Faulty battery detection methods, electronic devices and storage media

Abstract

This invention provides a faulty battery detection method, electronic device, and storage medium, which can be applied to the field of fault detection technology for energy storage systems. The method includes: in response to M battery cells in a battery cluster not being in an equalized state, acquiring the voltage change values ​​of each of the M battery cells within a target time period, where the target time period is determined based on a single voltage sampling period; in response to the voltage change values ​​of each of the N cascaded battery cells in the battery cluster being less than zero, and the voltage change values ​​of each of the M-N battery cells in the battery cluster being greater than zero, obtaining a first statistical voltage change value based on the voltage change values ​​of each of the N battery cells, and obtaining a second statistical voltage change value based on the voltage change values ​​of each of the M-N battery cells, where N < M; and obtaining a detection result indicating whether the battery cluster is in a faulty or normal state based on the difference between the second statistical voltage change value and the first statistical voltage change value and a predetermined voltage change threshold.

Description

Technical Field

[0001] This invention relates to the field of fault detection technology for energy storage systems, and more specifically, to a faulty battery detection method, electronic device, and storage medium. Background Technology

[0002] Lithium-ion battery electrochemical energy storage systems, with their advantages of rapid response, high energy density and long cycle life, have gradually become an important support for suppressing new energy fluctuations and improving grid flexibility.

[0003] Among related technologies, the fault detection strategies used in lithium battery energy storage systems have relatively low accuracy. Summary of the Invention

[0004] In view of this, the present invention provides a faulty battery detection method, an electronic device, and a storage medium.

[0005] One aspect of the present invention provides a faulty battery detection method, comprising: in response to M battery cells in a battery cluster not being in an equalized state, acquiring the voltage change values ​​of each of the M battery cells within a target time period, wherein the target time period is determined based on a single voltage sampling period, the equalized state represents voltage regulation of the battery cluster using a predetermined voltage regulation strategy, and M is a positive integer; in response to N cascaded battery cells in the battery cluster having voltage change values ​​that are all less than zero, and MN battery cells in the battery cluster having voltage change values ​​that are all greater than zero, obtaining a first statistical voltage change value based on the voltage change values ​​of each of the N battery cells, and obtaining a second statistical voltage change value based on the voltage change values ​​of each of the MN battery cells, wherein N < M and N is a positive integer; and obtaining a detection result indicating whether the battery cluster is in a faulty state or a normal state based on the difference between the second statistical voltage change value and the first statistical voltage change value and a predetermined voltage change threshold.

[0006] According to an embodiment of the present invention, the start time of the target time period is the time corresponding to the sum of the current sampling time and the preset delay, and the end time of the target time period is the previous sampling time of the current sampling time; or the start time of the target time period is the current sampling time, and the end time of the target time period is the previous sampling time of the current sampling time; wherein, obtaining the voltage change value of each of the M battery cells within the target time period includes: for any one of the M battery cells, obtaining the first voltage value of the battery cell at the start time and the second voltage value at the end time; and obtaining the voltage change value of the battery cell based on the first voltage value and the second voltage value.

[0007] According to an embodiment of the present invention, the preset delay is greater than a single voltage sampling period.

[0008] According to an embodiment of the present invention, the first statistical voltage change value is the average of the voltage change values ​​of each of the N cascaded battery cells, and the second statistical voltage change value is the average of the voltage change values ​​of each of the MN battery cells; wherein, based on the difference between the second statistical voltage change value and the first statistical voltage change value and a predetermined voltage change threshold, a detection result for indicating whether the battery cluster is in a fault state or a normal state is obtained, including: when the absolute value of the difference is greater than or equal to the predetermined voltage change threshold, a detection result for indicating that the battery cluster is in a fault state is obtained; when the absolute value of the difference is less than the predetermined voltage change threshold, a detection result for indicating that the battery cluster is in a normal state is obtained.

[0009] According to an embodiment of the present invention, the method further includes: in response to obtaining a detection result indicating that the battery cluster is in a fault state, determining that the N cascaded battery cells are short-circuit faulty batteries.

[0010] According to an embodiment of the present invention, the predetermined voltage change threshold is determined by the following operation: using the loop current equation, the voltage drop value of the m-th battery cell in the battery cluster and the average voltage rise value of the M-1 battery cells in the battery cluster excluding the m-th battery cell are obtained, wherein the m-th battery cell is regarded as a short-circuit fault battery, the loop current equation is constructed based on the topology parameters of the energy storage system in which the battery cluster is located, m is a positive integer and 1 < m < M; the predetermined voltage change threshold is determined based on the absolute value of the difference between the average voltage rise value of the M-1 battery cells and the voltage drop value of the m-th battery cell.

[0011] According to an embodiment of the present invention, the voltage drop of the m-th battery cell in the battery cluster and the average voltage rise of the M-1 battery cells excluding the m-th battery cell are obtained using the loop current equation, including: obtaining the first branch current value of the branch containing the m-th battery cell and the second branch current value of the branch containing the M-1 battery cells using the loop current equation; obtaining the internal resistance value of the m-th battery cell based on the terminal voltage change value and terminal current change value of the m-th battery cell when switching from a constant current charging / discharging state to a stationary state; obtaining the open-circuit voltage value of the m-th battery cell based on the internal resistance value of the m-th battery cell and the terminal voltage value and terminal current value of the m-th battery cell in the constant current charging / discharging state; and obtaining the voltage drop of the m-th battery cell and the average voltage rise of the M-1 battery cells based on the open-circuit voltage value and internal resistance value of the m-th battery cell.

[0012] According to an embodiment of the present invention, determining a predetermined voltage change threshold based on the absolute value of the difference between the average voltage rise of M-1 battery cells and the voltage drop of the m-th battery cell includes: obtaining an initial voltage change threshold based on the absolute value of the difference between the average voltage rise of M-1 battery cells and the voltage drop of the m-th battery cell; determining a braking coefficient based on at least one of the state of charge information, health status information, and operating condition information of each of the M battery cells; and determining the predetermined voltage change threshold based on the initial voltage change threshold and the braking coefficient.

[0013] Another aspect of the present invention provides an electronic device comprising: one or more processors; and a memory for storing one or more programs, wherein, when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to perform the method as described above.

[0014] Another aspect of the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed, are used to implement the method described above.

[0015] Another aspect of the present invention provides a computer program product comprising computer-executable instructions which, when executed, are used to implement the method described above.

[0016] According to an embodiment of the present invention, the equilibrium state of the energy storage system refers to the voltage regulation of M individual cells in the battery cluster using a predetermined voltage regulation strategy to reduce the difference in voltage or capacity between the individual cells. Therefore, even when the battery cluster is in an equilibrium state, there may be a phenomenon where the voltage of some individual cells decreases and the voltage of others increases due to regulation. Thus, if fault detection is performed when the battery cluster is in an equilibrium state, it will lead to misjudgment of the fault state. Therefore, performing fault detection on the battery cluster when it is not in an equilibrium state with voltage regulation using the predetermined voltage regulation strategy reduces the possibility of misjudgment and improves the accuracy of fault detection. If, during the target time period, at least one cascaded individual cell in the battery cluster has a voltage change value less than zero and the voltage change values ​​of the remaining individual cells are all greater than zero, it indicates that the voltage change direction of some individual cells in the battery cluster is opposite to that of others. Since the voltage change direction of some individual cells may also be opposite to that of others in the event of a fault, subsequent judgment is performed under the above conditions, further improving the accuracy of fault detection. Under the condition of meeting the above, the first statistical voltage change value and the second statistical voltage change value are determined, and the detection result is obtained based on the difference between the second statistical voltage change value and the first statistical voltage change value and a predetermined threshold, so as to determine whether the battery cluster is in a fault state or a normal state. Thus, the voltage change of multiple battery cells in the battery cluster within the target time period is considered in a coordinated manner to detect faults, reduce false faults or false faults, and improve the accuracy of fault detection. Attached Figure Description

[0017] The above and other objects, features and advantages of the present invention will become more apparent from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

[0018] Figure 1 A flowchart of a faulty battery detection method according to an embodiment of the present invention is shown;

[0019] Figure 2 A circuit diagram illustrating a partial short-circuit fault in a battery cluster according to an embodiment of the present invention is shown;

[0020] Figure 3 It shows Figure 2 The circuit diagram shown illustrates the voltage changes of different battery cells.

[0021] Figure 4 It shows Figure 2 The equivalent circuit diagram of the circuit shown in the figure;

[0022] Figure 5A schematic diagram of an equivalent model of a battery cell according to an embodiment of the present invention is shown; and

[0023] Figure 6 A block diagram of an electronic device suitable for implementing a faulty battery detection method according to an embodiment of the present invention is shown. Detailed Implementation

[0024] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the invention for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention.

[0025] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0026] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein are to be interpreted in a manner consistent with the context of this specification, and not in an idealized or overly rigid way.

[0027] When using expressions such as "at least one of A, B and C", they should generally be interpreted in accordance with the meaning that is commonly understood by those skilled in the art (e.g., "a system having at least one of A, B and C" should include, but is not limited to, a system having A alone, a system having B alone, a system having C alone, a system having A and B, a system having A and C, a system having B and C, and / or a system having A, B and C, etc.).

[0028] Currently, renewable energy is in the process of being integrated into the power system on a large scale. However, the strong randomness and weak disturbance resistance of new energy power generation can easily lead to problems such as voltage instability and frequency fluctuations in the power system. Lithium batteries can serve as the energy carrier for electrochemical energy storage systems. Against this backdrop, the further development of energy storage systems is constrained by the technical bottlenecks in protection strategies.

[0029] Currently, the short-circuit protection device on the DC side of energy storage power stations uses fuses. However, fuses provide protection within a predetermined fault current range, which is difficult to cope with fault current changes under complex operating conditions. At the same time, after the fuse is activated, the Battery Management System (BMS) has difficulty accurately locating the fault, resulting in delayed fault isolation or even cascading failure, thus causing further spread of the fault.

[0030] In view of this, embodiments of the present invention provide a faulty battery detection method, comprising: in response to M battery cells in a battery cluster not being in an equalized state, acquiring the voltage change values ​​of each of the M battery cells within a target time period, wherein the target time period is determined based on a single voltage sampling period, the equalized state represents voltage regulation of the battery cluster using a predetermined voltage regulation strategy, and M is a positive integer; in response to the voltage change values ​​of each of the N cascaded battery cells in the battery cluster being less than zero, and the voltage change values ​​of each of the MN battery cells in the battery cluster being greater than zero, obtaining a first statistical voltage change value based on the voltage change values ​​of each of the N battery cells and obtaining a second statistical voltage change value based on the voltage change values ​​of each of the MN battery cells, wherein N < M and N is a positive integer; and obtaining a detection result indicating whether the battery cluster is in a faulty state or a normal state based on a predetermined voltage change threshold and the difference between the first statistical voltage change value and the second statistical voltage change value.

[0031] Figure 1 A flowchart of a faulty battery detection method according to an embodiment of the present invention is shown.

[0032] like Figure 1 As shown, the method 100 includes operations S110 to S130.

[0033] In operation S110, in response to the fact that M battery cells in the battery cluster are not in an equal state, the voltage change values ​​of each of the M battery cells are obtained within the target time period. Here, M is a positive integer.

[0034] In operation S120, in response to the fact that the voltage change values ​​of each of the N cascaded battery cells in the battery cluster are all less than zero, and the voltage change values ​​of each of the MN battery cells in the battery cluster are all greater than zero, a first statistical voltage change value is obtained based on the voltage change values ​​of each of the N battery cells, and a second statistical voltage change value is obtained based on the voltage change values ​​of each of the MN battery cells.

[0035] In operation S130, a detection result is obtained based on the difference between the second statistical voltage change value and the first statistical voltage change value and a predetermined voltage change threshold, which indicates whether the battery cluster is in a fault state or a normal state.

[0036] According to an embodiment of the present invention, the energy storage system includes multiple parallel battery clusters. Each battery cluster includes M cascaded battery cells. An equilibrium state refers to the voltage regulation of the M battery cells in the battery cluster using a predetermined voltage regulation strategy (e.g., an active regulation strategy or a passive regulation strategy) to reduce the difference in voltage or capacity between the individual battery cells in the cluster. That is, even when the battery cluster is in an equilibrium state, there may be a phenomenon where the voltage of some battery cells decreases while the voltage of others increases, leading to misjudgments of fault conditions.

[0037] Therefore, when the battery cluster is in a balanced state, the detection process for the faulty battery is not triggered until the battery cluster reaches a balanced state. That is, when M battery cells in the battery cluster are not in a balanced state, the voltage change values ​​of each of the M battery cells within the target time period are obtained. The target time period is determined based on a single sampling period.

[0038] According to an embodiment of the present invention, when there are no locally short-circuited battery cells in the battery cluster, the voltage change trends of all battery cells within the same battery cluster are the same, either all increasing or all decreasing. To analyze the voltage changes of each battery cell in the battery cluster when locally short-circuited battery cells exist, the following will be conducted... Figure 2 and Figure 3 Please provide an explanation.

[0039] Figure 2 A circuit diagram illustrating a partial short-circuit fault in a battery cluster according to an embodiment of the present invention is shown.

[0040] like Figure 2 As shown, the energy storage system includes multiple battery clusters connected in parallel, with an equivalent load resistance R. L Multiple battery clusters are connected in parallel. Battery cluster 210 includes multiple cascaded battery cells (e.g., battery cell 211 shown in the figure). A short-circuit resistor R is connected across the battery pack 220. s Battery pack 220 comprises multiple cascaded battery cells, meaning that a partial short circuit fault has occurred in battery pack 220 within the current energy storage system.

[0041] Figure 3 It shows Figure 2 The circuit diagram shown illustrates the voltage changes of different battery cells.

[0042] like Figure 3As shown, the horizontal axis represents the number of battery cells in battery pack 220. The vertical axis represents the difference between the voltage before and after the short circuit. The direction of voltage change in battery pack 220 before and after the short circuit is opposite to the direction of voltage change of the other battery cells in the same battery cluster. Therefore, the direction of voltage change of the battery cell that experiences a short circuit is opposite to that of the other battery cells in the same battery cluster before and after the short circuit.

[0043] Therefore, if there are N cascaded battery cells in the battery cluster, each with a voltage change value less than zero, and MN battery cells in the battery cluster, each with a voltage change value greater than zero, then the N cascaded battery cells can be identified as the battery pack to be determined. Based on the voltage change values ​​of the N battery cells, a first statistical voltage change value is obtained, and based on the voltage change values ​​of the MN battery cells, a second statistical voltage change value is obtained, where N < M and N is a positive integer.

[0044] According to an embodiment of the present invention, the first statistical voltage change value can represent the arithmetic mean or weighted average of the voltage change values ​​of each of the N individual battery cells, and correspondingly, the second statistical voltage change value can represent the arithmetic mean or weighted average of the voltage change values ​​of each of the MN individual battery cells. The difference between the second statistical voltage change value and the first statistical voltage change value is compared with a predetermined voltage change threshold to obtain a detection result used to indicate whether the battery cluster is in a faulty or normal state.

[0045] According to an embodiment of the present invention, the predetermined voltage change threshold represents the minimum value that the difference between the second statistical voltage change value and the first statistical voltage change value can reach when a partial short-circuit fault occurs in the current battery cluster, in conjunction with the above. Figure 3 It can be seen that the fewer the number of short-circuited battery cells, the smaller the difference between the second statistical voltage change value and the first statistical voltage change value.

[0046] According to an embodiment of the present invention, the equilibrium state of the energy storage system refers to the voltage regulation of M individual cells in the battery cluster using a predetermined voltage regulation strategy to reduce the difference in voltage or capacity between the individual cells. Therefore, even when the battery cluster is in an equilibrium state, there may be a phenomenon where the voltage of some individual cells decreases and the voltage of others increases due to regulation. Thus, if fault detection is performed when the battery cluster is in an equilibrium state, it will lead to misjudgment of the fault state. Therefore, performing fault detection on the battery cluster when it is not in an equilibrium state with voltage regulation using the predetermined voltage regulation strategy reduces the possibility of misjudgment and improves the accuracy of fault detection. If, during the target time period, at least one cascaded individual cell in the battery cluster has a voltage change value less than zero and the voltage change values ​​of the remaining individual cells are all greater than zero, it indicates that the voltage change direction of some individual cells in the battery cluster is opposite to that of others. Since the voltage change direction of some individual cells may also be opposite to that of others in the event of a fault, subsequent judgment is performed under the above conditions, further improving the accuracy of fault detection. Under the condition of meeting the above, the first statistical voltage change value and the second statistical voltage change value are determined, and the detection result is obtained based on the difference between the second statistical voltage change value and the first statistical voltage change value and a predetermined threshold, so as to determine whether the battery cluster is in a fault state or a normal state. Thus, the voltage change of multiple battery cells in the battery cluster within the target time period is considered in a coordinated manner to detect faults, reduce false faults or false faults, and improve the accuracy of fault detection.

[0047] According to an embodiment of the present invention, the start time of the target time period is the time corresponding to the sum of the current sampling time and the preset delay, and the end time of the target time period is the previous sampling time of the current sampling time; or the start time of the target time period is the current sampling time, and the end time of the target time period is the previous sampling time of the current sampling time; wherein, obtaining the voltage change value of each of the M battery cells within the target time period includes: for any one of the M battery cells, obtaining the first voltage value of the battery cell at the start time and the second voltage value at the end time; and obtaining the voltage change value of the battery cell based on the first voltage value and the second voltage value.

[0048] The start time of the target time period is taken as the time corresponding to the sum of the current sampling time and the preset delay, and the end time of the target time period is taken as the previous sampling time of the current sampling time. The voltage change value of the m-th battery cell in the battery cluster. It can be expressed as the following formula (1).

[0049] (1).

[0050] Where t represents the current sampling time, and τ represents the preset delay. Indicates a single sampling period. This represents the first voltage value of the m-th battery cell, given that the starting time corresponds to the sum of the current sampling time and the preset delay. The second voltage value represents the voltage of the m-th battery cell.

[0051] According to an embodiment of the present invention, for real-time voltage measurement of the BMS, there may be instances where the voltage of a single battery cell has changed but the BMS has not detected it in time, resulting in a lag in voltage measurement. Therefore, a preset delay can be used to compensate for the voltage measurement error caused by this lag. The preset delay can be greater than a single voltage sampling period, i.e., τ > 1. .

[0052] Taking the start time of the target time period as the current sampling time and the end time of the target time period as the previous sampling time, let's take the voltage change value of the m-th cell in the battery cluster as an example. It can also be expressed as the following formula (2).

[0053] (2).

[0054] in, This represents the first voltage value of the m-th battery cell, given that the starting time is the current sampling time.

[0055] According to an embodiment of the present invention, a preset delay is introduced based on two adjacent sampling times. The start time of the target time period is the time corresponding to the sum of the current sampling time and the preset delay, and the end time of the target time period is the previous sampling time of the current sampling time. Thus, for any battery cell in the battery cluster, the first voltage value of the battery cell at the start time and the second voltage value at the end time are obtained. Based on the first voltage value and the second voltage value, the voltage change value of the battery cell is obtained. Fault detection is performed based on the voltage change values ​​of each of the M battery cells in the battery cluster, achieving a fault response speed of milliseconds. Even for fault states with small voltage drops, accurate identification is possible, thereby reducing false positives and false negatives of fault states.

[0056] According to an embodiment of the present invention, a detection result for indicating whether a battery cluster is in a fault state or a normal state is obtained based on the difference between a second statistical voltage change value and a first statistical voltage change value and a predetermined voltage change threshold, including: obtaining a detection result for indicating that the battery cluster is in a fault state when the absolute value of the difference is greater than or equal to the predetermined voltage change threshold; and obtaining a detection result for indicating that the battery cluster is in a normal state when the absolute value of the difference is less than the predetermined voltage change threshold.

[0057] According to an embodiment of the present invention, in a battery cluster, the voltage change values ​​of each of the N cascaded battery cells are less than zero, i.e. ,in, This represents the voltage change of the n1-th battery cell in an N cascaded battery cluster, where the voltage changes of the remaining MN battery cells in the cluster are all greater than zero. ,in, Let n represent the voltage change value of the n2th battery cell out of MN battery cells. Calculate the first statistical voltage change value and the second statistical voltage change value.

[0058] According to an embodiment of the present invention, the first statistical voltage change value The average value of the voltage change of each of the N cascaded battery cells can be expressed as the following formula (3).

[0059] (3).

[0060] According to an embodiment of the present invention, the second statistical voltage change value The average value of the voltage change of each of the MN battery cells can be expressed as the following formula (4).

[0061] (4).

[0062] According to an embodiment of the present invention, the absolute value of the difference between the second statistical voltage change value and the first statistical voltage change value is greater than or equal to a predetermined voltage change threshold. In the case that, This yields a detection result indicating that the battery cluster is in a fault state. Conversely, the absolute value of the difference between the second statistical voltage change value and the first statistical voltage change value is less than a predetermined voltage change threshold. In the case that, < The detection results are obtained to indicate that the battery cluster is in a normal state.

[0063] According to an embodiment of the present invention, in response to obtaining a detection result indicating that the battery cluster is in a fault state, N cascaded battery cells are determined to be short-circuit faulty batteries.

[0064] According to an embodiment of the present invention, the absolute value of the difference between the second statistical voltage change value and the first statistical voltage change value is greater than or equal to a predetermined voltage change threshold. In this case, N battery cells with voltage changes less than zero are identified as short-circuit faulty batteries, thus achieving fault location.

[0065] According to an embodiment of the present invention, after obtaining the detection result indicating that the battery cluster is in a fault state, the N cascaded battery cells are identified as short-circuit faulty batteries, and the detection result is uploaded to trigger the protection mechanism to cut off the branch where the short-circuit faulty battery is located. The voltage change pattern of multiple battery cells in the same battery cluster is considered in a coordinated manner, thereby realizing the accurate detection and location of short-circuit faulty batteries.

[0066] According to an embodiment of the present invention, the predetermined voltage change threshold is determined by the following operation: using the loop current equation, the voltage drop value of the m-th battery cell in the battery cluster and the average voltage rise value of the M-1 battery cells excluding the m-th battery cell are obtained; the predetermined voltage change threshold is determined based on the absolute value of the difference between the average voltage rise value of the M-1 battery cells and the voltage drop value of the m-th battery cell. Wherein, m is a positive integer and 1 < m < M.

[0067] In combination with the above Figure 3 It is known that when the number of short-circuit faulty batteries is minimized, the difference between the voltage change of the battery cells without short-circuit faults and the voltage change of the battery cells with short-circuit faults is minimized. Therefore, any battery cell can be selected as the short-circuit faulty battery, and the predetermined voltage change threshold can be determined based on the absolute value of the difference between the average voltage rise of other battery cells in the same battery cluster and the current voltage drop. The voltage drop of the m-th battery cell represents the voltage change of the m-th battery cell before and after the short-circuit fault, and the average voltage rise of the M-1 battery cells represents the average value of the voltage changes of the M-1 battery cells before and after the fault.

[0068] The following will be based on Figure 2 Using the circuit diagram shown as an example, the loop current equations will be explained in the manual.

[0069] Figure 4 It shows Figure 2 The equivalent circuit diagram of the circuit shown.

[0070] like Figure 4 As shown, due to Figure 4 and Figure 2 Correspondingly, equivalent branches This represents the equivalent branch of multiple battery clusters in an energy storage system, excluding the cluster containing the battery with the short-circuit fault. Where, U F1 Indicates equivalent branch The equivalent voltage source for all corresponding battery cells, R F1 Indicates equivalent branch The equivalent resistance of all corresponding battery cells. Equivalent branch. This represents the equivalent branch where battery pack 220 is located, where U F3 Indicates equivalent branch The equivalent voltage source for all corresponding battery cells, R F3 Indicates equivalent branch The equivalent resistance of all corresponding battery cells. Equivalent branch. Indicates equivalent branch Equivalent branch in the battery cluster The equivalent branches corresponding to all battery cells on the left, U F2 Indicates equivalent branch The equivalent voltage source for all corresponding battery cells, R F2 Indicates equivalent branch The equivalent resistance of all corresponding battery cells. Equivalent branch. Indicates equivalent branch Equivalent branch in the battery cluster The equivalent branches corresponding to all battery cells on the right, U F4 Indicates equivalent branch The equivalent voltage source for all corresponding battery cells, R F4 Indicates equivalent branch The equivalent resistance of all corresponding battery cells. I1, I2, and I3 represent the current in the circuit indicated by the arrows.

[0071] According to an embodiment of the present invention, the loop current equation is constructed based on the topology parameters of the energy storage system in which the battery cluster is located, and can be expressed as the following formula (5).

[0072] (5).

[0073] Among them, B b Let T denote the loop matrix, and Z denote the matrix transpose symbol. b Represents the impedance matrix, U bs Represents the voltage source matrix, I b Denotes the current matrix, and B b Z b I b U bs They respectively satisfy the following equations (6) to (9).

[0074] (6).

[0075] (7).

[0076] (8).

[0077] (9).

[0078] in, Indicates short-circuit resistance. This represents the equivalent load resistance.

[0079] According to an embodiment of the present invention, the energy storage system includes A battery clusters. Taking each battery cluster as an example, each battery cluster includes M battery cells, and the i-th battery cell in the battery cluster is the first battery cell in the battery cluster to experience a short circuit fault. The total number of battery cells experiencing short circuit faults is N. The internal resistance of each battery cell is R0, the open circuit voltage is U0, and the constant discharge current of each battery cell is I before the short circuit fault occurs.

[0080] Equivalent branch Equivalent voltage source and equivalent resistance It can be expressed as the following formula (10).

[0081] (10).

[0082] Equivalent branch Equivalent voltage source and equivalent resistance It can be expressed as the following formula (11).

[0083] (11).

[0084] Equivalent branch Equivalent voltage source and equivalent resistance It can be expressed as the following formula (12).

[0085] (12).

[0086] Equivalent branch Equivalent voltage source and equivalent resistance It can be expressed as the following formula (13).

[0087] (13).

[0088] Equivalent load resistance .

[0089] According to an embodiment of the present invention, by combining the above formulas (5) to (13), the equivalent branch can be obtained. current Equivalent branch current Equivalent branch current Equivalent branch current .

[0090] According to an embodiment of the present invention, based on a loop current equation adapted to the topology parameters of the energy storage system, the absolute value of the difference between the average voltage rise of the remaining cells in the battery cluster and the voltage drop of the short-circuited faulty cell when a single cell experiences a short-circuit fault is used as a predetermined voltage change threshold, thus achieving adaptive determination of the predetermined voltage change threshold. Based on this, the battery cluster is determined to be in a faulty or normal state according to the predetermined voltage change threshold, improving the accuracy of faulty cell detection.

[0091] According to an embodiment of the present invention, the voltage drop of the m-th battery cell in the battery cluster and the average voltage rise of the M-1 battery cells excluding the m-th battery cell are obtained using the loop current equation, including: obtaining the first branch current value of the branch containing the m-th battery cell and the second branch current value of the branch containing the M-1 battery cells using the loop current equation; obtaining the internal resistance value of the m-th battery cell based on the terminal voltage change value and terminal current change value of the m-th battery cell when switching from a constant current charging / discharging state to a stationary state; obtaining the open-circuit voltage value of the m-th battery cell based on the internal resistance value of the m-th battery cell and the terminal voltage value and terminal current value of the m-th battery cell in the constant current charging / discharging state; and obtaining the voltage drop of the m-th battery cell and the average voltage rise of the M-1 battery cells based on the open-circuit voltage value and internal resistance value of the m-th battery cell.

[0092] Taking N=1, we can use the method obtained above from the loop current equation. The branch containing the m-th battery cell (i.e., the equivalent branch) is obtained. The first branch current value, and using the above and This yields the branches containing M-1 individual battery cells (i.e., the equivalent branches). and equivalent branches The second branch current value.

[0093] According to an embodiment of the present invention, the voltage change value of any one of the M-1 battery cells before and after a short-circuit fault occurs. It can be expressed as the following formula (14).

[0094] (14).

[0095] By iterating through and calculating the voltage change values ​​of each of the M-1 individual battery cells, the average voltage rise of the M-1 individual battery cells can be obtained.

[0096] According to an embodiment of the present invention, the voltage change value, i.e., the voltage drop value, of the m-th battery cell before and after the occurrence of a short-circuit fault is... It can be expressed as the following formula (15).

[0097] (15).

[0098] Therefore, it can be seen that formulas (14) and (15) are related to the open-circuit voltage and internal resistance of the battery cell. Research has shown that the internal resistance and open-circuit voltage of the battery cell change with its state of charge (SOC) and state of health (SOH). To further improve the accuracy of the voltage change threshold, the following can be used... Figure 5 Construct an equivalent model of the m-th battery cell and calculate the internal resistance and open-circuit voltage of the battery cell in real time.

[0099] Figure 5 A schematic diagram of an equivalent model of a battery cell according to an embodiment of the present invention is shown.

[0100] like Figure 5 As shown, a single battery cell can be equivalent to a voltage source connected in series with an internal resistance. , This represents the terminal voltage of a single battery cell under constant current charge / discharge conditions. This represents the current flowing through a single battery cell, i.e., the terminal current of the battery cell under constant current charging / discharging conditions. When changes occur, internal resistance The voltage will also change, so the internal resistance can be calculated according to the following formula (16).

[0101] (16).

[0102] For energy storage systems that maintain a constant current charge / discharge state, there is no current change in a single battery cell. When a battery cell switches from a constant current charge / discharge state to a static state, there is a change in its terminal voltage. Terminal current change value .

[0103] According to an embodiment of the present invention, the above formula (16) can be substituted into the following formula (17) to obtain the open circuit voltage value.

[0104] (17).

[0105] Therefore, the current internal resistance and open-circuit voltage of a single battery cell can be calculated in real time according to formulas (16) and (17), and the average voltage rise of M-1 battery cells and the voltage drop of the m-th battery cell can be calculated respectively according to formulas (14) and (15).

[0106] According to embodiments of the present invention, the voltage change threshold is determined using the loop current equation, making the fault state determination method applicable to various energy storage systems, thus improving compatibility and universality. Simultaneously, considering the changes in the internal resistance and open-circuit voltage of a battery cell with SOC and SOH, the real-time internal resistance and open-circuit voltage of the current battery cell are obtained by utilizing the changes in terminal voltage and terminal current when the battery cell switches from a constant current charging / discharging state to a resting state. This allows for real-time adjustment of the voltage change threshold, taking into account the influence of changes in SOC and SOH of the battery cell with factors such as battery life on the internal resistance and open-circuit voltage of the battery cell, further improving the accuracy of fault battery detection.

[0107] According to embodiments of the present invention, in addition to determining the state of the battery cluster based on the adaptive predetermined voltage change threshold and the difference between the second statistical voltage change value and the first statistical voltage change value, a predetermined coefficient can be introduced to further improve the accuracy of the detection results.

[0108] According to an embodiment of the present invention, determining a predetermined voltage change threshold based on the absolute value of the difference between the average voltage rise of M-1 battery cells and the voltage drop of the m-th battery cell includes: obtaining an initial voltage change threshold based on the absolute value of the difference between the average voltage rise of M-1 battery cells and the voltage drop of the m-th battery cell; determining a braking coefficient based on at least one of the state of charge information, health status information, and operating condition information of each of the M battery cells; and determining the predetermined voltage change threshold based on the initial voltage change threshold and the braking coefficient.

[0109] According to an embodiment of the present invention, the braking coefficient can be determined by learning the historical data of multiple battery cells, summarizing the mapping relationship between the historical data and the braking coefficient, and then determining the current braking coefficient from the mapping relationship by the mapping lookup table method. The braking coefficient can be 0.85 to 0.95.

[0110] Historical data includes at least one of historical state of charge information, historical health status information, and historical operating condition information.

[0111] According to an embodiment of the present invention, a predetermined voltage change threshold is obtained by adjusting the initial voltage change threshold based on the braking coefficient. This takes into account the influence of the battery cell's state of charge information, health status information, and operating condition information on the relevant parameters of the battery cell, filling the gap in fault detection under extreme or complex operating conditions, and further improving the accuracy of fault detection in various application scenarios.

[0112] Figure 6 A block diagram of an electronic device suitable for implementing a faulty battery detection method according to an embodiment of the present invention is shown. Figure 6The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of use of the embodiments of the present invention.

[0113] like Figure 6 As shown, an electronic device 600 according to an embodiment of the present invention includes a processor 601, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 602 or a program loaded from a storage portion 608 into a random access memory (RAM) 603. The processor 601 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or an associated chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 601 may also include onboard memory for caching purposes. The processor 601 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present invention.

[0114] RAM 603 stores various programs and data required for the operation of electronic device 600. Processor 601, ROM 602, and RAM 603 are interconnected via bus 604. Processor 601 executes various operations of the method flow according to embodiments of the present invention by executing programs in ROM 602 and / or RAM 603. It should be noted that the programs may also be stored in one or more memories other than ROM 602 and RAM 603. Processor 601 may also execute various operations of the method flow according to embodiments of the present invention by executing programs stored in said one or more memories.

[0115] According to an embodiment of the present invention, the electronic device 600 may further include an input / output (I / O) interface 605, which is also connected to a bus 604. The electronic device 600 may also include one or more of the following components connected to the input / output (I / O) interface 605: an input section 606 including a keyboard, mouse, etc.; an output section 607 including a cathode ray tube (CRT), liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 608 including a hard disk, etc.; and a communication section 609 including a network interface card such as a LAN card, modem, etc. The communication section 609 performs communication processing via a network such as the Internet. A drive 610 is also connected to the input / output (I / O) interface 605 as needed. A removable medium 611, such as a disk, optical disk, magneto-optical disk, semiconductor memory, etc., is installed on the drive 610 as needed so that computer programs read from it can be installed into the storage section 608 as needed.

[0116] According to embodiments of the present invention, the method flow according to embodiments of the present invention can be implemented as a computer software program. For example, embodiments of the present invention include a computer program product comprising a computer program carried on a computer-readable storage medium, the computer program containing program code for performing the method shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network via communication section 609, and / or installed from removable medium 611. When the computer program is executed by processor 601, it performs the functions defined in the system of the embodiments of the present invention. According to embodiments of the present invention, the systems, devices, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0117] The present invention also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or it may exist independently and not assembled into the device / apparatus / system. The computer-readable storage medium carries one or more programs, which, when executed, implement the method according to the embodiments of the present invention.

[0118] According to embodiments of the present invention, the computer-readable storage medium may be a non-volatile computer-readable storage medium. Examples include, but are not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In the present invention, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0119] For example, according to embodiments of the present invention, a computer-readable storage medium may include the ROM 602 and / or RAM 603 described above and / or one or more memories other than ROM 602 and RAM 603.

[0120] Embodiments of the present invention also include a computer program product comprising a computer program containing program code for performing the methods provided in the embodiments of the present invention. When the computer program product is run on an electronic device, the program code is used to enable the electronic device to implement the fault battery detection method provided in the embodiments of the present invention.

[0121] When the computer program is executed by the processor 601, it performs the functions defined in the system / apparatus of this embodiment of the invention. According to embodiments of the invention, the systems, apparatuses, modules, units, etc., described above can be implemented by computer program modules.

[0122] In one embodiment, the computer program may rely on a tangible storage medium such as an optical storage device or a magnetic storage device. In another embodiment, the computer program may also be transmitted and distributed in the form of signals over a network medium, and downloaded and installed via the communication section 609, and / or installed from the removable medium 611. The program code contained in the computer program can be transmitted using any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination thereof.

[0123] According to embodiments of the present invention, program code for executing the computer programs provided in the embodiments of the present invention can be written in any combination of one or more programming languages. Specifically, these computational programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, languages ​​such as Java, C++, Python, "C", or similar programming languages. The program code can be executed entirely on the user's computing device, partially on the user's device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving remote computing devices, the remote computing device can be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0124] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram or flowchart, and combinations of blocks in a block diagram or flowchart, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions. Those skilled in the art will understand that the features described in the various embodiments of the present invention can be combined and / or combined in various ways, even if such combinations or combinations are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention can be combined and / or combined in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or pairings fall within the scope of this invention.

[0125] The embodiments of the present invention have been described above. However, these embodiments are merely illustrative and not intended to limit the scope of the invention. Although various embodiments have been described above, this does not mean that the measures in the various embodiments cannot be used advantageously in combination. Various substitutions and modifications can be made by those skilled in the art without departing from the scope of the invention, and all such substitutions and modifications should fall within the scope of the invention.

Claims

1. A method for detecting faulty batteries, characterized in that, include: In response to the fact that M battery cells in the battery cluster are not in an equal state, the voltage change value of each of the M battery cells is obtained within a target time period, wherein the target time period is determined based on a single voltage sampling period, the equal state represents the voltage regulation of the battery cluster using a predetermined voltage regulation strategy, and M is a positive integer; In response to the fact that the voltage change values ​​of each of the N cascaded battery cells in the battery cluster are all less than zero, and the voltage change values ​​of each of the MN battery cells in the battery cluster are all greater than zero, a first statistical voltage change value is obtained based on the voltage change values ​​of each of the N battery cells, and a second statistical voltage change value is obtained based on the voltage change values ​​of each of the MN battery cells, wherein N < M and N is a positive integer; Based on the difference between the second statistical voltage change value and the first statistical voltage change value and a predetermined voltage change threshold, a detection result is obtained to indicate whether the battery cluster is in a fault state or a normal state.

2. The method according to claim 1, characterized in that, The start time of the target time period is the time corresponding to the sum of the current sampling time and the preset delay, and the end time of the target time period is the previous sampling time of the current sampling time; or the start time of the target time period is the current sampling time, and the end time of the target time period is the previous sampling time of the current sampling time. The step of obtaining the voltage change values ​​of each of the M battery cells within the target time period includes: For any one of the M battery cells, Obtain the first voltage value of the battery cell at the start time and the second voltage value at the end time; The voltage change value of the battery cell is obtained based on the first voltage value and the second voltage value.

3. The method according to claim 2, characterized in that, The preset delay is greater than the single voltage sampling period.

4. The method according to any one of claims 1 to 3, characterized in that, The first statistical voltage change value is the average of the voltage change values ​​of each of the N cascaded battery cells, and the second statistical voltage change value is the average of the voltage change values ​​of each of the MN battery cells. The step of obtaining a detection result indicating whether the battery cluster is in a fault state or a normal state based on the difference between the second statistical voltage change value and the first statistical voltage change value and a predetermined voltage change threshold includes: If the absolute value of the difference is greater than or equal to the predetermined voltage change threshold, a detection result is obtained to indicate that the battery cluster is in a fault state. If the absolute value of the difference is less than the predetermined voltage change threshold, a detection result is obtained to indicate that the battery cluster is in a normal state.

5. The method according to claim 4, characterized in that, The method further includes: In response to the detection result indicating that the battery cluster is in a fault state, the N cascaded battery cells are determined to be short-circuit faulty batteries.

6. The method according to any one of claims 1 to 3, characterized in that, The predetermined voltage change threshold is determined according to the following operation: Using the loop current equation, the voltage drop of the m-th battery cell in the battery cluster and the average voltage rise of the M-1 battery cells in the battery cluster excluding the m-th battery cell are obtained. The m-th battery cell is considered as a short-circuit fault battery. The loop current equation is constructed based on the topology parameters of the energy storage system in which the battery cluster is located, where m is a positive integer and 1 < m < M. The predetermined voltage change threshold is determined based on the absolute value of the difference between the average voltage rise of the M-1 battery cells and the voltage drop of the m-th battery cell.

7. The method according to claim 6, characterized in that, The method of using the loop current equation to obtain the voltage drop of the m-th battery cell in the battery cluster and the average voltage rise of the M-1 battery cells in the battery cluster excluding the m-th battery cell includes: Using the loop current equation, the first branch current value of the branch where the m-th battery cell is located and the second branch current value of the branch where the M-1 battery cells are located are obtained; The internal resistance value of the m-th battery cell is obtained based on the changes in terminal voltage and terminal current of the m-th battery cell when it switches from constant current charging / discharging state to static state. The open-circuit voltage of the m-th battery cell is obtained based on its internal resistance, terminal voltage, and terminal current under constant current charging / discharging conditions. Based on the open-circuit voltage and internal resistance of the m-th battery cell, the voltage drop of the m-th battery cell and the average voltage rise of the M-1 battery cells are obtained.

8. The method according to claim 6, characterized in that, Determining the predetermined voltage change threshold based on the absolute value of the difference between the average voltage rise of the M-1 battery cells and the voltage drop of the m-th battery cell includes: The initial voltage change threshold is obtained based on the absolute value of the difference between the average voltage rise of the M-1 battery cells and the voltage drop of the m-th battery cell. The braking coefficient is determined based on at least one of the state of charge information, health information, and operating condition information of each of the M battery cells. The predetermined voltage change threshold is determined based on the initial voltage change threshold and the braking coefficient.

9. An electronic device, characterized in that, include: One or more processors; Memory, used to store one or more programs. Wherein, when the one or more programs are executed by the one or more processors, the one or more processors implement the method of any one of claims 1 to 8.

10. A computer-readable storage medium having executable instructions stored thereon, characterized in that, When executed by the processor, this instruction causes the processor to implement the method of any one of claims 1 to 8.

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