JPH05315190A - Chip type electric double layer capacitor - Google Patents

Abstract

PURPOSE:To reduce the size and an equivalent series resistance and to increase a mounting stability by locating rectangular element laminated bodies in parallel wherein an upper and a lower conductive separator which connect elements are united into one body and by coating insulating resin on the element laminated bodies with the element laminated bodies being applied with pressure and held through a termination electrode plate and an intermediate electrode plate. CONSTITUTION:Three elements 9 are laminated with one conductive separator put between each two elements for connecting the elements to obtain an element laminated body 9a. The element laminated body 9a is so located that the whole surface of one face of the element 9 in the lamination direction may be brought into contact with two intermediate electrode plates 8. Nextly, a pair of termination electrode plates 6, 7 which have a projecting lead terminal 6a, 7a may be brought into contact with the whole surface of the other face of the element laminated body 9a in the lamination direction. Then, calking is conducted so that a relative positional relation among the termination electrode plates 6, 7, the intermediate electrode plates 8, and the element laminated body 9a may be maintained. After that, the element laminated body 9a is compressed with upper and lower die pins, each four, through the termination electrode plates 6, 7, and the intermediate electrode plate 8 and insulating resin is put into every space in a die.

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 an element and a casing structure of a chip type electric double layer capacitor which is compatible with surface mounting.

[0002]

2. Description of the Related Art In recent years, there have been remarkable reductions in the size and thickness of portable electronic devices such as headphone stereos and cordless phones. Electric double-layer capacitors mounted on these electronic devices are becoming smaller and thinner like other electronic parts, and moreover, the demand for surface mounting is increasing. Conventionally,
As an electric double layer capacitor of this type, one of means for obtaining a large capacity capacitor is disclosed in US Pat. No. 35369.
As disclosed in Japanese Patent No. 63, there is one utilizing contact between carbon powder and an electrolytic solution 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, 10 is an electrically conductive and ion-impermeable conductive separator, 12 is a carbon paste electrode made of powdered activated carbon and an electrolyte solution which constitutes a polarizable electrode, and 13 is a conduction between the carbon paste electrodes. An ion-permeable and non-electroconductive porous separator 11 is provided to prevent the above phenomenon, and a non-conductive gasket 11 is provided to hold the carbon paste electrode and shield it from the outside. FIG. 4 is a right side view of a conventional chip type electric double layer capacitor and a cross-sectional view taken along the line AA.

In FIG. 4, reference numeral 9a denotes an element laminated body in which the element 9 is laminated, and 4 and 5 lead terminal portions 4a and 5 respectively.
a first electrode plate and a second electrode plate having a, 2 is a holding body 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 holding body, and 1 is an insulating resin such as an epoxy resin for exterior packaging. In the conventional electric double layer capacitor, after holding the element laminate 9a by the holding body 2 under pressure, it is dipped in a solution of epoxy resin in order to prevent an electrical short circuit on the side surface of the element laminate 9a, and then in a thermostatic chamber. It was heat-cured and was used for exterior packaging.

[0005]

In this conventional chip-type electric double layer capacitor, a first electrode plate, a device laminate and a second electrode plate are arranged at predetermined positions 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 (b) due to the springback of the material after molding and the compressive stress of the element laminated body, so that the holding pressure on the element laminated body reduces the electric The double-layer capacitor has an increased equivalent series resistance and an increased external dimension. (2) When the amount of adhered resin increases, the outer dimension increases and the dimensional variation increases at the same time. (3) Since the exterior surface is uneven, it cannot be automatically mounted on a printed wiring board by the vacuum suction method. (4) Since the two lead terminal portions project from the same direction, the fixation stability is poor, and when vibration 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 stable mounting.

[0007]

In a chip type electric double layer capacitor of the present invention, a pair of polarizable electrodes in which activated carbon is impregnated with an electrolytic solution are opposed to each other via an electronically insulating and ion permeable porous separator. , Electronically conductive, ion-impermeable conductive separator and non-conductive gasket,
Two rectangular element laminates that connect a plurality of the elements holding the polarizable electrodes in series are arranged in parallel, and the two element laminates are electrically connected in series on one surface of the element laminate in the stacking direction. The intermediate electrode plate, which is electrically independent on the other side,
The surroundings are covered with an insulating resin in order to pressurize and hold the two element laminated bodies through a pair of terminal electrode plates connected to lead terminals that are electrically drawn out to the outside, and the space between each element of the element laminated bodies is It is characterized in that the conductive separators to be connected are integrated vertically. Further, it is characterized in that the conductive separators of the two element laminated bodies in contact with the intermediate electrode plate are integrated left and right, and the insulating resin is injected from the insulating resin injection gate provided at the center of the end electrode plate side. .

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. 1A and 1B are a top view, a sectional view taken along line AA in FIG. 1D, a bottom view and a side view, respectively, of a first embodiment of the present invention.
FIG. 2 is a right side view of the electric double layer capacitor element according to the first embodiment of the present invention and a sectional view taken along the line AA.

In FIG. 1 and FIG. 2, first, a conductive separator 10 is interposed between the respective elements 9 and three elements 9 for connecting the respective elements 9 are stacked, and a width of 3.8 mm and a length of 8 are obtained. An element stack 9a having a thickness of 0.0 mm and a thickness of 2.9 mm is obtained.
In the element stack 9a, one side in the stacking direction of the element 9 is entirely in contact with the intermediate electrode plate 8 formed by solder-plating two pieces of iron-nickel alloy with a side of 8 mm and a thickness of 0.4 mm.
In addition, the two element laminated bodies 9a are arranged so that the distance between them is about 0.4 mm. Next, a width of 3.0 mm, a thickness of 0.4 mm, and a length of 5.0 m are provided on the other surface of the element stack body 9a in the stacking direction.
The width of the lead terminals 6a, 7a of m is 3.8 mm,
A pair of terminal electrode plates 6 and 7 each having a length of 8.0 mm and having an iron / nickel alloy plated with solder are arranged so as to be in full contact. Termination electrode plates 6, 7, intermediate electrode plate 8, element stack 9
After caulking so as to maintain the relative positional relationship of a, and temporarily fixing it by a known means such as welding, the intermediate electrode plate 8 side is placed downward in a mold having a hollow portion of 10 mm in length, 10 mm in width, and 4.1 mm in thickness. Then, the element laminate 9a is compressed to a thickness of about 80% of that when no load is applied by using four upper and lower mold pins (not shown) through the terminal electrode plates 6 and 7 and the intermediate electrode plate 8. , P
A thermoplastic and highly heat-resistant insulating resin 1 such as PS (polyphenylene sulfide) is filled into the entire gap in the mold to form the terminal electrode plate 6,
It is injected from the insulating resin injection gate 1c at the center of the upper part on the 7 side and molded. The insulating resin injection gate 1c is generally 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. Also,
Since the terminal electrode plate side hole portion 1a and the intermediate electrode plate side hole portion 1b are compressed to a thickness of about 80% of no load after completion of molding, the element laminated body 9a is compressed after the mold pin. The electric double layer capacitor has a low transmission series resistance. next,
The lead terminals 6a and 7a are molded into a predetermined shape using a lead molding die. FIG. 1 shows an example in which the lead terminals 6a and 7a are molded into a J-bend lead type in which the lead terminals capable of high-density mounting are bent inward as compared with the gull-wing lead type (not shown) in which the lead terminals are bent outward. By accommodating the leading end portions of the lead terminals 6a and 7a in the lead accommodating groove 1d provided in the insulating resin 1 on the lower surface of the product, an increase in the size of the product in the thickness direction is suppressed and rattling occurs when the product is mounted on a printed wiring board. Becomes smaller. As described above, the chip type electric double layer capacitor of the first embodiment of the present invention was obtained.

FIG. 3 is a drawing for explaining the second embodiment of the present invention and corresponds to FIG. 2 (b). It differs from the first embodiment only in that the conductive separators of the two element laminated bodies which are in contact with the intermediate electrode plate are integrated left and right. for that reason,
The two element laminated bodies 9a can be simultaneously positioned and handled, the two element laminated bodies 9a can be simultaneously positioned and handled, and the distance between the two element laminated bodies 9a can be kept constant. As a result, it becomes easy to form the element 9 and the element laminated body 9a and to assemble the terminal electrodes 6 and 7, the intermediate electrode plate 8 and the like.

Next, Table 1 shows the measurement results of 100 dimensional values of each of the chip type electric double layer capacitors of the embodiment of the present invention and the conventional example and their variations.

[0012]

[Table 1]

As is apparent from Table 1, the electric double layer capacitors according to the examples of the present invention were small in size and the variation could be reduced to about 1/4.

[0014]

As described above, the present invention has the following effects. (1) Since the electric double layer capacitor element is rectangular, including the filling portion of the carbon paste electrode provided in the non-conductive gasket, the area formed by the substantially square shape and the area formed by the inscribed circle of the square shape. The volumetric efficiency of the electric double layer capacitor element is improved by the amount of the ratio and the outer dimension of the element can be reduced. Furthermore, 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 of the conventional one, and the conductive separators connecting the respective elements are vertically integrated, The thickness of the element stack can be reduced. In addition, the element laminated body is molded under pressure, and the insulating resin maintains the pressure during molding even after the molding is completed, so the equivalent series resistance of the electric double layer capacitor is reduced. In addition, the external dimensions can be reduced. (2) By integrating left and right conductive separators of two element laminates that are in contact with the intermediate electrode plate, the two element laminates are connected and the distance between the two element laminates is made constant. Since this can be maintained, it is possible to prevent a short circuit due to contact between the element laminated bodies and an exposure of the element laminated body from the insulating resin surface due to separation. Further, since the two element laminated bodies can be positioned and handled at the same time, the elements and the element laminated bodies can be easily formed and assembled. (3) Since the insulating resin is injected between the two element laminated bodies due to the exterior method by molding in which the thermoplastic insulating resin is injected from the central portion on the side of the terminal electrode plate, the entire gap in the mold is obtained. Since the resin is injected into the structure, it is possible to prevent a short circuit due to contact between the two element laminated bodies. Further, since the element laminate, the terminal electrode plate, and the intermediate electrode plate are held at predetermined positions in the mold, and the amount of the insulating resin to be injected is also controlled by the mold, it is possible to reduce the outer dimensions and at the same time reduce the dimensional variation. . Further, since the exterior surface is smooth, it can be automatically mounted on the printed wiring board by vacuum suction. Furthermore, since the protruding directions of the lead terminals connected to the two termination electrode plates can be opposite to each other by 180 °, the fixing stability to the printed wiring board is improved.

[Brief description of drawings]

FIG. 1 is a top view of a chip type electric double layer capacitor of a first embodiment of the present invention, an AA sectional view of FIG. 1 (d), a bottom view and a right side view.

2 is a right side view of the element stack body shown in FIG. 1 and a cross-sectional view taken along the line AA. FIG.

FIG. 3 is a sectional view of an element laminate of a chip-type electric double layer capacitor according to a second embodiment of the present invention.

FIG. 4 is a right side view of a conventional chip type electric double layer capacitor and a cross-sectional view taken along the line AA.

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

[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 1d Lead accommodating groove 2 Clamp 2a Holding part 3 Insulating layer 4 First electrode plate 4a First electrode plate lead 5 Second electrode plate 5a Lead terminal of second electrode plate 6 First terminal electrode plate 6a Lead terminal of first terminal electrode plate 7 Second terminal electrode plate 8 Intermediate electrode plate 9 Element 9a Element laminate 10 Conductivity Separator 11 Non-conductive gasket 12 Carbon paste electrode 13 Porous separator

Claims (3)

[Claims] 1. A pair of polarizable electrodes, in which activated carbon is impregnated with an electrolytic solution, are opposed to each other via an electronically insulating and ion-permeable porous separator, and an electrically conductive and ion-impermeable conductive separator and a non-conductive separator are provided. Two rectangular element laminates that connect a plurality of elements holding the polarizable electrodes in series by a conductive gasket are arranged in parallel, and two element laminates are provided on one surface of the element laminate in the laminating direction. An intermediate electrode plate that is electrically connected in series, each of which is electrically independent on the other side, and two element laminated bodies are added through a pair of terminal electrode plates that are connected to lead terminals that electrically lead to the outside. A chip-type electric double layer capacitor, characterized in that the periphery thereof is covered with an insulating resin so as to be pressed and held, and conductive separators for connecting the respective elements of the element laminate are vertically integrated. 2. The chip type electric double layer capacitor according to claim 1, wherein the conductive separators of the two element laminated bodies which are in contact with the intermediate electrode plate are integrated left and right. 3. The chip type electric double layer capacitor according to claim 1, wherein the insulating resin is injected from an insulating resin injection gate provided at the center of the terminal electrode plate side.