JP2003235175A - Apparatus and method for charging electric double layer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformly charge a plurality of electric double layer capacitors connected in series without a balancing resistor or a bypass circuit. <P>SOLUTION: Switch elements 52-1 and 52-2 are only brought into conduction, and the charging voltage V1 of an electric double layer capacitor 10-1 is detected by a common voltage detecting means 56. Next, switch elements 12-1 and 12-2 are only brought into conduction, and the electric double layer capacitor 10-1 is charged with a constant current through a DC-DC converter 26 only for a time (a+k/Vm) based on the charging voltage V1. These voltage detecting and charging operations are repeatedly performed more than once sequentially with respect to each of electric double layer capacitors 10-1 to 10-n until the charging voltage approaches a rated voltage. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device and method for an electric double layer capacitor used as a rechargeable power storage device, and more particularly to a charging device and method for charging a plurality of electric double layer capacitors connected in series.

[0002]

2. Description of the Related Art Electric double layer capacitors have been used as electric storage devices that are repeatedly used. The electric double layer capacitor is capable of rapid charging / discharging with a large current and has a feature of long life. On the other hand, since the rated voltage per unit is low, usually multiple capacitors are connected in series and used. Often. The electric double layer capacitor can be efficiently used by charging it to the full rated voltage, but it has a characteristic that it is rapidly deteriorated if it is charged more than the rated voltage. Therefore, when charging multiple electric double layer capacitors connected in series at the same time, we want to charge each capacitor evenly to the full rated voltage, but in reality, due to the variation in the capacity of each capacitor The time required for each capacitor is different. Therefore, it is necessary to perform charging while monitoring the charging voltage of each capacitor so as not to exceed the rated voltage.

As an example of a conventional apparatus for charging a plurality of electric double layer capacitors connected in series, a plurality of capacitors connected in series are simultaneously charged using one charging power source. In that case, the charging voltage of each capacitor is monitored, and the current flowing from the charging power supply to the capacitor is controlled so that the charging voltage of the capacitor does not exceed the rated voltage. Therefore, a balance resistor is provided in parallel with each capacitor, and a current is caused to flow through this balance resistor, thereby suppressing variations in charging voltage due to variations in capacitance of each capacitor. Alternatively, a bypass circuit may be provided in parallel with each capacitor, and a capacitor charged to the rated voltage may be charged by flowing a current through the bypass circuit and controlling the bypass circuit so as not to exceed the rated voltage.

[0004]

However, in the conventional device in which the balance resistor or the bypass circuit is provided in parallel with each capacitor, the electric power from the charging power source is stored as the electric energy of the capacitor. , It will be consumed in the balance resistor or the bypass circuit. In particular, in an electric double layer capacitor, since a large current is handled, the power consumed in the balance resistor or the bypass circuit becomes large, so that the charging efficiency deteriorates, and the balance resistor is not disconnected during discharging. There was a problem of self-discharge.

The present invention has been made in view of the above problems, and when charging a plurality of electric double layer capacitors connected in series, it is possible to perform uniform voltage charging without a balance resistor or a bypass circuit. An object of the present invention is to provide a charging device and method for a double layer capacitor.

[0006]

In order to achieve such an object, a charging device for an electric double layer capacitor according to a first aspect of the present invention is a device for charging a plurality of electric double layer capacitors connected in series. And a first charging power source for charging the electric double layer capacitor, a charging switching means for sequentially switching the electric double layer capacitor connected to the first charging power source, and each of the electric double layer capacitors. A voltage detection unit that detects a charging voltage, and a charge control that controls the electric energy stored in the electric double layer capacitor from the first charging power source based on the charging voltage value of the electric double layer capacitor by the voltage detection unit. Means and are provided.

As described above, since the electric energy stored in the electric double layer capacitor from the first charging power source is controlled based on the charging voltage value of the electric double layer capacitor, a plurality of electric capacitors connected in series are connected. When charging each of the multi-layer capacitors, it is possible to suppress variations in the charging voltage due to variations in the capacitance of the capacitors without passing a current through the balance resistor or the bypass circuit. Therefore, it is possible to charge the electric double layer capacitors so that the voltages of the electric double layer capacitors are equalized without using a balance resistor or a bypass circuit.

An electric double layer capacitor charging device according to a second aspect of the present invention is the device according to the first aspect of the present invention, wherein the electric double layer capacitor is provided in parallel with the first charging power source, and the entire electric double layer capacitor is provided. Is further provided with a second power supply for charging.

As described above, the first charging power source and the second charging power source for charging the entire electric double layer capacitor are provided, so that the first charging power source has a small capacity. The charge switching means for sequentially switching the electric double layer capacitors connected to the first charging power source may be of a small capacity. Therefore, it is possible to reduce the cost of the charging device for an electric double layer capacitor that can be uniformly charged. Further, by providing the second charging power source, it is possible to shorten the time required to uniformly charge the battery up to the rated voltage.

An electric double layer capacitor charging device according to a third aspect of the present invention is the device according to the first or second aspect of the present invention, wherein the charging control means is the electric double layer capacitor based on the voltage detecting means. By controlling the time for connecting the first charging power source and the electric double layer capacitor by the charge switching means on the basis of the charging voltage value of the first charging power source from the first charging power source to the electric double layer capacitor. It is characterized by controlling the stored electric energy.

An electric double layer capacitor charging device according to a fourth aspect of the present invention is the device according to any one of the first to third aspects of the present invention, wherein the voltage detecting means is a charging voltage of the electric double layer capacitor. And a voltage switching means for sequentially switching and connecting the common voltage detecting means to each of the electric double layer capacitors.

Thus, by providing the common voltage detecting means for detecting the charging voltage of the electric double layer capacitor and the means for sequentially switching and connecting the common voltage detecting means to each of the electric double layer capacitors, one common voltage is obtained. The detection means can be used to detect the charging voltage of each of the plurality of electric double layer capacitors connected in series, and the cost of the charging device can be reduced.

A fifth aspect of the present invention is a method of charging an electric double layer capacitor, which is a method using the device according to any one of the first to fourth aspects of the present invention, wherein the voltage detecting means detects the charging voltage. And controlling the electric energy by the charging control means is repeated a plurality of times while sequentially switching each of the electric double layer capacitors.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention (hereinafter referred to as embodiments) will be described below with reference to the drawings.

(1) First Embodiment FIG. 1 is a block diagram showing the configuration of a charging device for an electric double layer capacitor according to the first embodiment of the present invention. A plurality of electric double layer capacitors 10-1 to 10 connected in series
One of the electric double layer capacitors 10-m (m
Is any one of 1 to n, and n is a natural number) of the positive electrode terminal 28.
-M and the negative side electrode terminal 30-m are respectively connected to switching elements 12-m and 14-m as charge switching means, and the positive side electrode terminal 28-m is connected to the switching element 12-m.
m of the switching element 14-m is connected to the negative electrode terminal 30-m. Each of the other terminals of the switch elements 12-1 to 12-n is connected to one line on the way and connected to the positive terminal 32 of the DC-DC converter 26 as the first charging power source, and the switch element 14- Each of the other terminals of 1 to 14-n is coupled to one line on the way and connected to the negative terminal 34 of the DC-DC converter 26. A DC voltage is input to the DC-DC converter 26. Furthermore, the electric double layer capacitor 10-
Both the positive electrode terminal 28-m and the negative electrode terminal 30-m of the switch element 52- serving as voltage switching means.
m, 54-m are respectively connected, and the positive electrode terminal 28-
One terminal of the switch element 52-m is connected to m, and one terminal of the switch element 54-m is connected to the negative electrode terminal 30-m. Each of the other terminals of the switch elements 52-1 to 52-n and each of the other terminals of the switch elements 54-1 to 54-n are coupled to one line on the way and input to the common voltage detecting means 56. Switch elements 12-1 to 12-1
12-n, 14-1 to 14-n, 52-1 to 52-n,
The output of the switch control circuit 24 as a charging control unit is connected to each of the control terminals 54-1 to 54-n. As the switch element, for example, FET, bipolar transistor or relay is used. DC-D with each of the other terminals of the switch elements 14-1 to 14-n
A current detection resistor 20 is provided on a line coupled to one line between the negative side terminals 34 of the C converter 26, and both terminals are input to the current control circuit 22. Then, the detection value of the common voltage detecting means 56 is also input to the current control circuit 22. The current control circuit 22 controls the pulse width or amplitude of a switching regulator (not shown) provided in the DC-DC converter 26 based on the current detection value of the current detection resistor 20 and the detection value of the common voltage detection means 56. Thus, the current flowing from the DC-DC converter 26 to the electric double layer capacitor 10-m is controlled. Further, the current control circuit 22 controls the DC-value so that the current detection value by the current detection resistor 20 does not exceed the predetermined value Imax.
DC converter 26 to electric double layer capacitor 10-m
Limits the current flowing to. The detection value of the common voltage detection means 56 is input to the switch control circuit 24, and the conduction of the switch elements 12-m and 14-m is controlled based on the detection value. Although not shown, the positive electrode terminal 28-
A load is further connected between 1 and the negative electrode terminal 30-n.

Next, the operation of this embodiment will be described. In this embodiment, the electric double layer capacitor 10-m
The charging voltage is first detected before performing the charging operation, and the charging operation is performed based on the detected voltage value. However, if the detected charging voltage reaches a value near the rated voltage,
The charging operation shown below is stopped.

First, switch elements 52-1 and 54- connected to one electric double layer capacitor 10-1 for charging.
A voltage is supplied from the switch control circuit 24 to only one control terminal, and only the switch elements 52-1 and 54-1 are made conductive. In this state, the common voltage detecting means 56 detects the charging voltage of the electric double layer capacitor 10-1. After detecting the charging voltage, the switch element 52 which has been in conduction
-1, 54-1 is made non-conducting, and the switch element 12 connected to the electric double layer capacitor 10-1 for charging at the same time
-1, 14-1 control terminals 24 only switch control circuit 24
Voltage is supplied from the switch elements 12-1 and 14
Only -1 is conducted. In this state, a current flows from the DC-DC converter 26 to the electric double layer capacitor 10-1 and charging is performed. At this time, the DC-DC converter 26
The preset output voltage is set higher than the charging voltage detection value of the electric double layer capacitor 10-1 detected by the common voltage detecting means 56. The current control circuit 22 includes the DC-DC converter 2
The current flowing from 6 to the electric double layer capacitor 10-1 is controlled to have a constant value I.

In this embodiment, DC-DC
Electric Double Layer Capacitor 10 for Charging with Converter 26
-1 is set by the switching elements 12-1 and 14-1 to be conductive, that is, the charging time is set to (a + k / V1),
The switch control circuit 24 keeps the switch element 12 for this time.
A voltage is supplied to the control terminals of -1, 14-1. here,
V1 is the charging voltage detection value of the electric double layer capacitor 10-1 detected by the common voltage detecting means 56, and the values of a and k are experimentally set. As described above, in the present embodiment, the switch control circuit 24 controls the charging time of the electric double layer capacitor 10-1 that performs charging, so that the DC-DC converter 26 can control the electric double layer capacitor 10-1. The electrical energy stored in -1 is controlled.

This time (a + k / V) from the start of charging
1) When the time has elapsed, the charging of the electric double layer capacitor 10-1 is interrupted, and the same voltage detection and charging operation is repeated for another electric double layer capacitor 10-2 to be charged next. First, the switch elements 12-1 and 14- that were conducting
1 is turned off, and at the same time, the electric double layer capacitor 10-2
A voltage is supplied from the pulse generation circuit 24 only to the control terminals of the switch elements 52-2 and 54-2 connected to the same, and the same charging voltage detection operation is performed. Next, the switch elements 52-2 and 54-2 that have been conducted are turned off, and at the same time, the switch element 1 that is connected to the electric double layer capacitor 10-2.
Only 2-2 and 14-2 are conducted, and the charging operation is repeated.
In this case as well, the charging current is controlled by the current control circuit 22 so as to have a constant value I, and the charging time is set to (a + k / V2). Here, V2 is the charging voltage detection value of the electric double layer capacitor 10-2 detected by the common voltage detecting means 56.

In this way, the common voltage detecting means 5 is provided for one electric double layer capacitor 10-m for charging.
6, detection of charging voltage value Vm and current value I, time (a
+ K / Vm) is charged while sequentially switching the electric double layer capacitors 10-m as shown in the time chart of FIG. The voltage detection and charging operations are shown in the time chart of FIG. 2 until the charging voltage of the electric double layer capacitors 10-m reaches the rated voltage even after all the electric double layer capacitors 10-m are performed. And repeat again. Then, after the charging voltage of the electric double layer capacitor 10-m reaches a value near the rated voltage or less, the set output voltage of the DC-DC converter 26 is fixed to the rated voltage and switched to constant voltage charging. further,
When the charging voltage of the electric double layer capacitor 10-m reaches the rated voltage, the switch elements 12-m and 14-m are made non-conductive and charging is not performed any more.

In the present embodiment, first, the charging voltage of the electric double layer capacitor 10-m for charging is detected, and for a time (a + k / Vm) based on the detected voltage value Vm,
The electric double layer capacitor 10-m is charged with a constant charging current. And, this voltage detection and charging operation,
The electric double layer capacitors 10-1 to 10-n are sequentially switched over and over repeatedly until the charging voltage approaches the rated voltage. Here, the electric double layer capacitor having a high charging voltage is controlled so that the charging time is short, that is, the increase of the charging voltage is small, and the electric double layer capacitor having a low charging voltage is long, that is, the charging is performed. It is controlled so that the increase in voltage is large. Therefore, even if the variation of the charging voltage occurs during charging, the variation of the charging voltage is detected, and the charging is performed by controlling the increase amount of the charging voltage so as to suppress the variation of the charging voltage. 10-1
Each charging voltage of 10-n can be made to converge to a substantially constant value. Therefore, when charging each of the plurality of electric double layer capacitors 10-1 to 10-n connected in series, the charging voltage caused by the variation in the capacitance of the capacitors does not flow through the balance resistor or the bypass circuit. Can be suppressed. Further, it is possible to easily cope with an increase or decrease in the number of electric double layer capacitors to be charged by simply increasing or decreasing the number of switch elements. When detecting the charging voltage, one common voltage detecting means 56 and each of the electric double layer capacitors 10-1 to 10-n are connected to the switch elements 52-1 to 52-n and 54-1 to 54-n. The common voltage detecting means 56 is used to switch the plurality of electric double layer capacitors 10 to detect the charging voltage.
It is possible to detect the charging voltage of each of -1 to 10-n, and it is possible to reduce the cost of the device that performs uniform voltage charging.

In this embodiment, the charging voltage detection value V
The case where the electric double layer capacitor 10-m is charged at a constant charging current for a time (a + k / Vm) based on m has been described. However, the charging voltage becomes shorter as the charging voltage detection value increases. By employing and controlling a characteristic different from the time characteristic, it is possible to suppress variations in the charging voltage of each of the electric double layer capacitors 10-1 to 10-n. Further, in the present embodiment,
The charging current is constant for each of the electric double layer capacitors 10-1 to 10-n, and the charging time is controlled by the switch control circuit 24, whereby the electric double layer capacitor 10 is controlled.
The case of controlling the electric energy stored in each of the -1 to 10-n has been described, but the charging current to each of the electric double layer capacitors 10-1 to 10-n decreases as the detected value of the charging voltage increases. Even with such control, it is possible to suppress variations in the charging voltage of each of the electric double layer capacitors 10-1 to 10-n. Further, both the charging time and the charging current may be controlled according to the charging voltage detection value.

(2) Second Embodiment FIG. 3 is a block diagram showing the configuration of the electric double layer capacitor charging device according to the second embodiment of the present invention. In the present embodiment, the positive electrode terminal 28-1 of the electric double layer capacitor 10-1 is the DC-D as the second charging power source.
It is connected to the positive side terminal 62 of the C converter 66, and the negative side electrode terminal 30-n of the electric double layer capacitor 10-n is DC-.
It is connected to the negative terminal 64 of the DC converter 66,
The DC-DC converter 66 is the DC-DC converter 26.
It is provided in parallel with. The DC voltage is input to the DC-DC converter 66. A diode 74 is provided between the positive electrode terminal 28-1 and a load (not shown) to flow a current from the positive electrode terminal 28-1 only in the load direction. The terminal 76 between the diode 74 and the load and the negative terminal 64 are input to the output voltage detecting means 78. Positive side electrode terminal 28-1 and positive side terminal 6 of the DC-DC converter 66
A current detection resistor 70 is provided on the line between the two, and both terminals thereof are input to the current control circuit 72. The current control circuit 72 operates from the DC-DC converter 66 to the electric double layer capacitors 10-1 to 10 based on the current detection value of the current detection resistor 70 until the voltage detection value of the output voltage detection means 78 reaches a predetermined value. The current flowing to −n is controlled to have a constant value. On the other hand, when the voltage detection value of the output voltage detecting means 78 reaches a predetermined value, the switch (not shown) in the DC-DC converter 66 is made non-conductive to DC-DC.
The supply of charging power from converter 66 is stopped. The predetermined value here is set to a neighborhood value equal to or less than (rated voltage × number of capacitors), for example. Also, the common voltage detection means 56
The output of the DC-DC converter 26 is insulated from the output of the DC-DC converter 66. The other configurations are similar to those of the first embodiment, and therefore will be omitted.

In this embodiment, all the electric double layer capacitors 10-1 to 10-n are charged by the current flowing from the DC-DC converter 66. At the same time, the same voltage detection and DC− as in the first embodiment are performed.
The charging operation by the DC converter 26 is repeated plural times until the charging voltage reaches the rated voltage while sequentially switching each of the electric double layer capacitors 10-1 to 10-n. However, in the present embodiment, the DC-DC converter 26 is operated for the time k / Vm based on the charging voltage detection value Vm of the electric double layer capacitor 10-m for charging.
Charging with a constant charging current by the electric double layer capacitor 10
-M. Here, the DC-DC converter 26
The electric current value flowing from the electric double layer capacitor 10-1 to
It is set in consideration of the variation in capacitance of 10-n, and is set to, for example, 20% or less of the current value flowing from the DC-DC converter 66.

Also in the present embodiment, when each of the plurality of electric double layer capacitors 10-1 to 10-n connected in series is charged, the capacitance of the capacitors does not flow through the balance resistor or the bypass circuit. It is possible to suppress the variation of the charging voltage due to the variation of. In this embodiment, by increasing the value of the current flowing from the DC-DC converter 66 to the electric double layer capacitors 10-1 to 10-n, it is possible to shorten the time required to uniformly charge the capacitors to the rated voltage. . Furthermore, DC-DC
The current value flowing from the converter 26 to the electric double layer capacitor 10-m can be reduced, and the DC-DC converter 26 and the switch elements 12-1 to 12-n, 14-1.
As for 14-n, a small capacity can be used. Therefore, it is possible to further reduce the cost of the device that performs uniform voltage charging.

In the present embodiment as well, as in the first embodiment, by controlling by adopting a characteristic different from the above voltage-time characteristic such that the charging time becomes shorter as the detected value of the charging voltage increases, control is performed. Double layer capacitors 10-1 to 10-1
It is possible to suppress the variation in the charging voltage due to the variation in each capacitance of 0-n. Then, the charging current from the DC-DC converter 26 to each of the electric double layer capacitors 10-1 to 10-n may be controlled to decrease as the detected charging voltage value increases.

In each of the embodiments, the power source for charging is not limited to the DC-DC converter, but may be anything as long as a direct current can be passed through the electric double layer capacitor. The charging method for the electric double layer capacitor is not limited to the constant current charging.

[0028]

As described above, in the present invention, the electric energy stored in the electric double layer capacitor from the first charging power source is controlled based on the charging voltage value of the electric double layer capacitor. It is possible to suppress the variation in the charging voltage due to the variation in the capacitance of the capacitor without passing a current through the balance resistor or the bypass circuit. Therefore, the electric double layer capacitors connected in series can be accurately charged without deterioration.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a charging device for an electric double layer capacitor according to a first exemplary embodiment of the present invention.

FIG. 2 is a first charging operation according to the first embodiment of the present invention.
It is a time chart explaining an example.

FIG. 3 is a block diagram showing a configuration of a charging device for an electric double layer capacitor according to a second exemplary embodiment of the present invention.

[Explanation of symbols]

10-1 to 10-n Electric Double Layer Capacitor, 12-1
~ 12-n, 14-1 to 14-n, 52-1 to 52-
n, 54-1 to 54-n switch element, 20, 70
Current detection resistor, 22, 72 current control circuit, 24 switch control circuit, 26, 66 DC-DC converter,
56 Common voltage detecting means.

Continued front page    (72) Inventor Narumi Hayakawa             2-10-19 Tairiri, Ueda, Nagano Prefecture Ueda Sun             Inside the radio company (72) Inventor Yoshiharu Dou             2-10-19 Tairiri, Ueda, Nagano Prefecture Ueda Sun             Inside the radio company (72) Inventor Setsumoto Setsuo             2-10-19 Tairiri, Ueda, Nagano Prefecture Ueda Sun             Inside the radio company F-term (reference) 5G003 AA01 BA03 CA01 CA11 CC02                       DA07 DA11 GB03

Claims (5)

[Claims] 1. A device for charging a plurality of electric double layer capacitors connected in series, comprising: a first charging power supply for charging the electric double layer capacitors; and a connection with the first charging power supply. The charge switching means for sequentially switching the electric double layer capacitors, the voltage detecting means for detecting each charging voltage of the electric double layer capacitors, and the first voltage based on the charging voltage value of the electric double layer capacitors by the voltage detecting means. A charging control means for controlling the electric energy stored in the electric double layer capacitor from the charging power source, and the charging device for the electric double layer capacitor. 2. The electric double layer capacitor charging device according to claim 1, wherein the second charging device is provided in parallel with the first charging power source and is for charging the entire electric double layer capacitor. An electric double layer capacitor charging device, further comprising a power supply for use. 3. The charging device for the electric double layer capacitor according to claim 1, wherein the charging control means is configured to perform the first charging based on a charging voltage value of the electric double layer capacitor by the voltage detecting means. By controlling the time for connecting the charging power source and the electric double layer capacitor by the charge switching means, the electric energy stored in the electric double layer capacitor from the first charging power source is controlled. Charging device for electric double layer capacitor. 4. The charging device for an electric double layer capacitor according to claim 1, wherein the voltage detecting means includes a common voltage detecting means for detecting a charging voltage of the electric double layer capacitor, An electric double layer capacitor charging device, comprising: a voltage switching unit that sequentially switches and connects the common voltage detecting unit to each of the electric double layer capacitors. 5. A method using the electric double layer capacitor charging device according to claim 1, wherein the voltage detection means detects a charging voltage and the charge control means controls electric energy. The method for charging an electric double layer capacitor is characterized by repeating the above step a plurality of times while sequentially switching each electric double layer capacitor.