JPH10275751A - Electric double layer capacitor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform further low equivalent series resistance to a winding length of an electrode, by winding a side edge of a current collector as a lead part, then tilting down the part to form a cathode lead surface and anode lead surface, and providing a terminal block in surface contact with one lead surface at a port sealing member. SOLUTION: A capacitor element 2 is spirally wound via separators 4, 5 between a cathode side electrode 2 and an anode side electrode 3. A sheet electrode 22 is moved to one side edge part 211 side of a current collector 21, and hence the other side edge of the collector 21 is formed in a protruding lead part 212. The parts 212, 311 protruding from the separator 4, 5 of the collectors 21, 32 are swaged to tilt down toward a center of a capacitor element 1. The element 1 is contained in a metal case, and then an opening of the case is sealed by a port sealing plate. A terminal block to an anode lead surface 30 of the element 2 is provided at an inner surface side in the case of the plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric double layer capacitor, and more particularly, to a large-capacity electric double layer capacitor having low ESR (equivalent series resistance) and good discharge characteristics, and a method of manufacturing the same. .

[0002]

2. Description of the Related Art An electric double layer capacitor is provided with a polarizable electrode formed into a sheet by kneading, for example, activated carbon, carbon, and polytetrafluoroethylene (PTFE) as a binder. The polarizable electrode is bonded to a current collector formed of a metal plate or a mesh to form an electrode body, and a pair of the electrode bodies is spirally wound via a separator.

According to this method, a large-capacity capacitor of, for example, about 1500 F can be obtained. However, when the electric charge is taken out, a lead wire is formed on the current collector by, for example, caulking as with a normal aluminum foil capacitor. I was trying to attach it.

However, a normal lead wire has a small allowable current value, so that a large current cannot be taken out.
Even if a plurality of lead wires are attached to the current collector at a predetermined interval, the current path through which electric charges are drawn out is limited to the lead wire portion. Not enough.

[0005]

Therefore, the present applicant has disclosed in Japanese Patent Application Laid-Open No. 4-152616 that the width of the current collector is made larger than the width of the sheet-like polarizable electrode, and the sheet-like polarizable electrode is collected by the collector. A pair of electrode bodies having a protruding lead portion on the other side edge side of the current collector by being attached to one side edge side of the current collector is used, and these electrode bodies are oriented in the opposite direction. It has been proposed that the lead portion of one of the electrode bodies is brought into surface contact with the bottom of the metal case after being wound through a separator so as to face the metal case.

According to this, since the lead portion of one electrode body comes into surface contact with the metal case, the ESR in this portion is reduced, but the lead portion of the other electrode body is formed of the above-mentioned prior art. The ESR is still high because the lead wire is connected like
2. Description of the Related Art As electric double-layer capacitors have increased in capacity, further reduction in ESR is desired.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide an electric double layer capacitor and a method of manufacturing the same, which can further reduce the ESR with respect to the winding length of the electrode body. To provide.

[0008]

In order to achieve the above object, the present invention provides an electrode assembly comprising a sheet-shaped polarizable electrode attached to at least one surface of a tape-shaped current collector made of a metal plate or mesh. In an electric double-layer capacitor in which a capacitor element formed by winding a pair of the electrode bodies with a separator interposed therebetween is housed in a cylindrical metal case having a bottom and the opening of the metal case is sealed with a sealing member, Each of the electrode bodies has a current collector whose width is larger than the width of the polarizable electrode, and one of the polarizable electrodes and the other polarizable electrode are opposite side edges of each of the current collectors. Along the opposite side edge of each current collector so as to become a protruding lead portion, and the separator has an intermediate width between the current collector and the polarizable electrode, The lead of each electrode body is In a state of being incorporated defeated by swaging toward the center of the capacitor element, with lead portions of the one of which surface contact with the bottom of the metal case,
The sealing member is provided with a terminal plate that comes into surface contact with the other lead portion.

In this case, it is preferable that the one lead portion is in surface contact with the bottom of the metal case via a conductive adhesive, whereby the electrical and mechanical stability is improved. Characteristics are guaranteed.

The terminal plate includes a contact substrate having a size capable of making surface contact with the other lead portion, and a lead rod drawn out of the contact substrate through the sealing member. However, if the lead bar is arranged on the axis of the metal case, the electric double layer capacitor can be of a dry battery type, for example.

Further, according to the manufacturing method of the present invention, a band-shaped sheet electrode having a predetermined width is attached along one side edge of a metal tape-shaped current collector having a width larger than the width. A pair of electrode bodies having the other side edge of the current body as a protruding lead portion are opposed to each other so that their respective lead portions face in opposite directions, and the current collector and the electrode material are located between the electrode bodies. The capacitor element is wound by winding with a separator having an intermediate width between the polarizable electrodes, and the capacitor element is impregnated with an electrolytic solution, and the lead portions of the electrode bodies protruding from the separator are swaged. After falling down toward the center of the above capacitor element,
The lead portion of the one electrode body is brought into surface contact with the bottom of the metal case while being housed in a bottomed cylindrical metal case, and the opening of the metal case is in contact with the lead of the other electrode body. It is characterized in that it is sealed with a sealing member provided with a contacting terminal plate.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, for better understanding of the technical concept of the present invention, an embodiment will be described with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of an electric double layer capacitor according to the present invention, and FIG. 2 is a perspective view showing a state where a part of the capacitor element is unwound.

According to this, the electric double layer capacitor C includes the capacitor element 1 in which a pair of electrode bodies is spirally wound via a separator. That is, in this embodiment, the capacitor element 1 is configured by spirally winding the cathode-side electrode body 2 and the anode-side electrode body 3 with the separators 4 and 5 interposed therebetween.

The cathode-side electrode body 2 has a thickness of, for example, 20 to 100.
For example, a sheet-shaped polarizable electrode 22 having a thickness of 400 to 800 μm is formed on a tape-shaped current collector 21 made of an aluminum foil having a thickness of
It is made up of the following. This polarizable electrode is made of a sheet formed by kneading, for example, activated carbon, carbon and PTFE as a binder, as in the prior art. Hereinafter, in this embodiment, the polarizable electrode is simply referred to as a sheet electrode.

The current collector 21 may be either a plate or a mesh, but has a width larger than the width of the sheet electrode 22, and the sheet electrode 22 is formed on one side edge of the current collector 21. It is arranged along (upper side edge in FIG. 2) 211. In other words, the sheet electrode 22 is shifted toward the one side edge 211 of the current collector 21, so that the other side edge (the lower side edge in FIG. 2) of the current collector 21 is protruded. The lead portion 212 is provided.

The anode-side electrode body 3 has a thickness of, for example, 20 to 100.
For example, a sheet electrode 32 having a thickness of 400 to 800 μm is bonded to a tape-shaped current collector 31 made of an aluminum foil having a thickness of μm.
1 is larger in width than the width of the sheet electrode 32, and the sheet electrode 32 is arranged along the other side edge (the lower side edge in FIG. 2) 312 of the current collector 31. That is, the sheet electrode 32 is connected to the other side edge 312 of the current collector 31.
Thus, one side edge (the upper side edge in FIG. 2) of the current collector 31 is formed as a protruding lead 311.

In FIG. 2, the sheet electrode 22 of the cathode side electrode body 2 is on the back side of the current collector 21, whereas the sheet electrode 32 of the anode side electrode body 3 is on the front side of the current collector 31. The sheet electrodes 22 and 32 may be provided on both surfaces of the current collectors 21 and 31, respectively, although they are provided so as to face each other. The current collectors 21 and 31 have the same width, and the sheet electrodes 22 and 32 have the same width.

The separators 4 and 5 have a thickness of, for example, 50 to 20.
It is made of a sheet made of polypropylene or Manila hemp having a thickness of 0 μm, and has a width smaller than the width of the current collectors 21 and 31, but larger than the sheet electrodes 22 and 32, that is, an intermediate width between the two.

When the cathode-side electrode body 2 and the anode-side electrode body 3 are wound, one of the separators 4 is a sheet electrode 22.
And 32 are disposed so as to isolate them, and the other separator 5 is disposed between the current collectors 21 and 31, with the separators 4 and 5 being connected to the current collector 21 and the current collector 21. Each protruding lead portion 212, 31 of the body 31
The relative position with respect to the current collectors 21 and 31 is determined so that 1 protrudes further outward from the side edges of the separators 4 and 5.

After positioning the respective members, the cathode-side electrode body 2 and the anode-side electrode body 3 are wound and taped to form the capacitor element 1, and then immersed in an electrolytic solution.
Preferably, the capacitor element 1 is impregnated with an electrolytic solution by vacuum impregnation.

Next, the separators 4, 4 of the current collectors 21, 31
The lead portions 212 and 311 protruding from the position 5 are swaged so as to fall down toward the center of the capacitor element 1. By this swaging, an anode lead surface 30 is formed on one end surface (the upper end surface in FIG. 2) of the capacitor element 1 by the lead portion 311 which is depressed.
On the other end surface of the capacitor element 1 (the lower end surface in FIG. 2), a cathode lead surface 20 is formed by the lead portion 212 which has been depressed.

Thereafter, the capacitor element 1 is stored in the metal case 6. In this embodiment, the metal case 6 is formed of a cylindrical body having a bottom of aluminum, and the cathode lead surface 20 of the capacitor element 1 is in planar contact with the bottom 61 thereof. In this case, in order to improve the electrical connection and securely fix the capacitor element 1 to the metal case 6, it is preferable to attach the cathode lead surface 20 to the bottom 61 of the metal case 6 with a conductive adhesive. .

Subsequently, the opening of the metal case 6 is
Seal with. According to this embodiment, for example, a rubber-clad laminate or a phenolic resin sealing plate is used for the sealing plate 7, and the inner surface of the sealing plate 7 facing the inside of the case is provided with respect to the anode lead surface 30 of the capacitor element 1. A terminal plate 8 is provided.

That is, the terminal plate 8 is connected to the anode lead surface 3.
A contact substrate 81 having a size capable of making a surface contact with the contact substrate 81 and a lead rod 82 extending from the contact substrate 81 to the outside through the sealing plate 7 are provided. The lead rod 82 is arranged on the axis of the metal case 6. The terminal plate 8 is preferably made of aluminum, like the metal case 6.

On the opening side of the metal case 6, a horizontal throttle groove 62 for locking the sealing plate 7 at the sealing position is formed. After the sealing plate 7 is placed on the horizontal throttle groove 62, The opening edge 63 of the metal case 6 is curled inward.
Thus, the opening of the metal case 6 is sealed by the sealing plate 7 with the terminal plate 8 and the anode lead surface 30 in surface contact.

In this embodiment, in order to enhance the sealing performance, an annular rubber 71 is provided on the upper surface (outer surface) of the sealing plate 7 so as to cut into the opening edge 63 of the metal case 6 during curling. I have. In this embodiment, a sleeve 9 made of a heat-shrinkable synthetic resin tube is put on the metal case 6.

In this way, for example, a large-capacity electric double layer capacitor having a similar shape to a single type dry battery can be obtained. However, unlike the above-described embodiment, each of the lead portions 212 and 311 of the current collectors 21 and 31 is obtained. May be impregnated with an electrolytic solution after swaging to form the cathode lead surface 20 and the anode lead surface 30, or after housing the capacitor element 1 in the metal case 6.

The polarizable electrodes 22 and 32 may be coated electrodes or activated carbon fiber electrodes. Further, when the capacitor element 1 is housed in the metal case 6, the anode lead surface 30 may be opposed to the case bottom 61, contrary to the above embodiment. In short, it should be understood that the present invention is not limited to the above-described embodiment, but includes various modifications without departing from the technical idea thereof.

[0029]

As described above, according to the present invention,
The side edges of the current collectors of the cathode and anode are formed as protruding leads, and after being wound as a capacitor element, each lead is fallen down by swaging, and the cathode lead surfaces are formed on both end faces of the capacitor element. The formation of the anode lead surface and the provision of a terminal plate in surface contact with one of the lead surfaces on the sealing member provide an extremely good electric double layer capacitor with low internal resistance and large current discharge characteristics. .

[Brief description of the drawings]

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

FIG. 2 is an exemplary perspective view showing a state where a part of the capacitor element of the embodiment is unwound;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Capacitor element 2 Cathode side electrode body 20 Cathode lead surface 21 Current collector 22 Sheet-shaped polarizable electrode 212 Protruding lead part 3 Anode side electrode body 30 Anode lead surface 31 Current collector 311 Protruding lead part 32 Sheet-shaped polarizability Electrodes 4, 5 Separator 6 Metal case 61 Bottom 7 Sealing plate 8 Terminal plate 81 Contact board 82 Lead rod

Claims (6)

[Claims] 1. An electrode body comprising a sheet-like polarizable electrode attached to at least one surface of a tape-shaped current collector made of a metal plate or mesh, and a pair of the electrode bodies wound around a separator. In an electric double-layer capacitor in which a capacitor element is housed in a cylindrical metal case having a bottom and the opening of the metal case is sealed with a sealing member, the width of the current collector of each of the electrode bodies is a polarizable electrode. And the other polarizable electrode and the other polarizable electrode are relatively small so that the opposite side edge of each current collector forms a protruding lead. The separator is arranged along the opposite side edge of the current collector, the separator has an intermediate width between the current collector and the polarizable electrode, and the lead portion of each electrode is directed toward the center of the capacitor element. Defeat by swaging In the inserted state, one of the leads is in surface contact with the bottom of the metal case,
An electric double layer capacitor, wherein the sealing member is provided with a terminal plate which is in surface contact with the other lead portion. 2. The electric double layer capacitor according to claim 1, wherein the one lead portion is in surface contact with the bottom of the metal case via a conductive adhesive. 3. The terminal board includes a contact board having a size capable of making a surface contact with the other lead portion, and a lead rod extending from the contact board to the outside through the sealing member. The electric double layer capacitor according to claim 1, wherein: 4. The electric double layer capacitor according to claim 3, wherein the lead bar is disposed on an axis of the metal case. 5. A strip-shaped sheet electrode having a predetermined width is attached along one side edge of a metal tape-shaped current collector having a width larger than the width, and the other side edge of the current collector is attached. A pair of electrode bodies each having a protruding lead portion are opposed to each other so that the respective lead portions face in opposite directions, and an intermediate width between the current collector and the polarizable electrode is provided between the electrode bodies. It was wound with a separator interposed between it and a capacitor element, and the capacitor element was impregnated with electrolyte,
After the lead portions of the respective electrode bodies protruding from the separator are respectively swaged down toward the center of the capacitor element, the lead parts of the one electrode body are housed in a bottomed cylindrical metal case. The opening of the metal case is sealed with a sealing member provided with a terminal plate which is in surface contact with the lead of the other electrode body. Manufacturing method of multilayer capacitor. 6. The terminal plate according to claim 5, wherein a lead rod is provided on the axis of the metal case and extends through the sealing member and is drawn out to the outside.
3. The method for manufacturing an electric double-layer capacitor according to claim 1.