JP2018069803A - Auxiliary power unit for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an auxiliary power unit for vehicle that comprises a power storage device which is grounded and connected to a main power supply of a vehicle, and that can supply electric power continuously to an electrical accessory upon demand even if wiring connecting the power storage device and the electrical accessory to each other short-circuits.SOLUTION: An auxiliary power unit 10 for vehicle comprises: a power storage device 21 which is grounded and connected to a main power supply 3 of a vehicle; wiring lines 4c, 4d which connect nodes 21a, 21b provided at both end parts of the power storage device 21 and an electric load 5 of an electrical accessory to each other; and a current limiting part 22 which is connected in series between a ground point Gr of the power storage device 21 and a ground point-side node of the power storage device 21.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an auxiliary power supply device for a vehicle including a power storage device that is grounded and connected to a main power supply of the vehicle.

  In recent years, in order to ensure safety during traveling of a vehicle, a vehicle including an automatic door lock mechanism that automatically locks a door when the vehicle exceeds a predetermined speed has been put into practical use. The automatic door lock mechanism may be configured to automatically release the door lock upon detecting an impact, for example, so that an occupant can easily get out of the vehicle when the vehicle encounters an accident.

  At this time, if a short circuit (short circuit, ground fault) occurs in the wiring that electrically connects the main power supply such as a battery and the automatic door lock mechanism in the event of an accident, power can be supplied from the main power supply to the automatic door lock mechanism. For example, it may be possible to separately provide a spare wiring for connecting the main power source and the automatic door lock mechanism, but this is not preferable because the wiring route becomes complicated.

  Here, Patent Document 1 includes switching means for switching the main power source and the power storage device to connect the power storage device and the electrical component when a short circuit occurs in the wiring connecting the main power source and the electrical component. A power storage device is described.

Japanese Patent Laid-Open No. 9-46928

  By using the auxiliary power supply described in Patent Document 1, even if a short circuit occurs in the wiring connecting the power storage device and the main power supply, power is continuously supplied to electrical components such as an automatic door lock mechanism as required. it can. On the other hand, Patent Document 1 does not discuss at all about the drivability of an electrical component when a short circuit occurs in the wiring connecting the power storage device and the electrical component.

  The present invention has been made to solve the above-described problems, and is an auxiliary power supply device for a vehicle including a power storage device that is grounded and connected to a main power supply of the vehicle, the power storage device and an electrical component. It is an object of the present invention to provide a vehicular auxiliary power supply device that can continue to supply electric power to an electrical component as required even when a short circuit occurs in any of the wirings connecting the two.

  In order to solve the above-described problems, the auxiliary power supply for a vehicle according to the present invention is configured as follows.

The invention according to claim 1 is an auxiliary power supply device for a vehicle,
A power storage device that is grounded and connected to a main power source of the vehicle;
Wiring for connecting nodes provided at both ends of the power storage device and electrical loads of electrical components;
A current limiting unit connected in series between a ground point of the power storage device and a ground point side node of the power storage device;

The invention according to claim 2 is the auxiliary power supply device for a vehicle according to claim 1,
The current limiting unit includes a rectifying element.

The invention according to claim 3 is the auxiliary power supply device for a vehicle according to claim 1,
The current limiting unit has an electrical resistance.

Invention of Claim 4 is the auxiliary power supply device for vehicles of Claim 1, Comprising:
A voltage detection unit connected in parallel to the power storage device or a current detection unit connected in series to the power storage device;
The current limiting unit includes a switch that is opened in response to a decrease in terminal voltage of the power storage device detected by the voltage detection unit or a decrease in current flowing through the power storage device detected by the current detection unit.

The invention according to claim 5 is the auxiliary power supply device for a vehicle according to any one of claims 1 to 4,
The electrical component is a door lock actuator of a vehicle.

  According to the first aspect of the present invention, the current limiting unit is connected in series between the ground point of the power storage device and the ground point side node of the power storage device, and the ground point and the power storage device are connected via the ground point side node. Current flowing in one or both directions is limited, so even if a short circuit occurs in any of the wires connecting the nodes provided at both ends of the power storage device and the electrical load of the electrical component, The power can continue to be supplied to the electrical load of the product.

  According to the second aspect of the present invention, the rectifying element is connected in series between the ground point of the power storage device and the ground point side node of the power storage device, and the ground point and the power storage device are connected via the ground point side node. The current flowing in one direction is cut off, so even if one of the wirings connecting the nodes provided at both ends of the power storage device and the electrical load of the electrical component is short-circuited, It is possible to continue supplying power to the load.

  According to the invention of claim 3, the electrical resistance is connected in series between the ground point of the power storage device and the ground point side node of the power storage device, and the ground point and the power storage device are connected via the ground point side node. Therefore, even if a short circuit occurs in any of the wirings connecting the nodes provided at both ends of the power storage device and the electrical load of the electrical component, the electrical load of the electrical component is reduced. Can continue to supply power.

  According to the fourth aspect of the present invention, when a short circuit occurs in any of the wirings connecting the nodes provided at both ends of the power storage device and the electrical load of the electrical component, the voltage detection unit causes the terminals of the power storage device to be connected. A decrease in voltage is detected, or a decrease in current flowing through the power storage device is detected by the current detection unit. A switch connected in series between the ground point of the power storage device and the ground point side node of the power storage device is opened in response to these detections, and the ground point and the power storage device are connected via the ground point side node. The current flowing in both directions is cut off, so even if one of the wires connecting the nodes provided at both ends of the power storage device and the electrical load of the electrical component is short-circuited, the electrical load of the electrical component is It can continue to supply power.

  According to the invention described in claim 5, since the electrical component is a door lock actuator, the effects of claims 1 to 4 are specifically achieved.

It is a top view which shows the vehicle provided with the electrical storage apparatus which concerns on one embodiment of this invention. 1 is an equivalent circuit diagram illustrating a schematic configuration of a power storage device according to a first embodiment of the present invention. It is an equivalent circuit diagram which shows schematic structure of the electrical storage apparatus by a comparative example. It is an equivalent circuit schematic which shows schematic structure of the electrical storage apparatus which concerns on 2nd Embodiment of this invention. It is an equivalent circuit schematic which shows schematic structure of the electrical storage apparatus which concerns on 3rd Embodiment of this invention. It is an equivalent circuit diagram which shows schematic structure of the electrical storage apparatus which concerns on the modification of 3rd Embodiment of this invention. It is an equivalent circuit diagram which shows schematic structure of the electrical storage apparatus which concerns on the modification of 1st Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.

  As shown in FIG. 1, the vehicle 1 includes a main battery 3 that is a main power source of the vehicle provided in the engine room 2. The main battery 3 is electrically connected to an electric load 5 (hereinafter referred to as an actuator) of a door lock actuator provided on the door body via a wiring 4. The wiring 4 constitutes a power supply line from the main battery 3 to the actuator 5. In the embodiment, the vehicle 1 is provided with four doors, and an actuator 5 (5a to 5d) is provided on each door body.

  The actuator 5 is a link mechanism provided in the door latch mechanism between a state where the operating force of the door opening lever is transmitted (unlocked state) and a state where it is not transmitted (locked state) using a DC motor (not shown). Operates to switch states alternatively.

  The main battery 3 is electrically connected to the actuator 5 via a vehicle auxiliary power supply 10 (hereinafter simply referred to as an auxiliary power supply). In the auxiliary power supply 10, for example, when the vehicle 1 encounters an accident, the main battery 3 fails or the wiring 4 is short-circuited. As a result, the power supply line from the main battery 3 to the actuator 5 is cut off. When this occurs, the actuator 5 is driven instead of the main battery 3.

  The auxiliary power supply 10 includes an auxiliary battery 20 and a door lock unit 30. The auxiliary battery 20 and the door lock unit 30 are grounded. The auxiliary battery 20 may be disposed at a location where deformation is relatively small (for example, below the seat) even when a collision load is applied to the vehicle body due to an accident or the like. The door lock unit 30 may be disposed inside the instrument panel. In FIG. 1, the auxiliary battery 20 and the door lock unit 30 are drawn larger than actual dimensions.

[First Embodiment]
As shown in FIG. 2, the auxiliary power supply device 10 includes a power storage device 21 that is electrically connected to the main battery 3. The power storage device 21 is provided in the auxiliary battery 20 (see FIG. 1). The power storage device 21 may be, for example, an electric double layer capacitor, a lithium ion capacitor, a nickel metal hydride battery, or a lead storage battery.

  The auxiliary power supply 10 has first, second, third, fourth and fifth terminals 11, 12, 13, 14, 15. The first terminal 11 and the second terminal 12 are electrically connected to the positive electrode and the negative electrode of the power storage device 21 via the high potential side node 21a and the low potential side node 21b provided at both ends of the power storage device 21, respectively. It is connected to the.

  The wiring 4 that electrically connects the main battery 3 and the actuator 5 includes first, second, third, and fourth wiring portions 4a, 4b, 4c, and 4d. The first wiring part 4 a electrically connects the positive electrode of the main battery 3 and the first terminal 11 via the fuse 6. The second wiring portion 4 b electrically connects the negative electrode of the main battery 3 and the second terminal 12. The third wiring portion 4 c electrically connects the actuator 5 and the third terminal 13. The fourth wiring portion 4 d electrically connects the actuator 5 and the fourth terminal 14.

  The power storage device 21 is grounded to the metal part of the vehicle body via the rectifying element 22. Specifically, rectifying element 22 is connected in series between low potential side node 21b of power storage device 21 and ground point Gr of power storage device 21 to the vehicle body. Therefore, in the first embodiment, the low potential side node 21b may be referred to as a ground point side node, and the high potential side node 21a may be referred to as an anti-ground point side node. In addition, as shown in FIG. 2, the negative electrode (cathode) of the main battery 3 is also grounded to the vehicle body. The rectifying element 22 is a current limiting unit that blocks current flowing in one direction between the low potential side node 21b and the ground point Gr when the potential of the low potential side node 21b of the power storage device 21 is lower than the ground potential. Function. The rectifying element 22 may be a diode.

  An attenuator 23 having a function of preventing a high voltage exceeding the withstand voltage of the power storage device 21 from being supplied from the main battery 3 to the power storage device 21 is connected in series between the main battery 3 and the power storage device 21. Yes. In FIG. 2, the attenuator 23 is provided between the positive electrode of the main battery 3 and the positive electrode of the power storage device 21, but is provided between the negative electrode of the main battery 3 and the negative electrode of the power storage device 21. Also good. The attenuator 23 may be a Zener diode.

  A control circuit 31 is provided between the power storage device 21 and the actuator 5. The control circuit 31 is electrically connected to an external device (not shown) via the fifth terminal 15 of the auxiliary power supply device 10, and is configured to drive the actuator 5 in response to a request signal from the external device. Yes. In one example, the external device is an airbag control device that includes a collision detection device that detects that a collision load has been applied to the vehicle body.

  The control circuit 31 includes switching units 31a and 31b configured by relays, for example. By switching the connection using the switching units 31a and 31b, the actuator 5 is driven so that the door lock mechanism shifts from the unlocked state to the locked state, or the actuator 5 shifts from the locked state to the unlocked state. Can be switched.

(Comparative example)
Next, in order to explain the effect of the auxiliary power supply device 10 according to the embodiment, an auxiliary power supply device 110 according to a comparative example will be described. In the description of the auxiliary power supply device 110 according to the comparative example, the same components as those included in the auxiliary power supply device 10 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 3, in the auxiliary power supply device 110 according to the comparative example, the rectifying element 22 described above is not between the ground point Gr and the low potential side node 21 b of the power storage device 21, but the positive electrode of the main battery 3 and the power storage device. 21 between the high-potential-side node 21a.

Next, an operation obtained by the auxiliary power supply device 110 according to the comparative example will be described.
For example, when the vehicle 1 encounters an accident and a collision load is input to the vehicle 1 from the front, the high potential side first connecting the main battery 3 and the power storage device 21 (for example, located below the seat) is electrically connected. There is a possibility that a short circuit or disconnection may occur in the first wiring part 4a and the second wiring part 4b on the low potential side, or the main battery 3 may fail. In this state, it is assumed that the control circuit 31 receives a request signal for driving the actuator 5 from an external device.

  First, consider a case where a short circuit occurs in the second wiring portion 4b. The second wiring portion 4b is electrically connected to the ground point Gr before the short circuit occurs. Therefore, even after a short circuit occurs, power is supplied from the main battery 3 to the actuator 5 and the actuator 5 is driven.

  On the other hand, when a short circuit occurs in the first wiring part 4a, the positive and negative electrodes of the main battery 3 are short-circuited via the first wiring part 4a, the ground point Gr and the second wiring part 4b, so that the fuse 6 is blown. Then, the power supply line from the main battery 3 to the actuator 5 is cut off. At this time, the anode-side potential of the rectifying element 22 is the ground potential, the cathode-side potential is the positive potential of the power storage device 21, and the rectifying element 22 is in a reverse bias state, so the gap between the positive electrode and the negative electrode of the power storage device 21 is There is no short circuit.

  As a result, even when the power supply line is cut off, the positive electrode of the power storage device 21 charged by the main battery 3 is connected to the actuator 5 via the third wiring portion 4c, and further from the actuator 5 to the fourth wiring. A current flows to the negative electrode of the power storage device 21 through the portion 4d. In this way, electric power is supplied from the power storage device 21 to the actuator 5 and the actuator 5 is driven.

  The power supply line is also disconnected when the first wiring portion 4a or the second wiring portion 4b is disconnected. Even if the main battery 3 fails, the power supply line is cut off. Under these circumstances, no current flows from the positive electrode of the power storage device 21 to the negative electrode of the power storage device 21 via the first wiring portion 4a, the ground point Gr, and the second wiring portion 4b. Therefore, as in the case where a short circuit occurs in the first wiring portion 4a, power is supplied from the power storage device 21 to the actuator 5, and the actuator 5 is driven.

  Next, when a collision load is input to the vehicle 1 from the side, the high potential side first connecting the control circuit 31 (for example, located inside the instrument panel) and the actuator 5 located on the door body is connected. One of the 3 wiring part 4c and the fourth wiring part 4d on the low potential side may come into contact with the metal part of the vehicle body and cause a short circuit.

  First, consider a case where a short circuit has occurred in the fourth wiring portion 4d along the path indicated by the symbol B in FIG. The fourth wiring portion 4d is electrically connected to the ground point Gr before the short circuit occurs. Therefore, even after a short circuit occurs, power is supplied from the main battery 3 to the actuator 5 and the actuator 5 is driven.

  On the other hand, when a short circuit occurs in the third wiring portion 4c along the path indicated by the symbol A in FIG. 3 and the third wiring portion 4c reaches the ground potential, the first wiring portion 4a and the first wiring portion 4a are connected between the positive electrode and the negative electrode of the main battery 3. Since the short circuit occurs through the 3 wiring portion 4c, the ground point Gr, and the second wiring portion 4b (unless the electrical resistance of the attenuator 23 is large), the fuse 6 is blown, and the power supply line from the main battery 3 to the actuator 5 is disconnected. I will be refused. In addition, since the positive electrode and the negative electrode of power storage device 21 are short-circuited via third wiring portion 4c, ground point Gr, and second wiring portion 4c, power is not supplied from power storage device 21 to actuator 5. As described above, in the comparative example, the actuator 5 is not driven when a short circuit occurs in the third wiring portion 4c on the high potential side.

(Operation obtained by the auxiliary power supply 10)
Next, the operation obtained by the auxiliary power supply device 10 according to the first embodiment will be described.
First, when a short circuit occurs in the first wiring part 4a and the first wiring part 4a reaches the ground potential, the first wiring part 4a, the ground point Gr, and the second wiring part 4b are connected between the positive electrode and the negative electrode of the main battery 3. Therefore, the fuse 6 is blown and the power supply line from the main battery 3 to the actuator 5 is cut. At this time, the anode side potential of the rectifying element 22 is a potential obtained by subtracting the terminal voltage of the power storage device 21 from the ground potential, the cathode side potential is the ground potential, and the rectifying element 22 is in a reverse bias state. There is no short circuit between the electrode and the negative electrode. Thus, electric power is supplied from the power storage device 21 to the actuator 5 through the same current path as in the comparative example, and the actuator 5 is driven.

  Next, when a short circuit occurs in the second wiring part 4b, when the first wiring part 4a or the second wiring part 4b is disconnected, when the main battery 3 fails, and in the path indicated by reference numeral B in FIG. The current path when a short circuit occurs in the fourth wiring portion 4d is as described in the comparative example. Electric power is supplied from the main battery 3 or the power storage device 21 to the actuator 5, and the actuator 5 is driven.

  Next, when a short circuit occurs in the third wiring portion 4c along the path indicated by the symbol A in FIG. 2 and the third wiring portion 4c reaches the ground potential, the first wiring portion 4a is connected between the positive electrode and the negative electrode of the main battery 3. Since the short circuit occurs through the third wiring portion 4c, the ground point Gr, and the second wiring portion 4b, the fuse 6 is melted and the power supply line from the main battery 3 to the actuator 5 is cut off. At this time, the anode side potential of the rectifying element 22 is a potential obtained by subtracting the terminal voltage of the power storage device 21 from the ground potential, the cathode side potential is the ground potential, and the rectifying element 22 is in a reverse bias state. There is no short circuit between the electrode and the negative electrode.

  As a result, even when the power supply line is cut off, the positive electrode of the power storage device 21 charged by the main battery 3 is connected to the actuator 5 via the third wiring portion 4c, and further from the actuator 5 to the fourth wiring. A current flows to the negative electrode of the power storage device 21 through the portion 4d. In this way, electric power is supplied from the power storage device 21 to the actuator 5 and the actuator 5 is driven.

  As described above, according to the auxiliary power supply device 10 according to the first embodiment, not only when the first wiring part 4a and the second wiring part 4b are short-circuited or disconnected, or when the main battery 3 has failed, Even when a short circuit occurs in either the third wiring portion 4c or the fourth wiring portion 4d, electric power is continuously supplied to the actuator 5 and the actuator 5 is driven.

[Second Embodiment]
In the description of the auxiliary power supply device 210 according to the second embodiment, the same components as those included in the auxiliary power supply device 10 according to the first embodiment and the auxiliary power supply device 110 according to the comparative example are denoted by the same reference numerals and are described in detail. Is omitted.

  In the auxiliary power supply device 210 according to the second embodiment, instead of the rectifying element 22 illustrated in FIG. 2, the resistor 24 includes a ground point Gr to the vehicle body of the power storage device 21 and a low potential side node 21 b of the power storage device 21. They are connected in series. In one example, the resistor 24 has an electrical resistance that is at least greater than the electrical load of the actuator 5. In another example, the resistor 24 has the same electrical resistance as the electrical load of the actuator 5. In another example, the resistor 24 has a lower electrical resistance than at least the electrical load of the actuator 5. The resistor 24 functions as a current limiting unit that reduces the current flowing in both directions between the low potential side node 21b and the ground point Gr.

Next, the operation obtained by the auxiliary power supply device 210 according to the second embodiment will be described.
First, when a short circuit occurs in the first wiring part 4a and the first wiring part 4a reaches the ground potential, the positive electrode and the negative electrode of the main battery 3 are short-circuited. The power supply line to is cut off. At this time, since the positive electrode and the negative electrode of the power storage device 21 are electrically connected via the resistor 24, a current corresponding to the electric resistance of the resistor 24 flows without causing a short circuit. Thus, electric power is supplied from the power storage device 21 to the actuator 5 through the same current path as in the comparative example, and the actuator 5 is driven. Note that, in an example in which the electrical resistance of the resistor 24 is greater than at least the electrical load of the actuator 5, the current flowing through the resistor 24 can be reduced to suppress the energy consumption of the power storage device 21 by the resistor 24.

  Next, when a short circuit occurs in the second wiring portion 4b, when the first wiring portion 4a or the second wiring portion 4b is disconnected, when the main battery 3 fails, and in the path indicated by reference numeral B in FIG. The current path when a short circuit occurs in the fourth wiring portion 4d is as described in the comparative example. Electric power is supplied from the main battery 3 or the power storage device 21 to the actuator 5, and the actuator 5 is driven.

  Next, when a short circuit occurs in the third wiring portion 4c along the path indicated by A in FIG. 4 and the third wiring portion 4c reaches the ground potential, the first wiring portion 4a is connected between the positive electrode and the negative electrode of the main battery 3. Since the short circuit occurs through the third wiring portion 4c, the ground point Gr, and the second wiring portion 4b, the fuse 6 is melted and the power supply line from the main battery 3 to the actuator 5 is cut off. At this time, since the positive electrode and the negative electrode of the power storage device 21 are electrically connected via the resistor 24, there is no short circuit, and a current corresponding to the value of the electric resistance of the resistor 24 is generated. Flowing. Thus, electric power is supplied from the power storage device 21 to the actuator 5 through the same current path as in the comparative example, and the actuator 5 is driven. Note that, in an example in which the electrical resistance of the resistor 24 is greater than at least the electrical load of the actuator 5, the current flowing through the resistor 24 can be reduced to suppress the energy consumption of the power storage device 21 by the resistor 24.

  As described above, according to the auxiliary power supply device 210 according to the second embodiment, not only when the first wiring portion 4a and the second wiring portion 4b are short-circuited or disconnected, or when the main battery 3 has failed, Even when a short circuit occurs in either the third wiring portion 4c or the fourth wiring portion 4d, electric power is continuously supplied to the actuator 5 and the actuator 5 is driven. In particular, in the second embodiment, the resistor 24 functions to prevent a high voltage exceeding the withstand voltage of the power storage device 21 from being supplied from the main battery 3 to the power storage device 21, so that the attenuator 23 can be omitted. .

[Third Embodiment]
In the description of the auxiliary power supply 310 according to the third embodiment, the same components as those included in the auxiliary power supply 10 according to the first embodiment, the auxiliary power supply 110 according to the comparative example, and the auxiliary power supply 210 according to the second embodiment. Are denoted by the same reference numerals, and detailed description thereof is omitted.

  In the auxiliary power device 210 according to the third embodiment, instead of the rectifying element 22 shown in FIG. 2, the switch 25 is connected between the ground point Gr to the vehicle body of the power storage device 21 and the low potential side node 21 b of the power storage device 21. Connected in series. The switch 25 is normally closed. The switch 25 may be, for example, a relay or a transistor (for example, MOSFET: metal oxide semiconductor field effect transistor).

  The switch 25 is electrically connected to a voltage detection unit 26 that is connected in parallel to the power storage device 21 and detects a terminal voltage of the power storage device 21. The voltage detection unit 26 includes, for example, a control unit configured by a microcomputer and a storage unit (both not shown). The maximum value of the terminal voltage of the power storage device 21 is recorded in the storage unit of the voltage detection unit 26. The control unit of the voltage detection unit 26 is configured to supply an electrical signal for opening the switch 25 to the switch 25 when the voltage at the terminal 11 of the power storage device 21 falls below a predetermined threshold value that is smaller than the maximum value. .

  The switch 25 functions as a current limiting unit that blocks current flowing in both directions between the low potential side node 21b and the ground point Gr when the terminal voltage of the power storage device 21 is reduced from the maximum value.

Next, the operation obtained by the auxiliary power supply device 310 according to the third embodiment will be described.
First, when the first wiring part 4a is short-circuited and the first wiring part 4a reaches the ground potential, the space between the positive electrode and the negative electrode of the main battery 3 passes through the first wiring part 4a, the ground point Gr, and the second wiring part 4b. Therefore, the fuse 6 is melted and the power supply line from the main battery 3 to the actuator 5 is cut off. At this time, the voltage at the terminal 11 of the power storage device 21 decreases at the moment when a current (ground fault current) starts flowing between the positive electrode and the negative electrode of the power storage device 21 in response to a request signal from the external device. An electric signal is supplied from the detection unit 26 to open the switch 25, and the switch 25 is opened. Therefore, there is no short circuit between the positive electrode and the negative electrode of the power storage device 21. Thus, electric power is supplied from the power storage device 21 to the actuator 5 through the same current path as in the comparative example, and the actuator 5 is driven.

  Next, when a short circuit occurs in the second wiring part 4b, the first wiring part 4a or the second wiring part 4b is disconnected, the main battery 3 fails, and the short circuit occurs in the fourth wiring part 4d. The current path in this case is as described in the comparative example, and power is supplied from the main battery 3 or the power storage device 21 to the actuator 5 to drive the actuator 5.

  Next, when a short circuit occurs in the third wiring portion 4c and the third wiring portion 4c reaches the ground potential, the first wiring portion 4a, the third wiring portion 4c, and the ground point Gr are connected between the positive electrode and the negative electrode of the main battery 3. Since the short circuit occurs via the second wiring portion 4b, the fuse 6 is melted and the power supply line from the main battery 3 to the actuator 5 is disconnected. At this time, when a request signal from an external device is received and a current (ground fault current) starts to flow between the positive electrode and the negative electrode of the power storage device 21, the terminal voltage of the power storage device 21 decreases, and the voltage detection unit 26, an electrical signal is supplied to open the switch 25, and the switch 25 is opened. Therefore, there is no short circuit between the positive electrode and the negative electrode of the power storage device 21. Thus, electric power is supplied from the power storage device 21 to the actuator 5 through the same current path as in the comparative example, and the actuator 5 is driven.

  As described above, according to the auxiliary power supply device 310 according to the third embodiment, not only when the first wiring part 4a and the second wiring part 4b are short-circuited or disconnected, or when the main battery 3 has failed, Even when a short circuit occurs in either the third wiring portion 4c or the fourth wiring portion 4d, electric power is continuously supplied to the actuator 5 and the actuator 5 is driven.

  In the third embodiment, instead of the voltage detection unit 26 connected in parallel to the power storage device 21, a current detection unit 27 connected in series to the power storage device 21 may be provided as shown in FIG. The current detection unit 27 includes, for example, a control unit configured by a microcomputer and a storage unit (both not shown), and the control unit of the current detection unit 27 detects a current in a direction in which the power storage device 21 is discharged. In this case, an electrical signal for opening the switch 25 is supplied to the switch 25. According to this example, the same operation as when the voltage detection unit 26 is provided can be obtained.

[Modification]
Although the present invention has been described with the embodiment, the present invention is not limited to the above-described embodiment. The features described in each embodiment may be freely combined. In addition, various improvements, design changes, and deletions may be added to the above-described embodiment.

  For example, in the above-described embodiment, the example in which the negative electrode of the main battery 3 and the negative electrode side of the power storage device 21 are electrically connected to the ground point Gr has been described. The present invention is not limited to this, and as shown in FIG. 7, even if the positive electrode of the main battery 3 and the positive electrode side of the power storage device 21 are electrically connected to the ground point Gr, the same effect is obtained. Will be understood by those skilled in the art. At this time, when the rectifying element 22 is provided as a current limiting unit that limits the current flowing between the ground point Gr and the high potential side node 21a (in this example, the ground point side node) of the power storage device 21, Is provided on the grounding point Gr side and the cathode is provided on the high potential node 21a side.

  In the above-described embodiment, the rectifying element 22, the resistor 24, or the switch 25 is provided as a current limiting unit that limits or blocks the current flowing between the low potential side node 21b and the ground point Gr. However, the present invention is not limited to this. For example, when a fuse is provided, the same effect can be obtained.

  In the above-described embodiment, the door lock actuator 5 is described as an electrical component that needs to be driven using the power storage device 21 instead of the main battery 3 when the power supply line from the main battery 3 is cut off. The present invention is not limited to this, and the electrical component may be, for example, a motor for a power window, a parking brake or a brake assist, an emergency call system, an automatic hazard flashing system, or the like.

  As described above, according to the present invention, in a vehicle auxiliary power supply device including a power storage device connected to a main power supply of a vehicle, for example, when a vehicle encounters an accident, a collision load is applied from the front or side, Even when a short circuit occurs in the wiring connecting the device and the electrical component, power can be continuously supplied to the electrical component as required. Therefore, the present invention may be suitably used in the field of manufacturing vehicles equipped with electrical components such as a motor for a power window, a parking brake or a brake assist, an emergency call system, and an automatic hazard flashing system.

DESCRIPTION OF SYMBOLS 1 Vehicle 3 Main battery 4 Wiring 4a, 4b, 4c, 4d 1st, 2nd, 3rd, 4th wiring part 5 (5a-5d) Door lock actuator 6 Fuse 10, 210, 310 Auxiliary power supply device 20 for vehicles Auxiliary Battery 21 Power storage device 21a High potential side node 21b Low potential side node 22 Rectifier 23 Attenuator 24 Resistor 25 Switch 26 Voltage detector 30 Door lock unit 31 Control circuit

Claims (5)

A power storage device that is grounded and connected to a main power source of the vehicle;
Wiring for connecting nodes provided at both ends of the power storage device and electrical loads of electrical components;
A current limiting unit connected in series between a ground point of the power storage device and a ground point side node of the power storage device;
Auxiliary power supply device for vehicles. The current limiting unit includes a rectifying element,
The auxiliary power supply for a vehicle according to claim 1. The current limiting unit has an electrical resistance.
The auxiliary power supply for a vehicle according to claim 1. A voltage detection unit connected in parallel to the power storage device or a current detection unit connected in series to the power storage device;
The current limiting unit includes a switch that is opened in response to a decrease in terminal voltage of the power storage device detected by the voltage detection unit or a decrease in current flowing in the power storage device detected by the current detection unit,
The auxiliary power supply for a vehicle according to claim 1. The electrical component is a vehicle door lock actuator.
The auxiliary power supply for vehicles according to any one of claims 1 to 4.

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