JP4264910B2 - Electric double layer capacitor with withstand voltage measures - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively obtain an electric double-layered capacitor which has no change in capacitance and a target breakdown voltage, using generally available inexpensive semiconductor elements, etc. SOLUTION: A const.-voltage circuit 20, coupled with an electric double layer capacitor 10, has a charging terminal 23 to which the collector of a transistor 22 and the anode of a const.-current element 21 are connected, the emitter of the transistor 22 is connected to a common terminal 25 through a resistor 26 and electric double-layered capacitor 10, the cathode of the const.-current element 21 is connected to the base of the transistor 22 and cathode of a three- terminal Zener diode 30, the anode of which is connected to the common terminal 25 and the reference terminal of which is connected to a connection point of the emitter of the transistor 22 and the resistor 26. A DC/DC converter 27 is connected between an output terminal 24 taken from the connection point of the resistor 26 and electric double-layered capacitor 10 and common terminal 25 so as to output a const. voltage.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electric double layer capacitor with a withstand voltage countermeasure that can be an electric double layer capacitor having a high withstand voltage by adding a simple electric circuit or electronic element.
[0002]
[Prior art]
The electrical conductor that is an electrolyte serves as a dielectric below the decomposition voltage. There is an electric double layer capacitor 10 using this phenomenon.
Specifically, this electric double layer capacitor 10 has a polarizability-electrode similar to the polarizability + electrode 13 in which activated carbon is applied to an aluminum foil, the separator 15 impregnated with an electrolyte, and the polarizability + electrode 13 in FIG. 14. Further, the same separator 15 as described above is sequentially overlapped and wound into a columnar shape, and this is housed in a cylindrical aluminum container 12 together with a sealing rubber 17, and lead wires 18 and 19 connected to the electrodes 13 and 14 are connected. It is derived from the sealing rubber 17 of the cylindrical aluminum container 12. The whole shape may be other than a cylindrical shape.
[0003]
The electric double layer capacitor 10 has advantages such that a large capacity capacitor can be made small, can be charged in a short time, and can have a very long life. However, there is a problem that the withstand voltage is as low as 1 to 2.5V.
[0004]
[Problems to be solved by the invention]
In order to double the withstand voltage, a series circuit 11 in which two electric double layer capacitors 10 of the same rating are connected in series between terminals A and B may be used as shown in FIG.
However, this will halve the capacity. The same applies when the withstand voltage is increased n times.
[0005]
In order to make the withstand voltage double and the capacitance does not change, as shown in FIG. 5B, first, two series circuits 11 in which two electric double layer capacitors 10 are connected in series are formed. Two series circuits 11 may be connected in parallel between the terminals A and B.
However, in this case, four electric double layer capacitors 10 must be used. In order to further increase the withstand voltage, there is a problem that the number of electric double layer capacitors 10 is increased.
[0006]
An object of the present invention is to use a general-purpose inexpensive semiconductor element without increasing the number of capacitors, and to obtain an electric double layer capacitor having a desired breakdown voltage at a low price without changing the capacitance of the capacitor. To do.
[0007]
The present invention combines an electric double layer capacitor with a constant voltage circuit that outputs a voltage that does not exceed the withstand voltage of the electric double layer capacitor. The constant voltage circuit includes an input terminal for a charge input voltage and an output for a discharge output voltage. The collector of the transistor as the control unit and the anode of the constant current element are connected to the + side terminal, which is also used as a terminal, via a Zener diode having a threshold for applying a voltage higher than the discharge output voltage as a charge input voltage by a predetermined value or more. and the emitter of the transistor, via a resistor and the electric double layer capacitor as a detection end - connected to the side common terminal, the cathode of the constant current element, the cathode of the base and 3 terminal zener diode of the transistor connect the anode of the three-terminal zener diode - connected to the side common terminal, the three-terminal zener diode Of the reference terminal, will be connected to the connection point of the resistor as an emitter and the detection end of said transistors, said output terminal taken out from a connection point between the resistor and electric double layer capacitor as the detection end - side common connect the DC-DC converter between the terminals, by connecting pre SL via a DC-DC converter diode for preventing reverse current on the output side of said positive terminal, the positive terminal and the - side common terminal This is an electric double layer capacitor with a withstand voltage measure characterized by being a two-terminal type.
[0008]
In such a configuration, a voltage is applied from the charging terminal to the anode of the constant current element and the collector of the transistor. In the constant current element, a constant current flows as the base current of the transistor, and the collector current of the transistor has a resistance. Then, it flows into the electric double layer capacitor and charges.
[0009]
The potential generated at both ends of the resistor is applied between the reference terminal and the anode of the three-terminal Zener diode. When this potential becomes equal to the reference voltage of the three-terminal Zener diode, the three-terminal Zener diode becomes conductive and the three terminals. A control operation for performing a desired constant current operation is applied to the base of the transistor from the cathode of the Zener diode, and the current flowing to the electric double layer capacitor is made constant.
The DC voltage at the output terminal is chopped by the boosting DC-DC converter IC, boosted by the boosting choke coil, and then the pulsating wave is smoothed and output.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a first embodiment of an electric double layer capacitor with a withstand voltage countermeasure according to the present invention, and a constant voltage circuit 20 is connected to the charging voltage input side of the electric double layer capacitor 10 to discharge voltage. A DC-DC converter 27 is connected to the output side, and is configured as a two-terminal type including a terminal 23 and a common terminal 25. Of these two terminals, the terminal 23 serves as both an input terminal in the charge mode and an output terminal in the discharge mode.
[0011]
The constant voltage circuit 20 is connected from a terminal 23 to a collector of a transistor 22 as a control unit via a Zener diode 29 and is connected to an anode of a constant current element 21 as a constant current unit. Is connected to a resistor 26 as a voltage detection terminal, further connected to the + side of the electric double layer capacitor 10, and the cathode of the constant current element 21 is connected to the base of the transistor 22, The anode of the three-terminal Zener diode 30 is connected to the negative side of the electric double layer capacitor 10 and to the common terminal 25, and the three-terminal Zener diode 30 is connected to the common terminal 25. The reference terminal of the Zener diode 30 is the emitter of the transistor 22. And connected to said connection point of the resistors 26, between the cathode and the reference terminal of the three terminal zener diode 30 is for preventing oscillation capacitor 31 is inserted.
[0012]
The DC-DC converter 27 mainly includes a step-up DC-DC converter IC 33, and includes a current limiting resistor 34, a boost choke coil 35, a rectifying Schottky diode 36, and a smoothing electrolytic capacitor 37. The output terminal 24 taken out from the connection point of the resistor 26 and the electric double layer capacitor 10 is connected to the current limiting resistor 34, the first terminal of the step-up DC-DC converter IC 33, and the step-up choke coil 35, The connection point between the cathode of the rectifying Schottky diode 36 and the eighth terminal of the step-up DC-DC converter IC 33 is connected to the common terminal 25 via the backflow preventing diode 32.
[0013]
The effect | action by such a structure is demonstrated.
A predetermined voltage Vi (for example, 7 V) is applied to the terminal 23. When the voltage Vi is higher than the Zener voltage Vz of the Zener diode 29 and the voltage exceeding the threshold value on the anode side of the Zener diode 29 is a predetermined value (for example, 2 V) or more, the constant voltage circuit 20 and the electric double layer The capacitor 10 starts to operate as a charging mode.
The voltage Vd that has passed through the Zener diode 29 is applied to the anode of the constant current element 21 and the collector of the transistor 22. In the constant current element 21, the constant current flows as the base current Ib of the transistor 22 and is multiplied by h _FE. The electric current flows into the electric double layer capacitor 10 through the resistor 26 as the collector current Ic of the transistor 22 and charges the electric double layer capacitor 10.
[0014]
The collector current Ic is stabilized by the stability of the base current Ib and the ambient temperature.
That is, the potential Va generated at both ends of the resistor 26 is applied between the reference terminal and the anode of the three-terminal Zener diode 30, and this potential Va is equal to the reference voltage Vr (for example, 2.5 V) of the three-terminal Zener diode 30. When the three-terminal Zener diode 30 is turned on, the control operation for performing the desired constant current operation is applied to the base of the transistor 22 from the cathode of the three-terminal Zener diode 30, and the base current amount Ib is controlled. A constant current is supplied to the double layer capacitor 10.
[0015]
When the output voltage Vc of the + side output terminal 24 of the electric double layer capacitor 10 becomes a predetermined voltage, for example, 1.5 V or more, the step-up DC-DC converter IC 33 starts normal operation. The DC voltage of the output terminal 24 is chopped by the boosting DC-DC converter IC 33, boosted by the boosting choke coil 35, and then passed through the rectifying Schottky diode 36 from the third output terminal, followed by a sawtooth wave, rectangular A pulsating wave such as a wave is output, smoothed by the smoothing electrolytic capacitor 37, and sent from the backflow prevention diode 32 to the terminal 23.
[0016]
The output voltage Vo of the DC-DC converter 27 is lower than the applied voltage Vi in the charging mode, for example, set to 5 V. When the application of the charging voltage Vi is stopped, the terminal 23 is connected via the backflow preventing diode 32. Output from.
The backflow prevention diode 32 functions as a protective element for preventing the charging voltage Vi from being applied to the eighth terminal of the step-up DC-DC converter IC 33 in the charging mode. That is, the charging voltage Vi applied in the charging mode acts as a switching element that applies a reverse bias to the cathode of the backflow prevention diode 32 and stops the output of the boosting DC-DC converter IC 33.
[0017]
In the embodiment shown in FIG. 1, the terminal 23 and the common terminal 25 are used as two terminals so that the discharging voltage cannot be taken out from the terminal 23 during charging, and charging and discharging timings are required. That is, the two-terminal type has the following properties.
(1) During the charge mode, the discharge mode does not operate.
(2) A difference occurs in the output voltage supplied to the load circuit during charging and discharging.
(3) The charging voltage is always a constant voltage higher than the discharge output voltage, in the embodiment, 2V higher.
[0018]
However, in the second embodiment of the present invention shown in FIG. 2, a terminal 23 for charging and an output terminal 28 for outputting a discharge voltage are provided separately, and three terminals are combined with the common terminal 25. . The terminal 23 is directly connected to the transistor 22 and the constant current element 21 without passing through the Zener diode 29, and the output terminal 28 has a backflow prevention diode 32 interposed at the output terminal of the DC-DC converter 27. Connect directly without
[0019]
The operation of the second embodiment shown in FIG. 2 will be described.
A voltage Vi in the range of 3 to 50 V is constantly applied to the terminal 23.
This voltage Vi is applied to the anode of the constant current element 21 and the collector of the transistor 22. In the constant current element 21, the constant current flows as the base current Ib of the transistor 22, and the current multiplied by hFE becomes the current of the transistor 22. The collector current Ic flows into the electric double layer capacitor 10 through the resistor 26, and the electric double layer capacitor 10 is charged.
[0020]
When the potential Va generated at both ends of the resistor 26 becomes equal to the reference voltage Vr of the three-terminal Zener diode 30, the three-terminal Zener diode 30 is turned on to perform a constant current operation to be obtained from the cathode of the three-terminal Zener diode 30. For this purpose, a control operation is applied to the base of the transistor 22 to perform a bleeder operation of the base current amount Ib, thereby making the current flowing to the electric double layer capacitor 10 constant.
[0021]
When the output voltage Vc at the output terminal 24 becomes equal to or higher than a predetermined voltage, the boosting DC-DC converter IC 33 starts normal operation, and the DC voltage is chopped by the boosting DC-DC converter IC 33, and the boosting choke coil After being boosted at 35, the voltage is smoothed by the smoothing electrolytic capacitor 37 and output from the output terminal 28.
The output voltage Vo of the DC-DC converter 27 is output even in the charging mode.
[0022]
The three-terminal type second embodiment shown in FIG. 2 has the following properties.
(1) It can operate simultaneously without distinction between charging and discharging. However, at the time of starting, it is necessary that the electric double layer capacitor 10 is charged to a voltage that can drive the step-up DC-DC converter IC 33, for example, 1.5 V or more.
(2) The charging voltage can be charged even if it is an unstable voltage of 3 to 50V.
(3) A constant output voltage can always be supplied to the load circuit connected to the output terminal 28.
(4) The discharge voltage is stable even if the charging voltage fluctuates up and down.
[0023]
In the example shown in FIG. 1 and FIG. 2, the withstand voltage of the electric double layer capacitor 10 is 2.5 V. However, when the electric double layer capacitor 10 having a lower withstand voltage is used by using these circuits as they are, This will be described with reference to FIGS.
FIG. 3A shows an example in which two diodes 38 having a threshold voltage of 0.6 V are inserted in series between the resistor 26 and the positive side of the electric double layer capacitor 10. In this way, the electric double layer capacitor 10 having a withstand voltage of 2.5−0.6−0.6 = 1.3V can be applied.
FIG. 3B shows an example in which one Zener diode 39 having a Zener voltage Vz of 1.0 V is inserted between the resistor 26 and the + side of the electric double layer capacitor 10. In this way, the electric double layer capacitor 10 having a withstand voltage of 2.5−1.0 = 1.5V can be applied.
FIG. 3C shows an example in which a variable resistor 40 is inserted between the resistor 26 and the positive side of the electric double layer capacitor 10. In this way, adjustment of the resistance value of the variable resistor 40 can be adapted to the electric double layer capacitor 10 having a desired withstand voltage.
[0024]
FIG. 4 shows an example in which an electronic circuit composed of the constant voltage circuit 20 and the DC-DC converter 27 as shown in FIGS. 1 to 3 is integrated into the electric double layer capacitor 10 and integrated as one electronic element. ing.
In FIG. 4, reference numeral 41 denotes a wiring board having a disk shape that is slightly smaller than the diameter of the cylindrical aluminum container 12 of the electric double layer capacitor 10, and printed on one side surface (lower surface in the figure) of the wiring board 41. In addition to wiring, various circuit elements 42 necessary for the circuit shown in FIG. 1 or 2 are mounted, and the constant voltage circuit 20 and the electronic circuit of the DC-DC converter 27 are configured. In the case of the circuit configuration shown in FIG. 1, the terminal substrate 43 having substantially the same shape as the wiring substrate 41 includes two terminals 23 and a common terminal 25, and in the case of the circuit configuration shown in FIG. 23, a common terminal 25, and an output terminal 28 are attached.
[0025]
The wiring board 41 is fitted into the upper edge 45 of a cylindrical holding frame 44 made of nickel-plated phosphor bronze from the inside and is held by a folding claw 46 cut and raised from the slit 47, and the terminal board 43 is wired. The substrate 41 is held by an extension piece of the spring portion 48 of the holding frame 44 so as to face the substrate 41 with a predetermined interval.
When the assembly of the wiring board 41, the terminal board 43, and the holding frame 44 is fitted inside a cylindrical adapter case 52 of a size that fits on the outer periphery of the cylindrical aluminum container 12, the terminals The board 43 abuts on the winding portion 49 of the adapter case 52, and the folding claws 53 of the adapter case 52 are folded and fixed to the upper surface of the upper edge portion 45 of the holding frame 44. In this way, the two terminals or the three terminals protrude outward from the winding portion 49 side of the adapter case 52.
[0026]
Thus, the adapter case 52 in which the electronic circuit is incorporated is fitted into the cylindrical aluminum container 12 of the electric double layer capacitor 10 from below at the crimping portion 50 side opened at the upper end. A heat radiating hole 51 is formed in the crimping portion 50 at a location coinciding with the concave groove 54 of the cylindrical aluminum container 12. By narrowing the outer peripheral portion where the heat radiating hole 51 is located, the adapter case is attached to the cylindrical aluminum container 12. 52 are fixed together. At this time, the lead wire 18 and the lead wire 19 of the electric double layer capacitor 10 are inserted into the wiring portion of the wiring substrate 41 and connected by soldering or the like from the hole formed in the terminal substrate 43.
Thus, by fitting and fixing the adapter case 52 containing the electronic circuit on the lead wire side of the conventional electric double layer capacitor 10, the appearance is almost the same as that of the electric double layer capacitor 10 alone, and the resistance is also improved. An electric double layer capacitor with an increased voltage can be obtained.
[0027]
【The invention's effect】
According to the present invention, the constant voltage circuit 20 including the transistor 22 as the control unit, the constant current element 21, the resistor 26 as the detection terminal, and the three-terminal Zener diode 30 is connected to the electric double layer capacitor 10. Using an inexpensive semiconductor element or the like, a low withstand voltage of 1 to 2.5 V can be upgraded to a high withstand voltage electric double layer capacitor of at least 3 to 50 V. Further, there is little heat generation due to voltage fluctuation applied during charging. In particular, the constant current element 21 stabilizes heat generation and reduces heat loss. Furthermore, even if there is some heat generation by the resistor 26, it is a constant value and is stable.
[0028]
According to the present invention, in addition to the constant voltage circuit 20 including the transistor 22 as the control unit, the constant current element 21, the resistor 26 as the detection terminal, and the three-terminal Zener diode 30 in the electric double layer capacitor 10, the DC-DC By connecting the converter 27, a stable discharge voltage can be output.
[0029]
The electric double layer capacitor to which the withstand voltage measure of the present invention is applied has the following properties by making it a two- terminal type .
(1) During the charge mode, the discharge mode does not operate.
(2) A difference occurs in the output voltage supplied to the load circuit during charging and discharging.
(3) The charging voltage is always a constant voltage higher than the discharge output voltage, in the embodiment, 2V higher.
[0030]
By interposing one or a plurality of diodes 38, a Zener diode 39, or a variable resistor 40 between the resistor 26 serving as the detection end and the electric double layer capacitor 10, it is possible to adapt to the electric double layer capacitor 10 having different withstand voltages.
[0031]
An adapter case 52 incorporating an electronic circuit of the constant voltage circuit 20 and the DC-DC converter 27 is fitted and fixed to the cylindrical aluminum container 12 of the electric double layer capacitor 10, and the terminal 23 and the common terminal are connected from the other end of the adapter case 52. 25, or the three terminals of the terminal 23, the common terminal 25, and the output terminal 28 are projected to the outside, so that the appearance is hardly changed from that of the conventional single electric double layer capacitor 10 and the withstand voltage is reduced. A high electric double layer capacitor 10 is obtained.
[Brief description of the drawings]
FIG. 1 is an electric circuit diagram showing a first embodiment of an electric double layer capacitor having a withstand voltage countermeasure according to the present invention.
FIG. 2 is an electric circuit diagram showing a second embodiment of an electric double layer capacitor with a withstand voltage countermeasure according to the present invention.
3A and 3B show an embodiment for adapting to an electric double layer capacitor 10 having different withstand voltages. FIG. 3A is an electric circuit diagram showing an example in which a diode 38 is inserted, and FIG. FIG. 4C is an electric circuit diagram showing an example in which a Zener diode 39 is inserted, and FIG. 5C is an electric circuit diagram showing an example in which a variable resistor 40 is inserted.
FIG. 4 is a partially cutaway front view showing an example in which an adapter case 52 incorporating an electronic circuit is fitted and fixed to an electric double layer capacitor with a withstand voltage measure according to the present invention.
5A is an electric circuit diagram when the withstand voltage of the electric double layer capacitor 10 is doubled, and FIG. 5B is an electric circuit diagram when the withstand voltage is doubled without changing the capacitance. It is.
6 is a perspective view showing an example of a general electric double layer capacitor 10. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Electric double layer capacitor, 11 ... Series circuit, 12 ... Cylindrical aluminum container, 13 ... Polarizability + electrode, 14 ... Polarizability-electrode, 15 ... Separator, 17 ... Sealing rubber, 18 ... Lead wire, 19 ... Lead Line 20, constant voltage circuit, 21, constant current element, 22, transistor as control unit, 23, terminal, 24, output terminal, 25, common terminal, 26, resistance as detection terminal, 27, DC-DC converter 28 ... Output terminal, 29 ... Zener diode, 30 ... 3-terminal Zener diode, 31 ... Oscillation prevention capacitor, 32 ... Backflow prevention diode, 33 ... Step-up DC-DC converter IC, 34 ... Limited flow resistance, 35 ... Boost choke coil, 36 ... Schottky diode for rectification, 37 ... Smoothing electrolytic capacitor, 38 ... Diode, 39 ... Zener Diode, 40 ... Variable resistance, 41 ... Wiring board, 42 ... Circuit element, 43 ... Terminal board, 44 ... Holding frame, 45 ... Upper edge, 46 ... Folding claw, 47 ... Slot, 48 ... Spring part, 49 ... Entrainment part, 50 ... crimping part, 51 ... heat dissipation hole, 52 ... adapter case, 53 ... folding claw, 54 ... concave groove.

Claims (5)

A constant voltage circuit that outputs a voltage that does not exceed the withstand voltage of the electric double layer capacitor is coupled to the electric double layer capacitor, and this constant voltage circuit combines the input terminal for the charge input voltage and the output terminal for the discharge output voltage. + the positive terminal, connecting the anode collector and the constant current element of the transistor as a control unit via a Zener diode having a threshold value for applying a predetermined or higher voltage than the discharge output voltage as a charging input voltage, said transistor the emitter, through the resistor and the electric double layer capacitor as a detection end - connected to the side common terminal, the cathode of the constant current element is connected to the cathode of the base and the three-terminal zener diode of the transistor, this wherein the anode of the three-terminal zener diode - connected to the side common terminal, referencing the three-terminal zener diode The Nsu terminals, constituted by connecting to a connection point of the resistance of the emitter and the detection end of said transistors, said output terminal taken out from a connection point between the resistor and electric double layer capacitor as the detection end - side common terminal connect the DC-DC converter between, by connecting before Symbol DC-DC converter of the positive terminal through a diode for preventing reverse current on the output side, the positive side terminal and the - and the side common terminal An electric double layer capacitor with a withstand voltage characteristic characterized by being a two-terminal type. To accommodate the withstand voltage of the electric double layer capacitor, according to claim 1 Symbol placement breakdown voltage, characterized by comprising interposed one or more diodes between the electric double layer capacitor and a resistor as a detection end Electric double layer capacitor with countermeasures. To accommodate the withstand voltage of the electric double layer capacitor, facilities the withstand voltage protection according to claim 1 Symbol mounting, characterized by comprising interposing a Zener diode between the resistor and the electric double layer capacitor as a detection end Electric double layer capacitor. To accommodate the withstand voltage of the electric double layer capacitor, facilities the withstand voltage protection according to claim 1 Symbol placement and characterized by being interposed a variable resistor to the resistance of the detection end the electric double layer capacitor Electric double layer capacitor. The adapter case incorporating the electronic circuit of the constant voltage circuit and the DC-DC converter is fitted and fixed to the container of the electric double layer capacitor, and the two terminals of the + side terminal and the − side common terminal are connected from the other end of the adapter case. 2. The electric double layer capacitor with a withstand voltage countermeasure according to claim 1, wherein the electric double layer capacitor is protruded to the outside.

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