Electric leakage detection device

Abstract

An electric leakage detection device (20) includes: a first voltage division circuit (30); a resistance circuit (40) connected in parallel to the first voltage division circuit; a switch unit (S2) configured so as to be capable of switching between a power-on state and a power-off state of the resistance circuit; and a control unit (70) that performs switching control on the switch unit, inputs the first voltage division values (Vns1, Vns2) of the first voltage division circuit, calculates insulation resistance on the basis of the input first voltage division values, and detects electric leakage. The first voltage division circuit has a range changing circuit (60) that changes the voltage division ratio of the first voltage division circuit, and the control unit changes the voltage division ratio of the first voltage division circuit by means of the range changing circuit so that the first voltage division value becomes large when the input first voltage division value (Vns01, Vns02) is less than a threshold value (Vth).

Description

Citation of related applications

[0001] This application is based on Japanese Patent Application No. 2022-169414 filed on October 21, 2022 and Japanese Patent Application No. 2023-012215 filed on January 30, 2023, and the contents thereof are cited herein. 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 grounding member, frame grounding member) in order 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 insulation resistance detection circuit described in Patent Document 1 is configured to detect insulation resistance and can detect a decrease in detection accuracy due to aging degradation 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] In the insulation resistance detection circuit of Patent Document 1, when the insulation resistance Rn (insulation resistance on the negative electrode side) to the ground between the grounding member that determines the reference potential of the high voltage circuit and the vehicle-side grounding member becomes smaller, the detection voltage becomes smaller. Furthermore, when the detection voltage becomes too small, the detection error becomes larger at the resolution of the insulation resistance detection circuit, and there is a possibility that leakage cannot be properly determined.

[0007] The present disclosure is proposed to solve the above-mentioned technical problems, and its object is to provide a leakage detection device capable of performing leakage detection with high accuracy.

[0008] The leakage detection device for solving the above technical problem detects leakage between a power path connected to a terminal of a battery and a grounding member, and the leakage detection device comprises: A first 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; a resistance circuit, one end of which is connected to the power supply path side, the other end of which is connected to the grounding member side, and which is connected in parallel with the first voltage divider circuit; a switch unit configured to switch between an energized state and an energized disconnected state of the resistor circuit; and a control unit, wherein the control unit controls the switching of the switch unit, inputs a first voltage division value of the first voltage division circuit, and calculates the insulation resistance and detects leakage according to the input first voltage division value, The first voltage dividing circuit has a range changing circuit for changing the voltage dividing ratio of the first voltage dividing circuit. When the input first divided voltage value of the first divided voltage circuit is smaller than a threshold value, the control unit changes the voltage division ratio of the first divided voltage circuit through the range change circuit so as to increase the first divided voltage value.

[0009] According to this configuration, when the first voltage division value is less than the threshold value, the control unit changes the voltage division ratio to increase the first voltage division value, so that even if the resolution of the control unit is not changed, the resolution can be substantially reduced. Therefore, even if the insulation resistance is reduced, the detection error can be reduced, thereby performing leakage detection with high accuracy.

[0010] The leakage detection device for solving the above technical problem detects leakage between the power path on the positive side connected to the positive terminal of the battery and the grounding member, and leakage between the power path on the negative side connected to the negative terminal of the battery and the grounding member, and the leakage detection device includes: A first voltage divider circuit, one end of which is connected to the first power path as either the positive power path or the negative power path, and the other end of which is connected to the grounding member; a resistance circuit, one end of which is connected to the first power supply path side, the other end of which is connected to the grounding member side, and which is connected in parallel with the first voltage divider circuit; a switch unit configured to switch between an energized state and an energized disconnected state of the resistor circuit; a control unit that controls switching of the switch unit, inputs a first voltage-dividing value of the first voltage-dividing circuit, and calculates insulation resistance and detects leakage according to the input first voltage-dividing value; and A resistor, one end of which is connected to a second power path different from the first power path among the power path on the positive electrode side and the power path on the negative electrode side, and the other end of which is connected to the grounding member side.

[0011] Thus, even if the insulation resistance increases, its influence can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 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 flowchart of the switching process. Figure 4 It is a flowchart of the calculation process. Figure 5 This is a flowchart of the characteristic determination process. Figure 6 This is a flowchart of the insulation resistance calculation process. Figure 7 It is a diagram showing the calculation method of various values. Figure 8 is a timing chart showing detection timing. Fig. 9 is a timing chart showing detection timing. Fig.10 It is a graph showing the detection accuracy in the comparative example. Fig.11 is a graph showing the detection accuracy in the present disclosure. Fig.12 It is a structural diagram of a vehicle-mounted power supply system according to a modified example. Fig.13 It is a diagram showing a calculation method of various values ​​in a modification example. Fig.14 It is a structural diagram of a vehicle-mounted power supply system according to a modified example. Fig.15 It is a structural diagram of a vehicle-mounted power supply system according to a modified example. Fig.16 It is a structural diagram of a vehicle-mounted power supply system according to a modified example. Fig.17 It is a diagram showing a calculation method of various values ​​in a modification example. Fig.18 This is a flowchart of the leakage detection process in the modification example. Fig.19 It is a diagram showing a calculation method of various values ​​in a modification example. Fig. 20 It is a configuration diagram of a vehicle-mounted power supply system according to a second embodiment. Fig.21 It is a diagram showing the detection range and the on and off states of the switch. Fig. 22 This is a flowchart of the leakage detection process according to the second embodiment. Fig.23 is a flowchart of the range switching process. Fig.24 is a flow chart of the detection process. Fig.25 This is a flowchart of the insulation resistance calculation process according to the second embodiment. Fig.26 It is a diagram showing a calculation method of various values ​​in the second embodiment. Fig. 27 is a timing chart showing the switching of the detection range. DETAILED DESCRIPTION

[0013] 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.

[0014] (First Embodiment) Figure 1 The vehicle power supply system 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.

[0015] 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.

[0016] 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 a frame grounding member. 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.

[0017] 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.

[0018] 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, whether there is leakage (ground fault).

[0019] The leakage detection device 20 is described in detail. The leakage detection device 20 includes: a first voltage dividing circuit 30; a second voltage dividing circuit 40 connected in parallel to the first voltage dividing circuit 30; a first switch S1; a second switch S2; and a control device 70 as a control unit for detecting leakage.

[0020] The first voltage dividing circuit 30 is connected between the vehicle ground FG and the negative power supply path L2, and divides the voltage between the negative power supply path L2 and the vehicle ground FG (the voltage across the first voltage dividing circuit 30) by a voltage dividing ratio α or a voltage dividing ratio α′.

[0021] Describing its structure in detail, the first voltage divider circuit 30 includes a first A detection resistor Rs1, a first B detection resistor Rk1', and a first C detection resistor Rk1. The first C detection resistor Rk1 is connected in parallel with the first B detection resistor Rk1'. The parallel connection of the first C detection resistor Rk1 and the first B detection resistor Rk1' is connected in series with the first A detection resistor Rs1.

[0022] The first A detection resistor Rs1 is connected to the vehicle side grounding member FG side, and the parallel connection body composed of the first B detection resistor Rk1' and the first C detection resistor Rk1 is connected to the negative side power supply path L2 side. One end of the first output line L11 is connected to the first connection point P1 between the first A detection resistor Rs1 and the parallel connection body composed of the first B detection resistor Rk1' and the first C detection resistor Rk1. The voltage signal (first divided voltage value) from the first voltage divider circuit 30 is output via the first output line L11. In addition, a third switch S3 is connected in series with the first C detection resistor Rk1, and the third switch S3 is configured to switch between the energized state and the energized cutoff state. When the third switch S3 is turned on, the first C detection resistor Rk1 is energized, and the voltage division ratio of the first voltage divider circuit 30 becomes α. When the third switch S3 is turned off, the first C detection resistor Rk1 is energized and the voltage division ratio of the first voltage divider circuit 30 becomes α'.

[0024] The third switch S3 is controlled to be turned on and off by the control device 70. Moreover, the resistance value of the first B detection resistor Rk1' is much larger than the resistance value of the first C detection resistor Rk1, for example, a value of about 10 times. Therefore, the voltage division ratio α' is larger than the voltage division ratio α, and when the third switch S3 is disconnected, the detection voltage becomes larger. For example, if the resistance value of the first B detection resistor Rk1' is 10 times that of the first C detection resistor Rk1, the voltage division value (voltage signal) is also approximately 10 times. That is, under normal circumstances, when the detection is within the range of 0 to V1, if the third switch S3 is switched to disconnect, it becomes detected within the range of 0 to V1 / 10. In this embodiment, the first B detection resistor Rk1' and the third switch S3 are equivalent to the range change circuit 60.

[0025] The second voltage divider circuit 40 is connected between the negative side power supply path L2 and the vehicle side grounding member FG, and divides the voltage between the negative side power supply path L2 and the vehicle side grounding member FG (the voltage at both ends of the second voltage divider circuit 40) with a voltage divider ratio β. The second voltage divider circuit 40 is equivalent to a resistance circuit. In addition, in the first embodiment, the negative side power supply path L2 is equivalent to the first power supply path, and the positive side power supply path L1 is equivalent to the second power supply path. The structure of the second voltage divider circuit 40 is described in detail. The second voltage divider circuit 40 has a second A detection resistor Rs2 and a second B detection resistor Rk2, and is composed of a series connection body formed by connecting them in series. The second A detection resistor Rs2 is connected to the vehicle side grounding member FG side, and the second B detection resistor Rk2 is connected to the negative side power supply path L2 side. The second connection point P2 between the second A detection resistor Rs2 and the second B detection resistor Rk2 is connected to one end of the second output line L12, and the voltage signal (second voltage divider value) from the second voltage divider circuit 40 is output via the second output line L12.

[0026] Next, the first switch S1 and the second switch S2 are described. The first switch S1 and the second switch S2 are controlled to be turned on and off by the control device 70. The first switch S1 is configured to be able to switch between the energized state and the energized disconnected state of the first voltage divider circuit 30. In addition, the second switch S2 is configured to be able to switch between the energized state and the energized disconnected state of the second voltage divider circuit 40.

[0027] In detail, the first switch S1 is connected between the first connection point P1 and the first A detection resistor Rs1, 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 Rs1. The second switch S2 is connected between the second connection point P2 and the second A detection resistor Rs2, 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 Rs2. The second switch S2 is equivalent to a switch unit.

[0028] The control device 70 is mainly composed of a microcomputer including 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 the function of controlling the on / off state of the first switch S1 and the second switch S2, the function of controlling the on / off state of the third switch S3, the function of detecting leakage, etc. In addition, a switch control unit having the function of controlling the on / off state of various switches can be provided outside the control device 70 to cooperate with the control device 70 to detect leakage. In addition, the control device 70 estimates the values ​​of the insulation resistances Rp and Rn and detects leakage based on the voltage signal (first voltage division value) input from the first voltage division circuit 30. However, when the insulation resistance Rn becomes smaller, the first voltage division value also becomes smaller. Moreover, if the first voltage division value becomes too small, the detection error becomes larger at the resolution of the control device 70, and it is possible that the leakage cannot be determined normally. Therefore, in order to prevent the first voltage division value from becoming too small, a range change circuit 60 is provided, and is configured to be able to change the first voltage division ratio.

[0030] The following is based on Figure 2 to Figure 6 The leakage detection process is described in detail. Figure 7 , the calculation formulas and characteristic diagnosis formulas of the resistance values ​​R1 and R1' of the first voltage divider circuit 30, the resistance value R2 of the second voltage divider circuit 40, the voltage dividing ratios α and α' of the first voltage divider circuit 30, the voltage dividing ratio β of the second voltage divider circuit 40, the insulation resistances Rp, Rn, and Rp / / Rn are shown.

[0031] exist Figure 7 In FIG. 1 , the left side shows the calculation method of each value when the third switch S3 is turned on, and the right side shows the calculation method of each value when the third switch S3 is turned off. That is, the resistance value R1 of the first voltage divider circuit 30 is the resistance value when the third switch S3 is turned on, and the resistance value R1' is the resistance value when it is turned off. Similarly, the voltage division ratio α of the first voltage divider circuit 30 is the voltage division ratio when the third switch S3 is turned on, and the voltage division ratio α' is the voltage division ratio when it is turned off.

[0032] The characteristic diagnosis formula is a formula used when determining whether the characteristics of the first voltage divider circuit 30 and the second voltage divider circuit 40 are abnormal. The characteristic determination refers to, for example, determining whether the values ​​of the detection resistors Rs1, Rs2, Rk1, Rk1', and Rk2 have changed due to aging, poor contact, foreign matter mixing, disconnection, short circuit, etc.

[0033] In addition, the resistance value of the first A detection resistor Rs1 is "Rs1", the resistance value of the first B detection resistor Rk1' is "Rk1", and the resistance value of the first C detection resistor Rk1 is "Rk1". Similarly, the resistance value of the second A detection resistor Rs2 is "Rs2", and the resistance value of the second B detection resistor Rk2 is "Rk2". In addition, the terminal voltage of the battery pack 10 is "V1".

[0034] In addition, the voltage across the insulation resistor Rn is equivalent to "Vni", and the voltage across the insulation resistor Rn when the first switch S1 and the second switch S2 are turned on is equivalent to "Vn1". In addition, the voltage across the insulation resistor Rn when the first switch S1 is turned on and the second switch S2 is turned off is equivalent to "Vn2".

[0035] In addition, the first voltage division value from the first voltage division circuit 30 corresponds to "Vnsi", and the first voltage division value from the first voltage division circuit 30 when the first switch S1 and the second switch S2 are turned on corresponds to "Vns1". In addition, the first voltage division value from the first voltage division circuit 30 when the first switch S1 is turned on and the second switch S2 is turned off corresponds to "Vns2". In addition, the first voltage division value from the second voltage division circuit 40 when the first switch S1 and the second switch S2 are turned on corresponds to "Vrs1".

[0036] Figure 2 The leakage detection process shown is implemented by the control device 70 at a predetermined period (for example, every several tens of milliseconds). When implementing the leakage detection process, first, the control device 70 turns on all the first switch S1 to the third switch S3 (step S101). As a result, the first voltage divider circuit 30 and the second voltage divider circuit 40 are both powered on, 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. In addition, in the first voltage divider circuit 30, the first B detection resistor Rk1' and the first C detection resistor Rk1 are both powered on, and the voltage divider ratio of the first voltage divider circuit 30 becomes the voltage divider ratio α.

[0037] Then, the control device 70 performs the switching process of the third switch S3 after a predetermined time has passed (step S102). Figure 3 To illustrate the switching process. In addition, in the switching process of step S102, i is replaced by 1. For example, Figure 3 Replace Vns0i with Vns01.

[0038] In the switching process, the control device 70 inputs (detects) the first divided voltage value Vns0i from the first divided voltage circuit 30 (step S201). When the third switch S3 is on, the first divided voltage value Vns0i=α×Vni, and when it is off, the first divided voltage value Vns0i=α′×Vni. Next, the control device 70 determines whether the third switch S3 is turned on (step S202). If the determination result of step S202 is positive, the control device 70 determines whether the detected first voltage division value Vns0i is less than the threshold value Vth (step S203). The threshold value Vth is an arbitrary value, which is set according to the resolution of the control device 70, the required detection accuracy, etc.

[0040] If the determination result of step S203 is positive, the control device 70 switches the third switch S3 to off (step S204). As a result, in the first voltage divider circuit 30, the first C detection resistor Rk1 becomes energized and cut-off, and the voltage divider ratio of the first voltage divider circuit 30 becomes the voltage divider ratio α'. If the determination result of step S203 is negative, the control device 70 directly ends the switching process and transfers to the process of step S103.

[0041] On the other hand, if the determination result of step S202 is negative, the control device 70 determines whether the detected first divided voltage value Vns0i is greater than the limit value Vmax (step S205). The limit value Vmax is an arbitrary value and is set according to the resolution, withstand voltage, detection accuracy, etc. of the control device 70.

[0042] If the determination result of step S205 is positive, the control device 70 switches the third switch S3 to on (step S206), and ends the switching process. As a result, in the first voltage divider circuit 30, the first C detection resistor Rk1 becomes energized, and the voltage division ratio of the first voltage divider circuit 30 becomes the voltage division ratio α. If the determination result of step S205 is negative, the control device 70 directly ends the switching process and transfers to the process of step S103.

[0043] like Figure 2 As shown, after the switching process of step S102 is completed, at the time when the prescribed time has passed, the control device 70 inputs (detects) the first voltage division value Vns1 from the first voltage division circuit 30, and inputs (detects) the second voltage division value Vrs1 from the second voltage division circuit 40 (step S103). In addition, when the third switch S3 is turned on, the first voltage division value Vns1 = α × Vn1, and when it is turned off, the first voltage division value Vns1 = α' × Vn1. In addition, the second voltage division value Vrs1 = β × Vn1.

[0044] Next, the control device 70 performs a calculation process of Vn1 (step S104). Figure 4 To illustrate the calculation process. In addition, in the calculation process of step S104, i is replaced by 1. For example, Figure 4 Vni is replaced by Vn1, and Vnsi is replaced by Vns1.

[0045] In the calculation process, the control device 70 determines whether the third switch S3 is turned on (step S301). If the determination result of step S301 is positive, the control device 70 calculates Vnsi / α, calculates Vni (step S302), and ends the calculation process. On the other hand, if the determination result of step S301 is negative, the control device 70 calculates Vnsi / α', calculates Vni (step S303), and ends the calculation process.

[0046] like Figure 2 As shown, after the calculation process of step S104 is completed, the control device 70 implements the characteristic determination process (step S105). Figure 5 The characteristic determination process will be described. In the characteristic determination process of step S105, the control device 70 determines whether the third switch S3 is turned on (step S401). If the determination result of step S401 is positive, the control device 70 Figure 7 It is determined whether the result of the mathematical formula (1) shown is approximately 1 (step S402). Figure 7 As shown, it is determined whether the characteristic diagnosis formula (the value of (Vns 1 / α)×(β / Vrs1) in the mathematical formula (1)) when the third switch S3 is turned on is within a prescribed range close to 1. The prescribed range is set in consideration of the calculation accuracy. If the value is within the 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.

[0048] On the other hand, if the determination result of step S401 is negative, the control device 70 performs the following operations similarly to step S402. Figure 7 It is determined whether the result of the mathematical formula (2) shown is approximately 1 (step S403). Figure 7 As shown, it is determined whether the value (Vns1 / α')×(β / Vrs 1) of the characteristic diagnosis formula (Equation (2)) when the third switch S3 is turned off is within a prescribed range close to 1. The prescribed range is set in consideration of calculation accuracy. If the value is within the 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. If the determination result of step S402 or step S403 is positive, it is determined that there is no characteristic abnormality, and the control device 70 ends the characteristic determination process and transfers to the next step S106. On the other hand, if the determination result of step S402 or step S403 is negative, it is determined that there is a characteristic abnormality in the first voltage divider circuit 30 or the second voltage divider circuit 40, and the control device 70 interrupts the leakage detection process and implements a process for dealing with the abnormality of the voltage divider circuit 30, 40 (step S404). The process for dealing with the abnormality of the voltage divider circuit 30, 40 refers to, for example, a process for notifying the external device of the abnormality and warning that leakage detection cannot be performed.

[0050] like Figure 2 As shown in FIG. 1 , after the characteristic determination process is normally completed, at the time when the predetermined time has passed, the control device 70 switches the second switch S2 to off (step S106). Thereafter, at the time when the predetermined time has passed, the control device 70 performs the switching process of the third switch S3 (step S107). In addition, the switching process of step S107 is performed after the switching process of step S102 and Figure 3 In the description of , if i=2 is replaced, it is the same as above. For example, if Vns0i is replaced by Vns02, it is the same as above. Therefore, the description is omitted here.

[0051] like Figure 2 As shown, after the switching process of step S107 is completed, at the time when the predetermined time has passed, the control device 70 inputs (detects) the first divided voltage value Vns2 from the first divided voltage circuit 30 (step S108). In addition, when the third switch S3 is turned on, the first divided voltage value Vns2 = α × Vn2, and when it is turned off, the first divided voltage value Vns2 = α' × Vn2.

[0052] Next, the control device 70 performs a calculation process of Vn2 (step S109). The calculation process of step S109 is performed after the calculation process of step S104 and Figure 4 In the description of , if i=2 is replaced, it is the same as above. For example, if Vnsi is replaced by Vns2, and Vni is replaced by Vn2, it is the same as above. Therefore, the description is omitted here.

[0053] When the calculation process of step S109 is finished, Figure 2 As shown in FIG. 1 , the control device 70 performs an insulation resistance calculation process to calculate the insulation resistance (step S110 ). Figure 6 The insulation resistance calculation process will be described below.

[0054] In the insulation resistance calculation process of step S110, the control device 70 determines whether the third switch S3 is turned on (step S501). If the determination result of step S501 is positive, the control device 70 calculates the insulation resistance based on Vn1 and Vn2 calculated in steps S104 and S109 (step S502). Figure 7 The mathematical formula (3) described above is a synthetic calculation formula of the insulation resistances Rp and Rn when the third switch S3 is turned on to calculate Rp / / Rn. Figure 7 The insulation resistances Rp and Rn are obtained by using the equations (5) and (7).

[0055] On the other hand, if the determination result of step S501 is negative, the control device 70 calculates the insulation resistance based on Vn1 and Vn2 calculated in steps S104 and S109 (step S503). Figure 7 The mathematical formula (4) described above is a synthetic calculation formula of the insulation resistances Rp and Rn when the third switch S3 is turned off to calculate Rp / / Rn. Figure 7 The insulation resistances Rp and Rn are obtained by using the equations (6) and (7).

[0056] After the insulation resistance is calculated, the insulation resistance calculation process is terminated, and the control device 70 determines whether there is leakage based on the calculated insulation resistance (step S111). In step S111, for example, whether there is leakage is determined based on whether the calculated Rp / / Rn is within a predetermined normal range. In addition, when the insulation resistances Rp and Rn are calculated, leakage can also be determined based on whether they are below the determination thresholds Rp0 and Rn0, respectively.

[0057] When the determination result of step S111 is positive (when leakage is detected), the control device 70 implements a process for dealing with leakage (step S112) and ends the leakage detection process. The process for dealing with leakage refers to, for example, a process for notifying an external device of leakage and issuing a warning. On the other hand, when the determination result of step S112 is negative (when leakage is not detected), the control device 70 assumes that it is normal and ends the leakage detection process directly.

[0058] Next, refer to Figure 8 , Fig. 9 The detection timing of the divided voltage value and the switching timing of the first switch S1 to the third switch S3 will be described.

[0059] exist Figure 8In the description, it is assumed that the insulation resistances Rp and Rn are normal. When the first switch S1 to the third switch S3 are turned on (time point t1), 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 resistance Rn are connected in parallel between the negative side power supply path L2 and the vehicle side grounding member FG. In addition, in the first voltage divider circuit 30, the first B detection resistance Rk1' and the first C detection resistance Rk1 are both energized, and the voltage division ratio of the first voltage divider circuit 30 becomes the voltage division ratio α.

[0060] In order to stabilize the voltage division value, the control device 70 implements the switching process of the third switch S3 at the moment when the specified time has passed (time point t2). That is, the first voltage division value Vns01 from the first voltage division circuit 30 is input, and it is determined whether the first voltage division value Vns01 is less than the threshold value Vth. According to the premise, since the first voltage division value Vns01 is greater than the threshold value Vth, the third switch S3 is not disconnected (directly maintained on). The control device 70 inputs the first voltage division value Vns 1 at the moment when the specified time has passed (time point t3) thereafter, and implements the calculation process of Vn1. Here, since the third switch S3 is turned on, the control device 70 calculates Vns 1 / α and calculates Vn1.

[0061] Although not shown, the control device 70 receives the second divided voltage value Vrs1 from the second voltage dividing circuit 40 at time t3 and performs characteristic determination by determining whether (Vns1 / α)×(β / Vrs1) is approximately 1.

[0062] After calculating Vn1 and the like, the control device 70 turns off the second switch S2 at a time point (time point t4) after a predetermined time has passed. As a result, the first voltage divider circuit 30 is energized, and the second voltage divider circuit 40 is energized and disconnected. As a result, 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 grounding member FG. In addition, in the first voltage divider circuit 30, both the first B detection resistor Rk1' and the first C detection resistor Rk1 are energized, and the voltage division ratio of the first voltage divider circuit 30 becomes the voltage division ratio α.

[0063] In order to stabilize the voltage division value, the control device 70 implements the switching process of the third switch S3 at the moment when the specified time has passed (time point t5). That is, the first voltage division value Vns02 from the first voltage division circuit 30 is input, and it is determined whether the first voltage division value Vns02 is less than the threshold value Vth. According to the premise, since the first voltage division value Vns02 is above the threshold value Vth, the third switch S3 is not disconnected (directly maintained on). Then, the control device 70 inputs the first voltage division value Vns2 at the moment when the specified time has passed (time point t6) thereafter, and implements the calculation process of Vn2. Here, since the third switch S3 is turned on, the control device 70 calculates Vns2 / α and calculates Vn2.

[0064] Then, the control device 70 uses the calculated Vn1 and Vn2 to Figure 7 Rp / / Rn is calculated by the mathematical formula (1) shown in FIG. Then, it is determined that there is no leakage based on whether Rp / / Rn is within the normal range. Next, based on Fig. 9 For explanation. Fig. 9 In the description, it is assumed that a ground fault occurs in the insulation resistor Rn after all the first to third switches S1 to S3 are turned on (after time t1) and before the switching process of the third switch S3 is performed (before time t2).

[0066] When the first switch S1 to the third switch S3 are turned on (time point t1), 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. In addition, in the first voltage divider circuit 30, the first B detection resistor Rk1' and the first C detection resistor Rk1 are both energized, and the voltage division ratio of the first voltage divider circuit 30 becomes the voltage division ratio α.

[0067] In order to stabilize the voltage divider value, the control device 70 implements the switching process of the third switch S3 at the moment (time point t2) after the specified time has passed. That is, the first voltage divider value Vns01 from the first voltage divider circuit 30 is input, and it is determined whether the first voltage divider value Vns01 is less than the threshold value Vth. According to the premise, since the first voltage divider value Vns01 is smaller than the threshold value Vth, the third switch S3 is turned off. As a result, in the first voltage divider circuit 30, the first C detection resistor Rk1 becomes a power-on and power-off state, and the voltage divider ratio of the first voltage divider circuit 30 becomes a voltage divider ratio α'. Then, as shown in FIG. Fig. 9 As shown in FIG. 1 , the detected first voltage division value (detection voltage value) becomes larger (approximately 10 times). Fig. 9In FIG. 1 , the detection voltage when the voltage dividing ratio α of the first voltage dividing circuit 30 is maintained is shown by a dotted line.

[0068] After a predetermined time has passed, the control device 70 inputs the first voltage division value Vns1 and performs a calculation process of Vn1. Here, since the third switch S3 is off, the control device 70 calculates Vns1 / α' and calculates Vn1.

[0069] Although not shown, the control device 70 receives the second divided voltage value Vrs1 from the second voltage dividing circuit 40 at time t3 and determines whether (Vns1 / α′)×(β / Vrs1) is approximately 1 to perform characteristic determination. After calculating Vn1 and the like, the control device 70 turns off the second switch S2 at a time point (time point t4) after a predetermined time has passed. As a result, the first voltage divider circuit 30 is energized, while the second voltage divider circuit 40 is de-energized. As a result, 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 grounding member FG.

[0071] In order to stabilize the voltage division value, the control device 70 implements the switching process of the third switch S3 at the moment when the specified time has passed (time point t5). That is, the first voltage division value Vns02 from the first voltage division circuit 30 is input, and it is determined whether the first voltage division value Vns02 is greater than the limit value Vmax. According to the premise, since the first voltage division value Vns02 is not greater than the limit value Vmax, the third switch S3 is turned off (directly maintained off). As a result, in the first voltage division circuit 30, the power-on and power-off state of the first C detection resistor Rk1 is maintained, and the voltage division ratio of the first voltage division circuit 30 becomes the voltage division ratio α'.

[0072] Then, at a time point (time point t6) after a predetermined time has passed, the control device 70 inputs the first divided voltage value Vns2 and performs a calculation process of Vn2. In addition, here, since the third switch S3 is off, the control device 70 calculates Vns2 / α' and calculates Vn2.

[0073] Then, the control device 70 uses the calculated Vn1 and Vn2 to Figure 7 Rp / / Rn is calculated by the mathematical formula (2) shown in the figure. Then, it is determined that there is leakage based on whether Rp / / Rn is within the normal range. Hereinafter, the effects of the above-described embodiment will be described. (1) In the past, if the insulation resistance Rp and Rn decreased, the influence of the circuit tolerance might temporarily increase. For example, when the actual insulation resistance Rn decreases, the voltage across the insulation resistance Rn decreases accordingly. As a result, the detected Vn1 and Vn2 also decrease and approach zero. When Vn1 and Vn2 approach zero, the influence of the circuit tolerance increases relatively. As a result, Vn1 and Vn2 become equal, Vn1 becomes larger than Vn2, and a reversal of size might occur. In addition, if Fig.10 As shown in FIG. 1 , when the actual insulation resistance (actual Rp / / Rn) decreases, the insulation resistance (detected Rp / / Rn) calculated based on the detected voltage value diverges and sometimes becomes uncertain. As a result, it is impossible to calculate the normal insulation resistance and make a normal judgment. In addition, Fig.10 , Fig.11 In FIG. 1 , the solid line indicates the ideal insulation resistance (detection Rp / / Rn), the dotted line indicates the maximum value of the calculated insulation resistance (detection Rp / / Rn), and the dot-dash line indicates the minimum value.

[0076] Therefore, when the control device 70 detects that the first divided voltage values ​​Vns01 and Vns02 of the first divided voltage circuit 30 are smaller than the threshold value Vth, Fig. 9 As shown, the third switch S3 is switched off, the voltage dividing ratio α of the first voltage dividing circuit 30 is changed to the voltage dividing ratio α', and the detected first voltage dividing value is increased. In this way, since the first voltage dividing value can be increased, the resolution can be substantially reduced even without changing the resolution of the control device 70. Therefore, even after the insulation resistance Rn is reduced, that is, when there is a high possibility that the insulation resistance Rn is short-circuited, the influence of the circuit tolerance can be suppressed and the first voltage dividing value can be detected with high accuracy.

[0077] Specifically, by Fig.10 ) and range E2 (refer to Fig.11 ), by using the leakage detection device 20, the range in which the calculated insulation resistance (detection Rp / / Rn) starts to diverge can be reduced. That is, even if the actual insulation resistance (actual Rp / / Rn) is significantly reduced, the insulation resistance (detection Rp / / Rn) can be calculated with high accuracy without divergence. Fig.10 and Fig.11 As can be seen from the comparison, the maximum value and the minimum value of the calculated insulation resistance (detection Rp / / Rn) can be brought close to the ideal value. Therefore, the leakage detection accuracy can be improved.

[0078] (2) The control device 70 implements a first input step (equivalent to step S103), a second input step (equivalent to step S108), and a leakage detection step (steps S104, S109, S110, and S111), wherein the first input step inputs the first voltage division value Vns1 from the first voltage division circuit 30 when the second voltage division circuit 40 is in the power-on state, and the second input step inputs the first voltage division value Vns2 from the first voltage division circuit 30 when the second voltage division circuit 40 is in the power-off state, and the leakage detection step calculates the insulation resistance and detects leakage based on the first voltage division value Vns1 and the first voltage division value Vns2. In addition, before implementing the first input step or the second input step, the control device 70 inputs the first voltage division values ​​Vns01 and Vns02 of the first voltage division circuit 30, and when the input first voltage division value is less than the threshold value Vth, the third switch S3 is turned off and the voltage division ratio α' of the first voltage division circuit 30 is changed. In this way, since the switching is performed at the timing before detection, the first divided voltage values ​​Vns1 and Vns2 can be detected with high accuracy.

[0079] (3) The control device 70 switches both the first switch S1 and the second switch S2 to on in the first switching step (equivalent to step S101), and inputs the first voltage division value Vns1 and the second voltage division value Vrs1 in the first input step (equivalent to step S103). Then, the control device 70 implements the characteristic determination step (equivalent to step S105) based on the first voltage division value Vns1 and the second voltage division value Vrs1. Thereafter, the control device 70 switches the second switch S2 to off in the second switching step (equivalent to step S106), and inputs the first voltage division value Vns2 in the second input step (equivalent to step S108).

[0080] Thus, during the first input step and the second input step required for the leakage detection, more specifically, during the first input step, the first divided voltage value Vns1 and the second divided voltage value Vrs1 required for the characteristic determination can be input. Therefore, there is no need to switch the second switch S2 and set the time for measurement just to obtain the first divided voltage value Vns1 and the second divided voltage value Vrs1 required for the characteristic determination, and the leakage detection and the characteristic determination can be effectively performed. Therefore, the characteristic determination can be performed at the same time as the leakage detection, and the abnormality of the voltage dividing circuits 30 and 40 can be determined at all times during driving, etc.

[0081] (4) The control device 70 changes the characteristic diagnosis formula by turning the third switch S3 on and off during the characteristic determination process. Thus, even if the insulation resistance Rn decreases, the voltage division ratio can be changed to increase the detected first voltage division value and improve the detection accuracy. Therefore, the decrease in the accuracy of the characteristic determination can be suppressed.

[0082] (5) In use Figure 7 When the value of Rp / / Rn is calculated by the operation formula shown in Mathematical Formula (3) or Mathematical Formula (4) and leakage is detected, 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.

[0083] (Variation Example) A part of the structure of the above-mentioned embodiment may be modified as follows.

[0084] In the above-mentioned embodiment, the processing order of steps S104 and S109 may be arbitrarily changed as long as they are performed before step S110.

[0085] 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.12 As shown, it is connected between the positive side power supply path L1 and the vehicle side grounding member FG. Fig.12 The first voltage divider circuit 30 shown in the modified example is connected between the positive side power supply path L1 and the vehicle side grounding member FG, 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 divider ratio α or a voltage divider ratio α'. Fig.12 The first A detection resistor Rs1 shown is connected to the positive-side power supply path L1 side, and the parallel connection of the first B detection resistor Rk1 ′ and the first C detection resistor Rk1 is connected to the vehicle-side ground FG side.

[0086] in addition, Fig.12 The second voltage divider circuit 40 shown is connected between the positive power supply path L1 and the vehicle ground FG, and divides the voltage between the positive power supply path L1 and the vehicle ground FG (the voltage across the second voltage divider circuit 40) by a voltage divider ratio β. Fig.12 The second A detection resistor Rs2 is connected to the positive power supply path L1, and the second B detection resistor Rk2 is connected to the vehicle ground FG. The control device 70 uses the vehicle ground FG as a reference potential and inputs signals from the first and second voltage divider circuits 30 and 40.

[0087] In addition, Fig.13 In, with Figure 7 Similarly, calculation formulas and characteristic diagnosis formulas are shown for the resistance values ​​R1 and R1' of the first voltage divider circuit 30, the resistance value R2 of the second voltage divider circuit 40, the voltage dividing ratios α and α' of the first voltage divider circuit 30, the voltage dividing ratio β of the second voltage divider circuit 40, and the insulation resistances Rp, Rn, and Rp / / Rn.

[0088] exist Fig.13 In the example, the voltage across the insulation resistor Rp is equivalent to "Vpi", and the voltage across the insulation resistor Rp when the first switch S1 and the second switch S2 are turned on is equivalent to "Vp1". In addition, the voltage across the insulation resistor Rp when the first switch S1 is turned on and the second switch S2 is turned off is equivalent to "Vp2". In addition, the first divided voltage value from the first voltage divider circuit 30 is equivalent to "Vpsi", and the first divided voltage value from the first voltage divider circuit 30 when the first switch S1 and the second switch S2 are turned on is equivalent to "Vps 1". In addition, Figure 7 same.

[0089] ·You can also Fig.14 A part of the first voltage divider circuit 30 in the above embodiment is changed as shown. Specifically, the first voltage divider circuit 30 has a first A detection resistor Rs1, a first C detection resistor Rk1, and a first B detection resistor Rk1', and they are connected in series. Moreover, the third switch S3 is connected in parallel with the first B detection resistor Rk1'. In addition, Fig.14 In the embodiment, the first B detection resistor Rk1 ′ is connected in parallel with the first B detection resistor Rk1 ′, and the third switch S3 as a voltage division ratio switching switch for switching the energized state and the energized cutoff state of the first B detection resistor Rk1 ′ corresponds to the range changing circuit 60 .

[0090] ·You can also Fig.15 A part of the first voltage divider circuit 30 in the above embodiment is changed as shown. Specifically, the first voltage divider circuit 30 has a first A detection resistor Rs1, a first B detection resistor Rk1' (equivalent to a range change circuit), and a first C detection resistor Rk1, and they are connected in series in this order from the vehicle side grounding member FG side. The control device 70 inputs the first voltage divider value Vns0i, Vnsi (i = 1 or 2) from the connection point P101 between the first B detection resistor Rk1' and the first C detection resistor Rk1 in normal times (when the insulation resistance is large). That is, the control device 70 inputs the first voltage divider value Vns0i, Vnsi (i = 1 or 2) from the channel CH1. Then, when the first voltage division value Vns0i (i=1 or 2) input from the channel CH1 is less than the threshold value Vth, the control device 70 inputs the first voltage division value Vnsi (i=1 or 2) from the connection point P102 between the first A detection resistor Rs1 and the first B detection resistor Rk1'. That is, the control device 70 inputs the first voltage division value Vnsi (i=1 or 2) from the channel CH2. Thus, the first voltage division value is input at the voltage division ratio α', and the voltage division ratio of the first voltage division circuit 30 can be changed.

[0092] Furthermore, when the first divided voltage value Vns0i (i=1 or 2) input from the channel CH2 is equal to or greater than the limit value Vmax, the control device 70 inputs the first divided voltage values ​​Vns0i, Vnsi (i=1 or 2) from the channel CH1.

[0093] In the above embodiment, a range changing circuit may be provided in the second voltage dividing circuit 40. Fig.16 As shown, the second voltage divider circuit 40 comprises a second A detection resistor Rs2, a second B detection resistor Rk2, a second C detection resistor Rk2', and a fourth switch S4 as a voltage division ratio switching switch. The fourth switch S4 is connected in series with the second B detection resistor Rk2, and switches the power-on state and the power-off state of the second B detection resistor Rk2. The second A detection resistor Rs2 is connected in series with the second C detection resistor Rk2', and the series connection of the fourth switch S4 and the second B detection resistor Rk2 is connected in parallel with the second C detection resistor Rk2'. The second C detection resistor Rk2' and the fourth switch S4 are equivalent to the range change circuit of the second voltage divider circuit 40.

[0095] Fig.16 The second voltage dividing circuit 40 shown can change the voltage dividing ratio β to the voltage dividing ratio β′ by turning the fourth switch S4 on and off.

[0096] In addition, Fig.17 In, with Figure 7 Similarly, the calculation formulas and characteristic diagnosis formulas for the resistance values ​​R1 and R1' of the first voltage divider circuit 30, the resistance values ​​R2 and R2' of the second voltage divider circuit 40, the voltage division ratios α and α' of the first voltage divider circuit 30, the voltage division ratios β and β' of the second voltage divider circuit 40, and the insulation resistances Rp, Rn, and Rp / / Rn are shown. Fig.17 , the resistance value of the second C detection resistor Rk2' is "Rk2'". In addition, the resistance value of the second voltage divider circuit 40 when the fourth switch is turned on is "R2", and the resistance value of the second voltage divider circuit 40 when the fourth switch is turned off is "R2'". This can improve the determination accuracy of the characteristic determination.

[0097] In the leakage detection process of the above-described embodiment, when the detection voltages Vn1 and Vn2 calculated in step S104 and step S109 are sufficiently small, a process for suppressing the influence of circuit tolerance or the like may be added.

[0098] based on Fig.18 After the processing of step S109, the control device 70 determines whether the calculated detection voltage Vn1 is greater than the first threshold value TL1 (step S601). The first threshold value TL1 is set to an arbitrary value taking into account circuit tolerance, etc. Fig.11As shown, the voltage value when the maximum value of Rp / / Rn starts to diverge (the time shown in the range E2) is set as the first threshold value TL1.

[0099] When the determination result is positive, that is, when it is greater than the first threshold value TL1, the control device 70 determines whether the calculated detection voltage Vn2 is greater than the second threshold value TL2 (step S602). The second threshold value TL2 is set to an arbitrary value taking into account circuit tolerance, etc. In addition, the first threshold value TL1 and the second threshold value TL2 can be the same value or different values.

[0100] When the determination result of step S602 is affirmative, it is considered that the determination can be made correctly based on the value of Rp / / Rn calculated by equation (3), and the control device 70 performs the processing after step S110 in the same manner as in the first embodiment.

[0101] On the other hand, if the determination result of step S601 or step S602 is negative, the control device 70 sets the fixed value to the value of Rp / / Rn (step S603). The fixed value is a value indicating leakage and is determined according to the required specifications of the insulation resistances Rp and Rn. For example, 4 kΩ is set as the fixed value.

[0102] After step S603, the control device 70 implements step S110 to detect leakage. In step S603, if a fixed value is set, it is determined that there is a constant leakage.

[0103] As described above, 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 becomes greater, and the value of the composite calculation formula of the insulation resistances Rp and Rn may be uncertain. 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 calculation formula of the insulation resistances Rp and Rn is not calculated, but leakage is detected. Thus, leakage can be accurately detected without being affected by circuit tolerance.

[0104] ·You can also Fig.19 A part of the first voltage divider circuit 30 in the above embodiment is changed as shown. That is, in the first voltage divider circuit 30, the first A detection resistor Rs1 may be arranged on the negative side power supply path L2 side, and the parallel connection of the first B detection resistor Rk1' and the first C detection resistor Rk1 may be arranged on the vehicle side grounding member FG side. Similarly, in the second voltage divider circuit 40, the second A detection resistor Rs2 may be arranged on the negative side power supply path L2 side, and the second B detection resistor Rk2 may be arranged on the vehicle side grounding member FG side. In addition, in this case, it is necessary to detect the voltage between the vehicle side grounding member FG and the connection point via a differential amplifier circuit.

[0105] 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.

[0106] In the above embodiment, the third switch S3 may be a bipolar switch (semiconductor switch) such as a transistor, or may be a mechanical relay or the like.

[0107] In the above embodiment, the range changing circuit 60 may be configured with one stage to change the voltage dividing ratio by one stage, but the range changing circuit 60 may be configured with multiple stages to change the voltage dividing ratio by multiple stages.

[0108] In the above-described embodiment, if the characteristic determination is not performed, the second voltage dividing circuit 40 may be changed to a simple resistor. (Second Embodiment) Hereinafter, a second embodiment in which a part of the structure of the first embodiment is changed will be described.

[0110] As described in the first embodiment, one of the reasons why the first voltage divider value becomes smaller is that the insulation resistance Rn becomes smaller, but other reasons may also be considered as the reason why the first voltage divider value becomes smaller. For example, it is considered that the insulation resistance on the side where the first voltage divider circuit 30 is not connected in parallel (the insulation resistance Rp on the positive side in the first embodiment) becomes too large, which is also one of the reasons why the first voltage divider value becomes smaller. Since this insulation resistance is the resistance on the vehicle side, it is difficult to determine the maximum value based on the specifications. In particular, when the relay switches of the power supply paths L1 and L2 are disconnected and the power supply between the electrical load such as the rotating motor and the battery pack 10 is cut off, the insulation resistances Rn and Rp become almost infinite. Therefore, even if the voltage divider ratio becomes larger, the first voltage divider value may be smaller than expected.

[0111] Therefore, in the second embodiment, a design is made so that even if the insulation resistance of the side where the first voltage divider circuit 30 is not connected in parallel (the insulation resistance Rp of the positive side in the second embodiment) becomes large, the first voltage divider value can be within an appropriate range. In addition, in the second embodiment, based on this design, the range change circuit 60 is composed of multiple stages, so that the voltage divider ratio can be changed in multiple stages. The following is a detailed description.

[0112] First, the circuit structure of the second embodiment is described. The same symbols are used for the same structures as those of the first embodiment, and the description thereof is omitted. Fig. 20As shown, the first voltage divider circuit 130 of the second embodiment is connected between the vehicle side grounding member FG and the negative side power supply path L2, and divides 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 130) by a voltage divider ratio α, a voltage divider ratio α10, or a voltage divider ratio α100. In addition, in the second embodiment, the negative side power supply path L2 is equivalent to the first power supply path, and the positive side power supply path L1 is equivalent to the second power supply path.

[0113] The structure of the first voltage divider circuit 130 is described in detail. The first voltage divider circuit 130 includes a first A detection resistor Rs1 and a range change circuit 160. The range change circuit 160 includes a first B detection resistor Rk1, a first C detection resistor Rk10, and a first D detection resistor Rk100. The first B detection resistor Rk1, the first C detection resistor Rk10, and the first D detection resistor Rk100 are connected in parallel.

[0114] In more detail, the third switch S3 is connected in series with the first B detection resistor Rk1, and the third switch S3 is used to switch between the power-on state and the power-off state. In addition, the thirtieth switch S30 is connected in series with the first C detection resistor Rk10, and the power-on state and the power-off state can be switched through the thirtieth switch S30. Moreover, the first D detection resistor Rk100 is connected in parallel with the series connection body composed of the first B detection resistor Rk1 and the third switch S3 and the series connection body composed of the first C detection resistor Rk10 and the thirtieth switch S30. The parallel connection body is equivalent to the range change circuit 160.

[0115] The range change circuit 160 is connected in series with the first A detection resistor Rs1. In addition, a Zener diode Da is connected in parallel with the range change circuit 160. The anode side of the Zener diode Da is connected to the negative side power supply path L2.

[0116] The first A detection resistor Rs1 is connected to the vehicle-side grounding member FG side, and the range change circuit 160 is connected to the negative-side power supply path L2 side. One end of the first output line L11 is connected to the first connection point P1 between the first A detection resistor Rs1 and the range change circuit 160. The voltage signal (first divided voltage value) from the first voltage divider circuit 130 is output via the first output line L11.

[0117] When the third switch S3 and the thirtieth switch S30 are turned on, the first B detection resistor Rk1 , the first C detection resistor Rk10 , and the first D detection resistor Rk100 are energized, and the voltage division ratio of the first voltage division circuit 130 becomes α.

[0118] When the third switch S3 is turned off and the thirtieth switch S30 is turned on, the first B detection resistor Rk1 is in a power-off state, the first C detection resistor Rk10 and the first D detection resistor Rk100 are in a power-on state, and the voltage dividing ratio of the first voltage dividing circuit 130 becomes α10.

[0119] When the third switch S3 and the thirtieth switch S30 are turned off, the first B detection resistor Rk1 and the first C detection resistor Rk10 are turned off, the first D detection resistor Rk100 is turned on, and the voltage dividing ratio of the first voltage dividing circuit 130 becomes α100.

[0120] The third switch S3 and the thirtieth switch S30 are controlled to be turned on and off by the control device 70. Moreover, the resistance value of the first C detection resistor Rk10 is much larger than the resistance value of the first B detection resistor Rk1, for example, a value of about 10 times. Similarly, the resistance value of the first D detection resistor Rk100 is much larger than the resistance value of the first C detection resistor Rk10, for example, a value of about 10 times.

[0121] Therefore, the voltage division ratio α10 becomes larger relative to the voltage division ratio α, and the voltage division ratio α100 becomes larger relative to the voltage division ratio α10 (α<α10<α100). Moreover, the larger the voltage division ratio is, the larger the first voltage division value (voltage signal) is proportional to it. In addition, in the second embodiment, the voltage division ratio α10 is about 10 times the voltage division ratio α, and the voltage division ratio α100 is about 10 times the voltage division ratio α10 (that is, about 100 times the voltage division ratio α).

[0122] like Fig. 20 As shown, in the second embodiment, a bypass circuit 190 composed of a series connection of a resistor R3 and a fourth switch S4 (switching switch) is provided between the positive-side power supply path L1 and the vehicle-side grounding member FG. The fourth switch S4 is configured to be switched on and off by the control device 70. When the fourth switch S4 is turned on, electricity is supplied between the positive-side power supply path L1 and the vehicle-side grounding member FG via the resistor R3. In addition, when the fourth switch S4 is turned off, the bypass circuit 190 is in a power-off state, and electricity is not supplied between the positive-side power supply path L1 and the vehicle-side grounding member FG via the resistor R3.

[0123] The value of the resistor R3 is smaller than the insulation resistance Rp on the positive electrode side between the positive electrode side power supply path L1 and the vehicle side ground FG and is larger than the value allowed as the normal value of the insulation resistance Rp.

[0124] like Fig. 20As shown, the bypass circuit 190 is connected in parallel with the insulation resistance Rp on the positive electrode side. Therefore, no matter how large the insulation resistance Rp on the positive electrode side becomes, it will not substantially increase due to the resistor R3 connected in parallel. That is, when the fourth switch S4 is turned on, the potential of the vehicle-side grounding member FG rises to the positive electrode side (positive electrode side power supply path L1 side) of the battery pack 10.

[0125] Furthermore, the control device 70 of the second embodiment can switch the detection range of the first divided voltage value into three stages by turning on and off the switches S3, S30, and S4. Fig.21 As shown, in the case of the detection range LV1, the third switch S3 and the thirtieth switch S30 are turned on, and the first voltage division value is obtained with the voltage division ratio α. At this time, since the fourth switch S4 is turned off, the potential of the vehicle side grounding member FG does not increase. Therefore, in the case of the detection range LV1, if the value of the insulation resistance Rp on the positive side becomes larger than expected, it may be affected.

[0126] Furthermore, in the case of the detection range LV2, the third switch S3 is turned off, while the thirtieth switch S30 is turned on, and the first voltage division value is obtained at the voltage division ratio α10. At this time, since the fourth switch S4 is turned on, the potential of the vehicle-side grounding member FG increases. Therefore, in the case of the detection range LV2, even if the value of the insulation resistance Rp on the positive side increases, the influence can be substantially suppressed. Similarly, in the case of the detection range LV3, the third switch S3 and the thirtieth switch S30 are turned off, and the first divided voltage value is obtained with the voltage division ratio α100. At this time, since the fourth switch S4 is turned on, the potential of the vehicle-side grounding member FG increases. Therefore, in the case of the detection range LV3, even if the value of the insulation resistance Rp on the positive side increases, the influence can be substantially suppressed.

[0128] Next, based on Figure 22 to Figure 26 , the leakage detection process of the second embodiment is described in detail. Fig.26 In FIG. 1 , the calculation formulas of the resistance values ​​CK1, CK10, CK100 of the range change circuit 160, the resistance values ​​R1, R10, R100 of the first voltage divider circuit 130, the resistance value R2 of the second voltage divider circuit 40, the voltage divider ratios α, α10, α100 of the first voltage divider circuit 130, the voltage divider ratio β of the second voltage divider circuit 40, and the insulation resistances Rp, Rn, Rz (=Rp / / Rn) are shown. Fig.26 , each value for each detection range LV1 to LV3 is shown.

[0129] In addition, the resistance value of the first A detection resistor Rs1 is "Rs1", the resistance value of the first B detection resistor Rk1 is "Rk1", the resistance value of the first C detection resistor Rk10 is "Rk10", and the resistance value of the first D detection resistor Rk100 is "Rk100". In addition, the resistance value of the resistor R3 is "R3".

[0130] Furthermore, the resistance value (composite resistance value) of the range changing circuit 160 in the detection range LV1 is "CK1", the resistance value of the range changing circuit 160 in the detection range LV2 is "CK10", and the resistance value of the range changing circuit 160 in the detection range LV3 is "CK100". Since other values ​​are the same as those in the first embodiment, reference is made to the first embodiment and the description is omitted.

[0131] Fig. 22 The leakage detection process shown is performed at predetermined intervals (for example, every several tens of milliseconds) by the control device 70. When the leakage detection process is performed, first, the control device 70 turns on the second switch S2 (step S301).

[0132] Next, the control device 70 determines whether the vehicle is just started (for example, the ignition switch is just turned on) (step S302). If the determination result is positive, the control device 70 turns on the first switch S1 (step S303) and sets the detection range to "LV1" (step S304). Fig.21 As shown, when the detection range is set, the control device 70 switches the switches S3, S30, and S4 on and off according to the set detection ranges LV1 to LV3. When the detection range LV1 is set, the voltage division ratio of the first voltage division circuit 130 is the voltage division ratio α.

[0133] After the process of step S304 or when the determination result of step S302 is negative, the control device 70 sets i=1 after a predetermined time has passed (step S305 ).

[0134] Then, the control device 70 performs a range switching process of the detection range (step S306). Fig.23 To illustrate the range switching process in step S306. In addition, in the range switching process in step S306, i is replaced with 1. For example, Fig.23 Replace Vns0i with Vns01.

[0135] exist Fig.23In the range switching process shown, the control device 70 inputs (detects) the first voltage division value Vns0i from the first voltage division circuit 130 (step S401). In addition, in the case of the detection range LV1, the first voltage division value Vns0i=α×Vni, in the case of the detection range LV2, the first voltage division value Vns0i=α10×Vni, and in the case of the detection range LV3, the first voltage division value Vns0i=α100×Vni.

[0136] Next, the control device 70 determines whether the detected first divided voltage value Vns0i is smaller than a threshold value Vth (step S402). The threshold value Vth is an arbitrary value, and is set according to the resolution of the control device 70, the required detection accuracy, and the like.

[0137] When the judgment result of step S402 is affirmative, the control device 70 judges whether the detection range in the current setting is the detection range LV3 (step S403). When the judgment result is affirmative, since the detection range cannot be further increased, the control device 70 ends the switching process. On the other hand, when the judgment result of step S403 is negative, the control device 70 increases the setting of the detection range by one stage (step S404). For example, when the detection range in the current setting is the detection range LV1, it is set to the detection range LV2, and when the detection range in the current setting is the detection range LV2, it is set to the detection range L3. Then, as Fig.21 As shown, the control device 70 switches the switches S3, S30, and S4 on and off according to the changed detection range LV2 to LV3. Then, the control device 70 performs the process of step S401 again.

[0138] On the other hand, when the determination result of step S402 is negative, that is, when the detected first divided voltage value Vns0i is greater than the threshold value Vth, the control device 70 determines whether the detected first divided voltage value Vns0i is greater than the limit value Vmax (step S405). The limit value Vmax is an arbitrary value, which is set according to the resolution, withstand voltage, detection accuracy, etc. of the control device 70. When the determination result of step S405 is negative, the control device 70 ends the range switching process. On the other hand, when the judgment result of step S405 is affirmative, the control device 70 judges whether the detection range in the current setting is the detection range LV1 (step S406). When the judgment result is affirmative, since the detection range cannot be lowered, the control device 70 ends the switching process. On the other hand, when the judgment result of step S406 is negative, the control device 70 lowers the setting of the detection range by one stage (step S407). For example, when the detection range in the current setting is the detection range LV3, it is set to the detection range LV2, and when the detection range in the current setting is the detection range LV2, it is set to the detection range LV1. Then, as Fig.21 As shown, the control device 70 switches the switches S3, S30, and S4 on and off according to the changed detection ranges LV1 to LV2. Then, the control device 70 performs the process of step S401 again.

[0140] like Fig. 22 As shown, after the range switching process of step S306 is completed, at the time when the predetermined time has passed, the control device 70 performs the detection process of Vn1 (step S307). Fig.24 To illustrate the detection process of Vn1. In addition, in the detection process of step S307, i is replaced with 1. For example, Fig.24 Vni is replaced by Vn1, and Vnsi is replaced by Vns1.

[0141] like Fig.24 As shown in FIG. 5 , when the detection process starts, the control device 70 inputs (detects) the first voltage division value Vnsi from the first voltage division circuit 130 (step S501). Next, the control device 70 determines whether the detection range currently set is the detection range LV3 (step S502). If the determination result is positive, the control device 70 calculates Vnsi / α100 and calculates Vni (step S503). Then, the detection process ends.

[0142] On the other hand, if the determination result of step S502 is negative, the control device 70 determines whether the detection range currently set is the detection range LV2 (step S504). If the determination result is positive, the control device 70 calculates Vnsi / α10 and calculates Vni (step S505). Then, the detection process ends.

[0143] On the other hand, when the determination result of step S504 is negative, that is, when the currently set detection range is the detection range LV1, the control device 70 calculates Vnsi / α and Vni (step S506). Then, the detection process ends.

[0144] like Fig. 22 As shown, after the detection process of step S307 is completed, the control device 70 switches the second switch S2 to off at a time when a predetermined time has passed (step S308). Thereafter, the control device 70 sets i=2 at a time when a predetermined time has passed (step S309).

[0145] Then, the control device 70 performs the range switching process (step S310). The switching process of step S310 is different from the switching process of step S306. Fig.23 In the description of , if i=2 is replaced, it is the same as above. For example, if Vns0i is replaced by Vns02, it is the same as above. Therefore, the description is omitted here.

[0146] like Fig. 22 As shown, after the switching process of step S310 is completed, at the time when the predetermined time has passed, the control device 70 performs the detection process of Vn2 (step S311). In addition, the detection process of step S311 is performed after the detection process of step S307 and Fig.24 In the description of , if i=2 is replaced, it is the same as above. For example, if Vnsi is replaced by Vns2, and Vni is replaced by Vn2, it is the same as above. Therefore, the description is omitted here.

[0147] When the detection process of step S311 is completed, Fig. 22 As shown in FIG. 1 , the control device 70 performs an insulation resistance calculation process to calculate the insulation resistance (step S312 ). Fig.25 The insulation resistance calculation process will be described below.

[0148] In the insulation resistance calculation process of step S312, the control device 70 determines whether the currently set detection range is the detection range LV3 (step S601). If the determination result is positive, the control device 70 calculates the insulation resistance based on the detected Vn1 and Vn2 (step S602). Fig.26 The insulation resistance Rz in the detection range LV3 can be calculated by the mathematical formula (13). Fig.26 The insulation resistances Rp and Rn are obtained by using the equations (16) and (18) described above. Then, the insulation resistance calculation process is terminated. On the other hand, if the determination result of step S601 is negative, the control device 70 determines whether the currently set detection range is the detection range LV2 (step S603). If the determination result is positive, the control device 70 calculates the insulation resistance based on the detected Vn1 and Vn2 (step S604). Fig.26The insulation resistance Rz in the detection range LV2 can be calculated by the mathematical formula (12). Fig.26 The insulation resistances Rp and Rn are obtained by using the equations (15) and (18) described above. Then, the insulation resistance calculation process is terminated.

[0150] On the other hand, when the determination result of step S603 is negative, that is, when the currently set detection range is the detection range LV1, the control device 70 calculates the insulation resistance based on the detected Vn1 and Vn2 (step S605). Fig.26 The insulation resistance Rz in the detection range LV1 can be calculated by the mathematical formula (11). Fig.26 The insulation resistances Rp and Rn are obtained by using the equations (14) and (17) described above. Then, the insulation resistance calculation process is terminated.

[0151] like Fig. 22 As shown in FIG. 1 , after the insulation resistance calculation process is completed, the control device 70 determines whether there is leakage based on the calculated insulation resistance (step S313). In step S313, for example, whether there is leakage is determined based on whether the calculated insulation resistance Rz is within a predetermined normal range. In addition, when the insulation resistances Rp and Rn are calculated, leakage can also be determined based on whether they are less than the determination thresholds Rp0 and Rn0, respectively.

[0152] When the determination result of step S313 is positive (when leakage is detected), the control device 70 implements a process for dealing with leakage (step S314), and ends the leakage detection process. The process for dealing with leakage refers to, for example, a process for notifying an external device of leakage and issuing a warning. On the other hand, when the determination result of step S313 is negative (when leakage is not detected), the control device 70 considers it normal and directly ends the leakage detection process.

[0153] Next, refer to Fig. 27 The detection time of the first divided voltage value and the switching time of the detection range LV1 to L3 are explained. Fig. 27 In the description, it is assumed that initially (time point t10), the insulation resistances Rp and Rn are normal and are within the setting of the detection range LV1. In the case of the detection range LV1, the switches S1, S2, S3, and S30 are turned on, and the fourth switch S4 is turned off (time point t11). As a result, the voltage division ratio of the first voltage division circuit 130 becomes the voltage division ratio α. In addition, since the fourth switch S4 is turned off, the potential of the vehicle-side grounding member FG does not increase.

[0154] In order to stabilize the first voltage division value, the control device 70 implements a range switching process at a time point after a predetermined time has passed (time point t12). That is, the first voltage division value Vns01 from the first voltage division circuit 130 is input, and it is determined whether the first voltage division value Vns01 is greater than the threshold value Vth and less than the limit value Vmax. According to the premise, since the first voltage division value Vns01 is greater than the threshold value Vth and less than the limit value Vmax, the detection range LV1 is maintained. Thereafter, at a time point after a predetermined time has passed (time point t13), the control device 70 inputs the first voltage division value Vns1 and calculates Vn1.

[0155] After calculating Vn1, the control device 70 turns off the second switch S2 at the time when the prescribed time has passed (time point t14). In order to stabilize the voltage division value, the control device 70 performs a range switching process at the time when the prescribed time has passed (time point t15). That is, the first voltage division value Vns02 from the first voltage division circuit 130 is input, and it is determined whether the first voltage division value Vns02 is greater than the threshold value Vth and less than the limit value Vmax. According to the premise, since the first voltage division value Vns02 is greater than the threshold value Vth and less than the limit value Vmax, the detection range LV1 is maintained.

[0156] Then, the control device 70 inputs the first voltage division value Vns2 and calculates Vn2 at a time point (time point t16) after a predetermined time has passed. Then, the control device 70 uses the calculated Vn1 and Vn2 to calculate Fig.26 The insulation resistance Rz is calculated using the mathematical formula (11) shown in the figure to determine whether there is leakage. Then, at time point t21 after a predetermined time has passed, the second switch S2 is turned on. In addition, the description is based on the premise that the first voltage division value is smaller than the threshold value Vth in the detection range LV1 after time point t20 between time point t21 and time point t22. That is, the description is based on the premise that the insulation resistance Rp increases or the insulation resistance Rn decreases in order to detect the first voltage division value in the detection range LV1 at time point t20.

[0158] The control device 70 performs range switching processing at a time point (time point t22) after a predetermined time has passed since time point t21. That is, the first voltage division value Vns01 from the first voltage division circuit 130 is input, and it is determined whether the first voltage division value Vns01 is greater than the threshold value Vth and less than the limit value Vmax. According to the premise, since the first voltage division value Vns01 is smaller than the threshold value Vth, it is set to the detection range LV2. As a result, the third switch S3 is turned off and the voltage division ratio is changed to α10. In addition, at Fig. 27In the column of the detected value Vns, the detected voltage when the voltage division ratio α is maintained is indicated by a dotted line. In addition, the fourth switch S4 is turned on, and the potential of the vehicle-side grounding member FG increases. Fig. 27 In the column of the physical value Vn, the voltage (potential) when the fourth switch S4 remains off is indicated by a dotted line.

[0159] The control device 70 inputs the first voltage division value Vns1 and calculates Vn1 at a time point after a predetermined time has passed (time point t23). After calculating Vn1, the control device 70 disconnects the second switch S2 at a time point after a predetermined time has passed (time point t24). In order to stabilize the voltage division value, the control device 70 implements a range switching process at a time point after a predetermined time has passed (time point t25). That is, the first voltage division value Vns02 from the first voltage division circuit 130 is input, and it is determined whether the first voltage division value Vns02 is greater than the threshold value Vth and less than the limit value Vmax. According to the premise, since the first voltage division value Vns02 is greater than the threshold value Vth and less than the limit value Vmax, the detection range LV2 is maintained. Then, at a time point (time point t26) after a predetermined time has passed, the control device 70 inputs the first voltage division value Vns2 and calculates Vn2. Then, the control device 70 uses the calculated Vn1 and Vn2 to calculate Fig.26 The insulation resistance Rz is calculated using the mathematical formula (12) shown in the figure to determine whether there is leakage.

[0161] Then, at time point t31 after a predetermined time has passed, the second switch S2 is turned on. In addition, the description is based on the premise that after time point t30 between time point t31 and time point t32, the first voltage division value is smaller than the threshold value Vth in the detection range LV2. That is, the description is based on the premise that at time point t30, the insulation resistance Rp further increases, or the insulation resistance Rn further decreases, and the voltage division ratio is inappropriate in the detection range LV2.

[0162] The control device 70 performs range switching processing at a time point (time point t32) after a predetermined time has passed since time point t31. That is, the first voltage divider value Vns01 from the first voltage divider circuit 130 is input, and it is determined whether the first voltage divider value Vns01 is greater than the threshold value Vth and less than the limit value Vmax. According to the premise, since the first voltage divider value Vns01 is smaller than the threshold value Vth, it is set to the detection range LV3. Thus, the voltage divider ratio α is changed to 100. In addition, Fig. 27 In the column of the detected value Vns, the detected voltage when the voltage division ratio α is maintained at 10 is indicated by a dotted line. In addition, the fourth switch S4 is turned on, and the potential of the vehicle-side grounding member FG increases. Fig. 27In the column of the physical value Vn, the voltage (potential) when the fourth switch S4 remains off is indicated by a dotted line.

[0163] The control device 70 inputs the first voltage division value Vns1 and calculates Vn1 at a time point (time point t33) after a predetermined time has passed. After calculating Vn1, the control device 70 disconnects the second switch S2 at a time point (time point t34) after a predetermined time has passed. In order to stabilize the voltage division value, the control device 70 implements a switching process of the detection range at a time point (time point t35) after a predetermined time has passed. That is, the first voltage division value Vns02 from the first voltage division circuit 130 is input, and it is determined whether the first voltage division value Vns02 is greater than the threshold value Vth and less than the limit value Vmax. According to the premise, since the first voltage division value Vns02 is greater than the threshold value Vth and less than the limit value Vmax, the detection range LV3 is maintained.

[0164] Then, at a time point (time point t36) after a predetermined time has passed, the control device 70 inputs the first voltage division value Vns2 and calculates Vn2. Then, the control device 70 uses the calculated Vn1 and Vn2 to calculate Fig.26 The insulation resistance Rz is calculated using the mathematical formula (13) shown in the figure to determine whether there is leakage. Hereinafter, the effects of the above-described embodiment will be described.

[0166] (11) When the insulation resistance Rp increases, the first voltage division value decreases. Therefore, in the second embodiment, a bypass circuit 190 consisting of a series connection of a resistor R3 and a fourth switch S4 is provided between the positive-side power supply path L1 and the vehicle-side grounding member FG. Then, when the detection range is expanded, that is, when the detection range is set to LV2 or LV3, the fourth switch S4 is turned on to raise the potential of the vehicle-side grounding member FG to the positive side of the battery pack 10 (positive-side power supply path L1 side). Thus, when the detection range is set to LV2 or LV3, no matter how large the insulation resistance Rp on the positive side becomes, the substantial influence can be suppressed by the resistor R3 connected in parallel.

[0167] (12) When the first divided voltage values ​​Vns01 and Vns02 input to the first voltage divider circuit 130 are less than the threshold value Vth, the control device 70 turns on the fourth switch S4 and energizes the positive-side power supply path L1 and the vehicle-side ground FG via the resistor R3. Thus, the resistor R3 can be energized at an appropriate time and the influence of the insulation resistance Rp can be suppressed.

[0168] (13) The value of the resistor R3 is smaller than the insulation resistance Rp on the positive electrode side between the positive electrode side power supply path L1 and the vehicle side grounding member FG, and is larger than the value allowed as the normal value of the insulation resistance Rp. Therefore, no matter how large the insulation resistance Rp on the positive electrode side becomes, the resistor R3 connected in parallel can substantially suppress the influence.

[0169] (Variation of the Second Embodiment) The second embodiment described above may be implemented in combination with the first embodiment described above or its modified example. In the second embodiment, the range changing circuit 160 is configured with two stages and is configured to be able to change the voltage dividing ratio in two stages, but it may be configured to be able to change in one stage, or in three or more stages.

[0171] In the second embodiment, only the resistor Rk1 may be provided instead of the range change circuit 160. That is, the voltage division ratio of the first voltage divider circuit 130 may not be changed. In this case, when the first voltage division values ​​Vns01 and Vns02 input to the first voltage divider circuit 130 are smaller than the threshold value Vth, only the fourth switch S4 may be turned on.

[0172] In the second embodiment, the fourth switch S4 may not be provided. That is, current may always flow between the positive-side power supply path L1 and the vehicle-side ground FG via the resistor R3. Even in this case, the influence of the increase in the insulation resistance Rp can be suppressed.

[0173] In the above second embodiment, if Fig.12 As shown, when the first voltage divider circuit 130 and the second voltage divider circuit 40 are provided between the positive power supply path L1 and the vehicle ground FG, a bypass circuit 190 (resistor R3 etc.) may be provided between the negative power supply path L2 and the vehicle ground FG.

[0174] Hereinafter, characteristic structures extracted from the above-mentioned embodiments will be described. [Structure 1] A leakage detection device (20) detects leakage between a power path (L1, L2) connected to a terminal of a battery (10) and a grounding member (FG), the leakage detection device comprising: A first voltage divider circuit (30, 130), one end of the first voltage divider circuit being connected to the power supply path side, and the other end of the first voltage divider circuit being connected to the grounding member side; A resistance circuit (40), one end of which is connected to the power supply path side, the other end of which is connected to the grounding member side, and which is connected in parallel with the first voltage divider circuit; a switch unit (S2), the switch unit being configured to switch between an energized state and an energized disconnected state of the resistor circuit; and A control unit (70) controls the switching of the switch unit, inputs a first voltage division value (Vns1, Vns2) of the first voltage division circuit, and calculates insulation resistance and detects leakage based on the input first voltage division value. The first voltage dividing circuit has a range changing circuit (60, 160) for changing the voltage dividing ratio of the first voltage dividing circuit. When the input first divided voltage value (Vns01, Vns02) of the first divided voltage circuit is smaller than a threshold value (Vth), the control unit changes the voltage division ratio of the first divided voltage circuit through the range change circuit so as to increase the first divided voltage value. [Structure 2] The leakage detection device as described in structure 1, wherein: The control unit is configured to implement a first input step, a second input step, and a leakage detection step. The first input step inputs a first divided voltage value (Vns1) from the first divided voltage circuit when the resistor circuit is in an energized state. The second input step inputs the first divided voltage value (Vns2) from the first divided voltage circuit when the resistor circuit is in the power-on / off state. The leakage detection step calculates the insulation resistance and detects leakage based on the first voltage division value input in the first input step and the first voltage division value input in the second input step. The control unit inputs a first voltage dividing value (Vns01, Vns02) of the first voltage dividing circuit before performing the first input step or the second input step, and changes the voltage dividing ratio of the first voltage dividing circuit when the input first voltage dividing value is smaller than a threshold value. [Structure 3] A leakage detection device as described in structure 1 or 2, wherein: The above resistance circuit is the second voltage divider circuit. The control unit is configured to input the voltage division values ​​from the first voltage division circuit and the second voltage division circuit, and implement the first switching step, the first input step, the second switching step, the second input step, the characteristic determination step, and the leakage detection step. The first switching step controls the switch unit and switches the second voltage divider circuit to an energized state. The first input step is after the first switching step, when the second voltage divider circuit is in the power-on state, inputting a first voltage divider value (Vns1) from the first voltage divider circuit and inputting a second voltage divider value (Vrs1) from the second voltage divider circuit, The second switching step is to control the switch unit after the first input step, and switch the second voltage divider circuit to a power-on / off state. The second input step is performed after the second switching step, when the second voltage divider circuit is in the power-on / off state, inputting the first voltage divider value (Vns2) from the first voltage divider circuit, The characteristic determination step determines whether the first voltage divider circuit and the second voltage divider circuit are abnormal based on the first voltage divider value and the second voltage divider value input in the first input step. The leakage detection step calculates insulation resistance and detects leakage based on the first divided voltage value input in the first input step and the first divided voltage value input in the second input step. [Structure 4] A leakage detection device as described in any one of Structures 1 to 3, wherein: The first voltage divider circuit comprises a first A detection resistor (Rs1), a first B detection resistor (Rk1'), a first C detection resistor (Rk1) and a voltage divider ratio switching switch (S3), wherein the voltage divider ratio switching switch is connected in series with the first C detection resistor (Rk1) and switches the power-on state and the power-off state of the first C detection resistor (Rk1). The series connection body of the first C detection resistor (Rk1) and the voltage division ratio switching switch (S3) is connected in parallel with the first B detection resistor (Rk1') to form a parallel connection body. The first A detection resistor (Rs1) is connected in series with the parallel connection body. The control unit changes the voltage dividing ratio of the first voltage dividing circuit by switching the voltage dividing ratio switching switch. [Structure 5] A leakage detection device as described in any one of Structures 1 to 3, wherein: The first voltage divider circuit comprises a first A detection resistor (Rs1), a first B detection resistor (Rk1'), a first C detection resistor (Rk1) and a voltage divider ratio switching switch (S3), wherein the voltage divider ratio switching switch is connected in parallel with the first B detection resistor (Rk1') and switches the power-on state and the power-off state of the first B detection resistor (Rk1'). The first A detection resistor (Rs1), the first B detection resistor (Rk1'), and the first C detection resistor (Rk1) are connected in series. The control unit changes the voltage dividing ratio of the first voltage dividing circuit by switching the voltage dividing ratio switching switch. [Structure 6] A leakage detection device as described in any one of Structures 1 to 3, wherein: The first voltage divider circuit has a first A detection resistor (Rs1), a first B detection resistor (Rk1') and a first C detection resistor (Rk1), and they are connected in series. The control unit normally inputs a first voltage divider value from a connection point (P101) between the first B detection resistor Rk1' and the first C detection resistor Rk1. When the input first voltage divider value is less than a threshold value, the control unit changes the voltage divider ratio of the first voltage divider circuit by inputting a first voltage divider value from a connection point (P102) between the first A detection resistor Rs1 and the first B detection resistor Rk1'. [Structure 7] A leakage detection device as described in any one of Structures 1 to 6, wherein: The control unit detects leakage without calculating the insulation resistance value when the voltage (Vn1, Vn2) across the first voltage dividing circuit calculated based on the first voltage dividing value and the voltage dividing ratio input from the first voltage dividing circuit is lower than the determination threshold value (TL1, TL2). [Structure 8] A leakage detection device as described in any one of Structures 1 to 7, wherein: The power supply path includes a positive-side power supply path (L1) connected to the positive terminal of the battery and a negative-side power supply path (L2) connected to the negative terminal of the battery. The first voltage divider circuit and the resistor circuit are connected to a first power path that is either the power path on the positive side or the power path on the negative side. A resistor (R3) is provided between a second power path different from the first power path in the power path on the positive electrode side and the power path on the negative electrode side and the grounding member. [Structure 9] The leakage detection device as described in structure 8, wherein: A switch (S4) is connected in series with the above resistor. When the input first divided voltage value ( Vns01 , Vns02 ) of the first divided voltage circuit is smaller than a threshold value (Vth), the control unit turns on the switch and conducts electricity between the second power supply path and the ground via the resistor. [Structure 10] A leakage detection device as described in structure 8 or 9, wherein: The value of the resistance is smaller than the insulation resistance between the second power supply path and the ground and is larger than a value allowed as a normal value of the insulation resistance. [Structure 11] A leakage detection device (20) detects leakage between a power path (L1) on the positive side connected to the positive terminal of a battery (10) and a grounding member (FG), and leakage between a power path (L2) on the negative side connected to the negative terminal of the battery and a grounding member (FG), the leakage detection device comprising: A first voltage divider circuit (130), one end of which is connected to the first power path as either the positive power path or the negative power path, and the other end is connected to the grounding member; a resistance circuit (40), one end of which is connected to the first power supply path side, the other end of which is connected to the grounding member side, and which is connected in parallel with the first voltage divider circuit; a switch section (S2), the switch section being configured to switch between an energized state and an energized disconnected state of the resistor circuit; a control unit (70) which controls the switching of the switch unit, inputs a first voltage division value (Vns1, Vns2) of the first voltage division circuit, and calculates insulation resistance and detects leakage according to the input first voltage division value; and A resistor (R3) has one end connected to a second power path different from the first power path in the power path on the positive side and the power path on the negative side, and the other end connected to the grounding member side. [Structure 12] The leakage detection device as described in structure 11, wherein: A switch (S4) is connected in series with the above resistor. When the input first divided voltage value ( Vns01 , Vns02 ) of the first divided voltage circuit is smaller than a threshold value (Vth), the control unit turns on the switch and conducts electricity between the second power supply path and the ground via the resistor. [Structure 13] The leakage detection device as described in Structure 12 or Structure 13, wherein: The value of the resistance is smaller than the insulation resistance between the second power supply path and the ground and is larger than a value allowed as a normal value of the insulation resistance. 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, wherein the leakage detection device (20) detects leakage between a power path (L1, L2) connected to a terminal of a battery (10) and a grounding member (FG). The leakage detection device comprises: a first voltage dividing circuit (30, 130) having one end connected to the power path side and the other end connected to the grounding member side; a resistance circuit (40) having one end connected to the power path side and the other end connected to the grounding member side, and being connected in parallel with the first voltage dividing circuit; a switch unit (S2) configured to be able to switch between a conductive state and a non-conductive state of the resistance circuit; and a control unit (70) configured to perform switching control on the switch unit, input first voltage division values (Vns1, Vns2) of the first voltage dividing circuit, and calculate an insulation resistance and detect leakage based on the input first voltage division values, wherein the first voltage dividing circuit has a range change circuit (60, 160) for changing the voltage division ratio of the first voltage dividing circuit, and when the first voltage division values (Vns01, Vns02) of the input first voltage dividing circuit are less than a threshold value (Vth), the control unit changes the voltage division ratio of the first voltage dividing circuit through the range change circuit (60, 160) to increase the first voltage division value.

2. The leakage detection device according to claim 1, characterized in that the control unit is configured to perform a first input step, a second input step, and a leakage detection step, wherein in the first input step, when the resistance circuit is in a conductive state, a first voltage division value (Vns1) from the first voltage dividing circuit is input, in the second input step, when the resistance circuit is in a non-conductive state, a first voltage division value (Vns2) from the first voltage dividing circuit is input, and in the leakage detection step, an insulation resistance is calculated and leakage is detected based on the first voltage division value input in the first input step and the first voltage division value input in the second input step, and before performing the first input step or the second input step, the control unit inputs first voltage division values (Vns01, Vns02) of the first voltage dividing circuit, and when the input first voltage division value is less than the threshold value, changes the voltage division ratio of the first voltage dividing circuit.

3. The leakage detection device according to claim 1, characterized in that the resistance circuit is a second voltage dividing circuit, and the control unit is configured to be able to input voltage division values from the first voltage dividing circuit and the second voltage dividing circuit, and perform a first switching step, a first input step, a second switching step, a second input step, a characteristic determination step, and a leakage detection step, wherein in the first switching step, the switch unit is controlled and the second voltage dividing circuit is switched to a conductive state, and in the first input step, after the first switching step, when the second voltage dividing circuit is in a conductive state, a first voltage division value (Vns1) from the first voltage dividing circuit and a second voltage division value (Vrs1) from the second voltage dividing circuit are input, The second switching step is after the first input step, controls the switching unit, and switches the second voltage dividing circuit to a power-on cut-off state. The second input step is after the second switching step. When the second voltage dividing circuit is in the power-on cut-off state, the first divided voltage value (Vns2) from the first voltage dividing circuit is input. The characteristic determination step determines whether an abnormality has occurred in the first voltage dividing circuit and the second voltage dividing circuit based on the first divided voltage value and the second divided voltage value input in the first input step. The leakage detection step calculates the insulation resistance and detects leakage based on the first divided voltage value input in the first input step and the first divided voltage value input in the second input step.

4. The leakage detection device according to any one of claims 1 to 3. Characterized in that The first voltage dividing circuit has a first A detection resistor (Rs1), a first B detection resistor (Rk1'), a first C detection resistor (Rk1), and a voltage division ratio switching switch (S3). The voltage division ratio switching switch is connected in series with the first C detection resistor (Rk1) and switches the power-on state and the power-on cut-off state of the first C detection resistor (Rk1). The series connection body of the first C detection resistor (Rk1) and the voltage division ratio switching switch (S3) is connected in parallel with the first B detection resistor (Rk1') to form a parallel connection body. The first A detection resistor (Rs1) is connected in series with the parallel connection body. The control unit changes the voltage division ratio of the first voltage dividing circuit by switching the voltage division ratio switching switch.

5. The leakage detection device according to any one of claims 1 to 3. Characterized in that The first voltage dividing circuit has a first A detection resistor (Rs1), a first B detection resistor (Rk1'), a first C detection resistor (Rk1), and a voltage division ratio switching switch (S3). The voltage division ratio switching switch is connected in parallel with the first B detection resistor (Rk1') and switches the power-on state and the power-on cut-off state of the first B detection resistor (Rk1'). The first A detection resistor (Rs1), the first B detection resistor (Rk1'), and the first C detection resistor (Rk1) are connected in series. The control unit changes the voltage division ratio of the first voltage dividing circuit by switching the voltage division ratio switching switch.

6. The leakage detection device according to any one of claims 1 to 3. Characterized in that The first voltage dividing circuit has a first A detection resistor (Rs1), a first B detection resistor (Rk1'), and a first C detection resistor (Rk1), and they are connected in series. The control unit normally inputs the first divided voltage value from the connection point (P101) between the first B detection resistor Rk1' and the first C detection resistor Rk1. When the input first divided voltage value is less than the threshold value, the control unit changes the voltage division ratio of the first voltage dividing circuit by inputting the first divided voltage value from the connection point (P102) between the first A detection resistor Rs1 and the first B detection resistor Rk1'.

7. The leakage detection device according to any one of claims 1 to 3. Characterized in that, when the voltages (Vn1, Vn2) across the first voltage dividing circuit calculated based on the first voltage division value and the voltage division ratio input from the first voltage dividing circuit are less than the determination thresholds (TL1, TL2), the control unit detects leakage without calculating the value of the insulation resistance.

8. The leakage detection device according to any one of claims 1 to 3, Characterized in that, in the power supply path, there is a positive electrode side power supply path (L1) connected to the positive electrode terminal of the battery and a negative electrode side power supply path (L2) connected to the negative electrode terminal of the battery, the first voltage dividing circuit and the resistance circuit are connected to a first power supply path which is either the positive electrode side power supply path or the negative electrode side power supply path, a resistor (R3) is provided between the second power supply path different from the first power supply path among the positive electrode side power supply path and the negative electrode side power supply path and the grounding member.

9. The leakage detection device according to claim 8, Characterized in that, a switching switch (S4) is connected in series to the resistor, when the first voltage division values (Vns01, Vns02) of the first voltage dividing circuit input are less than a threshold value (Vth), the control unit turns on the switching switch and energizes between the second power supply path and the grounding member via the resistor.

10. The leakage detection device according to claim 9, Characterized in that, the value of the resistor is smaller than the insulation resistance between the second power supply path and the grounding member and larger than the value allowed as the normal value of the insulation resistance.

11. A leakage detection device, the leakage detection device (20) detects leakage between the positive electrode side power supply path (L1) connected to the positive electrode terminal of the battery (10) and the grounding member (FG) and leakage between the negative electrode side power supply path (L2) connected to the negative electrode terminal of the battery and the grounding member (FG), the leakage detection device comprises: a first voltage dividing circuit (130), one end of the first voltage dividing circuit is connected to a first power supply path which is either the positive electrode side power supply path or the negative electrode side power supply path, and the other end is connected to the grounding member side; a resistance circuit (40), one end of the resistance circuit is connected to the first power supply path side, the other end is connected to the grounding member side, and is connected in parallel with respect to the first voltage dividing circuit; a switch unit (S2), the switch unit is configured to be able to switch the energized state and the energized cut-off state of the resistance circuit; a control unit (70), the control unit performs switching control on the switch unit, inputs the first voltage division values (Vns1, Vns2) of the first voltage dividing circuit, and calculates the insulation resistance and detects leakage according to the input first voltage division values; and a resistor (R3), one end of the resistor is connected to a second power supply path different from the first power supply path among the positive electrode side power supply path and the negative electrode side power supply path, and the other end is connected to the grounding member side.

12. The leakage detection device according to claim 11, Characterized in that, A changeover switch (S4) is connected in series to the resistor. When the first divided voltage values (Vns01, Vns02) of the first voltage dividing circuit input thereto are less than the threshold value (Vth), the control unit turns on the changeover switch and energizes between the second power supply path and the grounding member via the resistor.

13. The leakage detection device according to claim 11 or 12, characterized in that the value of the resistor is smaller than the insulation resistance between the second power supply path and the grounding member and is larger than the value allowed as the normal value of the insulation resistance.

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