Insulation detection circuit, method, and automobile

Abstract

The application provides an insulation detection circuit, method and automobile, comprising a sampling module, a detection module, a first voltage division module, a second voltage division module, a third voltage division module and a fourth voltage division module; the first voltage division module, the second voltage division module, the third voltage division module and the fourth voltage division module are arranged between the positive electrode of the battery end and the ground, between the negative electrode of the battery end and the ground, between the positive electrode of the load end and the negative electrode of the battery end and between the negative electrode of the load end and the negative electrode of the battery end; the sampling module is connected with the first voltage division module, the second voltage division module, the third voltage division module and the fourth voltage division module and is used for collecting the voltage of the first sampling point position under different states; the detection module is connected with the sampling module and is used for performing insulation detection on the battery end and / or the load end according to the voltage collected by the sampling module. According to the scheme, the insulation detection of the load end can be realized when the load end is not connected with the battery end, and the accuracy of the insulation detection is improved.

Description

Technical Field

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

[0002] With the development of new energy vehicles, the voltage of on-board batteries is gradually increasing to meet more driving needs. In existing technologies, to ensure the safety and reliability of new energy vehicles, it is necessary to test their safety protection features, such as the insulation protection between the on-board battery and the vehicle body.

[0003] In the prior art, the Battery Management System (BMS) has an insulation detection function, which can detect the insulation status between the positive terminal of the battery and the vehicle body in real time, as well as the insulation status between the negative terminal of the battery and the vehicle body.

[0004] In the above scheme, the insulation status of the load end cannot be detected when the load end and the battery end are not connected, resulting in low accuracy of insulation detection. Summary of the Invention

[0005] This application provides an insulation detection circuit, method, and automobile, aiming to solve the problem that the insulation status of the load terminal cannot be detected when the load terminal and the battery terminal are not connected, resulting in low accuracy of insulation detection.

[0006] In a first aspect, this application provides an insulation detection circuit, comprising: a sampling module, a detection module, a first voltage divider module, a second voltage divider module, a third voltage divider module, and a fourth voltage divider module; one end of the first voltage divider module is connected to the positive terminal of a battery, and the other end of the first voltage divider module is grounded; one end of the second voltage divider module is connected to the negative terminal of the battery, and the other end of the second voltage divider module is grounded; one end of the third voltage divider module is connected to the positive terminal of a load, and the other end of the third voltage divider module is connected to the negative terminal of the battery; one end of the fourth voltage divider module is connected to the negative terminal of the load, and the other end of the fourth voltage divider module is connected to the negative terminal of the battery; the sampling module is connected to the first voltage divider module, the second voltage divider module, the third voltage divider module, and the fourth voltage divider module. A four-stage voltage divider module is connected to collect the voltage at the first sampling point location under different conditions. These different conditions include: the negative terminal of the battery is in a conductive state along a first path from the second voltage divider module to ground; the first path and the positive terminal of the battery are in a conductive state along a second path from the first voltage divider module to ground; the first path and the positive terminal of the load are in a conductive state along a third path from the third voltage divider module to the negative terminal of the battery; and the first path and the negative terminal of the load are in a conductive state along a fourth path from the fourth voltage divider module to the negative terminal of the battery. A detection module is connected to the sampling module and is used to perform insulation detection on the battery and / or load terminals based on the voltage collected by the sampling module.

[0007] In one possible implementation, the second voltage divider module includes: a first resistor, a second resistor, and a first switch; one end of the first resistor is connected to the negative terminal of the battery, the other end of the first resistor is connected to one end of the second resistor, and the connection point of the first resistor and the second resistor is used as the first sampling point and connected to the sampling module; the other end of the second resistor is connected to one end of the first switch; the other end of the first switch is grounded.

[0008] In one possible implementation, the first voltage divider module includes: a third resistor and a second switch; one end of the third resistor is connected to the positive terminal of the battery, and the other end of the third resistor is connected to one end of the second switch; the other end of the second switch is connected to the other end of the first switch and grounded.

[0009] In one possible implementation, the third voltage divider module includes: a fourth resistor, a fifth resistor, and a third switch; one end of the fourth resistor is connected to the positive terminal of the load terminal, and the other end of the fourth resistor is connected to one end of the third switch; the other end of the third switch is connected to one end of the fifth resistor, and the connection point between the third switch and the fifth resistor is used as a second sampling point and connected to the sampling module; the other end of the fifth resistor is connected to the negative terminal of the battery terminal.

[0010] In one possible implementation, the fourth voltage divider module includes: a sixth resistor, a seventh resistor, and a fourth switch; one end of the sixth resistor is connected to the negative terminal of the load terminal, and the other end of the sixth resistor is connected to one end of the fourth switch; the other end of the fourth switch is connected to one end of the seventh resistor, and the connection point between the fourth switch and the seventh resistor is used as a third sampling point and connected to the sampling module; the other end of the seventh resistor is connected to the negative terminal of the battery terminal.

[0011] In one possible implementation, the insulation detection circuit further includes: a first capacitor, a fifth switch, a sixth switch, a seventh switch, and an eighth resistor; one end of the first capacitor is connected to the positive terminal of the load terminal, and the other end of the first capacitor is connected to the negative terminal of the load terminal; the fifth switch is connected in series in the transmission path between the positive terminal of the battery terminal and the positive terminal of the load terminal; one end of the sixth switch is connected to the positive terminal of the battery terminal, and the other end of the sixth switch is connected to one end of the eighth resistor; the other end of the eighth resistor is connected to the positive terminal of the load terminal; and the seventh switch is connected in series in the transmission path between the negative terminal of the battery terminal and the negative terminal of the load terminal.

[0012] In one possible implementation, at least one switch is an electrical isolation switch, which includes an optocoupler and a photoelectric MOSFET.

[0013] In one possible implementation, at least one switch is a controllable switch, which includes a small signal relay and a reed relay.

[0014] Secondly, this application provides an insulation detection method based on the insulation detection circuit described above. The method includes: controlling a first path to conduct, obtaining a first voltage sampled by a sampling module at a first sampling point; controlling a first path and a second path to conduct, obtaining a second voltage sampled by the sampling module at the first sampling point; controlling a first path and a third path to conduct, obtaining a third voltage sampled by the sampling module at the first sampling point; controlling a first path and a fourth path to conduct, obtaining a fourth voltage sampled by the sampling module at the first sampling point; and performing insulation detection on the battery terminal and / or the load terminal based on the first voltage, the second voltage, the third voltage, and the fourth voltage.

[0015] In one possible implementation, before performing insulation detection on the battery terminal and / or load terminal based on the first voltage, the second voltage, the third voltage, and the fourth voltage, the method further includes: determining whether the fifth switch and the seventh switch are conducting; if they are not conducting, then performing insulation detection on the battery terminal and / or load terminal based on the first voltage, the second voltage, the third voltage, and the fourth voltage; if they are conducting, then the method further includes: performing insulation detection on the battery terminal and / or load terminal based on the first voltage and the second voltage.

[0016] In one possible implementation, determining whether the fifth and seventh switches are on includes: controlling the third path to conduct, obtaining a fifth voltage sampled by the sampling module at the second sampling point; controlling the fourth path to conduct, obtaining a sixth voltage sampled by the sampling module at the third sampling point; calculating the voltage between the positive and negative terminals of the load terminal based on the fifth and sixth voltages; determining whether the voltage between the positive and negative terminals of the load terminal is 0; if it is not 0, determining that the fifth and seventh switches are on; if it is 0, determining that the fifth and seventh switches are off.

[0017] In one possible implementation, the insulation detection of the battery terminal and / or load terminal based on the first voltage, the second voltage, the third voltage, and the fourth voltage includes: establishing a first equation corresponding to the first voltage and a second equation corresponding to the second voltage based on Kirchhoff's laws; establishing a system of equations based on the first and second equations to calculate the equivalent resistance of the positive and negative terminals of the battery terminal; establishing a third equation corresponding to the third voltage based on Kirchhoff's laws and solving the third equation to obtain the equivalent resistance of the positive terminal of the load terminal; establishing a fourth equation corresponding to the fourth voltage based on Kirchhoff's laws and solving the fourth equation to obtain the equivalent resistance of the positive terminal of the load terminal; and performing insulation detection of the battery terminal and / or load terminal based on the equivalent resistance of the positive terminal, the equivalent resistance of the negative terminal, the equivalent resistance of the positive terminal, and the equivalent resistance of the positive terminal of the load terminal.

[0018] Thirdly, this application provides an automobile, including: the insulation detection circuit as described above.

[0019] The insulation detection circuit, method, and automobile provided in this application respectively provide a first voltage divider module, a second voltage divider module, a third voltage divider module, and a fourth voltage divider module between the positive terminal of the battery and ground, between the negative terminal of the battery and ground, between the positive terminal of the load and the negative terminal of the battery, and between the negative terminal of the load and the negative terminal of the battery. A sampling module, connected to a first voltage divider module, a second voltage divider module, a third voltage divider module, and a fourth voltage divider module, acquires the voltage at the first sampling point location under different states. These different states include: the first path from the negative terminal of the battery to ground via the second voltage divider module is conductive; the first path and the second path from the positive terminal of the battery to ground via the first voltage divider module are conductive; the first path and the third path from the positive terminal of the load to the negative terminal of the battery via the third voltage divider module are conductive; and the first path and the negative terminal of the load to the negative terminal of the battery via the fourth voltage divider module are conductive. A detection module, connected to the sampling module, performs insulation detection on the battery and / or load terminals based on the voltage acquired by the sampling module. In this application's solution, when the first path is conducting, it is connected in parallel with the equivalent resistance between the negative terminal of the battery and ground; when the second path is conducting, it is connected in parallel with the equivalent resistance between the positive terminal of the battery and ground. The acquisition module acquires the voltage at the first sampling point when the first path, the first path, and the second path are conducting, respectively. Based on the voltage acquired by the sampling module, the detection module can determine the equivalent resistance between the positive terminal of the battery and ground, and the equivalent resistance between the negative terminal of the battery and ground, enabling insulation detection of the battery terminal. The third and fourth voltage divider modules connect the equivalent resistance between the positive terminal of the load and ground, and the equivalent resistance between the negative terminal of the load and ground, to the battery terminal. The sampling module acquires the voltage at the first sampling point, and the detection module can perform insulation detection of the load terminal based on the voltage acquired by the sampling module. Therefore, this application's solution can still achieve insulation detection of the load terminal when the load terminal and the battery terminal are not connected, improving the accuracy of insulation detection. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0021] Figure 1 This is a schematic diagram of the insulation detection circuit in the related technology provided in this application;

[0022] Figure 2 This is a schematic diagram of an insulation detection circuit provided in Embodiment 1 of this application;

[0023] Figure 3This is a schematic diagram of another insulation detection circuit provided in Embodiment 1 of this application;

[0024] Figure 4 This is a schematic diagram of another insulation detection circuit provided in Embodiment 1 of this application;

[0025] Figure 5 This is a schematic diagram of another insulation detection circuit provided in Embodiment 1 of this application;

[0026] Figure 6 This is a schematic diagram of another insulation detection circuit provided in Embodiment 1 of this application;

[0027] Figure 7 This is a schematic diagram of an insulation detection circuit provided in Embodiment 2 of this application;

[0028] Figure 8 This is a schematic flowchart of an insulation testing method provided in Embodiment 2 of this application.

[0029] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0030] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0031] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0032] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar or related objects or entities and do not necessarily imply a specific order or sequence, unless otherwise indicated. It should be understood that such terms can be used interchangeably where appropriate, for example, to implement the application in a sequence other than those given in the embodiments illustrated or described herein.

[0033] Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover but not exclude inclusion. For example, a product or device that includes a series of components is not necessarily limited to those explicitly listed, but may include other components not explicitly listed or inherent to such product or device. As used in this application, the term "module" means any known or subsequently developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and / or software code capable of performing the functions associated with that element.

[0034] With the development of new energy vehicles, the voltage of on-board batteries is gradually increasing to meet more driving needs. In existing technologies, to ensure the safety and reliability of new energy vehicles, safety protection tests are required before they leave the factory, such as the insulation protection between the on-board battery and the vehicle body.

[0035] In the prior art, the Battery Management System (BMS) has an insulation detection function, which can detect the insulation status between the positive terminal of the battery and the vehicle body in real time, as well as the insulation status between the negative terminal of the battery and the vehicle body.

[0036] Figure 1 This is a schematic diagram of the insulation detection circuit in the related technology provided in this application. Figure 1 As shown, the insulation detection circuit includes an insulation detection module 100 and a switch 101. One end of the insulation detection module 100 is connected to the positive terminal of the battery, and the other end is connected to the negative terminal of the battery. The grounding terminal of the insulation detection module 100 is grounded. One end of the switch 101 is connected to the positive terminal of the battery, and the other end is connected to the negative terminal of the battery.

[0037] In practical applications, switch 101 is used to control the connection between the battery terminal and the load terminal, thereby controlling whether the battery terminal supplies power to the load terminal. For example, switch 101 can be a high-voltage relay. When the high-voltage relay is closed, the vehicle battery supplies power to the load; when the high-voltage relay is open, the vehicle battery stops supplying power to the load.

[0038] To illustrate with a practical scenario, when switch 101 is closed, the load terminal is connected to the battery terminal, and the insulation detection module 100 can detect the insulation status of the battery terminal and the load terminal. However, when switch 101 is open, the load terminal is disconnected from the battery terminal, and while the insulation detection module can detect the insulation status of the battery terminal, it cannot detect the insulation status of the load terminal.

[0039] In the above scheme, the insulation status of the load end cannot be detected when the load end and the battery end are not connected, resulting in low accuracy of insulation detection.

[0040] The technical content provided in this application is intended to solve the aforementioned technical problems in related technologies.

[0041] The technical solutions of this application will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. In the description of this application, unless otherwise expressly specified and limited, the terms should be broadly understood within the art. The embodiments of this application will now be described with reference to the accompanying drawings.

[0042] Example 1

[0043] Figure 2 This is a schematic diagram of an insulation detection circuit provided in Embodiment 1 of this application, as shown below. Figure 2 As shown, this embodiment provides an insulation detection circuit, including: a sampling module 20, a detection module 21, a first voltage divider module 22, a second voltage divider module 23, a third voltage divider module 24, and a fourth voltage divider module 25;

[0044] One end of the first voltage divider module 22 is connected to the positive terminal of the battery, and the other end of the first voltage divider module 22 is grounded; one end of the second voltage divider module 23 is connected to the negative terminal of the battery, and the other end of the second voltage divider module 23 is grounded; one end of the third voltage divider module 24 is connected to the positive terminal of the load, and the other end of the third voltage divider module 24 is connected to the negative terminal of the battery; one end of the fourth voltage divider module 25 is connected to the negative terminal of the load, and the other end of the fourth voltage divider module 25 is connected to the negative terminal of the battery.

[0045] The sampling module 20, connected to the first voltage divider module 22, the second voltage divider module 23, the third voltage divider module 24, and the fourth voltage divider module 25, is used to collect the voltage at the location of the first sampling point under different states. These different states include: the first path from the negative terminal of the battery to ground via the second voltage divider module 23 is in a conductive state; the first path and the second path from the positive terminal of the battery to ground via the first voltage divider module 22 are in a conductive state; the first path and the third path from the positive terminal of the load to the negative terminal of the battery via the third voltage divider module 24 are in a conductive state; and the first path and the fourth path from the negative terminal of the load to the negative terminal of the battery via the fourth voltage divider module 25 are in a conductive state.

[0046] The detection module 21 is connected to the sampling module 20 and is used to perform insulation detection on the battery terminal and / or load terminal based on the voltage collected by the sampling module 20.

[0047] In practical applications, the insulation detection circuit provided in this embodiment can be applied to new energy vehicles, including but not limited to pure electric vehicles and hybrid electric vehicles. In this embodiment, grounding refers to the reference grounding of the new energy vehicle body. The insulation detection circuit essentially detects the insulation status between the positive terminal of the battery and the vehicle body, the negative terminal of the battery and the vehicle body, the positive terminal of the load and the vehicle body, and the negative terminal of the load and the vehicle body.

[0048] In one example, the equivalent resistance values ​​of the four equivalent resistances—Rp1 between the positive terminal of the battery and ground, Rn1 between the negative terminal of the battery and ground, Rp2 between the positive terminal of the load and ground, and Rn2 between the negative terminal of the load and ground—can be detected and compared with preset resistance thresholds. If any of these four equivalent resistance values ​​exceeds the preset threshold, it indicates that the insulation protection of the vehicle body is abnormal. This can be addressed by alerting the user, ensuring their personal safety and improving the safety and reliability of the vehicle.

[0049] In this embodiment, the insulation detection process is divided into four stages. Specifically, in the first stage, the negative terminal of the battery is in a conductive state through the first path from the second voltage divider module 23 to ground, and the sampling module 20 collects the voltage at the first sampling point to obtain the first voltage U1; in the second stage, the first path and the positive terminal of the battery are in a conductive state through the first voltage divider module 22 to ground, and the sampling module 20 collects the voltage at the first sampling point to obtain the second voltage U2; in the third stage, the first path and the positive terminal of the load are in a conductive state through the third voltage divider module 24 to the negative terminal of the battery, and the sampling module 20 collects the voltage at the first sampling point to obtain the third voltage U3; in the fourth stage, the first path and the negative terminal of the load are in a conductive state through the fourth voltage divider module 25 to the negative terminal of the battery, and the sampling module 20 collects the voltage at the first sampling point to obtain the fourth voltage U4.

[0050] Specifically, the first sampling point is located on the first path, and the first path is in a conductive state during the insulation detection process. In the first stage, the first path is conductive, and the first path is equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the first voltage U1. In the second stage, the first path is conductive and the second path is conductive. The second path is equivalently connected in parallel to the equivalent resistance Rp1 between the positive terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the second voltage U2. Based on the first voltage U1 and the second voltage U2 collected by the detection module 20, the detection module 21 can determine the resistance value of the equivalent resistance Rp1 between the positive terminal of the battery and ground and the resistance value of the equivalent resistance Rn1 between the negative terminal of the battery and ground. Therefore, the detection module 21 can perform insulation detection on the battery terminal.

[0051] Based on this, in the third stage, both the first and third paths are connected. The third path is connected in series with the equivalent resistance Rp2 between the positive terminal of the load and ground, and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 acquires the voltage at the first sampling point to obtain the third voltage U3. In the fourth stage, both the first and fourth paths are connected. The fourth path is connected in series with the equivalent resistance Rn2 between the negative terminal of the load and ground, and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 acquires the voltage at the first sampling point to obtain the fourth voltage U4. Based on the third voltage U3 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rp2 between the positive terminal of the load and ground. Similarly, based on the fourth voltage U4 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rn2 between the negative terminal of the load and ground. Therefore, the detection module 21 can perform insulation detection on the load.

[0052] It is understood that in this embodiment, the third voltage divider module 24 and the fourth voltage divider module 25 can connect the equivalent resistance Rp2 between the positive terminal of the load and ground and the equivalent resistance Rn2 between the negative terminal of the load and ground to the battery terminal. The sampling module 20 collects the voltage at the first sampling point, and the detection module 21 can perform insulation detection on the load terminal based on the voltage collected by the sampling module 20. Therefore, the insulation detection circuit in this embodiment can perform insulation detection on the load terminal regardless of whether the battery terminal and the load terminal are connected.

[0053] Optionally, in one possible implementation, Figure 3This is a schematic diagram of another insulation detection circuit provided in Embodiment 1 of this application, as shown below. Figure 3 As shown, the second voltage divider module 23 includes: a first resistor R1, a second resistor R2, and a first switch K1;

[0054] One end of the first resistor R1 is connected to the negative terminal of the battery, and the other end of the first resistor R1 is connected to one end of the second resistor R2. The connection point of the first resistor R1 and the second resistor R2 is used as the first sampling point and connected to the sampling module 20.

[0055] The other end of the second resistor R2 is connected to one end of the first switch K1; the other end of the first switch K1 is grounded.

[0056] Based on the above example, the third voltage divider module is located on the first path, the first sampling point is located on the first path, and during the insulation detection process, the first path is in a conductive state. Therefore, during the insulation detection process, the first switch K1 is in a closed state.

[0057] Specifically, in the first stage, the first switch K1 is closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the first voltage U1. In the second stage, the first switch K1 remains closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the second path is open, and the second path is equivalently connected in parallel to the equivalent resistance Rp1 between the positive terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the second voltage U2. Based on the first voltage U1 and the second voltage U2 acquired by module 20, the detection module 21 can determine the equivalent resistance Rp1 between the positive terminal of the battery and the ground, and the equivalent resistance Rn1 between the negative terminal of the battery and the ground. Thus, the detection module 21 can perform insulation detection on the battery terminal.

[0058] Based on this, in the third stage, the first switch K1 remains closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the third path is open, and the third path is connected in series with the equivalent resistance Rp2 between the positive terminal of the load and ground, and is connected in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 acquires the voltage at the first sampling point to obtain the third voltage U3. In the fourth stage, the first switch K1 remains closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the fourth path is open, and the fourth path is connected in series with the equivalent resistance Rn2 between the negative terminal of the load and ground, and is connected in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 acquires the voltage at the first sampling point to obtain the fourth voltage U4. Based on the third voltage U3 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rp2 between the positive terminal of the load and ground. Similarly, based on the fourth voltage U4 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rn2 between the negative terminal of the load and ground. Therefore, the detection module 21 can perform insulation detection on the load.

[0059] It is understood that the second voltage divider module 23 includes a first resistor R1, a second resistor R2, and a first switch K1. The first switch K1 can control whether the first path is conducting. The first resistor R1 and the second resistor R2 divide the voltage on the first path. The connection point of the first resistor R1 and the second resistor R2 is used as the first sampling point, which facilitates the sampling module 20 to collect voltage under different states. Then, the detection module 21 can realize the insulation detection of the battery terminal and the load terminal based on the voltage obtained by the sampling module 20.

[0060] In this embodiment, the second voltage divider module includes a first resistor, a second resistor, and a first switch. The connection point of the first and second resistors is used as the first sampling point. When the first path is conducting, the first resistor, the second resistor, and the first switch are connected in series and in parallel with the equivalent resistance between the negative terminal of the battery and ground. When the second path is conducting, the second path is connected in parallel with the equivalent resistance between the positive terminal of the battery and ground. The acquisition module acquires the voltage at the first sampling point when the first path is conducting, and when the first and second paths are conducting, respectively. Based on the voltage acquired by the sampling module, the detection module can determine the equivalent resistance between the positive terminal of the battery and ground, and the equivalent resistance between the negative terminal of the battery and ground, and can perform insulation detection on the battery terminal. The third and fourth voltage divider modules can connect the equivalent resistance between the positive terminal of the load and ground, and the equivalent resistance between the negative terminal of the load and ground, to the battery terminal. The sampling module acquires the voltage at the first sampling point, and the detection module can perform insulation detection on the load terminal based on the voltage acquired by the sampling module. Therefore, the solution of this application can still achieve insulation detection of the load end when the load end and the battery end are not connected, thus improving the accuracy of insulation detection.

[0061] Optionally, in one possible implementation, Figure 4 This is a schematic diagram of another insulation detection circuit provided in Embodiment 1 of this application, as shown below. Figure 4 As shown, the first voltage divider module 22 includes: a third resistor R3 and a second switch K2;

[0062] One end of the third resistor R3 is connected to the positive terminal of the battery, and the other end of the third resistor R3 is connected to one end of the second switch K2.

[0063] The other end of the second switch K2 is connected to the other end of the first switch K1 and grounded.

[0064] The second switch K2 is used to control the conduction or disconnection state of the second path. In the second stage, the second switch K2 is in the closed state and the second path is conducted. In other stages, the second switch K2 is in the open state.

[0065] Specifically, in the first stage, the first switch K1 is closed, the second switch K2 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the first voltage U1. In the second stage, the first switch K1 remains closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the second switch K2 is closed, the second path is open, and the third resistor R3 is connected in series with the second switch K2 and is equivalently connected in parallel to the equivalent resistance Rp1 between the positive terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the second voltage U2. Based on the first voltage U1 and the second voltage U2 acquired by module 20, the detection module 21 can determine the equivalent resistance Rp1 between the positive terminal of the battery and the ground, and the equivalent resistance Rn1 between the negative terminal of the battery and the ground. Thus, the detection module 21 can perform insulation detection on the battery terminal.

[0066] Based on this, in the third stage, the first switch K1 remains closed, the second switch K2 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the third path is open, and the third path is connected in series with the equivalent resistance Rp2 between the positive terminal of the load and ground, and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the third voltage U3. In the fourth stage, the first switch K1 remains closed, the second switch K2 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the fourth path is activated, and the fourth path is connected in series with the equivalent resistance Rn2 between the negative terminal of the load and ground, and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 acquires the voltage at the first sampling point to obtain the fourth voltage U4. Based on the third voltage U3 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rp2 between the positive terminal of the load and ground. Similarly, based on the fourth voltage U4 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rn2 between the negative terminal of the load and ground. Therefore, the detection module 21 can perform insulation detection on the load.

[0067] In this embodiment, the second voltage divider module includes a first resistor, a second resistor, and a first switch. The connection point of the first and second resistors is used as the first sampling point. When the first path is conducting, the first resistor, the second resistor, and the first switch are connected in series and in parallel with the equivalent resistance between the negative terminal of the battery and ground. The first voltage divider module includes a third resistor and a second switch. When the second path is conducting, the third resistor and the second switch are connected in series and in parallel with the equivalent resistance between the positive terminal of the battery and ground. The acquisition module acquires the voltage at the first sampling point when the first path is conducting, and when both the first and second paths are conducting. Based on the voltage acquired by the sampling module, the detection module can determine the equivalent resistance between the positive terminal of the battery and ground, and the equivalent resistance between the negative terminal of the battery and ground, enabling insulation detection of the battery terminal. Through the third and fourth voltage divider modules, the equivalent resistance between the positive terminal of the load and ground and the equivalent resistance between the negative terminal of the load and ground can be connected to the battery terminal. The sampling module acquires the voltage at the first sampling point, and the detection module can perform insulation detection of the load terminal based on the voltage acquired by the sampling module. Therefore, the solution of this application can still achieve insulation detection of the load end when the load end and the battery end are not connected, thus improving the accuracy of insulation detection.

[0068] Optionally, in one possible implementation, Figure 5 This is a schematic diagram of another insulation detection circuit provided in Embodiment 1 of this application, as shown below. Figure 5 As shown, the third voltage divider module 24 includes: a fourth resistor R4, a fifth resistor R5, and a third switch K3;

[0069] One end of the fourth resistor R4 is connected to the positive terminal of the load, and the other end of the fourth resistor R4 is connected to one end of the third switch K3.

[0070] The other end of the third switch K3 is connected to one end of the fifth resistor R5, and the connection point between the third switch K3 and the fifth resistor R5 is used as the second sampling point and connected to the sampling module 20.

[0071] The other end of the fifth resistor R5 is connected to the negative terminal of the battery.

[0072] The third switch K3 is used to control the conduction or disconnection state of the third path. In the third stage, the third switch K3 is in the closed state and the third path is conducted. In other stages, the third switch K3 is in the open state.

[0073] Specifically, in the first stage, the first switch K1 is closed, the third switch K3 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the first voltage U1. In the second stage, the first switch K1 remains closed, the third switch K3 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the second path is open and is equivalently connected in parallel to the equivalent resistance Rp1 between the positive terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the second voltage U2. Based on the first voltage U1 and the second voltage U2 acquired by module 20, the detection module 21 can determine the equivalent resistance Rp1 between the positive terminal of the battery and the ground, and the equivalent resistance Rn1 between the negative terminal of the battery and the ground. Thus, the detection module 21 can perform insulation detection on the battery terminal.

[0074] Based on this, in the third stage, the first switch K1 remains closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the third switch K3 is closed, the third path is open, and the fourth resistor R4, the fifth resistor R5, the third switch K3, and the equivalent resistance Rp2 between the positive terminal of the load and ground are connected in series and are connected in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the third voltage U3. In the fourth stage, the first switch K1 remains closed, the third switch K3 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the fourth path is activated, and the fourth path is connected in series with the equivalent resistance Rn2 between the negative terminal of the load and ground, and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 acquires the voltage at the first sampling point to obtain the fourth voltage U4. Based on the third voltage U3 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rp2 between the positive terminal of the load and ground. Similarly, based on the fourth voltage U4 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rn2 between the negative terminal of the load and ground. Therefore, the detection module 21 can perform insulation detection on the load.

[0075] In this embodiment, the second voltage divider module includes a first resistor, a second resistor, and a first switch. The connection point of the first and second resistors is used as the first sampling point. When the first path is conducting, the first resistor, the second resistor, and the first switch are connected in series and in parallel with the equivalent resistance between the negative terminal of the battery and ground. When the second path is conducting, the second path is connected in parallel with the equivalent resistance between the positive terminal of the battery and ground. The acquisition module acquires the voltage at the first sampling point when the first path is conducting, and when the first and second paths are conducting, respectively. Based on the voltage acquired by the sampling module, the detection module can determine the equivalent resistance between the positive terminal of the battery and ground and the equivalent resistance between the negative terminal of the battery and ground, and can perform insulation detection on the battery terminal. The third voltage divider module includes a fourth resistor, a fifth resistor, and a third switch. Through the third and fourth voltage divider modules, the equivalent resistance between the positive terminal of the load and ground and the equivalent resistance between the negative terminal of the load and ground can be connected to the battery terminal. The sampling module acquires the voltage at the first sampling point, and the detection module can perform insulation detection on the load terminal based on the voltage acquired by the sampling module. Therefore, the solution of this application can still achieve insulation detection of the load end when the load end and the battery end are not connected, thus improving the accuracy of insulation detection.

[0076] Optionally, in one possible implementation, Figure 6 This is a schematic diagram of another insulation detection circuit provided in Embodiment 1 of this application, as shown below. Figure 6 As shown, the fourth voltage divider module 25 includes: a sixth resistor R6, a seventh resistor R7, and a fourth switch K4;

[0077] One end of the sixth resistor R6 is connected to the negative terminal of the load, and the other end of the sixth resistor R6 is connected to one end of the fourth switch K4.

[0078] The other end of the fourth switch K4 is connected to one end of the seventh resistor R7, and the connection between the fourth switch K4 and the seventh resistor R7 is used as the third sampling point and connected to the sampling module 20.

[0079] The other end of the seventh resistor R7 is connected to the negative terminal of the battery.

[0080] The fourth switch K4 is used to control the conduction or disconnection state of the fourth path. In the fourth stage, the fourth switch K4 is in the closed state and the fourth path is conducted. In other stages, the fourth switch K4 is in the open state.

[0081] Specifically, in the first stage, the first switch K1 is closed, the fourth switch K4 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the first voltage U1. In the second stage, the first switch K1 remains closed, the fourth switch K4 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the second path is open and is equivalently connected in parallel to the equivalent resistance Rp1 between the positive terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the second voltage U2. Based on the first voltage U1 and the second voltage U2 acquired by module 20, the detection module 21 can determine the equivalent resistance Rp1 between the positive terminal of the battery and the ground, and the equivalent resistance Rn1 between the negative terminal of the battery and the ground. Thus, the detection module 21 can perform insulation detection on the battery terminal.

[0082] Based on this, in the third stage, the first switch K1 remains closed, the fourth switch K4 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the third path is open, and the third path and the equivalent resistance Rp2 between the positive terminal of the load and ground are connected in series and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the third voltage U3. In the fourth stage, the first switch K1 remains closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, with the fourth switch K4 in the ON state, the fourth path is open. The sixth resistor R6, the seventh resistor R7, the fourth switch K4, and the equivalent resistance Rn2 between the negative terminal of the load and ground are connected in series, and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 acquires the voltage at the first sampling point to obtain the fourth voltage U4. Based on the third voltage U3 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rp2 between the positive terminal of the load and ground. Similarly, based on the fourth voltage U4 acquired by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the detection module 21 can determine the resistance value of the equivalent resistance Rn2 between the negative terminal of the load and ground. Therefore, the detection module 21 can perform insulation detection on the load.

[0083] In this embodiment, the second voltage divider module includes a first resistor, a second resistor, and a first switch. The connection point of the first and second resistors is used as the first sampling point. When the first path is conducting, the first resistor, the second resistor, and the first switch are connected in series and in parallel with the equivalent resistance between the negative terminal of the battery and ground. When the second path is conducting, the second path is connected in parallel with the equivalent resistance between the positive terminal of the battery and ground. The acquisition module acquires the voltage at the first sampling point when the first path is conducting, and when the first and second paths are conducting, respectively. Based on the voltage acquired by the sampling module, the detection module can determine the equivalent resistance between the positive terminal of the battery and ground and the equivalent resistance between the negative terminal of the battery and ground, and can perform insulation detection on the battery terminal. The fourth voltage divider module includes a sixth resistor, a seventh resistor, and a fourth switch. Through the third and fourth voltage divider modules, the equivalent resistance between the positive terminal of the load and ground and the equivalent resistance between the negative terminal of the load and ground can be connected to the battery terminal. The sampling module acquires the voltage at the first sampling point, and the detection module can perform insulation detection on the load terminal based on the voltage acquired by the sampling module. Therefore, the solution of this application can still achieve insulation detection of the load end when the load end and the battery end are not connected, thus improving the accuracy of insulation detection.

[0084] Optionally, in one possible implementation, the insulation detection circuit further includes: a first capacitor, a fifth switch, a sixth switch, a seventh switch, and an eighth resistor;

[0085] One end of the first capacitor is connected to the positive terminal of the load, and the other end of the first capacitor is connected to the negative terminal of the load.

[0086] The fifth switch is connected in series on the transmission path between the positive terminal of the battery and the positive terminal of the load.

[0087] One end of the sixth switch is connected to the positive terminal of the battery, and the other end of the sixth switch is connected to one end of the eighth resistor; the other end of the eighth resistor is connected to the positive terminal of the load.

[0088] The seventh switch is connected in series on the transmission path between the negative terminal of the battery and the negative terminal of the load.

[0089] The fifth switch controls whether the load is connected to the battery. In practice, it controls whether the battery supplies power to the load. For example, the battery operates in two phases: charging and discharging. During the charging phase, the battery does not supply power to the load, and the fifth switch is open. During the discharging phase, the battery supplies power to the load, and the fifth switch is closed.

[0090] Among them, the first capacitor is a capacitor used to suppress electromagnetic interference of the power supply, such as capacitor X1, capacitor X2, capacitor X3, etc., which is used for power supply filtering to avoid differential mode interference affecting the voltage output of the battery to the load.

[0091] In this circuit, the sixth switch is connected in series with the eighth resistor and in parallel with the fifth switch. In practical applications, during the battery discharge phase, the fifth switch is first opened, while the seventh and sixth switches are closed. The eighth resistor, acting as a current-limiting resistor, effectively protects the circuit and prevents excessive current from affecting it. It also charges the first capacitor until the voltage across it stabilizes. Then, the sixth switch is opened, the fifth switch is closed, and the battery supplies power to the load normally.

[0092] In this embodiment, a fifth switch, a sixth switch, a seventh switch, and an eighth resistor are installed on the transmission path between the battery end and the load end, which can protect the circuit and improve the reliability of the circuit.

[0093] In practical applications, the implementation of the above-mentioned switch is not limited here. Optionally, in one possible implementation, at least one switch in the above-mentioned insulation detection circuit is an electrical isolation switch, which includes an optocoupler and a photoelectric MOSFET.

[0094] Optionally, in one possible implementation, at least one switch in the above-mentioned insulation detection circuit is a controllable switch, which includes a small-signal relay and a reed relay. In practice, the controllable switch can be controlled to close or open by sending an electrical signal to it.

[0095] In the insulation detection circuit provided in this embodiment, a first voltage divider module, a second voltage divider module, a third voltage divider module, and a fourth voltage divider module are respectively set between the positive terminal of the battery and ground, between the negative terminal of the battery and ground, between the positive terminal of the load and the negative terminal of the battery, and between the negative terminal of the load and the negative terminal of the battery. A sampling module, connected to the first, second, third, and fourth voltage divider modules, collects the voltage at the first sampling point location under different states. These different states include: the first path from the negative terminal of the battery through the second voltage divider module to ground is in a conductive state; the first path and the second path from the positive terminal of the battery through the first voltage divider module to ground are in a conductive state; the first path and the third path from the positive terminal of the load through the third voltage divider module to the negative terminal of the battery are in a conductive state; and the first path and the fourth path from the negative terminal of the load through the fourth voltage divider module to the negative terminal of the battery are in a conductive state. A detection module is connected to the sampling module and is used to perform insulation detection on the battery terminal and / or the load terminal based on the voltage collected by the sampling module. In this embodiment, when the first path is conducting, it is connected in parallel with the equivalent resistance between the negative terminal of the battery and ground. When the second path is conducting, it is connected in parallel with the equivalent resistance between the positive terminal of the battery and ground. The acquisition module acquires the voltage at the first sampling point when the first path, the first path, and the second path are conducting, respectively. Based on the voltage acquired by the sampling module, the detection module can determine the equivalent resistance between the positive terminal of the battery and ground, and the negative terminal of the battery and ground, thus enabling insulation detection of the battery. The third and fourth voltage divider modules connect the equivalent resistance between the positive terminal of the load and ground, and the equivalent resistance between the negative terminal of the load and ground, to the battery. The sampling module acquires the voltage at the first sampling point, and the detection module can perform insulation detection of the load based on the voltage acquired by the sampling module. Therefore, the solution of this application can still achieve insulation detection of the load when the load and battery are not connected, improving the accuracy of insulation detection.

[0096] Example 2

[0097] Figure 7 This is a schematic diagram of an insulation detection circuit provided in Embodiment 2 of this application, as shown below. Figure 7 As shown, the insulation detection circuit includes: sampling module 20, detection module 21, first voltage divider module 22, second voltage divider module 23, third voltage divider module 24, fourth voltage divider module 25, first capacitor C1, fifth switch K5, sixth switch K6, seventh switch K7, and eighth resistor R8.

[0098] The first voltage divider module 22 includes a third resistor R3 and a second switch K2; the second voltage divider module 23 includes a first resistor R1, a second resistor R2 and a first switch K1; the third voltage divider module 24 includes a fourth resistor R4, a fifth resistor R5 and a third switch K3; and the fourth voltage divider module 25 includes a sixth resistor R6, a seventh resistor R7 and a fourth switch K4.

[0099] Specifically, in the first stage, the first switch K1 is closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the first voltage U1. In the second stage, the first switch K1 remains closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the second switch K2 is closed, the second path is open, and the third resistor R3 is connected in series with the second switch K2 and is equivalently connected in parallel to the equivalent resistance Rp1 between the positive terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the second voltage U2.

[0100] Based on the first voltage U1 and the second voltage U2 acquired by module 20, the detection module 21 can determine the equivalent resistance Rp1 between the positive terminal of the battery and the ground, and the equivalent resistance Rn1 between the negative terminal of the battery and the ground. Thus, the detection module 21 can perform insulation detection on the battery terminal.

[0101] Specifically, given the total battery voltage as U0, we establish the first equation corresponding to the first voltage U1 and the second equation corresponding to the second voltage U2 based on Kirchhoff's laws. The expression for the first equation is as follows:

[0102]

[0103] The expression for the second equation is as follows:

[0104]

[0105] Based on the first and second equations, a system of equations is established, and the equivalent resistance Rp1 of the positive terminal and the equivalent resistance Rn1 of the negative terminal of the battery are calculated:

[0106]

[0107] Rn1=-(R2*R4^2*U0*U1-R2*R4^2*U0*U2+R2*R3*R4*U0*U1-R2

[0108] *R3*R4*U0*U2) / (R4^2*U0^2-R4^2*U0*U1+R3^2*U1*U2

[0109] -R4^2*U0*U2+R4^2*U1*U2+R2*R4*U0*U1-R2*R4*U0

[0110] *U2-R3*R4*U0*U1-R3*R4*U0*U2+2*R3*R4*U1*U2)

[0111] Based on this, in the third stage, the first switch K1 remains closed, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Furthermore, the third switch K3 is closed, the third path is open, and the fourth resistor R4, the fifth resistor R5, the third switch K3, and the equivalent resistance Rp2 between the positive terminal of the load and ground are connected in series and are connected in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 collects the voltage at the first sampling point to obtain the third voltage U3.

[0112] Based on the third voltage U3 obtained by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, detection module 21 can determine the value of the equivalent resistance Rp2 between the positive terminal of the load and ground. Specifically, a third equation corresponding to the third voltage is established according to Kirchhoff's laws. The expression of the third equation is as follows:

[0113]

[0114] Solve the third-party program to obtain the equivalent resistance Rp2 of the positive terminal of the load:

[0115] Rp2=((R3+R4)*(R5+R6)+Rn1(R3+R4)+Rn1(R5+R6)-(R4*Rn1*(R5+R6)*[U0

[0116] -(U3(R3+R4)) / R4]) / (Rp1*U3)) / (R3+R4+Rn1-(R4*Rn1*[U0-(U3

[0117] *(R3+R4)) / R4]) / (Rp1*U3))

[0118] In the fourth stage, the first switch K1 remains closed, the third switch K3 is open, the first path is open, and the first resistor R1, the second resistor R2, and the first switch K1 are connected in series and are equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground. Meanwhile, the fourth switch K4 is open, the fourth path is open, and the sixth resistor R6, the seventh resistor R7, the fourth switch K4, and the equivalent resistance Rn2 between the negative terminal of the load and ground are connected in series and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground. The sampling module 20 acquires the voltage at the first sampling point to obtain the fourth voltage U4.

[0119] Based on the fourth voltage U4 obtained by module 20, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, detection module 21 can determine the value of the equivalent resistance Rn2 between the negative terminal of the load and ground; therefore, detection module 21 can perform insulation detection on the load terminal. Specifically, a fourth equation corresponding to the fourth voltage is established according to Kirchhoff's laws, and the expression of the fourth equation is as follows:

[0120]

[0121] Solving the fourth equation yields the equivalent resistance Rn2 at the positive terminal of the load:

[0122] Rn2=((R3+R4)*(R7+R8)+Rn1(R3+R4)+Rn1(R7+R8)-(R4*Rn1*(R7+R8)*[U0

[0123] -(U3(R3+R4)) / R4]) / (Rp1*U4)) / (R3+R4+Rn1-(R4*Rn1*[U0-(U4

[0124] *(R3+R4)) / R4]) / (Rp1*U4))

[0125] Therefore, insulation detection is performed on the battery terminal and / or the load terminal based on the equivalent resistance Rp1 of the positive terminal of the battery terminal, the equivalent resistance Rn1 of the negative terminal of the battery terminal, the equivalent resistance Rp2 of the positive terminal of the load terminal, and the equivalent resistance Rn2 of the positive terminal of the load terminal.

[0126] In the insulation detection circuit provided in this embodiment, a first voltage divider module, a second voltage divider module, a third voltage divider module, and a fourth voltage divider module are respectively set between the positive terminal of the battery and ground, between the negative terminal of the battery and ground, between the positive terminal of the load and the negative terminal of the battery, and between the negative terminal of the load and the negative terminal of the battery. A sampling module, connected to the first, second, third, and fourth voltage divider modules, collects the voltage at the first sampling point location under different states. These different states include: the first path from the negative terminal of the battery through the second voltage divider module to ground is in a conductive state; the first path and the second path from the positive terminal of the battery through the first voltage divider module to ground are in a conductive state; the first path and the third path from the positive terminal of the load through the third voltage divider module to the negative terminal of the battery are in a conductive state; and the first path and the fourth path from the negative terminal of the load through the fourth voltage divider module to the negative terminal of the battery are in a conductive state. A detection module is connected to the sampling module and is used to perform insulation detection on the battery terminal and / or the load terminal based on the voltage collected by the sampling module. In this embodiment, when the first path is conducting, it is connected in parallel with the equivalent resistance between the negative terminal of the battery and ground. When the second path is conducting, it is connected in parallel with the equivalent resistance between the positive terminal of the battery and ground. The acquisition module acquires the voltage at the first sampling point when the first path, the first path, and the second path are conducting, respectively. Based on the voltage acquired by the sampling module, the detection module can determine the equivalent resistance between the positive terminal of the battery and ground, and the equivalent resistance between the negative terminal of the battery and ground, enabling insulation detection of the battery terminal. The third and fourth voltage divider modules connect the equivalent resistance between the positive terminal of the load and ground, and the equivalent resistance between the negative terminal of the load and ground, to the battery terminal. The sampling module acquires the voltage at the first sampling point, and the detection module can perform insulation detection of the load terminal based on the voltage acquired by the sampling module. Therefore, the solution of this application can still achieve insulation detection of the load terminal when the load terminal and the battery terminal are not connected, improving the accuracy of insulation detection.

[0127] Example 3

[0128] Figure 8 This is a flowchart illustrating an insulation detection method provided in Embodiment 2 of this application. Based on the insulation detection circuit in the above embodiments, as follows... Figure 8 As shown, the method includes the following steps:

[0129] Step 801: Control the first path to conduct, and obtain the first voltage sampled by the sampling module at the first sampling point position;

[0130] Step 802: Control the first path and the second path to conduct, and obtain the second voltage sampled by the sampling module at the first sampling point position;

[0131] Step 803: Control the first path and the third path to conduct, and obtain the third voltage sampled by the sampling module at the first sampling point position;

[0132] Step 804: Control the first path and the fourth path to conduct, and obtain the fourth voltage sampled by the sampling module at the first sampling point position;

[0133] Step 805: Perform insulation testing on the battery terminals and / or load terminals based on the first voltage, the second voltage, the third voltage, and the fourth voltage.

[0134] In practical applications, the insulation detection method provided in this embodiment can be applied to new energy vehicles, including but not limited to pure electric vehicles and hybrid electric vehicles. In this embodiment, grounding refers to the reference grounding of the new energy vehicle body. The insulation detection circuit essentially detects the insulation status between the positive terminal of the battery and the vehicle body, the negative terminal of the battery and the vehicle body, the positive terminal of the load and the vehicle body, and the negative terminal of the load and the vehicle body.

[0135] In one example, the equivalent resistance values ​​of the battery terminal between the positive terminal and ground (Rp1), the battery terminal between the negative terminal and ground (Rn1), the load terminal between the positive terminal and ground (Rp2), and the load terminal between the negative terminal and ground (Rn2) can be detected. These four equivalent resistance values ​​can be compared with preset resistance thresholds. If any of these four equivalent resistance values ​​is greater than the preset threshold, it indicates that the insulation protection of the vehicle body is abnormal. The user can be notified through an alarm, ensuring the user's personal safety and improving the safety and reliability of the vehicle.

[0136] In this embodiment, the insulation detection process is divided into four stages. Specifically, in the first stage, the first path is controlled to conduct, and the first voltage U1 sampled by the sampling module at the first sampling point is obtained; in the second stage, the first path and the second path are controlled to conduct, and the second voltage U2 sampled by the sampling module at the first sampling point is obtained; in the third stage, the first path and the third path are controlled to conduct, and the third voltage U3 sampled by the sampling module at the first sampling point is obtained; in the fourth stage, the first path and the fourth path are controlled to conduct, and the fourth voltage U4 sampled by the sampling module at the first sampling point is obtained.

[0137] Specifically, the first sampling point is located on the first path, and the first path is in a conductive state during the insulation detection process. In the first stage, the first path is controlled to conduct, and the first path is equivalently connected in parallel to the equivalent resistance Rn1 between the negative terminal of the battery and ground, obtaining the first voltage U1 sampled by the sampling module at the first sampling point. In the second stage, the first path and the second path are controlled to conduct, and the second path is equivalently connected in parallel to the equivalent resistance Rp1 between the positive terminal of the battery and ground, obtaining the second voltage U2 sampled by the sampling module at the first sampling point. Based on the first voltage U1 and the second voltage U2, the resistance values ​​of the equivalent resistance Rp1 between the positive terminal of the battery and ground and the equivalent resistance Rn1 between the negative terminal of the battery and ground are determined, thereby enabling insulation detection of the battery terminal.

[0138] Based on this, in the third stage, the first path and the third path are both turned on. The third path is connected in series with the equivalent resistance Rp2 between the positive terminal of the load and ground, and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground, to obtain the third voltage U3 sampled by the sampling module at the first sampling point. In the fourth stage, the first path and the fourth path are both turned on. The fourth path is connected in series with the equivalent resistance Rn2 between the negative terminal of the load and ground, and in parallel with the equivalent resistance Rn1 between the negative terminal of the battery and ground, to obtain the fourth voltage U4 sampled by the sampling module at the first sampling point. Based on the third voltage U3, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the resistance value of the equivalent resistance Rp2 between the positive terminal of the load and ground is determined; similarly, based on the fourth voltage U4, the equivalent resistance Rp1 between the positive terminal of the battery and ground, and the equivalent resistance Rn1 between the negative terminal of the battery and ground, the resistance value of the equivalent resistance Rn2 between the negative terminal of the load and ground is determined; thus, insulation detection of the load terminal can be achieved.

[0139] It is understood that in this embodiment, by controlling the conduction of different paths, the first, second, third, and fourth voltages acquired by the acquisition module are obtained. This allows for the determination of the equivalent resistance Rp1 between the positive terminal of the battery and ground, the equivalent resistance Rn1 between the negative terminal of the battery and ground, the equivalent resistance Rp2 between the positive terminal of the load and ground, and the equivalent resistance Rn2 between the negative terminal of the load and ground. Detection of these four equivalent resistances enables insulation detection between the battery and load terminals. Furthermore, the insulation detection method in this embodiment can perform insulation detection on the load terminal regardless of whether the battery and load terminals are connected, thus improving the accuracy of insulation detection.

[0140] Optionally, in one possible implementation, step 805 above includes:

[0141] Based on Kirchhoff's laws, establish the first equation corresponding to the first voltage and the second equation corresponding to the second voltage.

[0142] Based on the first and second equations, a system of equations is established to calculate the equivalent resistance of the positive terminal and the equivalent resistance of the negative terminal of the battery.

[0143] Establish a third solution corresponding to the third voltage based on Kirchhoff's laws, and solve the third solution to obtain the equivalent resistance of the positive terminal of the load.

[0144] Based on Kirchhoff's laws, establish the fourth equation corresponding to the fourth voltage, and solve the fourth equation to obtain the equivalent resistance of the positive terminal of the load.

[0145] Insulation testing is performed on the battery terminals and / or load terminals based on the equivalent resistance of the positive terminal of the battery terminal, the equivalent resistance of the negative terminal of the battery terminal, the equivalent resistance of the positive terminal of the load terminal, and the equivalent resistance of the positive terminal of the load terminal.

[0146] Specifically, given the total battery voltage as U0, we establish the first equation corresponding to the first voltage U1 and the second equation corresponding to the second voltage U2 based on Kirchhoff's laws. The expression for the first equation is as follows:

[0147]

[0148] The expression for the second equation is as follows:

[0149]

[0150] Based on the first and second equations, a system of equations is established, and the equivalent resistance Rp1 of the positive terminal and the equivalent resistance Rn1 of the negative terminal of the battery are calculated:

[0151]

[0152] Rn1=-(R2*R4^2*U0*U1-R2*R4^2*U0*U2+R2*R3*R4*U0*U1-R2

[0153] *R3*R4*U0*U2) / (R4^2*U0^2-R4^2*U0*U1+R3^2*U1*U2

[0154] -R4^2*U0*U2+R4^2*U1*U2+R2*R4*U0*U1-R2*R4*U0

[0155] *U2-R3*R4*U0*U1-R3*R4*U0*U2+2*R3*R4*U1*U2)

[0156] Based on this, a third equation corresponding to the third voltage is established according to Kirchhoff's laws. The expression of the third equation is as follows:

[0157]

[0158] Solve the third-party program to obtain the equivalent resistance Rp2 of the positive terminal of the load:

[0159] Rp2=((R3+R4)*(R5+R6)+Rn1(R3+R4)+Rn1(R5+R6)-(R4*Rn1*(R5+R6)*[U0

[0160] -(U3(R3+R4)) / R4]) / (Rp1*U3)) / (R3+R4+Rn1-(R4*Rn1*[U0-(U3

[0161] *(R3+R4)) / R4]) / (Rp1*U3))

[0162] Based on Kirchhoff's laws, the fourth equation corresponding to the fourth voltage is established, and the expression of the fourth equation is as follows:

[0163]

[0164] Solving the fourth equation yields the equivalent resistance Rn2 at the positive terminal of the load:

[0165] Rn2=((R3+R4)*(R7+R8)+Rn1(R3+R4)+Rn1(R7+R8)-(R4*Rn1*(R7+R8)*[U0

[0166] -(U3(R3+R4)) / R4]) / (Rp1*U4)) / (R3+R4+Rn1-(R4*Rn1*[U0-(U4

[0167] *(R3+R4)) / R4]) / (Rp1*U4))

[0168] The equivalent resistance values ​​of the positive terminal of the battery, Rp1, the negative terminal of the battery, Rp2, and Rn2 of the positive terminal of the load are compared with preset resistance thresholds. If any of these four equivalent resistance values ​​is greater than the preset value, it indicates that the insulation protection of the vehicle body is abnormal. The user can be notified through an alarm to ensure the user's personal safety and improve the safety and reliability of the vehicle.

[0169] In this embodiment, based on the first voltage, second voltage, third voltage, and fourth voltage, the equivalent resistance Rp1 between the positive terminal of the battery and ground, the equivalent resistance Rn1 between the negative terminal of the battery and ground, the equivalent resistance Rp2 between the positive terminal of the load and ground, and the equivalent resistance Rn2 between the negative terminal of the load and ground are calculated. Insulation detection of the battery and load terminals can be achieved by detecting these four equivalent resistances. Furthermore, the insulation detection method in this embodiment can perform insulation detection of the load terminal regardless of whether the battery and load terminals are connected, thus improving the accuracy of insulation detection.

[0170] Optionally, in one possible implementation, prior to step 805 above, the method further includes:

[0171] Determine whether the fifth and seventh switches are conducting; if not, proceed to step 805.

[0172] If conduction is achieved, the method further includes:

[0173] Insulation tests are performed on the battery terminals and / or load terminals based on the first voltage and the second voltage.

[0174] In practical applications, when the fifth and seventh switches are on, step 805 is executed, as detailed in the example above, and will not be repeated here. When the fifth and seventh switches are on, the load terminal is connected to the battery terminal. To simplify the insulation detection process, insulation detection can be performed on the battery terminal and / or load terminal based on the first and second voltages when the fifth and seventh switches are on.

[0175] In this embodiment, the method of determining whether the fifth and seventh switches are conducting is dynamically selected to detect the insulation at the load end, which improves the efficiency of insulation detection. Furthermore, insulation detection at the load end can be performed regardless of whether the battery end and the load end are connected, thus improving the accuracy of insulation detection.

[0176] Optionally, regarding the method for determining whether the fifth and seventh switches are conducting, in one possible implementation, the determination of whether the fifth and seventh switches are conducting includes:

[0177] The third path is controlled to be turned on, and the fifth voltage sampled by the sampling module at the second sampling point is obtained.

[0178] Control the fourth path to conduct, and obtain the sixth voltage sampled by the sampling module at the third sampling point;

[0179] Based on the fifth and sixth voltages, calculate the voltage between the positive and negative terminals of the load.

[0180] Determine if the voltage between the positive and negative terminals of the load is 0. If it is not 0, determine that the fifth and seventh switches are on; if it is 0, determine that the fifth and seventh switches are off.

[0181] Referring to the above example, the second sampling point is the connection point between the third switch and the fifth resistor, and the third sampling point is the connection point between the fourth switch and the seventh resistor. In this embodiment, the third path is controlled to conduct, obtaining the fifth voltage sampled by the sampling module at the second sampling point; the fourth path is controlled to conduct, obtaining the sixth voltage sampled by the sampling module at the third sampling point; the voltage between the positive and negative terminals of the load is calculated based on the fifth and sixth voltages; by determining whether the voltage between the positive and negative terminals of the load is 0, it is determined whether the fifth and seventh switches are conducting, thereby enabling the appropriate selection of the load-side insulation detection method.

[0182] In the insulation detection method provided in this embodiment, firstly, the first path is controlled to conduct, obtaining the first voltage sampled by the sampling module at the first sampling point; then, the first and second paths are controlled to conduct, obtaining the second voltage sampled by the sampling module at the first sampling point; then, the first and third paths are controlled to conduct, obtaining the third voltage sampled by the sampling module at the first sampling point; then, the first and fourth paths are controlled to conduct, obtaining the fourth voltage sampled by the sampling module at the first sampling point; finally, insulation detection is performed on the battery terminal and / or load terminal based on the first, second, third, and fourth voltages. In the above scheme, by controlling the conduction of different paths to obtain the first, second, third, and fourth voltages collected by the acquisition module, the equivalent resistance between the positive terminal of the battery terminal and ground, the equivalent resistance between the negative terminal of the battery terminal and ground, the equivalent resistance between the positive terminal of the load terminal and ground, and the equivalent resistance between the negative terminal of the load terminal and ground can be determined. Insulation detection of the battery terminal and load terminal can be achieved by detecting these four equivalent resistances. Furthermore, the insulation detection method in this embodiment can perform insulation detection on the load end regardless of whether the battery end and the load end are connected, thus improving the accuracy of insulation detection.

[0183] Example 3

[0184] This application provides a third embodiment of an automobile, including an insulation detection circuit as described in the foregoing embodiments.

[0185] For example, the insulation detection circuit is integrated into the car. When insulation testing of the car is required, the insulation status between the car body and the positive terminal of the battery, between the car body and the negative terminal of the battery, between the car body and the positive terminal of the load, and between the car body and the negative terminal of the load can be detected by the insulation detection circuit in this embodiment.

[0186] In the vehicle provided in this embodiment, a first voltage divider module, a second voltage divider module, a third voltage divider module, and a fourth voltage divider module are respectively installed between the positive terminal of the battery and ground, between the negative terminal of the battery and ground, between the positive terminal of the load and the negative terminal of the battery, and between the negative terminal of the load and the negative terminal of the battery. A sampling module is connected to the first, second, third, and fourth voltage divider modules to collect the voltage at the first sampling point location under different states. These different states include: a first path from the negative terminal of the battery through the second voltage divider module to ground is in a conductive state; a second path from the first path and the positive terminal of the battery through the first voltage divider module to ground is in a conductive state; a third path from the first path and the positive terminal of the load through the third voltage divider module to the negative terminal of the battery is in a conductive state; and a fourth path from the first path and the negative terminal of the load through the fourth voltage divider module to the negative terminal of the battery is in a conductive state. A detection module is connected to the sampling module and is used to perform insulation detection on the battery terminal and / or the load terminal based on the voltage collected by the sampling module. In this embodiment, when the first path is conducting, it is connected in parallel with the equivalent resistance between the negative terminal of the battery and ground. When the second path is conducting, it is connected in parallel with the equivalent resistance between the positive terminal of the battery and ground. The acquisition module acquires the voltage at the first sampling point when the first path, the first path, and the second path are conducting, respectively. Based on the voltage acquired by the sampling module, the detection module can determine the equivalent resistance between the positive terminal of the battery and ground, and the equivalent resistance between the negative terminal of the battery and ground, enabling insulation detection of the battery terminal. The third and fourth voltage divider modules connect the equivalent resistance between the positive terminal of the load and ground, and the equivalent resistance between the negative terminal of the load and ground, to the battery terminal. The sampling module acquires the voltage at the first sampling point, and the detection module can perform insulation detection of the load terminal based on the voltage acquired by the sampling module. Therefore, the solution of this application can still achieve insulation detection of the load terminal when the load terminal and the battery terminal are not connected, improving the accuracy of insulation detection.

[0187] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0188] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. An insulation detection circuit, characterized in that, include: Sampling module, detection module, first voltage divider module, second voltage divider module, third voltage divider module, fourth voltage divider module; One end of the first voltage divider module is connected to the positive terminal of the battery, and the other end of the first voltage divider module is grounded; one end of the second voltage divider module is connected to the negative terminal of the battery, and the other end of the second voltage divider module is grounded; one end of the third voltage divider module is connected to the positive terminal of the load, and the other end of the third voltage divider module is connected to the negative terminal of the battery; one end of the fourth voltage divider module is connected to the negative terminal of the load, and the other end of the fourth voltage divider module is connected to the negative terminal of the battery. The sampling module is connected to the first voltage divider module, the second voltage divider module, the third voltage divider module, and the fourth voltage divider module, and is used to collect the voltage at the location of the first sampling point under different states; wherein, the different states include: the first path from the negative terminal of the battery terminal through the second voltage divider module to ground is in a conductive state; the first path and the second path from the positive terminal of the battery terminal through the first voltage divider module to ground are in a conductive state; the first path and the third path from the positive terminal of the load terminal through the third voltage divider module to the negative terminal of the battery terminal are in a conductive state; the first path and the negative terminal of the load terminal through the fourth voltage divider module to the negative terminal of the battery terminal are in a conductive state. The detection module is connected to the sampling module and is used to perform insulation detection on the battery terminal and / or load terminal based on the voltage collected by the sampling module.

2. The insulation detection circuit according to claim 1, characterized in that, The second voltage divider module includes: a first resistor, a second resistor, and a first switch; One end of the first resistor is connected to the negative terminal of the battery, and the other end of the first resistor is connected to one end of the second resistor. The connection point of the first resistor and the second resistor is used as the first sampling point and connected to the sampling module. The other end of the second resistor is connected to one end of the first switch; the other end of the first switch is grounded.

3. The insulation detection circuit according to claim 2, characterized in that, The first voltage divider module includes: a third resistor and a second switch; One end of the third resistor is connected to the positive terminal of the battery, and the other end of the third resistor is connected to one end of the second switch; The other end of the second switch is connected to the other end of the first switch and grounded.

4. The insulation detection circuit according to claim 2, characterized in that, The third voltage divider module includes: a fourth resistor, a fifth resistor, and a third switch; One end of the fourth resistor is connected to the positive terminal of the load terminal, and the other end of the fourth resistor is connected to one end of the third switch; The other end of the third switch is connected to one end of the fifth resistor, and the connection point between the third switch and the fifth resistor is used as the second sampling point and connected to the sampling module. The other end of the fifth resistor is connected to the negative terminal of the battery.

5. The insulation detection circuit according to claim 2, characterized in that, The fourth voltage divider module includes: a sixth resistor, a seventh resistor, and a fourth switch; One end of the sixth resistor is connected to the negative terminal of the load terminal, and the other end of the sixth resistor is connected to one end of the fourth switch; The other end of the fourth switch is connected to one end of the seventh resistor, and the connection point between the fourth switch and the seventh resistor is used as the third sampling point and connected to the sampling module. The other end of the seventh resistor is connected to the negative terminal of the battery.

6. The insulation detection circuit according to any one of claims 1-5, characterized in that, The insulation detection circuit further includes: a first capacitor, a fifth switch, a sixth switch, a seventh switch, and an eighth resistor; One end of the first capacitor is connected to the positive terminal of the load terminal, and the other end of the first capacitor is connected to the negative terminal of the load terminal; The fifth switch is connected in series on the transmission path between the positive terminal of the battery and the positive terminal of the load. One end of the sixth switch is connected to the positive terminal of the battery, and the other end of the sixth switch is connected to one end of the eighth resistor; the other end of the eighth resistor is connected to the positive terminal of the load. The seventh switch is connected in series on the transmission path between the negative terminal of the battery and the negative terminal of the load.

7. An insulation testing method, characterized in that, Based on the insulation detection circuit as described in any one of claims 1-6, the method includes: Control the first path to conduct, and obtain the first voltage sampled by the sampling module at the first sampling point; Control the first and second paths to conduct, and obtain the second voltage sampled by the sampling module at the first sampling point position; Control the first and third paths to conduct, and obtain the third voltage sampled by the sampling module at the first sampling point; Control the first path and the fourth path to conduct, and obtain the fourth voltage sampled by the sampling module at the first sampling point position; Insulation testing is performed on the battery terminal and / or load terminal based on the first voltage, the second voltage, the third voltage, and the fourth voltage.

8. The method according to claim 7, characterized in that, Before performing insulation detection on the battery terminal and / or load terminal based on the first voltage, the second voltage, the third voltage, and the fourth voltage, the method further includes: Determine whether the fifth and seventh switches are conducting; if they are not conducting, then perform insulation detection on the battery terminal and / or load terminal based on the first voltage, the second voltage, the third voltage, and the fourth voltage. If conduction is achieved, the method further includes: Insulation tests are performed on the battery terminals and / or load terminals based on the first voltage and the second voltage.

9. The method according to claim 7 or 8, characterized in that, The insulation detection of the battery terminal and / or load terminal based on the first voltage, the second voltage, the third voltage, and the fourth voltage includes: Based on Kirchhoff's laws, establish the first equation corresponding to the first voltage and the second equation corresponding to the second voltage, respectively; Based on the first equation and the second equation, a system of equations is established to calculate the equivalent resistance of the positive electrode and the equivalent resistance of the negative electrode at the battery terminal. Establish a third solution corresponding to the third voltage based on Kirchhoff's laws, and solve the third solution to obtain the equivalent resistance of the positive terminal of the load. Based on Kirchhoff's laws, establish the fourth equation corresponding to the fourth voltage, and solve the fourth equation to obtain the equivalent resistance of the positive terminal of the load. Insulation testing is performed on the battery terminals and / or load terminals based on the equivalent resistance of the positive terminal of the battery terminal, the equivalent resistance of the negative terminal of the battery terminal, the equivalent resistance of the positive terminal of the load terminal, and the equivalent resistance of the positive terminal of the load terminal.

10. A car, characterized in that, include: The insulation detection circuit as described in any one of claims 1-6.

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