JP2000142275A - Battery exhaustion preventive device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely prevent battery exhaustion by cutting off a power circuit of a backup memory at preset time according to a travel distance by driving a first power source cut means after the lapse of a preset cut waiting time after turning off an ignition key switch when an integrating travel distance is not more than a prescribed value. SOLUTION: A first power source cut means timely cuts off or electrically conducts a first power circuit 5 to a backup memory 10 of a vehicular electronic control circuit from a battery 4. A second power source cut means timely cuts off or electrically electrical conducts a second power circuit 7 of a cabin inside lamp 6 from the battery 4. A control means drives at least the first power source cut means among the first power source cut means and the second power source cut means after preset cut waiting time passes after turning off an IG switch 3 when an integrating travel distance from a travel distance calculating means is not more than a preset value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for preventing a battery from running out of a vehicle, and more particularly to a device for preventing a battery from running out of a vehicle suitable for use in a vehicle configured to supply power from a battery power source of the vehicle to an electronic control unit for the vehicle. Related to the device.

[0002]

2. Description of the Related Art A battery mounted on a vehicle is charged when the engine is driven, and is consumed by various lightings, various interior devices, and engine accessories mounted on the vehicle. Such a battery discharges spontaneously when left for a long period of time, and in particular, when various interior lamps and the like are left to be turned off, the battery runs out. Heretofore, there has been known a battery exhaustion prevention device which can prevent the battery exhaustion caused by forgetting to turn off such an interior lamp.

[0003] This type of battery rising prevention device is designed to provide a power supply cut-off waiting time when a vehicle is in a new vehicle logistics or a new vehicle storage, that is, when the vehicle is in an integrated traveling distance considered to be before delivery, for example, about 24 km. The power supply cut-off waiting time after delivery of the above-described integrated mileage is set in advance, and each time the ignition key switch of the vehicle is turned off, the cut-off time set in advance for the current mileage is set. The waiting time elapses, and when it elapses, the power supply circuit of the interior lamp is shut off to prevent the battery from running out. In this case, when the vehicle is in the integrated mileage range before delivery, the cut wait time is as short as about 3 minutes, and when the vehicle is in the integrated mileage region after delivery, it is about 20 minutes, that is, the cut wait time does not cause a problem during normal use. The power supply circuit of the interior lamp is shut off to prevent the battery from running out due to forgetting to turn off the interior lamp.

[0004]

The above-described battery running-out prevention device cuts off the power supply circuit of the interior lamp without waste in the cut-off waiting time suitable for the use state estimated from the integrated traveling distance of the vehicle, and the battery running-out. However, the dead battery is caused by other factors other than forgetting to turn off the interior lamp. For example, various types of vehicle electronic control devices are used in vehicles for engine control, various running state controls, control of interior equipment, and the like. Japanese Patent Laid-Open Publication No. Hei 10-80070 discloses an electronic control unit that can reduce the power consumption of the electronic control unit for a vehicle when the vehicle is stopped.

As apparent from these, the backup memory of the vehicle electronic control device consumes a low current to maintain the standby state even when the ignition key is turned off.
If the low current supplied to such a backup memory continues to flow for a long period of time, the battery may run down, which is a problem. SUMMARY OF THE INVENTION It is an object of the present invention to prevent a battery from running down in a vehicle that can accurately prevent the battery from running up by shutting off at least a power supply circuit of the backup memory among two power supply circuits of a backup memory and a vehicle interior lamp according to a traveling distance. Another object of the present invention is to provide a device for preventing a battery from running out of a vehicle, which can prevent a battery from running out due to forgetting to turn off a vehicle interior lamp.

[0006]

In order to achieve the above object, according to the first aspect of the present invention, an integrated travel distance of a vehicle is calculated by a travel distance calculating means, and the ignition of the vehicle is performed by an ignition key switch on / off state detecting means. Detecting the on / off state of the key switch, disposing the first power supply cut means so as to cut off the power supply circuit from the battery of the vehicle to the backup memory of the electronic control unit for the vehicle;
The second power supply cut-off means is provided so as to be able to cut off the power supply circuit from the battery to the vehicle interior lamp. When the integrated travel distance is equal to or less than a predetermined value, the control power supply means sets a cut-off waiting time after the ignition key switch is turned off. After the lapse of time, at least the first power supply cutting means of the first power supply cutting means and the second power supply cutting means is driven. Here, when the accumulated traveling distance is equal to or less than a predetermined value, at least the first power supply cut-off means is driven after a lapse of a set cut-off waiting time after the ignition key switch is turned off. For this reason, in a mileage range in which the accumulated mileage is equal to or less than a predetermined value, for example, in a mileage range in which the data is not required to be held in the backup memory before the vehicle is delivered, unnecessary power supply to the backup memory is eliminated and the battery runs out. In a travel distance range equal to or greater than a predetermined value, wasteful power supply to the vehicle interior lamp can be eliminated, and the running out of the battery can be more reliably prevented. The control means may calculate an integrated continuous traveling distance, and determine that the vehicle has been delivered if the integrated continuous traveling distance exceeds a predetermined value in a traveling distance range where the vehicle may be delivered. In this case, the reliability of the power supply cut control is particularly improved.

According to a second aspect of the present invention, in the vehicle battery prevention device according to the first aspect, in particular, the control means determines a plurality of integrated mileage areas and a cut waiting time for each of the integrated mileage areas. The first power supply cut-off means and / or the second power supply cut-off means are driven when an elapsed time after the ignition key switch is turned off exceeds a set cut-off waiting time at the current accumulated traveling distance. In this case, the travel distance range and the set cut waiting time corresponding thereto are obtained, and after the set cut wait time at the current travel distance has elapsed, the first power supply cut unit and / or the second power cut unit is driven. For this reason, the traveling distance area is divided into a large number of areas, different power cut conditions are set for each traveling distance area, and the power supply cut to the backup memory and the power supply cut processing to the vehicle interior lamp are performed for each traveling distance area. Can be selectively set, the power supply cut suitable for each traveling distance range can be performed, and the running out of the battery can be more reliably prevented.

[0008] The invention of claim 3 is claim 1 or claim 2.
In the vehicle battery prevention device described above,
A driver door opening / closing detecting means for detecting opening / closing of a driver's door; and current detecting means provided in a power supply circuit from the battery to a vehicle interior lamp. The second power supply cut-off means is driven when the signal from the means and / or the signal from the current detection means is input and the elapsed time after the ignition key switch is turned off exceeds a set elapsed time. In this case, the power supply to the vehicle interior lamp is cut off when the driver cuts the driver's door opening / closing operation and / or the power supply to the vehicle interior lamp and the set cut waiting time elapses after the ignition key switch is turned off. By selectively combining this process with a process for eliminating unnecessary power supply to the backup memory and the vehicle interior lamp according to the mileage range, it is possible to more reliably prevent the battery from running down. .

[0009]

1 and 2 show a device for preventing a battery from running out of a vehicle to which the present invention is applied. The battery rising prevention device 1 for a vehicle divides a mileage range into a plurality of mileage ranges, here, three mileage ranges of 0 to 30 miles, 30 to 90 miles, and 90 miles or more, and different power cuts for each mileage range. The conditions are set, and the power supply cut to the backup memory 10 and the power supply cut to the vehicle interior lamp 6 are selectively set for each traveling distance area.

Here, a device 1 for preventing the battery from running out of the vehicle is provided.
Has an electric circuit C as shown in FIG. The electric circuit C includes a battery 4, an output terminal 11 connected thereto via a fuse box 9, a control unit 12 connected to the output terminal 11, an output terminal 11, and a backup memory of the vehicle electronic control unit ECU. (ROM) 1
0, a keep relay [1] 13 disposed in the first power supply circuit 5 and serving as first power supply cut-off means A3 described later, an output terminal 11, and a vehicle interior lamp 6.
, A keep relay [2] 14 disposed in the second power supply circuit 7 and forming a second power supply cut-off means A4 described later, and outputs a vehicle speed pulse signal v to the control unit 12. A vehicle speed pulse signal generator 2, an ignition key switch (hereinafter simply referred to as an IG switch) 3 for outputting an on / off signal (ACC position signal) IG to the control unit 12, and a driver door for outputting a switching signal ds to the control unit 12 A switch 8.

The vehicle electronic control unit ECU has an engine control function of the vehicle and a control function of various running states, and has a first function of connecting the battery 4 and the backup memory (ROM) 10.
A keep relay [1] 13 is provided in the power supply circuit 5.
The output terminal 131 side of the keep relay [1] 13 is branched, though not shown, and is connected to a plurality of vehicle electronic control devices constituting other vehicle control means (not shown). In FIG. 1, an output terminal 141 of a keep relay [2] 14 is connected to a pair of vehicle interior lamps 6,6.
The output terminal 141 side of the keep relay [2] 14 is branched, not shown, and is also configured to be branched and connected to a plurality of other vehicle interior lamps, not shown.

The control unit 12 includes a well-known microcomputer (hereinafter simply referred to as a microcomputer) 15, a current detection circuit 16 that detects a current value signal i of the second power supply circuit 7 and outputs the current value signal i to the microcomputer 15, A relay switching circuit 17 and a second keep relay switching circuit 18 are provided. 1st keep relay switching circuit 1
7 energizes the solenoid 132 of the keep relay [1] 13 in accordance with the drive signal of the microcomputer 15 to make the normally closed contact 13
3 is opened and the first power supply circuit 5 is cut off. Second
The keep relay switching circuit 18 is operated by a solenoid 142 of the keep relay [2] 14 in accordance with a drive signal of the microcomputer 15.
Is excited to switch the normally closed contact 143 to open, and the second power supply circuit 7 is cut off. Here, as shown in FIG. 2, the vehicle battery dead-up prevention device 1 includes a traveling distance calculating unit A1.
IG switch on / off state detecting means A2, first power supply cutting means A3, second power supply cutting means A4, driver's door opening / closing detecting means A5, current detecting means A6, and control means A7. In particular, the microcomputer 15 is configured to perform the function as the control unit A7.

The running distance calculating means A1 calculates the total running distance N of a vehicle (not shown). The microcomputer 15 counts the vehicle speed pulse signal v from the vehicle speed pulse signal generator 2 to calculate the total running distance N. The IG switch ON / OFF state detecting means A2 includes the IG switch 3, and outputs an ON signal IG to the microcomputer 15 when the IG switch reaches the ACC position from the OFF position. The first power supply cutoff means A3 comprises a keep relay [1] 13, and cuts off or cuts off the first power supply circuit 5 from the battery 4 as a power supply to the backup memory 10 of the vehicle electronic control unit ECU in a timely manner or conducts. I do.

The second power supply cut-off means A4 comprises a keep relay [2] 14, and cuts off or conducts the second power supply circuit 7 from the battery 4 to the vehicle interior lamp 6 in a timely manner. The driver's door opening / closing detecting means A5 includes a driver's door switch 8, detects opening / closing of a driver's door (not shown), and outputs a switching signal ds to the microcomputer 15. The main part of the current detection means A6 is constituted by the current detection circuit 16, and is disposed in the second power supply circuit 7 connecting the battery 4 and the vehicle interior lamp 6, and detects the current value signal i of the second power supply circuit 7. And outputs it to the microcomputer 15.

The function as the control means A7 is the microcomputer 15
Done in The control means A7 includes a traveling distance calculating means A
When the integrated travel distance N from 1 is equal to or less than a predetermined value,
After the set cut waiting time Tn after the IG switch 3 is turned off, the first power cut means A3 and the second power cut means A
At least one of the first power supply cutting means A3 is driven. In particular, here, the integrated travel distance range is set to a large number (0 to be described later).
3 to 30 miles, 30 to 90 miles, 90 miles or more
In this case, each cut waiting time Tn (3 minutes, 36 hours described later) is set in advance for each accumulated traveling distance N, and the elapsed time t after the IG switch 3 is turned off is the current accumulated traveling distance. When the set cut waiting time Tn corresponding to N has elapsed, the first power cut means A3 and the second power cut means A4 are driven together. Further, the control means A7
Is a switching signal d from the driver's door opening / closing detecting means A5.
s and / or when the current value signal i is input from the current detecting means A6 and the elapsed time t after the IG switch 3 is turned off exceeds the set cut waiting time Tn, the second power supply cutting means A
4 also functions to cut off the power supply circuit 7 to the vehicle interior lamp 6 by driving the vehicle interior lamp 6.

The microcomputer 15 as such control means A7 controls the switching between the keep relay [1] 13 and the keep relay [2] 14 in accordance with the power supply switching control processing routine shown in FIGS. 3, 4, and 5. The main routine here is executed when the IG switch 3 is turned on. Here, the process proceeds to a data fetching process a1, where the data of each driving state is fetched, a post-delivery flag FLG1 described later is initially set to off (= 0), and then the process proceeds to an IGON integrated time calculating process a2. Here, every time the IG switch is turned on, I
The GON integrated time is calculated and the latest value is stored. Next, an integrated travel distance calculation process a3 is executed. Here, when the vehicle speed pulse signal v is input from the vehicle speed pulse signal generator 2, the vehicle speed pulse signal v is counted to calculate the integrated travel distance N, and the latest value is stored. I do. Next, a continuous running distance calculation process a4 is executed. Here, when the vehicle speed pulse signal v is input, the continuous running distance is calculated while the level of the vehicle speed pulse signal v is equal to or higher than the set value, and the latest value is stored. On the other hand, when the IG switch 3 is turned off, a pre-delivery switching routine of FIG. 4 and a post-delivery switching routine of FIG. 5 are executed in this order by a predetermined time interruption.

When the pre-delivery switching routine of FIG. 4 is reached, a post-delivery flag FL for post-delivery determination is made in step s1.
It is determined whether or not G1 is ON, and the routine returns after delivery, and proceeds to step s2 before delivery. Here, if the IG switch is on, this process ends, and if it is off, the process proceeds to step s3. In step s3, the latest IGON integrated time is fetched, and it is determined whether or not this value is 10 hours or more. In the above, it is considered that the vehicle has been delivered, and in step s4, the keep relay [1] 1
3 and the keep relay [2] 14 are switched to non-excitation, that is, the first power supply circuit 5 and the second power supply circuit 7 of both keep relays.
Is kept in a continuous conduction (ON), the flag FIG1 is turned on after the vehicle is delivered, and the routine returns.

On the other hand, if the accumulated IGON time is less than 10 hours, the process proceeds to step s5, where the latest accumulated traveling distance N is fetched, it is determined whether or not this value is 30 miles or less. If yes, go to step s6, otherwise go to step s7. In step s6, it is determined whether or not the latest accumulated traveling distance N is equal to or less than 90 miles.
If it exceeds the mileage, it is considered that the vehicle has been delivered, and the process proceeds to step s4. If it is less than 90 miles, the process proceeds to step s8. Here, it is between 30 and 90 miles,
Further, the latest continuous mileage at the present time is taken in, and it is determined whether or not the mileage is 35 miles or more. If the mileage is 35 miles or more, it is considered that the vehicle has been delivered, and the process proceeds to step s4. Here, it is assumed that the vehicle is under 35 miles before delivery. However, considering the possibility after delivery, wait 36 hours after the IG switch is turned off continuously. And keep relay [1] 13 and keep relay [2] 1
4 is switched to excitation (on), that is, the first power supply circuit 5 and the second power supply circuit 7 of both keep relays are continuously cut off (off).
, And turns off (= 0) the flag FIG. 1 after delivery, and returns to the main routine. In this case, it is considered that the vehicle has not been delivered yet, and at this time, there is no need to store data in the backup memory 10 of the ECU, and power supply to the backup memory 10 and the vehicle interior lamp 14 can be reliably cut to prevent the battery from running out. Moreover, if the IG switch 3 is turned on again before the lapse of 36 consecutive hours after the IG switch is turned off, this process is canceled and the process returns to the main routine.

Next, in step s5, when the latest accumulated mileage N is determined to be 30 miles or less and the process reaches step s7, the latest continuous mileage is fetched, and it is determined whether this value is 10 miles or more. If it is 10 miles or more, proceed to step s9. Here, considering the possibility of delivery,
Wait for 36 consecutive hours after the G switch is turned off. If it does not reach this point, it is determined that the vehicle has not been delivered, the power supply circuits 5 and 7 of both the keep relays are continuously cut off (off), and the process returns to the main routine. I do. On the other hand, in step s7,
If it is determined to be less than 10 miles and the process proceeds to step s10, it is determined that the vehicle has not been delivered, and three minutes after the IG switch is turned off, the keep relay [1] 13 and the keep relay [2] 14 are excited (ON). ), That is, the power supply circuits 5 and 7 of both keep relays are continuously cut off (off), and the flag FIG1 is turned off (= 0) after delivery.
And returns to the main routine. Before the vehicle is delivered, there is no need to store data in the backup memory 10 of the ECU, and the power supply to the backup memory 10 and the vehicle interior lamp 14 is reliably cut off early to prevent the battery from running out.

Next, when the post-delivery switching routine of FIG. 5 is reached, it is determined in step b1 whether or not the after-delivery flag FLG1 for after-delivery determination is on, and before returning, the routine returns.
After delivery, the process proceeds to step b2. Here, it is determined whether or not the IG switch is off. If the IG switch is on, this process ends. If the IG switch is off, the process proceeds to step b3. Step b
At 3, the current value signal i of the second power supply circuit 7 from the current detection circuit 16 is detected, and the process proceeds to step b4 when the current is being supplied and to step b5 when the current is not supplied. In step b5, the vehicle interior lamp 6 is turned off (turned off) by de-energization, it is regarded as a normal state, and the keep relay [2] 14 is switched to non-excitation.
The second power supply circuit 7 is kept in a continuous conduction (ON), the power supply cut system is canceled, and the process returns. Since the keep relay [1] 13 has the flag FLG1 = 1 after delivery, the keep relay [1] 13 is, of course, switched to non-excitation (ON) and held.

On the other hand, in step b3, the current value signal i of the second power supply circuit 7 is detected, and when the current reaches the step b4 as energizing, the switching signal ds of the driver's seat door switch 8 is changed from ON to OFF. It is determined whether or not the switching change has been completed. If the switching change has not been completed, the process proceeds to step b6.
If completed, the process proceeds to step b7. Before the switching change is completed in step b6, is the door closing process delayed?
The half-door is considered to be left unattended, and a 30-minute cut waiting time is counted. If the door closing process is not performed even if the waiting time is reached, it is considered that the driver's door switch 8 has failed, etc. [2] Hold 14 at excitation (off), keep second power supply circuit 7 at continuous interruption (off), and return to the main routine. In this case, the energized vehicle interior lamp 6 is turned off, and the power supply to the vehicle interior lamp 6 is reliably cut off early to prevent the battery from running out. In addition, it is delivery,
At this time, since the backup memory 10 of the ECU is in use, the first power supply circuit 5 of the backup memory 10 is used.
Is not naturally performed.

From step b4, the driver's door switch 8
When it is determined that the switching signal ds has changed from on to off and the process proceeds to step b7, the keep relay [2] 14 is switched to excitation (off) after a cut waiting time of 3 minutes, and the second power supply circuit 7 is kept off (off), and the process returns to the main routine. In this case, since the occupant has detected the current value signal i even though the passenger has exited, it is considered that the interior lamp 6 has been forgotten to be turned off, and the power supply is cut off early to prevent the battery from running out. Note that the vehicle has already been delivered, and at this time, the backup memory 1
0 is in use, so that the first
The power supply circuit 5 is not interrupted.

As described above, the vehicle battery rising prevention device 1 prevents the backup memory 10 of the plurality of vehicle electronic control units ECU from consuming power before the vehicle is delivered. Prevent power consumption due to forgetting to turn off, and reduce unnecessary power consumption of battery 4,
Poor starting of the vehicle due to a dead battery can be reliably prevented. In the above-mentioned process, the accumulated mileage range is divided into three ranges of 0 to 30 miles, 30 to 90 miles, and 90 miles or more, and the cut waiting time suitable for each accumulated mileage range is set. It is also possible to classify the accumulated mileage range. In this case, the same operation and effect as those of the battery running-down prevention device 1 of the vehicle shown in FIG. 1 can be obtained.

Further, the vehicle running-out prevention device 1 of FIG. 1 compares the integrated continuous mileage with a set value in both the integrated mileage ranges of 0 to 30 miles and 30 to 90 miles (steps s7 and s9). Has improved the reliability of determining whether or not the vehicle has already been delivered.However, in some cases, the comparison process with the set value of the integrated continuous mileage may be omitted, and the power supply cut control may be simplified. good.

[0025]

As described above, according to the first aspect of the present invention, when the integrated mileage is equal to or less than a predetermined value, at least the first power supply cut-off means is driven after a lapse of a set cut-off wait time after an ignition key switch is turned off. In addition, since the power supply to the backup memory is cut, in a mileage range where the integrated mileage is equal to or less than a predetermined value, unnecessary power supply to the backup memory can be prevented to prevent the battery from running down, and a mileage range equal to or more than the predetermined value can be prevented. Thus, wasteful power supply to the vehicle interior lamp can be eliminated, and the battery can be more reliably prevented from running out.

The invention according to a second aspect is characterized in that a plurality of integrated mileage areas and a cut waiting time for each of the integrated mileage areas are set in advance, and the current mileage area and the set cut waiting time corresponding thereto are set. And the first power supply cut-off means and / or the second power supply cut-off means are driven after a lapse of the set cut-off waiting time at the current traveling distance. For this reason, the traveling distance area is divided into a large number of areas, different power cut conditions are set for each traveling distance area, and the power supply cut to the backup memory and the power supply cut processing to the vehicle interior lamp are performed for each traveling distance area. Can be selectively set, the power supply cut suitable for each traveling distance range can be performed, and the running out of the battery can be more reliably prevented.

[0027] The invention of claim 3 is particularly advantageous when the signal from the driver's door opening / closing detecting means and / or the signal from the current detecting means is input and the elapsed time after the ignition key switch is turned off exceeds the set elapsed time. In this case, when the driver's door is opened / closed and / or when power is supplied to the vehicle interior lamp, the set cut waiting time passes after the ignition key switch is turned off. By cutting the power supply to the vehicle interior lamp, it is possible to prevent the battery from running out,
By selectively combining this processing with processing for eliminating unnecessary power supply to the backup memory and the vehicle interior lamp according to the traveling distance range, it is possible to more reliably prevent the battery from running down.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram of a vehicle battery prevention device of the present invention.

FIG. 2 is a functional block diagram of the battery running-down prevention device of the vehicle shown in FIG. 1;

FIG. 3 is a flowchart of a main routine of a power supply switching control process used by the vehicle battery prevention device of FIG. 1;

FIG. 4 is a flowchart of a pre-delivery switching routine of a power supply switching control process used by the vehicle battery prevention device of FIG. 1;

FIG. 5 is a flowchart of a post-delivery switching routine of a power supply switching control process used by the vehicle battery prevention device of FIG. 1;

[Explanation of symbols]

 REFERENCE SIGNS LIST 3 IG switch 4 battery 5 first power circuit 6 interior lamp 7 second power circuit 10 backup memory A1 mileage calculating means A2 IG switch on / off state detecting means A3 first power cut means A4 second power cut means A5 driver's seat door Opening / closing detecting means A6 Current detecting means A7 Control means N Total running distance Tn Cut waiting time N Total running distance

Claims (3)

[Claims] 1. A mileage calculating means for calculating an integrated mileage of a vehicle, an ignition key switch on / off state detecting means for detecting an on / off state of an ignition key switch of the vehicle, and a backup of a vehicle electronic control device from a battery of the vehicle. The first to cut the power supply circuit to the memory
A power supply cutoff means, a second power supply cutoff means for cutting off a power supply circuit from the battery to a vehicle interior lamp, and the second cutoff means after a lapse of a set cutoff wait time after an ignition key switch is turned off when the integrated traveling distance is a predetermined value or less. An apparatus for preventing a battery from running out of a vehicle, comprising: a control means for driving at least the first power supply cut-off means of the first power supply cut-off means and the second power supply cut-off means. 2. The control means according to claim 1, wherein a plurality of integrated travel distance ranges and a cut waiting time for each of the integrated travel distance ranges are set in advance, and an elapsed time after the ignition key switch is turned off is a current integrated travel range. 2. The apparatus according to claim 1, wherein the first power supply cut-off means and / or the second power supply cut-off means are driven when a set cutoff wait time at a distance has elapsed. 3. A driver's door opening / closing detecting means for detecting opening / closing of a driver's door, and a current detecting means provided in a power supply circuit from the battery to a vehicle interior lamp. When the signal from the driver's door opening / closing detection unit and / or the signal from the current detection unit is input and the elapsed time after the ignition key switch is turned off exceeds the set cut waiting time, the second power supply cut unit is driven. 3. The device for preventing a battery from running out of a vehicle according to claim 1, wherein: