JPH01268014A - Manufacture of tantalum solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To reduce the stress at th time of welding of a neck base part which is a tantalum wire drawing-out part of a capacitor element and stabilize a laser welding condition, by welding the joint of an outside anode terminal and an anode leading-out wire by laser from an inclined direction as they are always held to lightly be in contact with each other. CONSTITUTION:A capacitor element 1 in which an anode provided with an anode leading-out wire 2 and having a dielectric oxidizing film on the surface thereof, a semiconductor metal oxide layer and a cathode layer are laminated is faced with a mold on an insulating resin 8. In a chip type solid electrolytic capacitor element 1, the joint of an outside anode terminal 4 and an anode leading-out wire is welded by laser from an inclined direction as they are always held to lightly touch. For example, when the anode leading-out wire 2 of the capacitor element 1 is welded with the outside anode terminal 4, the anode leading-out wire 2 and the outside anode terminal 4 are held by a contact terminal 5 so as not to deviate and slip off upward and downward, right and left and the pushing pressure has notinfluence on the characteristic to be 5-20g/mm<2> while a laser beam is irradiated from the two inclined direction of arrow marks A, B.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a tantalum solid electrolytic capacitor.

(Prior art) As a conventional example, FIG. 3 shows a tantalum wire 11 which is an anode lead-out wire and an external anode terminal 1 of a molded chip tantalum solid electrolytic capacitor disclosed in Japanese Utility Model Application Publication No. 59-91726.
Fig. 2 shows an enlarged perspective view of the double-folded welded portion on Fig. 2; In the figure, 13 is a capacitor element, 14 is an insulating plate, and shows a resistance welding method in which an upper electrode terminal 15 and a lower electrode terminal 16 are energized and pressurized. However, recently, laser welding methods have been widely used.

Figure 4 is a front view of the laser welding method disclosed in Japanese Patent Application Laid-Open No. 58-58720, and Figure 5 is a front view of the laser welding method disclosed in Japanese Patent Application Laid-Open No. 58-58720.
9, which is a front view of the laser welding method shown in the publication,
13 is a chip tantalum solid electrolytic capacitor element.

In all laser welding, the tantalum wire is irradiated vertically from the side, but the tantalum wire 11 is free and there is no jig to hold it down. 17 is a laser beam.

(Problems to be Solved by the Invention) In the conventional example described above, during laser welding of the tantalum wire, which is the anode lead-out wire, and the external anode terminal, both may not be welded due to thermal deformation or melting deformation.

In the case of resistance welding, the tantalum wire does not melt, but the external anode terminal tends to melt.If the pressure is increased to several kg/m2, the stress at the base of the neck will increase, causing short circuits and leakage current. There was a drawback that the value increased and the characteristics became poor.

An object of the present invention is to provide a method for manufacturing a tantalum solid electrolytic capacitor that eliminates the conventional drawbacks, reduces stress during welding at the base of the neck, which is the tantalum wire lead-out portion of the capacitor element, and stabilizes laser welding conditions. That's true.

(Means for Solving the Problems) The tantalum solid electrolytic capacitor of the present invention includes a capacitor element including an anode lead-out wire and a laminated anode having a dielectric oxide film on the surface, a semiconductor metal oxide layer, and a cathode layer. In a chip-shaped solid electrolytic capacitor molded and exteriorized with an insulating resin, laser welding is performed from an oblique direction while lightly pressing the joint between the external anode terminal and the anode lead wire so that they are always in contact.

(Function) The above configuration reduces the stress during welding at the neck base, which is the tantalum wire extraction portion of the capacitor element, and stabilizes the laser welding conditions.

(Example) An example of the present invention will be described based on FIGS. 1 and 2. FIG. 1 is a perspective view showing a partial internal structure of a tantalum solid electrolytic capacitor according to the present invention. In the same figure, 1
is a capacitor element, which is made by molding tantalum powder and firing it in a vacuum to form a dielectric oxide film.
An electrolyte layer such as manganese dioxide is laminated on the surface of the capacitor, and 2 is an anode lead wire made of tantalum wire led out from the capacitor element 1, and 3 is an insulating plate made of Teflon or the like. A method of welding the anode lead wire 2 of the capacitor element 1 to the external anode terminal 4 will be explained with reference to FIG. 2, which is an enlarged perspective view. In the figure, the contact terminal 5 supports the anode lead wire 2 and the external anode terminal 4 so that they do not shift vertically or horizontally or come loose while irradiating the laser beam from two diagonal directions indicated by arrows A and B. The pressing pressure is adjusted to 5 to 20 g/2, which hardly affects the properties.

The laser beams from arrow A and arrow B are at 3000°C.
Since the anode lead wire 2 made of tantalum wire with a high melting point can be set so as to be able to irradiate a wide range, the external anode terminal 4
It is easy to adjust the welding conditions. Moreover, both metals are fused and bonded, increasing the fusion strength.

Additionally, when used in vacuum or inert gas,
Since the welding dimension from the capacitor element 1 can be shortened, it is possible to increase the capacity. This method reduces mechanical stress during welding of the insulating plate 3 of Teflon or the like of the capacitor element 1, and improves characteristic defects such as short circuits and increased leakage current values. 6 is an external cathode terminal, 7 is a conductive bonding material, and 8 is a mold exterior resin.

(Effects of the Invention) According to the present invention, by reducing stress during welding of tantalum solid electrolytic capacitors, characteristic defects such as short circuits and increased leakage current values are reduced, welding conditions are stabilized, and problems with welding failure are eliminated. Furthermore, the fusion of the tantalum wire, which has a different melting temperature, and the external anode terminal increases the welding strength, which has a great practical effect.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the internal structure of a tantalum solid electrolytic capacitor according to an embodiment of the present invention, Fig. 2 is an enlarged perspective view of the welded portion, and Fig. 3 is a perspective view showing the internal structure of a tantalum solid electrolytic capacitor according to an embodiment of the present invention. FIG. 4 is a front view showing the laser welding method disclosed in JP-A No. 58-58720, and FIG. 5 is an enlarged perspective view showing the resistance welding method disclosed in JP-A-58-58721. It is a front view showing a laser welding method. DESCRIPTION OF SYMBOLS 1... Capacitor element, 2... Anode lead-out wire, 3...
... Insulating plate, 4... External anode terminal, 5... Contact terminal, 6... External cathode terminal, 7... Conductive bonding material, 8... Mold exterior resin, Arrows A, B...・Laser beam. Patent applicant: Matsushita Electric Industrial Co., Ltd. Figure 4 Figure 5

Claims (1)

[Claims] In a chip-shaped solid electrolytic capacitor in which an anode having an anode lead wire and a dielectric oxide film on the surface, a capacitor element laminated with a semiconductor metal oxide layer and a cathode layer is molded and exteriorized with an insulating resin, an external anode terminal and A method for manufacturing a tantalum solid electrolytic capacitor, characterized in that laser welding is performed from an oblique direction while lightly pressing the bond to the anode lead wire so that it is in constant contact.