JPH065469A - Chip type electric double layer capacitor - Google Patents

Abstract

PURPOSE:To obtain a small-sized chip type electric double layer capacitor excellent in packaging stability wherein the equivalent series resistance is small and the automatic mounting on a printed wiring board is possible. CONSTITUTION:Two element laminates 10a of rectangular electric double layer capacitors are arranged in parallel. The element laminates 10a are pressed and retained via terminal electrode plates 7, 8 and an intermediate electrode plate 9. In this state, the periphery of the laminates is covered with insulating resin 1. Thereby the volume efficiency is improved, and the external size of the element can be reduced. Since the two element laminates 10a are arranged in parallel, the number of element lamination layers of one element laminate 10a can be reduced to 1/2 as compared with the conventional case, and the element laminate can be thinned. Further, since the molding is performed in the pressed state, the equivalent series resistance, the external size, and the dimensional irregularity can be reduced. The automatic mounting is enabled by vacuum suction.

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 casing structure for a chip type electric double layer capacitor which is compatible with surface mounting.

[0002]

2. Description of the Related Art In recent years, portable electronic devices such as headphone stereos and cordless phones have been remarkably reduced in size and thickness. Electric double-layer capacitors mounted on these electronic devices are becoming smaller and thinner like other electronic components, and there is a growing demand for surface mounting. Conventionally,
As this kind of electric double layer capacitor, one of means for obtaining a large capacity capacitor is disclosed in US Pat. No. 35369.
As disclosed in Japanese Patent No. 63, 63, there is a method in which a carbon powder and an electrolytic solution are brought into contact with each other to generate an electric double layer. FIG. 5 is a sectional view of a cylindrical electric double layer capacitor element (hereinafter referred to as an element). In FIG. 5, 11 is an electrically conductive and ion-impermeable conductive separator, 13 is a carbon paste electrode composed of powdered activated carbon and an electrolyte solution, and 14 is an ion permeation layer provided to prevent conduction between the carbon paste electrodes. The porous separator 12, which is electrically conductive and has non-electron conductivity, is a non-conductive gasket provided to hold the carbon paste electrode and to shield it from the outside.

FIG. 4 is a sectional view of a conventional chip type electric double layer capacitor. In FIG. 4, 10a is an element laminated body in which the elements 10 are laminated, and 4 and 5 are lead terminal portions 4 respectively.
a first electrode plate and a second electrode plate having a and 5a, 2
Is a holder having a holding portion 2a for pressing and holding the element stack, 3 is an insulating layer for insulating the first and second electrode plates from the holder, and 1 is an epoxy resin for exterior Is an insulating resin. In the conventional electric double layer, the element stack 10a is pressed and held by the holding body 2 and then the element stack 10a is pressed.
In order to prevent an electrical short circuit on the side surface of the device, it was dipped in a solution of an epoxy resin and then pressure-cured in a high temperature tank to carry out exterior packaging.

[0004]

In this conventional chip-type electric double layer capacitor, the first electrode plate, the element stack, and the second electrode plate are arranged in a predetermined position on a holding body having a U-shaped cross section. Then, in order to form the holding portion by bending the tip of the holding body inwardly at a substantially right angle in a state in which the element laminated body is pressed through the first electrode plate, and after immersing in the epoxy resin solution,
Due to the exterior method of curing by heating, there were the following problems. (1) The holding portion of the holding body returns in the direction of the arrow as shown in FIG. 4 (a) due to the springback of the material after molding and the compressive stress of the element laminated body. The equivalent series resistance of the double-layer capacitor increases and the external dimensions increase. (2) When the amount of adhered resin increases, the external dimensions increase and the dimensional variations increase at the same time. (3) Since the exterior surface is uneven, automatic mounting on a printed wiring board by a vacuum suction method is impossible. (4) Since the two lead terminal portions project from the same direction, the fixation stability is poor, and when vibration or the like is applied after soldering to the printed wiring board, the lead terminal portion may be separated from the printed wiring board.

An object of the present invention is to provide a chip type electric double layer capacitor which is small in size, has a low equivalent series resistance, can be automatically mounted on a printed wiring board, and has good mounting stability.

[0006]

A chip type electric double layer capacitor of the present invention comprises two rectangular electric double layer capacitor element laminated bodies arranged in parallel and a lower surface of the element laminated body in the laminating direction in contact with each other. An intermediate electrode plate that electrically connects the individual element laminates in series, and a pair of terminal electrode plates that are connected to the upper surface of the element laminate independently of each other and have lead terminals that are electrically drawn to the outside. , The terminal electrode plate and an insulating resin which covers the periphery of the two element laminated bodies via the intermediate electrode plate so as to pressurize and hold them.

By dividing at least one lead terminal of the terminal electrode plate into two, it is possible to obtain the effect of stabilizing the mounting on the printed wiring board and preventing abnormalities in the reverse mounting.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. FIG. 1A is a top view of an embodiment of the present invention, and FIG.
Is a sectional view taken along the line A-A in (d), (c) is a bottom view, and FIG. 3 shows (a) of the electric double-layer capacitor element of the present invention taken along line A- of (b).
A sectional view, (b) is a right side view.

In FIGS. 1 and 3, first, the width is 3.8 m.
Three elements 10 each having m, a length of 8.0 mm, and a thickness of 1.1 mm are laminated to obtain an element laminated body 10a. Element stack 10a
Are placed on an intermediate electrode plate 9 which is a square having a side of 8 mm and a thickness of 0.4 mm and which is solder-plated on an iron-nickel alloy. Next, on the upper surface of the element laminate 10a, a width of 3.0 m
m, thickness 0.4 mm, length 5 mm lead terminals 7a, 8
A pair of terminal electrode plates 7, 8 obtained by solder-plating an iron-nickel alloy having a width of 3.8 mm and a length of 8.0 mm, in which a is projected, are fitted to the upper surfaces of the two element laminated bodies 10a. Deploy. After fixing the terminal electrode plates 7 and 8, the intermediate electrode plate 9, and the element laminated body 10a by a known means such as caulking so as to maintain the relative positional relationship, a hollow portion having a length of 10 mm, a width of 10 mm, and a thickness of 4.5 mm. The intermediate electrode plate 9 side is set up in a mold having the above, and the element laminated body 10a is inserted with the upper and lower four mold pins (not shown) through the terminal electrode plates 7 and 8 and the intermediate electrode plate 9. It is compressed to a thickness of about 80% of that when no load is applied, and thermoplastic and highly heat-resistant insulating resin 1 such as PPS (polyphenylene sulfide) is filled into the entire gap in the mold to insulate the upper center of the intermediate electrode plate 9. It is injected from the resin injection gate 1c and molded. The insulating resin injection gate 1c is commonly called a pin point gate, and is automatically cut from the root of the product side when the mold is opened at the time of completion of molding.
In addition, the terminal electrode plate side hole 1a and the intermediate electrode plate side hole 1
b is a mark of the mold pin. Since the element laminated body 10a is compressed to a thickness of about 80% after no molding is performed, the electric double layer capacitor has a low equivalent series resistance. As described above, the electric double layer capacitor of the first embodiment of the present invention was obtained.

FIG. 2 is a drawing for explaining another embodiment of the present invention and is a bottom view corresponding to FIG. 1 (c). It differs from the first embodiment only in that the lead terminal 8a of the second terminal electrode plate is divided into two. According to the second embodiment, since the lead terminals are three terminals, the mounting stability on the printed wiring board is improved by supporting three points, and the printed wiring board is mounted when the lead terminals 7a and 8a are reversely mounted. Since it does not match the electrode portion configured in (3), soldering becomes impossible and abnormal products can be easily eliminated.

Next, as quantitative numerical data in addition to the qualitative effect, as shown in Tables 1 (a) and 1 (b), 100 chips each of the chip type electric double layer capacitors of the embodiment of the present invention and the conventional example are shown. The average value and variation of product dimensions are shown. As is clear from Table 1, the electric double layer capacitor of the present invention has a small size and the variation can be reduced to about 1/4.

[0012]

[Table 1]

[0013]

As described above, the present invention has the following effects. (1) Since the electric double layer capacitor element including the filling portion of the carbon paste electrode provided on the non-conductive gasket is rectangular, the area formed by the substantially regular square and the area formed by the inscribed circle of the regular square. The volumetric efficiency of the electric double layer capacitor element is improved by the ratio of the ratio to and the external dimension of the element can be reduced. Further, since the two element laminated bodies are arranged in parallel, the number of laminated elements of one element laminated body can be reduced to half that of the conventional one, so that the thickness of the element laminated body can be reduced.

Further, since the element laminated body is molded under pressure, and the insulating resin maintains the pressure during molding, the equivalent series resistance of the electric double layer capacitor is maintained. Can be made smaller and the external dimensions can be made smaller. (2) Due to the exterior method by molding in which the element laminate is injected with the thermoplastic resin from the central portion on the end face side of the cylinder, the heat influence on the element laminate is small, and the element laminate, the terminal electrode plate, and the intermediate electrode plate are formed. Since the amount of the insulating resin to be held at a predetermined position in the mold is also controlled by the mold, it is possible to reduce the outer dimension and the dimension variation. Further, since the exterior surface is smooth, it can be automatically mounted on the printed wiring board by vacuum suction. Further, since the lead terminals that are connected to the two terminal electrode plates can be projected in opposite directions to each other by 180 °, the fixing stability to the printed wiring board is improved. In the case of the second embodiment, since the two terminals are supported by the three terminals, the fixing stability to the printed wiring board is further improved.

[Brief description of drawings]

FIG. 1A is a top view of a chip type electric double layer capacitor according to an embodiment of the present invention, FIG. 1B is a sectional view taken along line AA, and FIG.
Is a bottom view, and (d) is a right side view.

FIG. 2 is a bottom view of another embodiment of the present invention.

3 (a) is a sectional view taken along the line AA of the chip type electric double layer capacitor element of the embodiment of the present invention shown in FIG. 1, and FIG. 3 (b) is a right side view.

FIG. 4 (a) of a conventional chip type electric double layer capacitor
Is a sectional view taken along the line AA, and (b) is a right side view.

FIG. 5 is a cross-sectional view of a conventional electric double layer capacitor element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Insulating resin 1a Termination electrode plate side hole 1b Intermediate electrode plate side hole 1c Insulating resin injection gate 2 Holding body 2a Holding part 3 Insulating layer 4 First electrode plate 4a First electrode plate lead terminal 5 Second Electrode plate 5a Lead terminal for second electrode plate 7 First terminal electrode plate 7a Lead terminal for first terminal electrode plate 8 Second terminal electrode plate 8a Lead terminal for second terminal electrode plate 9 Intermediate electrode plate 10 Element 10a Element laminate 11 Conductive separator 12 Non-conductive gasket 13 Carbon paste electrode 14 Porous separator

Claims (2)

[Claims] 1. A rectangular electric double layer capacitor element laminated body arranged in parallel, and an intermediate electrode plate which is in contact with the lower surface of the element laminated body in the laminating direction and electrically connects two element laminated bodies in series. And a pair of terminal electrode plates, each of which is electrically independently contacted with the upper surface of the element laminate and connected with a lead terminal that is electrically drawn to the outside, and two terminal electrode plates through the terminal electrode plate and the intermediate electrode plate. 2. An electric double layer capacitor of chip type, characterized in that it has an insulating resin whose periphery is covered so as to hold the element laminated body under pressure. 2. The chip type electric double layer capacitor according to claim 1, wherein at least one lead terminal of the terminal electrode plate on one side is divided into two.