JPS63184315A - Electric double-layer capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an electric double layer capacitor.

[Conventional technology]

Electric double layer capacitors are generally manufactured by stacking a plurality of electric double layer capacitor units (hereinafter referred to as units) and enclosing the units in an exterior body in a state where the units are compressed in the thickness direction.

The exterior body consists of a metal case, a metal lid, and a resin backing.
For example, the electric double layer capacitor using the metal case (for example, Japanese Utility Model Application Publication No. 61-59332) has excellent performance, but the metal case, lid, etc.
Since an insulating plate is required in addition to a backing, the cost of materials required for the exterior is high, the structure is complex and it takes a lot of man-hours to encapsulate the unit, and it is difficult to tighten the opening end of the metal case inward. Since strict precision is required, there was a problem of poor productivity.

Therefore, the inventors of the present invention have conducted various studies in order to lower costs and improve productivity by using a resin exterior. We have developed an electric double layer capacitor in which units are stacked and housed in a compressed state, and have already filed an application for the same (Utility Application No. 109616/1983).

By the way, in order to store the units in a stacked and compressed state inside the exterior body consisting of the resin case and the resin lid as described above, the case 2 is explained with reference to FIGS. 6 and 7.
A plurality of units 1 are stacked and stored in the case 2.
The lid 3 is fitted into the opening of the lid 3, and the lid 3 is pressed from the top to compress the unit 1 in its thickness direction and to compress the unit 1.
While increasing the contact between the current collectors 4a and 5a of the electrode terminals 4.5, apply adhesive 7 to the joint between the case 2 and the lid 3 to bond the case 2 and the lid 3, and then complete the unit. It is necessary to suppress the repulsive force that causes the unit 1 to return to its original thickness so that the compressed state in the thickness direction of the unit 1 is maintained. This is because if the compressed state of the unit or the close contact between the unit and the current collecting portion of the electrode terminal are impaired, the internal resistance increases and the device becomes impractical.

However, when bonding the case and the lid with adhesive as described above, if the lid is not pressed against the unit until the adhesive hardens, the compressed state of the unit and the current collector between the unit and electrode terminal may deteriorate. As shown in FIG. 7, the lid 3 must be kept pressed downward with the pressing member 20, but the adhesive 7 applied to the joint between the lid 3 and the case 2 may Problems arise in that the particles flow from the outer circumferential portion 3b of the lid 3 toward the inner circumferential side and stain the pressing member 20, or that the pressing member 20 and the lid 3 are bonded together. In particular, in order to improve the sealing performance of the joint between the inner circumferential surface of the case 2 and the outer circumferential surface of the lid 3, a low-viscosity adhesive is preferably used. Do not allow the uncured adhesive 7 to flow to the inner circumference of the lid 3 and stain the pressing member.
The pressing member and the lid may be bonded together.

[Problem that the invention seeks to solve]

This invention solves the problems that the above-mentioned conventional products had, such as the adhesive for bonding the case and the lid staining the pressing member and the fact that the pressing member and the lid are glued together. An object of the present invention is to provide an electric double layer capacitor that does not cause troubles due to adhesive flowing out during bonding.

[Means for solving problems]

The present invention prevents uncured adhesive from flowing to the center of the lid and staining the pressing member or causing the pressing member and the lid to adhere to each other by applying the adhesive at a position lower than the center of the lid. This prevents this from happening.

That is, in the present invention, the lid is formed so that the upper surface of the outer periphery of the lid is lower than the inner periphery, that is, the upper surface of the central portion of the lid, and the adhesive is applied to the lower end surface of the outer periphery of the lid and the case. By applying the adhesive to the joint with the inner peripheral surface of the lid, the adhesive application position is lower than the center of the lid, and the applied adhesive stays in the recess formed on the outer periphery of the lid and flows to the center of the lid. This prevents uncured adhesive from flowing into the center of the lid and staining the pressing member, or from adhering the pressing member to the lid, thereby preventing problems caused by adhesive application. This prevents the occurrence.

In the present invention, the case and lid are made of an insulating material to prevent short circuits inside the electric double layer capacitor. Examples of the case and lid made of the insulating material include polycarbonate, polybutylene terephthalate, A case made of resin such as polyethylene terephthalate, or a case or lid made of a suitable base material and coated with resin is used.

The adhesive to be applied to the joint between the case and the lid may be, for example, a cyanoacrylate instant adhesive or an ultraviolet curing resin (for example, an acrylic ester ultraviolet curing resin, an unsaturated polyester/styrene ultraviolet curing resin). , epoxy/Lewis acid-based ultraviolet curing resin, polyene/
It is recommended to use an adhesive that hardens in a short time, such as thiol-based purple A-external radiation curing resin, etc., for temporary fixing, and then use an epoxy resin adhesive, urethane resin adhesive, etc. for permanent fixing. preferable.

In addition, since the above adhesive also serves to improve the airtightness of the joint between the case and the lid, it can flow into the minute gap between the outer peripheral surface of the lid and the inner peripheral surface of the case and fill the gap. Since it is preferable to use an adhesive with a reasonably low viscosity, in some cases the adhesive may flow into the case through the gap between the outer circumferential surface of the lid and the inner circumferential surface of the case, and the It may enter between the current collecting part of the terminal and the unit and insulate the electrode terminal and the unit.

Therefore, even if the adhesive flows into the case and enters between the current collecting part of the electrode terminal and the unit, a conductive adhesive is used as the adhesive so that conductive defects due to the adhesive will not occur. It is also preferably employed.

Examples of such conductive adhesives include silver-epoxy resin adhesives, carbon-epoxy resin adhesives,
Examples include copper-epoxy resin adhesive, nickel-epoxy resin adhesive, silver-polyester adhesive, silver-acrylic resin adhesive, and the like.

The means for applying the adhesive is not particularly limited, and
Various application methods are used, but since the electric double layer capacitor itself is small, adhesive is poured from the needle-like tip of a syringe into the minute gap at the joint between the outer circumferential surface of the lid and the inner circumferential surface of the case. It is preferable to apply the adhesive so that it rises slightly.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

1 to 3 are sectional views showing embodiments of the electric double layer capacitor of the present invention, and FIG. 4 is an enlarged sectional view showing a unit used in the electric double layer capacitor. FIG. 5 is a sectional view showing the electric double layer capacitor of the present invention shown in FIG. 1 during assembly. In addition, in FIG. 1, FIG. 2, FIG. 3, FIG. 5 showing the electric double layer capacitor, and FIG. 6 and FIG. 7 showing the conventional example described above, the unit is shows only the outside schematically.

First, to explain the unit, for example, as shown in FIG. 4, the unit l consists of two opposing current collector plates 1a,
a pair of electrodes 1d separated by a separator 1c between lb;
1e, and insulating rings If, I are arranged outside the peripheral edge thereof.
g.

The current collector plates 1a and 1b in the unit 1 are made by kneading conductive carbon black into an organic material such as polypropylene with a small amount of rubber added to give it elasticity, and the insulating rings 1f and 1g are made of, for example, It is made of acid-resistant rubber such as butyl rubber or ethylene propylene diene rubber, and between the insulation rings 1f and 1g, between the insulation ring 1f and the current collector plate 1a, and between the insulation ring 1g and the current collector plate 1b. It is bonded using an appropriate bonding means such as adhesive or ultrasonic welding.

For example, the electrodes 1d and 1e are made by applying a slurry of powdered unactivated carbon to activated carbon fiber cloth, and after drying, applying a slurry of, for example, 33
% sulfuric acid aqueous solution.

The electrodes 1d and le become positive and negative electrodes, respectively, by voltage application after forming the capacitor. This electrode 1d,
, le is made of, for example, a microporous polypropylene film.

This unit 1 has a thickness of 1 mm and a diameter of 10.0 mm.
mm, and when assembling an electric double layer capacitor, it increases the closeness inside the electrodes, the closeness between the electrodes and the current collector plate, and further increases the closeness between stacked units 1. to reduce internal resistance, approximately 2 mm in the thickness direction.
It is compressed by about 0%.

Next, the electric double layer capacitor according to the first embodiment shown in FIG. unit 1 on the outer peripheral surface and both ends of
The outer peripheral edge of the unit is covered with a heat-shrinkable resin tube 6 such as a heat-shrinkable polyester resin tube.The stacked body of the unit is placed in the heat-shrinkable resin tube 6, and the heat-shrinkable resin tube 6 is shrunk by heating. After the lid 3 is fitted into the opening of the case 2, as shown in FIG.
The central part 3c of the lid 3 is pressed downward by the pressing member 20 to adjust the compression ratio of the unit 1 to a desired value, and the current collector 4a of the unit 1, the electrode terminal 4, and the electrode terminal 5 are Adhesive 7 is applied to the joint between the inner peripheral surface of the case 2 and the outer peripheral surface of the lid 3 while bringing the electrical part 5a into close contact, and the applied adhesive 7 is formed on the outer peripheral part 3b of the lid 3. Recess 3
The uncured adhesive 7 remains at the center part 3C of the lid 3.
The case 2 and the lid 3 are manufactured by adhering the case 2 and the lid 3 while preventing the liquid from flowing and staining the pressing member 20 or adhering the pressing member 20 and the lid 3.

The case 2 is made of polybutylene terephthalate, and the plate-shaped current collecting part 4a of one electrode terminal 4 is arranged on the inner surface of the bottom part 2a.
b passes through a hole provided in the center of the bottom 2a of the case 2, and its tip protrudes outside the case 2. In this embodiment, the electrode terminal 4 is made of nickel, and the electrode terminal 4 and the case 2 are fitted together after the case 2 is made, so that the electrode terminal 4 is inserted into the hole provided in the bottom 2a of the case 2. An adhesive 8 is filled in the gap between the electrode terminal 4 and the lead portion 4b. However, when molding the case 2, the case 2 and the electrode terminal 4 can be integrally molded by so-called insert molding, and in that case, the electrode terminal 4 and the case 2 as described above can be molded together. The adhesive 8 for filling the gap between the lead portion 4b of No. 4 and the case 2 is not required.

The lid 3 is made of polybutylene terephthalate,
A plate-shaped current collecting part 5a of an electrode terminal 5 made of nickel is arranged on the lower surface 3a of this lid 3.
b passes through a hole provided in the center of the lid 3, and its tip protrudes upward. In this embodiment, since the electrode terminal 5 is fitted after the lid 3 is manufactured, the gap between the hole in the lid 3 and the lead portion 5b of the electrode terminal 5 inserted into the wire hole is filled. is filled with adhesive 9. However, similarly to the case 2, the M3 and the electrode terminal 5 can also be molded in a state in which the electrode terminal 5 and the lid 3 are integrated using the so-called insert molding method when molding the lid 3. When the electrode terminal 5 is insert-molded into the lid 3, the adhesive 9 is not necessary. Note that the drawing shows that the adhesive 9 filled in the gap between the hole in the lid 3 and the lead part 5b of the electrode terminal 5 inserted into the wire hole reaches the pressing member 20 before hardening. It may flow and stain the pressing member 20, or the pressing member 2
There may be a concern that the adhesive 9 and the lid 3 may be glued together, but the application of the adhesive 9 to fill the gap between the lid 3 and the lead portion 5b of the electrode terminal 5 should be done before assembling the electric double layer capacitor. If you do this, the adhesive 9 will be hardened and will not flow when assembling the electric double layer capacitor, so the unhardened adhesive 9 will be applied to the pressing member 20.
There is no possibility that the liquid will flow to the surface and stain the pressing member or cause the pressing member 20 and the lid 3 to adhere to each other.

The outer peripheral part 3b of the lid 3 is made slightly thinner than the central part 3c of the lid 3, and the upper surface of the outer peripheral part 3b of the lid 3 is formed to be lower than the upper surface of the central part 3c of the lid 3. A recess 3d is formed on the outer periphery 3b of the lid 3, and the adhesive 7 applied to the joint between the outer periphery of the lid 3 and the inner periphery of the case 2 is formed on the outer periphery 3b of the lid 3. This prevents the uncured adhesive 7 from flowing into the center portion 3c of the lid 3 and staining the pressing member 20, or causing the pressing member 20 and the lid 3 to adhere to each other. is prevented. In the present invention, the central portion 3c of the lid 3 refers to the inner circumferential portion of the outer circumferential portion 3b, and does not mean only the central portion of M3.

In this embodiment, a carbon-epoxy resin conductive adhesive is used as the adhesive 7 for bonding the case 2 and the lid 3 together, and the adhesive 8.9 is also the adhesive 7. Similarly to 7, a carbon-epoxy resin based conductive adhesive is used.

Therefore, as mentioned above, the plate-shaped current collecting part 5a of the electrode terminal 5 is arranged on the lower surface 3a of the lid 3, but even if the adhesive 7 applied to the joint between the lid 3 and the case 2 is 3 flows into the case 2 through a minute gap at the joint between the outer circumferential surface of the unit 1 and the inner circumferential surface of the case 2, and further flows into the current collecting portion 5 of the unit 1 and the electrode terminal 5.
Even if the adhesive 7 flows into the gap between the unit 1 and the electrode terminal 5, conductivity failure between the unit 1 and the electrode terminal 5 will not occur because the adhesive 7 has conductivity.

FIG. 2 shows a second embodiment of the electric double layer capacitor of the present invention. In this second embodiment, the lead portion 4b of the electrode terminal 4 on the case 2 side and the lead portion 5b of the electrode terminal 5 on the lid 3 side are shown in FIG.
are facing the same direction. Incidentally, in the first embodiment shown in FIG. 1, the lead portion 4b of the electrode terminal 4 on the case 2 side
The lead portion 5b of the electrode terminal 5 on the lid 3 side faces in the opposite direction.

Therefore, in the one shown in FIG. 2, the lower part of the lead part 4b of the electrode terminal 4 on the case 2 side is formed in a plate shape, and the current collecting part 4 disposed on the lower part of the plate and the inner surface of the bottom inside the case 2.
A nickel glue body 10 is arranged between the lead body 10 and the current collector 5a of the electrode terminal 5 on the M3 side, and a resin glue body 10 is disposed between the lead body 10 and the current collecting part 5a of the electrode terminal 5 on the M3 side. An insulator 11 is provided. Except for the above points, the electric double layer capacitor shown in FIG. This is the same as the case of the first embodiment shown in the figure.

In the electric double layer capacitor shown in FIG. 2 as well, the lid 3 is formed so that the upper surface of the outer circumferential portion 3b of the lid 3 is lower than the upper surface of the central portion 3c of the lid 3, and the application position of the adhesive 7 is adjusted. The adhesive 7 applied to the joint between the outer peripheral surface of the lid 3 and the inner peripheral surface of the case 2 at a lower level than the center portion 3C of the lid 3 is applied so as not to stay in the recess 3d formed on the outer peripheral portion 3b of the lid 3. In addition, the uncured adhesive 7 is prevented from flowing toward the center portion 3C of the lid 3 and staining the pressing member (not shown) or from adhering the pressing member and the lid 3. I have to.

FIG. 3 shows a third embodiment of the electric double layer capacitor of the present invention. In this third embodiment, the adhesive 7 is applied at a lower position than that of the first embodiment shown in FIG. , to prevent the uncured adhesive 7 from flowing more completely to the pressing member (not shown), and to prevent the pressing member from being contaminated by the adhesive 7 or from adhering the pressing member to the lid 3 due to the adhesive 7. This makes it possible to more completely prevent this. In other words, the lid 3 is formed so that the upper surface of the outer peripheral part 3b of the lid 3 is considerably lower than the upper surface of the central part 3C of the lid 3, and the coating is applied to the joint between the outer peripheral surface of the lid 3 and the inner peripheral surface of the case 2. A recess 3d in which the adhesive 7 is formed on the outer circumference 3b of the lid 3
The uncured adhesive 7 may flow to the center portion 3c of the lid 3 and stain the pressing member (not shown) or adhere the pressing member and the lid 3. I try not to have any. In addition, the adhesive 9 is applied at a low position to fill the gap between the lead portion 5b of the electrode terminal 5 and the hole in the lid 3. This prevents the liquid from flowing to the pressing member and contaminating the pressing member, or from adhering the pressing member to the lid 3.In this embodiment, the case 2 and the lid 3 are bonded together. As the adhesive 7, a cyanoacrylate instant adhesive is used for temporary fixing, and an epoxy resin adhesive is used for permanent fixing.Also, the adhesive 8.9 is the same as the adhesive 7 above. A cyanoacrylate-based instant adhesive is used for temporary fixing, and an epoxy resin-based adhesive is used for main fixing.However, as these adhesives 7 to 9, the first embodiment shown in FIG. Alternatively, as in the case of the second embodiment shown in FIG. 2, a conductive adhesive may be used.

As mentioned above, the application position of the adhesive 7 is lowered,
In addition, the application position of the adhesive 9 that fills the gap between the lead part 5b of the electrode terminal 5 and the hole of the lid 3 is also set low. The electric double layer capacitor shown in FIG. 3 is the same as the electric double layer capacitor shown in FIG.
Configuration of unit 1, materials of case 2 and lid 3, electrode terminal 4
．． The materials such as 5 are the same as those in the first embodiment shown in FIG.

〔Effect of the invention〕

As explained above, in the present invention, the lid is formed so that the upper surface of the outer peripheral part is lower than the upper surface of the central part, and the adhesive is applied at a lower position than the central part of the lid. The adhesive applied to the joint with the inner circumferential surface of the case remains in the recess formed on the outer circumference of the lid, and the uncured adhesive flows to the center of the lid and prevents the pressing member from getting dirty. This made it possible to prevent the pressing member and the lid from becoming glued together.

[Brief explanation of the drawing]

1 to 3 are cross-sectional views showing examples of the electric double layer capacitor of the present invention. FIG. 4 is an enlarged cross-sectional view of a unit used in an electric double layer capacitor. FIG. 5 is a sectional view showing the electric double layer capacitor shown in FIG. 1 during assembly. FIG. 6 is a sectional view showing a conventional electric double layer capacitor, and FIG. 7 is a sectional view showing the conventional electric double layer capacitor shown in FIG. 6 during assembly. 1...Unit, 2...Case, 2a...
Bottom, 3...Lid, 3a...Bottom surface, 3b...Outer periphery, 3c...Central part, 3d...Recess, 4-electrode terminal, 4a...-Collecting part, 5-electrode Terminal, 5a・
...Current collecting part, 7...Adhesive l...Unif Y 3 3a...Bottom surface 7''゛゛撞4f'1 9. 1--Usip V 2...Booth 2a/A-Shin 3-ku 3a... Lower surface 3b... External heat P Nu... Saifushu 4... Electrode place) 4a... East heavy wholesale 5... Electrode f4h 5a... Current collector P 781. 4 system Figure 7

Claims (2)

[Claims] (1) A plurality of electric double layer capacitor units 1 are stacked and housed in a case 2 made of an insulating material in which a plate-shaped current collecting part 4a of one electrode terminal 4 is arranged on the inner surface side of the bottom part 2a. A lid 3 made of an insulating material is fitted into the opening of the case 2, and a plate-shaped current collector 5a of the other electrode terminal 5 is arranged on the lower surface 3a.
This is an electric double layer capacitor in which the case 2 and the lid 3 are bonded together with an adhesive 7 while pressing the electric double layer capacitor unit 1 in the thickness direction with the lid 3. The upper surface is formed to be lower than the upper surface of the central portion 3c, and an adhesive 7 is applied to the joint between the inner circumferential surface of the case 2 and the outer circumferential surface of the lid 3, and the applied adhesive 7 is applied to the outer circumference of the lid 3. An electric double layer capacitor characterized in that a case 2 and a lid 3 are bonded together so that the liquid remains in a recess 3d formed on a portion 3b and does not flow to a central portion 3c of the lid 3. (2) The electric double layer capacitor according to claim 1, wherein the adhesive 7 is a conductive adhesive.