JPH0216569B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a chip-shaped electrolytic capacitor. In recent years, electronic devices have become smaller and thinner due to advances in semiconductor technology such as ICs and LSIs, and automatic insertion and mounting technology for electronic components has become more widespread. Various chip types have been devised in the field of capacitors, some of which are already in practical use. However, since electrolytic capacitors use electrolyte, it is difficult to make them into chips.
Its structure was also complex. For this reason, conventionally, as shown in Fig. 1, the drawer lead 2
The element 1 is wound between a pair of aluminum electrode foils connected to each other with a separator interposed therebetween, and the element 1 is impregnated with an electrolytic solution, stored in the inner case 3 and sealed, and then connected to the external terminal metal electrode 4 to the drawer lead 2. , those molded with exterior resin 5 and the like were well known. Since the conventional chip-shaped electrolytic capacitor manufactured as described above has a connecting part between the drawer lead 2 and the external terminal metal electrode 4, there are restrictions on the finished dimensions of the product due to the manufacturing process. As shown in Fig. 1, the lead 2 penetrates the side wall surface of the interior resin case 3, so even though various measures have been taken to maintain internal airtightness, a perfect one has not yet been obtained, and it is necessary to improve the electrical characteristics. It also had many drawbacks, including limitations. The present invention eliminates the above-mentioned drawbacks and provides a chip-shaped electrolytic capacitor that is small and highly heat resistant. The present invention will be explained below with reference to the embodiments shown in FIGS. 2 and 3. Figure 2 is a perspective view of a chip-shaped electrolytic capacitor during the manufacturing process, and Figure 3 is a cross-sectional view of the chip-shaped electrolytic capacitor. The capacitor element 1 formed by turning is inserted into a heat-shrinkable resin tube 6 with excellent heat resistance such as Teflon, and after inserting an elastic body 7 such as rubber into the pull-out leads 2 at both ends, the capacitor element 1 is heated and shrunk. Element 1 and elastic body 7 such as rubber are tightened and fixed. Thereafter, a liquid resin 8 such as epoxy or urethane is applied to the openings at both ends and hardened. In addition,
Instead of the elastic body 7, a sealing body made of thermosetting or thermoplastic resin may be used. The product thus manufactured is further molded with exterior resin 5. Next, as shown in FIG. 3, a conductive layer 9 is formed by applying silver paste or the like to the lead-out leads 2 at both ends and their end faces and hardening.
Then, an electroless plating process made of a solderable metal such as nickel or copper is applied to the conductive layer 9.
After forming an electroless plating layer 10 on the lead-out lead 2, a solder plating layer 11 is formed to complete the process. According to the method for forming the external electrodes described above, the base can be treated with either non-ferrous metal or resin. Therefore, the extraction lead 2 can be pulled out with the aluminum connected to the electrode foil, and not only does it not have a connecting part such as welding of the extraction lead unlike conventional products, but it also has no shrinkage force of the heat-shrinkable resin tube 6. Since the entire wound capacitor element 1 is tightened, the distance between the wound anode foil and cathode foil electrodes is narrowed, and the electrical characteristics can also be improved. Further, since the lead-out portion of the lead-out lead 2 is kept doubly airtight by the elastic body 7 or the sealing body 7 and the liquid resin 8, an extremely reliable chip-shaped electrolytic capacitor was obtained. Next, based on the example above, the rating is 25V, 3.3μF.
We manufactured a chip-shaped electrolytic capacitor with a temperature of 260℃.
After immersing the product in molten solder for 10 seconds, the product was left in an atmosphere at 85°C with 50VDC applied, and its changes over time were measured. The results compared with conventional products are shown in the table.

[Table] As is clear from the table, it was confirmed that the products of the present invention exhibit extremely stable characteristics compared to conventional products even in life tests under high temperature loads. As mentioned above, the chip-shaped electrolytic capacitor of the present invention has a structure in which the capacitor element is tightened by the contraction force of the heat-shrinkable resin tube, airtightness is maintained by the elastic body of the sealing part or the sealing body and the resin layer, and the drawer is It becomes possible to integrate the leads with the solder plating layer that forms the external terminals, making it possible to manufacture capacitors with excellent characteristics, which is of great industrial and practical value.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional chip-shaped electrolytic capacitor, FIG. 2 is a perspective view of a chip-shaped electrolytic capacitor during the manufacturing process of the present invention, and FIG. 3 is a cross-sectional view of an embodiment of the chip-shaped electrolytic capacitor of the present invention. It is a diagram. 1: Capacitor element, 2: Output lead, 5,
8: resin, 6: heat-shrinkable resin tube, 9: conductive layer, 10: electroless plating layer, 11: solder plating layer.

Claims (1)

[Claims] 1 A capacitor element is formed by making an anode foil and a cathode foil face each other with a separator interposed therebetween, and the element is impregnated with an electrolytic solution, and the lead leads led out from the element in two opposite directions are made of an elastic material such as rubber or resin. It is inserted into a sealing body such as a heat-shrinkable resin tube, and is heat-shrinked.A resin layer is formed to surround the tube, and a conductive layer is placed on the protruding parts of the drawer leads at both ends of the resin layer. Metsuki layer,
A chip-shaped electrolytic capacitor characterized in that an electrode is formed by successively forming solder plating layers, and the electrode is connected to the above-mentioned lead.