JP2020124039A - Auxiliary power supply device for vehicle and power supply method - Google Patents

Abstract

To provide an auxiliary power supply device for a vehicle capable of driving electrical equipment when a main power supply is interrupted, by a power storage device with a small capacity.SOLUTION: By dividing DC voltage into two and supplying the DC voltage with temporal difference to four door lock motors 16FL, 16RL, 16FR, and 16RR, driving current from a power storage device 20 is decreased, influence of internal resistance of the power storage device is reduced, so that a reduction of terminal voltage of the power storage device while current is flowing to electric load is suppressed.SELECTED DRAWING: Figure 1

Description

The present invention relates to a vehicle auxiliary power supply device that supplies electric power from a power storage device to a predetermined electric component when power supply from a main power supply is cut off, and a power supply method.

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

At this time, in the event of an accident, if the wiring that connects the main power supply such as a battery and the automatic door lock mechanism is short-circuited or disconnected, the power cannot be supplied from the main power supply to the automatic door lock mechanism. It is conceivable to separately provide a spare wiring for connecting the power supply and the automatic door lock mechanism, but this is not preferable because the wiring route becomes complicated.

In Patent Document 1, an electric double layer capacitor (hereinafter, referred to as EDLC) as a power storage device, a collision detection unit that detects a collision of a vehicle, and a signal from the collision detection unit are forcibly released from the door lock. An auxiliary power supply device having a door lock release switch is disclosed. When the vehicle collision is detected by the collision detection means, the door lock release switch is driven by the electric power supplied from the EDLC, and the door lock is released.

Japanese Patent No. 6074586

A power storage device such as an EDLC or a secondary battery has a predetermined internal resistance. In the auxiliary power supply device including the power storage device as the auxiliary power supply, the internal capacity of the power storage device is set when setting the battery capacity (electrostatic capacity in the case of EDLC) of the storage battery for driving the electrical equipment such as the automatic door lock mechanism. It is necessary to consider the voltage drop due to resistance. In particular, the EDLC has a large internal resistance when it is used in a low temperature environment or when it deteriorates due to aging or the like. In consideration of this, it becomes necessary to increase the storage capacity of the power storage device (electrostatic capacitance of EDLC).

However, increasing the storage capacity of the power storage device leads to an increase in the size of the power storage device and an increase in cost.

The present invention has been made to solve the above problems, and an object of the present invention is a power storage device having a small capacity, which is capable of driving an electrical component when the main power supply is cut off. A power supply device and a power supply method are provided.

The vehicle auxiliary power supply device according to the present invention includes a power storage device connected to a main power supply of the vehicle. Then, a detection unit that detects an emergency, and a control unit that supplies a DC voltage from the power storage device by dividing the electric component driven when the emergency is detected into a plurality of parts with a time difference, Characterized by having

The auxiliary power supply device for a vehicle of the present invention reduces the drive current from the power storage device by supplying a DC voltage from the power storage device by dividing the plurality of electrical components with a time difference and supplying an internal resistance of the power storage device. By reducing the influence of the above, it is possible to suppress a decrease in the terminal voltage of the power storage device while the current is flowing in the electric load, and to suppress a decrease in the electric energy stored in the power storage device. By effectively utilizing the electric energy stored in the power storage device having a small capacity, it is possible to drive the electrical component when the main power supply is cut off.

1 is a circuit diagram of a vehicle auxiliary power supply device and a drive waveform diagram of a door lock motor according to a first embodiment of the present invention. Equivalent circuit of the EDLC of the vehicle auxiliary power supply device of the first embodiment Discharge characteristic diagram of the EDLC of the vehicle auxiliary power supply device of the first embodiment A circuit diagram of a vehicle auxiliary power supply device and a drive waveform diagram of a door lock motor according to a second embodiment. Discharge characteristic diagram of the EDLC of the vehicle auxiliary power supply device of the second embodiment Circuit diagram of vehicle auxiliary power supply device according to reference example and drive waveform diagram of door lock motor EDLC discharge characteristic diagram of vehicle auxiliary power supply of reference example

[First Embodiment]
FIG. 1 is a circuit diagram of a vehicle auxiliary power supply device according to a first embodiment of the present invention, and a drive waveform diagram of a door lock motor.
The main power source 12 is a 12V main battery for starting the engine of the vehicle and supplying electric power to electric components. The vehicle auxiliary power supply device 40 includes a power storage device 20, a detection unit 14, and a control unit 30. Power storage device 20 is supplied with power from main power supply 12. The power storage device 20 includes DC-DC converters 22 and 24 and an EDLC (electric double layer capacitor) 26. The six unit cells forming the EDLC 26 each have an electrostatic capacity of 21F, an internal resistance of 20 mΩ, and a maximum charging voltage of 2.5V. The internal resistance (combined resistance) of the power storage device is 120 mΩ, the electrostatic capacity (combined capacity) C is 3.5 F, and the maximum charging voltage E is 15.0 V. The total capacitance of the six unit cells is 126F. The DC-DC converter 22 boosts the 12V voltage from the main power supply 12 to the charging voltage of the EDLC 26. The DC-DC converter 24 adjusts the voltage drop when the load voltage of the EDLC 26 is supplied and supplies it to the load side.

The detection unit 14 detects the voltage supplied from the main power supply 12. The detection unit 14 outputs a detection signal to the control unit 30 side when the voltage supplied from the main power supply 12 is cut off. In the first embodiment, the detection unit 14 detects the voltage supplied from the main power source 12, but instead, it is possible to detect an impact such as a vehicle collision and output a detection signal to the control unit. Is. The control unit 30 controls the switch 32L and the switch 32R. The switch 32L supplies electric power to the door lock motor 16FL provided at the left front door and the door lock motor 16RL provided at the left rear door. The switch 32R supplies electric power to the door lock motor 16FR provided on the front right door and the door lock motor 16RR provided on the rear right door.

The vehicle of the first embodiment includes an automatic door lock mechanism (not shown) that automatically locks the door when the vehicle exceeds a predetermined speed (for example, 5 km/hour), and when the vehicle exceeds the predetermined speed, the automatic door lock mechanism is provided. The mechanism includes a door lock motor 16FL provided on the left front door, a door lock motor 16FR provided on the right front door, a door lock motor 16RL provided on the left rear door, and a door lock motor provided on the right rear door. Drive 16RR and lock each door.

Here, the operation of the vehicle auxiliary power supply device 40 of the first embodiment when the voltage supplied from the main power supply 12 is cut off will be described.
When detecting that the voltage supplied from the main power supply 12 is cut off, the detection unit 14 outputs a detection signal to the control unit 30. The control unit 30 turns on the switch 32R for 400 ms to supply electric power (12V, 5A×2=10A) to the door lock motor 16FR provided on the right front door and the door lock motor 16RR provided on the right rear door. .. That is, (12V, 5A) is supplied to the door lock motor 16FR, and (12V, 5A) is supplied to the door lock motor 16RR. As a result, the door lock between the right front door and the right rear door is released. Subsequently, the control unit 30 turns on the switch 32L for 400 ms and supplies electric power (12V, 5A×2=10A) to the door lock motor 16RL provided on the left rear door and the door lock motor 16FL provided on the left front door. To do. As a result, the door lock between the left front door and the left rear door is released. As the output waveform of the vehicle auxiliary power supply device, electric power of (12V, 5A×2=10A) is output for 800 ms.

FIG. 2 is an equivalent circuit of the EDLC of the vehicle auxiliary power supply device of the first embodiment.
The internal resistance (combined resistance) R is 120 mΩ, the internal voltage of the EDLC is represented by E, the input voltage of the ideal DC-DC converter is represented by V, and the input current of the EDLC is represented by I. The EDLCN voltage drop is boosted by the ideal DC-DC converter, and a voltage of 12 V is applied to the load (door lock motor).

FIG. 3 is a discharge characteristic diagram of the EDLC of the vehicle auxiliary power supply device of the first embodiment. This figure is a simulation result.
The left vertical axis represents voltage, the right vertical axis represents current, and the horizontal axis represents time.
While the internal voltage E of the EDLC drops from 15.00V to 10.7V, the input voltage V of the ideal DC-DC converter drops from 12.7V to 5.4V, and a current of 10A or more is output for 1.22 seconds. It That is, the EDLC of the first embodiment can output a 12V voltage for 1.22 seconds.

In the first embodiment, the load is divided into two and the current value is reduced to half, so that the voltage drop at the internal resistance of the EDLC, which is proportional to the square of the current value, is suppressed. By decreasing the current and reducing the influence of the internal resistance of the EDLC, it is possible to suppress the decrease in the terminal voltage of the EDLC while the current is flowing in the electric load, and to suppress the decrease in the electric energy stored in the EDLC. By effectively utilizing the electric energy stored in the EDLC having a small capacity, it is possible to drive the electric component (door lock motor) when the main power supply is cut off.

[Second Embodiment]
FIG. 4 is a circuit diagram of a vehicle auxiliary power supply device according to a second embodiment of the present invention and a drive waveform diagram of a door lock motor.
The vehicle auxiliary power supply device of the second embodiment has the same configuration as the vehicle auxiliary power supply device of the first embodiment. However, in the vehicle auxiliary power supply device of the second embodiment, the control unit 30 controls the switch 32FL, the switch 32RL, the switch 32RR, and the switch 32FR. The switch 32FL supplies power to the door lock motor 16FL provided on the left front door. The switch 32RL supplies electric power to the door lock motor 16RL provided on the left rear door. The switch 32RR supplies electric power to the door lock motor 16RR provided on the right rear door. The switch 32FR supplies electric power to the door lock motor 16FR provided on the front right door.

The vehicle auxiliary power supply device of the second embodiment includes the EDLC (electric double layer capacitor) 26 of the power storage device 20. Each of the four unit cells forming the EDLC 26 has an electrostatic capacity of 21F, an internal resistance of 20 mΩ, and a maximum charging voltage of 2.5V. The internal resistance (combined resistance) of the power storage device is 80 mΩ, the electrostatic capacity (combined capacity) C is 5.25 F, and the maximum charging voltage E is 10.0 V. The total capacitance of the four unit cells is 84F.

Here, the operation of the vehicle auxiliary power supply device 40 of the second embodiment when the voltage supplied from the main power supply 12 is cut off will be described.
When detecting that the voltage supplied from the main power supply 12 is cut off, the detection unit 14 outputs a detection signal to the control unit 30. The control unit 30 turns on the switch 32FR for 400 ms, supplies power (12 V, 5 A) to the door lock motor 16FR provided on the right front door, and releases the door lock on the right front door. Subsequently, the control unit 30 turns on the switch 32FL for 400 ms, supplies electric power (12V, 5A) to the door lock motor 16FL provided on the left front door, and releases the door lock on the left front door. The control unit 30 turns on the switch 32RR for 400 ms, supplies electric power (12 V, 5 A) to the door lock motor 16RR provided on the right rear door, and releases the door lock on the right rear door. Finally, the control unit 30 turns on the switch 32RL for 400 ms, supplies electric power (12V, 5A) to the door lock motor 16RL provided on the left rear door, and releases the door lock on the left rear door. As the output waveform of the vehicle auxiliary power supply device, electric power of (12V, 5A) is output for 1600 ms.

FIG. 5 is a discharge characteristic diagram of the EDLC of the vehicle auxiliary power supply device of the second embodiment. This figure is a simulation result.
While the internal voltage E of the EDLC decreases from 10.00V to 6.7V, the input voltage V of the ideal DC-DC converter decreases from 8.9V to 4.6V, and a current of 5A or more is output for 2 seconds or more. .. That is, the EDLC of the second embodiment can output a 12V voltage for 2 seconds or more.

In the second embodiment, the load is divided into four and sequentially supplied to reduce the current value to 1/4, so that the voltage drop in the internal resistance of the EDLC proportional to the square of the current value is suppressed.

[Reference example]
FIG. 6 is a circuit diagram of a vehicle auxiliary power supply device according to a reference example of the present invention and a drive waveform diagram of a door lock motor.
The vehicle auxiliary power supply device of the reference example has the same configuration as the vehicle auxiliary power supply device of the first embodiment. However, in the vehicle auxiliary power supply device of the reference example, the control unit 30 controls the switch 32. The switch 32 includes a door lock motor 16FL provided on the left front door, a door lock motor 16RL provided on the left rear door, a door lock motor 16FR provided on the right front door, and a door lock motor 16RR provided on the right rear door. Supply power.

The vehicle auxiliary power supply device of the reference example includes the EDLC (electric double layer capacitor) 26 of the power storage device 20. Each of the nine unit cells forming the EDLC 26 has a capacitance of 21F, an internal resistance of 20 mΩ, and a maximum charging voltage of 2.5V. The internal resistance (combined resistance) of the power storage device is 180 mΩ, the electrostatic capacity (combined capacity) C is 2.33 F, and the maximum charging voltage E is 22.5 V. The total capacitance of the nine unit cells is 189F.

Here, the operation of the vehicle auxiliary power supply device 40 of the reference example when the voltage supplied from the main power supply 12 is cut off will be described.
When detecting that the voltage supplied from the main power supply 12 is cut off, the detection unit 14 outputs a detection signal to the control unit 30. The control unit 30 turns on the switch 32 for 400 ms, the door lock motor 16FL provided on the left front door, the door lock motor 16RL provided on the left rear door, and the door lock motor 16RR provided on the right rear door, Electric power (12V, 5A×4=20A) is supplied to the door lock motor 16FR provided on the front right door. As a result, the door lock with the left front door, the left rear door, the right front door, and the right rear door is released at the same time. As the output waveform of the vehicle auxiliary power supply device, electric power of (12V, 5A×4=20A) is output for 400 ms.

FIG. 7 is a discharge characteristic diagram of the EDLC of the vehicle auxiliary power supply device of the reference example. This figure is a simulation result.
While the internal voltage E of the EDLC is reduced from 22.50V to 18.8V, the input voltage V of the ideal DC-DC converter is reduced from 18.4V to 10.3V and a current of 10A or more is output for 0.55 seconds. It That is, the EDLC of the reference example can output a 12V voltage for 0.56 seconds.

The total load of the reference example and the first and second embodiments is the same. In order to simultaneously unlock the doors as in the reference example, nine cells are required in the EDLC, whereas in the second embodiment, unlocking can be performed with four cells. In the first embodiment, unlocking can be performed with seven cells. As described above, in the first and second embodiments, the number of cells of the EDLC can be reduced, so that the vehicle auxiliary power supply device can be configured at a low price. Further, the vehicle auxiliary power supply device can be downsized.

In the above-described embodiment, the vehicle auxiliary power supply device that drives the door lock motor is illustrated as the load, but the load is, for example, a safety device that drops the high voltage stored in the capacitor or the like to the resistance or the like in an emergency. Is also applicable.

12 Main power supply 14 Detection unit 16FL Door lock motor 16FR Door lock motor 16RL Door lock motor 16RR Door lock motor 20 Electric storage device 26 EDLC
24 DC-DC converter 30 Control unit 40 Vehicle auxiliary power supply device

Claims (7)

A vehicle auxiliary power supply device comprising a power storage device connected to a main power supply of a vehicle,
A detection unit that detects an emergency,
An auxiliary power supply for a vehicle, comprising: a control unit that divides a plurality of electrical components that are driven when an emergency is detected and supplies a DC voltage from the power storage device with a time difference. apparatus. The vehicle auxiliary power supply device according to claim 1,
The vehicle auxiliary power supply device, wherein the main power supply is cut off in the emergency. The vehicle auxiliary power supply device according to claim 1,
An auxiliary power supply device for a vehicle, which detects a vehicle collision in the emergency. The vehicle auxiliary power supply device according to any one of claims 1 to 3,
An auxiliary power supply device for a vehicle, comprising: a transformer that transforms a DC voltage from the power storage device and supplies the DC voltage to the electrical component. The vehicle auxiliary power supply device according to claim 4,
The vehicle auxiliary power supply device, wherein the power storage device is an electric double layer capacitor. The vehicle auxiliary power supply device according to any one of claims 1 to 5,
The electrical component is a door lock actuator,
The door lock actuator locks the door in a specific traveling state,
The auxiliary power supply device for a vehicle, wherein the control unit divides the door lock actuator into a plurality of parts to provide a time difference and supply a DC voltage from the power storage device to sequentially unlock the doors. A method of supplying power from an electricity storage device to an electrical component driven in an emergency,
To detect an emergency,
When the emergency is detected, a plurality of electric components to be driven are divided into a plurality of parts with a time difference, and a DC voltage is supplied from the power storage device.

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