JP7066974B2 - EC element drive system - Google Patents

Description

The present invention relates to an EC element drive system.

An electrochromic element (hereinafter referred to as an EC element) that performs color change by electric power is known. When driving this EC element, the constant voltage method is generally used because the drive voltage easily exceeds the limit voltage of the EC element in the constant current method.
However, in the constant voltage method, due to the electrical characteristics of the EC element at the initial stage of driving, an inrush current of a magnitude exceeding the allowable value of the characteristics of the EC element is generated, so that an excessive load current acts on the power supply, resulting in energy. There is a problem that the efficiency is deteriorated and the life of the EC element is shortened.

In order to solve the above-mentioned problems, the inrush current is controlled by detecting the current on the primary side of the power supply module, which is separated into the primary side and the secondary side by a transformer for increasing the voltage. A technique for preventing the occurrence is disclosed (see, for example, "Patent Document 1").
However, the above-mentioned technique requires a current detection control circuit, which increases the number of parts, increases the cost, and hinders the miniaturization of the device.

An object of the present invention is to provide an EC element drive system capable of preventing the generation of inrush current to save energy and extending the life of the EC element.

The invention according to claim 1 is an EC element drive system for driving an EC element with a constant voltage, which includes a power supply, a constant voltage power supply unit that outputs the power supplied from the power supply as a constant voltage, and the constant voltage power supply unit. It has a current suppression unit that suppresses the initial current applied to the EC element when the EC element is driven by receiving a voltage from the current device, and a control unit that controls the operation of the current suppression unit. The control unit has the control unit. The current is suppressed from the constant voltage power supply unit so that the initial current does not exceed the characteristic permissible value, which is the limit value at which the life of the EC element is shortened and the energy efficiency is deteriorated, which is determined for each EC element. It is characterized by controlling the voltage value supplied to the unit.

According to the present invention, an EC element drive system capable of preventing an inrush current from acting as an initial current on an EC element, saving energy, and extending the life of the EC element. Can be provided.

It is a block diagram of the EC element drive system to which one Embodiment of this invention is applied. It is a schematic diagram explaining the structure of the EC element used in one Embodiment of this invention. It is a diagram which shows the relationship between the driving time of an EC element and a battery voltage in one Embodiment of this invention. It is a diagram which shows the phenomenon that the battery voltage drops when the inrush current is generated in one Embodiment of this invention.

FIG. 1 shows a block diagram of an EC element drive system to which one embodiment of the present invention is applied. In the figure, the EC element drive system 1 for driving the EC element 2 has a power supply 3, a system power supply unit 4, a constant voltage power supply unit 5, a current suppression unit 6, an EC element drive circuit 7, a control unit 8, and the like. There is.

FIG. 2 is a schematic view showing the configuration of the EC element 2. As shown in the figure, the EC element 2 includes a first electrode 11 provided between the pair of substrates 9 and 10, and a second electrode 12 arranged to face the first electrode 11 at a predetermined interval. It has at least an electrolyte 13 arranged between the electrodes 11 and 12, and has an absorption band in the visible region on the surface of one of the electrodes in an oxidized state.
In the configuration shown in FIG. 2, an electrochromic compound or an electrochromic composition containing an electrochromic compound or an electrochromic composition having an absorption band in the visible region is formed on the surface of the first electrode 11 in an oxidized state, and the second electrode 12 is formed. An electrochromic layer 15 containing an electrochromic compound or an electrochromic composition having an absorption band in the visible region in a reduced state is formed on the surface. Reference numerals 16 and 17 indicate a sealing member for sealing the electrolyte 13 and the respective electrochromic layers 14 and 15.

When a charge is applied to the first electrode 11 and the second electrode 12 with respect to the above-mentioned EC element 2, the electrochromic layers 14 and 15 undergo a redox reaction to control coloring and decolorization. By injecting electric charge from the electrochromic layer 14 which is an oxidation electrode at the time of coloring, and by injecting electric charge from the electrochromic layer 15 which is a reducing electrode in order to transfer the electric charge in the EC element 2 at the time of decoloring. The color is developed and extinguished by the rapid charge transfer in the EC element 2. Therefore, power is consumed not only at the time of coloring but also at the time of decoloring.
In the EC element 2, the movement speed of the electric charge, that is, the reaction speed increases according to the magnitude of the electric charge applied to the first electrode 11 and the second electrode 12, but the characteristic permissible value determined for each EC element is set. When a current exceeding the current rate is applied, the molecular structure of the redox materials used for the electrochromic layers 14 and 15 deteriorates, so that the life of the EC element is shortened and the energy efficiency is deteriorated, resulting in an increase in cost. Here, charge injection is performed from the oxide electrode during coloring, and charge injection is performed from the reduction electrode during decolorization. However, this does not apply depending on the configuration of the EC element, and the charge injection direction of the electrode may be reversed. In some cases.

Further, due to the principle of the EC element 2, that is, a sudden charge transfer may occur when the electric charge is applied to the first electrode 11 and the second electrode 12, so that an inrush current is generated at the time of the decolorizing drive at the time of the initial current action. The magnitude of this inrush current varies depending on the configuration and size of the EC element, but in the EC element 2 shown in the present embodiment, the element size is 30 × 30 mm, and an inrush current of 30 to 100 mA is observed. FIG. 3 shows an example of a sudden voltage drop in the power supply 3 due to this inrush current.

As the power source 3, any DC power source, AC power source, battery, or the like may be used, but when an AC power source is used, it is necessary to use an AC / DC converter together to convert AC to DC. be. In this embodiment, an example using a battery will be described.
The system power supply unit 4 drives the control unit 8 with the electric power supplied from the power supply 3.
The constant voltage power supply unit 5 receives the electric power supplied from the power supply 3 and outputs a constant voltage to the current suppression unit 6. The constant voltage power supply unit 5 is a power supply for driving the EC element 2, and specific configurations thereof include a regulator, a DCDC converter, and the like.
The EC drive circuit 7 supplies the electric power output from the current suppression unit 6 to the first electrode 11 and the second electrode 12 to drive the EC element 2.
As the control unit 8, a well-known microcomputer having a CPU, ROM, RAM, I / O, etc. (not shown) is used.

Next, the current suppression section 6, which is a feature section of the present invention, will be described. The current suppression unit 6 functions to suppress the initial current applied to the EC element 2 when the EC element 2 is driven. Specific configurations of the current suppression unit 6 include semiconductor devices capable of limiting the current value, such as a constant current diode (CRD) or a field effect transistor (FET). First, a case where a constant current diode is used as the current suppression unit 6 will be described. In this case, as the constant current diode to be selected, a diode having a current value whose output pinch-off current value does not exceed the characteristic allowable value of the EC element 2 is selected.

When a constant current diode is used as the current suppression unit 6, control is performed so that the pinch-off current value, which is a constant current, is output from the current suppression unit 6 and does not exceed the maximum working voltage value of the constant current diode. The unit 8 controls the voltage value supplied from the constant voltage power supply unit 5 to the current suppression unit 6. Further, the voltage value controlled at this time is controlled so that the power consumption of the constant current diode is within the rated power of the constant current diode.

With the above configuration, the control unit 8 is supplied from the constant voltage power supply unit 5 to the current suppression unit 6 so that the initial current value applied to the EC element 2 does not exceed the characteristic allowable value of the EC element 2. The operation of the current suppression unit 6 is controlled by controlling the voltage value. As a result, it is possible to prevent an inrush current from being generated as an initial current for the EC element 2, shortening the life of the EC element 2 and preventing deterioration of energy efficiency, thereby saving energy. It is possible to provide an EC element drive system 1 capable of extending the life of the EC element 2 at the same time.

Next, a case where a field effect transistor is used as the current suppression unit 6 will be described. When a field effect transistor is used as the current suppression unit 6, the control unit so that the drain current value, which is a constant current output from the current suppression unit 6, does not exceed the characteristic allowable value of the EC element 2. 8 controls the voltage value supplied from the constant voltage power supply unit 5 to the current suppression unit 6, that is, the gate of the field effect transistor.

With this configuration, as in the case where a constant current diode is used as the current suppression unit 6, it is prevented that an inrush current is generated as an initial current for the EC element 2, the life of the EC element 2 is shortened, and the energy efficiency is reduced. It is possible to provide an EC element drive system 1 capable of preventing the deterioration of the EC element and extending the life of the EC element 2 while saving energy.
Further, since the drain current value to be output can be changed by controlling the voltage value supplied to the gate, if it is within the load range of the EC element to be used, the EC element drive system 1 is configured and then the EC is configured. Even when the element 2 is changed, the constant current control can be performed without changing the current suppression unit 6.

In the above-described embodiment, the EC element drive system 1 using a battery as the power source 3 has been described. As described above, the EC element drive system using a battery as the power source 3 can be applied to a small portable device, for example, a wearable device. Since wearable devices are required to be small and lightweight, small capacity batteries are generally used. For example, the capacity of a small secondary battery having a diameter of 4 mm and a length of about 20 mm is about 20 mAh, and when an EC element is driven, if an inrush current exceeding 30 mA as shown in FIG. 3 flows, the discharge characteristics are significantly affected. ..
As shown in FIG. 3, under condition 1 in which there is no current suppression circuit which is the current suppression unit 6 shown in the above embodiment, assuming that the battery voltage is 3.6 V as the lower limit value when the system is driven, it takes about 2.5 hours. It turned out that the battery voltage dropped. However, when the current suppression unit 6 of the present invention was mounted, the condition 2 was satisfied, and it was confirmed that the voltage drop was extended to about 5.0 hours. This indicates that the battery life has been extended by improving the discharge characteristics of the battery.

FIG. 4 shows a phenomenon in which the battery voltage drops when an inrush current is generated when the EC element is driven. In FIG. 4, it was confirmed that a voltage drop of about 0.08 V occurs under condition 1 having no current suppression circuit. However, under condition 2 provided with the current suppression circuit, it was confirmed that the occurrence of voltage drop is prevented by limiting the current value under the condition that the performance such as the reaction speed of the EC element is satisfied. The voltage drop value in FIG. 4 changes depending on the configuration and size of the EC element.

As described above, according to the EC element drive system 1 of the present invention, since the battery can be used as the power source 3, it can be mounted not only on a fixed device but also on a movable device, and the range of use is expanded. can do. Further, by using a small battery as the power source 3, the EC element drive system of the present invention can be mounted on a small portable device, for example, a wearable device, and the life of the battery can be extended by energy saving while extending the life of the EC element. It is possible to provide a small portable device capable of providing a small portable device.

In the above-described embodiment, the EC element drive system 1 for driving only one EC element 2 has been described, but the configuration may be such that two or more EC elements are driven. In this case, the control unit 8 controls the voltage value supplied from the constant voltage power supply unit 5 to the current suppression unit 6 in response to the load of all the EC elements. The load of all EC elements at this time changes depending on the configuration and type of each EC element, the connection state of each EC element, and the like.

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment, and unless otherwise specified in the above description, the present invention described in the claims. Various modifications and changes are possible within the scope of the purpose. The effects described in the embodiments of the present invention merely exemplify the most preferable effects resulting from the present invention, and the effects according to the present invention are limited to those described in the embodiments of the present invention. is not.

1 EC element drive system 2 EC element 3 Power supply 6 Current suppression unit 8 Control unit

Japanese Unexamined Patent Publication No. 2007-225693

Claims (7)

An EC element drive system that drives an EC element at a constant voltage.
A power supply , a constant voltage power supply unit that outputs the power supplied from the power supply as a constant voltage, and a voltage from the constant voltage power supply unit are received to suppress the initial current applied to the EC element when the EC element is driven. It has a current suppression unit and a control unit that controls the operation of the current suppression unit.
The control unit has the constant voltage so that the initial current does not exceed the characteristic permissible value, which is the limit value at which the life of the EC element is shortened and the energy efficiency is deteriorated, which is determined for each EC element. An EC element drive system characterized by controlling a voltage value supplied from a power supply unit to the current suppression unit. In the EC element drive system according to claim 1,
The current suppression unit has a constant current diode, and the control unit so that a pinch-off current value which is a constant current is output from the current suppression unit and does not exceed the maximum working voltage value of the constant current diode. Is an EC element drive system characterized in that the voltage value supplied from the constant voltage power supply unit to the current suppression unit is controlled . In the EC element drive system according to claim 2 ,
An EC element drive system characterized in that the voltage value controlled by the control unit is controlled so that the power consumption of the constant current diode is within the rated power of the constant current diode . In the EC element drive system according to claim 1 ,
The current suppression unit has a field effect transistor provided with a gate, and the control unit is a constant voltage power supply so that the drain current value, which is a constant current output from the current suppression unit, does not exceed the characteristic permissible value. An EC element drive system characterized by controlling a voltage value supplied from a unit to the gate . In the EC element drive system according to claim 4 ,
The EC element drive system is characterized in that the current suppression unit can change the value of the initial current . In the EC element drive system according to any one of claims 1 to 5 .
An EC element drive system characterized in that the power source is a battery . In the EC element drive system according to claim 6,
An EC element drive system characterized by being able to be mounted on a small mobile device.

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