JP2629465B2 - Chip type electric double layer capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip-type electric double-layer capacitor, and more particularly to a casing structure of an electric double-layer capacitor for surface mounting.

[0002]

2. Description of the Related Art In recent years, there has been a remarkable reduction in the size and thickness of portable electronic devices such as headphone stereos and cordless telephones. Electric double-layer capacitors mounted on these electronic devices are also increasingly required to be smaller, thinner, and moreover surface-mounted, like other electronic components. Conventionally, as this type of electric double-layer capacitor, US Pat.
As disclosed in the specification of Japanese Patent No. 3, there is an apparatus utilizing contact between carbon powder and an electrolytic solution to generate an electric double layer. FIG. 7 is a sectional view of an electric double layer capacitor element (hereinafter, referred to as an element). In FIG. 7, 9
Is a conductive separator that is electron-conductive and ion-impermeable, 10 is a carbon paste electrode made of powdered activated carbon and an electrolyte solution, 11 is an ion-permeable and non-conductive, which is provided to prevent conduction between the carbon paste electrodes. The porous separator 9 having electron conductivity is a non-conductive gasket provided for holding the carbon paste electrode and shielding it from the outside.

FIG. 6 is a sectional view of a conventional chip type electric double layer capacitor. In FIG. 6, 6a is an element laminate in which the element 6 is laminated, and 4 and 5 are the lead terminal portions 4 respectively.
a and 5a having a first electrode plate and a second electrode plate,
Is a holding body having a holding portion 2a for pressing and holding the element laminate, 3 is an insulating layer for insulating the first and second electrode plates and the holding body, and 1 is an epoxy resin for exterior. And the like. In the conventional electric double layer capacitor, after the element laminate 6a is pressed and held by the holding body 2, it is immersed in an epoxy resin solution in order to prevent an electric short circuit on the side surface of the element laminate 6a, and then is kept at a constant temperature. It was heated and cured in the tank to provide the exterior.

[0004]

In this conventional chip type electric double layer capacitor, a first electrode plate, an element laminate, and a second electrode plate are arranged at predetermined positions on a holding member having a U-shaped cross section. Then, in order to form a holding portion by bending the tip of the holding body inward at a substantially right angle in a state where the element laminate is pressed through the first electrode plate, and immersing the holding body in an epoxy resin solution,
Due to the exterior method of heat curing, there are the following problems.

(1) The holding portion of the holding body returns in the direction of the arrow as shown in FIG. 6 (a) due to the springback of the molded material and the compressive stress of the element laminate. Due to the decrease, the equivalent series resistance of the electric double layer capacitor increases and the external dimensions increase.

(2) When the amount of the adhered resin increases, the outer diameter dimension increases, and at the same time, the dimensional variation increases.

(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 protrude from the same direction, the fixing stability is poor, and when vibration or the like is applied after soldering to the printed wiring board, there is a case where the lead terminal detaches from the printed wiring board. .

SUMMARY OF THE INVENTION It is an object of the present invention to prevent the holding portion of the holding body from returning due to the springback of the material and the compressive stress of the laminated body after molding, to reduce the equivalent series resistance of the capacitor, and to reduce the external dimensions. In addition, in resin molding, the thermal effect on the element laminate can be reduced,
It is another object of the present invention to provide a chip-type electric double-layer capacitor capable of reducing external dimensions, minimizing dimensional variations, smoothing the surface, enabling automatic mounting, and stabilizing fixation to a wiring board.

[0010]

According to the present invention, there is provided a chip-type electric double-layer capacitor comprising an electrode plate having a lead terminal projecting from an upper surface of a cylindrical electric double-layer capacitor in a laminating direction of an element laminate, and a lead from a lower surface. An electrode portion of a holding body in which an electrode portion having a protruding terminal portion and a holding portion for holding the element stack under pressure are arranged, and the holding body is substantially perpendicular to the electrode portion and substantially parallel to the electrode portion A through-hole window for avoiding contact with the element stack is formed at the center opposite to, and two opposing gaps whose opposing intervals are smaller than the outer diameter of the element stack, and the tip of the droop are formed substantially parallel to the electrode section. The device is characterized by comprising a holding portion, the holding portion pressurizing and holding the element laminate through the insulating layer and the electrode plate, and molding the periphery by injection of an insulating resin.

The chip type electric double layer capacitor of the present invention has a T-shaped cross-sectional projection between the hanging portion and the holding portion of the holding member, thermoplastic resin for the insulating resin for molding, and injection port for the insulating resin. It is characterized in that it is located substantially at the center on the cylindrical end face side of the element laminate.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings. 1A and 1B are explanatory views of a first embodiment of the present invention. FIG. 1A is a rear elevation view, FIG. 1B is a bottom view, and FIG. 1C is a front elevation view.
(D) is a top view, (e) is a right side view, (f) is a sectional view taken along line AA, (g) is a sectional view taken along line BB, and FIG. 2 is an exterior of the first embodiment of the present invention. (A) is a front elevational view in the front explanatory view,
(B) is a bottom view, (c) is a front elevation view, (d) is a top view, and (e) is a right side view. FIG. 3 shows the first embodiment of the present invention.
FIG. 4 is a front elevational view showing a state immediately before the exterior of the embodiment of FIG. 5, showing a state in which the element laminate is set in a molding die and an element laminate is pressed in the direction of an arrow via an electrode plate, and FIG. (A) is a component configuration diagram showing a vertical positional relationship between components in an assembled state before the exterior, (b) is an assembly state diagram before the exterior, and (c) is a mold metal just before the exterior. State diagram in which the element stack is pressed in the direction of the arrow through the electrode plate,
(D) is a state diagram after the mold exterior, and (e) is a state diagram of the finished product.

In FIGS. 1 and 2, first, the outer diameter is 8.4.
Six elements 6 each having a thickness of 0.7 mm and a thickness of 0.7 mm are laminated to obtain an element laminate 6a. As shown in FIGS. 2 and 4, the element laminate 6a has a hexagonal electrode portion 2c having a width of 9.8 mm and a protruding lead terminal portion 2b having a width of 2 mm, a thickness of 0.4 mm and a length of 7 mm. The interval between the bending points from the two opposing sides of the electrode portion 2c is less than 8 mm, and the electrode portion 2c is formed at an obtuse angle, and a through-hole window 2e having an end near the bending point near the electrode portion 2c is formed in the center. An iron / nickel alloy solder-plated having two hanging parts 2d and a holding part 2a formed just inward of the end of the through-hole window 2e at the tip of the hanging part 2d by approximately 90 ° from the hanging part 2d. It is arranged substantially at the center of the electrode portion 2c of the body 2.

Next, a width of 2 mm,
A lead terminal portion 7a having a thickness of 0.4 mm, a length of 7 mm, and a protruding lead terminal portion 7a having a distance between opposite sides of 9.8 mm and a hexagonal iron-nickel alloy plated with solder is used.
The projection direction of a is 180 ° with the lead terminal portion 2b of the holding body 2.
In the opposite direction, the electrode portion 2c of the holding body 2 and the electrode plate 7
Are arranged so that the end faces of the hexagons are flush with each other. Then, about 2 上下 vertically through the element laminate 6 a via the electrode plate 7.
Two drooping parts 2d under a pressure of 0 kg / cm ²
Is bent substantially at right angles to the electrode portion 2c to remove the pressure on the element laminate 6a. In addition, the element laminate 6a is about 20 kg / c.
It is deformed to a thickness of 3.0 mm and a maximum outer diameter of about 9.4 mm by pressurization of m ² . In a state in which the element stack 6a is pressed and held by the holding portion 2a, the holding portion 2a and the hanging portion 2d have a T-shaped projection shape in the cross-sectional direction, and the lead terminals 2b,
Except for the central portion parallel to 7a, the holding member 2 and the electrode plate 7 have substantially the same shape, so that the interval between them is 9.8.
A chip-type electric double-layer capacitor (hereinafter, referred to as a semi-finished product) having a hexagonal shape of 4.2 mm and a thickness of 4.2 mm as shown in FIG. 5B is obtained.

Next, the semi-finished product is 10.5 mm long and 1 mm wide.
The electrode plate 7 side is set in a mold having a hollow portion of 0.5 mm and a thickness of 5 mm with the electrode plate 7 side facing up.
As shown in FIGS. 3 and 4 (c), a pressure of 20 kg / cm ² is applied to each of the four mold pins (not shown) to compress the element laminated body 6a through the holding member 2a. A gap is provided between the electrode plate 7 and a thermoplastic and high heat-resistant insulating resin 1 such as PPS (polyphenylene sulfide). It is injected and molded from the resin injection gate 1c. The insulating resin injection gate 1c is generally called a pin point gate, and is automatically broken from the root on the product side when the upper and lower molds at the time of completion of molding are opened. Further, the electrode plate side hole 1a and the holding body side hole 1b are traces of the mold pins, and the element laminate 6a is compressed via the electrode plate 7 to fix a semi-finished product during molding. A gap is provided between the holding portion 2a and the electrode plate 7 to inject the insulating resin 1 to insulate the two and to reduce the equivalent series resistance of the electric double layer capacitor. Thus, a chip type electric double capacitor according to the first embodiment of the present invention was obtained.

FIG. 5 is a drawing for explaining a second embodiment of the present invention, and is a cross-sectional view corresponding to line BB in the top view shown in FIG. 1 (b). The only difference is that an insulating layer 3 made of polyimide or the like is previously coated or placed on the entire surface of the electrode plate 2 on the side of the holding portion 2a except for 7a. As described above, even if the insulating resin 1 is not completely injected into the gap between the holding portion 2a and the electrode plate 7, the insulation between the holding portion 2a and the electrode plate 7 can be reliably ensured.

Next, Table 1 shows the average value and the variation of the product dimensions of each of 100 chip-type electric double layer capacitors according to the embodiment of the present invention and the conventional example.

[0018]

As is apparent from Table 1, the size of the electric double layer capacitor of the embodiment of the present invention was small, and the variation was reduced to about 1/4.

[0020]

As described above, the present invention has the following effects.

(1) The electrode portion and the holding portion are integrated and the interval between two opposing hanging portions is made smaller than the outer diameter of the element laminate by forming a through-hole window. Since the projected shape in the cross-sectional direction is T-shaped, the holding portion does not return due to the springback of the material and the compressive stress of the element laminate after molding. Further, since the hanging portion is inside the tangent to the outer diameter of the element laminate, the equivalent series resistance of the electric double layer capacitor can be reduced, and the outer dimensions can be reduced.

(2) Since the thermoplastic resin is injected from the central portion on the cylindrical end surface side of the element laminate by a molding process, the heat influence on the element laminate is small, and the semi-finished product is fixed in the mold. The amount of the insulating resin to be held and injected is also controlled by the mold, so that the external dimensions can be reduced and the dimensional variation can be reduced. In addition, since the exterior surface is smooth, it can be automatically mounted on printed wiring by a vacuum suction method.
Further, the projecting directions of the two lead terminal portions are set to 180
° Since it can be made in the opposite direction, the stability of fixing to the printed wiring board is improved.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a first embodiment of the present invention, wherein (a) is a rear elevational view, (b) is a bottom elevational view, (c) is a front elevational view,
(D) is a top view, (e) is a right side view, (f) is an AA sectional view, and (g) is a BB sectional view.

FIGS. 2A and 2B are explanatory views of the first embodiment of the present invention before the exterior, where FIG. 2A is a rear elevation view, FIG. 2B is a bottom view, FIG. 2C is a front elevation view, and FIG. (E) is a right side view.

FIG. 3 is a state diagram immediately before the exterior of the first embodiment of the present invention,
FIG. 4 is a front elevational view showing a state where the device is set in a mold and an element laminate is pressed in the direction of an arrow via an electrode plate.

FIGS. 4A and 4B are perspective views of the first embodiment of the present invention, wherein FIG. 4A is a component configuration diagram showing a vertical positional relationship between components in an assembled state before exterior, FIG. (C) is a state diagram in which the device laminate is set in a mold just before the exterior and the element laminate is pressed in the direction of the arrow via an electrode plate, (d) is a state diagram after the exterior of the mold, and (e) is a completed product. It is a state diagram.

FIG. 5 is a cross-sectional view corresponding to line BB of FIG. 1D of the second embodiment of the present invention.

6A and 6B are explanatory diagrams of an example of a conventional chip-type electric double layer capacitor, in which FIG. 6A is a cross-sectional view taken along line AA, and FIG. 6B is a side view.

FIG. 7 is a sectional view of an electric double layer capacitor element.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 insulating resin 1a electrode plate side hole 1b holding body side hole 1c insulating resin injection gate 1d lead housing groove 2 holding body 2a holding part 2b holding terminal 2c electrode part 2d hanging part 2e through-hole window 3 insulating layer 4 First electrode plate 4a Lead terminal portion of first electrode plate 5 Second electrode plate 5a Lead terminal portion of second electrode plate 6 Element 6a Element laminate 7 Electrode plate 7a Lead terminal portion of electrode plate 8 Conductivity Separator 9 Non-conductive gasket 10 Carbon paste electrode 11 Porous separator

Claims (4)

(57) [Claims] 1. An electrode plate having a lead terminal protruding from the upper surface in the stacking direction of an element laminate of a cylindrical electric double layer capacitor, and an electrode and an element laminate having a lead terminal protruding from the lower surface are pressed. An electrode portion of a holding body in which a holding portion to be held is integrated is disposed, and the holding body avoids contact between the electrode portion and a central portion of the electrode portion substantially perpendicular to the electrode portion and substantially parallel to each other. It consists of two hanging parts which form a through-hole window and whose facing distance is smaller than the outer diameter of the element laminate, and a holding part whose tip is formed substantially in parallel with the electrode part. The insulating part and the electrode are formed by the holding part. A chip-type electric double-layer capacitor characterized in that an element laminate is pressurized and held via a plate, and the periphery of the element laminate is molded by injection of an insulating resin. 2. The chip-type electric double-layer capacitor according to claim 1, wherein a projected shape of the hanging portion and the holding portion in a cross-sectional direction is T-shaped. 3. The chip-type electric double layer capacitor according to claim 1, wherein said insulating resin is a thermoplastic resin. 4. The chip-type electric double-layer capacitor according to claim 1, wherein the injection port of the insulating resin is located substantially at the center on the cylindrical end face side of the element laminate.