JPH09275045A - Aluminum electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum electrolytic capacitor which can improve the loading capability to a printed circuit board. SOLUTION: A metal case 12 for accommodating a capacitor element 11 impregnated with the electrolyte for driving, a sealing body 14 for sealing the aperture of this metal case 12, an insulating plate 15 arranged at the end surface of the aperture of the metal case 12, and a pair of lead wires 13 which are led from the capacitor element 11 and is also led to the external side through the sealing body 14 and insulating plate 15 and are bent at the end portions along the substrate setting surface of the printed circuit board are provided, and the sealing body 14 is formed of a rubber material having the tensile elasticity of 4N/mm<2> or more at the temperature higher than the soldering process temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum electrolytic capacitor used for various electronic devices.

[0002]

2. Description of the Related Art In a conventional aluminum electrolytic capacitor of this type, as shown in FIG. 4, a separator is interposed between an anode foil and a cathode foil having an oxide film formed by electrolytically oxidizing the surface of an aluminum electrode foil. To form a capacitor element 1 and impregnate the capacitor element 1 with a driving electrolytic solution, and then to impregnate the driving electrolytic solution with the capacitor element 1 in a bottomed cylindrical shape made of aluminum. It is housed in the metal case 2, and the sealing body 3 is arranged in the opening of the metal case 2, and the pair of lead wires 4 drawn out from the capacitor element 1 are passed through the through hole 3 a of the sealing body 3. After that, by bending the opening end of the metal case 2 inward, the sealing body 3 is pressed to seal the opening of the metal case 2 with the sealing body 3. An insulating plate 5 is arranged on the end surface of the opening of the metal case 2, and the pair of lead wires 4 are passed through the through holes 5a of the insulating plate 5 and led out to the outside. Lead wire 4
The flat portion 4a is formed by subjecting the flat portion 4a to a flat shape, and the flat portion 4a is bent along the surface of the insulating plate 5 on which the printed board is placed.

When this aluminum electrolytic capacitor is installed on a printed circuit board, the flat parts 4a of the pair of lead wires 4 bent along the printed circuit board installation surface of the insulating plate 5 are connected to the wiring part of the printed circuit board by soldering. However, this solder connection is made in a solder reflow bath. In this case, the temperature in the solder reflow bath is 230 ° C in consideration of the melting point of the solder, the reliability of connection, and the connectivity of other electronic components.
That's all.

Further, as the sealing member 3, a vulcanized peroxide, resin vulcanized, sulfur vulcanized, quinoid vulcanized butyl rubber or a peroxide vulcanized, sulfur vulcanized ethylene propylene rubber is used. ing.

[0005]

However, in recent years, the solder reflow condition has become higher in temperature with the multi-functionalization of mounting components other than aluminum electrolytic capacitors and the high density mounting of circuit boards. , As the sealing body 3,
Those having a low tensile modulus or a low tensile elongation were used.

However, those having a low tensile modulus are
Metal case 2 of aluminum electrolytic capacitor during solder reflow
There is a problem that the internal pressure rises to swell the sealing body 3, and the bulging of the sealing body 3 reduces the mountability.

Further, a material having a low tensile elongation has a problem that a rubber crack is generated in a narrowed portion of the sealing body 3 during solder reflow.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an aluminum electrolytic capacitor capable of improving mountability on a printed circuit board.

[0009]

In order to achieve the above object, an aluminum electrolytic capacitor of the present invention has a bottomed cylindrical metal case for accommodating a capacitor element impregnated with a driving electrolytic solution, and a metal case of the metal case. A sealing body that seals the opening, an insulating plate disposed on the end face of the opening of the metal case, and is pulled out from the capacitor element, and is pulled out to the outside through the sealing body and the insulating plate, and the tip thereof is provided. A pair of lead wires whose parts are bent along the surface of the insulating plate on which the printed circuit board is mounted, and the sealing body is made of a rubber material having a tensile elastic modulus of 4 / mm ² or more at a temperature of a soldering temperature or higher. With this configuration, the mountability on the printed circuit board can be improved.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION According to the first aspect of the present invention, a bottomed cylindrical metal case for accommodating a capacitor element impregnated with a driving electrolytic solution and an opening of the metal case are sealed. A sealing body, an insulating plate disposed on the end surface of the opening of the metal case, and pulled out from the capacitor element,
And a pair of lead wires that are pulled out to the outside through the sealing body and the insulating plate and are bent at the tip end along the printed board installation surface of the insulating plate, and the sealing body having a soldering temperature equal to or higher than the soldering temperature. Tensile modulus at temperature of 4
It is made of a rubber material of / mm ² or more, and if it is a rubber material that constitutes this sealing body, the sealing body will not swell even if the solder reflow conditions at the time of mounting on the printed circuit board become higher. As a result, it is possible to improve the mountability on the printed circuit board without the deterioration of the mountability due to the swelling of the sealing body as in the conventional case.

According to a second aspect of the present invention, there is provided a bottomed cylindrical metal case for accommodating the capacitor element impregnated with the driving electrolytic solution, and a sealing body for sealing the opening of the metal case.
The insulating plate disposed on the end face of the opening of the metal case and the capacitor element are drawn out to the outside through the sealing body and the insulating plate, and the tip of the insulating plate is placed on the printed board mounting surface of the insulating plate. A pair of lead wires that are bent along a line, and the sealing body is made of a rubber material having a tensile elongation of 50% or more at a temperature of a soldering temperature or higher. For example, even if the solder reflow condition at the time of mounting on a printed circuit board becomes higher in temperature, the occurrence rate of rubber cracks in the narrowed portion of the sealing body can be significantly reduced.

Next, specific embodiments of the present invention and comparative examples will be described. (Embodiment 1) FIG. 1 is a sectional view of an aluminum electrolytic capacitor according to Embodiment 1 of the present invention. In FIG. 1, 11 is a capacitor element, and 11 is a surface of an aluminum electrode foil. Is formed by electrolytically oxidizing an anode film and a cathode foil having an oxide film formed thereon, with a separator interposed therebetween. The capacitor element 11 is impregnated with a driving electrolytic solution, and then the capacitor element 11 impregnated with the driving electrolytic solution is housed in a bottomed cylindrical metal case 12 made of aluminum. Reference numeral 13 denotes a pair of lead wires led out from the capacitor element 11. The pair of lead wires 13 penetrates a through hole 14a of a sealing body 14 provided at an opening of the metal case 12, and then the metal case. By bending the opening end of 12 inward, the sealing body 14 is pressed to seal the opening of the metal case 12 with the sealing body 14. Reference numeral 15 is an insulating plate disposed on the end face of the opening of the metal case 12. The pair of lead wires 13 are penetrated through a through hole 15a provided in the insulating plate 15 to be drawn out to the outside, and further drawn out to the outside. The flattened portion 1 is formed by applying flattening processing to the tip portions of the pair of lead wires 13.
3a is formed, and the flat portion 13a is bent along the surface of the insulating plate 15 on which the printed circuit board is mounted to form an aluminum electrolytic capacitor.

The aluminum electrolytic capacitor shown in FIG.
As the sealing body 14 in the sensor, the solder processing temperature (230
Tensile elastic modulus is 4N at a temperature (250 ° C) or above
/ Mm ^TwoAbove (4 N / mm^Two, 5N / mm^Two, 6 N / mm^Two, 7N /
mm^Two) Is a peroxide vulcanized butyl rubber sealant.
Lumi electrolytic capacitor was constructed.

(Embodiment 2) As a sealing body 14 in the aluminum electrolytic capacitor shown in FIG.
Tensile elongation is 5 at temperatures above 30 ℃ (250 ℃)
An aluminum electrolytic capacitor was constructed by using a peroxide-vulcanized butyl rubber sealing material of 0% or more (50%, 60%, 70%).

(Comparative Example 1) As a sealing body 3 in the aluminum electrolytic capacitor shown in FIG.
℃) above the temperature (250 ℃) tensile modulus of 4 /
An aluminum electrolytic capacitor was constructed by using a peroxide-vulcanized butyl rubber sealing body having a size of 2 mm / mm ² or less (2 N / mm ² , 3 N / mm ² ).

(Comparative Example 2) As the sealing body 3 in the aluminum electrolytic capacitor shown in FIG.
Tensile elongation is 50% at temperatures above (° C) (250 ° C)
The following (40%, 30%) peroxide vulcanized butyl rubber sealing body was used to form an aluminum electrolytic capacitor.

The aluminum electrolytic capacitors according to the first embodiment and the comparative example 1 of the present invention described above each use a γ-butyrolactone-based electrolytic solution as a driving electrolytic solution and have a size of 6.3φ × 5.5 L. It was made.

Further, the second embodiment of the present invention and the second comparative example.
As the aluminum electrolytic capacitor in, the γ-butyrolactone-based electrolytic solution was used as the driving electrolytic solution, and the size was 4φ × 5.5 L.

FIG. 2 shows the solder reflow temperatures (220 ° C., 230 ° C., 240 ° C., 250 ° C.) of the aluminum electrolytic capacitors obtained according to the first embodiment of the present invention and the comparative example 1, respectively.
The mounting rate after solder reflow at 260 ° C. and 270 ° C.) is shown. As is clear from FIG. ² , in Comparative Example 1 in which the tensile elastic moduli are 2 N / mm ² and 3 N / mm ² , ,
Solder reflow temperature of aluminum electrolytic capacitor is 250 ℃,
At high temperatures of 260 ° C and 270 ° C, the mounting rate cannot be 100%, but the tensile modulus of elasticity is 4N / mm ² or more.
In ^{/ mm 2, 5N / mm 2} , 6N / mm 2, a first embodiment of the present invention which is a 7N / mm ^2, since there is no fact that the sealing body is bulging, 250 ° C. solder reflow temperature of the aluminum electrolytic capacitor The mounting rate of 100% can be reliably obtained even at high temperatures of 260 ° C. and 270 ° C.

FIG. 3 shows the solder reflow temperatures (220 ° C., 230 ° C., 240 ° C., 250 ° C.) of the aluminum electrolytic capacitors obtained according to the first embodiment of the present invention and the comparative example 1, respectively.
The cracking rate of the sealing body after solder reflow at 260 ° C. and 270 ° C. is shown. As is clear from FIG. 3, the tensile elastic modulus is 2 N / mm ² and 3 N / mm ^2. , The solder reflow temperature of the aluminum electrolytic capacitor is 24
At high temperatures of 0 ℃, 250 ℃, 260 ℃ and 270 ℃,
The cracking rate of the sealing body gradually increases, but the tensile elastic modulus is 4 N / mm
² or more 4N / mm ² , 5N / mm ² , 6N / mm ² , 7N / mm ²
In Embodiment 1 of the present invention, when the solder reflow temperatures of the aluminum electrolytic capacitor are 260 ° C. and 270 ° C., the sealing body cracks slightly in the tensile elastic modulus of 4 N / mm ² , 5 N / mm ^2. Occurs, but the tensile modulus is 6 N /
In the case of mm ² and 7 N / mm ² , even if the solder reflow temperature of the aluminum electrolytic capacitor reaches a high temperature of 260 ° C. or 270 ° C., the sealing body cracking does not occur.

[0021]

As described above, the aluminum electrolytic capacitor of the present invention has a bottomed cylindrical metal case for accommodating a capacitor element impregnated with a driving electrolytic solution, and a sealing body for sealing the opening of the metal case. And an insulating plate disposed on the end face of the opening of the metal case, and drawn out from the capacitor element and penetrating the sealing body and the insulating plate to the outside, and the end of the printed board of the insulating plate. A pair of lead wires bent along the installation surface are provided, and the sealing body is made of a rubber material having a tensile elastic modulus of 4 N / mm ² or more at a temperature equal to or higher than the soldering temperature. Even if the solder reflow condition during mounting rises in temperature, the sealing body will not swell,
As a result, it is possible to improve the mountability on the printed circuit board without the deterioration of the mountability due to the swelling of the sealing body as in the related art.

[Brief description of drawings]

FIG. 1 is a sectional view showing an aluminum electrolytic capacitor according to a first embodiment of the present invention.

FIG. 2 is a measurement diagram showing a mounting rate after solder reflow at the solder reflow temperature of the aluminum electrolytic capacitors obtained according to the first embodiment of the present invention and the comparative example 1, respectively.

FIG. 3 is a measurement diagram showing the sealing body cracking ratio after solder reflow at the solder reflow temperature of the aluminum electrolytic capacitors obtained according to Embodiment 1 of the present invention and Comparative Example 1 respectively.

FIG. 4 is a sectional view showing a conventional aluminum electrolytic capacitor.

[Explanation of symbols]

 11 Capacitor Element 12 Metal Case 13 Pair of Lead Wires 14 Sealing Body 15 Insulation Plate

Claims (2)

[Claims] 1. A bottomed cylindrical metal case for accommodating a capacitor element impregnated with a driving electrolytic solution, a sealing body for sealing an opening of the metal case, and an end face of the opening of the metal case. An insulating plate, and a pair of lead wires that are drawn out from the capacitor element and that extend through the sealing body and the insulating plate to the outside, and that have their tips bent along the printed board installation surface of the insulating plate. Equipped with
An aluminum electrolytic capacitor in which the sealing body is made of a rubber material having a tensile elastic modulus of 4 N / mm ² or more at a temperature of a soldering temperature or higher. 2. A cylindrical metal case having a bottom, which houses a capacitor element impregnated with a driving electrolytic solution, a sealing body for sealing the opening of the metal case, and an end face of the opening of the metal case. An insulating plate, and a pair of lead wires that are drawn out from the capacitor element and that extend through the sealing body and the insulating plate to the outside, and that have their tips bent along the printed board installation surface of the insulating plate. Equipped with
An aluminum electrolytic capacitor in which the sealing body is made of a rubber material having a tensile elongation of 50% or more at a temperature equal to or higher than a solder processing temperature.