JP2002125303A - Power supply for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply for a vehicle, capable of controlling an output voltage within a voltage range in which an electric motor will not become inefficient, even if there is voltage drop in each capacitor cell due to discharging of the capacitors. SOLUTION: In a power supply used for a vehicle that drives the electric motor 6 to travel using electric power accumulated in an electricity-storing device 4, the electricity-storing device is structured with at least three divided groups of capacitors, 41, 42, 43, each having a plurality of electric double-layer capacitor cells. The device also comprises a voltage-detecting means 40, that detects the voltage of the electricity-storing device and change-over means 401, 402, 403 that change over the connection of the first and second capacitors based on the detection result of the voltage-detecting means. The change-over means connects the first group of capacitors parallel to the second group of them in a normal state, and connects them in series connection, when the voltage drop of the electricity-storing device is detected by the voltage-detecting means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle using a power storage device as a power source or a hybrid vehicle using a power storage device and an engine generator as power sources, and particularly to an electric vehicle suitable for use in these commercial vehicles. Power supply device.

[0002]

2. Description of the Related Art An electric vehicle such as a hybrid vehicle repeatedly discharges when the vehicle is accelerating and recharges when braking, and the number of repetitions reaches tens of thousands of times. Must withstand the number of cycles. Therefore, it has been proposed to apply an electric double layer capacitor to such an electric vehicle that has a longer charge / discharge cycle life than a chemical battery and has high energy use efficiency during high-output operation.

In particular, commercial vehicles such as trucks have a heavy vehicle weight and require a large power source to drive the vehicle. Therefore, a large current can be taken out at one time, and electric power obtained by converting kinetic energy during braking can be obtained. Is an electric double layer capacitor that can efficiently accumulate electricity and is most suitable for commercial vehicles.

FIG. 5 shows a configuration of a conventional power supply device of a hybrid vehicle using the electric double layer capacitor.

In FIG. 5, reference numeral 3 denotes a converter, which is supplied with power from a generator connected to the engine.
Reference numeral 4 denotes a main power storage device, 5 denotes an inverter that drives a vehicle drive motor 6, 7 denotes a DC-DC converter that charges an auxiliary power storage device 8, and 9 denotes an auxiliary machine that is supplied with power by the auxiliary power storage device 8. The main power storage device 4 is configured by connecting a plurality of electric double layer capacitor cells 431a, 431b, 431c,... In series. The illustration of the drive mechanism after the vehicle drive motor 6 is omitted.

[0006]

In the conventional power supply device for an electric vehicle, the output voltage of the power storage device decreases with the discharge of the capacitor, so that the efficiency of the motor to which the reduced voltage is supplied decreases, and the power storage device There is a problem that the use efficiency of the charged energy is deteriorated.

For this reason, a voltage stabilizing circuit (current pump) using a switching converter is connected to the output of the power storage device so that the output voltage of the power storage device is not changed even if the voltage of the capacitor cell decreases due to discharge. It has been proposed to boost the output voltage of a power storage device and supply a constant voltage to a motor. However, if a voltage stabilization circuit using such a switching converter is used in a commercial vehicle that requires a large driving force, a choke coil with a large current is required, so the mass is extremely large, several hundred kilograms, and the weight can be reduced. It is not suitable for the required power supply for electric vehicles. In addition, since it is necessary to use a switching element having a large current, the cost of the voltage stabilizing circuit increases.

On the other hand, it has been proposed to suppress the voltage drop by connecting all of the two capacitor cells connected in parallel in series with the discharge of the capacitor. When the connection is switched, the output voltage of the power storage device sharply rises, exceeds the usable voltage of the motor, or operates in a region where the efficiency of the motor is poor.

According to the present invention, an electric double layer capacitor cell is divided into a plurality of capacitor groups and arranged, and two cell groups normally connected in parallel are connected in series.
Even if the voltage of each capacitor cell drops due to discharge of the capacitor, while preventing the output voltage of the entire power storage device from decreasing,
It is an object of the present invention to provide an electric vehicle power supply device capable of controlling an output voltage in a voltage region where the efficiency of the electric motor does not deteriorate.

[0010]

According to a first aspect of the present invention, there is provided a power supply device used for a vehicle that travels by driving an electric motor with electric power stored in a power storage device, wherein each of the power storage devices includes a plurality of electric double layer capacitors. At least three with cells
And a third capacitor group is connected in series with the first capacitor group and the second capacitor group, and detects a voltage of the power storage device. Voltage detecting means, and switching means for switching a connection between the first capacitor and the second capacitor based on a detection result of the voltage detecting means, wherein the switching means is configured to switch the connection between the first capacitor and the second capacitor in a normal state. The first capacitor group and the second capacitor group are connected in parallel, and when the voltage detecting means detects that the voltage of the power storage device has dropped, the first capacitor and the second capacitor are connected in series. Connect to

[0011] In a second aspect based on the first aspect, the power storage device includes a positive electrode of the first capacitor group and a second electrode.
The positive electrode of the capacitor group is connected via a first switch, the positive electrode of the first capacitor group and the negative electrode of the second capacitor group are connected via a second switch,
The negative electrode of the first capacitor group and the negative electrode of the second capacitor group are connected via a third switch, and in a normal state, the switching unit includes the first switch and the third switch in a normal state. And the second switch are opened in a closed state and the second switch is opened, thereby connecting the first capacitor group and the second capacitor group in parallel. When detecting that the voltage has dropped, the second switch is closed, and the first switch and the third switch are opened, whereby the first capacitor group and the second switch are closed. The capacitor group is connected in series.

In a third aspect based on the second aspect, the negative electrode of the first capacitor group is connected to the positive electrode of the third capacitor group, and the positive electrode of the second capacitor group is connected to the positive electrode of the second capacitor group. An external connection electrode of the power storage device is drawn from a negative electrode of the third capacitor group.

In a fourth aspect based on the second aspect, the second switch is switched to a closed state after the first switch and the third switch are opened, and the second switch is switched to a closed state. The first switch and the third switch are switched to a closed state after the first switch is opened.

In a fifth aspect based on the first to fourth aspects, the switching means includes an output voltage of the power storage device when the first capacitor group and the second capacitor group are connected in series. However, switching control is performed at a voltage that does not exceed an output voltage of the power storage device in a fully charged state when the first capacitor group and the second capacitor group are connected in parallel.

According to a sixth aspect, in the first to fifth aspects, the first capacitor group and the second capacitor group are connected in parallel when the power storage device is in a charged state. Features.

In a seventh aspect based on the first to sixth aspects, the electric double layer capacitor cell constituting the power storage device includes overcharge preventing means for detecting a voltage of the capacitor cell, The charging prevention means outputs a full charge signal by bypassing the charging current when the voltage of the capacitor cell reaches a predetermined voltage.

According to an eighth aspect of the present invention, there is provided a power supply device used for a commercial vehicle that travels by driving an electric motor with electric power stored in a power storage device, wherein each of the power storage devices includes a plurality of electric double layer capacitor cells. The capacitor cell is provided with overcharge prevention means for detecting the voltage of the capacitor cell, and the overcharge prevention means reduces the charging current when the voltage of the capacitor cell reaches a predetermined voltage. Bypass and output full charge signal.

[0018]

According to the first aspect of the present invention, in the normal state, the first capacitor group and the second capacitor group are connected in parallel, and the voltage detecting means detects that the voltage of the power storage device has dropped. Since the first capacitor and the second capacitor are connected in series, the power stored in the capacitor can be used without wasting, and the power stored in the capacitor can be used in a voltage region where the electric motor can efficiently use the power. The output voltage of the power storage device can be controlled.

According to the second invention, in the power storage device, the positive electrode of the first capacitor group and the positive electrode of the second capacitor group are connected via the first switch, and the positive electrode of the first capacitor group and the second electrode are connected to each other. And a negative electrode of the first capacitor group and a negative electrode of the second capacitor group are connected via a third switch. In a normal state, By setting the first switch and the third switch to a closed state and the second switch to an open state, the first capacitor group and the second capacitor group are connected in parallel. When detecting that the voltage of the power storage device has dropped, the first switch and the third capacitor are connected by closing the second switch and opening the first switch and the third switch. Because they are connected in series, Together can be used without wasting the electric power accumulated in capacitor, the power stored in the capacitor motor capable of controlling the output voltage of the efficient power storage device to the voltage space available.

In the third invention, since the third capacitor group is provided in series with the first capacitor group and the second capacitor group that can be switched between series / parallel connection, the connection state of the capacitor group is changed from parallel connection. By controlling the voltage that rises when switching to series connection, the output voltage of the power storage device can be controlled to a voltage region where the electric power stored in the capacitor can be used efficiently by the motor.

In the fourth invention, the first switch and the third switch
After the switch is opened, the second switch is switched to the closed state, and after the second switch is opened, the first switch and the third switch are switched to the closed state. There is no short circuit between the first capacitor group and the second capacitor group.

According to the fifth aspect, when the first capacitor group and the second capacitor group are connected in series, the output voltage of the power storage device increases the first capacitor group and the second capacitor group in parallel. Since the switching means is controlled so as not to exceed the output voltage in the fully charged state of the power storage device when connected,
The output voltage of the power storage device can be controlled in a voltage region where the electric power stored in the capacitor can be used efficiently by the electric motor.

According to the sixth aspect, in the charging state, the first capacitor group and the second capacitor group are connected in parallel, so that the power storage device is charged without converting the power generated by the generator into a high voltage. As a result, energy loss during charging of the power storage device can be reduced.

In the seventh or eighth invention, the overcharging prevention means for bypassing the charging current when the voltage of the capacitor cell reaches the predetermined voltage is connected in parallel to the capacitor cell, so that the capacitor cell at the time of completion of charging is completed. Since the discharge is started with the amount of electricity aligned, no load is imposed on a specific capacitor cell.

[0025]

Next, a first embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a power supply device for a series hybrid electric vehicle according to an embodiment of the present invention.

The engine 1 is a prime mover such as a gasoline engine, a diesel engine, a CNG engine, and the like. Generator 2
Is rotated by the engine 1 to charge the main power storage device 4,
The electric power for rotating the vehicle drive motor 6 is generated. Converter 3 is provided between generator 2 and main power storage device 4. Converter 3 converts the power generated by generator 2 into a voltage and a current suitable for charging main power storage device 4. An inverter 5 is provided between the converter 3 and the vehicle drive motor 6. The inverter 5 converts the power generated by the generator 2 and converted by the converter 3 and the power stored in the main power storage device 4 into a voltage and a current suitable for driving the vehicle drive motor 6, and converts the power and the power into the vehicle drive motor 6. Supply.

That is, part or all of the electric power generated by the generator 2 is supplied to the main power storage device 4, which charges the main power storage device 4. Then, the vehicle is driven by the vehicle drive motor 6 using the power generated by the generator 2 and the power stored in the main power storage device 4. More specifically, during acceleration, the electric power of both the generator 2 and the main power storage device 4 or the main power storage device 4
The vehicle drive motor 6 is driven only by the electric power of. Further, at the time of regenerative braking, the braking power generated by the vehicle drive motor 6 is regenerated to the main power storage device 4 via the inverter 5 and charged.

In FIG. 1, the drive mechanism after the vehicle drive motor 6 is not shown.

A voltage monitoring circuit 40 is provided at both ends of the main power storage device 4.
Is provided. The voltage monitoring circuit 40 monitors the voltage across the main power storage device 4, and drives the switches 401, 402, and 403 according to the monitoring result. Specifically, when the discharge of the capacitor cells progresses and the voltage between the terminals of each capacitor cell decreases, the voltage monitoring circuit 40 detects that the output voltage of the main power storage device 4 has decreased, and outputs a switch switching signal. And switches 401, 402,
403. This switch switching signal switches the opening and closing of switches 401, 402, and 403, and the number of capacitors connected in series, that is, the output voltage of main power storage device 4 changes.

The power supply according to the present embodiment includes an auxiliary power storage device 8. This auxiliary power storage device 8 is a DC-DC
Charged by converter 7 and stores electric power for driving accessory 9.

The main power storage device 4 for storing the electric power generated by the generator 2 and supplying the stored electric power to the vehicle drive motor 6 includes electric double-layer capacitor cells 411a, 421a, 431a and the like connected in series and in parallel. It is configured. These electric double layer capacitor cells are divided into three capacitor groups 41, 42, 43, and each capacitor group is configured by connecting electric double layer capacitor cells in series and in parallel. Further, a switch 401, a capacitor 401 and a capacitor 42 are provided between the capacitor group 41 and the capacitor group 42.
402 and 403 are provided, and the capacitors 41 and 42 are connected in series or connected in parallel by these switches.

The capacitor group 43 is configured such that the negative electrode (negative terminal) of the capacitor group 41 and the positive electrode (positive terminal) of the capacitor group 43 are connected to the capacitor groups 41 and 42 whose connection form can be changed in series or in parallel. Connected to be.

The switches 401, 402, 403
The switch 401 is configured by a semiconductor switching element, and is connected so as to interrupt the current path between the positive electrode (plus terminal) of the capacitor group 41 and the positive electrode (plus terminal) of the capacitor group 42. Positive terminal (plus terminal) of capacitor group 41 and capacitor group 4
The switch 403 is connected so as to interrupt the current path between the negative electrode (negative terminal) of the capacitor group 41 and the negative electrode (negative terminal) of the capacitor group 42. They are connected so as to interrupt the route.

The switches 401, 402, 403
The switch is opened and closed according to the detection result of the voltage of the main power storage device 4 by the voltage monitoring circuit 40. Specifically, the voltage monitoring circuit 40 detects that the output voltage of the main power storage device 4 is in a normal state, and the switches 401 and 403
Is closed and the switch 402 is open,
As shown in FIG. 1, a capacitor group 41 and a capacitor group 42
And are connected in parallel. The voltage monitoring circuit 40 detects that the output voltage of the main power storage device 4 has dropped, and when the switches 401 and 403 are open and the switch 402 is closed, the detailed configuration of the main power storage device 4 is changed. As shown in the block diagram shown in FIG. 2, a capacitor group 41 and a capacitor group 42 are connected in series.

Therefore, when the capacitor group 41 and the capacitor group 42 are connected in parallel, a voltage obtained by adding the voltage of the capacitor group 43 to the voltage of the capacitor group 41 and the capacitor group 42 connected in parallel is mainly used. Output from power storage device 4. On the other hand, capacitor group 41 and capacitor group 4
2 are connected in series, the capacitor group 4
1 and the voltage of the capacitor group 42 and the capacitor group 43
Then, a voltage obtained by adding the above voltage is output from main power storage device 4.

The switches 401, 402 and 403 are switched so that the capacitor groups 41 and 42 are not short-circuited. That is, when switching the capacitor groups 41 and 42 from parallel connection to series connection, the switch 402 is closed after the switches 401 and 403 are opened. On the other hand, when switching the capacitor groups 41 and 42 from series connection to parallel connection, the switch 401 and the switch 403 are closed after the switch 402 is opened.

The switches 401, 402, 403
When charging main power storage device 4, capacitor group 4
1, 42 are switched to the parallel state. That is, when the vehicle is in regenerative braking, the switch 401 and the switch 403 are closed, and the switch 402 is opened, and the regenerative electric power generated by the vehicle drive motor 6 is regenerated and charged in the main power storage device 4.

FIG. 2 is a block diagram showing a detailed configuration of main power storage device 4 of the power supply device according to the embodiment of the present invention. FIG. 2 shows a state in which a capacitor group 41 and a capacitor group 42 are connected in series, unlike FIG.

Each of the capacitor groups 41 and 42 is formed by connecting 15 sets of 15 electric double layer capacitor cells in series and connecting them in parallel. On the other hand, the capacitor group 43
Is configured by connecting two sets of 25 electric double layer capacitor cells connected in series, connecting them in parallel, further connecting 5 sets in series, and then connecting 3 sets in parallel. That is, in the capacitor groups 41 and 42, 15 capacitor cells are connected in the series direction, and 45 capacitor cells are used respectively. On the other hand, the capacitor group 43
Are connected in series with 250 capacitor cells, and are composed of 750 capacitor cells.

Therefore, the switches 401, 402, 403
Accordingly, when capacitor groups 41 and 42 are connected in parallel, main power storage device 4 outputs a voltage in which 265 capacitor cells are connected in series, and capacitor groups 41 and 42
Are connected in series, the main power storage device outputs a voltage in which 280 capacitor cells are connected in series.

Each of the capacitor cells 411a, 41
1b, 411c, etc. have overcharge prevention circuits 412, respectively.
a, 412b, 412c, etc. are connected in parallel. The overcharge prevention circuit 412a and the like define the full charge voltage of each capacitor cell. When each capacitor cell reaches the full charge voltage, the charge current is bypassed to the overcharge prevention circuit 412a and the like, and each capacitor cell is charged. Control is performed so that the voltage does not rise too much. This is because characteristics such as capacitance of each capacitor cell vary due to manufacturing variation of each capacitor cell, variation of leakage current, aging, temperature condition and the like. If the electrostatic capacity varies and the discharge is started with the charged amount being varied, the amplitude of the voltage change in the charge / discharge cycle differs depending on the capacitor cell, and a load is imposed on the capacitor cell where the amplitude increases. , Because it will deteriorate early,
That is, it is to match the characteristics between the capacitor cells in the initial state of the discharge.

FIG. 3 is a circuit diagram showing an example of a configuration using a Zener diode, such as the capacitor cell overcharge prevention circuit 412a of the embodiment of the present invention. A zener diode (ZD) is connected to the capacitor cell 411a, and when the voltage of the capacitor cell exceeds the zener voltage, a current (Ic) for charging the capacitor cell bypasses the capacitor cell 411a and passes through the zener diode (ZD).
Since the current flows to D) (Ib) and does not flow to the capacitor cell 411a, the voltage of the capacitor cell 411a does not exceed the Zener voltage.

Further, the bypassed charging current (I
b), the Zener diode (Z
A photocoupler (D) is arranged in series with D). The photocoupler (D) detects that the capacitor cell has reached the full charge voltage, outputs a full charge detection signal, and can control charging and discharging.

FIG. 4 is a diagram showing a discharge state of the electric double layer capacitor cell according to the embodiment of the present invention, that is, a change in voltage of main power storage device 4 with time.

In the initial discharge state (full charge state), the output voltage of main power storage device 4 starts discharging from V1, and the voltage gradually decreases. When the output voltage of the main power storage device 4 becomes the serial / parallel switching voltage (V0), the voltage monitoring circuit 40 detects this and switches the switches 401, 402, and 403,
The capacitor groups 41 and 42 are switched from parallel connection in normal operation to series connection. As a result, the output voltage of main power storage device 4 approaches the output voltage (V1) in the fully charged state, and discharge is started again from this voltage. Thus, the vehicle drive motor 6
The power charged in the capacitor can be used efficiently without reducing the efficiency of the capacitor.

This series-parallel switching voltage (V0) is determined in consideration of the permissible voltage at which the efficiency of the vehicle drive motor 6 is maintained within a certain range. The difference (V1−V0) between the full charge voltage and the series-parallel switching voltage is caused by the difference in the number of capacitor cells in which the number connected in series increases due to the switching of the capacitor group from parallel to series. In the present embodiment, the number of capacitor cells connected in series is 265 in a parallel state and 280 in a series state. Also, 1
Since the control voltage when the cell is fully charged is 2.7 V, the output voltage of main power storage device 4 in the initial charging state is approximately 715 V. The permissible performance voltage of vehicle drive motor 6 used in the present embodiment is rated. Since the voltage is 95% of the voltage, the series / parallel switching voltage (V0) may be set to about 680V. At this time, the number of capacitor cells connected in series must be determined so that even if the capacitor cells are connected in series, the maximum output voltage (V1) of main power storage device 4 does not exceed 715 V.

Since the output voltage of the capacitor cell at the time of the series-parallel switching voltage (V0) is 2.57 V, it is convenient to connect approximately 280 capacitor cells in series during series connection.

The above-described embodiment of the present invention relates to an engine,
Although the power supply device according to the present invention is applied to a hybrid electric vehicle equipped with a generator, the present invention can also be applied to a power supply device of an electric vehicle not equipped with a generator. In this case, without providing the engine 1 and the generator 2,
The main power storage device 4 may be charged from a fixedly provided power supply via the converter 3.

As described above, in the embodiment of the present invention, the main power storage device is composed of a first capacitor group 41 provided with a plurality of electric double layer capacitor cells and a second capacitor group 4
2 and a third capacitor group 43, and the positive electrode of the first capacitor group 41 and the positive electrode of the second capacitor group 42 are connected via the first switch 401. The positive electrode 41 and the negative electrode of the second capacitor group 42 are connected via a second switch 402, and the negative electrode of the first capacitor group and the negative electrode of the second capacitor group are connected via a third switch 403. Connect to the first capacitor group 4
1 is connected to the positive electrode of the third capacitor group 43,
Positive electrode of second capacitor group 42 and third capacitor group 4
The output of the main power storage device 4 can be taken out from the negative electrode of the power storage device 3.
And the third switch 403 are closed and the second switch 402 is opened.
When the first capacitor group 41 and the second capacitor group 42 are connected in parallel, and the voltage monitoring circuit 40 detects that the voltage of the main power storage device 4 has dropped, the second switch 402 is closed and the second switch 402 is closed. The first switch 401 and the third switch 40
3 and the first capacitor group 4
Since the first and second capacitor groups 42 are connected in series,
The power stored in the capacitor can be used without wasting, and the output voltage of the power storage device can be controlled to a voltage region where the electric power stored in the capacitor can be used efficiently by the electric motor. Further, the output voltage of the main power storage device 4 is suppressed to a voltage range in which the vehicle drive motor 6 can efficiently use the electric power stored in the capacitors, by suppressing a voltage increase when changing the capacitor groups 41 and 42 from parallel connection to series connection. Can be controlled.

The switches 401, 402, 403
Are a first capacitor group 41 and a second capacitor group 42
Is switched from parallel connection to series connection, after the switches 401 and 403 are opened, the switch 402 is closed and the capacitor groups 41 and 42 are closed.
When switching from the serial connection to the parallel connection, the switch 401 and the switch 403 are switched to be in the closed state after the switch 402 is in the open state. Therefore, the first capacitor group 41 and the second capacitor It is possible to prevent a sudden discharge of the capacitor group without short-circuiting the group, prevent the capacitor cell from being damaged, and also prevent the peripheral circuit from being damaged by a temporary large current.

The switches 401, 402, 403
When the main power storage device 4 is charged, the switch 401
And the switch 403 are closed and the switch 402 is open, and the first capacitor group 41 and the second capacitor group 42 are switched to the parallel state. Therefore, the power generated by the generator 2 is converted by the converter 3. Since the main power storage device 4 can be charged with the voltage suppressed, the energy loss at the time of charging the main power storage device 4 can be reduced, and the energy efficiency can be increased.

The main power storage device 4 when the first capacitor group 41 and the second capacitor group 42 are connected in series
Output voltage of main power storage device 4 (first capacitor group 4
The switch 40 has a voltage that does not exceed the output voltage in the fully charged state (in a state where the first and second capacitor groups 42 are connected in parallel).
Since 1, 402, and 403 are switched, the output voltage of the power storage device can be controlled to a voltage region where the electric power stored in the capacitor can be used efficiently by the electric motor.

Further, since the voltage monitoring circuit that bypasses the charging current when the voltage of the capacitor cell reaches a predetermined voltage is connected in parallel with the capacitor cell, the amount of electricity to be charged becomes uneven due to the variation in capacitance. Since the discharge is started by adjusting the amount of electricity at the time of completion of charging of the capacitor cell, the amplitude of the voltage change in the charge / discharge cycle by the capacitor cell can be uniformed, and the load on a specific capacitor cell can be reduced. It is possible to prevent early deterioration of the capacitor cell without being applied.

[Brief description of the drawings]

FIG. 1 is a block diagram of a power supply device of a hybrid electric vehicle according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a configuration of a capacitor cell of the power supply device according to the embodiment of the present invention.

FIG. 3 is a circuit diagram showing a configuration of a capacitor cell voltage monitoring circuit according to an embodiment of the present invention.

FIG. 4 is a diagram showing a discharge state of the capacitor cell according to the embodiment of the present invention.

FIG. 5 is a block diagram of a power supply device of a conventional series-type hybrid electric vehicle.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 engine 2 generator 3 converter 4 main power storage device 5 inverter 6 vehicle drive motor 7 DC-DC converter 8 auxiliary power storage device 9 auxiliary device 40 voltage monitoring circuit 41, 42, 43 capacitor group 411a, 411b, 411c electric double layer capacitor cell 421a, 421b, 421c Electric double layer capacitor cell 431a, 431b Electric double layer capacitor cell 412a, 412b, 412c Capacitor cell overcharge prevention circuit 422a, 422b, 422c Capacitor cell overcharge prevention circuit 432a, 432b Capacitor cell overcharge prevention circuit 401 , 402, 403 switch

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ikuo Nozu Saitama Prefecture, Ooichi, Daiichi Ichibanchi, Nissan Diesel Kogyo Co., Ltd. F term in the company (reference) 5H007 BB06 CC01 DA06 5H115 PA08 PA11 PG04 PI14 PU26 PV09 QE18 SE06 TI05 TR19 TU04

Claims (8)

[Claims] 1. A power supply device used for a vehicle that runs by driving an electric motor with electric power stored in a power storage device, wherein the power storage device is divided into at least three capacitor groups each including a plurality of electric double layer capacitor cells. A third capacitor group of the capacitor group is configured to be connected in series to the first capacitor group and the second capacitor group, and a voltage detection unit configured to detect a voltage of the power storage device; Switching means for switching a connection between the first capacitor and the second capacitor based on a detection result of the voltage detection means, wherein the switching means is configured to switch between the first capacitor group and the first capacitor group in a normal state. The second capacitor group is connected in parallel, and when the voltage detecting means detects that the voltage of the power storage device has dropped, the first capacitor and the second capacitor group are connected. A power supply device for a vehicle, wherein the power supply device and the second capacitor are connected in series. 2. The power storage device, wherein a positive electrode of the first capacitor group and a positive electrode of the second capacitor group are connected via a first switch, and a positive electrode of the first capacitor group and the positive electrode of the first capacitor group are connected to each other. And a negative electrode of the second capacitor group is connected via a second switch, and a negative electrode of the first capacitor group and a negative electrode of the second capacitor group are connected via a third switch; In a normal state, the switching unit closes the first switch and the third switch, and opens the second switch, so that the first capacitor group and the second capacitor are closed. A capacitor group is connected in parallel, and when the voltage detecting means detects that the voltage of the power storage device has decreased, the second switch is closed, and the first switch and the third switch are connected. To open Ri,
The vehicle power supply device according to claim 1, wherein the first capacitor group and the second capacitor group are connected in series. 3. The negative electrode of the first capacitor group and the positive electrode of the third capacitor group are connected, and the positive electrode of the second capacitor group and the negative electrode of the third capacitor group The vehicle power supply device according to claim 2, wherein an external connection electrode of the power storage device is drawn out. 4. After the first switch and the third switch are opened, the second switch is switched to a closed state, and after the second switch is opened, the second switch is closed. The vehicle power supply device according to claim 2, wherein the first switch and the third switch are switched to a closed state. 5. The switching unit according to claim 1, wherein the output voltage of the power storage device when the first capacitor group and the second capacitor group are connected in series is equal to the first capacitor group and the second capacitor group. The vehicle power supply according to any one of claims 1 to 4, wherein switching control is performed at a voltage that does not exceed an output voltage of the power storage device in a fully charged state when a capacitor group is connected in parallel. apparatus. 6. The device according to claim 1, wherein when the power storage device is in a charged state, the first capacitor group and the second capacitor group are connected in parallel. The power supply device for a vehicle according to any one of the above. 7. The electric double layer capacitor cell constituting the power storage device includes an overcharge prevention unit that detects a voltage of the capacitor cell, wherein the overcharge prevention unit determines that the voltage of the capacitor cell is a predetermined voltage. 7. The vehicle power supply device according to claim 1, wherein when the voltage reaches the voltage, the charging current is bypassed to output a full charge signal. 8. A power supply device used for a commercial vehicle that travels by driving an electric motor with electric power stored in a power storage device, wherein the power storage device is divided into a capacitor group including a plurality of electric double layer capacitor cells. The capacitor cell includes an overcharge prevention unit that detects a voltage of the capacitor cell, wherein the overcharge prevention unit bypasses a charging current when the voltage of the capacitor cell reaches a predetermined voltage. A power supply device for a vehicle, which outputs a full charge signal.