JP2000278883A - Electric double layer capacitor devicf with solar battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To charge each electric double layer capacitor of an electric double layer capacitor device which supplies electric power to loads by combining solar batteries with the electric double layer capacitors from the solar batteries without connecting charge limiting circuits to the capacitors, by constituting the device by arranging a plurality of electric double layer capacitors having solar batteries connected in parallel between the terminals of the capacitors in series. SOLUTION: Between the input terminals of a DC/DC converter 10 connected with a load L on the output side, a plurality of electric double layer capacitor units PC1-PC3 with solar batteries is connected in series. The capacitor units PC1-PC3 respectively have electric double layer capacitors C1-C3 and solar batteries PV1-PV3 which are respectively connected in parallel between the terminals of the capacitors C1-C3, supply photovoltaic currents to the capacitors C1-C3 as charging currents, and are selected so that the batteries PV1-PV3 may not exceed the withstand voltages of the capacitors C1-C3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric double layer capacitor device with a solar cell which is used as a power supply for an outdoor lamp, a power supply for an outdoor display, or the like, and supplies power to a load by combining a solar cell and an electric double layer capacitor. It is.

[0002]

2. Description of the Related Art An electric double layer capacitor utilizes electric energy by electric charges accumulated in an electric double layer formed at an interface between a polarizable electrode and an electrolytic solution. It is noted that this electric double layer capacitor is capable of rapid charge / discharge and stable against repeated charge / discharge.
The development of large-capacity capacitors of several thousand F is in progress.

The withstand voltage of an electric double layer capacitor per basic cell is governed by the decomposition voltage of an electrolytic solution, and is as low as about 1 V for an aqueous solution and about 3 V for an organic electrolytic solution. For this reason, a rectangular exterior is required for high-voltage, large-capacity applications, such as motor drive power supplies, power supplies that respond to instantaneous voltage drops in various information devices such as computers, power supplies for signs on remote islands and mountains, and power supplies for outdoor lights. An electric double layer capacitor device containing a capacitor block in which a plurality of electric double layer capacitors (unit cells) are connected in series in a case is used. As an example, ten rectangular electric double layer capacitors C having a withstand voltage Vr of 3 V and a capacitance of 1600 F are connected in series and housed in a rectangular outer case. 160F capacity, 10 width
An electric double layer capacitor device having a size of about 0 × 120 × 250 mm is exemplified.

When charging a capacitor block CB in which a plurality of such electric double layer capacitors C are connected in series, variations in the basic performance (capacitance, internal resistance, etc.) of each electric double layer capacitor C, Due to a slight difference in the degree of performance deterioration, a situation may occur in which some electric double-layer capacitors are not sufficiently charged but others are overcharged. If the capacitor voltage exceeds the withstand voltage Vr and becomes excessive due to overcharging, performance degradation such as a decrease in capacitance and an increase in leakage current is caused. Therefore, conventionally, a charge limiting circuit has been proposed which limits the charging so that the terminal voltage of each of the electric double layer capacitors C connected in series does not exceed the withstand voltage Vr.

FIG. 2 is an explanatory diagram of a configuration of an electric double layer capacitor device with a charge limiting circuit, and FIG. 3 is an explanatory diagram of a configuration of a charge limiting circuit in FIG. As shown in FIG. 2, during charging, a charging current from a charging DC power supply 52 having a constant current characteristic is supplied to an electric double layer capacitor device 51 with a charge limiting circuit via a switch SW. The power from the capacitor block CB of the device 51 is supplied to the load 54 via the switch SW and the DC / DC converter 53. DC / D
The C converter 53 controls the DC voltage from the capacitor block CB in a step-down / step-up manner to supply a predetermined voltage to the load.

As shown in FIGS. 2 and 3, the charge limiting circuit indicated by the symbol A is connected in parallel to a plurality of electric double layer capacitors C constituting the capacitor block CB. When the terminal voltage reaches the withstand voltage Vr of the capacitor C, the comparator CO turns on the switching element (eg, transistor) S. When the switching element S is turned on, the charging current from the charging DC power supply 52 flowing to the capacitor C is bypassed via the switching element S and flows into the capacitor connected to the subsequent stage or its charge limiting circuit. at the same time,
The capacitor C is discharged via the switching element S, and its terminal voltage is reduced. When the capacitor terminal voltage reaches the withstand voltage Vr as described above, the charge current is bypassed to another capacitor at the same time as discharging, and a voltage exceeding the withstand voltage Vr is not applied to any electric double layer capacitor C. ing.

[0007]

However, in the electric double layer capacitor device 51 with the charge limiting circuit described above, the charging current is bypassed via the switching element S when charging the capacitor block CB. Therefore, heat generation in each switching element S is considerably large. For this reason, it is necessary to attach each switching element S to the heat radiating plate, and when mounting the printed circuit board on which the charge limiting circuit A is mounted in the outer case of the electric double layer capacitor device 51, heat radiation of the switching element S is secured. If this is attempted, the entire charge limiting circuit A including the switching element with a heat sink cannot be molded with a compound (thermoplastic insulator) or the like.

As described above, the electric double layer capacitor device 51 cannot mold the printed circuit board on which the charge limiting circuit A is mounted, and is inferior in water resistance and reliability. For this reason, there are many demands for the use of electric double-layer capacitors, and if they are to be used as power supplies for outdoor lights and outdoor displays that are strongly required to be used in combination with solar cells, they should be embedded in the ground or on the walls of buildings. And there was a problem in terms of practicality. It should be noted that both the electric double layer capacitor and the solar cell have an advantage that their life is longer than that of the chemical battery.

Accordingly, an object of the present invention is to provide a device for supplying power to a load by combining a solar cell and an electric double layer capacitor in which solar cells are connected in parallel between the terminals of one electric double layer capacitor. With the configuration in which the individual electric double layer capacitors are connected in series, the electric double layer capacitors can be charged by the solar cells without connecting a charge limiting circuit which generates a large amount of heat. An object of the present invention is to provide an electric double layer capacitor device with a solar cell excellent in practicality.

[0010]

According to a first aspect of the present invention, there is provided a power supply with a plurality of solar cells between input terminals of a DC / DC converter having a load connected to an output side. Connect the double-layer capacitor unit in series,
Each of the electric double layer capacitor units with solar cells,
One electric double layer capacitor is connected in parallel between the terminals of the electric double layer capacitor and supplies a photovoltaic current as a charging current to the electric double layer capacitor so that the withstand voltage of the electric double layer capacitor is not exceeded. And an electric double layer capacitor device with a solar cell.

According to a second aspect of the present invention, in the electric double-layer capacitor device with a solar cell according to the first aspect, each electric double-layer capacitor unit with a solar cell is provided with the first electric double-layer capacitor unit.
Two electric double-layer capacitors, and the solar cell connected between terminals of the electric double-layer capacitor via a reverse current blocking diode for passing a photovoltaic current and preventing the inflow of discharge current of the electric double-layer capacitor. And a bypass diode having a cathode connected to a positive terminal of the electric double layer capacitor and an anode connected to a negative terminal of the electric double layer capacitor. According to a third aspect of the present invention, in the electric double layer capacitor device with a solar cell according to the first or second aspect, the electric double layer capacitor is a large-capacity rectangular electric double layer capacitor. .

An electric double layer capacitor device with a solar cell according to the present invention has a DC / DC converter to which a load is connected on the output side, and a plurality of electric cells with a solar cell between input terminals of the DC / DC converter. The multilayer capacitor units are connected in series. Each unit supplies a photovoltaic current to one electric double layer capacitor as a charging current to the capacitor at the time of light irradiation, and connects in parallel solar cells selected so as not to exceed the withstand voltage of the capacitor. It is configured. Therefore, for each electric double layer capacitor unit with a solar cell, the solar cell itself plays a role as a DC charging source having a charge limiting function, so that a charge limiting circuit with a large amount of heat is not required unlike the related art. .

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an electric double layer capacitor device with a solar cell according to one embodiment of the present invention.

As shown in FIG. 1, the electric double layer capacitor device with a solar cell has a DC / DC converter 10 to which a load L is connected via a switch SW on the output side. Between input terminals,
In this example, three electric double layer capacitor units with solar cells PC1, PC2, PC3 are connected in series. By these capacitor units PC1 to PC3, three large-capacity rectangular electric double layer capacitors C are formed.
A capacitor block CB is formed by connecting 1, C2 and C3 in series. And in this embodiment,
The load L is a night light, and the capacitors C1, C2, and C3 of the capacitor block CB are charged by solar cells described below during daytime light irradiation, and the DC / DC converter converts the power from the capacitor block CB during nighttime discharge. The configuration is such that the output is made via the reference numeral 10. DC / D
The C converter 10 is a known power supply that generates a DC voltage from a DC voltage. The C converter 10 controls a DC input voltage by stepping down and stepping up, and a load SW (in this example, a night light) through a switch SW that is closed at the time of discharging to a predetermined voltage. ).

The electric double layer capacitor unit PC1 with a solar cell comprises an electric double layer capacitor C1 and a diode D1a for preventing a backflow between terminals of the capacitor C1.
And a bypass diode D connected between the terminals of the capacitor C1.
1b.

The backflow prevention diode D1a is for passing a photovoltaic current, which is a charging current from the solar cell PV1 to the electric double layer capacitor C1, while preventing the discharge current of the capacitor C1 from flowing. The bypass diode D1b has an electric double layer capacitor C on the cathode side.
1 and the anode side is connected to the negative terminal of the capacitor C1. If the electric double-layer capacitor C1 is opened due to a failure, the capacitor block CB is disconnected during discharging. This is to allow the discharge current from the remaining capacitors C2 and C3 to flow to the load by bypassing the electric double layer capacitor C1 in a defective state.

The solar cell PV1 supplies a photovoltaic current as a charging current to the electric double layer capacitor C1 during daytime light irradiation. The solar cell PV1 is selected such that its open-circuit voltage Voc is equal to the withstand voltage Vr of the electric double layer capacitor C1 plus a voltage drop ΔV due to the circuit impedance of the device (Voc = Vr + ΔV). . Therefore, the solar cell PV1 is connected to the electric double layer capacitor C1.
, The electric double layer capacitor C1 can be charged up to the full withstand voltage Vr (for example, 3 V).

The electric double layer capacitor units with solar cells PC2 and PC3 connected in series to the capacitor unit PC1 in order have the same configuration as the capacitor unit PC1, as shown in FIG. That is, the capacitor unit PC2 includes an electric double layer capacitor C2,
A diode D2 for preventing backflow between the terminals of the capacitor C2;
a, and a bypass diode D2b connected between the terminals of the capacitor C2.
It is composed of Similarly, the capacitor unit PC3 includes an electric double layer capacitor C3,
3 comprises a solar cell PV3 connected between the terminals of the capacitor C3 via a backflow preventing diode D3a, and a bypass diode D3b connected between the terminals of the capacitor C3.

As described above, a plurality of, in this example, three, electric double layer capacitor units with solar cells PC1, PC2, PC3 are connected in series between the input terminals of the DC / DC converter 10 in which the load L is connected to the output side. Connected to
And the respective capacitor units PC1 to PC3
However, a photovoltaic current is supplied to the electric double layer capacitor as a charging current to the capacitor, and solar cells selected so as not to exceed the withstand voltage of the capacitor are connected in parallel. Therefore, each of the capacitor units PC1 to PC1
Since the solar cell itself plays a role as a DC charging source having a charge limiting function for each PC 3, a charge limiting circuit that generates a large amount of heat is unnecessary unlike the related art. Further, by selecting each of the solar cells PV1, PV2, and PV3 so that the generated voltages are the same, each electric double layer capacitor C
Variations in voltage due to charging of C1, C2, and C3 can be eliminated, and the entire capacitor block CB can be charged to the maximum limit.

In the above embodiment, the case where the load L is a night outside light is described. However, the present invention is not limited to this, and the present invention can be applied to a case where the load L is, for example, a solar clock or an outdoor display panel. Each capacitor unit PC1
It is also possible to charge the electric double layer capacitor with the excess current from the solar cell for each PC3 and supply the discharge current from the capacitor block CB to the load L when the light is temporarily blocked or at night. is there.

[0021]

As described above, in the electric double layer capacitor device with a solar cell according to the present invention, in a device for supplying power to a load by combining a solar cell and an electric double layer capacitor, the load is connected to the output side. By connecting a plurality of solar cells connected in parallel between the terminals of one electric double layer capacitor between the input terminals of a DC / DC converter, the solar cells have a charge limiting function. Since it is configured to serve as a DC charging source, it does not exceed the withstand voltage without connecting a charge limiting circuit with large heat generation to each of a plurality of electric double layer capacitors connected in series. Can be charged.

This eliminates the need for providing a heat sink or the like,
For example, when used as a power supply for night outside lights, the apparatus main body can be installed underground or embedded in a wall of a building. Therefore, according to the present invention, it is possible to provide an electric double-layer capacitor device with a solar cell which does not require any heat radiation measures and is excellent in practicality.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an electric double layer capacitor device with a solar cell according to an embodiment of the present invention.

FIG. 2 is a configuration explanatory view of an electric double layer capacitor device with a charge limiting circuit showing a conventional technique.

FIG. 3 is a diagram illustrating a configuration of a charge limiting circuit in FIG. 2;

[Explanation of symbols]

10 DC / DC Converters PC1 to PC3 Electric Double Layer Capacitor Unit with Solar Cell CB Capacitor Block C1 to C3 Electric Double Layer Capacitor PV
1 to PV3: Solar cell D1a to D3a: Backflow preventing diode D1b to D3b: Bypass diode

Claims (3)

[Claims] 1. A plurality of electric double layer capacitor units with solar cells are connected in series between input terminals of a DC / DC converter to which a load is connected on the output side, and each of said electric double layer capacitor units with solar cells is connected One electric double layer capacitor and a photovoltaic current which is connected in parallel between the terminals of the electric double layer capacitor as a charging current to the electric double layer capacitor and does not exceed the withstand voltage of the electric double layer capacitor An electric double-layer capacitor device with a solar cell, comprising: a solar cell selected as described above. 2. Each of the electric double layer capacitor units with solar cells is connected to the one electric double layer capacitor and a reverse current blocking diode for passing a photovoltaic current and preventing a discharge current from flowing into the electric double layer capacitor. The solar cell connected between the terminals of the electric double-layer capacitor through the cathode, the cathode side is connected to the positive terminal of the electric double-layer capacitor, and the anode side is connected to the negative terminal of the electric double-layer capacitor The electric double-layer capacitor device with a solar cell according to claim 1, comprising a bypass diode. 3. The electric double layer capacitor device with a solar cell according to claim 1, wherein the electric double layer capacitor is a large-capacity rectangular electric double layer capacitor.