JP5884962B2 - Capacitor manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a capacitor that seals by deforming the vicinity of an opening of an exterior case together with the vicinity of an edge of a sealing body by caulking the vicinity of the opening of the exterior case.

  In general electrolytic capacitors, an electrolytic solution is impregnated with a capacitor element in which an anode foil and a cathode foil to which lead terminals are attached are wound or laminated with a separator interposed therebetween, and the lead terminals are formed in insertion holes formed in a sealing body. Inserted and housed in a bottomed cylindrical outer case made of metal such as aluminum, the opening of the outer case is closed with a sealing body, and the outer case is crimped to seal the outer case. Are to be sealed. This caulking is performed by lateral caulking (drawing process) from the side of the outer case and vertical caulking (curling process) at the opening end, ensuring the airtightness of the electrolytic capacitor by lateral caulking, The sealing body is prevented from coming off by caulking.

  The lead terminal is formed by welding an aluminum wire having a flat portion on one end side and a lead wire (metal wire) having a plating layer on the surface as an external lead wire on the other end side. . From the viewpoint of environmental protection in recent years, lead wires with tin plating are often used to cope with lead-free lead terminals. In the welded portion of the lead wire, Al, Sn, Cu, Fe, and the like are mixed. Particularly, when the aluminum layer is exposed to the outside air, stress acts on the Sn layer due to hydration or oxidation reaction, and a whisker-like shape called whisker is formed. It is known that a crystal is generated. If this whisker falls on the circuit board, there is a risk of shorting the electronic circuit.

  Therefore, in order to prevent the whisker from falling on the substrate, the diameter of the opening portion of the lead terminal insertion hole formed in the sealing body is made smaller than the diameter of the lead terminal lead wire, and the welded portion and the outside are blocked. Thus, whiskers are prevented from scattering (see, for example, Patent Documents 1 and 2). In addition, a storage portion closed with a cylindrical thin film having a gradually decreasing diameter toward the outside of the capacitor is formed in the lead wire through hole (insertion hole) of the sealing rubber (sealing body). By storing the welded portion, whiskers generated in the welded portion are prevented from falling on the substrate (see, for example, Patent Document 3).

JP 2006-295055 A JP 2008-108865 A Japanese Patent Laid-Open No. 2008-251982

  However, in the capacitors described in Patent Documents 1 and 2, when the outer case is vertically crimped and the sealing body is sealed, if the vicinity of the contact portion of the sealing body with the outer case is pressed, the stress The shape of the opening portion of the insertion hole of the sealing body is deformed by this, and the portion of the opening portion of the insertion hole that is close to the exterior case is pulled toward the exterior case side, so that the opening portion of the insertion hole expands and the lead terminal There is a problem that the weld is exposed (see FIG. 9). Further, even in the capacitor described in Patent Document 3, the tubular thin film that closes the storage portion of the sealing rubber (sealing body) is deformed by being pulled by caulking, and the storage portion is opened to the outside. There is a risk that.

The present invention has been made paying attention to such problems, and when the outer case is swaged and the sealing body is sealed, the insertion hole into which the lead terminal is inserted is deformed by the pressing force by swaging. Another object of the present invention is to provide a method for manufacturing a capacitor that prevents exposure of the welded portion of the lead terminal and prevents scattering of whiskers generated from the welded portion.

In order to solve the above-described problem, a method for manufacturing a capacitor of the present invention includes
A lead terminal having a welded portion formed by welding a metal wire and an aluminum wire is connected to the capacitor element, the lead terminal is inserted into an insertion hole formed in the sealing body, and the capacitor element is externally mounted. A method of manufacturing a capacitor that is housed in a case, closes the opening of the outer case with the sealing body, and seals the vicinity of the opening of the outer case by caulking,
The shape of at least the opening of the insertion hole is such that the edge side of the sealing body is built toward the center side of the sealing body with respect to the shape substantially the same as the sectional shape of the metal wire of the lead terminal. in, is formed on differences shape, the shape of the opening of the insertion hole, in Rukoto edge vicinity of the sealing member is to deform by the caulking, cross section shape of the metal wire of the lead terminals It is characterized in to Rukoto substantially the same shape as the.
According to this feature, when the outer case is swaged and the sealing body is sealed, even if the insertion hole into which the lead terminal is inserted is deformed by the pressing force due to the swaging, The shape of the opening of the insertion hole, which was a different shape, is substantially the same as the sectional shape of the metal wire of the lead terminal, and a gap is created between the opening of the insertion hole and the metal wire of the lead terminal. Therefore, exposure of the welded portion of the lead terminal can be prevented, and whisker scattering generated from the welded portion can be prevented. Further, when the outer case is swaged and the sealing body is sealed, even if the insertion hole through which the lead terminal is inserted is deformed by the pressing force by the swaging, the contact between the opening of the insertion hole and the lead terminal is caused by the build-up. Can be maintained. In addition, by appropriately setting the dimensions of the build-up, it is possible to obtain an optimum shape of the opening of the insertion hole according to the elastic modulus of the sealing body, the pressing force by caulking, and the like.

The method for producing the capacitor of the present invention includes:
The shape of at least the opening of the insertion hole is substantially circular, and the edge side of the sealing body in the opening of the insertion hole is bulged toward the center of the sealing body, so that the phase It is characterized that you form a different shape.
According to this feature, the shape of the opening portion of the insertion hole is substantially circular compared to the case where the shape of the opening portion of the insertion hole is a shape such as a square shape having a corner portion. Regardless of the direction in which the opening of the insertion hole is pulled by caulking, it is difficult to create a gap between the opening of the insertion hole and the lead terminal, and the insertion hole can be penetrated to any position of the sealing body. The end edge side of the sealing body at the opening of the insertion hole only needs to be built up, and it is easy to set a site for forming the build up.

The method for producing the capacitor of the present invention includes:
The insertion hole has a storage portion for storing the welded portion, and the shape of the insertion hole is a shape that narrows from the storage portion toward the opening of the insertion hole.
According to this feature, even if the insertion hole has a shape different from the cross-sectional shape of the metal wire of the lead terminal, the lead terminal can be easily inserted from the storage portion side toward the opening of the insertion hole. Mechanical stress applied to the capacitor element through the lead terminal can be reduced. Further, since the welded portion is covered, the welded portion of the lead terminal, which is a site where whiskers are generated, is not exposed to the outside air. Therefore, it is difficult for hydration and oxidation reaction to occur, and the generation of whiskers can be suppressed.

  In the present invention, substantially the same shape means that not only the shape of the opening of the insertion hole deformed by caulking is the same as the shape of the metal wire of the lead terminal, but also the insertion deformed by caulking. A shape having a gap enough to prevent the whisker from dropping between the opening of the hole and the metal wire is also included.

1 is a longitudinal front view showing a capacitor in Example 1. FIG. It is an enlarged vertical front view which shows a sealing body. It is a top view which shows a sealing body. It is a top view which shows the sealing body by which the lead terminal was penetrated. It is an AA cross-sectional top view which shows the sealing body in FIG. 6 is a plan view showing a sealing body in Embodiment 2. FIG. It is a cross-sectional top view which shows the sealing body of the 1st modification corresponding to the AA cross section of FIG. It is a cross-sectional top view which shows the sealing body of the 2nd modification corresponding to the AA cross section of FIG. It is an enlarged vertical front view which shows the conventional sealing body.

  EMBODIMENT OF THE INVENTION The form for implementing the capacitor | condenser which concerns on this invention is demonstrated below based on an Example.

  The capacitor according to the first embodiment will be described with reference to FIGS. Reference numeral 1 in FIG. 1 denotes an electrolytic capacitor to which the present invention is applied. This electrolytic capacitor 1 has an outer case 2 having a substantially bottomed cylindrical shape, and an opening 3 is formed at one end of the outer case 2, and the opening 3 is a sealing body 4 made of a synthetic resin and having a substantially cylindrical shape. Is blocked. The exterior case 2 is made of a metal material such as aluminum, and the sealing body 4 is made of an elastic material having elasticity such as resin rubber.

  As shown in FIG. 1, this electrolytic capacitor 1 has a capacitor element 5 in which a plurality of electrode foils formed of aluminum are wound or laminated with a separator interposed therebetween, and the capacitor element 5 is packaged together with an electrolytic solution. Case 2 is housed. Two lead terminals 6, an anode and a cathode, are connected to the capacitor element 5.

  The lead terminal 6 is formed by welding an aluminum wire 7 connected to the capacitor element 5 and a metal wire 8 (CP wire) led out to the outside. The aluminum wire 7 and the metal wire 8 have a substantially cylindrical shape, and the diameter of the aluminum wire 7 is larger than the diameter of the metal wire 8. A flat portion (not shown) formed in a substantially flat shape by pressing or the like is provided at the lower end of the aluminum wire 7, and this flat portion is connected to the electrode foil of the capacitor element 5. ing.

  The metal wire 8 is made of a mild steel wire as a core material, and a copper coating layer (metal plating layer) obtained by plating copper as a metal material thickly is formed on the outer periphery of the mild steel wire. Further, a tin plating layer (metal plating layer) made of 100% tin as a metal material is formed on the outer periphery thereof. The material constituting the metal wire 8 does not use lead at all, and the material constituting the aluminum wire 7 or the capacitor element 5 does not contain lead at all. Is a lead-free electronic component that does not contain lead and does not adversely affect the natural environment.

  In the welded portion 9 of the lead terminal 6, Al, Sn, Cu, Fe and the like are mixed, and particularly when the aluminum layer is exposed to the outside air, stress acts on the Sn layer (tin layer) due to hydration or oxidation reaction. It is known that a beard-like crystal called whisker is generated. That is, the welded portion 9 between the metal wire 8 and the aluminum wire 7 in the lead terminal 6 is a whisker generation site.

  As shown in FIG. 2, the sealing body 4 has two insertion holes 10 through which the lead terminals 6 are inserted. 2 will be described as the front side of the sealing body 4, and the lower side of the paper will be described as the back side of the sealing body 4. After the lead terminal 6 is connected to the capacitor element 5, the lead terminal 6 is inserted into the insertion hole 10 from the back surface side of the sealing body 4, and the metal wire 8 of the lead terminal 6 is led out to the front surface side of the sealing body 4. Yes.

  A storage portion 11 for storing the welded portion 9 of the lead terminal 6 is formed in the internal space of the insertion hole 10, and whiskers generated in the welded portion 9 are enclosed in the storage portion 11. ing. In addition, the shape of the insertion hole 10 is a shape which narrows toward the opening part 12 side (surface side of the sealing body 4) of the insertion hole 10 from the accommodating part 11. As shown in FIG.

  As shown in FIG. 3, the shape of the opening 12 of the insertion hole 10 on the surface side of the sealing body 4 is substantially circular, but is different from the sectional view of the metal wire 8 in the lead terminal 6. Is formed. While the cross-sectional shape of the metal wire 8 is a perfect circle, the shape of the opening 12 of the insertion hole 10 is a shape in which a part of the perfect circle is cut out.

  Specifically, the opening portion 12 of the insertion hole 10 is formed with a built-up portion 13 that builds up the edge T side of the sealing body 4 in the opening portion 12 toward the center C side of the sealing body 4. Has been. Furthermore, the edge of the built-up portion 13 is formed in a substantially linear shape in plan view. By forming the build-up portion 13, the shape is different from the cross-sectional view shape of the metal wire 8. The diameter of the opening 12 of the insertion hole 10 is slightly smaller than the diameter of the metal wire 8.

  When the lead terminal 6 is inserted into the insertion hole 10 formed in the sealing body 4, the diameter of the opening 12 of the insertion hole 10 is increased so as to match the sectional view of the metal wire 8 of the lead terminal 6. However, in this state, the built-up portion 13 of the insertion hole 10 is in a state of pressing the metal wire 8.

  As shown in FIG. 2, with the lead terminal 6 inserted in the insertion hole 10 formed in the sealing body 4, the capacitor element 5 is inserted from the opening 3 formed at one end of the exterior case 2, The capacitor element 5 is stored in the outer case 2. And the opening part 3 of the exterior case 2 is obstruct | occluded with the sealing body 4, and the edge 14 vicinity of the opening part 3 of the exterior case 2 is crimped.

  This caulking process includes lateral caulking (drawing process) for narrowing the side surface of the exterior case 2 in the vicinity of the opening 3 over the entire circumference and the inner edge of the edge 14 on the opening 3 side of the exterior case 2 over the entire circumference. It is performed by vertical caulking (curling process) in which the edge 14 on the opening 3 side of the exterior case 2 is bent near the edge T of the sealing body 4. In addition, the airtightness of the exterior case 2 is ensured by lateral caulking, and the sealing body 4 is prevented from coming off by vertical caulking.

  As shown in FIGS. 2 and 4, the tip end portion of the edge 14 bent inward of the outer case 2 by vertical caulking bites into the vicinity of the edge T of the sealing body 4. Due to the pressure, the surface side of the sealing body 4 is pulled from the center C side to the edge T side. Due to this pulling force, the above-described built-up portion 13 moves to the edge T side of the sealing body 4, and the shape of the opening 12 of the insertion hole 10 is substantially the same as the cross-sectional shape of the metal wire 8 of the lead terminal 6. Become. In addition, a gap can be prevented from being generated between the opening 12 of the insertion hole 10 and the metal wire 8 of the lead terminal 6. Note that the built-up portion 13 of the insertion hole 10 does not press the metal wire 8. Furthermore, the dimensions of the built-up portion 13 are appropriately set according to the elasticity of the sealing body 4 and the pressing force during caulking.

  Next, a capacitor according to Example 2 will be described with reference to FIG. Note that the same configuration as that of the first embodiment is omitted.

  As shown in FIG. 6, the sealing body 4a has two insertion holes 10a through which the lead terminals 6 are inserted. The insertion hole 10a is formed in the vicinity of the edge T of the sealing body 4a. In addition, the cross-sectional view shape of the metal wire 8 of the lead terminal 6 used in the second embodiment is a perfect circle like the first embodiment.

  The shape of the opening 12a of the insertion hole 10a formed in the vicinity of the edge T of the sealing body 4 is substantially circular, but is different from the cross-sectional shape of the metal wire 8 in the lead terminal 6. Is formed. Whereas the cross-sectional shape of the metal wire 8 is a perfect circle, the shape of the opening 12a of the insertion hole 10a changes in the curvature of a part of the perfect circle.

  Specifically, a built-up portion 13a is formed in the opening 12a of the insertion hole 10a so that the edge T side of the sealing body 4a in the opening 12a is built up toward the center C side of the sealing body 4a. Has been. Furthermore, the built-up portion 13a is formed in a crescent shape in plan view. By forming this build-up portion 13 a, the opening 12 a of the insertion hole 10 a has a shape different from the cross-sectional shape of the metal wire 8.

  When caulking is performed in Example 2, the surface side of the sealing body 4a is pulled from the center C side to the edge T side by vertical caulking. By this pulling force, the built-up portion 13a of the opening 12a of the insertion hole 10a formed in the vicinity of the edge T of the sealing body 4a moves to the edge T side of the sealing body 4a, and the opening 12a of the insertion hole 10a The shape is substantially the same as the sectional shape of the metal wire 8 of the lead terminal 6.

  The dimension of the build-up part 13a is appropriately changed according to the penetration position of the insertion hole 10a in the sealing body 4a, and the dimension of the build-up part 13a is set so as to increase as the distance from the center C of the sealing body 4a increases. The

  As described above, in the first and second embodiments, the shape of the opening 12 of the insertion hole 10 is different from the sectional view of the metal wire 8 of the lead terminal 6. The shape of the opening 12 is such that the vicinity of the edge T of the sealing body 4 is deformed by caulking, so that the shape of the opening 12 becomes substantially the same as the sectional shape of the metal wire 8 of the lead terminal 6. When the sealing body 4 is sealed by crimping, the insertion hole 10 through which the lead terminal 6 is inserted is deformed by the pressing force by the crimping, which is different from the sectional view shape of the metal wire 8 of the lead terminal 6. The shape of the opening 12 of the insertion hole 10, which was the shape to be formed, is substantially the same shape as the sectional view of the metal wire 8 of the lead terminal 6, and the opening 12 of the insertion hole 10 and the metal wire 8 of the lead terminal 6 In this way, no exposure of the welded portion 9 of the lead terminal 6 is prevented without causing a gap therebetween. It can prevent scattering of whiskers et occur.

  Further, the above-described caulking process is performed by bending the edge 14 of the opening 3 of the outer case 2 inward and pressing the edge 14 of the opening 3 of the outer case 2 near the edge T of the sealing body 4. Due to the caulking, the sealing body 4 is pulled from the center C side to the edge T side by this vertical caulking, and the shape of the opening 12 of the insertion hole 10 is led by this pulling force. The shape of the metal wire 8 of the terminal 6 can be substantially the same as the cross-sectional shape of the metal wire 8, so that no gap is generated between the opening 12 of the insertion hole 10 and the metal wire 8 of the lead terminal 6.

  The shape of the opening 12 of the insertion hole 10 is such that the end T side of the sealing body 4 faces the center C side of the sealing body 4 with respect to the shape substantially the same as the sectional view of the metal wire 8 of the lead terminal 6. By having the build-up portion 13 that builds up and builds up, the shape of the lead terminal 6 is different from the cross-sectional view of the metal wire 8, so that the outer case 2 is crimped and the sealing body 4 is sealed In this case, even if the insertion hole 10 through which the lead terminal 6 is inserted is deformed by the pressing force by caulking, the built-up portion 13 can maintain the contact between the opening 12 of the insertion hole 10 and the lead terminal 6. . In addition, by appropriately setting the dimensions of the build-up portion 13, the shape of the opening portion 12 of the insertion hole 10 can be optimized according to the elastic modulus of the sealing body 4, the pressing force by caulking, and the like.

  Moreover, in the said Example 1 and 2, the shape of the opening part 12 of the insertion hole 10 comprises a substantially circular shape, and the edge T side of the sealing body 4 in the opening part 12 of the insertion hole 10 is a sealing body. 4 having the build-up portion 13 that is built up toward the center C side, the shape different from the cross-sectional shape of the metal wire 8 of the lead terminal 6 is formed, so that the opening of the insertion hole 10 is formed. Compared to the case where the shape of 12 is a shape such as a square shape having corners, the shape of the opening 12 of the insertion hole 10 is substantially circular, so that the insertion hole 10 can be Regardless of the direction in which the opening 12 is pulled, a gap is hardly formed between the opening 12 of the insertion hole 10 and the metal wire 8 of the lead terminal 6, and the insertion hole 10 is placed at any position on the sealing body 4. Even if it penetrates, the edge T side of the sealing body 4 in the opening part 12 of the insertion hole 10 is built up. It suffices to 13, easily setting a portion for forming a cladding portion 13.

  Further, the insertion hole 10 has a storage portion 11 for storing the welded portion 9 of the lead terminal 6, and the shape of the insertion hole is narrowed from the storage portion 11 toward the opening portion 12 of the insertion hole 10. Therefore, even if the insertion hole 10 has a shape different from the cross-sectional shape of the metal wire 8 of the lead terminal 6, the lead terminal 6 is inserted from the storage portion 11 side toward the opening portion 12 of the insertion hole 10. This makes it easier to reduce mechanical stress applied to the capacitor element through the lead terminal during insertion. In addition, since the welded portion is covered, the welded portion of the lead terminal, which is a whisker generation site, is not exposed to the outside air, so that hydration and oxidation reactions are unlikely to occur, and the generation of whiskers can be suppressed.

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications and additions within the scope of the present invention are included in the present invention. It is.

  For example, in the above embodiment, an electrolytic capacitor is exemplified as the capacitor, but the capacitor to which the present invention is applied is not limited to this, and can be applied to various capacitors and capacitors such as an electric double layer capacitor and an electrochemical capacitor.

  Moreover, in the said Example, although the tin plating layer applied to the metal wire 8 is 100%, the content of tin in the plating layer is not limited to 100%, but a tin plating layer comprising at least 90% tin or more. If it is. Furthermore, as a metal plating layer, you may form a plating layer not only with a tin plating layer but with other metal materials, such as a silver plating layer and a gold plating layer. Also, other metal materials can be added to the plating layer. For example, the plating layer which added metals, such as bismuth, to tin is mentioned. In addition, the content of tin, silver, or gold in the metal plating layer can be set as appropriate within a solderable range.

  Moreover, in the said Example, although the contact of the opening part 12 and the lead terminal 6 is maintained, it is not restricted to this, The clearance | interval which is a grade which a whisker does not fall between the opening part 12 and the metal wire 8 of the lead terminal 6 May be provided. For example, if the gap between the crimped opening 12 and the lead terminal 6 is about 40 μm or less, whiskers that cause a short circuit can be prevented from dropping onto the substrate.

  In each of the above embodiments, the lead-out portion of the lead terminal 6 is arranged on the edge side that is symmetric with respect to the center portion C of the sealing body 4. However, the present invention is not limited to this. You may arrange in the position. In this case, the dimensions of the built-up portion 13 of the opening 12 may be changed depending on the arrangement position.

  Moreover, in the said Example, the buildup part 13 is formed only in the opening part 12 of the insertion hole 10, and as shown in FIG. 5, the buildup part 13 is not formed in the inner surface of the insertion hole 10, Not only this but the built-up part 15 may be formed in the whole penetration hole 10 similarly to the opening part 12. As shown in FIG. For example, as shown in the modified example 1 of FIG. 7, the built-up portion 15 may be formed only on the edge side of the sealing body 4 in the same manner as the built-up portion 13 of the opening 12. Not only this but as shown in the modification 2 of FIG. 8, you may form the buildup parts 15 and 16 in the whole inner surface of the insertion hole 10. As shown in FIG. At this time, the build-up portion 15 on the end edge side of the sealing body 4 on the inner surface of the insertion hole 10 and the build-up portion 16 formed on the other inner surface of the insertion hole 10 may be formed separately.

  Furthermore, in the said Example, although the cross-sectional view circular sealing body was used, it is good also not only as this but cross-sectional view square shape. Moreover, although the cross sectional view shape of the metal wire 8 is a perfect circle shape, the shape is not limited to this, and the cross sectional view shape may be a square shape.

DESCRIPTION OF SYMBOLS 1 Capacitor 2 Exterior case 3 Opening part 4 Sealing body 5 Capacitor element 6 Lead terminal 7 Aluminum wire 8 Metal wire 9 Welding part 10 Insertion hole 11 Storage part 12 Opening part 13 Overlaying part 14 Edge 15 Overlaying part

Claims (3)

A lead terminal having a welded portion formed by welding a metal wire and an aluminum wire is connected to the capacitor element, the lead terminal is inserted into an insertion hole formed in the sealing body, and the capacitor element is externally mounted. A method of manufacturing a capacitor that is housed in a case, closes the opening of the outer case with the sealing body, and seals the vicinity of the opening of the outer case by caulking,
The shape of at least the opening of the insertion hole is such that the edge side of the sealing body is built toward the center side of the sealing body with respect to the shape substantially the same as the sectional shape of the metal wire of the lead terminal. in, is formed on differences shape, the shape of the opening of the insertion hole, in Rukoto edge vicinity of the sealing member is to deform by the caulking, cross section shape of the metal wire of the lead terminals method for producing a capacitor characterized by be Rukoto substantially the same shape as the. The shape of at least the opening of the insertion hole is substantially circular, and the edge side of the sealing body in the opening of the insertion hole is bulged toward the center of the sealing body, so that the phase method for producing a capacitor according to claim 1, characterized that you form a different shape. The said insertion hole has a storage part which stores the said welding part, The shape of this insertion hole is made into the shape which narrows toward the opening part of the said insertion hole from this storage part. 2. A method for producing a capacitor as described in 2.

Images