JP2015215163A - Electric leakage detection circuit, battery circuit board, and battery power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric leakage detection circuit that offers improved reliability in detection of faults in a signal path from the electric leakage detection circuit to a battery, a battery circuit board, and a battery power supply device.SOLUTION: An electric leakage detection circuit 3 detects electric leakage between a chassis ground G and a battery B insulated from the chassis ground G. An electric leakage detection circuit 3 includes; a detection signal supply unit 31 which supplies a detection signal TS to a negative terminal B(-); a signal path that directs the detection signal TS supplied from the detection signal supply unit 31 to the negative terminal B(-); a voltage detection unit 32 which detects voltage at a connection point P1 in the signal path as a detection voltage Vd; an electric leakage determination processing unit 343 which determines the presence of electric leakage based on the detection voltage Vd; and a switching unit 33 which switches to provide or cut off continuity between a positive terminal B(+) and the chassis ground G.

Description

  The present invention relates to a leakage detection circuit for detecting leakage of a battery insulated from a ground, a battery circuit board including the leakage detection circuit, and a battery power supply apparatus using the battery as a power source.

  In recent years, hybrid vehicles (HEV: Hybrid Electric Vehicle) using both an engine and an electric motor are widely used, and the use of electric vehicles (EV: Electric Vehicle) is also expanding. Such a vehicle using an electric motor as a power source includes a battery that outputs a high voltage, for example, a voltage of about 288V to 600V, as a power source for driving the motor. Such a battery is configured as an assembled battery in which a plurality of secondary batteries such as a lithium ion secondary battery and a nickel hydride secondary battery are connected in series.

  Such batteries, motors and inverters to which power supply voltage is supplied from the batteries, and high voltage circuits that are circuits connected to the battery, such as wiring for distributing the power supply voltage to these, are insulated from the vehicle body. Yes. Thereby, it has the structure which prevents that the user who touched the vehicle body receives an electric shock.

  In addition, for example, a 12V lead-acid battery has a low voltage in order to supply a power supply voltage to electric devices such as in-vehicle stereos, lighting, car navigation devices, and other devices that operate at a low voltage such as an ECU (Electronic Control Unit). It is mounted on the vehicle as a power source. The vehicle body is a circuit ground of a low voltage circuit such as an electric device or an ECU to which a power supply voltage is supplied from the low voltage power source. That is, the vehicle body is a circuit ground of a low voltage circuit, so-called chassis ground, and the battery is insulated from the chassis ground.

  However, when the insulation resistance between the battery and the chassis ground decreases, a so-called leakage occurs in which a current flows from the battery to the chassis ground. Therefore, conventionally, a leakage detection circuit for detecting leakage of a battery is known (see, for example, Patent Documents 1 and 2).

  However, when such a leakage detection circuit fails, it is not possible to detect the leakage. Therefore, a failure detection circuit that detects a failure in the leakage detection circuit is known (for example, see Patent Document 3).

JP 2009-93822 A JP 2008-304290 A JP 2009-81964 A

  However, conventionally, there has been a disadvantage that a failure in the wiring path from the leakage detection circuit to the battery cannot be sufficiently detected.

  An object of the present invention is to provide a leakage detection circuit, a battery circuit board, and a battery power supply device that can improve the certainty of detecting a failure in a signal path from the leakage detection circuit to the battery.

  The leakage detection circuit according to the present invention is a leakage detection circuit that detects a leakage between a ground and a battery that is insulated from the ground, and that supplies a predetermined inspection signal to one of the electrodes of the battery. A signal supply unit; a signal path for guiding the inspection signal supplied from the inspection signal supply unit to one pole of the battery; a voltage detection unit for detecting a voltage of the signal path as a detection voltage; and the detection voltage A leakage determination processing unit that determines whether or not the leakage has occurred, and a switching unit that switches the presence or absence of conduction between the other electrode of the battery and the ground.

  According to this configuration, the predetermined inspection signal is supplied to the one electrode of the battery via the signal path by the inspection signal supply unit. Then, if a leakage occurs and the resistance value of the leakage resistance between one of the battery poles and the ground decreases, the signal path is connected to the ground via the leakage resistance. The voltage changes. The voltage of this signal path is detected as a detection voltage by the voltage detector. Therefore, when leakage occurs, the detected voltage changes, and thus the leakage determination processing unit can determine whether leakage has occurred based on the detected voltage. And since the internal resistance of the battery is small, when the other part of the battery is connected to the ground by the switching unit, the signal path connected to the one of the battery is connected to the ground via the internal resistance of the battery. Conducted. As a result, a pseudo-leakage state is established, and in this state, if it is determined that the leakage has occurred by the leakage determination processing unit, it can be determined that the leakage detection circuit is operating normally, and the leakage determination process If it is not determined that the leakage has occurred by the unit, it can be determined that the leakage detection circuit has failed.

  And if the switching unit is connected between one of the battery poles on the signal path and the inspection signal supply unit, the switching unit determines whether or not there is conduction between the one electrode of the battery and the ground. In the case of a switching configuration, when a disconnection failure occurs on one pole side of the battery (for example, a position closest to one of the battery poles) from the connection point between the switching unit and the signal path, the switching unit causes one pole of the battery to The leakage detection circuit is operating normally even though the leakage detection circuit is broken. It may look like this.

  However, in the leakage detection circuit according to the present invention, the switching unit conducts between the other electrode of the battery and the ground, thereby connecting the signal path connected to the one electrode of the battery via the internal resistance of the battery. Is connected to ground. Therefore, if one electrode of the battery is not electrically connected to the signal path, the signal path is not electrically connected to the ground even when the switching unit conducts the other electrode of the battery and the ground. As a result, when the signal path is disconnected at a position closest to one of the battery poles, the signal path and the ground are not connected even if the switching unit connects the other battery pole to the ground. , Pseudo-leakage does not occur. Therefore, the leakage determination processing unit does not determine that a leakage has occurred. Accordingly, it is possible to improve the reliability of detecting a failure in the signal path from the leakage detection circuit to the battery.

  In addition, when the leakage detection processing unit determines that the leakage has not occurred in a state where the other electrode of the battery and the ground are connected by the switching unit, a failure occurs in the leakage detection circuit. It is preferable to further include a failure detection processing unit that determines that the error has occurred.

  According to this configuration, when the failure detection processing unit determines that no leakage has occurred by the leakage determination processing unit in a state in which the other electrode of the battery is connected to the ground by the switching unit, Since it is determined that a failure has occurred in the detection circuit, it is possible to automatically determine the failure of the leakage detection circuit.

  The switching unit preferably includes a switching element and an inspection resistor connected in series with the switching element.

  According to this configuration, when the switching element is turned on, the switching unit can electrically connect the other electrode of the battery to the ground via the inspection resistor.

  The inspection signal is an AC signal, and the signal path includes a voltage dividing resistor provided between the inspection signal supply unit and the one electrode, and the voltage dividing resistor and the one electrode. Preferably, the voltage detection unit detects a voltage of a connection path between the voltage dividing resistor and the capacitor as the detection voltage.

  According to this configuration, since the capacitor is interposed between the one electrode of the battery and the inspection signal supply unit, the inspection signal supply unit can be galvanically insulated from the battery. Therefore, even when the battery outputs a high voltage, the inspection signal supply unit can be protected from the battery voltage. If the inspection signal is an AC signal, the capacitor passes the inspection signal, so that it is possible to determine the failure of the leakage detection circuit while protecting the inspection signal supply unit from the battery voltage.

  Moreover, it is preferable that the said leak detection process part determines with the said leak having generate | occur | produced, when the said detection voltage is less than the preset determination value.

  According to this configuration, when leakage occurs, the signal path is connected to the ground via the leakage resistance. If it does so, the impedance of the said signal path | route will fall and the voltage of the signal path | route which transmits a test signal will fall. As a result, the detection voltage detected by the voltage detection unit decreases. Therefore, the leakage determination processing unit can determine that a leakage has occurred when the detected voltage decreases until it does not reach a preset determination value.

  The battery circuit board according to the present invention includes the above-described leakage detection circuit, a first terminal connectable to the one pole, a second terminal connectable to the other pole, the first and first terminals. A battery voltage detection unit that detects a voltage between two terminals as a voltage of the battery, the signal path is connected to the one pole via the first terminal, and the switching unit includes the second The leakage detection circuit, the first terminal, the second terminal, and the battery voltage detection unit are provided on the same substrate, connected to the other pole via a terminal.

  According to this configuration, when the battery voltage detection unit that detects the voltage of the battery and the leakage detection circuit are configured on the same substrate, the battery voltage detection unit and the leakage detection circuit share the first and second terminals. Is done. In this case, there is no need to separately provide a connection terminal for connecting the battery voltage detection unit to the battery and a connection terminal for connecting the leakage detection circuit to the battery. The number of connection terminals, the connection terminals, and the battery The number of wirings that connect can be reduced.

  Moreover, the battery power supply device according to the present invention includes the above-described leakage detection circuit and the battery. According to this configuration, in the battery power supply device including the battery and the leakage detection circuit, it is possible to improve the reliability of detecting a failure in the signal path from the leakage detection circuit to the battery.

  The leakage detection circuit, the battery circuit board, and the battery power supply device having such a configuration can improve the reliability of detecting a failure in the signal path from the leakage detection circuit to the battery.

It is a block diagram which shows an example of the battery power supply device provided with the leakage detection circuit which concerns on one Embodiment of this invention. It is a flowchart which shows an example of operation | movement of the leak detection circuit shown in FIG.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted. FIG. 1 is a block diagram illustrating an example of a battery power supply device including a leakage detection circuit according to an embodiment of the present invention.

  A battery power supply device 1 shown in FIG. 1 includes a battery circuit board 2, a battery B, and wirings L1 and L2. The battery B is, for example, an assembled battery configured by connecting a plurality of cells B1 in series. The cell B1 is a secondary battery cell such as a lithium ion secondary battery or a nickel hydride secondary battery. And the low potential side pole (total-pole) of the battery B is the negative electrode B (-) (one pole), and the high potential side pole (total + pole) of the battery B is the positive pole B (+) (the other side). ). The battery B outputs a voltage of, for example, about 400 V between the negative electrode B (−) and the positive electrode B (+). The negative electrode B (−) and the positive electrode B (+) are connected to a load device (not shown).

  Note that the plurality of cells B1 are not necessarily limited to an example of being connected in series. For example, a plurality of cells B1 may be connected in parallel, and the battery B may be configured by combining the cells B1 connected in parallel with the cells B1 connected in series. Moreover, the battery B may be comprised by the cell B1 single-piece | unit.

  The battery power supply device 1 is mounted on a vehicle such as a hybrid car or an electric vehicle. The vehicle body of the vehicle is a chassis ground G (ground).

  On the battery circuit board 2, a leakage detection circuit 3, a battery voltage detection unit 21, a connection terminal T1 (first terminal), a connection terminal T2 (second terminal), and a connection terminal T3 are provided.

  The leakage detection circuit 3 includes an inspection signal supply unit 31, a voltage detection unit 32, a switching unit 33, a control unit 34, a voltage dividing resistor R1, and a capacitor C. The switching unit 33 is configured by a series circuit of a switching element SW1 and a test resistor R2. The chassis ground G is used as a circuit ground for the leakage detection circuit 3 and the battery voltage detection unit 21.

  The connection terminal T1 is connected to the negative electrode B (−) through the wiring L1. The connection terminal T2 is connected to the positive electrode B (+) through the wiring L2. The connection terminal T3 is connected to an external device, for example, an unillustrated ECU (Electronic Control Unit). The connection terminals T1, T2, and T3 may be, for example, electrodes, connectors, terminal blocks, or wiring patterns such as lands and pads.

  The battery voltage detection unit 21 is configured using, for example, an analog-digital converter, a voltage dividing resistor, or the like. The battery voltage detector 21 detects the voltage between the connection terminals T1 and T2, that is, the battery voltage Vb of the battery B connected to the connection terminals T1 and T2, and converts the detected battery voltage Vb into a digital value. To the control unit 34.

  The inspection signal supply unit 31 is configured using, for example, an oscillation circuit. The inspection signal supply unit 31 outputs a sine wave AC signal having a peak value (amplitude) of 5 V as the inspection signal TS based on the chassis ground G in accordance with the control signal from the control unit 34. Note that the inspection signal TS is not necessarily a sine wave. The inspection signal TS may be a rectangular wave, for example.

  One end of the voltage dividing resistor R1 is connected to the inspection signal supply unit 31, and the other end of the voltage dividing resistor R1 is connected to one end of the capacitor C. The other end of the capacitor C is connected to the negative electrode B (−) through the connection terminal T1 and the wiring L1. Thus, the inspection signal TS output from the inspection signal supply unit 31 is guided to the connection terminal T1 through the signal path reaching the connection terminal T1 through the voltage dividing resistor R1 and the capacitor C, and further wired from the connection terminal T1. L1 leads to the negative electrode B (-).

  The capacitance of the capacitor C is set so that the impedance generated with respect to the frequency of the inspection signal TS can be negligibly small. Thereby, the capacitor C insulates the battery B from the inspection signal supply unit 31 and the voltage detection unit 32 while allowing the inspection signal TS to pass therethrough.

  The voltage detection unit 32 is configured by, for example, an analog / digital converter, a peak hold circuit, or the like. The voltage detector 32 detects the peak value of the voltage at the connection point P1 (one point on the connection path) between the voltage dividing resistor R1 and the capacitor C as the detection voltage Vd, and converts the detection voltage Vd into a digital value. Output to the control unit 34.

  Note that the voltage detector 32 is not necessarily limited to the example of detecting the peak value of the voltage at the connection point P1. For example, the voltage detector 32 may detect the amplitude value of the voltage at the connection point P1 as the detection voltage Vd, or may detect the effective value as the detection voltage Vd.

  The switching element SW1 may be a semiconductor switching element such as an FET (Field Effect Transistor) or a relay switch. One end of the switching element SW1 is connected to the positive electrode B (+) via the connection terminal T2 and the wiring L2. The other end of the switching element SW1 is connected to one end of the inspection resistor R2. The other end of the inspection resistor R2 is connected to the chassis ground G. The switching element SW1 and the inspection resistor R2 may be interchanged.

  The switching element SW1 is turned on (closed) and turned off (opened) in accordance with a control signal from the control unit 34. When the switching element SW1 is turned on, the positive electrode B (+) and the chassis ground G are brought into conduction through the inspection resistor R2. Further, when the switching element SW1 is turned off, the positive electrode B (+) is electrically disconnected from the chassis ground G.

  The control unit 34 includes, for example, a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), a serial communication circuit, and peripheral circuits thereof. And the control part 34 comprises the battery voltage monitoring part 341, the failure detection process part 342, and the electric leakage determination process part 343 by running the control program memorize | stored in ROM, for example.

  The battery voltage monitoring unit 341 receives information indicating the battery voltage Vb of the battery B from the battery voltage detection unit 21. Then, the battery voltage monitoring unit 341 transmits information indicating the battery voltage Vb to an external device such as an ECU connected to the connection terminal T3 by regular serial communication, for example. As a result, the battery voltage Vb of the battery B can be monitored in the external device. The control unit 34 may control charging / discharging of the battery B based on the battery voltage Vb detected by the battery voltage detection unit 21.

  The leakage detection processing unit 343 is configured such that the value of the detection voltage Vd detected by the voltage detection unit 32 is less than the preset determination value Vj during the period in which the inspection signal TS is output from the inspection signal supply unit 31. It is determined that a leak has occurred. The leakage in the battery power supply device 1 is a state where the insulation between the positive electrode B (+) or the negative electrode B (−) of the battery B and the chassis ground G is lowered, specifically, the positive electrode B (+ ) Or the negative electrode B (−) and the chassis ground G means a state in which the leakage resistance Rg having a resistance value that does not satisfy a predetermined reference resistance value as a resistance value necessary for ensuring insulation is connected. ing.

  The failure detection processing unit 342 turns on the switching element SW1 during a period in which the inspection signal TS is output from the inspection signal supply unit 31, thereby causing the positive electrode B (+) of the battery B to pass through the inspection resistor R2. Connected to chassis ground G.

  Then, the failure detection processing unit 342 determines that the leakage is generated by the leakage determination processing unit 343 during the period when the inspection signal TS is output from the inspection signal supply unit 31 and the switching element SW1 is on. If it is determined that the leakage detection circuit 3 is normal. On the other hand, the failure detection processing unit 342 determines that no leakage has occurred by the leakage determination processing unit 343 during the period when the inspection signal TS is output from the inspection signal supply unit 31 and the switching element SW1 is on. If it is determined that the leakage detection circuit 3 has failed.

  Next, the operation of the leakage detection circuit 3 configured as described above will be described. FIG. 2 is a flowchart showing an example of the operation of the leakage detection circuit 3 shown in FIG. First, the leakage determination processing unit 343 causes the inspection signal supply unit 31 to start outputting the inspection signal TS (step S1). Then, the inspection signal TS output from the inspection signal supply unit 31 is supplied to the negative electrode B (−) via the voltage dividing resistor R1, the capacitor C, the connection terminal T1, and the wiring L1.

  Next, the voltage detection unit 32 detects the peak value of the voltage at the connection point P1 as the detection voltage Vd, and a signal indicating the detection voltage Vd is transmitted to the leakage determination processing unit 343 (step S2).

  Next, the leakage detection processing unit 343 compares the detected voltage Vd with the determination value Vj (step S3). Here, if there is no leakage, the voltage at the connection point P1 is the voltage itself of the inspection signal TS output from the inspection signal supply unit 31. That is, if no leakage has occurred, the detection voltage Vd detected by the voltage detection unit 32 in step S2 is substantially equal to the peak value of the inspection signal TS output from the inspection signal supply unit 31, for example, 5V.

  On the other hand, when leakage occurs and, for example, the negative electrode B (−) and the chassis ground G are connected by the leakage resistance Rg as shown by the broken line in FIG. 1, the voltage at the connection point P1 is determined by the inspection signal TS. The voltage is divided by the resistance R1 and the leakage resistance Rg. That is, when a leakage occurs, the detection voltage Vd detected by the voltage detection unit 32 in step S <b> 2 is lower than the peak value of the inspection signal TS output by the inspection signal supply unit 31. Therefore, a voltage lower than the peak value of the inspection signal TS output by the inspection signal supply unit 31 is previously set as the determination value Vj so that it can be determined that the peak value of the inspection signal TS is lower than when there is no leakage. Is set.

  If the detection voltage Vd does not satisfy the determination value Vj (YES in step S3), it means that the inspection signal TS has decreased as a result of dividing the inspection signal TS by the voltage dividing resistor R1 and the leakage resistance Rg. Therefore, the leakage determination processing unit 343 determines that leakage has occurred (step S4). Then, the leakage determination processing unit 343 transmits information indicating that leakage has occurred to the external device via the connection terminal T3, for example, by serial communication (step S5), and ends the process.

  On the other hand, if the detected voltage Vd is equal to or higher than the determination value Vj (NO in step S3), it means that the leakage resistance Rg has not occurred and the voltage of the inspection signal TS has not decreased. Determines that no leakage has occurred (step S6).

  Next, the failure detection processing unit 342 turns on the switching element SW1 (step S7). Then, since the internal resistance of the battery B is so small as to be negligible, the negative electrode B (−) is the internal resistance of the battery B, the positive electrode B (+), the wiring L2, the connection terminal T2, the switching element SW1, and the test. It is connected to the chassis ground G through a resistor R2. In other words, the negative electrode B (−) of the battery B is in a pseudo electric leakage state in which the negative electrode B (−) of the battery B is connected to the chassis ground G via the inspection resistor R2 instead of the electric leakage resistor Rg.

  At this time, since the inspection signal TS is divided by the voltage dividing resistor R1 and the inspection resistor R2, the detection voltage Vd is lower than the determination value Vj as in the case where a leakage occurs.

  Next, the failure detection processing unit 342 causes the leakage detection processing unit 343 to execute a leakage detection process similar to that in step S3. That is, the leakage determination processing unit 343 compares the detection voltage Vd with the determination value Vj (step S9). At this time, as described above, since the detection voltage Vd should be lower than the determination value Vj, the leakage determination processing unit 343 detects that the detection voltage Vd is lower than the determination value Vj (YES in step S9). When it is determined that a fault has occurred (step S10), the failure detection processing unit 342 determines that the leakage detection circuit 3 is normal (step S11).

  Then, the failure detection processing unit 342 transmits information indicating that no leakage has occurred and information indicating that the leakage detection circuit 3 is normal to the external device via the connection terminal T3, for example, by serial communication. (Step S12), the process proceeds to Step S16.

  On the other hand, when the leakage detection processing unit 343 determines that the detection voltage Vd is equal to or higher than the determination value Vj (NO in step S9) and no leakage has occurred (step S13), the leakage is originally generated. When the determination is to be made, it is determined that no leakage has occurred. Therefore, the failure detection processing unit 342 determines that the leakage detection circuit 3 has failed (step S14).

  Here, the inspection signal supply unit 31 is connected to the negative electrode B (−) via the voltage dividing resistor R1 and the capacitor C, whereas the switching unit 33 is connected to the positive electrode B (+). The following effects can be obtained. That is, if the switching unit 33 is connected to the position of the arrow A in FIG. 1, even if the wiring path from the position of the arrow A to the negative electrode B (−), for example, the wiring L1 is disconnected. When the switching element SW1 of the switching unit 33 connected to the position of the arrow A is turned on, the voltage at the connection point P1 becomes a voltage obtained by dividing the inspection signal TS by the voltage dividing resistor R1 and the inspection resistor R2. . As a result, since the detection voltage Vd is lower than the determination value Vj, the leakage determination processing unit 343 determines in step S9 that the detection voltage Vd is lower than the determination value Vj (YES in step S9) and a leakage has occurred. The failure detection processing unit 342 determines that the leakage detection circuit 3 is normal (step S11).

  That is, if the switching unit 33 is connected to the position indicated by the arrow A in FIG. 1, the disconnection failure occurs in the wiring path from the position indicated by the arrow A to the negative electrode B (−). The failure detection processing unit 342 determines that the leakage detection circuit 3 is normal, and thus cannot detect a failure in the leakage detection circuit 3.

  On the other hand, according to the leakage detection circuit 3 shown in FIG. 1, since the switching unit 33 is connected to the positive electrode B (+), the wire breaks at any position in the wiring path from the connection point P1 to the negative electrode B (−). Even when this occurs, the switching unit 33 is disconnected from the inspection signal supply unit 31 due to disconnection. Therefore, even when the switching element SW1 is turned on (step S7), the voltage at the connection point P1 does not decrease. As a result, in step S9, the leakage detection processing unit 343 determines that the detection voltage Vd is equal to or higher than the determination value Vj (NO in step S9) and no leakage has occurred (step S13), and the failure detection processing unit 342 It is determined that the leakage detection circuit 3 has failed (step S14).

  In other words, according to the leakage detection circuit 3 shown in FIG. 1, no matter where the disconnection occurs in the wiring path from the connection point P1 to the negative electrode B (−) (for example, when the wiring L1 is disconnected). However, since the failure of the leakage detection circuit 3 can be detected, the reliability of detecting a failure in the signal path from the leakage detection circuit to the battery can be improved.

  Next, the leakage determination processing unit 343 transmits information indicating that the leakage detection circuit 3 is out of order to the external device via the connection terminal T3 by, for example, serial communication (step S15), and proceeds to step S16. To do.

  In step S16, the failure detection processing unit 342 stops the output of the inspection signal TS by the inspection signal supply unit 31 (step S16) and ends the process.

  In the battery circuit board 2 shown in FIG. 1, the connection terminals T <b> 1 and T <b> 2 and the wirings L <b> 1 and L <b> 2 are members used by the battery voltage detection unit 21 to detect the battery voltage of the battery B. In this way, the battery voltage detection unit 21 uses the connection terminals T1, T2 and the wirings L1, L2 in the battery voltage detection unit 21 and the fault detection process by the leakage detection circuit 3, thereby sharing the battery voltage detection unit. The connection terminals and wirings can be reduced as compared with the case where the connection terminals and wirings are separately provided for detection of the battery voltage Vb by 21 and for failure detection by the leakage detection circuit 3.

  In addition, in FIG. 2, although the example which performs the fault detection process after step S7 after performing the leak detection process of step S2-S6 was shown, it is not restricted to the example which performs a leak detection process before a failure detection process, Steps S2 to S6 may not be executed. Further, steps S12 and S15 need not be executed.

  In step S <b> 1, the failure detection processing unit 342 may cause the inspection signal supply unit 31 to start outputting the inspection signal TS. Further, the inspection signal supply unit 31 may always output the inspection signal TS without executing steps S1 and S2.

  Moreover, although the negative electrode B (-) (one pole) and the connection terminal T1 were connected and the positive electrode B (+) (the other pole) and the connection terminal T2 were connected, the positive electrode B (+ ) (One pole) and the connection terminal T1 may be connected, and the negative electrode B (−) (the other pole) and the connection terminal T2 may be connected.

  Moreover, although the battery power supply device 1 is mounted on a vehicle and the vehicle body is shown as a chassis ground G (ground), the battery power supply device 1 may be mounted on a device other than the vehicle. The housing may be grounded (frame ground). Moreover, it is not restricted to the example which uses a chassis (housing | casing) as a ground, You may use earth | ground (grounding) as a ground.

  In addition, the leakage detection circuit 3 is not necessarily limited to the example configured as the battery circuit board 2 on the same substrate as the voltage detection unit 32.

  In addition, an example in which the inspection signal TS is an AC signal and the inspection signal supply unit 31 supplies the inspection signal TS to one electrode of the battery B via the voltage dividing resistor R1 and the capacitor C is shown. It is not limited to AC signals. The inspection signal supply unit 31 may supply the inspection signal TS to one electrode of the battery B, and the leakage detection circuit 3 may not include the voltage dividing resistor R1 or the capacitor C.

  Further, the switching element SW1 may be a changeover switch that can be operated by the user, and the failure detection processing unit 342 may not be provided. In this case, after the user turns on the switching element SW1, by executing steps S1 to S6 by the leakage determination processing unit 343, if the leakage determination processing unit 343 determines that leakage has occurred (if the occurrence of leakage is notified) ) The user can determine that the leakage detection circuit 3 is normal, and if the leakage detection processing unit 343 does not determine that the leakage has occurred (if the leakage occurrence is not notified), the leakage detection circuit 3 has failed. Can be determined by the user.

  INDUSTRIAL APPLICABILITY The present invention can be suitably used as a leakage detection circuit for detecting leakage, a circuit board for a battery including a leakage detection circuit, and a battery power supply device in various equipment and facilities that use a battery as a power source.

DESCRIPTION OF SYMBOLS 1 Battery power supply device 2 Battery circuit board 3 Leakage detection circuit 21 Battery voltage detection part 31 Inspection signal supply part 32 Voltage detection part 33 Switching part 34 Control part 341 Battery voltage monitoring part 342 Failure detection process part 343 Leakage determination process part B Battery B (+) Positive electrode B (-) Negative electrode B1 Cell C Capacitor G Chassis ground L1, L2 Wiring P1 Connection point R1 Voltage dividing resistor R2 Inspection resistance Rg Leakage resistance SW1 Switching element T1, T2, T3 Connection terminal TS Inspection signal Vb Battery Voltage Vd Detection voltage Vj Judgment value

Claims (7)

A leakage detection circuit for detecting a leakage between a ground and a battery insulated from the ground,
An inspection signal supply unit for supplying a predetermined inspection signal to one of the electrodes of the battery;
A signal path for guiding the inspection signal supplied from the inspection signal supply unit to one pole of the battery;
A voltage detector that detects the voltage of the signal path as a detection voltage;
A leakage determination processing unit that determines whether or not the leakage occurs based on the detection voltage;
A leakage detecting circuit comprising: a switching unit that switches presence / absence of conduction between the other electrode of the battery and the ground. In a state where the other part of the battery is electrically connected to the ground by the switching unit, if the leakage determination processing unit determines that the leakage has not occurred, a failure occurs in the leakage detection circuit. The leakage detection circuit according to claim 1, further comprising a failure detection processing unit that determines that the fault has occurred. The switching unit is
A switching element;
The leakage detection circuit according to claim 1, further comprising an inspection resistor connected in series with the switching element. The inspection signal is an AC signal,
The signal path is
A voltage dividing resistor provided between the inspection signal supply unit and the one pole;
A capacitor interposed between the voltage dividing resistor and the one pole,
The voltage detector is
The leakage detection circuit according to claim 1, wherein a voltage on a connection path between the voltage dividing resistor and the capacitor is detected as the detection voltage. The leakage determination processing unit
The leakage detection circuit according to claim 1, wherein when the detected voltage is less than a preset determination value, it is determined that the leakage has occurred. The leakage detection circuit according to any one of claims 1 to 5,
A first terminal connectable to the one pole;
A second terminal connectable to the other pole;
A battery voltage detector that detects a voltage between the first and second terminals as a voltage of the battery;
The signal path is
Connected to the one pole via the first terminal;
The switching unit is
Connected to the other pole via the second terminal;
The battery leakage detection circuit, the first terminal, the second terminal, and the battery voltage detection unit are provided on the same substrate. The leakage detection circuit according to any one of claims 1 to 5,
A battery power supply device including the battery.

Images