A method for monitoring insulation of a battery pack and an apparatus for monitoring insulation of a battery pack

Abstract

This application provides an insulation monitoring method and device for a battery pack, applicable to a battery pack comprising multiple batteries, each battery having a third electrode on its casing. The method obtains multiple first voltage values ​​by acquiring the first voltage value between the electrode and the third electrode of each battery in the target battery pack. From these multiple first voltage values, a first target voltage value with the largest value is determined. Based on a preset voltage range between the electrode and the third electrode when the battery is in different risk states, a target voltage range is determined. The endpoint voltage values ​​of the preset voltage range are determined based on a correlation between the insulation impedance between the electrode and the third electrode and the battery casing voltage. The target risk state of the target battery pack is determined based on the risk state corresponding to the target voltage range. This application can detect the risk state of the battery pack in real time, facilitating timely early warning of battery risks and thus improving battery life and safety.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to an insulation monitoring method and a battery pack insulation monitoring device. Background Technology

[0002] Currently, batteries are widely used in various electronic products. A battery mainly consists of a casing (or aluminum-plastic film outer packaging) and a cell, with the cell containing a positive and a negative electrode. During use, an external circuit is connected to the positive and negative electrodes of the battery for charging and discharging. Specifically, batteries are often used in groups; the larger the group, the worse the insulation performance.

[0003] In existing technologies, batteries with poor insulation are mainly screened and rejected by testing the side voltage or side resistance during the manufacturing process. However, after the batteries are assembled, complex operating conditions can still cause the cells to expand and contract during charging and discharging. This may cause the insulating film on the battery surface to crack, resulting in poor insulation between the electrolyte and the casing (or aluminum-plastic film outer packaging). In severe cases, a current channel may form between the casing (or aluminum-plastic film outer packaging) and the electrolyte, thereby affecting the battery pack's lifespan and safety. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide an insulation monitoring method and a battery pack insulation monitoring device, which can measure the voltage value between the electrode and the third electrode in real time through the lead-out third electrode, and through the corresponding control processing strategy, can detect the risk status of the battery pack in real time, which helps to provide timely warning of the battery pack, thereby improving the life and safety of the battery pack.

[0005] In a first aspect, embodiments of this application provide an insulation monitoring method for a battery pack, applicable to a battery pack comprising multiple batteries, each battery comprising two electrodes, the voltage between the two electrodes being the battery voltage, and each battery casing further comprising a third electrode, the third electrode being conductive to the casing; the insulation monitoring method includes:

[0006] Collect the first voltage value between the electrode of each battery in the target battery pack and the third electrode to obtain multiple first voltage values ​​corresponding to the target battery pack;

[0007] The first target voltage value with the largest value is determined from the plurality of first voltage values;

[0008] Based on the preset voltage range between the electrodes and the third electrode when the battery is under different risk conditions, the target voltage range to which the first target voltage value belongs is determined; wherein, the endpoint voltage value of the preset voltage range is determined based on the correlation between the insulation resistance between the electrodes and the third electrode and the battery casing voltage.

[0009] The target risk state of the target battery pack is determined based on the risk state corresponding to the target voltage range.

[0010] In one optional embodiment of this application, the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage is fitted through the following steps:

[0011] Multiple insulation impedance samples between the electrode and the third electrode were collected at different times, as well as battery casing voltage samples corresponding to each insulation impedance sample;

[0012] Determine the average insulation resistance and the average battery casing voltage corresponding to the average insulation resistance;

[0013] By fitting the average insulation resistance and the average battery casing voltage, the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage is obtained.

[0014] In one optional embodiment of this application, the endpoint voltage value of the preset voltage range is determined by the following steps:

[0015] Obtain the critical values ​​of insulation impedance of the battery under different risk states; wherein, the risk states include no risk state, low risk state, critical risk state, and high risk state;

[0016] Based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage, the endpoint voltage value corresponding to the critical value of the insulation resistance is determined.

[0017] In one optional embodiment of this application, the method further includes:

[0018] The second voltage value between the electrode and the third electrode of each battery in the battery pack is collected to obtain multiple second voltage values ​​corresponding to the battery pack.

[0019] The second target voltage value with the largest value is determined from the plurality of second voltage values;

[0020] The battery pack whose second target voltage value is not greater than the risk potential threshold is identified as the target battery pack.

[0021] In one optional embodiment of this application, the risk potential threshold refers to the endpoint voltage value corresponding to the critical value of insulation resistance when the battery is in a risk-free state, which is determined based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage.

[0022] In one optional embodiment of this application, the method further includes:

[0023] If the target battery pack is in a critical risk state, the number of times the target battery pack is detected is increased.

[0024] If the target battery pack is in a high-risk state, the target battery pack is locked through a control loop to stop its use.

[0025] In one optional embodiment of this application, the step of determining the target risk state of the target battery pack based on the risk state corresponding to the target voltage range includes:

[0026] If the risk state corresponding to the target voltage range to which the first target voltage value belongs is a critical risk state, then the battery corresponding to the first target voltage value is detected multiple times in succession to see if it is the same battery.

[0027] If so, the target battery pack is determined to be in a critical risk state.

[0028] In one optional embodiment of this application, the step of acquiring a first voltage value between the electrode of each battery in the target battery pack and the third electrode includes:

[0029] When an instruction is received to collect the first voltage value between the electrode of each battery in the target battery pack and the third electrode, the first voltage value between the electrode of each battery in the target battery pack and the third electrode is collected after a preset time delay.

[0030] In one optional embodiment of this application, the method further includes:

[0031] Collect ambient temperature data and current flowing through the target battery pack;

[0032] The state of charge of the target battery pack is determined based on the determined first target voltage value and the current.

[0033] The ambient temperature data and the determined state of charge are input into a pre-trained battery detection model, which outputs the risk state of the target battery pack to verify whether the risk state of the target battery pack is the same as the target risk state.

[0034] Secondly, embodiments of this application also provide an insulation monitoring device for a battery pack, the insulation monitoring device comprising: a data acquisition module and a data processing module; the data acquisition module comprising a plurality of data acquisition units, each acquisition unit being connected to the electrode and the third electrode of one of the batteries in the target battery pack respectively; the data acquisition module is also connected to the data processing module;

[0035] The data acquisition module is used to acquire the first voltage value between the electrode of each battery in the target battery pack and the third electrode, and obtain multiple first voltage values ​​corresponding to the target battery pack.

[0036] The data processing module is used to determine the first target voltage value with the largest value from the plurality of first voltage values; determine the target voltage range to which the first target voltage value belongs based on a preset voltage range between the electrode and the third electrode when the battery is in different risk states; wherein, the endpoint voltage value of the preset voltage range is determined based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage; and determine the target risk state of the target battery pack based on the risk state corresponding to the target voltage range.

[0037] Thirdly, embodiments of this application also provide an electronic device, including: a processor, a memory, and a bus. The memory stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the memory via the bus. When the machine-readable instructions are executed by the processor, the steps of the battery pack insulation monitoring method described above are performed.

[0038] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the battery pack insulation monitoring method described above.

[0039] The battery pack insulation monitoring method and device provided in this application, by setting a third electrode on the battery casing, can measure the voltage value between the electrode and the third electrode in real time during the battery assembly process to obtain real-time insulation information of the battery; by determining the relationship between the determined first target voltage value and the preset voltage range, the target voltage range to which the first target voltage value belongs is determined, and then the target risk state of the target battery pack is determined according to the risk state corresponding to the target voltage range, so as to achieve the purpose of real-time detection of the risk state of the battery pack. The endpoint voltage value of the preset voltage range is determined according to the correlation between the insulation impedance between the electrode and the third electrode and the voltage of the battery casing, so as to obtain a more accurate preset voltage range, thereby enabling real-time detection of the risk state of the battery pack, which helps to provide timely warnings for the battery pack and improve the life and safety of the battery pack.

[0040] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0041] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0042] Figure 1 This is a schematic diagram of the structure of a battery provided in an embodiment of this application;

[0043] Figure 2 A flowchart illustrating an insulation monitoring method for a battery pack provided in an embodiment of this application;

[0044] Figure 3 A schematic diagram of the fitting curve corresponding to the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage provided in the embodiments of this application;

[0045] Figure 4 A flowchart illustrating another battery pack insulation monitoring method provided in this application embodiment;

[0046] Figure 5 This is a schematic diagram of the structure of an insulation monitoring device for a battery pack provided in an embodiment of this application. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0048] First, the applicable application scenarios of this application will be introduced. Currently, batteries are widely used in various electronic products. A battery mainly consists of a casing (or aluminum-plastic film outer packaging) and a cell, where the cell includes a positive electrode and a negative electrode. During use, an external circuit is connected to the positive and negative electrodes of the battery for charging and discharging. Specifically, batteries are often used in groups; the larger the group size, the worse the insulation performance.

[0049] In existing technologies, batteries with poor insulation are mainly screened and rejected by testing the side voltage or side resistance during the manufacturing process. However, after the batteries are assembled, complex operating conditions can still cause the cells to expand and contract during charging and discharging. This may cause the insulating film on the battery surface to crack, resulting in poor insulation between the electrolyte and the casing (or aluminum-plastic film outer packaging). In severe cases, a current channel may form between the casing (or aluminum-plastic film outer packaging) and the electrolyte, thereby affecting the battery pack's lifespan and safety.

[0050] Based on this, the present application provides an insulation monitoring method and a battery pack insulation monitoring device, which can measure the voltage value between the electrode and the third electrode in real time through the led-out third electrode, and through the corresponding control processing strategy, can detect the risk status of the battery pack in real time, which helps to provide timely warnings for the battery pack, thereby improving the life and safety of the battery pack.

[0051] This application provides an insulation monitoring method for a battery pack, which is applied to a battery pack including multiple batteries. Each battery includes two electrodes, and the voltage between the two electrodes is the battery voltage. Each battery also has a third electrode on its casing, and the third electrode is connected to the casing.

[0052] Here, since the positive and negative terminals of the battery are not conductive to the casing under normal circumstances, it is inconvenient to measure the voltage between the positive and negative terminals of the battery and the casing when multiple batteries are grouped together. Therefore, a third terminal is brought out on the battery casing to solve the above-mentioned problem. By measuring the voltage between the positive or negative terminal of the battery and the third terminal, the purpose of monitoring the potential risk status of the battery pack can be achieved.

[0053] For example, such as Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of a battery provided in an embodiment of this application. Figure 1 As shown, the battery 100 includes a casing 101 and a cell 102. The cell 102 has two electrodes, namely a positive electrode 103 and a negative electrode 104. The voltage between the positive electrode 103 and the negative electrode 104 is the battery voltage. It also includes a third electrode 105, which is independently disposed on the battery casing 101 (or aluminum-plastic film outer packaging). The third electrode 105 is connected to the casing 101 (or connected to the aluminum layer in the middle of the aluminum-plastic film).

[0054] Optionally, the connection between the third electrode 105 and the housing 101 is achieved by laser welding or hot melt adhesive. For example, the third electrode 105 is a metal conductor, preferably made of aluminum; the metal conductor can be sheet-like or wire-like. Optionally, the third electrode 105 can be located between the positive electrode 103 and the negative electrode 104, or it can be located on a single side; wherein the battery can be a lithium battery or a sodium battery.

[0055] Specifically, there is an insulation resistance between the positive terminal 103 and the third terminal 105 of the battery, or between the negative terminal 104 and the third terminal 105. This insulation resistance has an extremely high surface insulation resistance value; the higher the insulation resistance, the more stable and safe the battery. Furthermore, because there is a protective circuit between the negative terminal and the casing, they are not completely insulated. Since there is a voltage between the positive and negative terminals, there will also be a voltage between the positive terminal and the casing.

[0056] Please see Figure 2 , Figure 2 This is a flowchart illustrating an insulation monitoring method for a battery pack provided in an embodiment of this application. Figure 2 As shown in the embodiments of this application, the insulation monitoring method includes:

[0057] S201. Collect the first voltage value between the electrode and the third electrode of each battery in the target battery pack to obtain multiple first voltage values ​​corresponding to the target battery pack.

[0058] In step S201, the electrodes of the battery may include a positive electrode or a negative electrode. That is, in step S201, the first voltage value between the positive electrode and the third electrode of each battery in the target battery pack can be collected, or the first voltage value between the negative electrode and the third electrode of each battery in the target battery pack can be collected. The battery pack can be composed of multiple batteries connected in series or in parallel, and thus, multiple first voltage values ​​can be collected to obtain multiple first voltage values ​​corresponding to the target battery pack.

[0059] Preferably, the battery electrode is selected as the positive electrode. Because the potential of the aluminum casing or aluminum-plastic film outer packaging is higher than that of the negative electrode, if there is poor insulation between the negative electrode and the casing, the insulation between the electrolyte and the casing will crack, and the aluminum casing (or aluminum-plastic film outer packaging) will undergo a reduction reaction to form a Li-Al alloy. The Li-Al alloy is very fragile and will form small pores. If external moisture enters through these pores, it will react with the electrolyte to produce gas, leading to a shortened battery life and, in severe cases, battery leakage. Poor insulation between the positive electrode and the casing only causes an oxidation reaction and does not affect the lithium battery life. Furthermore, collecting the first voltage value between the positive and third electrodes of the battery to determine the risk state of the target battery pack not only does not affect the battery life but also avoids the impact of various factors caused by poor insulation on data processing, thereby improving the accuracy of data processing. Therefore, in this embodiment, the insulation resistance between the electrode and the third electrode refers to the insulation resistance between the positive electrode and the third electrode, and the battery casing voltage refers to the voltage between the positive electrode and the casing.

[0060] In an optional embodiment, step S201 further includes:

[0061] When an instruction is received to collect the first voltage value between the electrode and the third electrode of each battery in the target battery pack, the first voltage value between the electrode and the third electrode of each battery in the target battery pack is collected after a preset time delay.

[0062] Here, the first voltage value between the electrode and the third electrode of each battery in the target battery pack is collected after a preset delay time. In a specific embodiment, the delay time is preferably 5-10 seconds.

[0063] In this embodiment of the application, the purpose of the delay is to prevent misjudgment caused by sampling fluctuations or interference factors. By delaying the acquisition by a preset time, a relatively stable voltage value can be obtained, making the acquired data more accurate. At the same time, it can also play an early warning role, thereby preventing misjudgment and misresponse.

[0064] S202. Determine the first target voltage value with the largest value from multiple first voltage values.

[0065] In step S202, since the battery pack includes multiple batteries, each battery corresponds to a first voltage value, the first voltage value with the largest value is selected from the multiple first voltage values ​​as the first target voltage value.

[0066] For example, a bubble sort method can be used to determine the first target voltage value with the largest value from multiple first voltage values.

[0067] S203. Determine the target voltage range to which the first target voltage value belongs based on the preset voltage range between the electrode and the third electrode when the battery is in different risk states; wherein, the endpoint voltage value of the preset voltage range is determined based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage.

[0068] In step S203, multiple insulation impedance samples and corresponding battery casing voltage samples are obtained through multiple sets of experiments. By fitting the obtained insulation impedance samples and battery casing voltage samples, the correlation between insulation impedance and battery casing voltage can be obtained.

[0069] Specifically, step S203 fits the relationship between the insulation resistance between the electrode and the third electrode and the battery casing voltage through the following steps:

[0070] Step 2031: Obtain multiple insulation impedance samples between the electrode and the third electrode collected at different times, as well as the battery casing voltage sample corresponding to each insulation impedance sample.

[0071] Here, multiple insulation impedance samples between the electrodes and the third electrode of a battery at different times are obtained, along with the battery casing voltage sample corresponding to each insulation impedance sample. This operation is relatively simple and easy to collect.

[0072] Specifically, to enrich the collected data samples, multiple insulation resistance samples between the electrodes and the third electrode of the battery under different risk states can be collected, along with the battery casing voltage sample corresponding to each insulation resistance sample. Optionally, the risk states include, but are not limited to, risk-free state, low-risk state, critical-risk state, and high-risk state. Optionally, the batteries under different risk states can be the same battery or different batteries.

[0073] Optionally, the timing for collecting insulation impedance samples and battery casing voltage samples can be determined based on a pre-set inspection frequency. The inspection frequency refers to the detection frequency of the insulation testing device, such as once every six hours. For example, multiple insulation impedance samples between the primary and secondary electrodes, as well as the corresponding battery casing voltage sample, can be collected at 2:00, 8:00, 14:00, and 20:00, respectively.

[0074] In this way, by acquiring multiple insulation impedance samples between the electrodes and the third electrode collected at different times, as well as the battery casing voltage sample corresponding to each insulation impedance sample, not only can the sample size be enriched, but the accuracy of analyzing the risk state of the battery pack through the fitted correlation can also be improved.

[0075] Step 2032: Determine the average insulation resistance and the average battery casing voltage corresponding to the average insulation resistance.

[0076] The average insulation impedance samples of the same battery at different times and the battery casing voltage samples corresponding to each insulation impedance sample are averaged to obtain the average insulation impedance of the battery and the average battery casing voltage corresponding to the average insulation impedance.

[0077] Step 2033: Fit the average insulation resistance and the average battery casing voltage to obtain the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage.

[0078] In this embodiment, the average insulation resistance and the average battery casing voltage are linearly fitted to obtain a fitting curve, which is used to represent the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage.

[0079] The changing trend of the fitted curve obtained by the above method can better reflect the changing trend of the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage, thereby improving the accuracy of the fitted correlation and further improving the accuracy of analyzing the risk state of the battery pack through the fitted correlation.

[0080] In this embodiment of the application, after utilizing the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage obtained from the above steps, step S203 further determines the endpoint voltage value of the preset voltage range through the following steps:

[0081] Step 2034: Obtain the critical values ​​of insulation impedance when the battery is in different risk states; where risk states include no risk state, low risk state, critical risk state, and high risk state.

[0082] Here, a risk-free state refers to a state where the battery is safe and works normally without any abnormal risks; a low-risk state refers to a state where the battery has some risks, but these risks will not affect the normal operation and lifespan of the battery and can be temporarily ignored; a critical risk state refers to a state where the battery may have some risks that could affect its operation; and a high-risk state refers to a state where the battery has abnormalities that could affect its normal operation, thereby affecting its lifespan and safety.

[0083] The critical insulation resistance values ​​for batteries under different risk conditions can be obtained by combining the operator's historical work experience. For example, the critical insulation resistance value for batteries under no-risk conditions can be 20MΩ, the critical insulation resistance value for batteries under low-risk conditions can be 0.6MΩ, and the critical insulation resistance value for batteries under high-risk conditions can be 0.1MΩ.

[0084] Step 2035: Based on the relationship between the insulation resistance between the electrode and the third electrode and the battery casing voltage, determine the terminal voltage value corresponding to the critical value of the insulation resistance.

[0085] Here, based on the fitting curve corresponding to the relationship between the insulation impedance between the electrode and the third electrode and the battery casing voltage, the endpoint voltage value corresponding to the critical value of the insulation impedance of the battery under different risk conditions is determined from the fitting curve.

[0086] Specifically, the first, second, and third critical insulation impedance values ​​are obtained for the battery in three states: risk-free, low-risk, and high-risk. Based on the fitted curves corresponding to the correlation relationships, the first terminal voltage value corresponding to the first critical insulation impedance value, the second terminal voltage value corresponding to the second critical insulation impedance value, and the third terminal voltage value corresponding to the third critical insulation impedance value can be derived. Here, the first terminal voltage value is defined as M0, the second terminal voltage value as M1, and the third terminal voltage value as M2. The risk-free state represents a state where the battery casing voltage is less than or equal to the first terminal voltage value M0; the low-risk state represents a state where the battery casing voltage is greater than the first terminal voltage value M0 and less than or equal to the second terminal voltage value M1; the critical state represents a state where the battery casing voltage is greater than the second terminal voltage value M1 and less than or equal to the third terminal voltage value M2; and the high-risk state represents a state where the battery casing voltage is greater than the third terminal voltage value M2.

[0087] For example, such as Figure 3 As shown, Figure 3 This is a schematic diagram of the fitting curve corresponding to the relationship between the insulation resistance between the electrode and the third electrode and the battery casing voltage, provided in an embodiment of this application. The horizontal axis of the fitting curve represents the insulation resistance, and the vertical axis represents the battery casing voltage. Figure 3 It is known that the battery casing voltage is inversely proportional to the insulation resistance; that is, the greater the insulation resistance between the electrode and the third electrode, the smaller the battery casing voltage. For example, if the critical insulation resistance value for the battery in a risk-free state is 20MΩ, then according to the fitting curve corresponding to the correlation between insulation resistance and battery casing voltage, the voltage at the first endpoint is 1V. If the critical insulation resistance value for the battery in a low-risk state is 0.6MΩ, then according to the fitting curve corresponding to the correlation between insulation resistance and battery casing voltage, the voltage at the second endpoint is 2.25V. If the critical insulation resistance value for the battery in a high-risk state is 0.1MΩ, then according to the fitting curve corresponding to the correlation between insulation resistance and battery casing voltage, the voltage at the third endpoint is 3V. Here, a risk-free state means a battery casing voltage less than or equal to 1V; a low-risk state means a battery casing voltage greater than 1V and less than or equal to 2.25V; a risk-critical state means a battery casing voltage greater than 2.25V and less than or equal to 3V; and a high-risk state means a battery casing voltage greater than 3V.

[0088] S204. Determine the target risk state of the target battery pack based on the risk state corresponding to the target voltage range.

[0089] In step S204, a risk state corresponds to a preset voltage range. The target voltage range to which the first target voltage value belongs can be determined based on the magnitude of the first target voltage value. The preset voltage range is one of the target voltage ranges. In this way, the risk state corresponding to the target voltage range can be determined, and thus the target risk state of the target battery pack can be determined.

[0090] In this embodiment of the application, before finally determining the target risk state of the target battery pack, multiple tests can be conducted to determine whether the target battery pack is really in the target risk state, so as to ensure the accuracy of the results.

[0091] Here, step S204 specifically includes: if the risk state corresponding to the target voltage range to which the first target voltage value belongs is a critical risk state, then repeatedly detect whether the battery corresponding to the first target voltage value is the same battery; if so, then determine that the target battery pack is in a critical risk state.

[0092] For example, when initially determining that a target battery pack is in a critical risk state, the same string of batteries in the target battery pack in the critical risk state can be bubble sorted three times consecutively. If the first target voltage value appears in the same string of batteries three times consecutively, then the target battery pack can be determined to be in a critical risk state.

[0093] In the above method, since the target battery pack is very close to the high-risk state when it is in the critical risk state, there is a risk that the target battery pack may become high-risk at any time. Therefore, multiple tests are required to ensure that the target battery pack is in the critical risk state rather than the high-risk state, which helps to take appropriate intervention measures to provide early warning for the target battery pack.

[0094] After determining the target risk state of the target battery pack, different intervention measures need to be taken according to the type of target risk state to provide timely warnings and responses to potential risks to the battery. Simultaneously, the number of battery strings containing the first target voltage value is output. This number of battery strings is represented by flag bits, such as S1, S2, and S3, where S represents the number of battery strings.

[0095] Optionally, the insulation monitoring method provided in this application embodiment further includes:

[0096] Step 205: If the target battery pack is in a critical risk state, then control the increase of the number of detections of the target battery pack.

[0097] Here, by increasing the number of times the target battery pack is detected, the detection frequency of the target battery pack can be increased, thereby ensuring that high-risk trends that may exist in the target battery pack can be detected in a timely manner during frequent detection, so as to provide early warning.

[0098] Step 206: If the target battery pack is in a high-risk state, lock the target battery pack through the control loop to stop its use.

[0099] Here, if the target battery pack is detected to be in a high-risk state, the target battery pack is locked through a control loop to prevent the battery from being used further.

[0100] By employing the aforementioned intervention methods, when the target battery pack is in a critical risk state, the frequency of inspections can be increased so that staff can quickly identify potential risks. When the target battery pack is in a high-risk state, its use can be promptly stopped to prevent further damage to the battery from continued use.

[0101] Furthermore, the accuracy of the analysis can be improved by overlaying the battery's temperature information and state of charge during the test. Specifically, the method provided in this application embodiment further includes:

[0102] Step 207: Collect ambient temperature data and current flowing through the target battery pack.

[0103] Here, ambient temperature data refers to the temperature data of the surrounding environment near the target battery pack.

[0104] Step 208: Determine the state of charge of the target battery pack based on the determined first target voltage value and current.

[0105] Here, the state of charge (SOC) represents the ratio of a battery's remaining capacity after a period of use or long-term storage to its capacity when fully charged, usually expressed as a percentage. Its value ranges from 0 to 1; when SOC = 0, the battery is fully discharged; when SOC = 1, the battery is fully charged.

[0106] Specifically, based on the first target voltage value and the current, the remaining capacity of the battery after a period of use can be determined, and the capacity of the battery in a fully charged state obtained in advance can be determined, thereby determining the state of charge of the battery. In this way, the state of charge of the battery corresponding to the first target voltage value can be used to represent the state of charge of the target battery pack.

[0107] Step 209: Input the ambient temperature data and the determined state of charge into the pre-trained battery detection model, and output the risk state of the target battery pack to verify whether the risk state of the target battery pack is the same as the target risk state.

[0108] Here, the input to the battery detection model is ambient temperature data and state of charge, and the output of the battery detection model is the risk state of the battery pack. Therefore, the risk state of the target battery pack can be obtained through this battery detection model to verify whether the risk state of the target battery pack is the same as the target risk state.

[0109] The battery pack insulation monitoring method provided in this application provides a method for measuring the voltage between the electrode and the third electrode in real time during the battery assembly process by setting a third electrode on the battery casing to obtain real-time insulation information of the battery. By determining the relationship between the determined first target voltage value and the preset voltage range, the target voltage range to which the first target voltage value belongs is determined. Then, the target risk state of the target battery pack is determined according to the risk state corresponding to the target voltage range, so as to achieve the purpose of real-time detection of the risk state of the battery pack. The endpoint voltage value of the preset voltage range is determined according to the correlation between the insulation impedance between the electrode and the third electrode and the voltage of the battery casing to obtain a more accurate preset voltage range. This enables real-time detection of the risk state of the battery pack, which helps to provide timely warnings and rapid responses to the battery pack, thereby improving the life and safety of the battery pack.

[0110] Please see Figure 4 , Figure 4 A flowchart illustrating another battery pack insulation monitoring method provided in this application embodiment. Figure 4 As shown in the embodiments of this application, the insulation monitoring method includes:

[0111] S401. Collect the second voltage value between the electrode and the third electrode of each battery in the battery pack to obtain multiple second voltage values ​​corresponding to the battery pack.

[0112] Here, the second voltage value between the positive and third terminals of each battery in the battery pack is collected to obtain multiple second voltage values ​​corresponding to the battery pack.

[0113] Optionally, when an instruction is received to collect the second voltage value between the electrode and the third electrode of each battery in the target battery pack, the second voltage value between the electrode and the third electrode of each battery in the target battery pack is collected after a preset time delay.

[0114] S402. Determine the second target voltage value with the largest value from multiple second voltage values.

[0115] For example, a bubble sort method can be used to determine the second target voltage value with the largest value from multiple second voltage values.

[0116] S403. Determine the battery pack whose second target voltage value is not greater than the risk potential threshold as the target battery pack.

[0117] Among them, the risk potential threshold refers to the terminal voltage value corresponding to the critical value of insulation resistance when the battery is in a risk-free state, which is determined based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage.

[0118] Here, a risk-free state refers to a safe state where the battery is functioning normally and there is no abnormal risk. The critical insulation resistance value of the battery in a risk-free state is obtained. Based on the fitted curve corresponding to the correlation, the endpoint voltage value corresponding to the critical insulation resistance value (corresponding to the first endpoint voltage value mentioned above) can be derived. For example, the critical insulation resistance value of the battery in a risk-free state can be 20MΩ. According to the fitted curve corresponding to the correlation between insulation resistance and battery casing voltage, the endpoint voltage value is 1V. Therefore, the risk potential threshold is 1V.

[0119] In step S403, batteries with a second target voltage value greater than the risk potential threshold can be filtered out by the risk potential threshold, and the battery pack with a second target voltage value not greater than the risk potential threshold is selected as the target battery pack.

[0120] The above methods can be used to perform preliminary verification of the battery pack, to detect whether there are any abnormalities in the battery at the time of manufacture, so that the target battery pack for subsequent testing is free of any abnormalities at the time of manufacture.

[0121] S404. Collect the first voltage value between the electrode and the third electrode of each battery in the target battery pack to obtain multiple first voltage values ​​corresponding to the target battery pack.

[0122] S405. Determine the first target voltage value with the largest value from multiple first voltage values.

[0123] S406. Determine the target voltage range to which the first target voltage value belongs based on the preset voltage range between the electrode and the third electrode when the battery is in different risk states; wherein, the endpoint voltage value of the preset voltage range is determined based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage.

[0124] S407. Determine the target risk state of the target battery pack based on the risk state corresponding to the target voltage range.

[0125] The descriptions of S404 to S407 can be referred to the descriptions of S201 to S204, and can achieve the same technical effect, so they will not be elaborated further.

[0126] In steps S401 to S407 above, the voltage value between the positive electrode of the battery and the newly introduced third electrode (the third electrode is connected to the casing) is detected a second time. The voltage value is processed according to different pre-set evaluation strategies to determine the risk status of the target battery pack, facilitating corresponding early warning measures for battery packs in different risk states. The evaluation strategies include a first evaluation strategy and a second evaluation strategy. The first evaluation strategy identifies battery packs whose second target voltage value is not greater than a risk potential threshold as target battery packs. The second evaluation strategy determines the target voltage range to which the first target voltage value belongs based on a preset voltage range between the electrode and the third electrode when the battery is in different risk states, and determines the target risk state of the target battery pack based on the risk state corresponding to the target voltage range. The pre-set evaluation strategies need to be determined by combining the relationship between the insulation resistance between the positive and third electrodes of the battery and the voltage of the battery casing. These strategies can be set in the Building Management System (BMS).

[0127] The battery pack insulation monitoring method provided in this application is simple and easy to operate. It filters out battery packs that do not meet the first evaluation strategy through the first detection, and only evaluates the remaining battery packs according to the second evaluation strategy. At the same time, the setting of the first evaluation strategy and the second evaluation strategy are closely combined with the correlation between the battery insulation impedance and the battery casing voltage. This can improve the detection accuracy while saving detection costs, and thus enable real-time detection of the risk status of the battery pack. This helps to provide timely warnings for the battery pack, thereby improving the battery pack's lifespan and safety, and ensuring the safety of the battery pack in storage and various usage scenarios.

[0128] Based on the same inventive concept, this application also provides an insulation monitoring device for a battery pack corresponding to the insulation monitoring method for a battery pack. Since the principle of the device in this application is similar to the insulation monitoring method for a battery pack described above, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0129] The insulation monitoring device provided in this application includes: a data acquisition module and a data processing module; the data acquisition module includes multiple data acquisition units, each of which is connected to the electrode and the third electrode of one of the batteries in the target battery pack; the data acquisition module is also connected to the data processing module.

[0130] For example, such as Figure 5As shown, the insulation monitoring device 500 includes a data acquisition module 501 and a data processing module 502. The data acquisition module 501 includes multiple data acquisition units, each connected to the electrode and third electrode of one of the batteries in the target battery pack 600. The data acquisition module 501 is also connected to the data processing module 602. The target battery pack 600 consists of five batteries (S1, S2, S3, S4, and S5) connected in series, where S represents the number of batteries in series. When using the insulation monitoring device 500 for insulation monitoring, upon receiving an instruction to collect the voltage value (first voltage value or second voltage value) between the positive and third electrodes of each battery in the target battery pack, the voltage value is collected after a preset time delay. The preset time is preferably 5 to 10 seconds. The acquisition frequency of the data acquisition module 501 is preferably set to 4 hours to 6 hours, which not only reduces the amount of data processing but also provides effective early warning.

[0131] The data acquisition module 501 is used to acquire the first voltage value between the electrode and the third electrode of each battery in the target battery pack, and obtain multiple first voltage values ​​corresponding to the target battery pack.

[0132] The data processing module 502 is used to determine the first target voltage value with the largest value from multiple first voltage values; to determine the target voltage range to which the first target voltage value belongs based on the preset voltage range between the electrode and the third electrode when the battery is in different risk states; wherein, the endpoint voltage value of the preset voltage range is determined based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage; and to determine the target risk state of the target battery pack based on the risk state corresponding to the target voltage range.

[0133] In one optional embodiment of this application, the data processing module 502 is used to fit the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage through the following steps:

[0134] Multiple insulation impedance samples between the electrode and the third electrode are collected at different times, as well as the battery casing voltage sample corresponding to each insulation impedance sample; the average insulation impedance and the average battery casing voltage corresponding to the average insulation impedance are determined; the average insulation impedance and the average battery casing voltage are fitted to obtain the correlation between the insulation impedance between the electrode and the third electrode and the battery casing voltage.

[0135] In one optional embodiment of this application, the data processing module 502 is used to determine the endpoint voltage value of a preset voltage range through the following steps:

[0136] Obtain the critical insulation impedance values ​​of the battery under different risk states; where risk states include no risk state, low risk state, critical risk state, and high risk state; determine the terminal voltage value corresponding to the critical insulation impedance value based on the correlation between the insulation impedance between the electrode and the third electrode and the battery casing voltage.

[0137] In one optional embodiment of this application, the data acquisition module 501 is further configured to acquire the second voltage value between the electrode and the third electrode of each battery in the battery pack, thereby obtaining multiple second voltage values ​​corresponding to the battery pack.

[0138] The data processing module 502 is also used to determine the second target voltage value with the largest value from multiple second voltage values; and to determine the battery pack whose second target voltage value is not greater than the risk potential threshold as the target battery pack.

[0139] In one optional embodiment of this application, the risk potential threshold refers to the terminal voltage value corresponding to the critical value of insulation resistance when the battery is in a risk-free state, which is determined based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage.

[0140] In one optional embodiment of this application, the data processing module 502 is further configured to: if the target battery pack is in a critical risk state, control the increase of the number of detections of the target battery pack; if the target battery pack is in a high risk state, lock the target battery pack through a control loop to stop the use of the target battery pack.

[0141] In an optional embodiment of this application, the data processing module 502 is further configured to: if the risk state corresponding to the target voltage range to which the first target voltage value belongs is a risk critical state, then continuously detect whether the battery corresponding to the first target voltage value is the same battery; if so, then determine that the target battery pack is in a risk critical state.

[0142] In an optional embodiment of this application, the data acquisition module 501 is further configured to delay for a preset time when receiving an instruction to acquire the first voltage value between the electrode of each battery in the target battery pack and the third electrode.

[0143] In one optional embodiment of this application, the data acquisition module 501 is further used to acquire ambient temperature data of the target battery pack and current flowing through the battery pack;

[0144] The data processing module 502 is also used to determine the state of charge of the target battery pack based on the determined first target voltage value and current; input the ambient temperature data and the determined state of charge into the pre-trained battery detection model, and output the risk state of the target battery pack to verify whether the risk state of the target battery pack is the same as the target risk state.

[0145] The battery pack insulation monitoring device provided in this application embodiment is simple and easy to operate. It filters out battery packs that do not meet the first evaluation strategy through the first detection, and only evaluates the remaining battery packs according to the second evaluation strategy. At the same time, the setting of the first evaluation strategy and the second evaluation strategy are closely combined with the correlation between the battery insulation impedance and the battery casing voltage. This can improve the detection accuracy while saving detection costs, and thus detect the risk status of the battery pack in real time. This helps to provide timely warnings for the battery pack, thereby improving the battery pack's lifespan and safety, and ensuring the safety of the battery pack in storage and various usage scenarios.

[0146] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0147] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0148] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0149] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0150] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0151] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for monitoring the insulation of a battery pack, characterized in that, The method is applied to a battery pack comprising multiple batteries, each battery including two electrodes, the voltage between the two electrodes being the battery voltage, and each battery casing also having a third electrode, which is electrically connected to the casing; the insulation monitoring method includes: Collect the first voltage value between the electrode of each battery in the target battery pack and the third electrode to obtain multiple first voltage values ​​corresponding to the target battery pack; The first target voltage value with the largest value is determined from the plurality of first voltage values; Based on a preset voltage range between the electrode and the third electrode when the battery is under different risk conditions, a target voltage range to which the first target voltage value belongs is determined; wherein, the endpoint voltage values ​​of the preset voltage range are determined based on the correlation between the insulation impedance between the electrode and the third electrode and the battery casing voltage; wherein, the correlation between the insulation impedance between the electrode and the third electrode and the battery casing voltage is fitted through the following steps: acquiring multiple insulation impedance samples between the electrode and the third electrode collected at different times, and the battery casing voltage sample corresponding to each insulation impedance sample; determining the average insulation impedance and the average battery casing voltage corresponding to the average insulation impedance; fitting the average insulation impedance and the average battery casing voltage to obtain the correlation between the insulation impedance between the electrode and the third electrode and the battery casing voltage; The target risk state of the target battery pack is determined based on the risk state corresponding to the target voltage range.

2. The insulation monitoring method according to claim 1, characterized in that, The endpoint voltage values ​​of the preset voltage range are determined by the following steps: Obtain the critical values ​​of insulation impedance of the battery under different risk states; wherein, the risk states include no risk state, low risk state, critical risk state, and high risk state; Based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage, the endpoint voltage value corresponding to the critical value of the insulation resistance is determined.

3. The insulation monitoring method according to claim 1, characterized in that, The method further includes: The second voltage value between the electrode and the third electrode of each battery in the battery pack is collected to obtain multiple second voltage values ​​corresponding to the battery pack. The second target voltage value with the largest value is determined from the plurality of second voltage values; The battery pack whose second target voltage value is not greater than the risk potential threshold is identified as the target battery pack, so that the target battery pack for subsequent testing is free of factory defects.

4. The insulation monitoring method according to claim 3, characterized in that, The risk potential threshold refers to the terminal voltage value corresponding to the critical value of insulation resistance when the battery is in a risk-free state, determined based on the correlation between the insulation resistance between the electrode and the third electrode and the battery casing voltage.

5. The insulation monitoring method according to claim 1, characterized in that, The method further includes: If the target battery pack is in a critical risk state, the number of times the target battery pack is detected is increased. If the target battery pack is in a high-risk state, the target battery pack is locked through a control loop to stop its use.

6. The insulation monitoring method according to claim 1, characterized in that, The step of determining the target risk state of the target battery pack based on the risk state corresponding to the target voltage range includes: If the risk state corresponding to the target voltage range to which the first target voltage value belongs is a critical risk state, then the battery corresponding to the first target voltage value is detected multiple times in succession to see if it is the same battery. If so, the target battery pack is determined to be in a critical risk state.

7. The insulation monitoring method according to claim 1, characterized in that, The step of acquiring the first voltage value between the electrode of each cell in the target battery pack and the third electrode includes: When an instruction is received to collect the first voltage value between the electrode of each battery in the target battery pack and the third electrode, the first voltage value between the electrode of each battery in the target battery pack and the third electrode is collected after a preset time delay.

8. The insulation monitoring method according to claim 1, characterized in that, The method further includes: Collect ambient temperature data and current flowing through the target battery pack; The state of charge of the target battery pack is determined based on the determined first target voltage value and the current. The ambient temperature data and the determined state of charge are input into a pre-trained battery detection model, which outputs the risk state of the target battery pack to verify whether the risk state of the target battery pack is the same as the target risk state.

9. An insulation monitoring device for a battery pack, characterized in that, The insulation monitoring device includes: a data acquisition module and a data processing module; the data acquisition module includes multiple data acquisition units, each of which is connected to the electrode and the third electrode of one of the batteries in the target battery pack; the data acquisition module is also connected to the data processing module. The data acquisition module is used to acquire the first voltage value between the electrode of each battery in the target battery pack and the third electrode, and obtain multiple first voltage values ​​corresponding to the target battery pack. The data processing module is used to determine the largest first target voltage value from the plurality of first voltage values; and to determine the target voltage range to which the first target voltage value belongs based on a preset voltage range between the electrode and the third electrode when the battery is in different risk states. The endpoint voltage values ​​of the preset voltage range are determined based on a correlation between the insulation impedance between the electrode and the third electrode and the battery casing voltage. The correlation between the insulation impedance between the electrode and the third electrode and the battery casing voltage is fitted through the following steps: acquiring multiple insulation impedance samples between the electrode and the third electrode collected at different times, and a battery casing voltage sample corresponding to each insulation impedance sample; determining the average insulation impedance and the average battery casing voltage corresponding to the average insulation impedance; fitting the average insulation impedance and the average battery casing voltage to obtain the correlation between the insulation impedance between the electrode and the third electrode and the battery casing voltage; and determining the target risk state of the target battery pack based on the risk state corresponding to the target voltage range.

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