JPS6350845Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a chip type capacitor, and in particular to an improvement in the structure of an anode lead electrode terminal of a chip type solid electrolytic capacitor.

A conventional chip-type solid electrolytic capacitor is shown in Figure 1.
As shown in Fig. 2, the tip part 3a of the anode lead electrode terminal (hereinafter referred to as electrode terminal) 3 is made by applying a plating layer such as solder plating to a thin metal plate and bending it into a step shape. It is located at a portion of a capacitor element (hereinafter abbreviated as a capacitor element) 1 where an anode wire 2 is present, and is joined by welding or the like. Thereafter, the structure was such that the capacitor element 1 was coated from the shoulder surface with a reinforcing resin 4 covering the anode wire 2 and its joints using epoxy resin or the like.

Therefore, the anode wire 2 and electrode terminal 3 of the capacitor element 1 are joined by a spot welding method or the like.
Although it is electrically and mechanically bonded, the heat and mechanical stress generated at this time will damage the anodized dielectric layer on the surface of the capacitor element 1, which will adversely affect the electrical characteristics of the capacitor (mainly leakage current). It is necessary to widen the distance X between the capacitor element 1 and the junction to an appropriate size that is not affected by stress. In addition, when the length H of the electrode terminal 3 necessary for mounting on a wiring board such as a printed circuit board is included, the total length W of the solid electrolytic capacitor becomes large, making it difficult to miniaturize the solid electrolytic capacitor. Also, since the above-mentioned X dimension is large, the reinforcing resin 4 applied to the shoulder surface of the capacitor element 1 is
flowed during drying and curing, producing resin protrusions, making it impossible for capacitor element 1 and electrode terminal 3 to form the same plane, resulting in lack of stability and weak adhesion when attached to a wiring board.

As described above, with the conventional electrode terminal structure, it is difficult to miniaturize with good volumetric efficiency, and the adhesion force after attachment to the substrate is low.

The purpose of this invention is to provide a chip-type solid electrolytic capacitor that has a compact structure with high volumetric efficiency that solves the above-mentioned drawbacks of the conventional capacitor, has a high adhesion force after mounting on a board, and is suitable for mass production. be.

That is, the present invention provides a chip-type solid electrolytic capacitor with an exposed cathode portion, in which a plate-shaped electrode terminal having a uniform thickness and connected to an anode wire of a capacitor element is arranged in a step-like manner along the extending direction of the anode wire. The electrode terminal is electrically connected to the anode wire with one end protruding from the tip of the anode wire, and the other end of the electrode terminal is bent to the end of the anode wire. A chip-type solid electrolytic capacitor is obtained, which is characterized in that the chip-type solid electrolytic capacitor is located toward the root side and is disposed in the same plane as the exposed cathode part of the capacitor element, and furthermore, the terminal part of the anode lead electrode terminal is connected to the anode wire. A chip-type solid electrolytic capacitor is obtained, which is characterized by an anode lead-out electrode terminal structure that is as thin as the cylindrical shape, and in which a plating layer is applied only to the surface of the anode lead-out electrode terminal. It will be done.

An embodiment of the present invention is shown below in Figures 3a, b to 7.
This will be explained using Figures a and b.

Embodiment 1 FIGS. 3a and 3b are a plan view and a side view of a chip-type solid electrolytic capacitor according to a first embodiment of the present invention, which is not covered with reinforcing resin. FIGS. 4a and 4b show a plan view and a side view of the chip-type solid electrolytic capacitor of the present invention in which the first embodiment is coated with a reinforcing resin.

First, a thin metal strip such as brass, nickel silver, or nickel is coated with a plating layer several microns thick, such as by solder plating. Electrode terminals 3 are formed by bending the tips of lead frames 3' (two-dot chain lines) connected at equal intervals P.

Next, metal powder with valve action such as tantalum is press-formed into a predetermined shape, sintered in a high-temperature vacuum furnace, and then anodized while being joined to a strip-shaped metal plate (not shown) at equal intervals. A capacitor element 1 is formed by sequentially forming a semiconductor layer made of a manganese dioxide layer, a graphite layer, and a conductive layer such as silver paste or solder on the surface of the dielectric material. Electrode terminals 3, which are formed by bending the tip of the connected lead frame 3' into a step shape, are attached to a strip-shaped metal plate at equal intervals within the length of the anode wire 2 of the capacitor element 1. Then, the terminal end 3b of the electrode terminal 3 and the anode wire 2 are electrically joined by spot welding or the like to the shoulder surface of the capacitor element and the joint at a distance of _X1 . Next, a plurality of capacitor elements are attached to a strip-shaped metal plate at equal intervals, and reinforcing resin 4 is used to cover the joint from the shoulder surface of the capacitor element 1 to the anode wire 2 using epoxy resin as shown in FIG. After coating and heating and curing, aging and characteristic tests are performed. Then, the length dimension H ₂ of the terminal end 3b of the electrode terminal 3 is set to 0.2 to 0.2 at the same time.
A chip-type solid electrolytic capacitor according to the first embodiment of the present invention is cut by cutting the total length W ₁ of a chip-type solid electrolytic capacitor with a predetermined length of about 0.5 m/m (from the place where a notch has been made in advance using a press, etc.). Obtain a solid electrolytic capacitor.

Embodiment 2 FIGS. 5a and 5b are a plan view and a side view of a chip-type solid electrolytic capacitor according to a second embodiment of the present invention, which is not coated with reinforcing resin. In the second embodiment of the present invention, the terminal end 3b of the electrode terminal 3 described in the first embodiment is made as thin as the anode wire 2,
After forming the terminal end portion 3c of the electrode terminal and electrically joining it to the anode wire 2 by spot welding or the like, a reinforcing resin 4 is formed to obtain a chip type solid electrolytic capacitor.

Embodiment 3 Figures 6a, b, and c show a plan view and a side view of a chip-type solid electrolytic capacitor according to a third embodiment of the present invention, in which the reinforcing resin is not coated, and a perspective view of the anode lead-out electrode terminal. In the third embodiment of the present invention, the terminal end 3d of the electrode terminal 3 is formed into a cylindrical shape having a size that allows the anode wire 2 to fit into the terminal end 3b of the electrode terminal 3 described in the first embodiment. After caulking to electrically connect with the anode wire 2, a reinforcing resin 4 is coated to obtain a chip type solid electrolytic capacitor.

Embodiment 4 FIGS. 7a and 7b show a plan view and a side view of a chip-type solid electrolytic capacitor according to a fourth embodiment of the present invention, in which the reinforcing resin 4 is not covered. In the fourth embodiment of the present invention, in the plating layer of the electrode terminal 3 described in the first to fourth embodiments,
A chip type solid electrolytic capacitor is formed in which a plating layer 3Z such as solder plating is applied only to the surface side.

According to the present invention, (a) Since the electrode terminal 3 is provided within the length range of the anode wire 2 of the capacitor element 1, the overall length W ₁ of the chip-type solid electrolytic capacitor of the present invention is smaller than that of the conventional chip-type solid electrolytic capacitor. Compared to the total length of the capacitor, it can be made smaller as W > W ₁ . Therefore, under the same conditions as the dimension H=H ₁ of the joint portion of the electrode terminal 3 with the wiring board attachment, the size is reduced within the range of the length of the anode wire. Moreover, since the flow of the reinforcing resin 4 when it dries and hardens can be stopped by the electrode terminal 3, the capacitor element 1 and the electrode terminal 3 can be configured on the same plane, resulting in good stability when attached to a wiring board, etc. This makes the adhesion stronger.

(b) Terminal parts 3b, 3c of the anode extraction electrode terminal 3,
The anode wire 2 is joined at 3d, and the distance between the capacitor element 1 and the joint becomes wide (X<X ₁₎ , so that heat and mechanical stress caused by spot welding etc. do not affect the capacitor element 1. .

(c) In manufacturing, a plurality of electrode terminals 3 are attached at equal intervals and connected to a lead frame 3'.
Since bonding, application of the reinforcing resin 4, aging, and inspection work can be performed simultaneously without separating the parts, the manufacturing process becomes extremely simple. Moreover, it has the remarkable effect of being suitable for mass production.

(D) As in the second embodiment of the present invention, if the terminal end 3c of the anode lead electrode terminal 3 is made as thin as the anode wire 2, the welding current value during joining such as spot welding can be reduced, and therefore the capacitor The influence of thermal stress on the element 1 is further reduced.

(E) As in the third embodiment of the present invention, the terminal end 3d of the anode lead electrode terminal 3 has a cylindrical structure and is caulked, so that there is no effect of thermal stress on the capacitor element 1.

(f) As in the fourth embodiment of the present invention, a plating layer 3Z of solder or the like is provided only on the surface side of the anode lead-out electrode terminal 3.
Since the opposite side has no plating layer, the former has good and stable bonding properties when attached to the wiring board, and the latter has good bonding properties when attached to the wiring board, while the latter has good bonding properties between the anode lead electrode terminal 3 and the anode wire 2. Good bondability,
It has the advantage of maintaining stable bonding properties.

As described above, the chip type solid electrolytic capacitor according to the present invention has high volumetric efficiency, is suitable for mass production, and is highly reliable, and has great industrial value.

[Brief explanation of the drawing]

FIGS. 1a and 1b are a plan view and a side view of a conventional chip-type solid electrolytic capacitor not coated with reinforcing resin. FIGS. 2a and 2b are a plan view and a side view of a conventional chip-type solid electrolytic capacitor coated with reinforcing resin. FIGS. 3a and 3b are a plan view and a side view of a chip-type solid electrolytic capacitor of the first embodiment which is not coated with the reinforcing resin of the present invention. FIGS. 4a and 4b are a plan view and a side view of a chip-type solid electrolytic capacitor of the first embodiment coated with the reinforcing resin of the present invention. FIGS. 5a and 5b are a plan view and a side view of a chip-type solid electrolytic capacitor according to a second embodiment of the present invention which is not coated with reinforcing resin. FIGS. 6a, 6b, and 6c are a plan view and a side view of a chip-type solid electrolytic capacitor according to a third embodiment of the present invention not covered with reinforcing resin, and a perspective view of an anode lead-out electrode terminal. FIGS. 7a and 7b are a plan view and a side view of a chip-type solid electrolytic capacitor according to a fourth embodiment of the present invention which is not coated with reinforcing resin. Symbols in the figure: 1... Capacitor element, 2... Anode wire, 3... (Anode extraction) electrode terminal, 3a...
Tips of electrode terminals, 3b, 3c, 3d...terminal ends of electrode terminals, 3Z...(anode extraction) plating layer of electrode terminals, 3'...connected lead frames,
4... Reinforcing resin, H, H ₁ ... Dimensions of the joint between the electrode terminal and wiring board mounting, H ₂ ... Length dimension of the terminal end, P, P _o ... Equal spacing dimensions of the lead frame,
W, W ₁ ... Total length of chip type solid electrolytic capacitor, X, X ₁ ... Distance between the shoulder surface of the capacitor element and the joint.

Claims (1)

[Claims for Utility Model Registration] (1) In a chip-type solid electrolytic capacitor with an exposed cathode part, a plate-shaped electrode terminal having a uniform thickness connected to an anode wire of a capacitor element is connected to the anode wire in the extending direction of the anode wire. The electrode terminal is bent in a step-like manner along the direction of the electrode terminal, and one terminal end of the electrode terminal protrudes from the tip of the anode wire and is electrically connected to the anode wire, and the other terminal end of the electrode terminal is electrically connected to the anode wire. A chip-type solid electrolytic capacitor, characterized in that a portion is located toward the base of the anode wire and is disposed in the same plane as the exposed cathode portion of the capacitor element. (2) The chip-type solid electrolytic capacitor according to claim 1, wherein the terminal end of the anode lead-out electrode terminal is formed to be as thin as the anode wire. (3) The chip-type solid electrolytic capacitor according to claim 1, wherein the terminal end of the anode lead-out electrode terminal is formed into a cylindrical shape into which the anode wire is inserted. (4) The chip-type solid electrolytic capacitor according to claim 1, wherein a plating layer is provided only on the surface side of the anode lead-out electrode terminal.