JPS607468Y2 - Chip type aluminum electrolytic capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a chip-type aluminum electrolytic capacitor.

In recent years, advances in electronic circuits and systems have created a need for the development of chip-type capacitors that have maximum capacitance per unit volume by minimizing external lead wires, and have a shape that allows automatic mounting on circuit boards. Ta.

Conventionally, tantalum solid capacitors and ceramic capacitors have been put into practical use as capacitors with the above-mentioned characteristics. Because the electrolyte adheres to the surface of the element, it is extremely difficult to mold it with synthetic resin, and it is difficult to mold it with synthetic resin.
High heat of ~200°C is directly applied to the device, which causes deterioration of the dielectric oxide film and loss of electrolyte, making the electrical characteristics of the capacitor unstable.Moreover, it is difficult to provide an explosion-proof function due to the structure, and chip type aluminum! capacitors have not yet been put into practical use.

In addition, chip-type aluminum electrolytic capacitors with electrodes in a laminated structure have been proposed, as in Japanese Utility Model Application Publication No. 54-84-1983, but because of the laminated structure, the capacitance is relatively small and it is difficult to obtain a large capacity. The manufacturing process is complicated and cannot be automated, making it expensive, and this configuration has drawbacks such as not being able to provide explosion-proof functionality.

The present invention was developed in view of the above-mentioned circumstances. After forming an ultraviolet curable resin layer on the surface of a wound capacitor element that has been impregnated with a paste-like electrolyte, it is placed on a substrate and lead terminals are attached. By connecting to external terminals and covering the exterior with a synthetic resin mold, and providing grooves in the exterior, high heat is not directly applied to the element, and the electrical characteristics are explosion-proof, large capacity, and easy to manufacture. The purpose is to provide a stable chip-type aluminum electrolytic capacitor.

An embodiment of the present invention will be described below with reference to the drawings.

That is, as shown in FIGS. 1 and 2, a wound capacitor element 1 impregnated in advance with a paste-like driving electrolyte is immersed in an ultraviolet curing resin or a UV curing resin layer 2 is applied to the surface by spray coating. Form.

Suitable examples of the UV-curable resin include epoxy acrylate, which is composed of an acrylic group that has a reactive main part and an epoxy resin that provides excellent physical properties after curing. It contains a benzoin alkyl ether type, anthraquinone type, benzophenone type, etc. as a sensitizer.

Immediately after forming the ultraviolet curable resin layer 2, a high pressure mercury lamp having a main wavelength of 365 nm or a 300 nm
It is irradiated with ultraviolet rays using a metal halide lamp with a long wavelength of ~450 nm, and is rapidly cured in about 5 to 10 seconds at an output of 8 ow/Cm.

In this case, the lamps may be arranged so that they emit light from two directions 180° apart, or the capacitor element 1 may be rotated so that the light is uniformly applied.

Next, the capacitor element 1 is molded into a pair of external terminals 3,
It is placed on a substrate 4 made of synthetic resin or ceramics that is integrally attached by inserting, welding, or pasting, and the lead terminal 5 led out from the capacitor element 1 is connected to the external terminal 3 by a method such as welding. .

Thereafter, the capacitor element 1 on the substrate 4 is molded with synthetic resin by a method such as transfer molding, casting, injection molding, etc., and is covered with an exterior 6.

In this case, the outer sheath 6 has a concave or V-shaped groove 7 on its periphery.
is provided, and when gas is generated from the capacitor element 1 due to overvoltage application or temperature rise, etc., and the internal gas pressure increases, the groove 7 is provided with an explosion-proof function to prevent cracks from forming and an explosion. It is something to keep.

The groove 7 may be provided all around the exterior 6, or may be provided only on the upper surface facing the substrate 4.

Moreover, the same effect can be obtained even if it is provided on the side surface of the exterior 6.

In addition, the external terminal 3 adopts a lead frame method with several terminals per frame, and is suitable for mass production if several tens of frames are molded at once, covered with the exterior 6, and finally the terminal part is cut from the lead frame. do.

Furthermore, as shown in FIGS. 3A and 3B, the substrate 4 has a semi-cylindrical recess that matches the shape of the capacitor element 1, and has locking parts 8 on both end faces of the recess and wings on both sides. Molding is easy if the portion 9 is provided and the capacitor element 1 is shaped into a shape in which the capacitor element 1 can be easily placed.

In this case, the wing portion 9 may be formed at one or several locations on a portion of both side surfaces.

In chip-type aluminum electrolytic capacitors constructed in this way, the ultraviolet curing resin is irradiated with ultraviolet rays and is rapidly cured from the outside surface. The resin will not peel off from the element.

Since the ultraviolet curing resin layer 2 is formed on the capacitor element 1, high heat is not directly applied during molding, and there is almost no deterioration of the dielectric oxide film or loss of the electrolyte, resulting in a capacitor with stable electrical characteristics. be able to.

Even if the gas pressure becomes high, the groove 7 provides an explosion-proof function, so an explosion can be reliably prevented.

Furthermore, since the conventional capacitor element 1 can be used as is, a large capacity chip-type aluminum electrolytic capacitor can be obtained.

Furthermore, the manufacturing process is extremely simple and can be automated, making it suitable for inexpensive mass production.

As described in detail above, according to the present invention, a capacitor element is coated with an ultraviolet curing resin layer, placed on a substrate with external terminals attached, and the lead terminals led out from the capacitor element are connected to the external terminals. By molding the capacitor element on the substrate with synthetic resin and providing grooves on the exterior, the electrical characteristics of the capacitor are stable.Even if the gas pressure becomes high, the explosion-proof function operates and can reliably prevent an explosion. Furthermore, it is possible to provide a chip-type aluminum electrolytic capacitor that can be automated, is suitable for mass production at low cost, and has a large capacity.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a chip-type aluminum electrolytic capacitor according to an embodiment of the present invention, FIG. 2 is a side sectional view thereof,
3A and 3B show a substrate according to another embodiment of the present invention, where A is a sectional view and B is a side sectional view. 1... Capacitor element, 2... Ultraviolet curing resin layer, 3... External terminal, 4...
Board, 5... Lead terminal, 6... Exterior, 7... Groove, 8... Locking part, 9...
...wing section.

Claims (3)

[Scope of utility model registration request] (1) A wound type capacitor element with lead terminals led out and impregnated with electrolyte, an ultraviolet curing resin layer formed on the surface of the capacitor element, a substrate on which the capacitor element is mounted, and an integrally mounted capacitor element on the substrate. 1. A chip-type aluminum electrolytic capacitor, comprising: an external terminal attached to the substrate and connected to the lead terminal; an outer casing formed by molding and covering a capacitor element on the substrate; and a groove provided in the outer casing. (2) Registration of a utility model characterized in that the substrate has a semi-cylindrical recess that matches the shape of the capacitor element, and that the recess has locking parts on both end faces and wing parts on both sides. A chip-type aluminum electrolytic capacitor according to claim 1. (3) The chip-type aluminum electrolytic capacitor according to claim 1 or 2, characterized in that a groove is provided on the top or side surface of the exterior.