An insulation detection circuit, method, device and vehicle of an electric vehicle

Abstract

Embodiments of the present application provide an insulation detection circuit, method and device for an electric vehicle. The detection circuit comprises a first insulation detection circuit. The first insulation detection circuit comprises a voltage dividing circuit, a first detection circuit and a second detection circuit. The voltage dividing circuit comprises at least one voltage dividing resistor, and an input end of the voltage dividing circuit is electrically connected to a first voltage source. The voltage of the first voltage source is less than or equal to a human body safety voltage. An input end of the first detection circuit is electrically connected to an output end of the voltage dividing circuit, and an output end of the first detection circuit is electrically connected to a positive electrode insulation resistor of the electric vehicle. The first detection circuit is configured to detect an insulation performance of the positive electrode insulation resistor of the electric vehicle. An input end of the second detection circuit is electrically connected to the output end of the voltage dividing circuit, and an output end of the second detection circuit is electrically connected to a negative electrode insulation resistor of the electric vehicle. The second detection circuit is configured to detect an insulation performance of the negative electrode insulation resistor of the electric vehicle.

Description

Technical Field

[0001] This application relates to the field of electric vehicles, and more particularly to an insulation detection circuit, method, apparatus, and vehicle for electric vehicles. Background Technology

[0002] With the development of technology and the increasing scarcity of oil resources, new energy vehicles, especially electric vehicles, are becoming increasingly popular among consumers due to their environmental friendliness and low energy consumption. The power source for electric vehicles is the battery pack. Since the battery pack operates at high voltage, the insulation performance of an electric vehicle is a crucial factor in assessing its safety. To meet the insulation requirements of electric vehicles, continuous or intermittent testing of their insulation performance is necessary.

[0003] Most existing electric vehicle insulation tests are conducted after the system is energized with high voltage. This means that if the vehicle's insulation performance is poor, there is a risk of electric shock once the high voltage is applied. Even if the insulation performance problem is detected, an electric shock accident may have already occurred to the passengers. Summary of the Invention

[0004] In view of this, embodiments of this application provide an insulation detection circuit, method, device, and vehicle for electric vehicles to improve the problem of electric shock risk when the vehicle is powered on with high voltage.

[0005] In a first aspect, embodiments of this application provide an insulation detection circuit for an electric vehicle, including a first insulation detection circuit capable of performing insulation detection on the electric vehicle when it is in a scenario where the high voltage is not energized. The first insulation detection circuit includes a voltage divider circuit, a first detection circuit, and a second detection circuit. The voltage divider circuit includes at least one voltage divider resistor, and its input terminal is electrically connected to a first voltage source. The voltage value of the first voltage source is less than or equal to the human body's safe voltage. The input terminal of the first detection circuit is electrically connected to the output terminal of the voltage divider circuit, and its output terminal is electrically connected to the positive insulation resistance of the electric vehicle. The first detection circuit is used to detect the insulation performance of the positive insulation resistance of the electric vehicle. The input terminal of the second detection circuit is electrically connected to the output terminal of the voltage divider circuit, and its output terminal is electrically connected to the negative insulation resistance of the electric vehicle. The second detection circuit is used to detect the insulation performance of the negative insulation resistance of the electric vehicle.

[0006] In one possible implementation of the first aspect, the first voltage source is electrically connected to the auxiliary battery.

[0007] In one possible implementation of the first aspect, the first detection circuit includes at least one voltage divider resistor and at least one controllable switch.

[0008] In one possible implementation of the first aspect, the second detection circuit includes at least one voltage divider resistor and at least one controllable switch.

[0009] In one possible implementation of the first aspect, the first insulation detection circuit further includes a current sampling device and a voltage sampling device. The current sampling device is connected in series with a voltage divider circuit, and the voltage sampling device is electrically connected to both the first detection circuit and the second detection circuit. The voltage sampling device is used to acquire the voltage between the input terminal and ground of the first detection circuit. The voltage sampling device is also used to acquire the voltage between the input terminal and ground of the second detection circuit.

[0010] In one possible implementation of the first aspect, a second insulation detection circuit is also included, which is used to perform insulation detection on the electric vehicle when the electric vehicle is powered on at high voltage.

[0011] In one possible implementation of the first aspect, the voltage divider circuit further includes a diode connected in series with the voltage divider resistor in the voltage divider circuit.

[0012] Secondly, embodiments of this application provide an insulation detection method suitable for electric vehicles. The insulation detection method for electric vehicles is implemented based on the insulation detection circuit provided in the first aspect. The insulation detection method for electric vehicles includes: The first detection circuit is turned on by controlling it to obtain the first voltage value between the input terminal and the ground terminal of the first detection circuit and the first current value of the first detection circuit. Based on the first voltage value and the first current value, the insulation performance of the positive insulation resistance of the electric vehicle is determined.

[0013] The second detection circuit is controlled to be turned on, and the second voltage value between the input terminal and the ground terminal of the second detection circuit and the second current value of the second detection circuit are obtained. Based on the second voltage value and the second current value, the insulation performance of the negative electrode insulation resistance of the electric vehicle is determined.

[0014] Thirdly, embodiments of this application provide an insulation detection device for an electric vehicle, including the insulation detection circuit provided in the first aspect.

[0015] Fourthly, embodiments of this application provide a vehicle including the insulation detection circuit provided in the first aspect.

[0016] The insulation detection circuit provided in this application embodiment can perform insulation detection when the vehicle's high voltage is not energized, thereby effectively preventing electric shock when the high voltage is energized. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a first insulation detection circuit provided in an embodiment of this application; Figure 2 A schematic diagram of an insulation detection circuit for an electric vehicle provided in an embodiment of this application; Figure 3 A schematic diagram of an insulation detection circuit for an electric vehicle provided in an embodiment of this application; Figure 4 This is a schematic diagram of an insulation detection circuit for an electric vehicle provided in an embodiment of this application.

[0019] Label Explanation 100. Insulation detection circuit; 101. Positive insulation resistance; 102. Negative insulation resistance; 103. Power battery; 104. Power circuit; 105. Auxiliary battery; 110. First insulation detection circuit; 111. Voltage divider circuit; 112. First detection circuit; 113. Second detection circuit; 114. First voltage source; 120. Second insulation detection circuit; 121. First voltage divider branch; 122. Second voltage divider branch. Detailed Implementation

[0020] To better understand the technical solution of this application, the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0021] It should be understood that the described embodiments are merely some, not all, of the embodiments in this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without inventive effort are within the scope of protection of this application.

[0022] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms “a,” “the,” and “the” used in the embodiments of this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0023] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0024] like Figure 1 As shown, this application embodiment provides an insulation detection circuit for an electric vehicle, including a first insulation detection circuit 110. The first insulation detection circuit 110 can perform insulation detection on the electric vehicle when it is in a scenario where the high voltage is not energized. The first insulation detection circuit 110 includes a voltage divider circuit 111, a first detection circuit 112, and a second detection circuit 113. The voltage divider circuit 111 includes at least one voltage divider resistor, and its input terminal is electrically connected to a first voltage source 114. The function of the voltage divider circuit 111 is to divide the voltage and limit the current with the first detection circuit 112 and the second detection circuit 113. The first voltage source 114 is a DC voltage source, that is, the first voltage source 114 provides a DC voltage to the first insulation detection circuit 110. The voltage value U1 of the first voltage source 114 is less than or equal to the human body safe voltage. The human body safe voltage is 36V. In one possible implementation, the voltage value U1 of the first voltage source 114 can be 12V, 5V, or 3V. The input terminal of the first detection circuit 112 is electrically connected to the output terminal of the voltage divider circuit 111, and the output terminal of the first detection circuit 112 is electrically connected to the positive insulation resistance 101 of the electric vehicle. The first detection circuit 112 is used to detect the insulation performance of the positive insulation resistance 101 of the electric vehicle. The input terminal of the second detection circuit 113 is electrically connected to the output terminal of the voltage divider circuit 111, and the output terminal of the second detection circuit 113 is electrically connected to the negative insulation resistance 102 of the electric vehicle. The second detection circuit 113 is used to detect the insulation performance of the negative insulation resistance 102 of the electric vehicle.

[0025] In this embodiment, the first insulation detection circuit 110 can detect the insulation performance of the electric vehicle when the high voltage is not energized. The first detection circuit 112 detects the insulation resistance Rp of the positive terminal of the electric vehicle, and the second detection circuit 113 detects the insulation resistance Rn of the negative terminal of the electric vehicle. The first insulation detection circuit 110 in this embodiment is powered by a power source with a voltage lower than that of the human body, thereby realizing the detection of the insulation performance of the electric vehicle under low voltage conditions. Therefore, the first insulation detection circuit 110 provided in this embodiment can operate before the high voltage of the electric vehicle is energized, thereby reducing the risk of electric shock from high voltage energization.

[0026] like Figure 2As shown, in one embodiment of this application, the electric vehicle includes a power battery 103, a positive controllable switch K1, a negative controllable switch K2, and a power circuit 104. The power battery 103 refers to a battery that provides power to the electric vehicle. The output voltage of the power battery 103 is generally high voltage. The positive terminal of the power battery 103 is electrically connected to the power circuit via the positive controllable switch, and the negative terminal of the power battery 103 is electrically connected to the power circuit via the negative controllable switch. The positive controllable switch K1 is used to control the electrical connection between the positive terminal of the power battery 103 and the power circuit 104, and the negative controllable switch K2 is used to control the electrical connection between the negative terminal of the power battery 103 and the power circuit 104. The power circuit 104 refers to a circuit that provides power to drive the electric vehicle.

[0027] like Figure 2 As shown, in one possible implementation of this embodiment, the positive terminal of the power battery 103 is electrically connected to one end of the positive controllable switch K1, and the other end of the positive controllable switch K1 is electrically connected to the output terminal of the first detection circuit. Therefore, the first detection circuit 112 can detect the insulation performance of the positive insulation resistance 101 on the positive controllable switch side.

[0028] The negative terminal of the power battery 103 is electrically connected to one end of the negative terminal controllable switch K2, and the other end of the negative terminal controllable switch K2 is electrically connected to the output terminal of the second detection circuit 113. Therefore, the second detection circuit 113 can detect the insulation performance of the negative terminal insulation resistance 102 on the side of the negative terminal controllable switch K2.

[0029] In one possible implementation, the positive controllable switch K1 is a relay switch, and the negative controllable switch K2 is a relay switch.

[0030] In this embodiment of the application, "the electric vehicle is not powered by high voltage" means that the power battery 103 and the power circuit 104 are disconnected, that is, the positive controllable switch K1 and the negative controllable switch K2 are in the open state.

[0031] It should be noted that the positive insulation resistance Rp in this embodiment refers to the equivalent insulation resistance between the vehicle body shell and the positive output line of the power battery, and is not a real resistive device. This equivalent resistance can be composed of various insulating materials. Similarly, the negative insulation resistance Rn in this embodiment refers to the equivalent insulation resistance between the vehicle body shell and the negative output line of the power battery, and is not a real resistive device. This equivalent resistance can be composed of various insulating materials. Therefore, node 1 and node 2 are not the same node; node 3 and node 4 are also not the same node.

[0032] like Figure 2As shown, in one embodiment of this application, the first voltage source 114 is electrically connected to the auxiliary battery 105. That is, the auxiliary battery 105 provides power to the first voltage source 114. The auxiliary battery 105 refers to a battery that provides power to the control system of an electric vehicle, such as a 12V storage battery. In one possible implementation, the first voltage source 114 includes a DC-DC conversion circuit. The first voltage source 114 is capable of converting the voltage of the auxiliary battery into a voltage value U1 of the first voltage source through the DC-DC conversion circuit.

[0033] In this embodiment, the auxiliary battery 105 provides power to the first voltage source 114, enabling the first voltage source 114 to work independently without the power battery 103 or the power circuit 104. This allows the insulation performance of the electric vehicle to be detected when the electric vehicle is not powered by the high voltage.

[0034] like Figure 3 As shown, in one embodiment of this application, the first detection circuit 112 includes at least one voltage divider resistor R2 and at least one controllable switch M1. In the first detection circuit 112, at least one voltage divider resistor R2 and at least one controllable switch M1 are connected in series. For example, if the first detection circuit 112 includes one voltage divider resistor R2 and one controllable switch M1, then the voltage divider resistor R2 and the controllable switch M1 are connected in series. The first detection circuit 112, including one voltage divider resistor R2 and one controllable switch M1, can simplify the circuit structure and reduce the number of circuit components.

[0035] For example, in the first detection circuit 112, there are multiple voltage divider resistors and at least one controllable switch. The multiple voltage divider resistors are connected in series in sequence and in series with the at least one controllable switch. The first detection circuit, including multiple voltage divider resistors and at least one controllable switch, can reduce the voltage division pressure of a single voltage divider resistor and a single controllable switch, thereby reducing the heat generated by a single voltage divider resistor and a single controllable switch, which is beneficial for heat dissipation and for controlling product costs.

[0036] like Figure 4 As shown, in one possible implementation of this embodiment, the first detection circuit 112 further includes a diode D2. In the first detection circuit 112, the diode D2 can prevent the current of the first detection circuit 112 from flowing backward, thereby protecting the voltage source of the first insulation detection circuit 110.

[0037] In one possible implementation of this embodiment, the controllable switch M1 in the first detection circuit 112 is a MOS transistor. The control terminal of this MOS transistor is implemented by a controller or control circuit, and the controller or control circuit is initially powered by an auxiliary battery.

[0038] like Figure 3As shown, in one embodiment of this application, the second detection circuit 113 includes at least one voltage divider resistor R3 and at least one controllable switch M2. In the second detection circuit 113, at least one voltage divider resistor R3 and at least one controllable switch M2 are connected in series. For example, if the second detection circuit 113 includes one voltage divider resistor R3 and one controllable switch M2, then the voltage divider resistor R3 and the controllable switch M2 are connected in series. The second detection circuit 113, including one voltage divider resistor R3 and one controllable switch M2, simplifies the circuit structure and reduces the number of circuit components.

[0039] For example, in the second detection circuit 113, there are multiple voltage divider resistors and at least one controllable switch. The multiple voltage divider resistors are connected in series in sequence and in series with the at least one controllable switch. The second detection circuit, including multiple voltage divider resistors and at least one controllable switch, can reduce the voltage division pressure of a single voltage divider resistor and a single controllable switch, thereby reducing the heat generated by a single voltage divider resistor and a single controllable switch, which is beneficial for heat dissipation and for controlling product costs.

[0040] like Figure 4 As shown, in one possible implementation of this embodiment, the second detection circuit 113 further includes a diode D3. In the second detection circuit 113, the diode D3 can prevent the current of the second detection circuit 113 from flowing backward, thereby protecting the voltage source of the second insulation detection circuit.

[0041] In one possible implementation of this embodiment, the controllable switch M2 in the second detection circuit 113 is a MOS transistor. The control terminal of this MOS transistor is implemented by a controller or control circuit, and the controller or control circuit is initially powered by an auxiliary battery.

[0042] In one possible implementation, the control signal of the control terminal of the controllable switch M1 in the first detection circuit 112 and the control signal of the control terminal of the controllable switch M2 in the second detection circuit 113 can be provided by the same controller, but their control signals are not synchronized. For example, when the controllable switch M1 in the first detection circuit 112 is on, the controllable switch M2 in the second detection circuit 113 is off. When the controllable switch M2 in the second detection circuit 113 is on, the controllable switch M1 in the first detection circuit 112 is off.

[0043] In one embodiment of this application, the first insulation detection circuit 110 further includes a current sampling device A1 and a voltage sampling device V1. The current sampling device A1 is connected in series with the voltage divider circuit 110, and the voltage sampling device V1 is electrically connected to both the first detection circuit and the second detection circuit. The voltage sampling device V1 is used to collect the voltage between the input terminal and ground of the first detection circuit 112. The voltage sampling device V1 is also used to collect the voltage between the input terminal and ground of the second detection circuit 113.

[0044] In one embodiment of this application, the current sampling device A1 can be a current sensor or an ammeter. The voltage sampling device V1 can be a voltage sensor or a voltmeter.

[0045] The VCU (Vehicle Control Unit) or insulation detection controller of an electric vehicle can determine the insulation performance of the electric vehicle based on the sampling current of the current sampling device A1 and the sampling voltage of the voltage sampling device V1.

[0046] like Figure 4 As shown, in one embodiment of this application, the voltage divider circuit 101 in the first insulation detection circuit 110 further includes a diode D1, which is connected in series with the voltage divider resistor in the voltage divider circuit.

[0047] Diode D1 has single-phase conduction capability. Diode D1 can prevent the current in the voltage divider circuit from flowing backward, thereby protecting the first voltage source.

[0048] like Figure 3 or Figure 4 As shown, the insulation detection circuit 100 also includes a second insulation detection circuit 120, which is used to perform insulation detection on the electric vehicle when the electric vehicle is powered on at high voltage.

[0049] The second insulation detection circuit 120 can continuously or intermittently detect the insulation performance of the electric vehicle after the high voltage is applied, thereby ensuring that the insulation performance of the electric vehicle is promptly fed back to the passengers after the high voltage is applied.

[0050] like Figure 3 or Figure 4As shown, in one implementation of this embodiment, the second insulation detection circuit 120 includes a first voltage divider branch 121 and a second voltage divider branch 122. One end of the first voltage divider branch 121 is connected to the positive terminal of the power battery 103, and the other end is connected to ground. The first voltage divider branch 121 includes voltage divider resistors R4 and R5 connected in series, and at least one controllable switch M3. One end of the second voltage divider branch 122 is connected to the negative terminal of the power battery 103, and the other end is connected to ground. The second voltage divider branch 122 includes voltage divider resistors R6 and R7 connected in series, and at least one controllable switch M4.

[0051] The second insulation detection circuit 120 further includes a first voltage sampling device V2 and a second voltage sampling device V3. One end of the first voltage sampling device V2 is electrically connected to a voltage divider node in the first voltage divider branch 121, and the other end is electrically connected to ground. One end of the second voltage sampling device V3 is electrically connected to a voltage divider node in the second voltage divider branch 122, and the other end is electrically connected to ground. A voltage divider node refers to the node between two voltage divider resistors.

[0052] The second insulation detection circuit 120 further includes: a first voltage-stabilizing capacitor Cp, a second voltage-stabilizing capacitor Cn, a first shunt resistor R7, a first shunt controllable switch M5, a second shunt resistor R8, and a second shunt controllable switch M6. One end of the first voltage-stabilizing capacitor Cp is electrically connected to the positive terminal of the power battery, and the other end of the first voltage-stabilizing capacitor Cp is electrically connected to ground. One end of the second voltage-stabilizing capacitor Cn is electrically connected to the negative terminal of the power battery 103, and the other end of the second voltage-stabilizing capacitor Cn is electrically connected to ground. The first shunt resistor R7 and the first shunt controllable switch M5 are connected in series, with one end of the series branch formed by the two connected to the positive terminal of the power battery 103 and the other end of the series branch formed by the two connected to ground. The second shunt resistor R8 and the second shunt controllable switch M6 are connected in series, with one end of the series branch formed by the two connected to the negative terminal of the power battery 103 and the other end of the series branch formed by the two connected to ground.

[0053] The second insulation detection circuit 120 is also electrically connected to the positive insulation resistor Rp and the negative insulation resistor Rn, respectively.

[0054] This application also provides an insulation detection method suitable for electric vehicles. The insulation detection method for electric vehicles is implemented based on the insulation detection circuit provided in the foregoing embodiments. The insulation detection method for electric vehicles includes: S100, control the first detection circuit to be turned on, obtain the first voltage value between the input terminal and the ground terminal of the first detection circuit, the first current value of the first detection circuit, and determine the insulation performance of the positive electrode insulation resistance of the electric vehicle based on the first voltage value and the first current value.

[0055] In step S100, control M1 is turned on and M2 is turned off. The first current value is obtained using the current sampling device A1, and the first voltage value is obtained using the voltage sampling device V1. For example, if the first voltage value is less than or equal to a first preset threshold, and the first current value is greater than or equal to a second preset threshold, it is determined that there is a problem with the insulation performance of the positive electrode insulation resistance. At this time, an insulation detection alarm indication needs to be issued, such as illuminating the positive electrode insulation detection warning sign or issuing a warning sound.

[0056] S200 controls the second detection circuit to be turned on, obtains the second voltage value between the input terminal and the ground terminal of the second detection circuit and the second current value of the second detection circuit, and determines the insulation performance of the negative electrode insulation resistance of the electric vehicle based on the second voltage value and the second current value.

[0057] In step S200, control M2 is turned on and M1 is turned off. The second current value is obtained using the current sampling device A1, and the second voltage value is obtained using the voltage sampling device V1. For example, if the first voltage value is less than or equal to a third preset threshold, and the first current value is greater than or equal to a fourth preset threshold, it is determined that there is a problem with the insulation performance of the negative electrode insulation resistance. At this time, an insulation detection alarm indication needs to be issued, such as illuminating the negative electrode insulation detection warning sign or issuing a warning sound.

[0058] In one embodiment of this application, the insulation testing method for an electric vehicle further includes: insulation performance testing after the electric vehicle is powered on by high voltage. At this time, the electric vehicle's controller controls M1 and M2 to disconnect, and K1 and K2 to close. The specific steps of the insulation testing method can be as follows: S300: Control the first voltage divider branch 121 and the second voltage divider branch 122 to conduct, obtain the third voltage value between the voltage divider node in the first voltage divider branch 121 and the ground terminal, and obtain the fourth voltage value between the voltage divider node in the second voltage divider branch 122 and the ground terminal. Based on the third and fourth voltage values, determine the insulation performance of the vehicle's positive electrode insulation resistance, and based on the fourth voltage value, determine the insulation performance of the vehicle's negative electrode insulation resistance.

[0059] The third voltage value can be obtained through the first voltage sampling device V2, and the fourth voltage value can be obtained through the second voltage sampling device V3. When the third voltage value is less than or equal to the fifth preset threshold, it is determined that the insulation performance of the positive electrode insulation resistance has a problem. At this time, an insulation detection alarm indication needs to be issued, such as illuminating the positive electrode insulation detection warning sign or issuing a warning sound. When the fourth voltage value is less than or equal to the sixth preset threshold, it is determined that the insulation performance of the negative electrode insulation resistance has a problem. At this time, an insulation detection alarm indication needs to be issued, such as illuminating the negative electrode insulation detection warning sign or issuing a warning sound.

[0060] In one possible implementation, the detection method also includes: S400: If an insulation test fails when the electric vehicle is not energized under high voltage, then high voltage energizing is prohibited. This prevents electric shock accidents caused by applying high voltage.

[0061] In this step, if either the positive or negative insulation resistance is faulty during the insulation test when the electric vehicle is not powered on, then high-voltage power-on is prohibited to avoid electric shock accidents caused by high-voltage power-on.

[0062] If the insulation resistance tests of both the positive and negative terminals show problems when the electric vehicle is not powered on, then high-voltage power-on should be prohibited to avoid electric shock accidents. At the same time, this can prevent short circuits between the positive and negative terminals of the power battery from burning out the internal fuse of the BMS, thereby preventing the fault from escalating and reducing maintenance costs.

[0063] S500: If an insulation test fails when an electric vehicle is powered on at high voltage, the power should be immediately switched off.

[0064] In this step, when the electric vehicle is powered on at high voltage and in a stationary charging state, if the insulation detection of both the positive and negative insulation resistances fails and the discharge current of the power battery exceeds the fault threshold, the power should be immediately disconnected. This can prevent a short circuit between the positive and negative terminals of the power battery from burning out the internal fuse of the BMS, thereby preventing the fault from escalating and reducing maintenance costs.

[0065] S600: After the electric vehicle is powered on with high voltage, if conditions a1), b1), and c1) are detected to be present simultaneously during driving or charging, a fault report should be made. After receiving the fault warning, the service center needs to schedule an inspection with the user to check for wire harness cuts, intermittent high voltage short circuits with the vehicle body, etc.

[0066] a1) The duration for which the third or fourth voltage value is equal to zero is T1, for example, T1 = 1ms; b1) Multiple times within a power-on cycle or a power-on cycle lasting for a duration of T2, for example, T2=10s (or T2 is to be determined by TBD). c1) This occurred in all three consecutive power-on cycles.

[0067] Using this step can achieve the following effects: In driving or charging scenarios, if there is an intermittent short circuit between the high-voltage wiring harness and the vehicle body, the short circuit point may generate sparks that ignite surrounding flammable materials. At the same time, in this scenario, the insulation monitoring function may not be able to identify the fault, and the overall electrical working status of the vehicle is relatively complex. This strategy may have the risk of interference and misjudgment. However, by contacting users for inspection through fault warning and the back-end appointment of the service center, it is more acceptable and can also help customers eliminate potential risks in advance.

[0068] S700: If a collision fault is detected during driving or charging, in accordance with GB18384 regulations, the high voltage will be lowered first. After the high voltage is lowered, if all of the following conditions a2), b2), c2), d), and e) are met, the high voltage will be restored, and the vehicle can be moved according to the user's instructions. a2) Collision fault flag = collision; b2) The brake pedal is depressed; c2) The insulation test of the positive electrode insulation resistance showed no fault. d) The insulation resistance of the negative electrode was tested and found to be fault-free; e) The vehicle has no other faults that prohibit access to high voltage.

[0069] This procedure achieves the following results: As required by regulations, a high voltage is applied to the entire vehicle after a collision, causing a loss of power and rendering the vehicle immobile. If vehicle A is struck by vehicle B, vehicle A sustains minor damage and poses no safety risk, but vehicle B is severely damaged and has caught fire. This strategy helps vehicle A leave the danger zone, reducing accident losses.

[0070] It should be noted that the first preset threshold, second preset threshold, third preset threshold, fourth preset threshold, fifth preset threshold, sixth preset threshold, and fault threshold in the embodiments of this application are all determined by technicians based on the equivalent value of the positive / negative insulation resistance of the vehicle and the safety threshold, and are not limited here.

[0071] Furthermore, in this embodiment, apart from the logical order between steps, the execution order of the remaining steps is not limited. For example, the execution order of steps S100, S200, and S300 in this embodiment is not sequential. Similarly, the execution order of steps S400, S500, S600, and S700 is also not sequential.

[0072] This application also provides an insulation detection device for electric vehicles, including the insulation detection circuit provided in the foregoing embodiments.

[0073] The insulation testing device provided in this application embodiment can effectively test the insulation performance of a vehicle, thereby improving vehicle safety.

[0074] This application also provides a vehicle that includes the insulation detection circuit provided in any of the foregoing embodiments; and / or the insulation detection method of the vehicle is the insulation detection method provided in any of the foregoing embodiments.

[0075] Using the vehicle provided in this application embodiment, the insulation performance of the vehicle can be effectively tested, thereby improving the vehicle's safety.

[0076] The same or similar parts between the various embodiments in this specification can be referred to mutually. In particular, the device embodiments and terminal embodiments are basically similar to the method embodiments, so the description is relatively simple, and the relevant parts can be referred to the description in the method embodiments.

Claims

1. An insulation detection circuit for an electric vehicle, characterized in that, The first insulation detection circuit includes a first insulation detection circuit capable of performing insulation detection on the electric vehicle when the electric vehicle is in a scenario where the high voltage is not energized. The first insulation detection circuit includes: A voltage divider circuit includes at least one voltage divider resistor, and the input terminal of the voltage divider circuit is electrically connected to a first voltage source; the voltage value of the first voltage source is less than or equal to the human body safe voltage. A first detection circuit is used to detect the insulation performance of the positive insulation resistance of the electric vehicle. The input terminal of the first detection circuit is electrically connected to the output terminal of the voltage divider circuit, and the output terminal of the first detection circuit is electrically connected to the positive insulation resistance of the electric vehicle. The second detection circuit has its input terminal electrically connected to the output terminal of the voltage divider circuit, and its output terminal electrically connected to the negative insulation resistance of the electric vehicle. The second detection circuit is used to detect the insulation performance of the negative insulation resistance of the electric vehicle.

2. The insulation detection circuit according to claim 1, characterized in that, The first voltage source is electrically connected to the auxiliary battery.

3. The insulation detection circuit according to claim 1, characterized in that, The first detection circuit includes at least one voltage divider resistor and at least one controllable switch.

4. The insulation detection circuit according to claim 1, characterized in that, The second detection circuit includes at least one voltage divider resistor and at least one controllable switch.

5. The insulation detection circuit according to claim 1, characterized in that, The first insulation detection circuit further includes a current sampling device and a voltage sampling device; the current sampling device is connected in series with the voltage divider circuit, and the voltage sampling device is electrically connected to the first detection circuit and the second detection circuit respectively. The voltage sampling device is used to collect the voltage between the input terminal and the ground terminal of the first detection circuit; the voltage sampling device is used to collect the circuit between the input terminal and the ground terminal of the second detection circuit.

6. The insulation detection circuit according to claim 1, characterized in that, It also includes a second insulation detection circuit, which is used to perform insulation detection on the electric vehicle when the electric vehicle is in a scenario where it is powered on at high voltage.

7. The insulation detection circuit according to claim 1, characterized in that, The voltage divider circuit also includes a diode, which is connected in series with the voltage divider resistor in the voltage divider circuit.

8. An insulation testing method suitable for electric vehicles, characterized in that, The insulation detection method for the electric vehicle is implemented based on the insulation detection circuit according to any one of claims 1-7, and the insulation detection method for the electric vehicle includes: The first detection circuit is turned on by controlling it to obtain a first voltage value between the input terminal and the ground terminal of the first detection circuit and a first current value of the first detection circuit. Based on the first voltage value and the first current value, the insulation performance of the positive insulation resistance of the electric vehicle is determined. The second detection circuit is turned on by controlling it to obtain the second voltage value between the input terminal and the ground terminal of the second detection circuit and the second current value of the second detection circuit. Based on the second voltage value and the second current value, the insulation performance of the negative electrode insulation resistance of the electric vehicle is determined.

9. An insulation testing device for electric vehicles, characterized in that, Includes the insulation detection circuit according to any one of claims 1-7.

10. A vehicle, characterized in that, Includes the insulation detection circuit as described in any one of claims 1-7.

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