JPH08203780A - Chip type aluminum electrolytic capacitor - Google Patents

Abstract

PURPOSE: To enable stable mounting by soldering by constituting an inner capacity of a bottomed case by adding a volume of a gap part provided inside the bottomed case to the total of an actual volume of each of a lead member, an anode foil, a cathode foil, a separator, a stopping tape of the end of winding and electrolytic solution. CONSTITUTION: In a capacitor element 11, an anode foil 13 and a cathode foil 14 whereto a lead member 12 is connected are wound interposing a separator 15 therebetween, and the end of winding is stopped by a stopping tape 16. The element 11 is impregnated with electrolytic solution 17 and is contained inside the bottomed case 18, and a sealing body 19 wherethrough the lead member 12 passes is mounted on an opening part of the case 18. The electrolytic solution 17 is sealed in the case 18 by adjusting an impregnation amount thereof which is the sum of a volume of the gap part 20 in addition to an actual volume of each of the member 12, the anode foil 13, the cathode foil 14, the separator 15, the tape 16 and the electrolytic solution 17. A volume of the gap part 20 is made at least 5% of a volume enclosed with the case 18 and an insulation board 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type aluminum electrolytic capacitor used in various electronic devices.

[0002]

2. Description of the Related Art With the recent miniaturization, thinning and multi-functionalization of electronic equipment, the density of electronic circuits is increasing, and electronic parts are also becoming smaller, lower in height and surface mounted.

The conventional chip type aluminum electrolytic capacitor is
For example, as shown in Japanese Patent Laid-Open No. 59-212114, that is, as shown in the cross section of FIG. 4, an anode foil 2 and a cathode foil 3 to which a lead member 1 is connected, with a separator 4 interposed therebetween. The capacitor element 6 wound and wound with the tape 5 is impregnated with the electrolytic solution 7 and housed in the bottomed case 8, and the lead member 1 is provided in the opening of the bottomed case 8. A sealing body 9 that penetrates is attached and sealed, and the lead member 1 is further attached to the bottomed case 8
Of the lead member 1 is bent so that it is housed in the recess 10a provided on the outer surface of the insulating plate 10. It was

[0004]

However, the chip type aluminum electrolytic capacitor shown in FIG. 4 is exposed to a high temperature of 180 ° C. to 220 ° C. during reflow soldering when it is mounted on a printed circuit board of an electronic device. The electrolytic solution expands in volume, and this volume expansion compresses the internal space of the bottomed case 8 to increase the internal pressure, which causes the sealing body 9 to expand and deform, which causes the insulating plate 10 to expand. There was a warp under pressure. When this warpage occurs, the surface mounting surface of the outer surface of the insulating plate 10 is bent, so that the aluminum electrolytic capacitor is mounted in an inclined state during reflow soldering when mounting on a printed circuit board of an electronic device. Had.

The present invention solves the above-mentioned problems of the prior art. A chip which can be mounted on a printed circuit board of an electronic device by soldering in a stable state without tilting the chip type aluminum electrolytic capacitor. The purpose is to provide a shaped aluminum electrolytic capacitor.

[0006]

In order to achieve the above-mentioned object, a chip type aluminum electrolytic capacitor of the present invention has an anode foil and a cathode foil to which lead members are connected, wound with a separator interposed therebetween, and wound. A capacitor element wound with a stop tape, an electrolytic solution impregnated in the capacitor element, a bottomed case for housing the capacitor element, a sealing body for sealing the opening of the bottomed case, and the An insulating plate disposed so as to contact the end surface of the opening of the bottom case, and having the lead member facing the outer surface,
The inner volume of the bottomed case, the lead member, the anode foil,
The cathode foil, the separator, the winding tape, and the electrolytic solution are added together, and the volume of the void portion of 5% or more provided in the bottomed case is added.

[0007]

According to the chip type aluminum electrolytic capacitor having the above structure, the inner volume of the bottomed case is made to be the sum of the substantial volumes of the lead member, the anode foil, the cathode foil, the separator, the winding tape and the electrolytic solution. Since it is configured to add the volume of the void provided in the bottomed case,
Even if the electrolytic solution expands in volume when soldering when it is mounted on the printed circuit board of an electronic device, the increase in the internal pressure of the bottomed case due to the expansion should be reduced by the void provided in the bottomed case. As a result, the sealing body does not swell and deform, so there is no possibility that the insulating plate will be pressed and warped, and as a result, mounting by soldering on the printed circuit board of the electronic device The chip type aluminum electrolytic capacitor can be operated in a stable state without tilting.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a chip-type aluminum electrolytic capacitor according to an embodiment of the present invention. In FIG. 1, 11 is a capacitor element.
1 is an anode foil 13 and a cathode foil 14 to which lead members 12 are connected.
Are wound with a separator 15 interposed therebetween, and are wound with a winding stop tape 16, and an electrolytic solution 17 is applied to the capacitor element 11.
And is housed in the bottomed case 18, and the lead member 12 is placed in the opening of the bottomed case 18.
By mounting a sealing body 19 penetrating therethrough and adjusting the impregnation amount of the electrolytic solution 17, the lead member 12, the anode foil 13, the cathode foil 14, the separator 15, the winding stop tape 16 are provided in the bottomed case 18. , The total volume of each of the electrolytic solutions 17 is added to the total volume of the voids 20 provided in the bottomed case 18, and the lead member 12 is sealed. Is penetrated through the insulating plate 21 arranged so as to abut the end face of the opening of the bottomed case 18, and the tip of the lead member 12 is bent to form a recess 21a provided on the outer surface of the insulating plate 21. It is stored in.

The volume of the void portion 20 provided in the bottomed case 18 is set in consideration of the volume expansion of the electrolytic solution 17 at the time of reflow soldering, and the first to the first embodiments of the present invention described below (Table 1).
As shown in FIG. 3, the volume of the space surrounded by the bottomed case 18 and the insulating plate 10 is 5%, 20%, and 40%.

FIG. 2 shows a chip-type aluminum electrolytic capacitor according to another embodiment of the present invention. The same parts as those of the chip-type aluminum electrolytic capacitor shown in FIG. Only the points will be explained. That is, in another embodiment shown in FIG. 2, the length of the anode foil, the cathode foil, and the separator (all not shown) forming the capacitor element 11 are adjusted and wound, and the winding diameter of the capacitor element 11 is adjusted. By adjusting the bottomed case 18
A void portion 20 is provided therein, and the volume of this void portion 20 is as shown in Example 4 of the present invention in (Table 1) below.
20% of the volume enclosed by the bottomed case 18 and the insulating plate 10
It was made.

FIG. 3 shows a chip type aluminum electrolytic capacitor according to still another embodiment of the present invention. The same parts as those of the chip type aluminum electrolytic capacitor shown in FIG. Only the differences will be described.
That is, the other embodiment shown in FIG.
1 from which the lead member 12 is pulled out and the sealing body 1
The gap portion 20 is provided in the bottomed case 18 by adjusting the gap 22 between the inner surface 9 and the gap portion 2.
The volume of 0 is 2 of the volume surrounded by the bottomed case 18 and the insulating plate 10, as shown in Example 5 of the present invention in (Table 1).
It is set to 0%.

Further, (Table 1) shows, for comparison, a conventional example in which a void portion is not provided by adjustment in the bottomed case (voids are 5% or less).

Further, (Table 1) shows the chip type aluminum electrolytic capacitors in the respective embodiments of the present invention described above and the chip type aluminum electrolytic capacitors shown in the conventional example at 50V10.
The results of the reflow soldering test in which 1000 pieces each are manufactured with a rating of μF are also shown.

[0014]

[Table 1]

As can be seen from this (Table 1), the number of warpage of the insulating plate is zero in each of the examples of the present invention. That is, since the chip type aluminum electrolytic capacitors of the respective embodiments of the present invention are provided by adjusting the volume of the void portion 20 in the bottomed case 18, reflow soldering at the time of mounting on a printed circuit board of an electronic device. Even if the electrolytic solution 17 expands in volume at some time, the increase in the internal pressure of the bottomed case 18 due to the expansion is reduced by the void portion 20 provided in the bottomed case 18, whereby the sealing body 19 is closed. Since the insulating plate 21 is not swollen and deformed, the insulating plate 21 is not pressed and warped. As a result, the chip-type aluminum electrolytic capacitor is inclined to be mounted on the printed circuit board of the electronic device by soldering. It can be performed in a stable state without the need.

However, in each of the above-described embodiments of the present invention, the volume of the void portion 20 is 5% of the inner volume of the bottomed case 18.
If it is less than 80 ° C., even if reflow soldering is performed at around 180 ° C., which is generally considered to be the lowest soldering temperature, the internal pressure caused by the compression of the internal space of the bottomed case 18 due to the volume expansion of the electrolytic solution 17 is Since the sealing member 19 cannot be sufficiently reduced, the sealing member 19 is swollen and deformed. As a result, the insulating plate 21 is pressed and warped.
The surface mounting surface of the outer surface of the is bent, which may adversely affect the mounting on the printed circuit board.

On the other hand, the volume of the void 20 is equal to the bottomed case 18
If it exceeds 40% of the inner volume of the capacitor, the size of the capacitor becomes too large, which is not preferable in practice.

In each of the above-described embodiments of the present invention, an example of various adjustment methods when the void portion 20 is provided in the bottomed case 18 has been described, but the void portion 20 may be variously described below. Can also be provided by
It goes without saying that even in these methods, the soldering onto the printed circuit board of the electronic device can be performed in a stable state as in the first to fifth embodiments of the present invention.

That is, as the first method, the anode foil 1
It is also possible to provide the void portion 20 in the bottomed case 18 by adjusting the thickness of the cathode foil 14 and the separator 15 and winding them, and by adjusting the winding diameter of the capacitor element 11.

As a second method, by adjusting the widths of the anode foil 13, the cathode foil 14 and the separator 15 and winding them, and adjusting the length of the capacitor element 11, the void portion 20 is formed in the bottomed case 18. Can be provided.

As a third method, the capacitor element 11
By adjusting the width, the length, or the thickness of the unwinding tape 16, the space 20 is formed in the bottomed case 18.
Can be provided.

As a fourth method, the capacitor element 11
By adjusting the diameter of the core of the
It is possible to provide the void portion 20 therein.

As a fifth method, the capacitor element 11
The void portion 20 can be provided in the bottomed case 18 by adjusting the gap between the surface of the bottomed case 18 from which the lead member 12 is not pulled out and the inner bottom surface of the bottomed case 18.

As a sixth method, it is possible to form the void portion 20 in the bottomed case 18 by adjusting the density of the separator 15.

As a seventh method, the void 20 can be provided in the bottomed case 18 by adjusting the void volume in the pit of the etched portion of the anode foil 13 or the cathode foil 14.

[0026]

As described above, according to the chip-type aluminum electrolytic capacitor of the present invention, the inner volume of the bottomed case is set to the lead member, the anode foil, the cathode foil, the separator, the winding tape,
When the product is mounted on a printed circuit board of an electronic device, the composition is such that the total volume of each electrolytic solution is added to the volume of the voids provided in the alpha case with bottom. Even if the electrolyte expands in volume during soldering, the increase in the internal pressure of the bottomed case due to the expansion is reduced by the voids provided in the bottomed case, which causes the sealing body to swell. Since the insulating plate is not deformed, it does not warp due to pressure on the insulating plate, and as a result, the chip type aluminum electrolytic capacitor does not tilt when mounted by soldering on the printed circuit board of electronic equipment. It can be performed in a stable state.

[Brief description of drawings]

FIG. 1 is a sectional view of a chip type aluminum electrolytic capacitor showing an embodiment of the present invention.

FIG. 2 is a sectional view of a chip type aluminum electrolytic capacitor showing another embodiment of the present invention.

FIG. 3 is a sectional view of a chip type aluminum electrolytic capacitor showing still another embodiment of the present invention.

FIG. 4 is a sectional view of a conventional chip-type aluminum electrolytic capacitor.

[Explanation of symbols]

 11 Capacitor Element 12 Lead Member 13 Anode Foil 14 Cathode Foil 15 Separator 16 Winding Tape 17 Electrolyte Solution 18 Bottomed Case 19 Sealing Body 20 Void 21 Insulation Plate

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location H01G 9/12 H01G 9/06 Z 9/12 Z (72) Inventor Teruhisa Miura Kadoma City, Osaka 1006 Kadoma Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A capacitor element in which an anode foil and a cathode foil to which lead members are connected are wound with a separator interposed therebetween and winding is stopped, an electrolytic solution impregnated in the capacitor element, and the capacitor element. A bottomed case for accommodating, a sealing body for sealing the opening of the bottomed case, and arranged to abut the end surface of the opening of the bottomed case,
Further, a void portion occupying 5% or more of this space is provided in the space surrounded by the bottomed case and the insulating plate of the chip type aluminum electrolytic capacitor having the insulating plate with the lead member facing the outer surface. Chip type aluminum electrolytic capacitor. 2. The chip type aluminum electrolytic capacitor according to claim 1, wherein the volume of the void portion is 5 to 40% of the volume of the space surrounded by the bottomed case and the insulating plate.