JPH1126321A - Electric double layer capacitor - Google Patents

Abstract

(57) [Problem] To provide a large-capacity electric double layer capacitor having high withstand voltage and low equivalent series resistance. A plurality of capacitor elements, each of which has been swaged and has a lead surface formed on an upper surface and a lower surface, are connected in series and housed in a metal case.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an electric double layer capacitor.

[0002]

2. Description of the Related Art An electric double layer capacitor is made by kneading, for example, activated carbon, carbon, and polytetrafluoroethylene (PTFE) as a binder, and a sheet-like polarizable electrode is previously fixed with a lead. The metal foil, plate, or mesh current collector is bonded with a conductive adhesive to form an electrode body, and a pair of the electrode bodies is wound through a separator to form a capacitor element. After that, put one in a bottomed metal case, and connect the lead leads connected to both electrode bodies to the inner end of the external terminal attached to the insulating sealing body. After fixing, the opening of the case is sealed with a sealing body.

However, a large current cannot be taken out instantaneously due to the small current capacity of the lead, so that the width of the current collector is made wider than that of the sheet-like polarizable electrode. There is proposed a dry battery type electric double layer capacitor in which a protruding part is provided and the protruding lead part is swaged so as to be in surface contact as a lead surface (Japanese Patent Laid-Open No. 4-15 / 1990).
2616 and Japanese Patent Application No. 9-96516).

[0004] For example, a protruding lead that protrudes the upper edge of the anode current collector and the lower edge of the cathode current collector from the sheet-like polarizable electrode and the separator, respectively. After the anode and cathode current collectors are arranged to face each other, a separator is interposed between them to form a capacitor element, and both protruding leads are respectively swept. The anode element is formed by forming the anode lead surface on the upper surface of the capacitor element and the cathode lead surface on the lower surface thereof. Such a capacitor element is placed in a metal case after being impregnated with an electrolytic solution.
A terminal plate is provided on the side of the anode lead surface and is in surface contact with the anode lead surface, and the protruding portion of the terminal plate protrudes outside through the sealing body. On the other hand, the cathode lead surface is in surface contact with the bottom of the metal case.

[0005]

In order to obtain a high withstand voltage using such a dry cell type electric double layer capacitor, it is necessary to arrange a plurality of dry cell type electric double layer capacitors in series. When arranged in series like this,
The anode lead surface of the first electric double layer capacitor element and the terminal plate, and the metal plate of the terminal plate and the second electric double layer capacitor.
Since the number of connection points is large, such as the metal case and the cathode lead surface of the capacitor element of the second electric double layer capacitor, the equivalent series resistance (ESR) increases. Also, since the electric double layer capacitors are housed in separate metal cases, the cost is high. Also, as the number of electric double layer capacitors increases, handling such as arrangement and fixing becomes troublesome.

According to the present invention, a high withstand voltage, a low equivalent series resistance,
It is an object of the present invention to provide a large-capacity electric double-layer capacitor that is inexpensive and easy to handle.

[0007]

According to the electric double layer capacitor of the present invention, a sheet-like polarizable electrode is arranged so as to be offset to an upper side edge portion of a wider metal current collector. An electrode body having a protruding lead portion formed below the current collector; and a polarizable electrode disposed offset to a lower side edge portion of the current collector so as to protrude above the current collector. The electrode body is formed and wound or laminated so that the respective polarizable electrodes face each other, and an electrolyte made of a solid electrolyte or gel is formed between the opposed electrode bodies, The upper and lower protruding leads are respectively swung inward by swaging or the like, and two or more capacitor elements each having a lead surface formed on the upper surface and the lower surface are provided. Are the same gold when they are in face contact and connected in series Ke - characterized in that it is housed in the scan.

In addition, a sheet-shaped polarizable electrode is disposed on one side of at least one surface of a wider tape-shaped metal current collector, and is positioned below the current collector. An electrode body having a protruding lead portion formed thereon, and an electrode having a polarizable electrode disposed offset to a lower side edge of the current collector and having a protruding lead portion formed above the current collector. The body is wound so that the respective polarizable electrodes face each other, and an electrolyte made of a solid electrolyte or a gel is formed between the facing electrode bodies.
A plurality of capacitor elements each having a lead portion which is laid down by swaging to form a lead surface on an upper surface and a lower surface are connected in series by contacting upper and lower lead surfaces with each other. Are housed in the same metal case in a state where they are connected to each other.

Further, a terminal plate is disposed on the upper surface of the uppermost capacitor element so as to make surface contact with the lead surface above the terminal plate, and the protruding portion of the terminal plate penetrates the insulating sealing member of the metal case. And the lead surface on the lower surface of the lowermost capacitor element is in surface contact with the bottom of the metal case.

Also, between the capacitor elements, between the terminal plate and the capacitor element, between the bottom of the metal case and the capacitor element connected thereto, or at least between the capacitor elements or the bottom of the metal case and connected thereto. A conductive spring member such as a metal disc spring is disposed between the capacitor element and the capacitor element.

[0011]

FIG. 1 is a sectional view showing an example of an electric double layer capacitor according to the present invention, and FIG. 2 is a view showing a part of the capacitor element in an unwound state. As shown in FIG. 2, the capacitor element 2 is formed by winding a cathode-side electrode body 3 and an anode-side electrode body 4 with separators 5 and 6 interposed therebetween.

The cathode-side electrode body 3 has a thickness of, for example, 20 to 100.
For example, a sheet-like polarizable electrode 3b having a thickness of 400 to 800 μm is attached to both sides of a tape-shaped current collector 3a made of a μm aluminum foil with a conductive adhesive. The polarizable electrode is, for example, activated carbon, carbon and polytetrafluoroethylene (PTFE) as a binder.
Is kneaded to form a sheet. Current collector 3a
May be a metal plate or mesh in addition to a foil.

The current collector 3a is wider than the polarizable electrode 3b, and the polarizable electrode 3b is arranged along the upper edge side of the current collector 3a, and thus is located on the lower edge side of the current collector 3a. Protrudes from the polarizable electrode 3b.
Are formed.

On the other hand, the anode-side electrode body 4 has, for example, a thickness of 20 to
For example, a sheet-like polarizable electrode 4b having a thickness of 400 to 800 μm is attached to both sides of a tape-shaped current collector 4a made of 100 μm aluminum foil with a conductive adhesive. Polarizing electrodes include, for example, activated carbon, carbon, and polytetrafluoroethylene (PT) as a binder.
FE) was kneaded to form a sheet. The current collector 4a may be a metal plate or mesh in addition to a foil.

The current collector 4a is wider than the polarizable electrode 4b, and the polarizable electrode 4b is arranged along the lower edge of the current collector 4a, so that it is located on the upper edge of the current collector 4a. Protrudes from the polarizable electrode 4b.
c is formed.

In FIG. 2, the polarizable electrodes 3b, 4b of the cathode-side electrode body 3 and the anode-side electrode body 4 are each a current collector 3b.
Although they are provided on both surfaces a and 4a, they may be provided only on one surface.

The separators 5 and 6 have a thickness of, for example, 50 to 20.
It is made of a sheet of 0 μm made of polypropylene or Manila hemp, and is wider than the polarizable electrodes 3b, 4b, but narrower than the current collectors 3a, 4a.

The cathode-side electrode body 3 and the anode-side electrode body 4 are arranged such that the polarizable electrode 3b and the polarizable electrode 4b face each other, and the separators 5 and 6 are arranged therebetween. At this time, the protruding lead portion 3c of the cathode-side electrode body 3 is located below the lower edge of the separators 5, 6, and the protruding lead portion 4c of the anode-side electrode body 4 is provided with the separator 5, 6
Is arranged to protrude above the upper edge. In this example, the separators 5 and 6 are interposed between the cathode-side electrode body 3 and the anode-side electrode body 4, but the separators 5 and 6 may be omitted.

Thereafter, the cathode side electrode body 3 and the anode side electrode body 4
And the outer periphery is stopped by a tape 2g to form a capacitor element 2. Thereafter, a solid electrolyte is formed between the electrode bodies 3 and 4 facing each other with the separators 5 and 6 interposed therebetween.
It is preferable that the carbon fibers 5 and 6 are carbonized before forming the solid electrolyte. As the solid electrolyte, for example, an organic semiconductor such as TCNQ (tetracyanoquinodimethane) or a conductive polymer solid electrolyte such as polypyrrol can be used. These are impregnated into a capacitor element in a liquid or monomer state, and then formed into a solid electrolyte by cooling or polymerization. Further, a gel electrolyte may be formed between the electrode bodies instead of the solid electrolyte.

Next, the protruding leads 3c, 4c are swaged so as to fall inward toward the center of the capacitor element 2, respectively. By this swaging, an anode lead surface 7 is formed on the upper surface of the capacitor element 2, and a cathode lead surface 8 is formed on the lower surface.

As shown in FIG. 1, in the electric double layer capacitor 1 of the present invention, six such capacitor elements 2 are housed in series in a vertically long metal case 10. Metal case 1
Numeral 0 is a bottomed cylindrical body made of aluminum, and the cathode lead surface 8 of the lowermost capacitor element 2f is a metal case 10
Is in surface contact with the bottom 11.

The anode lead surface 7 on the upper surface of the capacitor element 2f is in surface contact with the cathode lead surface 8 on the lower surface of the capacitor element 2e disposed thereon. In this way, the surface contact is made so as to be connected in series with the capacitor elements arranged one after another one after another.

The anode lead surface 7 on the upper surface of the uppermost capacitor element 2a is in surface contact with an aluminum terminal plate 12 disposed thereon. In each surface contact portion, a conductive adhesive may be used to ensure contact, or a conductive spring member such as a metal disc spring may be interposed. A lead rod 12a is provided at the center of the terminal plate 12 so as to protrude therethrough. The lead rod 12a penetrates an insulating sealing body 13 which seals an opening above the metal case 10. It protrudes to the outside. The sealing body 13 is made of, for example, rubber or phenol resin.

In the vicinity of the opening of the metal case 10, a lateral drawing groove 14 is formed in the metal case 10 in order to lock the sealing body 13.
After the sealing body 13 is placed on the lateral drawing groove 14, the opening edge 10a of the metal case 10 is curled inward to fix the sealing body 13. In order to enhance the sealing performance, the open edge 10 of the curled metal case is used.
“a” has entered the annular rubber portion 13 a provided with the sealing body 13. On the outside of the bottom of the metal case 10 except for a part of the center, a sleeve made of a heat-shrinkable synthetic resin is provided.
Is covered.

The number of capacitor elements 2 housed in the metal case 10 is not limited to six, but may be more or less.

[0026]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In a case with an aluminum bottom having a diameter of 89 mm and a length of 190 mm, a capacitor having a rating of 2.5 V and 800 F is housed in series with six capacitor elements (diameter of 80 mm and length of 30 mm). Was manufactured. The equivalent series resistance of this electric double layer capacitor was 98 mΩ. Rated 2.5 for comparison
The equivalent series resistance was 483 mΩ when six electric double layer capacitors each containing one V800F capacitor element were connected and arranged in series.

[0027]

According to the present invention, a solid electrolyte or an electrolyte comprising a gel is used in place of the electrolyte,
Since the electrolyte between the capacitor elements does not come into contact, an electric double layer capacitor having a high withstand voltage and a low equivalent series resistance can be obtained in one case. Also, since it is housed in one case, it is easy to handle and easy to use. Further, the cost can be reduced as compared with the case where each capacitor element is individually housed in a metal case.

A terminal plate is disposed on the upper surface of the uppermost capacitor element so as to make surface contact with a lead surface above the terminal plate, and the protruding portion of this terminal plate penetrates through an insulating sealing member made of a metal case. On the other hand, the lead surface on the lower surface of the lowermost capacitor element is in surface contact with the bottom of the metal case, so no lead leads or external terminals are required, and a large current is required. Can be taken out. Also, the work of welding the drawer leads and the external terminals to each other is not required, and the efficiency of the assembling work can be improved.

When a conductive spring member is disposed between the capacitor elements, between the terminal plate and the capacitor element, and between the bottom surface of the metal case and the capacitor element connected thereto, the Contact is reliably maintained.

[Brief description of the drawings]

FIG. 1 is a sectional view of an electric double layer capacitor according to the present invention.

FIG. 2 is a diagram showing a capacitor element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric double layer capacitor 2 (2a-2f) Capacitor element 2g Tape 3 Cathode side electrode body 3a Current collector 3b Polarizing electrode 3c Protruding lead part 4 Anode side electrode body 4a Current collector 4b Polarizing electrode 4c Protruding lead portion 5 Separator 6 Separator 7 Anode lead surface 8 Cathode lead surface 10 Metal case 10a Opening edge 11 Bottom 12 Terminal plate 12a Lead rod 13 Sealing body 13a Ring-shaped Rubber part 14 Horizontal drawing groove 15 Sleeve

Claims (7)

[Claims] 1. A sheet-shaped polarizable electrode is disposed offset to the upper side edge of a wider metal current collector, and a protruding lead portion is formed below the current collector. And the electrode body in which the polarizable electrode is disposed offset to the lower side edge of the current collector and the lead part protruding above the current collector is formed. Polar electrodes are arranged and wound or laminated so as to face each other, a solid electrolyte is formed between the opposing electrode bodies, and the above and below protruding leads are respectively depressed inward, and the upper surface and An electric double layer capacitor in which a plurality of capacitor elements each having a lead surface formed on the lower surface are housed in the same metal case in a state where the upper and lower lead surfaces are in surface contact and connected in series. 2. A sheet-like polarizable electrode, which is disposed on one side of an upper side edge of at least one side of a tape-shaped metal current collector having a larger width, and is disposed below the current collector. Overhanging release
An electrode body having a lead portion formed thereon and an electrode body having a polarizable electrode arranged offset to the lower side edge of the current collector and having a lead portion protruding above the current collector. The respective polarizable electrodes are arranged and wound so as to face each other, and a solid electrolyte is formed between the opposing electrode bodies,
The upper and lower protruding leads are respectively swung inward by swaging, and a plurality of capacitor elements each having a top surface and a bottom surface formed with a lead surface are formed. An electric double layer capacitor housed in the same metal case in a state of surface contact and serial connection. 3. A sheet-shaped polarizable electrode is disposed offset to the upper side edge of a wider metal current collector, and a protruding lead portion is formed below the current collector. And the electrode body in which the polarizable electrode is disposed offset to the lower side edge of the current collector and the lead part protruding above the current collector is formed. Polar electrodes are arranged and wound or laminated so as to face each other, and a solid electrolyte made of gel is formed between the opposing electrode bodies, and the above and below protruding leads are respectively depressed inward. A plurality of capacitor elements each having a lead surface formed on an upper surface and a lower surface, each of which is housed in the same metal case in a state where the upper and lower lead surfaces are in surface contact and connected in series. Multilayer capacitors. 4. A sheet-like polarizable electrode is disposed at one side of an upper side edge of at least one side of a wider tape-shaped metal current collector, and is disposed below said current collector. Overhanging release
An electrode body having a lead portion formed thereon and an electrode body having a polarizable electrode arranged offset to the lower side edge of the current collector and having a lead portion protruding above the current collector. Each of the polarizable electrodes is arranged so as to face each other and wound, and an electrolyte made of gel is formed between the opposing electrode bodies, and the upper and lower protruding leads are swaged, respectively. A plurality of capacitor elements which are folded inward and have lead surfaces formed on the upper and lower surfaces are placed in the same metal case in a state where the upper and lower lead surfaces are in surface contact and connected in series. The electric double layer capacitor housed. 5. A terminal plate, which is in surface contact with a lead surface above the uppermost capacitor element, is disposed on the upper surface of the uppermost capacitor element. A bottom surface of the lowermost capacitor element is in surface contact with the bottom of the metal case.
5. The electric double-layer capacitor according to any one of claims 4 to 4. 6. The electric double layer capacitor according to claim 1, wherein a conductive spring member is disposed at least on the capacitor element. 7. The electric double layer according to claim 1, wherein a conductive spring member is arranged at least between a bottom surface of the metal case and a capacitor element connected to the bottom surface. Capacitors.