Battery leakage protection method and device

Abstract

The invention is suitable for the technical field of battery insulation detection and protection, and particularly relates to a battery leakage protection method and device. According to the method, a known resistor is connected to a positive and negative electrode ground resistor in parallel, so that a second resistance value, namely a resistance value after the positive electrode ground resistor is connected with a first parallel resistor in parallel, can be accurately calculated, and the resistance value of the positive electrode ground resistor is compared with the resistance value of the first parallel resistor. Whether the real insulation resistance of the battery to the ground is too large or the protection grounding wire is lost can be determined, under the normal condition, the highest second resistance value does not exceed the resistance value of the first parallel resistor, when the second resistance value is equal to the resistance value of the first parallel resistor, the resistance value of the positive electrode to the ground resistor is represented to be infinite, and under the abnormal condition, the resistance value of the positive electrode to the ground resistor is represented to be infinite. The resistance value of the second resistor exceeds the resistance value of the first parallel resistor, abnormity caused by loss of the protection grounding wire can be determined, the insulation monitoring precision is improved, and the false alarm condition of battery detection in the high-voltage energy storage system is avoided.

Description

Technical Field

[0001] The present application is applicable to the technical field of battery insulation detection and protection, and in particular, to a battery leakage protection method and device. Background Art

[0002] In recent years, with the continuous updating and upgrading of energy systems, renewable energy, led by solar energy and wind energy, has been widely used. Since this type of energy is greatly affected by the weather and is unstable, energy storage technology plays a key role.

[0003] In high-voltage battery-powered systems, leakage may occur due to factors such as wire aging and high environmental humidity, leading to various safety problems. When the battery fails due to leakage, electric shock, fire and other safety problems may occur, seriously affecting the safety of life and property. Therefore, insulation and arc detection are crucial design links. In order to ensure the safe operation of the high-voltage battery system, comprehensive safety management of the battery system is required.

[0004] At present, the existing battery management system (BMS) only has insulation detection function, and does not include arc detection on the battery side. Therefore, when an arc occurs in the output of the battery, it cannot effectively feedback to the BMS and make a judgment. In the long run, it may cause safety problems such as electric shock or fire due to aging of the line. In addition, the existing insulation detection module is generally integrated on the main control module of the BMS, and is connected to the positive and negative poles of the battery pack and the ground of the shell through wires. When the connected wiring harness is aged or the circuit is broken due to poor contact, the detected insulation value will be infinite, and leakage cannot be detected at this time. At this time, the reliability of insulation detection cannot be guaranteed.

[0005] Therefore, how to improve the insulation monitoring accuracy to avoid false alarms caused by inaccurate battery detection in high-voltage energy storage systems has become an urgent problem to be solved. Summary of the invention

[0006] In view of this, an embodiment of the present application provides a battery leakage protection method and device to solve the problem of how to improve the insulation monitoring accuracy to avoid the problem of false alarms caused by inaccurate battery detection in a high-voltage energy storage system.

[0007] In a first aspect, an embodiment of the present application provides a battery leakage protection method, which is applied to a battery management system of a battery, wherein the positive electrode and the negative electrode of the battery are connected to the outer shell ground of the battery through a positive electrode-to-ground resistor and a negative electrode-to-ground resistor, respectively, a first parallel resistor is connected in parallel to the positive electrode-to-ground resistor, and a second parallel resistor is connected in parallel to the negative electrode-to-ground resistor, and the positive electrode and the negative electrode of the battery are also connected to the outer shell ground through a positive electrode insulation line and a negative electrode insulation line, respectively, and the battery leakage protection method includes: When the positive electrode insulation circuit is turned on and the negative electrode insulation circuit is turned off, obtaining a first current value and a first resistance value of the positive electrode insulation circuit, and determining that the product of the first current value and the first resistance value is a first positive electrode voltage; Obtaining a second resistance value after the positive electrode-to-ground resistance and the first parallel resistance are connected in parallel, dividing the first positive electrode voltage by the second resistance value to obtain a second current value, adding the first current value and the second current value to obtain a third current value, and multiplying the third current value by a third resistance value after the negative electrode-to-ground resistance and the second parallel resistance are connected in parallel to obtain a first negative electrode voltage; When the negative electrode insulation circuit is turned on and the positive electrode insulation circuit is turned off, obtaining a fourth current value and a fourth resistance value of the negative electrode insulation circuit, and determining that the product of the fourth current value and the fourth resistance value is the second negative electrode voltage; Dividing the first negative electrode voltage by the third resistance value to obtain a fifth current value, adding the fourth current value and the fifth current value to obtain a sixth current value, and multiplying the sixth current value by the second resistance value to obtain a second positive electrode voltage; The total voltage of the battery is collected, and the second resistance value is calculated according to the first positive electrode voltage, the first negative electrode voltage, the second positive electrode voltage, the second negative electrode voltage and the total voltage. If the second resistance value is greater than the resistance value of the first parallel resistor, it is determined that the protective grounding wire of the battery is missing, and the missing protective grounding wire is used to indicate a leakage alarm.

[0008] In a second aspect, an embodiment of the present application provides a battery leakage protection device, the battery leakage protection device comprising a battery and a battery management system, the positive electrode and the negative electrode of the battery are connected to the outer shell ground of the battery through a positive electrode-to-ground resistor and a negative electrode-to-ground resistor, respectively, a first parallel resistor is connected in parallel to the positive electrode-to-ground resistor, and a second parallel resistor is connected in parallel to the negative electrode-to-ground resistor, and the positive electrode and the negative electrode of the battery are also connected to the outer shell ground through a positive electrode insulation line and a negative electrode insulation line, respectively, and the battery management system is used to implement: When the positive electrode insulation circuit is turned on and the negative electrode insulation circuit is turned off, obtaining a first current value and a first resistance value of the positive electrode insulation circuit, and determining that the product of the first current value and the first resistance value is a first positive electrode voltage; Obtaining a second resistance value after the positive electrode-to-ground resistance and the first parallel resistance are connected in parallel, dividing the first positive electrode voltage by the second resistance value to obtain a second current value, adding the first current value and the second current value to obtain a third current value, and multiplying the third current value by a third resistance value after the negative electrode-to-ground resistance and the second parallel resistance are connected in parallel to obtain a first negative electrode voltage; When the negative electrode insulation circuit is turned on and the positive electrode insulation circuit is turned off, obtaining a fourth current value and a fourth resistance value of the negative electrode insulation circuit, and determining that the product of the fourth current value and the fourth resistance value is the second negative electrode voltage; Dividing the first negative electrode voltage by the third resistance value to obtain a fifth current value, adding the fourth current value and the fifth current value to obtain a sixth current value, and multiplying the sixth current value by the second resistance value to obtain a second positive electrode voltage; The total voltage of the battery is collected, and the second resistance value is calculated according to the first positive electrode voltage, the first negative electrode voltage, the second positive electrode voltage, the second negative electrode voltage and the total voltage. If the second resistance value is greater than the resistance value of the first parallel resistor, it is determined that the protective grounding wire of the battery is missing, and the missing protective grounding wire is used to indicate a leakage alarm.

[0009] Compared with the prior art, the embodiments of the present application have the following beneficial effects: the battery leakage protection method in the present application is applied to a battery management system of a battery, the positive electrode and the negative electrode of the battery are connected to the outer shell ground of the battery through a positive electrode-to-ground resistor and a negative electrode-to-ground resistor, respectively, a first parallel resistor is connected in parallel to the positive electrode-to-ground resistor, and a second parallel resistor is connected in parallel to the negative electrode-to-ground resistor, the positive electrode and the negative electrode of the battery are also connected to the outer shell ground through a positive electrode insulation circuit and a negative electrode insulation circuit, respectively, when the positive electrode insulation circuit is turned on and the negative electrode insulation circuit is turned off, a first current value and a first resistance value of the positive electrode insulation circuit are obtained, and the product of the first current value and the first resistance value is determined to be a first positive electrode voltage; the first positive electrode voltage is divided by a second resistance value of the positive electrode-to-ground resistor and the first parallel resistor in parallel to obtain a second current value, the first current value and the second current value are added to obtain a third current value, and the third current value is added to the negative electrode-to-ground voltage. The first positive electrode voltage is obtained by multiplying the first positive electrode voltage by the third resistance value after the first positive electrode voltage is connected in parallel with the third resistance value of the second parallel resistor to obtain a first negative electrode voltage; when the negative electrode insulation circuit is turned on and the positive electrode insulation circuit is turned off, obtaining a fourth current value and a fourth resistance value of the negative electrode insulation circuit, and determining that the product of the fourth current value and the fourth resistance value is the second negative electrode voltage; dividing the first negative electrode voltage by the third resistance value to obtain a fifth current value, adding the fourth current value and the fifth current value to obtain a sixth current value, and multiplying the sixth current value by the second resistance value to obtain a second positive electrode voltage; collecting the total voltage of the battery, based on the fact that the sum of the first positive electrode voltage and the first negative electrode voltage is equal to the total voltage, and the sum of the second positive electrode voltage and the second negative electrode voltage is equal to the total voltage, calculating the second resistance value, if the second resistance value is greater than the resistance value of the first parallel resistor, it is determined that the protective grounding wire of the battery is missing, and the missing protective grounding wire is used to indicate a leakage alarm.

[0010] In this regard, the second resistance value, that is, the resistance value of the positive electrode-to-ground resistance connected in parallel with the first parallel resistance, can be accurately calculated. By comparing the second resistance value with the resistance value of the first parallel resistance, it can be determined whether the actual insulation impedance of the battery to the ground is too large or the protective grounding wire is missing. Under normal circumstances, the second resistance value should not exceed the resistance value of the first parallel resistance. When the second resistance value is equal to the resistance value of the first parallel resistance, the resistance value of the positive electrode-to-ground resistance is infinite. Under abnormal circumstances, the second resistance value exceeds the resistance value of the first parallel resistance, which can be determined as an abnormality caused by the missing protective grounding wire, thereby improving the insulation monitoring accuracy and avoiding false alarms of battery detection in high-voltage energy storage systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0012] Figure 1 This is a connection diagram of an insulation protection circuit of a battery provided in Example 1 of the present application; Figure 2 It is a flow chart of a battery leakage protection method provided in Embodiment 2 of the present application; Figure 3 This is a connection diagram provided in the second embodiment of the present application in which the positive electrode insulation circuit is turned on and the negative electrode insulation circuit is turned off; Figure 4 This is a connection diagram provided in the second embodiment of the present application in which the negative electrode insulation circuit is turned on and the positive electrode insulation circuit is turned off; Figure 5 It is a flowchart of a battery leakage protection method provided in Example 3 of the present application; Figure 6 This is a connection diagram of an arc detection circuit provided in Embodiment 3 of the present application; Figure 7 It is a structural schematic diagram of a battery leakage protection device provided in Embodiment 4 of the present application; Figure 8 This is a structural diagram of a BMS provided in Example 5 of the present application. DETAILED DESCRIPTION

[0013] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present application. However, it should be clear to those skilled in the art that the present application may also be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present application.

[0014] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, wholes, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or combinations thereof.

[0015] It should also be understood that the term “and / or” used in the specification and appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0016] As used in the specification and appended claims of this application, the term "if" can be interpreted as "when" or "uponce" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "uponce it is determined" or "in response to determining" or "uponce [described condition or event] is detected" or "in response to detecting [described condition or event]", depending on the context.

[0017] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0018] References to "one embodiment" or "some embodiments" etc. described in the specification of this application mean that one or more embodiments of the present application include specific features, structures or characteristics described in conjunction with the embodiment. Therefore, the statements "in one embodiment", "in some embodiments", "in some other embodiments", "in some other embodiments", etc. that appear in different places in this specification do not necessarily refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "including", "comprising", "having" and their variations all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0019] It should be understood that the size of the serial numbers of the steps in the following embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0020] In order to illustrate the technical solution of the present application, a specific embodiment is provided below for illustration.

[0021] like Figure 1 As shown, it is a connection diagram of an insulation protection circuit of a battery provided in the first embodiment of the present application, wherein the positive electrode of the battery is connected to the protective grounding wire (PE) through the positive electrode insulation line, and the positive electrode of the battery is also connected to the battery shell and grounded (i.e., connected to the shell ground) through the positive electrode to ground resistor, and the negative electrode of the battery is connected to PE through the negative electrode insulation line, and the negative electrode of the battery is also connected to the battery shell and grounded (i.e., the shell ground) through the negative electrode to ground resistor, and the grounding is finally through PE. The battery in the embodiment of the present application can be a high-voltage battery, wherein the high-voltage battery is used in the scene of storing electrical energy and is used for subsequent discharge, etc.

[0022] Two resistors (i.e., R11 and R12) are arranged in the positive insulation circuit, and a first control switch S1 is arranged between the two resistors to realize the conduction control of the positive insulation circuit. Two resistors (i.e., R21 and R22) are arranged in the negative insulation circuit, and a second control switch S2 is arranged between the two resistors to realize the conduction control of the negative insulation circuit. Of course, only one resistor may be arranged in the positive insulation circuit or the negative insulation circuit.

[0023] In addition, the positive electrode to ground resistor R p A first parallel resistor R3 is connected in parallel with the negative electrode, and a resistor R n A second parallel resistor R4 is connected in parallel, wherein the resistance value of R3 may be the same as or different from the resistance value of R4, and preferably a resistor with a resistance value at the MR level is used.

[0024] The present application provides a battery leakage protection method, which is applied to a battery management system of a battery, based on the following settings, that is, the positive electrode and the negative electrode of the battery are connected to the outer shell ground of the battery through a positive electrode-to-ground resistor and a negative electrode-to-ground resistor, respectively, a first parallel resistor is connected in parallel to the positive electrode-to-ground resistor, and a second parallel resistor is connected in parallel to the negative electrode-to-ground resistor, and the positive electrode and the negative electrode of the battery are also connected to the outer shell ground through a positive electrode insulation line and a negative electrode insulation line, respectively, such as Figure 2 FIG. 1 is a flow chart of a battery leakage protection method provided in Embodiment 2 of the present application. The battery leakage protection method comprises the following steps: Step S201, when the positive electrode insulation circuit is turned on and the negative electrode insulation circuit is turned off, a first current value and a first resistance value of the positive electrode insulation circuit are obtained, and a product of the first current value and the first resistance value is determined as a first positive electrode voltage.

[0025] In this embodiment, by turning on the positive electrode insulation circuit and disconnecting the negative electrode insulation circuit, it is possible to detect the positive electrode voltage or current of the battery, thereby obtaining a first current value on the positive electrode insulation circuit. In addition, the resistance on the positive electrode insulation circuit is a known quantity, that is, the first resistance value can be obtained, thereby obtaining the voltage on the positive electrode insulation circuit (that is, the first positive electrode voltage, that is, the voltage divided by the battery on the positive electrode circuit at this time).

[0026] Optionally, obtaining a first current value of the positive electrode insulation circuit includes: Collecting a first voltage value of the positive electrode insulation line through a first isolation operational amplifier circuit; The first voltage value is divided by the resistance value of the resistor on the positive electrode insulation line to obtain a first current value.

[0027] Among them, an isolated operational amplifier circuit is used to collect voltage to obtain current. Since current detection on the positive insulation line is more difficult, compared with collecting current, collecting voltage can quickly and effectively reflect the current situation of the positive insulation line.

[0028] Optionally, a first insulation resistor and a second insulation resistor are provided in series on the positive electrode insulation circuit, and a first voltage value of the positive electrode insulation circuit is collected by a first isolation operational amplifier circuit, including: Collecting a first divided voltage value on the second insulation resistor by a first isolation operational amplifier circuit; Dividing the first voltage division value by the resistance value of the second insulation resistor to obtain a first division result; Adding the resistance value of the first insulation resistor and the resistance value of the second insulation resistor to obtain a first addition result; The first division result is multiplied by the first addition result to obtain a first voltage value.

[0029] Among them, two resistors can be set on the positive insulation line, one resistor can be used as a reference resistor, that is, the resistance value can be larger, and the other resistor can be used as a sampling resistor, and the sampling resistor can have a smaller resistance value than the reference resistor, thereby improving the accuracy of the voltage collected by the isolation amplifier circuit.

[0030] Optionally, a first control switch is provided between the first insulation resistor and the second insulation resistor, and the first control switch is controlled to be closed so that the positive insulation circuit is turned on, or the first control switch is controlled to be opened so that the positive insulation circuit is turned off.

[0031] The first control switch is arranged between the first insulation resistor and the second insulation resistor to realize the control of the conduction or disconnection of the positive electrode insulation circuit. The switch is arranged between the two resistors to provide reliability for the control of the switch to a certain extent.

[0032] Step S202, obtain the second resistance value of the positive electrode-to-ground resistance and the first parallel resistance in parallel, divide the first positive electrode voltage by the second resistance value to obtain the second current value, add the first current value and the second current value to obtain the third current value, multiply the third current value by the third resistance value of the negative electrode-to-ground resistance and the second parallel resistance in parallel to obtain the first negative electrode voltage.

[0033] Among them, the second current value represents the current from the positive electrode of the battery to the outer casing ground through the line in which the positive electrode-to-ground resistance and the first parallel resistor are connected in parallel. The sum of the first current value and the second current value represents the current of the positive electrode of the battery. Since the positive and negative electrode currents are equal, the third current value represents the current from the negative electrode of the battery to the outer casing ground through the line in which the negative electrode-to-ground resistance and the second parallel resistor are connected in parallel. The third current value is then multiplied by the third resistance value after the negative electrode-to-ground resistance and the second parallel resistor are connected in parallel to obtain a voltage (i.e., the first negative electrode voltage, which represents the voltage divider on the negative electrode of the battery at this time).

[0034] It can be seen that the sum of the first positive electrode voltage and the first negative electrode voltage is the total voltage of the battery.

[0035] like Figure 3 FIG. 1 is a connection diagram of a positive electrode insulation circuit being turned on and a negative electrode insulation circuit being turned off provided in the second embodiment of the present application, wherein the first control switch S1 is closed, and two resistors R11 and R12 are provided on the positive electrode insulation circuit. Since the resistance values ​​of the resistors are known, the current i2 passing through R11 and R12 can be obtained by collecting the voltage on any one of the resistors. Specifically, the voltage U across the resistor R12 is collected. sp , and then the first positive electrode voltage and the first negative electrode voltage are calculated using the following formula: ; ; ; ; Finally, the calculation is: .

[0036] in, Characterizes the second resistance value after the positive electrode to ground resistance and the first parallel resistance are connected in parallel, Characterizes the third resistance value after the negative electrode to ground resistance and the second parallel resistance are connected in parallel, Characterizes the total voltage, Characterizes the resistance of the positive electrode to ground. R11 represents the resistance value of the resistor R11, and R12 represents the resistance value of the resistor R12.

[0037] Step S203, when the negative electrode insulation circuit is turned on and the positive electrode insulation circuit is turned off, obtaining a fourth current value and a fourth resistance value of the negative electrode insulation circuit, and determining that the product of the fourth current value and the fourth resistance value is the second negative electrode voltage.

[0038] In this embodiment, by turning on the negative electrode insulation circuit and disconnecting the positive electrode insulation circuit, it is possible to detect the negative electrode voltage or current of the battery, thereby obtaining the fourth current value on the negative electrode insulation circuit. In addition, the resistance on the negative electrode insulation circuit is a known quantity, that is, the fourth resistance value can be obtained, thereby obtaining the voltage on the negative electrode insulation circuit (that is, the second negative electrode voltage, that is, the divided voltage of the battery on the negative electrode circuit at this time).

[0039] Optionally, obtaining a fourth current value of the negative electrode insulation line includes: Collecting a second voltage value of the negative electrode insulation line through a second isolation operational amplifier circuit; The second voltage value is divided by the resistance value of the resistor on the negative electrode insulation line to obtain a fourth current value.

[0040] Among them, the isolation operational amplifier circuit is used to collect voltage to obtain current. Since the current detection on the negative insulation line is more difficult, compared with collecting current, collecting voltage can quickly and effectively reflect the current situation of the negative insulation line.

[0041] Optionally, a third insulation resistor and a fourth insulation resistor are provided in series on the negative electrode insulation circuit, and a second voltage value of the negative electrode insulation circuit is collected by a second isolation operational amplifier circuit, including: Collecting a second divided voltage value on the fourth insulation resistor by a second isolation operational amplifier circuit; Dividing the second voltage division value by the resistance value of the fourth insulation resistor to obtain a second division result; Adding the resistance value of the third insulation resistor and the resistance value of the fourth insulation resistor to obtain a second addition result; The second division result and the second addition result are multiplied to obtain a second voltage value.

[0042] Among them, two resistors can be set on the negative electrode insulation circuit, one resistor can be used as a reference resistor, that is, the resistance value can be larger, and the other resistor can be used as a sampling resistor, and the sampling resistor can have a smaller resistance value than the reference resistor, thereby improving the accuracy of the voltage collected by the isolation operational amplifier circuit.

[0043] Optionally, a second control switch is provided between the third insulation resistor and the fourth insulation resistor, and the second control switch is controlled to be closed so that the negative electrode insulation circuit is turned on, or the second control switch is controlled to be opened so that the negative electrode insulation circuit is turned off.

[0044] The second control switch is arranged between the third insulation resistor and the fourth insulation resistor to realize the control of the conduction or disconnection of the negative electrode insulation circuit. The switch is arranged between the two resistors to provide reliability for the control of the switch to a certain extent.

[0045] Step S204, dividing the first cathode voltage by the third resistance value to obtain a fifth current value, adding the fourth current value and the fifth current value to obtain a sixth current value, and multiplying the sixth current value by the second resistance value to obtain a second anode voltage.

[0046] Among them, the fifth current value represents the current from the negative electrode of the battery to the outer casing ground through the line in which the negative electrode-to-ground resistance and the second parallel resistor are connected in parallel. The sum of the fifth current value and the fourth current value represents the current of the negative electrode of the battery. Since the positive and negative electrode currents are equal, the sixth current value represents the current from the positive electrode of the battery to the outer casing ground through the line in which the positive electrode-to-ground resistance and the first parallel resistor are connected in parallel. The sixth current value is then multiplied by the second resistance value after the positive electrode-to-ground resistance and the first parallel resistor are connected in parallel to obtain a voltage (i.e., the second positive electrode voltage, which represents the voltage divided on the positive electrode of the battery at this time).

[0047] It can be seen that the sum of the second positive electrode voltage and the second negative electrode voltage is the total voltage of the battery.

[0048] like Figure 4 FIG. 1 is a connection diagram of a negative electrode insulation circuit being turned on and a positive electrode insulation circuit being turned off provided in the second embodiment of the present application, wherein the second control switch S2 is closed, and two resistors R21 and R22 are provided on the negative electrode insulation circuit. Since the resistance values ​​of the resistors are known, the current i4 passing through R21 and R22 can be obtained by collecting the voltage on any one of the resistors. Specifically, the voltage U across the resistor R22 is collected. sn , and then the second positive electrode voltage and the second negative electrode voltage are calculated using the following formula: ; ; ; ; Finally, the calculation is: .

[0049] in, Characterizes the second resistance value after the positive electrode to ground resistance and the first parallel resistance are connected in parallel, Characterizes the third resistance value after the negative electrode to ground resistance and the second parallel resistance are connected in parallel, Characterizes the total voltage, Characterizes the resistance of the positive electrode to ground. R11 represents the resistance value of the resistor R11, and R12 represents the resistance value of the resistor R12.

[0050] There is no order of precedence between the above-mentioned step S201 and step S203, that is, there is no order of precedence between controlling the positive electrode insulation circuit to be turned on and the negative electrode insulation circuit to be turned off and controlling the positive electrode insulation circuit to be turned on, as long as the first positive electrode voltage, the first negative electrode voltage, the second positive electrode voltage and the second negative electrode voltage can be calculated.

[0051] Step S205, collecting the total voltage of the battery, and calculating the second resistance value according to the first positive electrode voltage, the first negative electrode voltage, the second positive electrode voltage, the second negative electrode voltage and the total voltage. If the second resistance value is greater than the resistance value of the first parallel resistor, it is determined that the protective grounding wire of the battery is missing.

[0052] In this embodiment, the absence of the protective grounding wire is used to indicate a leakage alarm.

[0053] According to the above-mentioned sum of the first positive electrode voltage and the first negative electrode voltage being equal to the total voltage, and the sum of the second positive electrode voltage and the second negative electrode voltage being equal to the total voltage, combined with the collected total voltage of the battery, the second resistance value can be calculated.

[0054] Due to R p In parallel with R3, when R p When is ∞, The maximum value is R3, and R3 is a resistor with a certain MR level. Therefore, if the detected >R3, it can be determined that PE is missing and an alarm can be issued.

[0055] In this embodiment, an insulation resistance alarm value and a fault value may be preset. For example, when the insulation resistance is 500Ω≥R≥100Ω, it is an alarm, and when R≤100Ω, it is a fault.

[0056] Optionally, based on the fact that the sum of the first positive electrode voltage and the first negative electrode voltage is equal to the total voltage, and the sum of the second positive electrode voltage and the second negative electrode voltage is equal to the total voltage, the second resistance value is calculated, including: According to the sum of the second positive electrode voltage and the second negative electrode voltage being equal to the total voltage, an expression for the third resistance value is obtained; Substituting the expression of the third resistance value into the equation that the sum of the first positive electrode voltage and the first negative electrode voltage is equal to the total voltage, the expression of the second resistance value is obtained; The second resistance value is calculated according to the values ​​of all parameters in the expression of the second resistance value.

[0057] Among them, during the calculation, based on the fact that the sum of the second positive pole voltage and the second negative pole voltage is equal to the total voltage, an expression for the third resistance value is obtained, and then the third resistance value is substituted into the equation that the sum of the first positive pole voltage and the first negative pole voltage is equal to the total voltage, the expression for the second resistance value can be obtained. Since the total voltage and the resistance values ​​​​other than the resistance to ground are known, the second resistance value can be calculated.

[0058] Based on the above formula, we can know that: ; Substitute the above formula into the following formula: ; get: .

[0059] The embodiment of the present application can accurately calculate the second resistance value, that is, the resistance value of the positive electrode-to-ground resistance connected in parallel with the first parallel resistance. By comparing the second resistance value with the resistance value of the first parallel resistance, it can be determined whether the actual insulation impedance of the battery to the ground is too large or the protective grounding wire is missing. Under normal circumstances, the second resistance value should not exceed the resistance value of the first parallel resistance. When the second resistance value is equal to the resistance value of the first parallel resistance, the resistance value of the positive electrode-to-ground resistance is infinite. Under abnormal circumstances, the resistance value of the second resistance exceeds the resistance value of the first parallel resistance, which can be determined as an abnormality caused by the missing protective grounding wire, thereby improving the insulation monitoring accuracy and avoiding false alarms of battery detection in high-voltage energy storage systems.

[0060] See also Figure 5 , which is a flowchart of a battery leakage protection method provided in Example 3 of the present application. For a database instance, it can be used as a receiving instance or an execution instance. When the database instance is an execution instance, Figure 5 As shown, the battery leakage protection method may include the following steps: Step S501, collecting the discharge current on the main circuit of the power line of the battery in real time through the Hall sensor.

[0061] Step S502, sampling and analyzing the total voltage and the discharge current to obtain analysis results, and judging whether it is an arc according to the analysis results to obtain arc detection results.

[0062] When an arc occurs, voltage and current fluctuations will occur. By analyzing the fluctuations in voltage and current, the battery can be located to determine the size, time and location of the arc. A highly sensitive Hall sensor is connected in series on the power harness of the battery. The Hall sensor converts the current in the main circuit into a voltage signal in a certain proportion. The operational amplifier filters out high-frequency and low-frequency interference from the input voltage signal through a bandpass filter, retaining a 30K-100K signal. The signal after filtering out the clutter will pass through the operational amplifier and then the digital-to-analog conversion module will convert the circuit into an analog signal, and the data will be transmitted to the microcontroller unit (MCU) through IIC.

[0063] Based on the total voltage detection in the above insulation detection, the MCU combines the current and total voltage signals for calculation to identify whether the abnormal point is interference or a real problem. like Figure 6 As shown, this is a connection diagram of an arc detection circuit provided in Example 3 of the present application. The Hall sensor is connected to the main circuit, and is finally transmitted to the MCU through amplification, low-pass filtering, high-pass filtering, re-amplification, and high-precision ADC conversion. The total voltage obtained by the total voltage detection will also be transmitted to the MCU, thereby realizing analysis of the voltage and current signals to detect whether an arc phenomenon occurs.

[0064] Corresponding to the battery leakage protection method in the above embodiment, Figure 7 A structural block diagram of a battery leakage protection device provided in Example 4 of the present application is shown. The battery leakage protection device includes a battery and a battery management system. The main circuit of the battery is connected to a power storage converter (Power Conversion System, PCS) through a power saver to achieve charging and discharging functions.

[0065] exist Figure 7 In the BMS, the system is connected to the battery control unit (Battery Controller Unit, BCU), both of which are important components of the BMS. The MCU carries the calculation of insulation detection, battery total voltage detection, and arc detection. The insulation detection realizes the voltage sampling of the positive / negative insulation line in the battery, and the sampling result is filtered and ADC converted before sending to the MCU. The arc detection realizes the current sampling of the main circuit, and the sampling result is filtered and ADC converted before sending to the MCU. The battery total voltage detection realizes the sampling of the voltage between the positive and negative poles of the battery and sends the sampling result to the MCU. In addition, the MCU is also connected to the relay to realize the control of the on / off of the main circuit. The module communicates with the BCU via serial port, so that the module can send alarm information to the BCU for alarm and other operations.

[0066] Accordingly, the MCU implements all the method steps in the above embodiments. In addition, the MCU can also implement any improved battery leakage protection method in the above embodiments.

[0067] Based on the above device, the embodiment of the present application can achieve the following functions: (1) The device includes at least one high-voltage battery with a housing, a relay, and a BCU in the battery management system. The corresponding connector of the device is connected to the positive electrode (B+) and the negative electrode (B-) of the high-voltage battery, the PE is connected to the housing of the high-voltage battery, and the current transformer is inserted into the power line.

[0068] (2) This device is compatible with simultaneous detection of insulation resistance and arc signal.

[0069] (3) The positive electrode insulation resistance is the impedance of the total positive electrode of the high-voltage battery to the shell ground (earth) (R p ), the negative insulation resistance is the impedance of the total negative electrode of the high-voltage battery to the shell ground (earth) (R n ).

[0070] (4) When testing the insulation resistance, a MΩ resistor is connected in parallel between the positive electrode of the battery and the outer shell, and between the negative electrode of the battery and the outer shell. Combined with the total voltage, the insulation value detected can be limited to the resistance value of the parallel resistor. If the detected resistance value is greater than the resistance value of the parallel resistor, it can be judged that the ground wire is broken.

[0071] (5) The MCU presets an insulation resistance alarm value and a fault value. For example, when the insulation resistance is 500Ω≥R≥100Ω, it is an alarm, and when R≤100Ω, it is a fault.

[0072] (6) Arc detection includes an isolated current transformer, a multi-stage filtering circuit and a digital-to-analog conversion device. The multi-stage filtering removes the noise collected by the current transformer and transmits the effective signal to the MCU through a high-precision digital-to-analog conversion device. The MCU determines whether an arc occurs based on the collected total voltage and current signals.

[0073] (7) Both insulation detection and arc detection require accurate total battery voltage for judgment.

[0074] (8) Whether an insulation alarm or an arc alarm occurs, the MCU of this module can immediately transmit the information to the BCU in the BMS system, and the BCU will issue an alarm prompt.

[0075] (9) When serious arc and insulation faults occur, the MCU directly gives a drive signal to shut down the circuit breaker and relay, cutting off the main circuit power supply.

[0076] (10) This scheme proposes a leakage detection circuit and detection method, which can effectively monitor the leakage situation on the battery side of the high-voltage energy storage system and provide protection for the electrical safety of the battery side.

[0077] Figure 8 This is a schematic diagram of the structure of a BMS provided in Example 5 of this application. Figure 8 As shown, the BMS of this embodiment includes: at least one processor ( Figure 8 Only one is shown in the figure), a memory, and a computer program stored in the memory and executable on at least one processor, wherein when the processor executes the computer program, the steps in any of the above-mentioned battery leakage protection method embodiments are implemented.

[0078] The BMS may include, but is not limited to, a processor and a memory. Those skilled in the art will appreciate that Figure 8 This is only an example of a BMS and does not constitute a limitation on the BMS. The BMS may include more or fewer components than those shown in the figure, or a combination of certain components, or different components. For example, it may also include a network interface, a display screen, and an input device.

[0079] The processor may be a CPU, or other general-purpose processors, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0080] The memory includes a readable storage medium, an internal memory, etc., wherein the internal memory may be the memory of the BMS, and the internal memory provides an environment for the operation of the operating system and computer-readable instructions in the readable storage medium. The readable storage medium may be the hard disk of the BMS, and in other embodiments, it may also be an external storage device of the BMS, for example, a plug-in hard disk, a smart memory card (SmartMediaCard, SMC), a secure digital (SecureDigital, SD) card, a flash card (FlashCard), etc. equipped on the BMS. Furthermore, the memory may also include both an internal storage unit of the BMS and an external storage device. The memory is used to store an operating system, an application program, a boot loader (BootLoader), data, and other programs, such as the program code of a computer program, etc. The memory may also be used to temporarily store data that has been output or is to be output.

[0081] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device is divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated into a processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned device can refer to the corresponding process in the above-mentioned method embodiment, which will not be repeated here. If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, which can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of the above-mentioned method embodiment can be implemented. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may at least include: any entity or device capable of carrying computer program code, recording medium, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium. For example, a USB flash drive, a mobile hard disk, a magnetic disk or an optical disk. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electric carrier signals and telecommunication signals.

[0082] The present application implements all or part of the processes in the above-mentioned method embodiments, and may also be completed through a computer program product. When the computer program product runs on a BMS, the steps in the above-mentioned method embodiments can be implemented when the BMS executes the computer program product.

[0083] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0084] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0085] In the embodiments provided in the present application, it should be understood that the disclosed devices / BMS and methods can be implemented in other ways. For example, the device / BMS embodiments described above are merely schematic. For example, the division of modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0086] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0087] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A battery leakage protection method, characterized in that: The battery leakage protection method is applied to a battery management system of a battery, wherein the positive electrode and the negative electrode of the battery are connected to the outer shell ground of the battery through a positive electrode-to-ground resistor and a negative electrode-to-ground resistor, respectively, a first parallel resistor is connected in parallel to the positive electrode-to-ground resistor, and a second parallel resistor is connected in parallel to the negative electrode-to-ground resistor, and the positive electrode and the negative electrode of the battery are also connected to the outer shell ground through a positive electrode insulation line and a negative electrode insulation line, respectively. The battery leakage protection method comprises: When the positive electrode insulation circuit is turned on and the negative electrode insulation circuit is turned off, obtaining a first current value and a first resistance value of the positive electrode insulation circuit, and determining that the product of the first current value and the first resistance value is a first positive electrode voltage; Obtaining a second resistance value after the positive electrode-to-ground resistance and the first parallel resistance are connected in parallel, dividing the first positive electrode voltage by the second resistance value to obtain a second current value, adding the first current value and the second current value to obtain a third current value, and multiplying the third current value by a third resistance value after the negative electrode-to-ground resistance and the second parallel resistance are connected in parallel to obtain a first negative electrode voltage; When the negative electrode insulation circuit is turned on and the positive electrode insulation circuit is turned off, obtaining a fourth current value and a fourth resistance value of the negative electrode insulation circuit, and determining that the product of the fourth current value and the fourth resistance value is the second negative electrode voltage; Dividing the first negative electrode voltage by the third resistance value to obtain a fifth current value, adding the fourth current value and the fifth current value to obtain a sixth current value, and multiplying the sixth current value by the second resistance value to obtain a second positive electrode voltage; The total voltage of the battery is collected, and the second resistance value is calculated according to the first positive electrode voltage, the first negative electrode voltage, the second positive electrode voltage, the second negative electrode voltage and the total voltage. If the second resistance value is greater than the resistance value of the first parallel resistor, it is determined that the protective grounding wire of the battery is missing, and the missing protective grounding wire is used to indicate a leakage alarm.

2. The battery leakage protection method according to claim 1, characterized in that: The obtaining of the first current value of the positive electrode insulation circuit includes: Collecting a first voltage value of the positive electrode insulation circuit by a first isolation operational amplifier circuit; The first voltage value is divided by the resistance value of the resistor on the positive electrode insulation circuit to obtain a first current value.

3. The battery leakage protection method according to claim 2, characterized in that: The positive electrode insulation circuit is provided with a first insulation resistor and a second insulation resistor in series, and the first voltage value of the positive electrode insulation circuit is collected by the first isolation operational amplifier circuit, including: Collecting a first voltage division value on the second insulation resistor by a first isolation operational amplifier circuit; Dividing the first divided voltage value by the resistance value of the second insulation resistor to obtain a first division result; Adding the resistance value of the first insulation resistor and the resistance value of the second insulation resistor to obtain a first addition result; The first division result is multiplied by the first addition result to obtain a first voltage value.

4. The battery leakage protection method according to claim 3, characterized in that: A first control switch is provided between the first insulation resistor and the second insulation resistor, and the first control switch is controlled to be closed so that the positive insulation circuit is turned on, or the first control switch is controlled to be opened so that the positive insulation circuit is turned off.

5. The battery leakage protection method according to claim 1, characterized in that: The obtaining of a fourth current value of the negative electrode insulation circuit includes: Collecting a second voltage value of the negative electrode insulation circuit by a second isolation operational amplifier circuit; The second voltage value is divided by the resistance value of the resistor on the negative electrode insulation circuit to obtain a fourth current value.

6. The battery leakage protection method according to claim 5, characterized in that: The negative electrode insulation circuit is provided with a third insulation resistor and a fourth insulation resistor in series, and the second voltage value of the negative electrode insulation circuit is collected by the second isolation operational amplifier circuit, including: Collecting a second voltage division value on the fourth insulation resistor by a second isolation operational amplifier circuit; Dividing the second divided voltage value by the resistance value of the fourth insulation resistor to obtain a second division result; Adding the resistance value of the third insulation resistor and the resistance value of the fourth insulation resistor to obtain a second addition result; The second division result and the second addition result are multiplied to obtain a second voltage value.

7. The battery leakage protection method according to claim 6, characterized in that: A second control switch is provided between the third insulation resistor and the fourth insulation resistor, and the second control switch is controlled to be closed so that the negative electrode insulation circuit is turned on, or the second control switch is controlled to be opened so that the negative electrode insulation circuit is turned off.

8. The battery leakage protection method according to claim 1, characterized in that: The second resistance value is calculated based on the fact that the sum of the first positive electrode voltage and the first negative electrode voltage is equal to the total voltage, and the sum of the second positive electrode voltage and the second negative electrode voltage is equal to the total voltage, including: According to the sum of the second positive electrode voltage and the second negative electrode voltage being equal to the total voltage, an expression for the third resistance value is obtained; Substituting the expression of the third resistance value into the equation that the sum of the first positive electrode voltage and the first negative electrode voltage is equal to the total voltage, to obtain the expression of the second resistance value; The second resistance value is calculated according to the values ​​of all parameters in the expression of the second resistance value.

9. The battery leakage protection method according to claim 1, characterized in that: The battery leakage protection method also includes: The discharge current on the main circuit of the power line of the battery is collected in real time by a Hall sensor; Sampling and analyzing the total voltage and the discharge current to obtain analysis results; An arc judgment is performed according to the analysis result to obtain an arc detection result.

10. A battery leakage protection circuit, characterized in that: The battery leakage protection device includes a battery and a battery management system. The positive electrode and the negative electrode of the battery are connected to the outer shell ground of the battery through a positive electrode-to-ground resistor and a negative electrode-to-ground resistor, respectively. A first parallel resistor is connected in parallel to the positive electrode-to-ground resistor, and a second parallel resistor is connected in parallel to the negative electrode-to-ground resistor. The positive electrode and the negative electrode of the battery are also connected to the outer shell ground through a positive electrode insulation line and a negative electrode insulation line, respectively. The battery management system is used to achieve: When the positive electrode insulation circuit is turned on and the negative electrode insulation circuit is turned off, obtaining a first current value and a first resistance value of the positive electrode insulation circuit, and determining that the product of the first current value and the first resistance value is a first positive electrode voltage; Obtaining a second resistance value after the positive electrode-to-ground resistance and the first parallel resistance are connected in parallel, dividing the first positive electrode voltage by the second resistance value to obtain a second current value, adding the first current value and the second current value to obtain a third current value, and multiplying the third current value by a third resistance value after the negative electrode-to-ground resistance and the second parallel resistance are connected in parallel to obtain a first negative electrode voltage; When the negative electrode insulation circuit is turned on and the positive electrode insulation circuit is turned off, obtaining a fourth current value and a fourth resistance value of the negative electrode insulation circuit, and determining that the product of the fourth current value and the fourth resistance value is the second negative electrode voltage; Dividing the first negative electrode voltage by the third resistance value to obtain a fifth current value, adding the fourth current value and the fifth current value to obtain a sixth current value, and multiplying the sixth current value by the second resistance value to obtain a second positive electrode voltage; The total voltage of the battery is collected, and the second resistance value is calculated according to the first positive electrode voltage, the first negative electrode voltage, the second positive electrode voltage, the second negative electrode voltage and the total voltage. If the second resistance value is greater than the resistance value of the first parallel resistor, it is determined that the protective grounding wire of the battery is missing, and the missing protective grounding wire is used to indicate a leakage alarm.

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