JPH01313918A - Laminated electric double layer capacitor - Google Patents

Abstract

PURPOSE:To form the title capacitor at lower cost in a thinner shape by composing a second electrode plate of a nonmetallic material while conducting sealing with a resin. CONSTITUTION:At least sections facing each capacitor element of a second electrode plate 6 arranged between the capacitor elements consist of an ion impermeable nonmetallic material while flanges made up of an electrical insulating resin are connected continuously to the peripheries of the sections, and said flanges and each periphery 1a, 12a of first and third electrode plates 1, 12 are sealed with the electrical insulating resin. A conductive synthetic resin board, a conductive rubber sheet or a carbon board or the like are cited as the nonmetallic material. Accordingly, manufacturing cost can further be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multilayer electric double layer capacitor, and more specifically, to a one-cell two-layer electric double layer capacitor.

[Conventional technology]

Electric double layer capacitors are based on the principle of storing charge in the electric double layer formed at the interface between a polarizable electrode with a large surface area such as activated carbon and an electrolyte, and are far more effective than other capacitors. It is attracting attention because it can provide large capacitance.

This electric double layer capacitor is usually called a coin-shaped unit cell or a button-shaped unit cell, and is constructed as follows. That is, it includes a case main body in the shape of a dish with a shallow bottom and a cap that is placed over the case main body, and polarizable electrodes are attached to each bottom of the case main body through a conductive adhesive.

After each electrode is impregnated with a predetermined electrolyte, a separator is placed between them. Then, a gasket is inserted into the case body, and the opening edge of the case body is caulked, thereby sealing the periphery of the cap.

A unit cell is obtained in this way, but as a backup power supply for RAM-IC memory, which is its main use, a working voltage of 5.5V is required, but the withstand voltage of this unit cell is is approximately 0.8 V when using an aqueous electrolyte, and approximately 1.8 V to 2.8 V when using a non-aqueous electrolyte, so two unit cells are usually connected in series. It is necessary to use 7 pieces stacked together.

Therefore, conventionally, inside a cylindrical metal exterior case with a bottom,
A cell laminate is housed in which a plurality of the above unit cells are integrally laminated with, for example, an electrically insulating and heat-shrinkable sleeve, and an electrically insulating plate is interposed between the electrode plates, both of which have lead-out leads, on top of the cell laminate. Place the electrode unit made of
The opening edge of the exterior case is caulked to seal the exterior case (for example, Utility Model Publication No. 62-1639
According to this, one electrode surface of the cell stack is drawn out from the lower electrode plate of the electrode unit placed so as to be in contact with it, and the other electrode surface of the cell stack is drawn out from the lower electrode plate of the electrode unit placed in contact with it. The electrode surface is drawn out to the outside through the outer case that contacts it at the bottom and the upper electrode plate of the electrode unit that contacts the caulked opening edge of the outer case.

[Problem to be solved by the invention]

However, in the above-mentioned multilayer electric double layer capacitor, a cell stack consisting of a plurality of unit cells stacked in series is housed in an exterior case, and an electrode unit is placed inside the opening of the case. Since the outer case must be integrated by caulking, there is a problem in that the number of manufacturing steps is large and the work is complicated.

Therefore, the present applicants have proposed a laminated electric double layer capacitor that solves the above-mentioned problems and reduces manufacturing costs by simplifying the manufacturing process, for example, in Japanese Patent Application No. 18581/1983. The outline of the structure is as follows.

A multilayer type electric double layer capacitor that utilizes an electric double layer formed at the interface between a pair of polarizable electrodes and a non-aqueous electrolyte that face each other with a separator in between. Two capacitor elements are stacked in series. In an electric double layer capacitor, a first electrode plate whose inner surface abuts the anode side of one capacitor element and also serves as an exterior case; a third electrode plate whose inner surface abuts the cathode side of the other capacitor element and which also serves as an exterior case; a second electrode plate disposed between the first electrode plate and the third electrode plate so that both surfaces abut the cathode side of the one capacitor element and the anode side of the other capacitor element, respectively; The circumferential ends of the first, second and third electrode plates are integrally joined via an electrically insulating material.

According to this, for example, two capacitor elements are housed in a series-connected state in one exterior case, so it has the same function as a multilayer electric double layer capacitor that houses two unit cells. A self-supporting capacitor is obtained.

By the way, in this prior invention, the first and second
and the third electrode plate, for example, 5US316L,
Corrosion-resistant and expensive metals such as S U 5447J 1 are used. Since the first and third electrode plates also serve as exterior cases, such metal materials are required for their mechanical strength, but this is not necessary for the second electrode plate, reducing costs. There is still room for. Further, since the peripheral edges of the first and second electrode plates, which also serve as an exterior case, are caulked and sealed, there is a limit to how thin the structure can be made.

Therefore, an object of the present invention is to provide a multilayer electric double layer capacitor that can be formed at lower cost and thinner.

[Means to solve the problem]

In order to achieve the above object, in the present invention, at least the portion of the second electrode plate disposed between the capacitor elements facing each capacitor element is made of an electrically conductive and ion-impermeable nonmetallic material.

A flange made of electrically insulating resin is installed around its periphery.

The peripheral edges of the flange and the first and third electrode plates are sealed with electrically insulating resin.

Examples of this non-metallic material include conductive synthetic resin plates, conductive rubber sheets, carbon plates, etc.
Preferably, a rubbery polymer and a conductive substance such as carbon are added to a synthetic resin such as polypropylene.

[For production]

According to the above configuration, since the second electrode plate is made of a non-metallic material, it can be made inexpensive. Further, since the first and third electrode plates are sealed with resin, the mechanical strength that can withstand caulking is not required, which allows the case wall thickness to be made thinner.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

As shown in FIG. 1, this electric double layer capacitor includes a first electrode plate 1 made of stainless steel, for example, which also serves as an exterior case. The first electrode plate 1 has a peripheral end portion 1a having an L-shaped cross section, and a polarizable electrode 2 is fixed to the inner surface of the first electrode plate 1 via a conductive adhesive layer 3. Further, this capacitor has a peripheral end portion 12a having an L-shaped cross section similarly to the first electrode plate 1, and has a third electrode plate 12 made of stainless steel, for example, which also serves as an exterior case. A polarizable electrode 11 is fixed to the inner surface of the third electrode plate 12 via a conductive adhesive layer 13. A second electrode plate 6 is arranged between the first electrode plate 1 and the third electrode plate 12, and polarizable electrodes 5 and 8 are disposed on both sides of the second electrode plate 6, respectively. The 0-polarizable electrodes 2 and 5 and the polarizable electrodes 8 and 11, which are fixed to each other via the capacitor 9, are arranged facing each other with the separators 4 and 10 made of, for example, polypropylene or glass fiber non-woven fabric, respectively. A and a second capacitor element B are configured. In this embodiment, the polarizable electrodes 2, 5, 8, and 11 are each made of, for example, a mixture of activated carbon powder, carbon, and polytetrafluoroethylene, formed into a sheet, stretched, and punched into a disk shape.

Referring to FIGS. 2 and 3, at least the portion of the second electrode plate 6 facing each capacitor element A, B is made of a conductive and ion-impermeable nonmetallic material 6a, and the periphery thereof A flange 6b made of an electrically insulating resin such as polypropylene is connected to the flange 6b. Examples of the non-metallic material 6a include a conductive synthetic resin, a conductive rubber sheet, a carbon plate, etc., but preferably a synthetic resin material such as polypropylene to which a conductive substance such as carbon is added together with a rubbery polymer is preferable.

Further, according to the present invention, the flange 6a of the second electrode plate 6 and each peripheral end portion 1a, 12 of the first and second electrode plates 1, 12
A is sealed with an electrically insulating resin 14 such as ionomer resin or epoxy resin.

This laminated electric double layer capacitor having one or more configurations, whose functions and effects will be explained next, has a second electrode plate 6 in which capacitor element A and capacitor element B are made of a non-metallic material, as shown in the figure. A dish-shaped first electrode plate 1 and a third electrode plate 12 are stacked in series through the electrode plate 6 and function as an exterior case with the flange 6b of the same electrode plate 6.
Since each peripheral end 'a*12a of is sealed with resin, manufacturing costs can be further reduced, and the case wall thickness can be reduced to, for example, 0.05 m+.

〔Effect of the invention〕

As explained above, according to the present invention, the second electrode plate is made of a non-metallic material and is sealed with resin.
A thinner multilayer electric double layer capacitor can be obtained at low cost.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of a multilayer electric double layer capacitor according to the present invention, Fig. 2 is a sectional view of a second electrode plate used in the embodiment, and Fig. 3 is a sectional view of the second electrode plate used in the same embodiment. FIG. In the figure, 1 is the first electrode plate, la, 12a is the peripheral edge, 2.5
, 8, 11 are polarizable electrodes, 3, 7, 9.13 are conductive adhesives, 4.10 are separators, 6 is a second electrode plate, 6a is a non-metallic material, 6b is a flange, 12 is a third electrode Board, 14
is the sealing resin. Patent applicant Elna Co., Ltd.

Claims (2)

[Claims] (1) A first capacitor element having a separator interposed between a pair of polarizable electrodes; a second capacitor element;
a first electrode plate that also serves as an exterior case, the inner surface of which is electrically connected to the anode side of the first capacitor element; and a third electrode plate that also serves as an exterior case, the inner surface of which is electrically joined to the cathode side of the second capacitor element. the first electrode plate and the third electrode plate such that both surfaces thereof are electrically connected to the cathode side of the first capacitor element and the anode side of the second capacitor element, respectively;
and a second electrode plate disposed between the electrode plate and the second electrode plate, wherein at least a portion facing each of the capacitor elements is made of an electrically conductive and ion-impermeable nonmetallic material. , a laminated type characterized in that a flange made of an electrically insulating resin is continuously provided on the periphery of the flange, and each of the flange and the periphery of the first and third electrode plates is sealed with an electrically insulating resin. Electric double layer capacitor. (2) The laminated electric double layer capacitor according to claim 1, wherein the non-metallic material is a synthetic resin material such as polypropylene to which a conductive substance such as carbon is added together with a predetermined amount of rubbery polymer.