Electric leakage detection device

Abstract

An electric leakage detection device (20) is provided with: a first voltage division circuit (30); a second voltage division circuit (40); a switch unit (50) configured so as to be able to switch between a power-on state and a power-off state of the second voltage divider circuit; and a control unit (70) that detects electric leakage. The control unit performs: a first input step in which a second voltage division circuit is switched to a power-on state, a first voltage division value from the first voltage division circuit is input, and a second voltage division value from the second voltage division circuit is input; a second input step of switching the second voltage division circuit to an energization cut-off state and inputting a third voltage division value from the first voltage division circuit; a characteristic determination step of determining whether there is no abnormality in the first voltage division circuit and the second voltage division circuit on the basis of the first voltage division value and the second voltage division value; and an electric leakage detection step of detecting electric leakage based on the first partial voltage value and the third partial voltage value.

Description

Citation of related applications

[0001] This application is based on Japanese Patent Application No. 2022-079779 filed on May 13, 2022, and the contents thereof are incorporated herein by reference. Technical Field

[0002] The present application discloses a leakage detection device. Background Art

[0003] In the past, a vehicle such as a hybrid vehicle or an electric vehicle was equipped with a high-voltage battery and a high-voltage circuit. In such a vehicle, the high-voltage circuit is generally electrically insulated from the vehicle body (vehicle body ground, frame ground) to ensure safety. In addition, in this case, a leakage detection device (insulation resistance detection circuit) is generally provided for detecting the insulation state (ground fault) between the high-voltage circuit and the vehicle body (for example, Patent Document 1).

[0004] The leakage detection circuit described in Patent Document 1 is configured to detect insulation resistance and to detect a decrease in detection accuracy due to aging or poor contact of a detection resistor constituting a voltage divider circuit. Prior art literature Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-50964 Summary of the invention

[0006] However, in the leakage detection circuit of Patent Document 1, the insulation resistance is detected after determining whether the value of the detection resistor is normal. In addition, in order to determine whether the value of the detection resistor is normal, a dedicated switch pattern needs to be provided in addition to the switch pattern used to detect the insulation resistance, so time is spent for switch switching and signal measurement. Therefore, it is difficult to determine whether the value of the detection resistor is normal during a limited period such as when the vehicle starts, and to always monitor the abnormality of the detection resistor during driving. Therefore, it is difficult to deal with the situation in which an abnormality occurs in the voltage divider circuit due to the mixing of foreign matter during driving.

[0007] The present disclosure is made to solve the above-mentioned problems, and an object of the present disclosure is to provide a leakage detection device capable of efficiently performing characteristic determination and leakage detection of a voltage divider circuit.

[0008] The leakage detection device for solving the above problem is a leakage detection device for detecting leakage between a power path connected to a terminal of a battery and a grounding member, comprising: A first voltage divider circuit, one end of which is connected to the power path side and the other end of which is connected to the grounding member side, thereby being in an energized state; A second voltage divider circuit, one end of which is connected to the power supply path side and the other end of which is connected to the grounding member side and is connected in parallel with the first voltage divider circuit, thereby being in an energized state; a switch unit configured to switch between a power-on state and a power-off state of the second voltage dividing circuit; and a control unit that controls the switch unit, inputs the voltage division value of the first voltage division circuit, detects leakage, The control unit is configured to receive the voltage division values ​​from the first voltage division circuit and the second voltage division circuit, and implement: a first input step of controlling the switch section to switch the second voltage dividing circuit to an on state, inputting a first voltage dividing value from the first voltage dividing circuit, and inputting a second voltage dividing value from the second voltage dividing circuit; a second input step, after the first input step, controlling the switch unit to switch the second voltage divider circuit to a power-on / off state, and inputting a third voltage divider value from the first voltage divider circuit; a characteristic determination step of determining whether the first voltage dividing circuit and the second voltage dividing circuit are free of abnormality based on the first voltage dividing value and the second voltage dividing value; and A leakage detection step is performed to detect leakage based on the first divided voltage value and the third divided voltage value.

[0009] According to the above structure, in the first input step, while inputting the first voltage divider value for leakage detection and characteristic determination, the second voltage divider value for characteristic determination is input. Then, through the second input step implemented after the first input step, the third voltage divider value for leakage detection is input. Thus, during the implementation of the first input step and the second input step required for leakage detection, more specifically, during the implementation of the first input step, the first voltage divider value and the second voltage divider value required for characteristic determination can be input. Therefore, there is no need to switch the switch part and set the time for measuring the voltage divider value only to obtain the first voltage divider value and the second voltage divider value required for characteristic determination, and leakage detection and characteristic determination can be efficiently implemented. Therefore, characteristic determination can be implemented at the same time as leakage detection, and abnormality of the voltage divider circuit can be determined at all times during driving, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above objects, other objects, features and advantages of the present disclosure will become more apparent with reference to the accompanying drawings and the following detailed description. Figure 1 It is a structural diagram of the vehicle power system. Figure 2 This is a flow chart of the leakage detection process. Figure 3 is a schematic diagram showing the connection state of the voltage dividing circuit. Figure 4 : is a timing chart showing the input timing of the divided voltage value. Figure 5 It is a diagram for explaining the detection error of the voltage dividing circuit. Figure 6 This is a flowchart of the leakage detection process according to the second embodiment. Figure 7 : is a timing chart showing the input timing of the initial value. Figure 8 It is a configuration diagram of a leakage detection device according to a third embodiment. Fig. 9 : is a timing chart showing the input timing of the initial value in the comparative example. Fig.10 1 is a timing chart showing the input timing of the initial value in the third embodiment. Fig.11 It is a diagram showing the voltage across the insulation resistance when it decreases. Fig.12 This is a diagram for explaining the error of the calculated value. Fig.13 This is a flowchart of the leakage detection process according to the fourth embodiment. Fig.14 It is a structural diagram of a leakage detection device according to a modified example. Fig.15 It is a structural diagram of a leakage detection device according to a modified example. Fig.16 It is a structural diagram of a leakage detection device according to a modified example. DETAILED DESCRIPTION

[0011] Hereinafter, a first embodiment is described with reference to the accompanying drawings, in which a "leakage detection device" is applied to a vehicle power supply system of a vehicle (e.g., a hybrid vehicle or an electric vehicle) including a rotating electrical machine as a vehicle main unit. In addition, in each of the following embodiments, the same or equivalent parts are marked with the same symbols in the drawings, and the description of the parts with the same symbols is cited.

[0012] (First Embodiment) Figure 1 The vehicle power supply system 100 shown includes a battery pack 10 as a battery, a leakage detector 20, etc. Although not shown or described, electric loads such as rotating electrical machines are connected to the positive power supply path L1 and the negative power supply path L2 connected to the battery pack 10.

[0013] The battery pack 10 is, for example, a storage battery having an inter-terminal voltage V1 of 800 V. The battery pack 10 is formed by connecting a plurality of battery cells. As the battery cells, for example, a lithium ion storage battery or a nickel-metal hydride storage battery can be used.

[0014] The positive-side power supply path L1 (equivalent to a power line) connected to the positive-side power supply terminal of the battery pack 10 is electrically insulated from the vehicle-side grounding member FG such as a vehicle body. The vehicle-side grounding member FG is a vehicle body, etc., and is equivalent to the frame grounding. The insulation state (insulation resistance to ground) between the positive-side power supply path L1 and the vehicle-side grounding member FG can be expressed as an insulation resistance Rp.

[0015] Similarly, the negative-side power supply path L2 connected to the negative-side power supply terminal of the battery pack 10 is electrically insulated from the vehicle-side ground FG. The insulation state (insulation resistance to ground) between the negative-side power supply path L2 and the vehicle-side ground FG can be expressed as insulation resistance Rn. In addition, the negative-side power supply path L2 corresponds to the ground (signal ground SG) that determines the reference potential of the high-voltage circuit.

[0016] The leakage detector 20 is connected to the vehicle ground FG and the negative power supply path L2 to detect whether the positive power supply path L1 and the negative power supply path L2 are normally insulated from the vehicle ground FG, that is, leakage (ground fault).

[0017] The leakage detection device 20 is described in detail. The leakage detection device 20 includes: a first voltage divider circuit 30; a second voltage divider circuit 40 connected in parallel with the first voltage divider circuit 30; a switch unit 50 configured to switch the power-on state and the power-off state of the first voltage divider circuit 30 and the second voltage divider circuit 40, respectively; a detection circuit 60; and a control device 70 as a control unit for detecting leakage.

[0018] One end of the first voltage divider circuit 30 is connected to the negative-side power supply path L2 side, and the other end is connected to the vehicle-side grounding member FG side, and the voltage between the negative-side power supply path L2 and the vehicle-side grounding member FG (the voltage across the first voltage divider circuit 30) is divided by a voltage division ratio α. The structure is described in detail. The first voltage divider circuit 30 has a first A detection resistor 30a and a first B detection resistor 30b, and is composed of a series connection body in which they are connected in series. The first A detection resistor 30a is connected to the vehicle-side grounding member FG side, and the first B detection resistor 30b is connected to the negative-side power supply path L2 side. The first connection point P1 between the first A detection resistor 30a and the first B detection resistor 30b is connected to one end of the first output line L11, and the voltage signal (voltage division value) from the first voltage divider circuit 30 is output via the first output line L11.

[0019] One end of the second voltage divider circuit 40 is connected to the negative side power supply path L2 side, and the other end is connected to the vehicle side grounding piece FG side, and the voltage between the negative side power supply path L2 and the vehicle side grounding piece FG (the voltage across the second voltage divider circuit 40) is divided by a voltage divider ratio β. The structure is described in detail. The second voltage divider circuit 40 has a second A detection resistor 40a and a second B detection resistor 40b, which are connected in series. The second A detection resistor 40a is connected to the vehicle side grounding piece FG side, and the second B detection resistor 40b is connected to the negative side power supply path L2 side. The second connection point P2 between the second A detection resistor 40a and the second B detection resistor 40b is connected to one end of the second output line L12, and the voltage signal (voltage divider value) from the second voltage divider circuit 40 is output via the second output line L12.

[0020] Next, the switch unit 50 will be described. The switch unit 50 includes a first switch Si and a second switch Sz, which are configured to be controlled to be turned on and off by the control device 70.

[0021] One end of the first switch Si is connected to the vehicle-side grounding member FG, and the other end is connected in series to one end of the second switch Sz. In addition, the connection point P3 between the first switch Si and the second switch Sz is connected to the first voltage divider circuit 30. In more detail, the connection point P3 between the first switch Si and the second switch Sz is connected to one end of the first A detection resistor 30a (the end on the opposite side of the first connection point P1). One end of the second switch Sz is connected in series to the first switch Si, and the other end is connected to the second voltage divider circuit 40. In more detail, the other end of the second switch Sz is connected to one end of the second A detection resistor 40a (the end on the opposite side of the second connection point P2).

[0022] Moreover, as described above, one end of the first voltage divider circuit 30 (one end of the first B detection resistor 30b on the opposite side of the first connection point P1) is connected to the negative side power supply path L2. In addition, the other end of the first voltage divider circuit 30 (one end of the first A detection resistor 30a on the opposite side of the first connection point P1) is connected to the connection point P3 between the first switch Si and the second switch Sz, and is connected in series with the vehicle side grounding member FG via the first switch Si. Therefore, when the first switch Si is turned on, the first voltage divider circuit 30 is switched to the power-on state, and when the first switch Si is turned off, the first voltage divider circuit 30 is switched to the power-off state.

[0023] Similarly, one end of the second voltage divider circuit 40 (one end of the second B detection resistor 40b on the opposite side of the second connection point P2) is connected to the negative side power supply path L2. In addition, the other end of the second voltage divider circuit 40 (one end of the second A detection resistor 40a on the opposite side of the second connection point P2) is connected in series with one end of the second switch Sz on the opposite side of the first switch Si (on the opposite side of the connection point P3), and is connected in series with the vehicle side grounding member FG via the second switch Sz and the first switch Si. Therefore, when both the first switch Si and the second switch Sz are turned on, the second voltage divider circuit 40 is switched to the power-on state, and when either the first switch Si or the second switch Sz is turned off, the second voltage divider circuit 40 is switched to the power-off state.

[0024] That is, by turning off the first switch Si, the first voltage divider circuit 30 and the second voltage divider circuit 40 can be disconnected from the vehicle-side ground FG and switched to the energized cutoff state. In addition, by turning off the second switch Sz, regardless of the state of the first voltage divider circuit 30, the second voltage divider circuit 40 can be disconnected from the vehicle-side ground FG and switched to the energized cutoff state.

[0025] When both the first switch Si and the second switch Sz are turned on, both the first voltage divider circuit 30 and the second voltage divider circuit 40 can be switched to the energized state. When the first switch Si is turned on and the second switch Sz is turned off, only the first voltage divider circuit 30 can be switched to the energized state.

[0026] The detection circuit 60 is composed of a first detection circuit 61 configured on the first output line L11 and a second detection circuit 62 configured on the second output line L12. The first detection circuit 61 is composed of a filter circuit and the like, and outputs a signal from a signal input via the first output line L11, such as a signal removed from noise, to the control device 70 as a signal from the first voltage divider circuit 30. Similarly, the second detection circuit 62 is composed of a filter circuit and the like, and outputs a signal from a signal input via the second output line L12, such as a signal removed from noise, to the control device 70 as a signal from the second voltage divider circuit 40.

[0027] The control device 70 is mainly composed of a microcomputer having a CPU, ROM, RAM, and I / O, and various functions are realized by the CPU executing the program stored in the ROM. In addition, various functions can be realized by electronic circuits as hardware, or at least part of them can be realized by software, that is, processing executed on a computer. The control device 70 has a function of controlling the on / off state of the first switch Si and the second switch Sz constituting the switch unit 50, a function of detecting leakage, etc. In addition, a switch control unit having a function of controlling the on / off state of various switches, etc. can be provided separately from the control device 70, and cooperates with the control device 70 to detect leakage.

[0028] The control device 70 estimates the values ​​of the insulation resistances Rp and Rn based on the signals (voltage divider values) input from the first voltage divider circuit 30 and the second voltage divider circuit 40, and detects leakage. Therefore, when the detection resistors 30a, 30b, 40a, and 40b constituting the first voltage divider circuit 30 and the second voltage divider circuit 40 are abnormal and the voltage divider values ​​have errors, the detection accuracy of leakage is reduced. For example, if the values ​​of the detection resistors 30a, 30b, 40a, and 40b change due to years of degradation, poor contact, foreign matter mixing, disconnection, short circuit, etc., the detection accuracy of leakage is reduced. Therefore, in this embodiment, a characteristic determination is performed, and the characteristic determination determines whether the characteristics of the first voltage divider circuit 30 and the second voltage divider circuit 40 are not abnormal. In addition, in this embodiment, the characteristic determination is implemented in the leakage detection so that it can always be implemented even when driving. The following is a detailed description of the leakage detection process.

[0029] Figure 2 The flow of the leakage detection process is shown below. The leakage detection process is performed by the control device 70 at every predetermined cycle (for example, every several tens of ms).

[0030] First, the control device 70 turns on the first switch Si (step S1) and turns on the second switch Sz (step S2). Figure 3 As shown in the schematic diagram of (a), the first voltage divider circuit 30 and the second voltage divider circuit 40 are both energized, and as a result, the first voltage divider circuit 30, the second voltage divider circuit 40 and the insulation resistor Rn are connected in parallel between the negative side power supply path L2 and the vehicle side grounding member FG.

[0031] like Figure 4 As shown, at this time, in order to stabilize the signal, the control device 70 waits until a predetermined time (time T1 to time T2) has passed since the first switch Si and the second switch Sz were both switched on (time T1). Then, at the time (time T2) when the predetermined time has passed, the control device 70 inputs the first voltage division value αVn1 from the first voltage division circuit 30 via the first detection circuit 61 (step S3). In addition, at this time (time T2), the control device 70 inputs the second voltage division value βVr1 from the second voltage division circuit 40 via the second detection circuit 62 (step S3).

[0032] In addition, Figure 4 In the figure, the voltage across the insulation resistor Rn is equivalent to "Vg", and "Vg0" is equivalent to the voltage across the insulation resistor Rn when both the first voltage divider circuit 30 and the second voltage divider circuit 40 are in the power-on and power-off state. Figure 3 As shown in (a), "Vg1" corresponds to the voltage across the insulation resistor Rn when both the first voltage divider circuit 30 and the second voltage divider circuit 40 are energized. Figure 3As shown in (b), "Vg2" corresponds to the voltage across the insulation resistor Rn when the first voltage dividing circuit 30 is in the energized state and the second voltage dividing circuit 40 is in the energized and de-energized state.

[0033] The first voltage division value is equivalent to the value "αVn1" obtained by multiplying the voltage across the first voltage division circuit 30 by the voltage division ratio α when both the first voltage division circuit 30 and the second voltage division circuit 40 are in the power-on state. The second voltage division value is equivalent to the value "βVr1" obtained by multiplying the voltage across the second voltage division circuit 40 by the voltage division ratio β when both the first voltage division circuit 30 and the second voltage division circuit 40 are in the power-on state.

[0034] Therefore, in step S3, the control device 70 divides the input first voltage division value αVn1 by the voltage division ratio α, thereby calculating the voltage across the first voltage division circuit 30 (hereinafter, referred to as the detection voltage Vn1). Similarly, in step S3, the control device 70 divides the input second voltage division value βVr1 by the voltage division ratio β, thereby calculating the voltage across the second voltage division circuit 40 (hereinafter, referred to as the detection voltage Vr1). In addition, the calculation of the detection voltages Vn1 and Vr1 can also be implemented in step S6 described later.

[0035] Next, the control device 70 turns off the second switch Sz while the first switch Si is turned on (step S4). Figure 3 As shown in (b), the first voltage dividing circuit 30 remains energized and the second voltage dividing circuit 40 is de-energized. As a result, the first voltage dividing circuit 30 and the insulation resistor Rn are connected in parallel between the negative power supply path L2 and the vehicle ground FG.

[0036] like Figure 4 As shown, at this time, in order to stabilize the signal, the control device 70 waits for a predetermined time (time T3 to time T4) from the moment when the second switch Sz is switched off (time T3). Then, at the moment when the predetermined time has passed (time T4), the control device 70 inputs the third voltage division value αVn2 from the first voltage division circuit 30 via the first detection circuit 61 (step S5). In addition, in step S5, the control device 70 divides the input third voltage division value αVn2 by the voltage division ratio α, thereby calculating the voltage across the first voltage division circuit 30 (hereinafter referred to as the detection voltage Vn2). In addition, the calculation of the detection voltage Vn2 can also be implemented in step S7 described later.

[0037] After that, the control device 70 performs characteristic determination of whether the first voltage divider circuit 30 and the second voltage divider circuit 40 have no abnormality (step S6). Specifically, by determining whether Vn1 / Vr1 is approximately 1, it is determined whether the first voltage divider circuit 30 and the second voltage divider circuit 40 have no abnormality. That is, it is determined whether the value of Vn1 / Vr1 is within a prescribed range close to 1 (1-x<Vn1 / Vr1<1+y: x and y are arbitrary values ​​set in consideration of the required calculation accuracy). When the value of Vn1 / Vr1 is within a prescribed range close to 1, it is determined that there is no abnormality, and if it is not within the prescribed range, it is determined that there is an abnormality.

[0038] In addition, the control device 70 may also perform characteristic determination by determining whether Vn1 and Vr1 are substantially the same value. That is, Vn1 and Vr1 are compared to determine whether the difference is less than a predetermined determination value (an arbitrary value set in consideration of the required calculation accuracy). If the difference is less than the determination value, it is determined that there is no abnormality, and if it is greater than the determination value, it is determined that there is an abnormality.

[0039] When the determination result is positive (no abnormality), the control device 70 calculates the insulation resistance based on Vn1 and Vn2 (step S7), and determines leakage based on whether the value is less than the leakage determination threshold value (step S8). Step S7 will be described.

[0040] like Figure 3 As shown in (a), "Vn1" is the voltage across the first voltage divider circuit 30 when the first voltage divider circuit 30, the second voltage divider circuit 40, and the insulation resistor Rn are connected in parallel between the negative-side power supply path L2 and the vehicle-side grounding member FG, so it can be expressed as shown in formula (1). In addition, the value of the resistance (composite resistance) of the first voltage divider circuit 30 is set to "R1", and the value of the resistance (composite resistance) of the second voltage divider circuit 40 is set to "R2". The voltage across the battery pack 10 is "V1".

[0041] [Mathematical formula 1] In addition, if Figure 3 As shown in (b), "Vn2" is the voltage across the first voltage divider circuit 30 when the first voltage divider circuit 30 and the insulation resistor Rn are connected in parallel between the negative-side power supply path L2 and the vehicle-side ground member FG, so it can be expressed as shown in formula (2).

[0042] [Mathematical formula 2] Then, as shown in equations (3) to (4), the insulation resistances Rp and Rn can be obtained from equations (1) to (2). Alternatively, the voltage V1 between the terminals of the battery pack 10 can be eliminated to obtain a composite equation for the insulation resistances Rp and Rn (equation (5)).

[0043] [Mathematical formula 3] In step S8, the control device 70 detects leakage based on whether the value of the composite formula of the insulation resistances Rp and Rn shown in formula (5) is less than a predetermined leakage determination threshold value Th. In step S8, the control device 70 may also detect leakage based on whether the insulation resistance Rp calculated by formula (3) and the insulation resistance Rn calculated by formula (4) are less than the set leakage determination threshold values ​​Rp0 and Rn0, respectively.

[0044] If the result of the determination in step S8 is positive (if leakage is detected), the control device 70 implements a process for corresponding to leakage (step S9), and ends the leakage detection process. The process for corresponding to leakage refers to, for example, a process for notifying an external device of leakage and issuing a warning. On the other hand, if the result of the determination in step S8 is negative (if leakage is not detected), the control device 70 considers that the device is normal and ends the leakage detection process directly.

[0045] On the other hand, when the determination result of step S6 is negative (when there is a characteristic abnormality), the control device 70 considers that an abnormality has occurred in the first voltage divider circuit 30 or the second voltage divider circuit 40, implements a process for responding to the abnormality of the voltage divider circuit 30, 40 (step S10), and ends the leakage detection process. The process for responding to the abnormality of the voltage divider circuit 30, 40 is, for example, a process for notifying the external device of the abnormality, warning that leakage detection cannot be performed, and the like.

[0046] Next, the effects of the first embodiment will be described.

[0047] (1) In the first input step (equivalent to steps S1 to S3), the control device 70 switches both the first switch Si and the second switch Sz to on, and inputs the first voltage division value αVn1 and the second voltage division value βVr1. Thereafter, in the second input step (equivalent to steps S4 to S5), the control device 70 switches the second switch Sz to off, and inputs the third voltage division value αVn2.

[0048] Then, the control device 70 performs a characteristic determination step (equivalent to step S6) based on the first voltage division value αVn1 and the second voltage division value βVr1. Specifically, the control device 70 calculates the detection voltages Vn1 and Vr1 based on the first voltage division value αVn1 and the second voltage division value βVr1, and compares the detection voltage Vn1 with the detection voltage Vr1 to perform the characteristic determination.

[0049] In addition, the control device 70 implements a leakage detection step (equivalent to steps S7 to S8) based on the first divided voltage value αVn1 and the third divided voltage value αVn2. Specifically, the control device 70 calculates the detection voltages Vn1 and Vn2 based on the first divided voltage value αVn1 and the third divided voltage value αVn2, calculates the insulation resistances Rn and Rp based on equations (3) and (4), or calculates the value of the composite formula of the insulation resistances Rn and Rp shown in equation (5), and compares it with the leakage judgment threshold value to detect leakage.

[0050] Thus, during the first input step and the second input step (steps S1 to S5) required for the leakage detection, more specifically, during the first input step (steps S1 to S3), the first voltage divider value and the second voltage divider value required for the characteristic determination can be input. Therefore, there is no need to switch the switch unit 50 and set the time for measurement just to obtain the first voltage divider value and the second voltage divider value required for the characteristic determination, and the leakage detection and characteristic determination can be efficiently performed. Therefore, the characteristic determination can be performed at the same time as the leakage detection, and the abnormality of the voltage divider circuits 30 and 40 can be determined at all times during driving, etc.

[0051] (2) When leakage is detected by calculating the value of the composite formula of the insulation resistances Rn and Rp shown in formula (5), it is not necessary to measure the inter-terminal voltage V1 of the battery pack 10. Therefore, the measurement error of the inter-terminal voltage V1 can be ignored, and the accuracy of leakage detection is improved.

[0052] (3) One end of the first voltage divider circuit 30 is connected to the negative-side power supply path L2, and the other end is connected to the connection point P3 between the first switch Si and the second switch Sz, and is connected in series with the vehicle-side grounding member FG via the first switch Si. In addition, one end of the second voltage divider circuit 40 is connected to the negative-side power supply path L2, and the other end is connected in series with one end of the second switch Sz that is not connected to the first switch Si (the side opposite to the connection point P3), and is connected in series with the vehicle-side grounding member FG via the second switch Sz and the first switch Si. By adopting such a circuit structure, the number of switches used in the leakage detection device 20 can be reduced to two. In particular, when it is desired to completely insulate and separate the vehicle-side grounding member FG and the negative-side power supply path L2 (and the positive-side power supply path L1), a high-voltage mechanical relay is preferred, but it is sufficient to set the first switch Si that can make the first voltage divider circuit 30 and the second voltage divider circuit 40 both in the power-on and power-off state as a mechanical relay, so the number of mechanical relays can be reduced.

[0053] (Second Embodiment) A part of the structure of the first embodiment may be modified as follows: Since the circuit structure of the leakage detection device 20 is the same as that of the first embodiment, the description thereof will be omitted.

[0054] In the first embodiment, when the first voltage division value and the second voltage division value are used to perform characteristic determination, an erroneous determination may be caused due to errors in the circuit characteristics of each voltage division circuit 30, 40. Figure 5 As shown in (a), consider the following situation: according to the circuit characteristics of the first voltage divider circuit 30, an error Vd1 is generated in the detection voltage Vn calculated based on its voltage divider value αVn, and according to the circuit characteristics of the second voltage divider circuit 40, an error Vd2 is generated in the detection voltage Vr calculated based on its voltage divider value βVr.

[0055] In this case, the original words (if there is no error, refer to Figure 5 (b)), the detection voltage Vn1 and the detection voltage Vr1 are inconsistent, and the characteristic should be considered abnormal. Figure 5 As shown in (a), due to the errors Vd1 and Vd2, the detection voltage Vn1 and the detection voltage Vr1 may match and be judged as normal. In this way, due to the errors Vd1 and Vd2 caused by the characteristics of the voltage divider circuits 30 and 40, it is possible to cause an erroneous judgment in the characteristic judgment.

[0056] Therefore, in the second embodiment, a part of the leakage detection process is changed to correct the deviation caused by the errors Vd1 and Vd2. Figure 6 The leakage detection process according to the second embodiment will be described.

[0057] When the leakage detection process is performed, the control device 70 first turns off the first switch Si (step S201) and turns off the second switch Sz (step S202). As a result, both the first voltage dividing circuit 30 and the second voltage dividing circuit 40 are in the energized cutoff state.

[0058] like Figure 7 As shown, at this time, in order to stabilize the signal, the control device 70 waits for a predetermined time (time T21 to time T22) from the time when the first switch Si and the second switch Sz are both switched off (time T21). Then, at the time when the predetermined time has passed (time T22), the control device 70 inputs the output value αVn0 from the first voltage divider circuit 30 through the first detection circuit 61 (step S203). In addition, at this time (time T22), the control device 70 inputs the output value βVr0 from the second voltage divider circuit 40 through the second detection circuit 62 (step S203).

[0059] Then, in step S203, the control device 70 divides the input output value αVn0 by the voltage division ratio α, thereby calculating the voltage across the first voltage divider circuit 30 in the power-on and power-off state, that is, the first initial value Vn0. Similarly, in step S203, the control device 70 divides the input output value βVr0 by the voltage division ratio β, thereby calculating the voltage across the second voltage divider circuit 40 in the power-on and power-off state, that is, the second initial value Vr0. In addition, in an ideal state where no error occurs, the first initial value Vn0 and the second initial value Vr0 are zero. In the case of an error, each initial value Vn0 and Vr0 is equivalent to the error Vd1 and Vd2, respectively. In addition, the calculation of each initial value can also be implemented in step S204 described later.

[0060] Thereafter, steps S1 to S5 are performed in the same manner as in the first embodiment. After the execution of step S5, the control device 70 performs a correction step (step S204) of correcting the error in the circuit characteristics of the voltage divider circuits 30 and 40 based on the first initial value Vn0 and the second initial value Vr0. Specifically, in step S204, the control device 70 corrects the deviation in the first voltage divider circuit 30 based on the first initial value Vn0 acquired in the initial value acquisition step (equivalent to steps S201 to S203). That is, the control device 70 updates the value (Vn1-Vn0) obtained by subtracting the first initial value Vn0 from the detection voltage Vn1 to the corrected detection voltage Vn1. Similarly, the value (Vn2-Vn0) obtained by subtracting the first initial value Vn0 from the detection voltage Vn2 is updated to the corrected detection voltage Vn2.

[0061] In addition, the control device 70 corrects the deviation in the second voltage dividing circuit 40 based on the second initial value Vr0 acquired in the initial value acquisition step. That is, the control device 70 updates the value (Vr1-Vr0) obtained by subtracting the second initial value Vr0 from the detection voltage Vr1 to the corrected detection voltage Vr1. Thereafter, the control device 70 performs the processing after step S6 based on the corrected (updated) detection voltages Vn1, Vn2, and Vr1 in the same manner as in the first embodiment.

[0062] The second embodiment has the following effects in addition to the effects (1) to (3) of the first embodiment.

[0063] (4) The control device 70 puts both the first voltage divider circuit 30 and the second voltage divider circuit 40 in the power-on and power-off states, and obtains the first initial value Vn0 and the second initial value Vr0 corresponding to the errors caused by their circuit characteristics. Then, the control device 70 corrects the deviations of the detection voltages Vn1, Vn2, and Vr1 based on these initial values ​​Vn0 and Vr0, and performs characteristic determination and leakage detection after updating. Therefore, the accuracy of characteristic determination and leakage detection can be improved.

[0064] (Third Embodiment) A part of the structure of the second embodiment may be modified as follows.

[0065] In the leakage detection device 20, as Figure 1 As shown, noise is eliminated by inputting the voltage division value from the first voltage division circuit 30 via the first detection circuit 61.

[0066] However, when the first switch Si is turned on and the voltage division value is obtained from the first voltage division circuit 30 in the power-on state, it will be affected by the common noise of the vehicle side grounding member FG. Since the common noise of the vehicle side grounding member FG is large, it is necessary to adopt a filter circuit that can eliminate it in the first detection circuit 61 and the second detection circuit 62. For example, when the filter circuits of the first detection circuit 61 and the second detection circuit 62 are composed of RC low-pass filters, it is necessary to increase the value of the resistor and the capacitance of the capacitor. In addition, the same is true when the voltage division value is input from the second voltage division circuit 40 in the power-on state via the second detection circuit 62.

[0067] However, in the case of a heavy filter circuit in which the value of the resistor and the capacitance of the capacitor are increased, the time constant also becomes larger, so in the second embodiment, there is a problem that the time required to obtain the initial value becomes longer. Fig. 9 As shown, the third divided voltage value αVn2 is obtained from the first voltage dividing circuit 30 (time T4), and then, in order to obtain an initial value, the first switch Si is turned off (step S201).

[0068] At this time, when a heavy filter circuit with a large time constant is used in the first detection circuit 61, it is necessary to extend the waiting time (T21-T22) required from the moment T21 when the first switch Si is turned off to the moment T22 when the output value αVn0 is obtained. In other words, the waiting time until the voltage signal is sufficiently reduced and becomes a stable value becomes longer. Therefore, the time Ta required to obtain the initial value becomes longer.

[0069] Therefore, in the third embodiment, if Figure 8 As shown in FIG. 1 , a part of the first detection circuit 61 in the leakage detection device 20 is changed. The following is a description.

[0070] like Figure 8 As shown, the first detection circuit 161 of the third embodiment includes a first buffer 201, a heavy filter circuit 202 with a large time constant, a second buffer 203, and a light filter circuit 204 with a smaller time constant than the heavy filter circuit 202. The heavy filter circuit 202 and the light filter circuit 204 are RC low-pass filters, respectively, and the value of the resistor and the capacitance of the capacitor constituting the heavy filter circuit 202 are larger than those of the light filter circuit 204.

[0071] The first buffer 201 and the re-filter circuit 202 are connected in series and arranged on the first output line L11. The control device 70 inputs the first voltage division value αVn1 and the third voltage division value αVn2 through the first buffer 201 and the re-filter circuit 202. In addition, the first buffer 201 inputs the signal from the first voltage division circuit 30 with high impedance and outputs it to the re-filter circuit 202 with low impedance.

[0072] Furthermore, the second buffer 203 and the light filter circuit 204 are connected in series, and are connected in parallel with the series connection body formed by the first buffer 201 and the heavy filter circuit 202. Specifically, a branch line L13 branching from the first output line L11 is provided between the first voltage divider circuit 30 (connection point P3) and the first buffer 201. The second buffer 203 and the light filter circuit 204 are provided on the branch line L13, and the control device 70 inputs and outputs the value αVn0 via the second buffer 203 and the light filter circuit 204.

[0073] The second detection circuit 62 has the same structure as that of the first embodiment. For example, the second detection circuit 62 is a series connection body composed of a first buffer 201 and a re-filter circuit 202 .

[0074] based on Fig. 9 , Fig.10 The function of the above structure will be described.

[0075] Fig. 9 FIG. 2 shows the transition of the detection voltages Vn and Vr when the light filtering circuit 204 is not used. Fig. 9 As shown, from time T21 to time T22, the output value αVn0 based on the initial value Vn0 is input via the refilter circuit 202, so it takes time for the detection voltage Vn to sufficiently decrease and become a stable value. Therefore, the time Ta required to obtain the initial value becomes longer.

[0076] Then, in Fig.10 The transition of the detection voltages Vn and Vr in the third embodiment is described in FIG. Fig.10 In FIG. 2 , the solid line indicates the transition of the detection voltage Vn calculated based on the signal input via the heavy filter circuit 202 , and the dotted line indicates the transition of the detection voltage Vn calculated based on the signal input via the light filter circuit 204 .

[0077] like Fig.10 As shown by the dotted line, when inputted via the light filter circuit 204 with a small time constant, the detection voltage Vn immediately decreases. Therefore, when inputted via the light filter circuit 204 with a small time constant, the waiting time (T21 to T22) required to become a stable value can be shortened compared to the case of inputting via the heavy filter circuit 202. Therefore, the time Tb required to obtain the initial value becomes longer.

[0078] In the third embodiment, the second detection circuit 62 is composed of the heavy filter circuit 202 as in the first embodiment. Fig.10 As shown in the detection voltage Vr, there is a sufficient time margin from turning off the second switch Sz (time T3) to inputting the output value βVr0 (time T22) which is the basis of the second initial value Vr0. Therefore, it is not necessary to provide a light filter circuit 204 like the first detection circuit 161. However, there is no problem even if the second detection circuit 62 is set to the same structure as the first detection circuit 161.

[0079] The third embodiment has the following effects in addition to the effects (1) to (3) of the first embodiment and the effect (4) of the second embodiment.

[0080] (5) When the negative-side power supply path L2 and the vehicle-side grounding member FG are energized via the first voltage divider circuit 30 and a signal from the first voltage divider circuit 30 is input, it is necessary to suppress the influence of the common noise from the vehicle-side grounding member FG. Therefore, when the first voltage divider circuit 30 is energized, the control device 70 needs to input a signal via the heavy filter circuit 202 having a large time constant. However, when the signal is input via the heavy filter circuit 202, since the time constant is large, it takes time for the signal to stabilize. Therefore, when the first voltage divider circuit 30 is in the energized disconnected state, the output value αVn0 is input via the light filter circuit 204 having a small time constant. Thus, the time (Ta→Tb) until the output value αVn0 serving as the basis of the initial value Vn0 is obtained can be shortened. In addition, when the negative-side power supply path L2 and the vehicle-side grounding member FG are in the energized disconnected state, the output value αVn0 is input from the first voltage divider circuit 30, so there is no need to worry about the influence of the common noise from the vehicle-side grounding member FG in the input of the output value αVn0.

[0081] (Fourth Embodiment) Part of the configuration of the first to third embodiments may be modified as follows. In the fourth embodiment, the configuration of the first embodiment is used as a reference, and the differences therefrom are described.

[0082] In the first embodiment, when leakage detection is performed based on the composite formula (Formula (5)) of the insulation resistances Rp and Rn, if the insulation resistances Rp and Rn decrease, the influence of the circuit tolerance may temporarily increase due to the composite formula.

[0083] like Fig.11 As shown in FIG. 1 , when the insulation resistance Rn decreases, the voltage Vg across the insulation resistance Rn decreases accordingly (Vga→Vgb). Accordingly, the voltage Vg1 across the insulation resistance Rn when both the first voltage divider circuit 30 and the second voltage divider circuit 40 are in the energized state, and the voltage Vg2 across the insulation resistance Rn when the first voltage divider circuit 30 is in the energized state and the second voltage divider circuit 40 is in the energized disconnected state also decrease. As a result, the detection voltages Vn1 and Vn2 also decrease and approach zero.

[0084] When the detection voltages Vn1 and Vn2 are close to zero, the influence of the circuit tolerance increases relatively. Therefore, there is a possibility that the detection voltages Vn1 and Vn2 are equal or the detection voltage Vn1 is greater than the detection voltage Vn2 and the magnitude is reversed. In this case, Fig.12 As shown, the values ​​diverge (are unstable) and cannot be evaluated normally or judged normally.

[0085] Therefore, in the leakage detection process of the fourth embodiment, if Fig.13As shown, when the detection voltages Vn1 and Vn2 become sufficiently small, a process for suppressing the influence of circuit tolerance and the like is added. This will be described below.

[0086] After the processing of step S6, the control device 70 determines whether the detection voltage Vn1 is greater than the first threshold value TL1 (step S301). The first threshold value TL1 is set to an arbitrary value in consideration of circuit tolerance, etc. Fig.13 In the case where the determination result is positive, that is, when the detection voltage Vn2 is greater than the first threshold TL1, the control device 70 determines whether the detection voltage Vn2 is greater than the second threshold TL2 (step S302). The second threshold TL2 is set to an arbitrary value taking into account circuit tolerance, etc. Fig.13 The first threshold TL1 and the second threshold TL2 may be the same value or different values.

[0087] When the determination result of step S302 is affirmative, it is considered that the determination can be made correctly based on the value calculated by equation (5), and the control device 70 performs the processing after step S7 in the same manner as in the first embodiment.

[0088] On the other hand, if the determination result of step S301 or step S302 is negative, the control device 70 sets a fixed value as the value of the synthetic equation of the insulation resistances Rp and Rn (step S303). The fixed value is a value indicating leakage and is determined according to the required specifications of the insulation resistances Rp and Rn.

[0089] After step S303, the control device 70 performs step S8 to detect leakage. In step S303, if a fixed value is set, it is determined that leakage has occurred.

[0090] The fourth embodiment has the following effects.

[0091] (6) When the insulation resistances Rp and Rn decrease and the detection voltages Vn1 and Vn2 approach zero, the influence of circuit tolerance and the like increases, and the value of the composite formula of the insulation resistances Rp and Rn may become unstable. Therefore, when the detection voltage Vn1 is below the first threshold TL1, or when the detection voltage Vn2 is below the second threshold TL2, the value of the composite formula of the insulation resistances Rp and Rn is not calculated, and leakage is detected. Thus, leakage can be accurately detected without being affected by circuit tolerance.

[0092] (Variation Example) A modification example in which a part of the above-described embodiment is changed will be described.

[0093] In the above embodiment, the control device 70 performs the detection of leakage and the process for coping with leakage, but it may be performed by an external device. In this case, the control device 70 may calculate the values ​​of the insulation resistances Rp and Rn and transmit them.

[0094] In the above embodiment, the leakage detection device 20 is connected between the negative-side power supply path L2 and the vehicle-side ground FG, but it may also be connected as follows. Fig.14 As shown, it is connected between the positive-side power supply path L1 and the vehicle-side grounding member FG. Fig.14 One end of the first voltage divider circuit 30 shown in the modified example is connected to the positive side power supply path L1 side, and the other end is connected to the vehicle side grounding member FG side, and the voltage between the positive side power supply path L1 and the vehicle side grounding member FG (the voltage across the first voltage divider circuit 30) is divided by a voltage division ratio α. Fig.14 The first A detection resistor 30a shown is connected to the positive-side power supply path L1 side, and the first B detection resistor 30b is connected to the vehicle-side ground FG side.

[0095] in addition, Fig.14 One end of the second voltage divider circuit 40 is connected to the positive side power supply path L1 side, and the other end is connected to the vehicle side grounding member FG side, and the voltage between the positive side power supply path L1 and the vehicle side grounding member FG (the voltage across the second voltage divider circuit 40) is divided by a voltage divider ratio β. Fig.14 The second A detection resistor 40a shown is connected to the positive side power supply path L1 side, and the second B detection resistor 40b is connected to the vehicle side ground FG side. Fig.14 One end of the first switch Si is connected to the positive power supply path L1, and the other end is connected in series to one end of the second switch Sz. The control device 70 inputs signals from the first voltage divider circuit 30 and the second voltage divider circuit 40 using the vehicle ground FG as a reference potential.

[0096] In the above embodiment, if Fig.15As shown, the configuration of the first switch Si and the second switch Sz may also be changed. That is, the first switch Si is connected between the first connection point P1 and the first A detection resistor 30a, and is configured to be able to switch the power-on state and the power-off state between the first connection point P1 and the first A detection resistor 30a. The second switch Sz is connected between the second connection point P2 and the second A detection resistor 40a, and is configured to be able to switch the power-on state and the power-off state between the second connection point P2 and the second A detection resistor 40a. In this case, the control device 70 does not need a differential amplifier circuit. In addition, if it is configured to be able to switch the power-on state between the first connection point P1 and the first A detection resistor 30a, the configuration of the first switch Si may also be changed between the first connection point P1 and the vehicle-side grounding member FG. Similarly, if it is configured to be able to switch the power-on state between the second connection point P2 and the second A detection resistor 40a, the configuration of the second switch Sz may also be changed between the second connection point P2 and the vehicle-side grounding member FG.

[0097] In the above embodiment, if Fig.16 As shown, the switch Si and the switch Sz may be connected between the positive-electrode power supply path L1 and the vehicle-side ground FG, and the arrangement of the first switch Si and the second switch Sz may be changed.

[0098] like Fig.16 As shown, the first A detection resistor 30a of this modified example is connected to the positive side power supply path L1 side, the first B detection resistor 30b is connected to the vehicle side grounding member FG side, the second A detection resistor 40a is connected to the positive side power supply path L1 side, and the second B detection resistor 40b is connected to the vehicle side grounding member FG side. The first switch Si is connected between the first connection point P1 and the first A detection resistor 30a, and is configured to be able to switch the power-on state and the power-off state between the first connection point P1 and the first A detection resistor 30a. Moreover, the second switch Sz is connected between the second connection point P2 and the second A detection resistor 40a, and is configured to be able to switch the power-on state and the power-off state between the second connection point P2 and the second A detection resistor 40a. In addition, the control device 70 is connected to the vehicle side grounding member, and measures the input signal using the vehicle side grounding member FG as a reference for the potential. At this time, the control device 70 does not need a differential amplifier circuit. In addition, if the configuration is such that the energization state between the first connection point P1 and the first A detection resistor 30a can be switched, the configuration of the first switch Si can be changed between the first connection point P1 and the positive-side power supply path L1. Similarly, if the configuration is such that the energization state between the second connection point P2 and the second A detection resistor 40a can be switched, the configuration of the second switch Sz can be changed between the second connection point P2 and the positive-side power supply path L1.

[0099] In the first embodiment, the fourth embodiment, or their variations, the first switch Si may be omitted if the resistance value R1 of the first voltage divider circuit 30 can be designed to be equal to or greater than the insulation resistance Rp, Rn and the vehicle insulation is not affected. In this case, the switch portion corresponds to the second switch Sz. If configured in this way, since the first voltage divider circuit 30 is always in the energized state, it is no longer possible to correct the circuit error by making the first voltage divider circuit 30 in the energized and disconnected state as described in the second and third embodiments. However, since the first switch Si is omitted, leakage detection and characteristic determination can be achieved at a low cost.

[0100] Hereinafter, characteristic structures extracted from the above-mentioned embodiments will be described. [Structure 1] A leakage detection device, in a leakage detection device (20) for detecting leakage between a power path (L1, L2) connected to a terminal of a battery (10) and a grounding member (FG), comprises: A first voltage divider circuit (30) having one end connected to the power supply path side and the other end connected to the grounding member side, thereby being in an energized state; A second voltage divider circuit (40) having one end connected to the power supply path side and the other end connected to the grounding member side, and connected in parallel with the first voltage divider circuit, thereby being in an energized state; a switch unit (Sz) configured to switch between a power-on state and a power-off state of the second voltage dividing circuit; and A control unit (70) controls the switch unit, inputs a voltage division value of the first voltage division circuit, and detects leakage; The control unit is configured to receive the voltage division values ​​from the first voltage division circuit and the second voltage division circuit, and implement: a first input step of controlling the switch section to switch the second voltage dividing circuit to an on state, inputting a first voltage dividing value from the first voltage dividing circuit, and inputting a second voltage dividing value from the second voltage dividing circuit; a second input step, after the first input step, controlling the switch unit to switch the second voltage divider circuit to a power-on / off state, and inputting a third voltage divider value from the first voltage divider circuit; a characteristic determination step of determining whether the first voltage dividing circuit and the second voltage dividing circuit are free of abnormality based on the first voltage dividing value and the second voltage dividing value; and A leakage detection step is performed to detect leakage based on the first divided voltage value and the third divided voltage value. [Structure 2] According to the leakage detection device described in Structure 1, the switch section is configured to be able to switch the energized state and the energized disconnected state of the first voltage divider circuit, and is configured to be able to switch the energized state and the energized disconnected state of the second voltage divider circuit. The control unit executes: an initial value acquisition step of controlling the switch unit to switch the first voltage divider circuit and the second voltage divider circuit to a power-on / off state, acquiring a first initial value based on a signal input from the first voltage divider circuit in the power-on / off state, and acquiring a second initial value based on a signal input from the second voltage divider circuit in the power-on / off state; and A correction step, which corrects the deviation caused by the circuit characteristics of the first voltage divider circuit based on the first initial value obtained in the initial value acquisition step, and corrects the deviation caused by the circuit characteristics of the second voltage divider circuit based on the second initial value obtained in the initial value acquisition step. [Structure 3] According to the leakage detection device described in structure 2, when either the first voltage divider circuit or the second voltage divider circuit is in a powered-on state, the control unit inputs a voltage divider value from the first voltage divider circuit or the second voltage divider circuit in a powered-on state via a heavy filter circuit (202) with a large time constant, On the other hand, when either the first voltage divider circuit or the second voltage divider circuit is in the power-on / off state, a signal from the first voltage divider circuit or the second voltage divider circuit in the power-on / off state is input via a light filter circuit (204) with a small time constant. [Structure 4] According to the leakage detection device recorded in any one of structures 1 to 3, the control unit, in the leakage detection step, calculates the value of the insulation resistance using the voltage across the first voltage divider circuit calculated based on the first voltage divider value, the voltage across the first voltage divider circuit calculated based on the third voltage divider value, the value of the detection resistor of the first voltage divider circuit, and the value of the detection resistor of the second voltage divider circuit, and detects leakage based on the value of the insulation resistance. [Structure 5] According to the leakage detection device recorded in Structure 4, in the leakage detection step, the control unit detects leakage without calculating the value of the insulation resistance when the voltage across the first voltage divider circuit calculated according to the first voltage divider value is below a first threshold value, or when the voltage across the first voltage divider circuit calculated according to the third voltage divider value is below a second threshold value. [Structure 6] According to the leakage detection device described in any one of Structures 1 to 5, the switch unit includes a first switch (Si) and a second switch (Sz) connected in series with the first switch, One end of the first voltage divider circuit is connected to the negative power supply path, and the other end is connected between the first switch and the second switch, and is connected in series with the grounding member via the first switch. One end of the second voltage divider circuit is connected to the negative power supply path, and the other end is connected in series to one end of the second switch that is not connected to the first switch, and is connected in series to the grounding member via the second switch and the first switch. [Structure 7] According to the leakage detection device described in any one of Structures 1 to 5, the switch unit includes a first switch (Si) and a second switch (Sz) connected in series with the first switch, One end of the first voltage divider circuit is connected to the grounding member, and the other end is connected between the first switch and the second switch, and is connected in series with the positive power supply path via the first switch. One end of the second voltage divider circuit is connected to the grounding member, and the other end is connected in series to one end of the second switch that is not connected to the first switch, and is connected in series to the positive power supply path via the second switch and the first switch. [Structure 8] According to the leakage detection device described in any one of structures 1 to 5, the switch unit includes a first switch (Si) and a second switch (Sz), The first voltage divider circuit comprises a first A detection resistor (30a) and a first B detection resistor (30b) connected in series with the first A detection resistor, the first A detection resistor being connected to the grounding member side, and the first B detection resistor being connected to the negative side power supply path (L2, SG) side connected to the negative side terminal of the battery, The second voltage divider circuit comprises a second A detection resistor (40a) and a second B detection resistor (40b) connected in series with the second A detection resistor, the second A detection resistor being connected to the grounding member side, and the second B detection resistor being connected to the negative power supply path side. The control unit is connected to the negative-side power supply path, and is configured to measure an input signal using the negative-side power supply path as a reference for potential, and input a signal from the first voltage divider circuit via a first output line (L11), one end of the first output line is connected to a first connection point (P1) between the first A detection resistor and the first B detection resistor, and the other end is connected to the control unit, and input a signal from the second voltage divider circuit via a second output line (L12), one end of the second output line is connected to a second connection point (P2) between the second A detection resistor and the second B detection resistor, and the other end is connected to the control unit, The first switch is connected between the first connection point and the grounding member, and is configured to switch between a power-on state and a power-off state between the first connection point and the first A detection resistor. The second switch is connected between the second connection point and the grounding member, and is configured to be able to switch between a power-on state and a power-off state between the second connection point and the second A detection resistor. [Structure 9] According to the leakage detection device described in any one of structures 1 to 5, the switch unit includes a first switch (Si) and a second switch (Sz), The first voltage divider circuit comprises a first A detection resistor (30a) and a first B detection resistor (30b) connected in series with the first A detection resistor, the first A detection resistor being connected to a positive-side power supply path (L1) connected to a positive-side terminal of the battery, and the first B detection resistor being connected to a grounding member. The second voltage divider circuit comprises a second A detection resistor (40a) and a second B detection resistor (40b) connected in series with the second A detection resistor, the second A detection resistor being connected to the positive-side power supply path, and the second B detection resistor being connected to the grounding member side. The control unit is connected to the grounding member and is configured to measure an input signal using the grounding member as a reference for potential, and input a signal from the first voltage divider circuit via a first output line (L11), one end of the first output line is connected to a first connection point (P1) between the first A detection resistor and the first B detection resistor, and the other end is connected to the control unit, and input a signal from the second voltage divider circuit via a second output line (L12), one end of the second output line is connected to a second connection point (P2) between the second A detection resistor and the second B detection resistor, and the other end is connected to the control unit, The first switch is connected between the first connection point and the positive-side power supply path, and is configured to be able to switch between a power-on state and a power-off state between the first connection point and the first A detection resistor. The second switch is connected between the second connection point and the positive-side power supply path, and is configured to be able to switch between a energized state and a deenergized state between the second connection point and the second A detection resistor.

[0101] Although the present disclosure is described based on the embodiments, it should be understood that the present disclosure is not limited to the above-mentioned embodiments and structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and methods, and other combinations and methods containing only one element, above or below them, also belong to the scope and thought range of the present disclosure.

Claims

1. A leakage detection device, which is a leakage detection device (20) for detecting leakage between a power path (L1, L2) connected to a terminal of a battery (10) and a grounding member (FG), comprising: A first voltage divider circuit (30) having one end connected to the power supply path side and the other end connected to the grounding member side, thereby being in an energized state; A second voltage divider circuit (40) having one end connected to the power supply path side and the other end connected to the grounding member side, and connected in parallel with the first voltage divider circuit, thereby being in an energized state; a switch unit (Sz, 50) configured to switch between a power-on state and a power-off state of the second voltage dividing circuit; and A control unit (70) controls the switch unit, inputs a voltage division value of the first voltage division circuit, and detects leakage; The control unit is configured to receive the voltage division values ​​from the first voltage division circuit and the second voltage division circuit, and implement: a first input step, in which the switch section is controlled to switch the second voltage divider circuit to an on state, a first voltage divider value from the first voltage divider circuit is input, and a second voltage divider value from the second voltage divider circuit is input; a second input step, after the first input step, controlling the switch unit to switch the second voltage divider circuit to a power-on / off state, and inputting a third voltage divider value from the first voltage divider circuit; a characteristic determination step, in which it is determined whether the first voltage division circuit and the second voltage division circuit are free of abnormality based on the first voltage division value and the second voltage division value; as well as A leakage detection step is performed to detect leakage based on the first divided voltage value and the third divided voltage value.

2. The leakage detection device according to claim 1, characterized in that: The switch unit is configured to be able to switch between a power-on state and a power-off state of the first voltage dividing circuit, and is configured to be able to switch between a power-on state and a power-off state of the second voltage dividing circuit. The control unit executes: an initial value acquisition step, in which the switch unit is controlled to switch the first voltage divider circuit and the second voltage divider circuit to a power-on / off state, a first initial value is acquired based on a signal input from the first voltage divider circuit in the power-on / off state, and a second initial value is acquired based on a signal input from the second voltage divider circuit in the power-on / off state; as well as A correction step, in which the deviation caused by the circuit characteristics of the first voltage divider circuit is corrected based on the first initial value obtained in the initial value acquisition step, and the deviation caused by the circuit characteristics of the second voltage divider circuit is corrected based on the second initial value obtained in the initial value acquisition step.

3. The leakage detection device according to claim 2, characterized in that: When either the first voltage divider circuit or the second voltage divider circuit is in a power-on state, the control unit inputs a voltage divider value from the first voltage divider circuit or the second voltage divider circuit in a power-on state via a heavy filter circuit (202) having a large time constant. On the other hand, when either the first voltage divider circuit or the second voltage divider circuit is in a power-off state, the control unit inputs a signal from the first voltage divider circuit or the second voltage divider circuit in a power-off state via a light filter circuit (204) having a small time constant.

4. The leakage detection device according to claim 1, characterized in that: In the leakage detection step, the control unit calculates the value of the insulation resistance using the detection voltage of the first voltage divider circuit calculated based on the first voltage divider value, the detection voltage of the first voltage divider circuit calculated based on the third voltage divider value, the value of the detection resistor of the first voltage divider circuit, and the value of the detection resistor of the second voltage divider circuit, and detects leakage based on the value of the insulation resistance.

5. The leakage detection device according to claim 4, characterized in that: In the leakage detection step, the control unit detects leakage without calculating the value of insulation resistance when the detection voltage of the first voltage divider circuit calculated based on the first voltage divider value is less than a first threshold value, or when the detection voltage of the first voltage divider circuit calculated based on the third voltage divider value is less than a second threshold value.

6. The leakage detection device according to claim 2 or 4, characterized in that: The switch unit includes a first switch (Si) and a second switch (Sz) connected in series with the first switch, One end of the first voltage divider circuit is connected to the negative power supply path, and the other end is connected between the first switch and the second switch, and is connected in series with the grounding member via the first switch. One end of the second voltage divider circuit is connected to the negative power supply path, and the other end is connected in series to one end of the second switch that is not connected to the first switch, and is connected in series to the grounding member via the second switch and the first switch.

7. The leakage detection device according to claim 2 or 4, characterized in that: The switch unit includes a first switch (Si) and a second switch (Sz) connected in series with the first switch, One end of the first voltage divider circuit is connected to the grounding member, and the other end is connected between the first switch and the second switch, and is connected in series with the positive power supply path via the first switch. One end of the second voltage divider circuit is connected to the grounding member, and the other end is connected in series to one end of the second switch that is not connected to the first switch, and is connected in series to the positive power supply path via the second switch and the first switch.

8. The leakage detection device according to claim 2 or 4, characterized in that: The switch unit includes a first switch (Si) and a second switch (Sz), The first voltage divider circuit comprises a first A detection resistor (30a) and a first B detection resistor (30b) connected in series with the first A detection resistor, the first A detection resistor being connected to the grounding member side, and the first B detection resistor being connected to the negative side power supply path (L2, SG) side connected to the negative side terminal of the battery, The second voltage divider circuit comprises a second A detection resistor (40a) and a second B detection resistor (40b) connected in series with the second A detection resistor, the second A detection resistor being connected to the grounding member side, and the second B detection resistor being connected to the negative power supply path side. The control unit is connected to the negative-side power supply path, and is configured to measure an input signal using the negative-side power supply path as a reference for potential, and input a signal from the first voltage divider circuit via a first output line (L11), one end of the first output line is connected to a first connection point (P1) between the first A detection resistor and the first B detection resistor, and the other end is connected to the control unit, and input a signal from the second voltage divider circuit via a second output line (L12), one end of the second output line is connected to a second connection point (P2) between the second A detection resistor and the second B detection resistor, and the other end is connected to the control unit, The first switch is connected between the first connection point and the grounding member, and is configured to switch between a power-on state and a power-off state between the first connection point and the first A detection resistor. The second switch is connected between the second connection point and the grounding member, and is configured to be able to switch between a power-on state and a power-off state between the second connection point and the second A detection resistor.

9. The leakage detection device according to claim 2 or 4, characterized in that: The switch unit includes a first switch (Si) and a second switch (Sz), The first voltage divider circuit comprises a first A detection resistor (30a) and a first B detection resistor (30b) connected in series with the first A detection resistor, the first A detection resistor being connected to a positive-side power supply path (L1) connected to a positive-side terminal of the battery, and the first B detection resistor being connected to a grounding member. The second voltage divider circuit comprises a second A detection resistor (40a) and a second B detection resistor (40b) connected in series with the second A detection resistor, the second A detection resistor being connected to the positive-side power supply path, and the second B detection resistor being connected to the grounding member side. The control unit is connected to the grounding member and is configured to measure an input signal using the grounding member as a reference for potential, and input a signal from the first voltage divider circuit via a first output line (L11), one end of the first output line is connected to a first connection point (P1) between the first A detection resistor and the first B detection resistor, and the other end is connected to the control unit, and input a signal from the second voltage divider circuit via a second output line (L12), one end of the second output line is connected to a second connection point (P2) between the second A detection resistor and the second B detection resistor, and the other end is connected to the control unit, The first switch is connected between the first connection point and the positive-side power supply path, and is configured to be able to switch between a power-on state and a power-off state between the first connection point and the first A detection resistor. The second switch is connected between the second connection point and the positive-side power supply path, and is configured to be able to switch between a energized state and a deenergized state between the second connection point and the second A detection resistor.

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