JPH10201091A - Power unit for vehicle using electric double layer capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the overcharge of an electric double layer capacitor caused by the dispersion of capacitance or internal resistance with every capacitor cell, and enable a long term of storage of electricity. SOLUTION: For a capacitor cell 10, balance resistors 14 for adjusting the voltage by letting discharge current flow are connected in parallel. The normally open type of relay contact 16a of a relay switch 16 is provided between the capacitor cell 10 and the balance resistor 14. Electromagnetic coils 16b are connected with one another in parallel, and are connected to a DC power source loaded on a vehicle through an accessory switch 18. When the accessory switch 18 is turned on, the capacitor cell 10 and the balance resistor 14 are connected with each other, and a discharge current flows, and the voltage adjustment is performed. When the accessory switch 18 is turned on, the connection between the capacitor cell 10 and the balance resistor 14 is broken. Hereby, the occurrence of unnecessary discharge current is prevented, and the electric energy is kept.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle power supply device using an electric double layer capacitor for supplying power to various electric loads mounted on a vehicle such as a starter motor.

[0002]

2. Description of the Related Art In an automobile engine, a lead-acid battery is generally used as a battery to drive various accessories such as a fan and a pump, or to drive a starter motor for performing cranking at the time of starting. It is installed as. This battery has a high energy density and can be used for a relatively long time.On the other hand, since it is a battery that involves a chemical reaction, it is prone to deterioration due to repeated charging and discharging, and it takes a long charging time. Have.

[0003] In recent years, various types of electric double-layer capacitors, whose capacity has been dramatically increased by utilizing an insulating film formed at the interface between an electrode and an electrolytic solution, have been used as batteries instead of the above-mentioned batteries. Proposed. Since this electric double layer capacitor generates a voltage of, for example, about 2.5 V in a single cell, when it is used as a power supply device for a vehicle, as shown in FIG.
0 are connected in series and used as a capacitor pack 102.

As shown in FIG. 5, each capacitor cell 100 has a pair of current collectors 100A having an activated carbon electrode attached thereto.
And the electrolytic solution 100B filled between the current collectors 100A
And a separator 100C for partitioning between the activated carbon electrodes of each current collector 100A to constitute an electric double layer capacitor. Each of these capacitor cells 100 is connected in series to form a capacitor pack 102, and this capacitor pack 102 is connected to a vehicle-mounted DC voltage source (abbreviated as "power supply" in the figure) mounted on the vehicle. Have been. This on-vehicle DC voltage source is configured to include, for example, a generator that generates a voltage by an engine rotational force, and a voltage converter (neither is shown) that converts the generated voltage to a predetermined DC voltage. And more specifically, an alternator.

During operation of the engine, each capacitor cell 100 is charged by the DC voltage from the DC voltage source mounted on the vehicle, and the stored energy is used for discharging the starter motor when the engine is restarted. .

Here, the electromotive force of each capacitor cell 100 is determined by the active voltage of the electrolytic solution. If the active voltage is higher than the bias voltage, that is, the charging voltage from the on-board DC voltage source, a rapid internal reaction starts. The life of the electric double layer capacitor cell 100 is reduced. For this reason, the rated voltage of the electric double layer capacitor cell 100 is set lower than the activation voltage of the electrolytic solution, and a long life which is one of the characteristics of the electric double layer capacitor is secured.

However, each of the capacitor cells 100 may vary in capacitance and internal resistance. For this reason, if charging is performed from a vehicle-mounted DC voltage source in a state where the capacitor cells 100 are connected in series, a difference occurs between the terminals of the capacitor cells 100 due to variations in capacitance and internal resistance.

That is, in order to obtain a high voltage required for driving a starter motor or the like, a plurality of capacitor cells 100 must be connected in series. Here, when each capacitor cell 100 is connected in series and charged, the value of the capacitance or the internal resistance becomes
If they are equal between 0, the voltage between both ends of each capacitor cell 100 is also equal. However, when there is a variation as described above, a difference voltage is generated. Once the difference voltage is generated, it does not disappear, but is accumulated by repeated charging and discharging, and may be expanded.

Therefore, even if the rated voltage is set in consideration of a margin, there is a possibility that the capacitor cell 100 to which a bias voltage higher than the rated voltage is applied due to the variation in the characteristics of each capacitor cell 100, The life is shortened. More specifically, the rated voltage of the capacitor pack 102, which is a series connection of the capacitor cells 100, is equal to the rated voltage of each capacitor cell 100 times the number of cells. However, even though the capacitor pack 102 has a rated voltage as a whole, some of the capacitor cells 100 may be applied with a bias voltage exceeding the rated voltage of a single cell due to a difference in internal resistance or the like. .

Therefore, in order to eliminate the difference voltage as much as possible and obtain a uniform bias voltage, as shown in FIG.
Conventionally, a “balance circuit method” has been adopted in which the bias voltage of each capacitor cell 100 is balanced by connecting the respective balance resistors 104 in parallel and connecting each of the balance resistors 104 in series.

According to this circuit, when the voltage across one capacitor cell 100 becomes higher than that of the other capacitor cells 100, the resistance value of each of the balance resistors 104 is equal. Is larger than the discharge current from the other capacitor cells 100.

Since electric charges are supplied from the constant voltage power supply to the capacitor cells 100 having a low voltage between both ends, the balance resistors 10 are finally removed from all the capacitor cells 100.
4 have the same discharge current, and each capacitor cell 1
The voltage applied between both terminals of 00 becomes equal.

Further, as another prior art, for example, in Japanese Unexamined Utility Model Publication No. Hei 5-023527, a transistor is connected in series to a balance resistor connected in parallel with a capacitor cell, and a transistor is connected to the base of the transistor. The comparator is connected. Then, the voltage between both ends of the capacitor cell and the reference voltage from the reference power supply are compared by a comparator, and when the voltage between both ends of the capacitor cell exceeds the reference voltage,
There is also disclosed a technique in which a capacitor cell and a balance resistor are connected in parallel.

[0014]

In the prior art of the balance circuit system in which the balance resistors 104 are connected in parallel to the respective capacitor cells 100 as described above, if the values of the respective balance resistors 104 are equal, the voltage dividing resistor becomes larger. Since they are equal, the bias voltage applied to each capacitor cell 100 can be equalized.

However, in the balance circuit method, since the balance resistor 104 is always connected to each capacitor cell 100 and the entire electric circuit forms a closed loop, the electric energy stored in each capacitor cell 100 is gradually lost by discharging. I will continue. Therefore, since the discharge of each capacitor cell 100 starts after the charging is stopped, a function of maintaining a long-term power storage state cannot be achieved. For example, a vehicle power supply device for driving a starter motor or the like when the engine is restarted. Is not practical.

In order to solve this problem, in the technique described in Japanese Utility Model Application Laid-Open No. Hei 5-23527, a balance resistor is connected in parallel to a capacitor cell or disconnected using a transistor or the like. According to this technology,
Unless the voltage across the capacitor cell exceeds the reference voltage, the capacitor cell and the balance resistor are not connected, so that unnecessary discharge is prevented as much as possible.

However, also in this technique, a voltage dividing resistor for detecting the voltage between both ends of the capacitor cell is connected in parallel to the capacitor cell, and these voltage dividing resistors are connected in series. Therefore, as in the prior art, a closed loop is formed as a whole, so that self-discharge of the capacitor cell cannot be prevented. Further, since it is necessary to constantly monitor the magnitude of the voltage between both ends of the capacitor cell and the reference voltage, electric energy corresponding to the monitoring is required. Therefore, when the vehicle is left unattended for a long time, the state of charge of the electric double layer capacitor may be lost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned various problems, and has as its object to provide an electric storage device capable of maintaining electric energy for a long period of time while balancing the bias voltage of an electric double layer capacitor. An object of the present invention is to provide a vehicle power supply device using a multilayer capacitor.

[0019]

According to one aspect of the present invention, there is provided a vehicle power supply apparatus using an electric double layer capacitor according to the first aspect of the present invention, wherein a main switch for controlling activation and deactivation of a voltage adjustment function by a voltage adjustment element. The operation switch means is provided. That is, a voltage adjusting element connected in parallel to each capacitor cell, and a discharge current flowing from each of the capacitor cells to each of the voltage adjusting elements is provided between each of the voltage adjusting elements and each of the capacitor cells. Switch means for controlling discharge,
An operation switch means for turning on or off each of the capacitor cells and each of the voltage adjusting elements by driving and operating each of the discharge control switch means.

When the discharge control switch means is driven by the operation switch means and the capacitor cell and the voltage adjusting element are connected via the discharge control switch means, the discharge control switch means, the capacitor cell and the voltage adjusting element are connected. An electric circuit for voltage adjustment is formed by the operation switch means.

Then, a discharge current flows from the capacitor cell having a high voltage at both ends due to variations in internal resistance and the like to the voltage adjusting element, and the voltage at both ends of each capacitor cell becomes equal. On the other hand, when the discharge control switch means is driven in reverse by the operation switch means to cut off the capacitor cell and the voltage adjusting element, the electric circuit is eliminated. This prevents self-discharge of the capacitor cells, and each capacitor cell retains the charged electric energy for a long time.

Further, as in the vehicle power supply device using the electric double layer capacitor according to the second aspect, the discharge control switch means is constituted by the normally open relay contact and the electromagnetic coil, and is operated via the operation switch means. If power is supplied to the electromagnetic coil in this manner, no electric circuit is formed when the electromagnetic coil is in a non-energized state. Therefore, self-discharge of the capacitor cell can be prevented and electric energy can be held for a long time.

Further, in the vehicle power supply device using the electric double layer capacitor according to claim 3, each of the discharge control switch means includes a transistor provided between a voltage adjusting element and a capacitor cell, and Of the bias voltage applied to the entire electric double layer capacitor and a reference voltage corresponding to the capacitor cell, and when the both-ends voltage exceeds the reference voltage, drives the transistor to drive the transistor. It comprises a voltage adjusting element and a comparator for connecting the capacitor cell, and supplies power to the comparator via operation switch means.

Thus, even if power is supplied to the comparator by the operation switch means, the transistor does not operate unless the voltage across the capacitor cell exceeds the reference voltage, and the capacitor cell and the voltage adjusting element are not connected. Therefore, discharge can be permitted only to the capacitor cell whose voltage is higher than the reference voltage and needs to be adjusted, so that the amount of current flowing through the electric circuit is reduced to reduce the consumption of electric energy and the generation of heat. be able to. On the other hand, if the power supply to the comparator is cut off by the operation switch means, an electric circuit is not formed, self-discharge from the capacitor cell is prevented, and electric energy can be held for a long time.

Further, according to the power supply device for a vehicle using the electric double layer capacitor according to the fourth aspect, a series resistor having the same value corresponding to each capacitor cell is connected in series to the electric double layer capacitor. By connecting in parallel, a voltage applied to the entire electric double layer capacitor is equally divided for each of the capacitor cells to obtain a reference voltage. Thereby, based on the bias voltage actually applied to the electric double layer capacitor, it is possible to easily obtain an appropriate reference voltage for comparing the level of the voltage between both ends of each capacitor cell.

Further, according to the power supply device for a vehicle using the electric double layer capacitor according to the fifth aspect, the operation switch means is linked to the accessory switch (ACC switch) of the vehicle. The operation switch means operates to form an electric circuit for voltage adjustment. On the other hand, when the vehicle is left for a long period of time, the electric switch is not operated, so that the electric circuit is not formed.

Therefore, during operation of the engine in which the alternator as the on-vehicle DC voltage source generates electric power, the capacitor cell and the voltage adjusting element can be connected to adjust the voltage of the capacitor cell whose voltage is too high. On the other hand, when the engine is stopped for a long period of time, the voltage adjusting element is separated from the capacitor cell to prevent self-discharge of the capacitor cell.

Thus, when there is a possibility that the voltage between both ends of the capacitor cell may be high, that is, during the period when the on-vehicle DC voltage source is generating power, an electric circuit for voltage adjustment is always formed to form the capacitor cell. Can be adjusted. Further, when there is substantially no possibility that the voltage between both ends of the capacitor cell becomes high, that is, when the vehicle is left for a long time in which the engine is stopped and the vehicle-mounted DC voltage source is not charged, the electric circuit for voltage adjustment is provided. Without forming the capacitor cell, self-discharge of the capacitor cell can be prevented, electric energy can be held, and a reduction in the life of the capacitor cell due to internal electrolysis can be prevented.

[0029]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows a circuit configuration of a vehicle electric double layer capacitor power supply device using an electric double layer capacitor according to a first embodiment of the present invention.

Each electric double layer capacitor cell 10 separates, for example, a pair of current collectors each having an activated carbon electrode on the surface, an electrolyte filled between the current collectors, and each activated carbon electrode. And a gasket (both not shown) for preventing the internal electrolyte from leaking to the outside. These capacitor cells 10 are connected in series and assembled as a capacitor pack 12 that generates a desired electromotive voltage.

The capacitor pack 12 formed by connecting the capacitor cells 10 in series as described above has the positive electrode side connected to the on-vehicle DC voltage source and the negative electrode side of the capacitor pack 12 grounded. This on-vehicle DC voltage source outputs a constant DC voltage, and specifically, includes an alternator that generates an AC voltage according to the engine speed, and a voltage converter that converts the output voltage of the alternator into a DC voltage. And a constant voltage circuit for holding a DC voltage output to the outside at a constant voltage value.

Each capacitor cell 10 has a balance resistor 1 as a "voltage adjusting element" for adjusting the voltage between both ends.
4 are connected in parallel. These balance resistors 14 are connected in series as a whole. Therefore, in other words, a series connection of the balance resistors formed by connecting the respective balance resistors 14 in series is connected in parallel to the capacitor pack 12 which is a series connection of the respective capacitor cells 10, and each of the balance resistors is connected to each other. The capacitor cells are connected to each other.

Each capacitor cell 10 and each balance resistor 1
4, a relay switch 16 is provided as "discharge control switch means". Each of these relay switches 16 includes a normally open relay contact 16 a connected between the capacitor cell 10 and the balance resistor 14.
And an electromagnetic coil 16b for closing the normally open relay contact 16a by electromagnetic force.

The electromagnetic coils 16b of each of these relay switches 16 are connected in parallel between the vehicle-mounted DC voltage source and ground. When the electromagnetic coil 16b is not energized and is not energized, the relay contact 16a is opened and the connection between the capacitor cell 10 and the balance resistor 14 is cut off. On the other hand, when the electromagnetic coil 16b is energized, the relay contact 16a is closed and the capacitor cell 10 and the balance resistor 14 are connected.

An accessory switch (ACC switch) 18 as "operation switch means" is provided between the parallel connection of the respective electromagnetic coils 16b and the vehicle-mounted DC voltage source. When the accessory switch 18 is turned on by an operation of an ignition key by a driver, power is supplied to various accessory electrical components such as a vehicle interior light. Further, even when the key is turned to the ignition position or the starter position, the on state of the accessory switch 18 is maintained. Therefore,
During the start of the engine, the accessory switch 18 is always kept on, and the electromagnetic coil 16 of each relay switch 16 is turned on.
b to close the relay contact 16a.

On the other hand, when the vehicle is left for a long period of time, the key is usually removed, so that the accessory switch 18 is turned off, the power supply to each electromagnetic coil 16b is stopped, and the relay contact 16a is opened. The accessory switch 18 controls energization and non-energization of each relay switch 16. Therefore, accessory switch 1
The arrangement position of 8 is not limited to the position shown in the figure, and may be any position at which energization (power supply) to all the relay switches 16 can be performed collectively.

Next, the operation of the present embodiment having the above configuration will be described. First, when the engine is started by turning the key, the alternator starts generating electric power, whereby each capacitor cell 10 is charged. On the other hand, the accessory switch 18 is turned on by rotating the key, the electromagnetic coil 16b of each relay switch 16 is excited, and the normally open relay contact 16a is closed. This allows
All the capacitor cells 10 are connected to the balance resistor 14 via the relay contact 16a.

Then, a discharge current flows from the capacitor cell 10 whose both ends have increased in voltage due to variations in the internal resistance or the like toward the balance resistor 14, so that the voltage of the capacitor cell 10 decreases. Further, since the alternator is a constant voltage source, electric charges are supplied to the capacitor cell 10 having a low voltage between both ends. Thereby, during the start of the engine, each capacitor cell 10 and each balance resistor 14
Are connected to form a voltage adjustment circuit, and the voltage across both ends of each capacitor cell 10 becomes equal.

Next, when the key is turned to stop the engine, the alternator stops power generation and the accessory switch 18 is turned off. Accordingly, the power supply to the electromagnetic coil 16b of each relay switch 16 is cut off, and the relay contact 16a returns to the open state. Thereby, the balance resistor 14 is disconnected from each capacitor cell 10, and the voltage adjustment circuit is eliminated. Each capacitor cell 10 holds the stored electrical energy while adjusting the voltage during engine start.

According to the present embodiment configured as described above, the following effects can be obtained. During the start of the engine, charging can be performed while adjusting the voltage between both ends of each capacitor cell 10. After the engine is stopped, the discharge current can be prevented. Therefore, electric energy can be retained for a long period of time while preventing the capacitor cell 10 from being overcharged and shortening its life, and can be prepared when the engine is restarted.

Since the accessory switch 18 is used as the "operation switch means", the accessory switch 18 is turned on and the relay switches 16 are closed during the operation of the engine so that the vehicle can be left for a long time. When the engine is stopped, the accessory switch 18 is turned off and the relay switches 16 are opened. As a result, the operation state of the engine (the power generation state of the alternator)
, The voltage of each capacitor cell 10 can be automatically adjusted.

That is, when there is a high need for adjustment such that the engine is operating and the alternator is starting to generate power, the voltage can be adjusted by connecting each of the balance resistors 14 to each of the capacitor cells 10. Is stopped and the power generation of the alternator is stopped.
Unnecessary discharge can be prevented by separating each balance resistor 14 from the above.

Further, since the relay switch 16 is composed of a normally open relay contact 16a and an electromagnetic coil 16b,
When the electromagnetic coil 16b is not energized, the capacitor cell 10
And the balance resistor 14 are not connected, and an electric circuit for voltage adjustment is not formed. Therefore, unnecessary discharge can be prevented and electric energy can be held for a long time.

That is, if a normally closed relay contact is used, the capacitor cell 10 and the balance resistor 14 are connected when the electromagnetic coil is not energized. Therefore, in order to disconnect the capacitor cell 10 and the balance resistor 14 after the engine stops, it is necessary to consume electric energy and open the normally-closed relay contact, which wastes electric energy.

Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the same components as those in the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

Also in the present embodiment, a capacitor pack 12 is formed by connecting a plurality of capacitor cells 10 in series, and a balance resistor 20 as a "voltage adjusting element" is connected to each capacitor cell 10 in parallel. ing.

Each balance resistor 20 has a transistor 2
2 are connected in series. Therefore, a resistor-transistor series body in which the balance resistor 20 and the transistor 22 are connected in series is connected in parallel to the capacitor cell 10. The transistor 22 is composed of an NPN transistor, and its base is connected to a comparator 26 via a base current limiting resistor 24.
Is connected to the output side. Therefore, each transistor 2
2 operates when the base voltage becomes “H level”, and stops operating when the base voltage becomes “L level”. The transistor 22 and the comparator 26 constitute “discharge control switch means” in the present embodiment.

Each comparator 26 compares the voltage VCS between both ends of the capacitor cell 10 with the reference voltage VA, as described later. Each comparator 26 receives the reference voltage VA on its inverting input terminal side (− side),
The non-inverting input side (+ side) receives the voltage VCS at both ends. Accordingly, each of the comparators 26 is provided with a voltage
Is higher than the reference voltage VA (VCS> VA), the output becomes “H level”, and the voltage VCS at both ends becomes the reference voltage V
In the case of A or less (VCS ≦ VA), the output is “L level”
Becomes

The capacitor pack 12 is connected in parallel with a reference voltage detecting resistor section 28 as a “resistance series body formed by connecting resistors of the same value corresponding to each capacitor cell in series”. The reference voltage detecting resistor section 28 includes a plurality of resistors 30 of the same value corresponding to the respective capacitor cells 10.
Are connected in series. Each of these resistors 30 is provided with a first resistor 30a in order to improve the voltage detection accuracy.
And the second resistor 30b.

By connecting the reference voltage detecting resistor 28 in parallel with the capacitor pack 12, the bias voltage applied to the entire capacitor pack 12, ie, the capacitor pack 1 is connected to the reference voltage detecting resistor 28.
2 is applied. Since the reference voltage detection resistor section 28 is composed of a plurality of resistors 30 corresponding to the respective capacitor cells 10, the voltage VCP across the capacitor pack 12 is equally divided by the respective resistors 30. The voltage divided by each resistor 30 is a reference voltage to be applied to each capacitor cell 10. Therefore, in order to improve the voltage detection accuracy of the voltage divided by the resistor 30, each of the resistors 30a, 30
The voltage is divided by b to obtain a reference voltage VA. The reference voltage VA is input to the inverting input terminal of the comparator 26.

On the other hand, each capacitor cell 10 is connected in parallel with a cell voltage detecting resistor 32 for detecting the voltage across the capacitor cell 10. Also,
Each of the cell voltage detecting resistors 32 includes a first resistor 32a and a second resistor 32a.
And has the same configuration as the resistor 30. That is, the resistor 32a and the resistor 3
0a, the resistor 32b and the resistor 30b are equal to each other.
The voltage between both ends of the capacitor cell 10 detected by each of the cell voltage detecting resistors 32 is equal to each of the resistors 32a, 32
2b as a voltage VCS between both ends of the cell,
6 is input to the non-inverting input terminal side.

The comparators 26 are connected in parallel with each other, similarly to the electromagnetic coil 16b of the relay switch 16 described in the first embodiment, and the comparator parallel connection is connected in parallel to the capacitor pack 12. .
An accessory switch 18 as an "operation switch means" is provided between the comparator parallel connection part and the vehicle-mounted DC voltage source.

Next, the operation of the present embodiment having the above configuration will be described. First, when the engine is started by turning the key, the alternator, which is an on-vehicle DC voltage source, starts generating power to charge each of the capacitor cells 10, and turns on the accessory switch 18 to turn on each of the comparators 26. Activated.

Then, each comparator 26 compares the reference voltage VA with the voltage VCS between both ends of the capacitor cell 10. When the voltage VCS across the cell is higher than the reference voltage VA, the output of the comparator 26 becomes “H level”, and the transistor 22 operates to activate the capacitor cell 10.
And the balance resistor 20 are connected. As a result, a discharge current flows from the capacitor cell 10 having a higher cell-end voltage VCS than the reference voltage VA to the balance resistor 20,
The voltage VCS between both ends of the capacitor cell 10 decreases.

On the other hand, the voltage VCS across the cell is equal to the reference voltage VA.
In the following cases, the output of the comparator 26 becomes “L level”, the transistor 22 stops, and the capacitor cell 10
And the balance resistor 20 are separated. As a result, no discharge current flows from the capacitor cell 10 in which the cell end-to-end voltage VCS is lower than the reference voltage VA, and electric energy is retained.

Next, when the engine is stopped by turning the key and the vehicle is left for a long period of time, the accessory switch 18 is turned off and the power supply to each comparator 26 is cut off. As a result, the output of the comparator 26 becomes “L level”, the transistor 22 stops, and the capacitor cell 10 and the balance resistor 20 are disconnected.
When the accessory switch 18 is turned off, the reference voltage detection resistor 28 is disconnected from the capacitor pack 12. Accordingly, the discharge of each capacitor cell 10 is prevented, and no current flows through the reference voltage detection resistor section 28.

Also in this embodiment, the accessory switch 1
Since the voltage adjustment of the capacitor cell 10 is permitted only when the switch 8 is in the ON state, the voltage adjustment of each capacitor cell 10 is performed during the operation of the engine and the overcharging is performed as in the first embodiment. The service life can be prevented from being shortened, and after the engine is stopped, discharge from each capacitor cell 10 can be prevented, and electric energy can be held for a long time. In addition to this, the present embodiment further exerts the following effects.

The transistor 22 provided for each capacitor cell 10 and the voltage VC across the capacitor cell 10
When S exceeds the reference voltage VA, the transistor 2
2 to turn on the balance resistor 20 and connect each of the comparators 26 to connect the capacitor cell 10 to constitute a "discharge control switch means" to supply power to each of the comparators 26 via the accessory switch 18. Therefore, the voltage adjustment can be performed by connecting the balance resistor 20 only to the capacitor cell 10 requiring the voltage adjustment.

That is, in this embodiment, even if the accessory switch 18 is closed and power is supplied to the comparator 26, the transistor 22 does not operate unless the voltage VCS across the capacitor cell 10 exceeds the reference voltage VA.
Therefore, the capacitor cell 10 and the balance resistor 20 are not connected. Thereby, the both-ends voltage VCS becomes the reference voltage
Discharge can be permitted only to the capacitor cells 10 that are higher than A and require voltage adjustment. As a result, the amount of electric energy consumed and the amount of heat generated can be reduced by reducing the amount of current flowing through the electric circuit.

The capacitor pack 12 is connected in parallel to the capacitor pack 12 by connecting a reference voltage detecting resistor section 28 as a "resistor series body" in which resistors 30 of the same value corresponding to the respective capacitor cells 10 are connected in series.
2 is equally divided for each capacitor cell 10 to obtain the reference voltage VA. Therefore, the reference for determining whether the voltage VCS between both ends of each capacitor cell 10 is appropriate or not is obtained. Voltage VA can be easily obtained.

For example, a battery or a battery cell having an output voltage equal to the reference voltage VA is prepared as a reference power source.
A configuration for comparing these separate reference power supplies with the cell end-to-end voltage VCS is also possible. However, when a separate reference power source is used, the manufacturing cost increases accordingly.

It should be noted that the present invention is not limited to the configuration of each of the above embodiments, and various modifications can be made within the scope of the invention. For example, the case where a resistor is used as the “voltage adjusting element” has been described as an example. However, the present invention is not limited to this, and as in a modification shown in FIG.
May be used. In this case, the Zener voltage VZ of the Zener diode 40 is
, The cell end-to-end voltage VCS is higher (V.sub.V) as in the second embodiment.
CS> VZ) Only the capacitor cell 10 can perform voltage adjustment. Further, when the accessory switch 18 is turned off, the Zener diode 40 is disconnected from the power supply, so that a minute dark current can be prevented from flowing.

Further, in each of the above embodiments, the case where the accessory switch 18 itself is used as the “operation switch means” has been described as an example, but other relay switches interlocked with the operation of the accessory switch 18 may be used. It may be separately used as "operation switch means". Furthermore,
If the accessory switch 18 is used as the "operation switch means", the voltage of the capacitor cell 10 can be automatically adjusted according to the start of the engine as described above. In addition, for example, a manually operated push button A switch may be provided in the passenger compartment to enable manual operation when the engine is stopped. Further, instead of the accessory switch 18, another switch that reflects the start / stop state of the engine, such as an ignition switch, may be used.

[0064]

As described above, according to the vehicle power supply device using the electric double layer capacitor according to the present invention, the discharge control switch means can be driven and operated via the operation switch means. Therefore, by adjusting the voltage between both ends of each capacitor cell, overcharge can be prevented, and the life can be prevented from being shortened. In addition, unnecessary discharge can be prevented, a long-term power storage state can be secured, and the engine is prepared for restart. be able to.

[Brief description of the drawings]

FIG. 1 is a schematic circuit configuration diagram of a vehicle power supply device using an electric double layer capacitor according to a first embodiment of the present invention.

FIG. 2 is a schematic circuit configuration diagram of a vehicle power supply device using an electric double layer capacitor according to a second embodiment of the present invention.

FIG. 3 is a schematic circuit configuration diagram of a modified example of the vehicle power supply device using the electric double layer capacitor according to the present invention.

FIG. 4 is a schematic circuit configuration diagram showing a main part of a vehicle power supply device using an electric double layer capacitor according to a conventional technique.

FIG. 5 is an explanatory diagram showing a general configuration of an electric double layer capacitor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Capacitor cell 12 Capacitor pack 14 Balance resistor 16 Relay switch 18 Accessory switch 20 Balance resistor 22 Transistor 26 Comparator 28 Reference voltage detection resistance part 30 Resistance

Claims (5)

[Claims] 1. A vehicle power supply device using an electric double layer capacitor formed by connecting a plurality of capacitor cells in series, comprising: a voltage adjusting element connected in parallel to each of the capacitor cells; A discharge control switch means provided between each capacitor cell and controlling a discharge current flowing from each of the capacitor cells to each of the voltage adjusting elements; and A power supply device for a vehicle using an electric double-layer capacitor, comprising: an operation switch means for setting a capacitor cell and each of the voltage adjusting elements to a conductive state or a cut-off state. 2. The discharge control switch means comprises a normally open relay contact provided between the voltage adjusting element and the capacitor cell, and an electromagnetic coil for driving the normally open relay contact. The power supply device for a vehicle using an electric double layer capacitor according to claim 1, wherein power is supplied to the electromagnetic coil via the operation switch means. 3. The discharge control switch means includes: a transistor provided between the voltage adjusting element and the capacitor cell; a voltage across the capacitor cell; and a voltage applied to the entire electric double layer capacitor. A bias voltage is compared with a reference voltage corresponding to the capacitor cell, and a comparator that connects the voltage adjustment element and the capacitor cell by driving the transistor when the both-ends voltage exceeds the reference voltage. The power supply device for a vehicle using an electric double-layer capacitor according to claim 1, wherein the power supply is configured to supply an operating current to the comparator via the operation switch means. 4. The entirety of the electric double layer capacitor is connected to the electric double layer capacitor by connecting in parallel a resistance series body formed by serially connecting resistors having the same value corresponding to the respective capacitor cells in series. The power supply device for a vehicle using an electric double layer capacitor according to claim 3, wherein the voltage applied to the capacitor is obtained by equally dividing the voltage applied to each of the capacitor cells. 5. The power supply device for a vehicle using an electric double layer capacitor according to claim 1, wherein the operation switch means is linked with an accessory switch of the vehicle.