parameters. According to the experimental data, as the number of battery cell cycles increases, at the same (remaining available power) (State of Charge, SOC) and temperature at the characteristic frequency, the impedance modulus |Z| increases monotonically, the real part Zre increases monotonically, and the phase angle decreases monotonically; that is, the second change trend is that the impedance modulus |Z| increases monotonically, the real part Zre increases monotonically, and the phase angle decreases monotonically.

[0091] Therefore, based on the received EIS parameters and the EIS parameters received in the historical battery internal short circuit identification cycle, the impedance modulus |Z| change trend, the real part Zre change trend and the phase angle θ change trend can be determined respectively, and the impedance modulus change trend is compared with the impedance modulus change trend in the second change trend to obtain a first comparison result, and the real part change trend is compared with the real part change trend in the second change trend to obtain a second comparison result, and the phase angle change trend is compared with the phase angle change trend in the second change trend to obtain a third comparison result. If any comparison result among the first comparison result, the second comparison result and the third comparison result is inconsistent, the battery module is determined to be internally short-circuited. In specific implementation, it can also be set that when a battery module is determined to be internally short-circuited by N consecutive preset detections, it is determined to be internally short-circuited again, and N is a positive integer.

[0092] In this way, because the law of parameter change only requires the relative accuracy of EIS measurement to meet the requirements, no absolute accuracy is required, which solves the problem that the commonly used battery model fitting fails due to the inaccurate absolute accuracy of EIS measurement, and improves the accuracy of internal short circuit identification.

[0093] In specific implementation, after determining that the battery module has an internal short circuit, the server can also determine the internal short circuit severity level of the battery module based on the EIS parameters of the battery module and the EIS parameter range of the battery module corresponding to the pre-set internal short circuit severity levels; and then issue an early warning to the battery module based on the internal short circuit severity level.

[0094] In specific implementation, different internal short circuit severity levels and their corresponding EIS parameter ranges can be pre-set through a large amount of experimental data or historical records. For example, the preset internal short circuit severity levels are slight, moderate and severe. EIS tests are performed on battery modules with different degrees of internal short circuits, and their EIS parameters are recorded. According to the recorded parameters, the variation rules of EIS parameters under different internal short circuit severity levels are summarized. For example, an internal short circuit severity mapping table is established. When it is determined that the battery module is internally shorted, the EIS parameters (impedance modulus |Z|, real part Zre, imaginary part Zim and phase angle θ) of the battery module are matched with the EIS parameter ranges corresponding to each internal short circuit severity level pre-set in the internal short circuit severity mapping table, and the impedance modulus is checked to see whether it falls within the range of a certain severity level, the phase angle is checked to see whether it falls within the range of a certain severity level, the real part is checked to see whether it falls within the range of a certain severity level, and the imaginary part is checked to see whether it falls within the range of a certain severity level. Then, a comprehensive evaluation is performed. If most of the parameters meet the range of a certain target severity level (for example, 3 parameters or more), the internal short circuit severity level of the battery module can be confirmed to be the target severity level. Afterwards, the server triggers the corresponding early warning mechanism according to the determined severity level of the internal short circuit.

[0095] For example, different severity levels can trigger different levels of alarms, for example: minor internal short circuit: a low-level warning is issued, and regular monitoring is recommended; moderate internal short circuit: an intermediate warning is issued, and it is recommended to check as soon as possible; severe internal short circuit: a high-level alarm is issued, and immediate measures are taken, such as stopping charging / discharging, isolating battery modules, etc. The specific settings can be made by technical personnel, and this application is not limited.

[0096] In this way, the server can not only identify whether there is an internal short circuit in the battery module, but also further determine the severity of the internal short circuit and issue appropriate warnings based on this. This method improves the battery management system's response speed and accuracy to potential faults, helps to take preventive measures in a timely manner, and ensures the safe operation of the system.

[0097] In some embodiments, the excitation unit includes a DC / AC module and a switch matrix. Figure 2 , is a schematic diagram of the architecture of another battery internal short circuit identification system provided in an embodiment of the present application, wherein;

[0098] The DC / AC module is used to send a target output frequency to the BMS after receiving an excitation request, and after receiving a reception response, convert the direct current into a target excitation current, and control the switch matrix to conduct a path between the DC / AC module and the battery module;

[0099] In specific implementation, the DC / AC module sends the target output frequency to the BMS through the communication interface to inform it that it is ready for the excitation operation. When the DC / AC module receives the receiving response from the BMS, it indicates that the BMS is ready for the next operation. At this time, the DC / AC module can start to convert the DC power into the target excitation current. The inverter inside the DC / AC module converts the DC power from the DC bus into the target excitation current, and controls the switch matrix to turn on the path between the DC / AC module and the battery module, ensuring that the target excitation current can be smoothly transmitted to the battery module.

[0100] In a specific implementation, if multiple BMSs simultaneously send excitation requests to the DC / AC module, the DC / AC module determines the priorities of the multiple BMSs based on the preset priorities of the battery modules; determines the target BMS based on the priorities of the multiple BMSs; wherein the target BMS is the BMS with the highest priority among the current BMSs, and the current BMS includes the BMS among the multiple BMSs that has not received the target output frequency; sends the target output frequency to the target BMS, and after receiving the receiving response, converts the direct current into the target excitation current, and controls the switch matrix to conduct the path between the DC / AC module and the battery module corresponding to the target BMS; when it is determined that the preset first disconnection condition is met, controls the switch matrix to disconnect the path between the DC / AC module and the battery module corresponding to the target BMS, and returns to the step of determining the target BMS based on the priorities of the multiple BMSs.

[0101] For example, BMS1, BMS2 and BMS3 send excitation requests to the DC / AC module at the same time, where BMS1 corresponds to battery module 1, BMS2 corresponds to battery module 2 and BMS3 corresponds to battery module 3. The DC / AC module can determine the priority of each BMS based on the identification of the battery module in the excitation request sent by each BMS and the preset priority of the battery module. For example, the preset priority of the battery module is battery module 3 higher than battery module 2 higher than battery module 1. Therefore, the priority of the BMS is BMS3 higher than BMS2 higher than BMS1.

[0102] Then, the BMS with the highest priority is selected from multiple BMSs as the target BMS, that is, BMS3, and the target output frequency is sent to the target BMS. After receiving the receiving response, the DC power is converted into the target excitation current, and the switch matrix is ​​controlled to conduct the path between the DC / AC module and the battery module corresponding to the target BMS; when it is determined that the preset first disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module corresponding to the target BMS, and the step of determining the target BMS based on the priority of multiple BMSs is returned, that is, BMS2 is determined as the target BMS next time, and the above steps are repeated until BMS1 is determined as the target BMS and the above steps are executed. Among them, the preset first disconnection condition can be to determine that the excitation of the target BMS is completed, such as setting the excitation time. When the time is reached, it is determined that the preset first disconnection condition is met. The specific setting can be made by the technician, and this application is not limited.

[0103] In practical applications, each output frequency usually needs to be maintained for more than 3 excitations. Therefore, the DC / AC module can record the number of excitations after applying the target excitation current to the battery module corresponding to the target BMS. If the number of excitations is less than the preset number of excitations, assuming that the preset number of excitations is 3 times, after determining that the preset time interval has been reached, the target excitation current is applied to the battery module again; if the number of excitations is equal to the preset number of excitations, the number of excitations is cleared and when it is determined that the preset second disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module corresponding to the target BMS, wherein the preset second disconnection condition can also be that the time reaches the preset time interval.

[0104] In a specific implementation, the target output frequency sent by the DC / AC module may be multiple, that is, the DC / AC module may determine multiple output frequencies corresponding to the excitation request from a preset correspondence based on the excitation request; wherein the preset correspondence may be a pre-set correspondence between the output frequencies corresponding to each battery module, and the multiple output frequencies corresponding to the battery module may be determined based on the preset correspondence.

[0105] Then, the target output frequency is sent to the BMS, and after receiving the receiving response, the direct current is converted into the target excitation current, and the switch matrix is ​​controlled to conduct the path between the DC / AC module and the battery module, wherein the target output frequency is the highest output frequency among the current output frequencies, and the current output frequency includes the output frequency that is not sent among the multiple output frequencies. When it is determined that the preset third disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module, and the step of sending the target output frequency to the BMS is returned.

[0106] For example, it is determined that there are three output frequencies corresponding to the battery module, namely frequency 1, frequency 2 and frequency 3, and from high frequency to low frequency, they are frequency 3, frequency 2 and frequency 1 respectively, then the target output frequency sent to the BMS for the first time is frequency 3, and after receiving the receiving response, the direct current is converted into the target excitation current, and the switch matrix is ​​controlled to conduct the path between the DC / AC module and the battery module. When it is determined that the preset third disconnection condition is met, wherein the preset third disconnection condition, such as the time reaching the preset time interval, controls the switch matrix to disconnect the path between the DC / AC module and the battery module, and determines the output frequency with the highest frequency among the multiple output frequencies that have not been sent, That is, frequency 2, then frequency 2 is sent to the BMS, and after receiving the receiving response, the direct current is converted into the target excitation current, and the switch matrix is ​​controlled to conduct the path between the DC / AC module and the battery module. When it is determined that the preset third disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module, and the last output frequency, that is, frequency 1, is sent to the BMS. After receiving the receiving response, the direct current is converted into the target excitation current, and the switch matrix is ​​controlled to conduct the path between the DC / AC module and the battery module. When it is determined that the preset third disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module.

[0107] In this way, each output frequency is maintained for a preset number of excitations, which can ensure that the BMS can collect the complete cycle of excitation and the voltage response of the battery module.

[0108] The BMS is also used to send a reception response to the DC / AC module after receiving the target output frequency.

[0109] After receiving the target output frequency, the BMS sends a receiving response to the DC / AC module to inform the DC / AC module that the target output frequency has been received.

[0110] The BMS is specifically used to determine a collection frequency based on a target output frequency, and to collect a target excitation current and a voltage response of the battery module based on the target excitation current based on the collection frequency, wherein the target excitation current is collected by the BMS through a current sensor.

[0111] In specific implementation, when the EIS test is not performed, in order to reduce the load rate of the BMS microcontroller unit (MCU), the current and voltage collection frequency is generally about 100ms, but the EIS excitation frequency range is 0.1-5kHz. Therefore, after confirming the target output frequency of the DC / AC, the BMS needs to adjust the collection frequency of the battery module voltage and current to meet the Shannon sampling frequency Fs ≥ 2FH (where Fs is the sampling frequency and FH is the highest frequency of the signal), that is, the sampling frequency (Fs) should be at least twice the highest signal frequency (FH).

[0112] Please refer to Figure 3 , Figure 3 A flowchart of a method for identifying a short circuit in a battery provided in an embodiment of the present application, the method is applied to Figure 1 In the BMS of the battery internal short circuit identification system, the method includes the following steps.

[0113] In step 301, for the BMS in any battery cell, when the BMS determines that the battery module corresponding to the BMS meets the electrochemical impedance spectroscopy (EIS) test conditions, the BMS sends an excitation request to the excitation unit, so that after receiving the excitation request, the excitation unit converts direct current into a target excitation current and sends the target excitation current to the battery module, wherein the direct current is obtained by converting alternating current through a switching power supply.

[0114] During specific implementation, the BMS monitors the status of the battery module; determines that the continuous static time of the battery module meets the preset static time, and determines that the interval between the current moment and the last time the EIS parameters of the battery module were obtained meets the preset interval time, then determines that the battery module meets the electrochemical impedance spectroscopy EIS test conditions.

[0115] In step 302 , after the battery module receives the target excitation current, the BMS collects the target excitation current and a voltage response of the battery module generated based on the target excitation current.

[0116] In a specific implementation, the excitation unit includes a DC / AC module and a switch matrix. After receiving an excitation request, the DC / AC module sends a target output frequency to the BMS, and after receiving a reception response, converts direct current into the target excitation current and controls the switch matrix to conduct the path between the DC / AC module and the battery module.

[0117] The BMS, after receiving the target output frequency, sends a reception response to the DC / AC module.

[0118] The BMS determines a collection frequency based on a target output frequency, and collects a target excitation current and a voltage response generated by the battery module based on the target excitation current based on the collection frequency, wherein the target excitation current is collected by the BMS through a current sensor.

[0119] In step 303, the BMS calculates the EIS parameters of the battery module based on the target excitation current and voltage response, and sends the EIS parameters of the battery module to the server, so that after the server receives the EIS parameters of the battery module, after determining that the battery module has reached the internal short circuit identification cycle, it determines whether the battery module has an internal short circuit based on the received EIS parameters.

[0120] For specific implementation, please refer to Figure 4 , Figure 4 A flow chart of a server determining a short circuit in a battery is provided in an embodiment of the present application. The method includes the following steps.

[0121] In step 401, after determining that the internal short circuit identification cycle of the battery module has arrived, the server determines a first change trend of the EIS parameter based on the received EIS parameter.

[0122] In a specific implementation, the EIS parameters include an impedance modulus, a real part, and a phase angle. The server determines the impedance modulus change trend, the real part change trend, and the phase angle change trend based on the received EIS parameters.

[0123] In specific implementation, by comparing historical data with current data under the same working condition and EIS at the characteristic frequency, the impedance modulus change trend, real part change trend and phase angle change trend can be determined.

[0124] In step 402, the server identifies an internal short circuit of the battery module based on the first change trend and a preset second change trend, wherein the second change trend is a change trend of an EIS parameter corresponding to when the battery module is not internally short-circuited.

[0125] In specific implementation, according to experimental data, as the number of battery cell cycles increases, at the same (remaining available power) SOC and temperature at the characteristic frequency, the impedance modulus |Z| increases monotonically, the real part Zre increases monotonically, and the phase angle decreases monotonically; that is, the second change trend is that the impedance modulus |Z| increases monotonically, the real part Zre increases monotonically, and the phase angle decreases monotonically.

[0126] In a specific implementation, the server compares the impedance modulus change trend with the impedance modulus change trend in the second change trend to obtain a first comparison result, and

[0127] Compare the real part variation trend with the real part variation trend in the second variation trend to obtain a second comparison result, and

[0128] The phase angle variation trend is compared with the phase angle variation trend in the second variation trend to obtain a third comparison result.

[0129] In step 403 , the server determines whether the battery module is internally short-circuited based on the identification result. If so, the server proceeds to step 404 ; otherwise, the server proceeds to step 406 .

[0130] In a specific implementation, if any comparison result among the first comparison result, the second comparison result and the third comparison result is inconsistent, it is determined that the battery module is internally short-circuited; otherwise, the battery is not internally short-circuited.

[0131] In step 404 , the server determines the internal short circuit severity level of the battery module based on the EIS parameter of the battery module and the preset EIS parameter range of the battery module corresponding to each internal short circuit severity level.

[0132] In specific implementation, different internal short circuit severity levels and their corresponding EIS parameter ranges can be pre-set through a large amount of experimental data or historical records. For example, the preset internal short circuit severity levels are mild, moderate and severe. EIS tests are performed on battery modules with different degrees of internal short circuits, and their EIS parameters under different working conditions are recorded. Based on the recorded parameters, the change patterns of EIS parameters under different internal short circuit severity levels are summarized, for example, an internal short circuit severity mapping table is established.

[0133] Then, when it is determined that the battery module is internally short-circuited, the EIS parameters (impedance modulus |Z|, real part Zre, imaginary part Zim, and phase angle θ) of the battery module are matched with the EIS parameter ranges corresponding to each internal short circuit severity level pre-set in the internal short circuit severity mapping table, and the impedance modulus is checked to see whether it falls within a certain severity level range, the phase angle is checked to see whether it falls within a certain severity level range, the real part is checked to see whether it falls within a certain severity level range, and the imaginary part is checked to see whether it falls within a certain severity level range. Then, after a comprehensive evaluation, if most of the parameters meet the range of a certain target severity level (for example, 3 parameters or more), it can be confirmed that the internal short circuit severity level of the battery module is the target severity level.

[0134] In step 405, the server issues an early warning to the battery module based on the severity level of the internal short circuit.

[0135] In step 406, the process ends.

[0136] During specific implementation, after the process is finished, return to step 401.

[0137] Based on the same technical concept, the embodiment of the present application also provides a storage medium, when the computer program in the storage medium is executed by the processor of the BMS, the BMS can execute the above-mentioned battery internal short circuit identification method. Optionally, the storage medium can be a non-temporary computer-readable storage medium, for example, the non-temporary computer-readable storage medium can be a ROM, a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device, etc.

[0138] In an exemplary embodiment, the BMS of the present application may include at least one processor and a memory communicatively connected to the at least one processor, wherein the memory stores a computer program executable by the at least one processor, and when the computer program is executed by the at least one processor, the at least one processor may execute the steps of any battery internal short circuit identification method provided in the embodiments of the present application.

[0139] In an exemplary embodiment, a computer program product is also provided. When the computer program product is executed by a BMS, the BMS can implement any exemplary method provided in the present application.

[0140] Furthermore, the computer program product may use any combination of one or more readable media. The readable medium may be a readable signal medium or a readable storage medium. The readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples (non-exhaustive list) of readable storage media include: an electrical connection with one or more wires, a portable disk, a hard disk, a RAM, a ROM, an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a compact disk read only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0141] The program product for identifying short circuits in batteries in the embodiments of the present application may use a CD-ROM and include program code, and may be run on a computing device. However, the program product of the present application is not limited thereto, and in this document, a readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, apparatus, or device.

[0142] The readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, wherein the readable program code is carried. Such propagated data signals may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The readable signal medium may also be any readable medium other than a readable storage medium, which may send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0143] The program code contained on the readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, radio frequency (RF), etc., or any suitable combination of the foregoing.

[0144] The technical solution provided by the present application is introduced in detail above. The principles and implementation methods of the present application are explained by using specific examples in the present application. The description of the above embodiments is only used to help understand the method of the present application and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present application.

[0145] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that include computer-usable program code.

[0146] The present application is described with reference to the flowcharts and / or block diagrams of the methods, apparatus (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0147] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0148] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0149] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A battery internal short circuit identification system, characterized in that: The system comprises: a switching power supply, an excitation unit, a plurality of battery units, and a server, wherein any battery unit comprises a battery module and a battery management system BMS; The switching power supply is used to convert alternating current into direct current for powering the communication equipment; For any BMS, the BMS is used to send an excitation request to the excitation unit when it is determined that the battery module meets the electrochemical impedance spectroscopy (EIS) test conditions, and after the battery module receives the target excitation current, collect the target excitation current and the voltage response of the battery module based on the target excitation current, calculate the EIS parameters of the battery module based on the target excitation current and send the EIS parameters of the battery module to the server; The excitation unit is configured to, after receiving the excitation request, convert the direct current into the target excitation current and send the target excitation current to the battery module; The server is used to receive the EIS parameters of the battery module, and after determining that a battery internal short circuit identification cycle of the battery module has arrived, determine whether the battery module has an internal short circuit based on the received EIS parameters.

2. The system according to claim 1, characterized in that The excitation unit includes a DC / AC module and a switch matrix, wherein: The DC / AC module is used to send a target output frequency to the BMS after receiving the excitation request, and after receiving a reception response, convert the direct current into the target excitation current, and control the switch matrix to conduct a path between the DC / AC module and the battery module; The BMS is further configured to send the receiving response to the DC / AC module after receiving the target output frequency; The BMS is specifically used to determine a collection frequency based on the target output frequency, and to collect the target excitation current and a voltage response of the battery module based on the target excitation current based on the collection frequency, wherein the target excitation current is collected by the BMS through a current sensor.

3. The system according to claim 2, characterized in that If multiple BMSs send excitation requests to the DC / AC module at the same time, the DC / AC module is further configured to: Determining priorities of the plurality of BMSs based on preset priorities of the battery modules; Based on the priorities of the multiple BMSs, determining a target BMS; wherein the target BMS is a BMS with the highest priority among the current BMSs, and the current BMS includes a BMS among the multiple BMSs that has not received a target output frequency; sending the target output frequency to the target BMS, and after receiving a reception response, converting the direct current into the target excitation current, and controlling the switch matrix to conduct a path between the DC / AC module and the battery module corresponding to the target BMS; When it is determined that the preset first disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module corresponding to the target BMS, and the process returns to the step of determining the target BMS based on the priority of the multiple BMSs.

4. The system according to claim 3, characterized in that The DC / AC module is also used for: After applying a target excitation current to the battery module corresponding to the target BMS, recording the number of excitations; If the number of excitations is less than a preset number of excitations, after determining that a preset time interval has been reached, applying the target excitation current to the battery module again; If the number of excitations is equal to the preset number of excitations, the number of excitations is reset to zero and when it is determined that the preset second disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module corresponding to the target BMS.

5. The system according to claim 2, characterized in that The DC / AC module is specifically used for: Based on the excitation request, determining a plurality of output frequencies corresponding to the excitation request from a preset corresponding relationship; Sending a target output frequency to the BMS, and after receiving a receiving response, converting the direct current into the target excitation current, and controlling the switch matrix to conduct the path between the DC / AC module and the battery module, wherein the target output frequency is the highest output frequency among the current output frequencies, and the current output frequency includes the output frequency that is not sent among the multiple output frequencies; When it is determined that the preset third disconnection condition is met, the switch matrix is ​​controlled to disconnect the path between the DC / AC module and the battery module, and the process returns to the step of sending the target output frequency to the BMS.

6. The system according to claim 1, wherein: The BMS is specifically used for: Monitoring the status of the battery module; If it is determined that the continuous static time of the battery module meets the preset static time, and if it is determined that the interval between the current moment and the moment when the EIS parameters of the battery module were last obtained meets the preset interval time, then it is determined that the battery module meets the electrochemical impedance spectroscopy EIS test conditions.

7. The system according to any one of claims 1 to 6, characterized in that: The server is specifically used for: Determining a first change trend of the EIS parameter based on the received EIS parameter and the EIS parameter received during a historical battery internal short circuit identification cycle; Based on the first change trend and a preset second change trend, an internal short circuit of the battery module is identified, wherein the second change trend is a change trend of an EIS parameter corresponding to when the battery module is not internally short-circuited.

8. The system according to claim 7, characterized in that The EIS parameters include impedance modulus, real part and phase angle, and the server is specifically used for: Based on the received EIS parameters and the EIS parameters received in the historical battery internal short circuit identification cycle, respectively determine the impedance modulus change trend, the real part change trend and the phase angle change trend; Comparing the impedance modulus change trend with the impedance modulus change trend in the second change trend to obtain a first comparison result, and comparing the real part change trend with the real part change trend in the second change trend to obtain a second comparison result, and comparing the phase angle change trend with the phase angle change trend in the second change trend to obtain a third comparison result; If any comparison result among the first comparison result, the second comparison result and the third comparison result is inconsistent, it is determined that the battery module is internally short-circuited.

9. The system according to claim 8, characterized in that The server is also used to: After determining that the battery module is internally short-circuited, determining the internal short-circuit severity level of the battery module based on the EIS parameter of the battery module and the EIS parameter range of the battery module corresponding to each preset internal short-circuit severity level; Based on the internal short circuit severity level, an early warning is issued to the battery module.

10. A method for identifying a short circuit in a battery, characterized in that: Applied to the battery internal short circuit identification system as claimed in any one of claims 1 to 9, the method comprising: For the BMS in any battery unit, when determining that the battery module corresponding to the BMS meets the electrochemical impedance spectroscopy EIS test conditions, the BMS sends an excitation request to the excitation unit, so that the excitation unit converts direct current into a target excitation current after receiving the excitation request, and sends the target excitation current to the battery module, wherein the direct current is obtained by converting alternating current by a switching power supply; After the battery module receives the target excitation current, the BMS collects the target excitation current and a voltage response of the battery module generated based on the target excitation current; The BMS calculates the EIS parameters of the battery module based on the target excitation current and the voltage response, and sends the EIS parameters of the battery module to a server, so that after the server receives the EIS parameters of the battery module and determines that a battery internal short circuit identification cycle of the battery module has been reached, it determines whether the battery module has an internal short circuit based on the received EIS parameters.

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