WO2021246225A1 - Electric leakage detection device - Google Patents

Abstract

This electric leakage detection device (20) comprises: measurement units (21, 22) which are configured so that a resistor is selectively connectable between the reference potential (GND) and one among a positive electrode-side power supply path (L10) and a negative electrode-side power supply path (L20) and which measure the voltage of each power supply path in a state in which the resistor is connected; and a detection unit (23) the detects electric leakage on the basis of the measurement results from the measurement units. The measurement units measure the voltage in a parallel connection state in which batteries (Vc1, Vc2) are connected in parallel to the power supply path by switch units (RY1, RY2, RY4, and RY5) and measure the voltage in an individual connection state in which the batteries are individually connected by the switching units. The detection unit detects whether or not any one of the power supply paths and electric paths (L11, L12, L21, L22) is leaking, on the basis of the measurement result in the parallel connection state and the measurement result in the individual connection state.

Description

Leakage detector Cross-reference of related applications

This application is based on Japanese Application No. 2020-997523 filed on June 4, 2020, and the contents of the description are incorporated herein by reference.

The disclosure of this application relates to an earth leakage detection device.

Conventionally, as a power supply system mounted on a vehicle, a system in which a series connection and a parallel connection of a plurality of assembled batteries can be changed has been proposed (for example, Patent Document 1). According to the power supply system described in Patent Document 1, it is possible to suppress heat generation during charging while enabling charging with a large voltage.

By the way, in the power supply system mounted on the vehicle, an insulation resistance detection circuit is generally adopted in order to detect an electric leakage. As the insulation resistance detection circuit, for example, as shown in Patent Documents 2 to 4, a resistance voltage dividing type insulation resistance detection circuit is known. When this resistance voltage divider type insulation resistance detection circuit is adopted, even if the number of electrical equipment in the vehicle increases and the stray capacitance between the assembled battery and the ground (chassis, etc.) increases, the detection accuracy will be affected. Can be suppressed.

Japanese Unexamined Patent Publication No. 2019-118221 Japanese Unexamined Patent Publication No. 2003-66090 Japanese Patent No. 5861954 Japanese Patent No. 4785627

By the way, in a power supply system in which series connection and parallel connection can be changed as described in Patent Document 1, when an insulation resistance detection circuit of a resistance voltage division method is adopted, the combined insulation resistance in the entire connection path is measured. can do. However, although it is possible to detect that an electric leakage occurs in one of the connection paths based on the synthetic insulation resistance, it is not possible to specify in which of the connection paths the electric leakage occurs.

The present disclosure has been made to solve the above-mentioned problems, and an object thereof is to provide an earth leakage detection device capable of detecting an earth leakage for each route.

The means for solving the above problems are a plurality of batteries, a first electric path provided for each of the batteries, one end of which is connected to a positive terminal of the battery, and a first electric path of each of the first electric paths. A power path on the positive side to which the other end is connected, a second electric path provided for each battery and one end connected to the negative terminal of the battery, and the other end of each of the second electric paths. It is applied to a power supply system having a power supply path on the negative side to which is connected, and a switch unit provided between each electric path and each power path and switching between energization and de-energization, respectively. In a leakage detector that detects a decrease in insulation resistance between the system and an isolated reference potential, a resistor is selected between the reference potential and either the power path on the positive side or the power path on the negative side. It is configured to be connectable, and includes a measuring unit that measures the voltage of each power supply path in a state where the resistor is connected, and a detecting unit that detects electric leakage based on the measurement result from the measuring unit. The measuring unit measures the voltage in a parallel connection state in which the batteries are connected in parallel by the switch unit to the power supply path, and each battery is individually connected by the switch unit for each battery. The detector measures the voltage in the individually connected state connected to, and the detection unit leaks electricity in either the power supply path or the electric path based on the measurement result in the parallel connection state and the measurement result in the individual connection state. Detect if it is done.

The measuring unit measures the voltage in the parallel connection state and measures the voltage in the individual connection state, and the detection unit measures each power supply path and each electricity based on the measurement result in the parallel connection state and the measurement result in the individual connection state. Detects which route is leaking. Therefore, it is possible to identify the leaking path and easily perform work such as replacement.

The above objectives and other objectives, features and advantages of the present disclosure will be further clarified by the following detailed description with reference to the accompanying drawings. The drawing is
FIG. 1 is a circuit diagram of a power supply system. FIG. 2 is a circuit diagram of a power supply system in a comparative example. FIG. 3 is a circuit diagram of a power supply system in a comparative example. FIG. 4 is a circuit diagram of the power supply system in the comparative example. FIG. 5 is a circuit diagram of a power supply system in a series connection state. FIG. 6 is a flowchart showing the main routine. FIG. 7 is a flowchart showing the total insulation resistance measurement process. FIG. 8 is a flowchart showing the insulation resistance Rpa2 and Rna2 measurement processing. FIG. 9 is a flowchart showing the insulation resistance Rpa3 and Rna3 measurement processing. FIG. 10 is a circuit diagram of a power supply system in an individual connection state. FIG. 11 is a circuit diagram of a power supply system in an individual connection state. FIG. 12 is a circuit diagram of a power supply system in a modified example. FIG. 13 is a circuit diagram of a power supply system in a modified example.

Hereinafter, the first embodiment in which the "leakage detection device" is applied to the power supply system of a vehicle (for example, a hybrid vehicle or an electric vehicle) will be described with reference to the drawings. In the following, the same or equal parts of the embodiments and variations thereof are designated by the same reference numerals, and the description thereof will be incorporated for the parts having the same reference numerals.

The power supply system 10 includes a plurality of assembled batteries Vc1 and Vc2, an earth leakage detection device 20, and a charger 30. The assembled batteries Vc1 and Vc2 are batteries having a terminal voltage of, for example, 100 V or more, and are configured by connecting a plurality of battery cells in series. As the battery cell, for example, a lithium ion storage battery or a nickel hydrogen storage battery can be used.

Further, the power supply system 10 is provided for each of the assembled batteries Vc1 and Vc2, and has electric paths L11 and L12 as a first electric path in which one end is connected to the positive electrode side terminal of the assembled batteries Vc1 and Vc2. Further, the power supply system 10 has a positive electrode side power supply path L10 as a positive electrode side power supply path to which the other ends of the respective electric paths L11 and L12 are connected. A positive electrode side terminal of an electric load (not shown) is connected to the positive electrode side power supply path L10.

The positive electrode side power supply path L10 is composed of a conductive member such as a bus bar, and is insulated from a ground GND (chassis ground such as a vehicle body, body GND) which is a reference potential. That is, the positive electrode side power supply path L10 is grounded via the insulation resistor Rp1. Similarly, each of the electric paths L11 and L12 is composed of a conductive member and is grounded via insulating resistors Rp3 and Rp2, respectively.

Similarly, the power supply system 10 is provided for each of the assembled batteries Vc1 and Vc2, and has electric paths L21 and L22 as a second electric path in which one end is connected to the negative electrode side terminal of the assembled batteries Vc1 and Vc2. Further, the power supply system 10 has a negative electrode side power supply path L20 as a negative electrode side power supply path to which the other ends of the respective electric paths L21 and L22 are connected. A negative electrode side terminal of an electric load (not shown) is connected to the negative electrode side power supply path L20.

The negative electrode side power supply path L20 is composed of a conductive member such as a bus bar, and is insulated from the ground GND. That is, the negative electrode side power supply path L20 is grounded via the insulation resistor Rn1. Similarly, each of the electric paths L21 and L22 is composed of a conductive member, and is grounded via insulating resistors Rn3 and Rn2, respectively.

The positive electrode side power supply path L10 and the negative electrode side power supply path L20 are each connected to an electric load via a relay switch SMR (system main relay switch) (not shown), and the relay switch SMR can switch between energization and energization cutoff. Has been done.

Further, between the power supply paths L10 and L20 and the respective electric paths L11, L12, L21, and L22, relays RY1, RY2, RY4, and RY5 are provided as relay switches for switching between energization and energization cutoff. These relays RY1, RY2, RY4, RY5 correspond to the switch unit.

Then, the power supply system 10 has an electric path L30 as a third electric path for connecting the assembled batteries Vc1 and Vc2 in series. One end of the electric path L30 is connected to the electric path L11 (to the side of the assembled battery Vc1 from the relay RY1), and the other end is connected to the electric path L22 (to the side of the assembled battery Vc2 from the relay RY5). ing. The electric path L30 is provided with a relay RY3 as a series connection switch unit for switching the energization and the energization cutoff of the electric path L30.

The positive electrode side terminal of the charger 30 is connected to the electric path L12 connected to the positive electrode side terminal of the assembled battery Vc2 which is the end in the series connection state among the electric paths L11 and L12. Similarly, the negative electrode side terminal of the charger 30 is connected to the electric path L21 connected to the negative electrode side terminal of the assembled battery Vc1 which is the end portion of the electric paths L21 and L22 in the series connection state. The positive electrode side terminal of the charger 30 is connected to the electric path L12 via the switch SW5, and the negative electrode side terminal thereof is connected to the electric path L21 via the switch SW6.

Next, the leakage detection device 20 will be described. The leakage detection device 20 includes a voltage dividing circuit 21, an A / D converter 22, and a control unit 23. The voltage dividing circuit 21 has a series connection body of the detection resistor R1 and the detection resistance R2 as a resistor, and one end of the series connection body is connected to the ground GND (body GND). The other end of the series connection body is configured to be selectively connectable to either the positive electrode side power supply path L10 or the negative electrode side power supply path L20. That is, the other end of the series connection body is connected to the positive electrode side power supply path L10 via the switch SW1 and is connected to the negative electrode side power supply path L20 via the switch SW4.

One end of the A / D converter 22 is connected to the connection point P1 between the detection resistor R1 and the detection resistor R2, and the other end is connected to the ground GND (body GND). The A / D converter 22 is a device that inputs a voltage (analog signal) between the detection resistor R1 and the detection resistor R2, converts it into a digital signal, and outputs the voltage. A control unit 23 is connected to the A / D converter 22. The voltage divider circuit 21 and the A / D converter 22 correspond to the measuring unit.

The control unit 23 is mainly composed of a microcomputer equipped with a CPU, ROM, RAM, I / O, etc., and the CPU realizes various functions by executing a program stored in the ROM. The various functions may be realized by electronic circuits that are hardware, or at least a part of them may be realized by software, that is, processing executed on a computer. The control unit 23 has a function of controlling the on / off state of each switch and each relay included in the power supply system 10, a function of detecting an electric leakage of the power supply system 10, and the like. In addition to the control unit 23, a control device having a function of controlling the on / off state of various switches may be provided, and the leakage may be detected in cooperation with the leakage detection device 20.

By configuring such a power supply system 10, it is possible to supply electric power to an electric load with the assembled batteries Vc1 and Vc2 connected in parallel, and to connect the assembled batteries Vc1 and Vc2 in series during charging. can. As a result, the amount of current can be reduced during charging and heat generation can be suppressed.

By the way, in the power supply system 10 having the circuit configuration as described above and switching between series connection and parallel connection depending on the situation, when detecting the leakage, the leakage detection device is used, for example, the leakage detection shown in the comparative example of FIG. It is conceivable to have a configuration like the device 201. In the leakage detection device 201 shown in the comparative example of FIG. 2, unlike the leakage detection device 20 shown in FIG. 1, the voltage dividing circuit 21 (one end of the series connection body) is connected to the electric path L12 via the switch SW2. .. Further, in the leakage detection device 201 shown in the comparative example of FIG. 2, the voltage dividing circuit 21 is connected to the electric path L21 via the switch SW3.

In the leakage detection device 201 of FIG. 2, when power is supplied by the assembled batteries Vc1 and Vc2 in the parallel connection state as shown in FIG. 3, the leakage can be detected by controlling the switches SW1 and SW4 on and off. can. Further, in the leakage detection device 201 of FIG. 2, when the assembled batteries Vc1 and Vc2 in the series connection state are charged as shown in FIG. 4, the leakage can be detected by controlling the switches SW3 and SW4 on and off. can.

However, the above-mentioned leakage detection method has the following problems. That is, in the power supply system 10 configured so that the series connection and the parallel connection can be changed, a large number of relays are provided, and the positive electrode side power supply path L10 and the electric paths L11 and L12 are configured by different parts (bus bars, etc.). Has been done. Therefore, the positive electrode side power supply path L10 and the electric paths L11 and L12 are configured to be individually replaceable. The same applies to the negative electrode side.

On the other hand, as shown in FIG. 3, when power is supplied while the assembled batteries Vc1 and Vc2 are connected in parallel, the leakage detection device 20 can detect that leakage is occurring on either the positive electrode side or the negative electrode side. , Power path L10, L20, and electric path L11, L12, L21, L22, it is not possible to determine from which path the electric leakage occurs.

That is, when the insulation resistance is calculated in the state of FIG. 3, the parallel composite values of the insulation resistances Rp1, Rp2, and Rp3 can be calculated on the positive electrode side, but the insulation resistances Rp1, Rp2, and Rp3 are calculated individually. I couldn't. Similarly, on the negative electrode side, the parallel composite value of the insulation resistances Rn1, Rn2, and Rn3 could be calculated, but the insulation resistances Rn1, Rn2, and Rn3 could not be calculated individually. Therefore, when an electric leakage is detected, it is necessary to replace all the routes on the positive electrode side or the entire negative electrode side, or the operator or the like disassembles the parts one by one and inspects them.

Further, when the insulation resistance is calculated in the charged state (series connection state) shown in FIG. 4, the insulation resistance Rp1 cannot be detected on the positive electrode side, and the insulation resistance Rn1 cannot be detected on the negative electrode side. As a result, there is a problem that leakage in the power supply paths L10 and L20 cannot be detected during charging.

Therefore, the leakage detection device 20 of the present embodiment calculates the insulation resistance for each path by executing the following processing, and specifies which path the leakage is in based on each insulation resistance. is doing. Hereinafter, it will be described in detail.

First, a method for determining whether or not there is an electric leakage in any of the entire routes will be described. When power is supplied by the assembled batteries Vc1 and Vc2 in the parallel connection state, the control unit 23 controls the on / off of the switches SW1 and SW4 so that the insulation resistances Rp1 and Rp2 on the positive electrode side are supplied. The parallel composite value of Rp3 is calculated, and the parallel composite value of the insulation resistors Rp1, Rp2, and Rp3 is calculated on the negative electrode side.

Specifically, the control unit 23 sets the switch SW1 to the ON state, and the voltage division value (voltage division value) at the connection point P1 between the detection resistor R1 and the detection resistor R2 via the voltage divider circuit 21 and the A / D converter 22. Voltage) is input. Similarly, the control unit 23 turns on the switch SW4 and inputs the voltage dividing value at the connection point P1 between the detection resistor R1 and the detection resistor R2 via the voltage divider circuit 21 and the A / D converter 22.

Then, the control unit 23 has the insulation resistances Rp1, Rp2, Rp3 on the positive electrode side in parallel and the insulation on the negative electrode side based on the input voltage dividing value, the voltage dividing ratio, and the voltages of the assembled batteries Vc1 and Vc2. The parallel combined value of the resistors Rn1, Rn2, and Rn3 is calculated. Then, the leakage detection device 20 detects whether or not an leakage has occurred in any of the paths of the power supply system 10 based on the calculated parallel composite value. The value of the voltage division ratio is known, and the voltages of the assembled batteries Vc1 and Vc2 may be obtained from a battery monitoring device (not shown) for monitoring the state of the assembled batteries Vc1 and Vc2. Further, the voltage may be estimated from the charged state of the assembled batteries Vc1 and Vc2. The method for calculating the parallel composite value is the same as the conventional method described in the prior art (Patent Documents 2 to 4, etc.) and is well known, so the description thereof will be omitted.

Next, we will explain how to detect an electric leakage during charging. As shown in FIG. 5, when the switches SW5, SW6 and the relay RY3 are turned on and the assembled batteries Vc1 and Vc2 in the series connection state are charged, the relays RY2 and RY4 are set by the control unit 23 of the leakage detection device 20. It is turned on. As a result, current flows in all paths, as shown by the region surrounded by the alternate long and short dash line in FIG. That is, current flows in any of the power supply paths L10, L20 and the electric paths L11, L12, L21, and L22.

In this state, the control unit 23 sets the insulation resistances Rp1, Rp2, Rp3 based on the voltage dividing value acquired by turning on the switch SW1 and the voltage dividing value acquired by turning on the switch SW4. And the combined value of the insulation resistances Rn1, Rn2, Rn3 are calculated. Then, the leakage detection device 20 detects whether or not there is a leakage in any path of the power supply system 10 based on the calculated combined value.

From the above, it is possible to detect an electric leakage in any path of the power supply system 10 both when the electric power is supplied and when the electric power is charged.

Next, when an electric leakage in any path of the power supply system 10 is detected, the control unit 23 executes the main routine shown in FIG. When the main routine is started, first, the control unit 23 executes the total insulation resistance measurement process shown in FIG. 7 (step S101).

In the total insulation resistance measurement process, the control unit 23 turns on the relays RY1, RY2, RY4, and RY5, and switches the relay RY3 to the off state (step S201). Next, the control unit 23 turns on the switch SW1 (step S202). Then, the control unit 23 detects (measures) the voltage dividing value V1 at the connection point P1 via the voltage dividing circuit 21 and the A / D converter 22 (step S203).

Next, the control unit 23 puts the switch SW1 in the off state (step S204) and puts the switch SW4 in the on state (step S205). Then, the control unit 23 detects (measures) the voltage dividing value V4 at the connection point P1 via the voltage dividing circuit 21 and the A / D converter 22 (step S206), and turns off the switch SW4 (step). S207).

Next, the control unit 23 calculates the insulation resistance values Rp and Rn based on the partial pressure values V1 and V4 in the same manner as described above (step S208). The insulation resistance value Rp calculated in step S208 is a parallel composite value of the insulation resistances Rp1, Rp2, and Rp3. The insulation resistance value Rn calculated in step S208 is a parallel combined value of the insulation resistances Rn1, Rn2, and Rn3. Then, the control unit 23 turns off the relays RY1, RY2, RY4, and RY5 (step S20), ends the total insulation resistance measurement process, and proceeds to step S102 of the main routine.

After that, the control unit 23 stores the insulation resistance values Rp and Rn calculated in step S208 as the insulation resistance values Rpa and Rna, respectively. That is, as expressed by mathematical formulas (1) and (2), the insulation resistance value Rpa stores the parallel combined value of the insulation resistances Rp1, Rp2, Rp3, and the insulation resistance value Rna is the insulation resistance Rn1, Rn2, Rn3. The parallel composite value of is stored.

Then, the control unit 23 executes the insulation resistance Rpa2 and Rna2 measurement processes shown in FIG. 8 (step S103). In the insulation resistance Rpa2, Rna2 measurement process, the control unit 23 turns on the relays RY2 and RY5 and switches the relays RY1, RY3 and RY4 to the off state (step S301). As a result, as shown in FIG. 10, a current flows through the power supply paths L10 and L20 and the electric paths L12 and L22. That is, only the assembled battery Vc2 is in an individual connection state in which it is individually connected to the power supply paths L10 and L20.

Next, the control unit 23 turns on the switch SW1 (step S302), and detects (measures) the voltage dividing value V1 at the connection point P1 via the voltage dividing circuit 21 and the A / D converter 22 (step). S303). Next, the control unit 23 turns the switch SW1 into an off state (step S304) and turns the switch SW4 into an on state (step S305). Then, the control unit 23 detects (measures) the voltage dividing value V4 at the connection point P1 via the voltage dividing circuit 21 and the A / D converter 22 (step S306), and turns off the switch SW4 (step). S307).

Next, the control unit 23 calculates the insulation resistance values Rp and Rn based on the partial pressure values V1 and V4 (step S308). The insulation resistance value Rp calculated in step S308 is a parallel composite value of the insulation resistances Rp1 and Rp2. Further, the insulation resistance value Rn calculated in step S308 is a parallel combined value of the insulation resistances Rn1 and Rn2. Then, the control unit 23 turns off the relays RY2 and RY5 (step S309), ends the insulation resistance Rpa2, Rna2 measurement process, and proceeds to step S104 of the main routine.

After that, the control unit 23 stores the insulation resistance values Rp and Rn calculated in step S308 as the insulation resistance values Rpa2 and Rna2, respectively (step S104). That is, as expressed by mathematical formulas (3) and (4), the insulation resistance value Rpa2 stores the parallel composite value of the insulation resistances Rp1 and Rp2, and the insulation resistance value Rna2 is the parallel composite value of the insulation resistances Rn1 and Rn2. Is remembered.

Then, the control unit 23 executes the insulation resistance Rpa3 and Rna3 measurement processes shown in FIG. 9 (step S105). In the insulation resistance Rpa3, Rna3 measurement process, the control unit 23 turns on the relays RY1 and RY4 and switches the relays RY2, RY3 and RY5 to the off state (step S401). As a result, as shown in FIG. 11, a current flows through the power supply paths L10 and L20 and the electric paths L11 and L21. That is, only the assembled battery Vc1 is in an individual connection state in which it is individually connected to the power supply paths L10 and L20.

Next, the control unit 23 turns on the switch SW1 (step S402), and detects (measures) the voltage dividing value V1 at the connection point P1 via the voltage dividing circuit 21 and the A / D converter 22 (step). S403). Next, the control unit 23 turns the switch SW1 into an off state (step S404) and turns the switch SW4 into an on state (step S405). Then, the control unit 23 detects the voltage dividing value V4 at the connection point P1 via the voltage dividing circuit 21 (step S406), and turns the switch SW4 into an off state (step S407).

Next, the control unit 23 calculates the insulation resistance values Rp and Rn based on the partial pressure values V1 and V4 (step S408). The insulation resistance value Rp calculated in step S408 is a parallel composite value of the insulation resistances Rp1 and Rp3. The insulation resistance value Rn calculated in step S408 is a parallel combined value of the insulation resistances Rn1 and Rn3. Then, the control unit 23 turns off the relays RY1 and RY4 (step S409), ends the insulation resistance Rpa3 and Rna3 measurement processing, and proceeds to step S106 of the main routine.

After that, the control unit 23 stores the insulation resistance values Rp and Rn calculated in step S408 as the insulation resistance values Rpa3 and Rna3, respectively. That is, as expressed by mathematical formulas (5) and (6), the insulation resistance value Rpa3 stores the parallel composite value of the insulation resistances Rp1 and Rp3, and the insulation resistance value Rna3 is the parallel composite value of the insulation resistances Rn1 and Rn3. Is remembered.

Then, the control unit 23 calculates each insulation resistance Rp1, Rp2, Rp3, Rn1, Rn2, Rn3 by solving the equations (1) to (6) (step S107). Specifically, as shown in the mathematical formulas (7) to (12), each insulation resistance Rp1, Rp2, Rp3, Rn1, Rn2, Rn3 is calculated.

After the end of step S107, the control unit 23 ends the main routine, and as a result of executing the main routine, leakage occurs in any of the paths based on each insulation resistance Rp1, Rp2, Rp3, Rn1, Rn2, Rn3 calculated. Detect if you are doing it. Specifically, the control unit 23 compares each insulation resistance Rp1, Rp2, Rp3, Rn1, Rn2, Rn3 with the threshold value, and the insulation resistance Rp1, Rp2, Rp3, Rn1, Rn2 whose value is smaller than the threshold value. Identify Rn3. Then, the control unit 23 detects that an electric leakage occurs in the path corresponding to (connected) the specified insulation resistances Rp1, Rp2, Rp3, Rn1, Rn2, and Rn3. As described above, the control unit 23 of the present embodiment corresponds to the detection unit and the calculation unit.

According to the configuration of the above embodiment, it has the following effects.

The A / D converter 22 measures the voltage in the parallel connection state of the assembled batteries Vc1 and Vc2 via the voltage dividing circuit 21, and also measures the voltage in the individually connected state for each of the assembled batteries Vc1 and Vc2. The control unit 23 leaks electricity in any of the power supply paths L10, L20 and each electric path L11, L12, L21, L22 based on the measurement result (partial pressure value) in the parallel connection state and the measurement result in the individual connection state. Is detected. Therefore, it is possible to identify the leaking path and easily perform work such as replacement.

Further, the control unit 23 specified the insulation resistances Rp1, Rp2, Rp3, Rn1, Rn2, and Rn3, respectively, based on the pressure division value in the parallel connection state and the pressure division value in the individual connection state. Thereby, it is possible to accurately determine whether each insulation resistance Rp1, Rp2, Rp3, Rn1, Rn2, Rn3 is lower than a predetermined threshold value.

The charger 30 charges the assembled batteries Vc1 and Vc2 when the assembled batteries Vc1 and Vc2 are connected in series by the relay RY3. Therefore, it is possible to enable quick charging and suppress heat generation.

Further, when the charger 30 charges the assembled batteries Vc1 and Vc2, the relays RY2 and RY4 provided between the electric paths L12 and L21 to which the charger 30 is connected and the power supply paths L10 and L20 are turned on. Switch to. Then, the A / D converter 22 measures the voltage dividing value of the voltage in each of the power supply paths L10 and L20 at the time of charging via the voltage dividing circuit 21. The control unit 23 detects that any one of the power supply paths L10 and L20 and the electric paths L11, L12, L21, and L22 is leaking based on the voltage division value measured at the time of charging. Therefore, even when charging in a series connection state, the control unit 23 can detect whether or not there is an electric leakage at any point, and can quickly detect an abnormality.

Further, since the relays RY2 and RY4 are switched to the ON state during charging, it is not necessary to provide the switches SW2 and SW3 as shown in the comparative example of FIG. 2, and the circuit configuration can be simplified.

When power is supplied to the electric load from the power supply system 10, the assembled batteries Vc1 and Vc2 are connected in parallel. Then, in this state, the A / D converter 22 measures the voltage dividing value of the voltage in each of the power supply paths L10 and L20 via the voltage dividing circuit 21, and the control unit 23 sets the measured voltage dividing value. Based on this, it is detected that any one of the power supply paths L10 and L20 and the electric paths L11, L12, L21, and L22 is leaking. Therefore, even when power is supplied in a parallel connection state, the control unit 23 can detect whether or not there is an electric leakage at any point, and can quickly detect an abnormality. ..

(Modified example of the above embodiment)
-In the power supply system 10 of the above embodiment, two assembled batteries Vc1 and Vc2 are adopted, but three or more assembled batteries may be adopted. At that time, it is necessary to configure the three or more assembled batteries so as to be switchable between the series connection state and the parallel connection state, and to switch each set battery to the individual connection state for the power supply paths L10 and L20. ..

-In the above embodiment, the control unit 23 has calculated the insulation resistances Rp1, Rp2, Rp3, Rn1, Rn2, Rn3, but the detected combined resistance values (Rpa, Rpa2, Rpa3, Rna, Rna2, Rna3) are used. Based on this, the path of leakage (decreased insulation resistance) may be specified. As a result, the amount of calculation can be reduced.

-In the above embodiment, the charger 30 is connected to the electric paths L12 and L21, but the charger 30 may be connected to the power supply paths L10 and L20.

-In the above embodiment, the control unit 23 executes the main routine when an electric leakage occurs at any of the locations, but the main routine is executed every predetermined cycle even if the electric leakage is not detected at any of the locations. May be executed. Further, it may be executed at a predetermined timing (for example, when the power supply system 10 is started). As a result, it is possible to detect the leakage and identify the path of the leakage.

-In the above embodiment, when charging only one of the assembled batteries Vc1 and Vc2, the relays RY1, RY2, RY4, and RY5 are controlled as shown in FIGS. 12 or 13, and the minute at the connection point P1. The pressure value may be measured (detected). That is, when charging only the assembled battery Vc1, as shown in FIG. 12, the control unit 23 turns on the switches SW5 and SW6 and the relays RY1, RY2 and RY4. As a result, as shown by the region surrounded by the alternate long and short dash line in FIG. 12, current flows in all the paths. That is, current flows in any of the power supply paths L10, L20 and the electric paths L11, L12, L21, and L22. In this state, by controlling the on / off of the switches SW1 and SW4, the control unit 23 calculates the parallel composite value of the insulation resistances Rp1, Rp2, Rp3 on the positive electrode side, and the insulation resistances Rp1, Rp2, on the negative electrode side. The parallel composite value of Rp3 is calculated. Then, the control unit 23 detects an electric leakage in any path of the power supply system 10 based on the calculated parallel composite value.

Further, when charging only the assembled battery Vc2, as shown in FIG. 13, the control unit 23 turns on the switches SW5 and SW6 and the relays RY2, RY3 and RY4. As a result, current flows in all paths, as shown by the region surrounded by the alternate long and short dash line in FIG. That is, current flows in any of the power supply paths L10, L20 and the electric paths L11, L12, L21, and L22. In this state, by controlling the on / off of the switches SW1 and SW4, the control unit 23 calculates the parallel composite value of the insulation resistances Rp1, Rp2, Rp3 on the positive electrode side, and the insulation resistances Rp1, Rp2, on the negative electrode side. The parallel composite value of Rp3 is calculated. Then, the control unit 23 detects an electric leakage in any path of the power supply system 10 based on the calculated parallel composite value.

Although the present disclosure has been described in accordance with the examples, it is understood that the present disclosure is not limited to the examples and structures. The present disclosure also includes various variations and variations within a uniform range. In addition, various combinations and forms, as well as other combinations and forms that include only one element, more, or less, are within the scope and scope of the present disclosure.

Claims (5)

1. A plurality of batteries (Vc1, Vc2), a first electric path (L11, L12) provided for each of the batteries and one end of which is connected to a positive terminal of the battery, and a first electric path of each of the first electric paths. A power path (L10) on the positive side to which the other end is connected, a second electric path (L21, L22) provided for each battery and one end connected to a terminal on the negative side of the battery, and each of the above. A switch unit (L20) on the negative side to which the other end of the second electric path is connected, and a switch unit (L20) provided between each electric path and each power path, and switching between energization and energization cutoff, respectively. RY1, RY2, RY4, RY5), which is applied to a power supply system (10) and detects a decrease in insulation resistance between the power supply system and an isolated reference potential (GND) (20). In
   A resistor is configured to be selectively connectable between either the power supply path on the positive electrode side or the power supply path on the negative electrode side and the reference potential, and the voltage of each power supply path is connected to the resistor. Measuring unit (21, 22) to measure
   A detection unit (23) for detecting an electric leakage based on the measurement result from the measurement unit is provided.
   The measuring unit measures the voltage in a parallel connection state in which the batteries are connected in parallel by the switch unit to the power supply path, and each battery is individually connected by the switch unit for each battery. Measure the voltage in the connected individual connection state,
   The detection unit is an electric leakage detection device that detects whether an electric leakage occurs in each power supply path or each electric path based on the measurement result in the parallel connection state and the measurement result in the individual connection state.
2. A calculation unit (23) for calculating insulation resistance based on the measurement result from the measurement unit is provided.
   The arithmetic unit calculates the insulation resistance of each power supply path and the insulation resistance of each electric path based on the measurement result in the parallel connection state and the measurement result in the individual connection state.
   The electric leakage detection device according to claim 1, wherein the detection unit detects whether an electric leakage occurs in each of the power supply paths or the electric paths based on the insulation resistance calculated by the calculation unit.
3. The power supply system
   A third electric path (L30) connecting the batteries in series, and
   A series connection switch unit (RY3) that switches between energization and de-energization of the third electric path, and
   A charger (30) for charging the battery is provided.
   The leakage detection according to claim 1 or 2, wherein the charger is configured to be able to charge the batteries when the batteries are connected in series by the series connection switch unit. Device.
4. The charger is connected to the electric path connected to the positive electrode side terminal or the negative electrode side terminal of the battery, which is an end portion in the series connection state, among the first electric path and the second electric path. And
   When the charger charges the battery, the electric path provided between the electric path to which the charger is connected and the power supply path among the first electric path and the second electric path. The switch part is switched to the energized state,
   The measuring unit measures the voltage of each power supply path at the time of charging.
   The leakage detection device according to claim 3, wherein the detection unit detects that one of the power supply path and the electric path is leaking based on the measurement result of the voltage measured at the time of charging. ..
5. When an electric load is connected to the power path and power is supplied to the electric load from the power system, the battery is placed in the parallel connection state.
   The measuring unit measures the voltage of each power supply path in the parallel connection state, and measures the voltage.
   The detection unit detects that one of the power supply path and the electric path is leaking based on the measurement result of the voltage measured in the parallel connection state, according to claims 1 to 4. The leakage detection device according to any one of the above.

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