JPH07211358A - Capacitor having field effect transistor inside - Google Patents

Abstract

PURPOSE:To provide a capacitor which does not need to outfit an overvoltage preventive circuit, an overcharge-overdischarge preventive circuit, a remaining electric quantity detecting circuit or the like at mounting time. CONSTITUTION:A separator 10 composed of nonwoven fabric is sandwiched by a positive side current collecting electrode 20 and a negative side current collecting electrode 30 composed of aluminium plates. A positive side polarizable electrode 21 and a negative side polarizable electrode 31 composed of activated carbon containing organic electrolyte are formed on inside surfaces of the electrodes 20 and 30. A transistor circuit part 40 containing a thin film transistor is formed on a single surface of the separator 10. A wiring layer and a resistance layer by metallic thin films are formed in the transistor circuit part 40, and the part is used as an electrode of the thin film transistor. An overvoltage preventive circuit, an overcharge-overdischarge preventive circuit, a remaining electric quantity detecting circuit or the like are formed by using this transistor circuit part 40.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention efficiently installs a field effect transistor in a storage device having a field effect transistor therein, and more particularly in a storage battery which can be repeatedly charged and discharged such as a secondary battery and a capacitor. Regarding technology.

[0002]

2. Description of the Related Art Condensers such as secondary batteries and capacitors that can be repeatedly charged and discharged are widely used in industry as main power sources or auxiliary power sources for home appliances and electric vehicles. For example, JP-A-3-107532
The publication discloses a vehicle-mounted capacitor-type power storage device. If these electric storage devices are charged in excess of their permissible electric capacities, they may be overvoltage or overcharged and may be destroyed or deteriorated. Therefore, when these power storage devices are mounted and used in home electric appliances and electric vehicles, it is common to attach and use an overvoltage protection circuit and an overcharge protection circuit. When used in an electric vehicle or the like, it is indispensable to detect the accumulated amount of remaining electricity, and it is necessary to attach and use a detection circuit for detecting the amount of remaining electricity. For example, for lead-acid batteries, such a detection circuit includes a circuit that estimates the amount of remaining electricity from the terminal voltage, a circuit that calculates the amount of remaining electricity by integrating charge and discharge electricity, and the amount of remaining electricity that is calculated from the specific gravity of the electrolyte. An estimating circuit is used.

[0003]

As described above, when a battery is mounted on a home electric appliance, an electric vehicle, or the like, an overvoltage prevention circuit, an overcharge prevention circuit, a remaining electricity amount detection circuit, etc. are externally attached. Need to be used. However, if such an external circuit is further mounted in addition to the capacitor, the overall weight and volume increase, which is not preferable.

Therefore, an object of the present invention is to provide a capacitor which does not require external attachment of an overvoltage prevention circuit, an overcharge prevention circuit, a residual electricity amount detection circuit, etc. at the time of mounting.

[0005]

[Means for Solving the Problems]

(1) The first aspect of the present invention has a positive electrode, a negative electrode, and a separator sandwiched between these electrodes, and has a function of storing a predetermined charge between these electrodes. In the battery, a field effect transistor is formed between the positive electrode or the negative electrode and the separator, and the field effect transistor can control the charging operation of the battery or detect the charging state.

(2) A second aspect of the present invention is the above-mentioned first aspect.
In the electric storage device according to the aspect of (1), a field effect transistor is formed by a thin film transistor formed on one surface of a separator, and a wiring layer and a resistance layer made of a metal thin film are formed on a surface where the thin film transistor is formed, and predetermined wiring is performed. A part of the layer is used as an electrode of a thin film transistor.

(3) A third aspect of the present invention relates to the above-mentioned first aspect.
Alternatively, in the electric storage device according to the second aspect, an overvoltage prevention limiter is formed by the source-drain current path of the field effect transistor and the discharge resistance element connected in series to the electric path, and a positive electrode for storage and a negative electrode The overvoltage prevention limiter and the voltage dividing resistance element are connected in parallel with the electrode so that a predetermined voltage dividing point of the voltage dividing resistance element and the gate of the field effect transistor are connected.

(4) A fourth aspect of the present invention relates to the above-mentioned first aspect.
Alternatively, in the electric storage device according to the second aspect, the inside is filled with an electrolytic solution, and the charging / discharging operation is performed based on a change in the state of the ions of the electrolytic solution. An ion-sensitive transistor is used as the field effect transistor. It is the one that is used.

(5) A fifth aspect of the present invention relates to the above-mentioned fourth aspect.
In the electricity storage device according to the aspect, an overcharge prevention limiter is formed by the source-drain current path of the ion-sensitive field effect transistor and the discharge resistance element connected in series to the current path, and the positive electrode for electricity storage and the negative electrode An overcharge prevention limiter is connected to the side electrode, and the ion sensitive thin film of the ion sensitive field effect transistor is immersed in the electrolytic solution.

(6) The sixth aspect of the present invention is the above-mentioned fourth aspect.
In the capacitor according to the aspect, the wiring connected to the source electrode of the ion-sensitive field effect transistor and the wiring connected to the drain electrode of the ion-sensitive field effect transistor are respectively led to the outside, and the ion-sensitive thin film of the ion-sensitive field effect transistor is electrolyzed. It is soaked in the structure, and is configured to be able to detect the charged state in the electrolytic solution based on the conductive property between both wirings.

[0011]

[Operation] In the present invention, the field effect transistor is formed between the positive electrode or the negative electrode and the separator. In particular, a thin film transistor is formed on one surface of the separator, and a wiring layer and a resistance layer made of a metal thin film are formed on the formation surface of the thin film transistor, and if a part of this wiring layer is used as an electrode of the thin film transistor, an electrode or a separator is formed. The transistor element having an integral structure with can be provided as an integral structure inside the capacitor. If this internal transistor element and wiring layer or resistance layer are used to form an overvoltage prevention circuit, an overcharge prevention circuit, a remaining electricity amount detection circuit, etc., it is necessary to attach a new transistor circuit to the capacitor. Disappears. An overvoltage prevention circuit and an overcharge prevention circuit can be formed by connecting a discharge resistance element to the internally provided transistor element to form a limiter. If an ion-sensitive field effect transistor is used as the internal transistor and the ion-sensitive thin film is soaked in the electrolytic solution, the residual electricity detection circuit can be configured.

[0012]

The present invention will be described below based on illustrated embodiments.

<Embodiment Applied to Electric Double Layer Capacitor Condenser> FIG. 1 is a perspective view of an embodiment to which the present invention is applied to an electric double layer condenser accumulator. The main constituent elements of this battery are an ion-permeable separator 10, a positive side current collecting electrode 20, and a negative side current collecting electrode 30. The positive side polarizable electrode 21 is formed on the inner side surface of the positive side current collecting electrode 20, and the negative side polarizable electrode 31 is formed on the inner side surface of the negative side current collecting electrode 30. Further, the positive side lead 22 is led out from the positive side current collecting electrode 20, and the negative side current collecting electrode 3
From 0, the negative side lead 32 is led to the outside. In this embodiment, a non-woven fabric is used as the ion-permeable separator 10, and the positive side current collecting electrode 20 and the negative side current collecting electrode 30 are used.
An aluminum plate is used as the positive side polarizable electrode 21 and the negative side polarizable electrode 31 are made of activated carbon soaked with an organic electrolytic solution.
Although an aluminum wire is used as the material, it may be replaced with another material having the same function.

The characteristic of this capacitor is that the transistor circuit section 40 is formed on one surface of the separator 10. The transistor circuit section 40 is a circuit including a field effect transistor, and the detailed structure will be described later. The negative electrode 42 and the positive electrode 4 shown in FIG.
Reference numeral 6 is also a part of the constituent elements of the transistor circuit section 40. In FIG. 1, the detailed structure of each component of the transistor circuit section 40 is omitted because the figure becomes complicated. In addition, FIG. 1 shows the transistor circuit unit 4
In order to clearly indicate 0, the state in which the ends of the positive side current collecting electrode 20 and the negative side current collecting electrode 30 are turned over is shown, but in reality, the positive side current collecting electrode 20 and the negative side current collecting electrode 20 are shown. 30 is in a state parallel to the separator 10,
0 has a so-called sandwich structure sandwiched by the positive side current collecting electrode 20 and the negative side current collecting electrode 30. The feature of the present invention resides in that the transistor circuit section 40 is provided between the separator 10 and each electrode layer as described above. In this way, by forming the transistor circuit portion 40 between the layered elements forming the capacitor, it is possible to obtain a structure in which the transistor circuit portion 40 is embedded inside the capacitor. As will be described later, this transistor circuit section 40 is
Since it can be used as an overvoltage prevention circuit or an overcharge prevention circuit, if this capacitor is used, it is not necessary to externally attach these prevention circuits.

FIG. 2 is a side view of the electric storage device shown in FIG. The state where the separator 10 is sandwiched between the positive side current collecting electrode 20 and the negative side current collecting electrode 30 to form a sandwich structure is clearly shown. The positive lead 2
2 and the negative lead 32 are drawn as a wiring diagram for convenience of illustration. The electric storage device having such a structure is a capacitor having a charging / discharging function, and can store and supply charges. That is, when a voltage is applied between the positive side lead 22 and the negative side lead 32 to perform charging, positive and negative ions are exchanged through the ion-permeable separator 10, and the activated carbon of the positive side polarizable electrode 21 is charged with a positive charge. (Negative charge in the electrolytic solution) and negative charge (positive charge in the electrolytic solution) are accumulated in the activated carbon of the negative polarizable electrode 31. When the charges are accumulated in this way, the accumulated charges can be extracted again through the positive side lead 22 and the negative side lead 32 and supplied to an external device that performs a predetermined work. However, in the above charging operation, when an overvoltage of a predetermined allowable value or more is applied between the positive side current collecting electrode 20 and the negative side current collecting electrode 30, there is a problem that each component is deteriorated or destroyed. Occurs. For example, in an electric double layer capacitor, the electrolytic solution causes electrolysis and the electrodes are dissolved. By using the transistor circuit section 40, it is possible to configure a circuit for preventing such an overvoltage from being applied.

Next, a detailed structure of the transistor circuit section 40 will be described with reference to FIGS. 3 and 4. Figure 3
[Fig. 2] is a partially enlarged plan view of an upper surface of a separator 10 of the electric storage pack shown in Fig. 1. The portion where the transistor circuit portion 40 is formed is just enlarged and shown. Also, FIG.
FIG. 4 is a cross-sectional view of the structure shown in FIG. 3 taken along section line 4-4. In addition, in FIG. 3, in order to avoid complication, some components are not shown.

Here, the structure of the transistor circuit portion 40 will be described with reference to FIG. First, an insulating layer 41 made of an amorphous silicon nitride film is formed on the upper surface of the separator 10 made of non-woven fabric. The insulating layer 41 is not shown in the plan view of FIG. 3, but each component constituting the transistor circuit section 40 and the separator 10 are not shown.
It may be formed in a region having a sufficient width to insulate between and. On the upper surface of this insulating layer 41,
Negative electrode 42 (the left end in the figure functions as a source electrode)
And a drain electrode 43 are formed. These electrodes may be made of a metal such as aluminum. A semiconductor channel layer 44 is formed between these electrodes, and a gate insulating layer 45 is formed thereon. Here, the semiconductor channel layer 44 is made of amorphous silicon, and the gate insulating layer 45 is made of an amorphous silicon nitride film. On the other hand, the positive electrode 46 is formed at the left end of FIG. The positive electrode 46 has a U-shaped cross section, and the separator 1
The end portion of 0 is shaped so as to wrap around from the upper surface to the lower surface.

Further, a metal thin film 47 is formed on these. The planar pattern of the metal thin film 47 is clearly shown in the plan view of FIG. Here, for convenience of explanation, this metal thin film 47 is referred to as 5a of 47a to 47e.
It is shown in two parts. In FIG. 3, the metal thin film 47a is a region that should be called a main trunk that vertically extends in the center, the metal thin film 47b is a trunk that similarly vertically extends on the left side thereof, and the metal thin film 47c is continuous to the upper portion of the metal thin film 47b. It is a short trunk. The metal thin films 47d and 47e are branch portions extending rightward from both end points of the metal thin film 47c. In FIG. 4, these metal thin films 47a-4
Of 7e, only 47a, 47d, and 47e appear as a cross section. Since the metal thin films 47b and 47c are located at the back of them, they are not shown in FIG. This metal thin film 4
Since 7 is used as a wiring layer and a resistance element as described later, a predetermined material (for example, chrome) is used so as to have an electric resistance suitable for performing the functions of the wiring layer and the resistance element. To the thickness of.

In such a structure, as shown in FIG.
It will be appreciated that a thin film transistor (field effect transistor) 100 is formed. That is, the drain electrode 43 and the source electrode (the left end portion of the negative electrode 42) are formed on both sides of the semiconductor channel layer 44, and further above the semiconductor channel layer 44, the gate insulating layer 4 is formed.
A gate electrode (metal thin film 47d) is formed via the gate electrode 5. In such a thin film transistor 100, the semiconductor channel layer 4 is changed by the voltage applied to the gate electrode 47d.
It is possible to control ON / OFF of the channel formed in No. 4. That is, in the case of an enhancement type transistor, when the voltage of the gate electrode 47d exceeds a predetermined threshold value, the channel of the transistor turns on. In the plan view of FIG. 3, the formation region of the thin film transistor 100 is indicated by a broken line, and the rough positions of the source electrode S, the gate electrode G, and the drain electrode D are indicated by symbols S, G, and D.

Finally, an insulating protective film 48 made of an amorphous silicon nitride film is formed so as to cover these layers. The area occupied by the plane pattern of the insulating protective film 48 is shown by a dashed line in FIG. That is, the insulating protective film 48 is formed in a region that covers almost the entire surface of the transistor circuit portion 40. In the perspective view of FIG. 1, the transistor circuit portion 40 and the negative side current collecting electrode 30 are formed.
And will be electrically isolated. However, as shown in FIGS. 3 and 4, a portion of the negative electrode 42 is exposed without being covered by the insulating protective film 48, and this exposed portion is the negative current collecting electrode 30. Will be in contact with. Therefore, in the transistor circuit portion 40, only the negative electrode 42 is electrically connected to the negative collector electrode 30. Similarly, the positive electrode 46, which wraps around the lower surface of the separator 10, comes into contact with the positive current collecting electrode 20, and is electrically connected.

Although the structure of this embodiment has been described in detail above, the capacitor having such a structure has the thin film transistor 100 therein, and the thin film transistor 100 provided therein already causes the overvoltage. The prevention circuit is formed. To explain this,
FIG. 5 shows an equivalent circuit diagram of this capacitor. In this equivalent circuit, the capacitive element shown in the lower part of the figure is the positive side current collecting electrode 2
0 and a negative side current collecting electrode 30. As described above, the positive electrode 46 is electrically connected to the positive collector electrode 20, and the positive lead 22 is also connected to the positive electrode 46. Similarly, the negative side electrode 42 is electrically connected to the negative side current collecting electrode 30, and the negative side lead 32 is also connected. Next, let's look at the connection relationship of the thin film transistors 100. As shown in FIG. 4, a metal thin film 47e is connected to the source electrode (negative side electrode 42) of the thin film transistor 100. Here, considering that the plane pattern of the metal thin film 47 is as shown in FIG.
Metal thin films 47c and 47b that function as a resistance element connected between (D) and the positive electrode 46 and also function as a resistance element in series are provided between the negative electrode 42 and the positive electrode 46. You can see that they are connected.

Now, let us consider the charging operation of the equivalent circuit shown in FIG. In this circuit, when charges are stored in the capacitor composed of the positive side current collecting electrode 20 and the negative side current collecting electrode 30, a predetermined charging voltage Vc may be applied between the positive side lead 22 and the negative side lead 32. At this time, the charging voltage Vc is applied to the capacitors and also to the series resistors 47b and 47c. Here, the gate voltage Vg of the thin film transistor 100
Is the charging voltage Vc divided by the two resistance elements 47b and 47c. Then, this gate voltage V
When g exceeds a predetermined threshold value, the thin film transistor 10
When 0 is ON, the source S / drain D becomes conductive, and a current flows between the positive side lead 22 / negative side lead 32 through the resistance element 47a. Therefore, the resistance element 47
If the voltage dividing ratio by b and 47c is set appropriately, when the charging voltage Vc exceeds a predetermined allowable voltage value, the thin film transistor 100 is turned on, a current is passed through the resistance element 47a, and an overvoltage is not applied to the capacitor. It is possible to do so.

In short, the resistance element 47a functions as a discharge resistance element connected in series to the current path between the source and drain of the thin film transistor 100, and the resistance element 47a.
The thin film transistor 100 and the thin film transistor 100 form an overvoltage prevention limiter. In addition, the resistance element 47
b and 47c function as a voltage dividing resistance element, and the predetermined voltage dividing point is connected to the gate electrode G of the thin film transistor 100. When the charging voltage Vc gradually increases, the voltage at the voltage dividing point, that is, the gate voltage V
g also gradually increases. Therefore, if the voltage dividing ratio of the voltage dividing resistance element is set so that the gate voltage Vg becomes the threshold value of the thin film transistor 100 when the charging voltage Vc reaches the allowable voltage value for the capacitor, the charging voltage Vc is set. When the voltage exceeds the allowable voltage value, the transistor is turned on, current flows through the discharge resistance element 47a, and excess power is consumed.

As described above, the electric storage pack according to the present embodiment is already in the state in which the overvoltage protection circuit is incorporated. Here, the thin film transistor 100 is turned off.
Resistance element 47 for source-drain resistance and voltage division
If the resistances of b and 47c are set to be high, the current flowing through the discharging resistance element 47a and the voltage dividing resistance elements 47b and 47c is very small as long as the charging voltage Vc does not exceed the allowable voltage value. Since it is minute, the waste of the electric power stored in the capacitor does not pose a practical problem.

<Example of application to lead-acid battery type battery>
FIG. 6 is a perspective view of an embodiment in which the present invention is applied to a lead storage battery type electric storage device. The main components of this battery are the battery case 50, the separator 60, the positive electrode 70, and the negative electrode 80. The electrolytic solution 51 is filled in the battery case 50, and the separator 60 is connected to the positive electrode 70 and the negative electrode 8.
A sandwich structure is formed by sandwiching the sandwich structure with 0, and the sandwich structure is put in a battery case 50 and immersed in an electrolytic solution 51. In this embodiment, in a resin battery case 50,
The electrolytic solution 51 is filled with dilute sulfuric acid, the positive electrode 70 is a lead oxide plate, and the negative electrode 80 is a lead plate. A nonwoven fabric is used as the separator 60. Of course, these may be replaced with another material having the same function.

The feature of this capacitor is that the transistor circuit section 90 is formed on one surface of the separator 60. The transistor circuit section 90 is a circuit including an ion-sensitive field effect transistor, and the detailed structure will be described later. Similar to the above-described embodiment, by forming the transistor circuit unit 90 between the layered elements forming the electric storage device, the transistor circuit unit 90 is formed inside the electric storage device.
It is possible to obtain a structure in which is embedded. As will be described later, since the transistor circuit section 90 can be used as an overcharge prevention circuit or a remaining electricity amount detection circuit,
With this capacitor, it is not necessary to attach these circuits afterwards.

Next, a detailed structure of the transistor circuit section 90 will be described with reference to FIGS. 7 and 8. Figure 7
FIG. 7 is a partially enlarged plan view of one side of a separator 60 of the electric storage pack shown in FIG. 6. The portion where the transistor circuit portion 90 is formed is just enlarged and shown. Also, FIG.
FIG. 8 is a sectional view of the structure shown in FIG. 7 taken along section line 8-8. In addition, in FIG. 7, some components are not shown in order to avoid complication.

Here, the structure of the transistor circuit portion 90 will be described with reference to FIG. First, an insulating layer 61 made of an amorphous silicon nitride film is formed on the upper surface of the separator 60 made of non-woven fabric. The insulating layer 61 is not shown in the plan view of FIG. 7, but each component constituting the transistor circuit section 90 and the separator 60.
It may be formed in a region having a sufficient width to insulate between and. On the upper surface of the insulating layer 61,
An electrode 62 having a pattern as shown in the plan view of FIG.
a, 62b, 62c are formed. These electrodes may be made of a metal such as aluminum. In the sectional view of FIG. 8, among these electrodes, the electrode 62
b and electrode 62c (only part) are visible. A semiconductor channel layer 63 is formed between the electrodes 62b and 62c, and an ion sensitive thin film 64 is formed thereon. Here, the semiconductor channel layer 63 is made of amorphous silicon, and the ion sensitive thin film 64 is made of a silicon oxide thin film or a silicon nitride thin film. Further, the discharge resistance element 65 is provided at the left end of the electrode 62b.
Is covered from above. The discharge resistance element 65 is
As shown in FIG. 7, it is a resistance element connected between the electrode 62a and the electrode 62b, and has a predetermined material (for example, chrome) so as to have an electric resistance suitable for performing a function as a discharge resistance. ) Is used to form the film with a predetermined thickness. Finally, an insulating protective film 66 made of an amorphous silicon nitride film is formed so as to cover these layers. The area occupied by the plane pattern of the insulating protective film 66 is shown by a dashed line in FIG. That is, although the insulating protective film 66 is formed in a region that covers almost the entire surface of the transistor circuit portion 90, the ion-sensitive thin film 6 is formed.
An opening window is partially formed so that a part of 4 is exposed. The upper ends of the electrodes 62a, 62b, 62c are
It is exposed from the insulating protective film 66 so that wiring can be performed later.

In such a structure, as shown in FIG.
An ion sensitive thin film transistor (field effect transistor) 200 is formed. That is, the drain electrode (the left end portion of the electrode 62b) and the source electrode (electrode 62c) are formed on both sides of the semiconductor channel layer 63, and the ion sensitive thin film 64 is formed above the semiconductor channel layer 63. Are formed. In such an ion-sensitive thin film transistor 200, depending on the ion concentration value of the liquid touching the ion-sensitive thin film 64, the semiconductor channel layer 6
ON / OFF of the channel formed in 3 can be controlled. For example, when a silicon oxide thin film is used as the ion sensitive thin film 64, ON / OFF operation sensitive to the hydrogen ion concentration (pH value) becomes possible, and the pH value of the solution touching the ion sensitive thin film 64 becomes a predetermined threshold value. When the temperature becomes below (in other words, when the solution becomes more acidic than a certain level), the transistor is turned on. In the plan view of FIG. 7, the formation region of the thin film transistor 200 is indicated by a broken line, and the rough positions of the source electrode S, the gate electrode G, and the drain electrode D are indicated by symbols S, G, and D.

The structure of this embodiment has been described above in detail. The capacitor having such a structure has the ion-sensitive thin film transistor 200 therein, and the thin film transistor 200 provided therein is used. Thus, it is possible to form an overcharge prevention circuit or a remaining electricity amount detection circuit.

First, the case of forming an overcharge prevention circuit will be described. In this case, the electrode 62a shown in FIG. 7 may be connected to the positive electrode 70 and the electrode 62c may be connected to the negative electrode 80 (the electrode 62b may not be used). FIG. 9 shows an equivalent circuit of this capacitor when such connection is made. The portion shown by the broken line in the figure is the battery case 50,
The hatched portion is the portion filled with the electrolytic solution 51. The electrolytic solution 51 is used for the thin film transistor 2
The ion sensitive thin film 64 of No. 00 is filled to such a height that it is immersed. Of course, a sandwich structure including the separator 60, the positive electrode 70, and the negative electrode 80 is immersed in the electrolytic solution 51. As aforementioned,
When the electrode 62a is connected to the positive electrode 70 and the electrode 62c is connected to the negative electrode 80, a discharge resistance element 65 is provided between the positive electrode 70 and the negative electrode 80 as shown in FIG. The thin film transistor 200 and the thin film transistor 200 are connected in series.

Now, let us consider the charging / discharging operation of the equivalent circuit shown in FIG. In this circuit, in order to store electric power in the electrolytic solution 51, a predetermined charging voltage may be applied between the positive electrode 70 and the negative electrode 80. When such a charging operation is performed, in the electrolytic solution 51, a chemical reaction of Pb + PbO ₂ + 2H ₂ SO ₄ (2H ⁺ + SO ₄ ⁻ ) ← 2PbSO ₄ + 2H ₂ 0 proceeds, and the concentration of dilute sulfuric acid in the electrolytic solution 51 ( That is, the hydrogen ion concentration) increases. On the contrary, when using the electric power stored in this battery, the positive electrode 7
It suffices to supply electric power from 0 and the negative electrode 80 to external equipment. When such a discharging operation is performed, the electrolytic solution 5
In 1, the chemical reaction of Pb + PbO ₂ + 2H ₂ SO ₄ (2H ⁺ + SO ₄ ⁻ ) → 2PbSO ₄ + 2H ₂ 0 in the opposite direction to that described above proceeds, and the diluted sulfuric acid concentration in the electrolyte solution 51 (that is, the hydrogen ion concentration). ) Is reduced.

Now, assuming that an enhancement type transistor is used as the thin film transistor 200, when the hydrogen ion concentration in the electrolytic solution 51 exceeds a predetermined threshold value, the potential of the ion sensitive thin film 64 also exceeds a predetermined threshold value. The transistor is turned on. Conversely, electrolyte 5
When the hydrogen ion concentration in 1 becomes less than a predetermined threshold value,
The potential of the ion sensitive thin film 64 also becomes less than or equal to a predetermined threshold value, and the transistor is turned off. ON like this
An overcharge prevention circuit can be realized by the / OFF operation. That is, if the thin film transistor 200 is set to be turned on by the hydrogen ion concentration value of the electrolytic solution 51 at this time when the capacitor is overcharged, the source S / drain D between the thin film transistor 200 is It conducts, a current flows through the resistance element 65 for discharge, and excess power is consumed. This mechanism is the same as the above-mentioned embodiment. When the overcharged state returns to the normal charged state due to the discharge by the discharge resistance element 65, the hydrogen ion concentration value in the electrolytic solution 51 decreases, the thin film transistor 200 turns off, and the discharge by the discharge resistance element 65 occurs there. It will be canceled.

Next, the case of forming the remaining electricity amount detecting circuit will be described. In this case, the electrode 62c shown in FIG.
Is connected to the negative electrode 80, the electrode 62b is used as a detection terminal, and the remaining electricity amount is detected based on the electrical state of the electrode 62b and the electrode 62c (the electrode 62a is not used. May be). FIG. 10 shows an equivalent circuit of this capacitor when such connection is made.
The portion shown by the broken line in the figure is the battery case 50, and the hatched portion is the portion filled with the electrolytic solution 51.
After all, the electrolytic solution 51 is filled to such a height that the ion sensitive thin film 64 of the thin film transistor 200 is immersed therein.

As described above, the thin film transistor 200
Is ON / ON based on the hydrogen ion concentration value in the electrolytic solution 51.
Turns off. Therefore, the electrodes 62b and 62c
The state of charge can be detected based on the resistance value between and.
For example, if the thin film transistor 200 is turned on when the amount of stored electricity in the electrolytic solution 51 is equal to or higher than a predetermined reference value, and is turned off when the amount of stored electricity is less than the predetermined reference value, the electrode 62b is set. The rapid increase in resistance between the electrode and the electrode 62c causes the thin film transistor 200
Can be detected, and it can be recognized that the amount of electricity stored in the electrolytic solution 51 has fallen below a predetermined reference value. As described above, the method of directly detecting the electrical state in the electrolytic solution 51 is the conventional method of estimating the remaining electricity amount from the terminal voltage, or the remaining electricity amount is calculated by integrating the charge / discharge electricity amount of the lead storage battery. Compared with the conventional method, there is an advantage that the residual electricity amount can be accurately detected.

As described above, in the capacitor according to this embodiment,
By forming a predetermined wiring for the electrodes 62a, 62b, 62c, it is possible to form an overcharge prevention circuit or a remaining electricity amount detection circuit, so that it is not necessary to attach these circuits externally as in the conventional case. .

Although the present invention has been described above based on the illustrated embodiments, the present invention is not limited to these embodiments and can be implemented in various modes other than this. For example, in the embodiment applied to the above-mentioned capacitor-type power storage device, the example of the power storage device including a single capacitor is mentioned.
The present invention can also be applied to a storage battery formed by connecting a plurality of capacitors in series or in parallel. In this case, if a field effect transistor is provided for each individual capacitor, overvoltage can be prevented for each capacitor. Similarly, the lead-acid battery type embodiment described above can be applied to a battery having a plurality of cells. Further, regarding the lead storage battery type electric storage device, in the above-mentioned embodiment, although the ion-sensitive field effect transistor is used, as in the embodiment applied to the capacitor type electric storage device,
ON / OFF control may be performed by a voltage dividing resistance element using a normal field effect transistor. Further, the present invention is not limited to the electric storage device using the electric double layer capacitor or the lead storage battery, but may be an electrolytic capacitor, a lithium secondary battery, or the like.
The same can be applied to a capacitor having another separator.

[0038]

As described above, according to the capacitor according to the present invention, a field effect transistor is formed between the electrode layer and the separator, and the field effect transistor controls the charging operation of the capacitor or detects the charging state. Therefore, it is not necessary to externally attach an overvoltage prevention circuit, an overcharge prevention circuit, a remaining electricity amount detection circuit, etc. at the time of mounting.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment in which the present invention is applied to a capacitor type power storage device.

FIG. 2 is a side view of the electric storage pack shown in FIG.

FIG. 3 is a partially enlarged plan view of an upper surface of a separator 10 of the electric storage pack shown in FIG.

FIG. 4 is a sectional view of the structure shown in FIG. 3 taken along section line 4-4.

5 is an equivalent circuit diagram of the capacitor shown in FIG.

FIG. 6 is a perspective view of an embodiment in which the present invention is applied to a lead storage battery type electric storage device.

7 is a partially enlarged plan view of one side of a separator 60 of the electric storage pack shown in FIG.

FIG. 8 is a cross-sectional view of the structure shown in FIG. 7 taken along section line 8-8.

9 is an equivalent circuit diagram in the case where an overcharge prevention circuit is formed in the electric storage pack shown in FIG.

10 is an equivalent circuit diagram in the case where a residual electricity amount detection circuit is formed in the electric storage device shown in FIG.

[Explanation of symbols]

 10 ... Separator 20 ... Positive side current collecting electrode 21 ... Positive side polarizable electrode 22 ... Positive side lead 30 ... Negative side current collecting electrode 31 ... Negative side polarizable electrode 32 ... Negative side lead 40 ... Transistor circuit part 41 ... Insulating layer 42 ... Negative side electrode 43 ... Drain electrode 44 ... Semiconductor channel layer 45 ... Gate insulating layer 46 ... Positive side electrode 47, 47a to 47e ... Metal thin film 48 ... Insulation protective film 50 ... Battery case 51 ... Electrolyte 60 ... Separator 61 ... Insulating layer 62a, 62b, 62c ... Electrode 63 ... Semiconductor channel layer 64 ... Ion sensitive thin film 65 ... Discharge resistance element 66 ... Insulating protective film 70 ... Positive electrode 80 ... Negative electrode 90 ... Transistor circuit part 100 ... Thin film transistor 200 ... Ion-sensitive thin film transistor

Claims (6)

[Claims] 1. A capacitor having a positive side electrode, a negative side electrode, and a separator sandwiched between these electrodes, and having a function of storing a predetermined charge between the both electrodes, wherein the positive side electrode Alternatively, a field-effect transistor is formed between the negative electrode and the separator, and the field-effect transistor is capable of controlling the charging operation or detecting the charging state of the capacitor. An internal battery. 2. The electric storage device according to claim 1, wherein the thin film transistor formed on one surface of the separator constitutes a field effect transistor, and a wiring layer and a resistance layer made of a metal thin film are formed on a surface where the thin film transistor is formed. And a part of the wiring layer is used as an electrode of the thin film transistor, wherein the field effect transistor is internally provided. 3. The capacitor according to claim 1, wherein an overvoltage prevention limiter is formed by a source-drain current path of the field effect transistor and a discharge resistance element connected in series to the current path. Between the positive electrode and the negative electrode, the overvoltage prevention limiter and the voltage dividing resistance element are connected in parallel, and a predetermined voltage dividing point of the voltage dividing resistance element and the gate of the field effect transistor are connected. An electric storage device having a field effect transistor therein. 4. The electric storage device according to claim 1, wherein the inside of the electric storage device is filled with an electrolytic solution, and charge / discharge operation is performed based on a change in the state of ions of the electrolytic solution. A capacitor having an internal field effect transistor, characterized in that an ion-sensitive transistor is used. 5. The capacitor according to claim 4, wherein an overcharge prevention limiter is formed by the source-drain current path of the ion-sensitive field effect transistor and a discharge resistance element connected in series to the current path. Between the positive electrode and the negative electrode for use, the overcharge prevention limiter is connected,
A capacitor having an internal field effect transistor, wherein the ion sensitive thin film of the ion sensitive field effect transistor is immersed in an electrolytic solution. 6. The storage device according to claim 4, wherein the wiring connected to the source electrode and the wiring connected to the drain electrode of the ion-sensitive field effect transistor are led out to the outside, respectively, and the ion-sensitive field effect is obtained. The ion-sensitive thin film of the transistor is soaked in an electrolytic solution, and a field effect transistor characterized by being configured to be able to detect the storage state in the electrolytic solution based on the conductive property between the both wirings is provided internally. Battery.