JP3125366B2 - Method for manufacturing solid electrolytic 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 method for manufacturing a solid electrolytic capacitor suitable for surface mounting on a printed circuit board or the like used in small electronic equipment.

[0002]

2. Description of the Related Art As electronic devices have become smaller and more portable, high-density mounting technology of electronic components constituting the devices has become indispensable. For high-density mounting, there is a strong demand for miniaturization of resistors and multilayer ceramic capacitors that are used in a large number of electronic components, and the size is 1.6 mm × 0.8 mm (so-called 1608 component), which is now called a chip component. In addition, ultra-small products of 1.0 mm × 0.5 mm (so-called 1005 parts) have been developed and used. Under the circumstances where such miniaturization is required, electrolytic capacitors having relatively large-capacity characteristics can be further miniaturized from those having cylindrical lead terminals as in the past, and the density is increased. Leadless rectangular solid electrolytic capacitors suitable for surface mounting have been developed.

[0003] As this kind of rectangular solid electrolytic capacitor,
A structure manufactured by the manufacturing method shown in FIGS. 6A to 6D is known. (A) to (D) of FIG.
FIG. 3 is an external perspective view showing the main steps in manufacturing a conventional solid electrolytic capacitor for surface mounting in the order of steps.

[0006] In FIG. 6A, reference numeral 10 denotes a rectangular outer case whose inside is formed into a cylindrical concave portion.
The opening portion of the rectangular outer case 10 is formed so as to have a tapered portion in a cone shape wider than the diameter of the internal cylindrical concave portion. The capacitor element 12 is inserted into the rectangular outer case 10 thus formed. The capacitor element 12 is prepared by attaching metal terminals 14 and 16 to metal foils (not shown) for the plus electrode and the minus electrode in advance by stitching or ultrasonic welding, and then through a separator (not shown). It is formed by winding a metal foil, impregnating it with an electrolytic solution, firing, and then performing a chemical conversion treatment. FIG. 6B shows a state in which the capacitor element 12 is housed in the rectangular outer case 10 and a molten epoxy resin 18 as a sealing material is injected and sealed. In FIG. 6C, the lower portion of the tapered portion of the rectangular outer case 10 is set to a predetermined length with the epoxy resin 18 and the metal terminal 1.
4 and 16 are cut together and the metal terminals 1 are
4 and 16 are exposed. In FIG. 6D, external connection terminals 20 and 22 formed by processing metal plates are attached to the metal terminals 14 and 16 exposed in the cutting step by ultrasonic welding or laser welding or the like. Thereafter, if the rated value, the polarity of the electrodes, and the like are printed on the surface of the rectangular outer case 10, the solid electrolytic capacitor for surface mounting is completed.

[0005]

However, according to the above-described method for manufacturing a solid electrolytic capacitor, FIG.
Since the metal terminals 14 and 16 are exposed only in the vicinity of the center of the cut surface of the rectangular outer case 10 by the cutting step as shown in (1), the external connection terminals 20, 22 and the like are newly added to the end of the rectangular outer case 10. A process for attaching a terminal was required. This external connection terminal is formed by processing a metal plate and attaching it by ultrasonic welding or the like as described above.
Positioning and attaching the small external connection terminals 20 and 22 with high precision to the side surface of the small exterior case 10 for surface mounting has a drawback that it is a rather complicated operation process.

It is an object of the present invention to provide a method of manufacturing a solid electrolytic capacitor which can simplify the manufacturing process by omitting the step of attaching the external connection terminals.

[0007]

A method of manufacturing a solid electrolytic capacitor according to the present invention is manufactured by storing a capacitor element in a rectangular outer case having an opening wider than a bottom and having a taper, and sealing the opening with an epoxy resin or the like. In the solid electrolytic capacitor, a portion exposed from the capacitor element as a metal terminal derived from the capacitor element is processed or formed so as to at least protrude from the bottom side surface of the square outer case, and the epoxy resin or the like is squared in the square outer case. To cover a part of the metal terminal, and cut the metal case together with the outer case in a direction parallel to the bottom of the outer case (opening side) and in a vertical direction (side surface) so that each metal terminal is Are exposed to the opening side and at least one side surface.

In the above-mentioned manufacturing method, it is preferable to use, as the metal terminal, a metal terminal which is flattened so that a portion exposed from the capacitor element at least projects outside the bottom side surface of the rectangular outer case.

Further, as the metal terminal, a metal terminal which is welded to a lead frame protruding outside at least from the bottom side surface of the rectangular outer case can be used.

[0010]

According to the method for manufacturing a solid electrolytic capacitor of the present invention, a metal terminal is used in which a portion exposed from the metal foil is processed or formed so that at least a portion exposed from the bottom side of the rectangular outer case is outside. After the cutting step, the structure is such that both metal terminals are exposed not only on the opening side of the outer case but also on the side surfaces of the outer case, and it is not necessary to newly connect external connection terminals.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the method for manufacturing a solid electrolytic capacitor according to the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows a method of manufacturing a solid electrolytic capacitor according to one embodiment of the present invention.
FIG. 4 is a sectional structural view of a cutting step for forming a terminal structure by this manufacturing method. FIG. 2 is an external perspective view sequentially showing main manufacturing steps of the solid electrolytic capacitor shown in FIG.
For convenience of explanation, the same parts as those of the conventional example shown in FIG. 6 will be described with the same reference numerals.

FIG. 1A shows a state in which the capacitor element 12 is housed in a rectangular outer case 10, and a molten epoxy resin 18 as a sealing material is injected and sealed (FIG. 2B). FIG. Here, what is different from the conventional one is the metal terminals 14 and 16 derived from the end face of the capacitor element 12. That is, as shown in FIG. 1A, metal terminals 14 and 16 having portions 14a and 16a partially processed or formed flat are used. The flat portions 14a and 16a may be formed to be long as shown by a two-dot chain line, but the width is set so as to be in contact with the tapered portion of the outer case 10. FIG.
(B) shows the outer case 10, the epoxy resin 18 and the metal terminals 1 along the alternate long and short dash line C1 shown in FIG.
FIG. 4 is a cross-sectional structural view of a state in which sections 4 and 16 are cut. FIG. 1C further shows the dashed-dotted lines C2 and C shown in FIG.
FIG. 3 is a cross-sectional structural view after being cut along the side surface of the outer case 10 as shown in FIG. 3, and the tapered portion of the outer case 10 is not cut off as shown in FIG. It is formed. As can be seen from FIGS. 1C and 2C, the flat portions 1 of the metal terminals 14 and 16 are formed.
4a and 16a extend to the side surface of the outer case 10 and are exposed when the cutting step is completed. Therefore, there is no need to connect an external connection terminal as in the related art.

FIG. 3 shows another embodiment of the method for manufacturing a solid electrolytic capacitor according to the present invention. FIGS. 3A to 3C show a cutting step for forming a terminal structure of the capacitor according to this manufacturing method. It is sectional drawing. In this case, the flat portions 14a and 16a of the metal terminals 14 and 16 are
Is used. This facilitates the positioning of the metal terminals 14 and 16,
There is an advantage that the position of the first cut surface C1 can be easily specified and the position when the capacitor element 12 is stored in the outer case 10 can be easily fixed. Finally, a large amount of the epoxy resin 18 is not exposed around the exposed portions of the metal terminals 12 and 16 on the side surface of the outer case 10 as shown in FIG.

FIG. 4 shows another embodiment of the method for manufacturing a solid electrolytic capacitor according to the present invention.
FIG. 3 is an external perspective view of the capacitor element 12 using the flattened portions 14a, 16a of the metal terminals 14, 16 which are processed or formed to be wide on both sides. FIG. 4B shows a state in which the capacitor element 12 is housed in a tapered outer case 10 having a fitting portion b as shown in FIG. 3A and has undergone a cutting step, and FIG. FIG. 4C shows a state in which the sheet is housed in the tapered outer case 10 having no fitting portion as shown in FIG. Regardless of the type of the outer case, the electrode terminals 14 and 1 are required after the cutting process.
A solid electrolytic capacitor having a terminal structure in which the six flat portions 14a and 16a extend to two opposing side surfaces of the outer case can be realized.

FIG. 5 shows still another embodiment of the method for manufacturing a solid electrolytic capacitor according to the present invention. FIG. 5A shows flat portions 14a and 16a of metal terminals 14 and 16.
FIG. 4 is an external perspective view of a capacitor element 12 using a material which is processed or formed to be wide on one side. FIG. 5B shows a state in which this capacitor element 12 is housed in a tapered outer case 10 having a fitting portion b as shown in FIG. 3A and has undergone a cutting step, and FIG. FIG. 5C shows a state in which the sheet is housed in the tapered outer case 10 having no fitting portion as in the case of FIG. Regardless of which type of outer case, the electrode terminal 1
A solid electrolytic capacitor having a terminal structure in which 4, 16 flat portions 14a and 16a extend to one side of the outer case can be realized.

Incidentally, as the metal terminals described so far,
Even if a terminal welded to at least the lead frame protruding from the bottom side surface of the rectangular outer case is used, the same effect as that obtained by using the above-described wide-processed or formed terminal can be obtained. In particular, as described in the above embodiment, when the capacitor element 12 is formed by winding the electrode foil, the flat portions 14a and 16a may be connected to one side surface of the square outer case 10 depending on the mounting positions of the metal terminals 14 and 16. It may be difficult to arrange them in parallel (or vertically). In such a case, if the terminal welded to the lead frame is used as the metal terminal, the arrangement can be adjusted when the lead frame is welded.

When aluminum is used for the metal terminals 14 and 16, a clad material in which a metal such as copper that can be soldered is joined to the flat portions 14a and 16a is used, and the solderable metal is exposed by a cutting process. May be.

Further, in the embodiment, a solid electrolytic capacitor using a capacitor element wound with an electrode foil has been described. However, if the electrode is drawn through a metal terminal, a non-wound type in which a solid electrolyte layer is formed on an anode body is used. The present invention can be applied to a solid electrolytic capacitor of the type described above.

[0020]

As is apparent from the above-described embodiments, according to the present invention, when forming the capacitor element, the metal terminals attached to the respective metal foils for the plus electrode and the minus electrode are processed or formed flat. Can be used to realize a terminal structure in which the cut exposed surface of each metal terminal extends to the side surface of the outer case after the cutting step. Therefore, the step of connecting the external connection terminal after the cutting step as in the related art And the manufacturing process can be simplified, and the external connection terminals do not come off during or after the manufacturing process, thereby improving reliability.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the above-described embodiment, and various design changes can be made without departing from the spirit of the present invention. It is.

[Brief description of the drawings]

FIGS. 1A to 1C are cross-sectional views showing one embodiment of a method for manufacturing a solid electrolytic capacitor according to the present invention, and FIGS. 1A to 1C are cross-sectional structural views of a cutting step for forming a terminal structure according to the manufacturing method. .

FIGS. 2A to 2C are external perspective views of main steps of manufacturing the solid electrolytic capacitor shown in FIG. 1, and FIGS.

FIGS. 3A to 3C are cross-sectional views showing another embodiment of a method for manufacturing a solid electrolytic capacitor according to the present invention, and FIGS. 3A to 3C are cross-sectional structural views of a cutting step for forming a terminal structure according to the manufacturing method. is there.

FIG. 4 is still another embodiment of the method for manufacturing a solid electrolytic capacitor according to the present invention, in which (A) is an external perspective view of a capacitor element using a flat portion of a metal terminal processed to be wide on both sides. (B) is an external perspective view after the end of the cutting step when an exterior case with a fitting portion is used, and (C) is an external perspective view after the end of the cutting step when an exterior case without a fitting portion is used. It is.

FIG. 5 is still another embodiment of the method for manufacturing a solid electrolytic capacitor according to the present invention, in which (A) is an external perspective view of a capacitor element using a flat part of a metal terminal processed to be wide on one side, (B) is an external perspective view after the end of the cutting step when using the exterior case with the fitting part, and (C) is an external perspective view after the end of the cutting step when the exterior case without the fitting part is used. is there.

FIGS. 6A to 6D are views showing a conventional method for manufacturing a terminal structure of a solid electrolytic capacitor, and FIGS. 6A to 6D are external perspective views showing main manufacturing steps in the order of steps.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Square outer case 12 Capacitor element 14 Metal terminal 14a Flat part 16 Metal terminal 16a Flat part 18 Epoxy resin 20 External connection terminal 22 External connection terminal b Fitting part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-120711 (JP, A) JP-A-58-66634 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01G 9/004 H01G 9/00 H01G 9/08 H01G 13/00 305

Claims (3)

(57) [Claims] 1. A solid electrolytic capacitor made by housing a capacitor element in a rectangular outer case having an opening wider than a bottom and having a taper, and sealing with an epoxy resin or the like, wherein said metal terminal is derived from said capacitor element. After processing or forming such that the portion exposed from the capacitor element is at least out of the bottom side surface of the rectangular outer case, filling the rectangular outer case with the epoxy resin or the like to cover a part of the metal terminal, The metal terminal is cut in a direction parallel to the bottom of the outer case (opening side) and in a direction perpendicular to the bottom (side surface) together with the case to expose the metal terminals to the opening side and at least one side surface of the outer case. To manufacture solid electrolytic capacitors. 2. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein said metal terminal is formed so as to be flat so that a portion exposed from said capacitor element projects outside at least a bottom side surface of said rectangular outer case. 3. The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the metal terminal is welded to a lead frame projecting out of at least a bottom side surface of the rectangular outer case.