TW201814746A - Lead terminal manufacturing method, wafer type electrolytic capacitor, and semi-finished product of lead terminal - Google Patents

Abstract

The present invention relates to a method for manufacturing a lead terminal, a wafer-type electrolytic capacitor, and a semi-finished product of a lead terminal, suppresses a local decrease in solder wettability of a lead portion of a lead terminal for a wafer-type electrolytic capacitor, and suppresses generation of metal powder. A method for manufacturing a lead terminal (4) having a strip-shaped lead portion (41) and a terminal portion (42) provided at one end thereof, and the lead terminal (4) is mounted to the terminal portion via the terminal portion A capacitor element (3) of a wafer-type electrolytic capacitor (1), the method comprising a step of preparing a metal wire (411) with a polygonal cross section provided with a coating layer (412) having good solder wettability on an outer periphery, and 411) A step of forming a lead portion (41) by performing a press working.

Description

   Method for manufacturing lead terminal, wafer-type electrolytic capacitor, and semi-finished product of lead terminal   

The present invention relates to a method for manufacturing a lead terminal for a wafer type electrolytic capacitor, a wafer type electrolytic capacitor, and a semi-finished product of a lead terminal.

Generally, a lead terminal for a wafer-type electrolytic capacitor has a strip-shaped lead portion soldered to a circuit board and a terminal portion provided at one end thereof, and the capacitor element is mounted to the wafer-type electrolytic capacitor via the terminal portion. The lead portion is formed into a band shape by press-working a metal wire having a circular cross-section in a radial direction (Patent Document 1). In addition, in order to ensure the reliability of the soldering strength between the lead portion and the circuit board, it may be formed by a metal wire provided with a coating layer (for example, a tin plating layer) having good solder wettability on the outer periphery.

Prior art literature

Patent Document 1: Japanese Patent Application Laid-Open No. 11-26327

Conventionally, the cross section of the metal wire forming the lead portion is circular. Therefore, after the metal wire is press-processed, the thickness of the cladding layer provided on the outer periphery may be locally reduced, which may impair solder wettability.

FIG. 7 is an explanatory diagram of a pressing process of a conventional lead portion. As shown in FIG. 7 (a), the cross section of the metal wire 511 forming the lead portion is circular, and a cladding layer 512 is provided on the outer periphery. As shown in FIG. 7 (b), a metal wire 511 is sandwiched between the first punch 110 and the second punch 120 to form a strip-shaped lead portion. When the metal wire 511 is sandwiched, the cross section deforms into an oval shape, but at this time, because the coating layer 512 is soft, its thickness becomes the thinnest at the top and bottom of the metal wire 511 and gradually changes to both sides. thick.

As described above, if the thickness of the cladding layer 512 is locally reduced, solder wettability is greatly reduced in this portion, and reliability of solder strength may be impaired. In addition, since the thickness of the cladding layer 512 becomes thicker on both sides, a large amount of metal powder is generated on both sides of the metal wire 511, and there is also a problem that a short circuit of the circuit board is likely to occur and the characteristics of the capacitor are lowered.

The present invention has been made in view of the above circumstances, and an object thereof is to suppress a local decrease in solder wettability of a lead portion of a lead terminal for a wafer type electrolytic capacitor and to suppress generation of metal powder.

In order to achieve the above object, the first invention relates to a method of manufacturing a lead terminal 4 having a strip-shaped lead portion 41 and a terminal portion 42 provided at one end thereof, and the lead terminal 4 is mounted to the terminal portion 42 via the terminal portion 42. The capacitor element 3 of the wafer-type electrolytic capacitor 1 includes a step of preparing a metal wire 411 having a polygonal cross-section provided with a coating layer 412 having good solder wettability on an outer periphery, and a step of punching the metal wire 411. Process of forming the lead portion 41.

The second invention relates to a wafer-type electrolytic capacitor including the lead terminal 4 manufactured by the first invention.

The third invention relates to a semi-finished product 4 ′ of a lead terminal 4 having a strip-shaped lead portion 41 and a terminal portion 42 provided at one end thereof, and the lead terminal 4 is mounted to a wafer type via the terminal portion 42. In the capacitor element 3 of the electrolytic capacitor 1, the semi-finished product of the lead terminal includes a metal wire 411 with a polygonal cross-section extending from the terminal portion 42 and provided with a coating layer 412 having good solder wettability on the outer periphery. The metal wire 411 can be punched Processed and plastically deformed into the shape of the lead portion 41

According to the present invention, it is possible to suppress a local decrease in solder wettability of a lead portion of a lead terminal for a wafer-type electrolytic capacitor, and to suppress generation of metal powder.

1‧‧‧Chip Electrolytic Capacitor

2‧‧‧ container

3‧‧‧ capacitor element

4‧‧‧lead terminal

4’‧‧‧ Semi-finished products of lead terminals

5‧‧‧Sealing parts

6‧‧‧ seat plate

41‧‧‧Leader

42‧‧‧Terminal

51‧‧‧through hole

61‧‧‧through hole

62‧‧‧Slot

110‧‧‧The first stamping die

111‧‧‧ stamping surface

120‧‧‧ 2nd stamping die

121‧‧‧ stamping surface

130‧‧‧ recess

411‧‧‧metal wire

412‧‧‧ cladding

412b‧‧‧ convex strip

421‧‧‧ Flat

511‧‧‧metal wire

512‧‧‧ coating

FIG. 1 is a perspective view of a wafer-type electrolytic capacitor including a lead terminal according to the present invention.

FIG. 2 is a longitudinal sectional view of the wafer-type electrolytic capacitor of FIG. 1.

3 is a perspective view of a semi-finished product of a lead terminal according to the present invention.

FIG. 4 is an explanatory diagram of a first embodiment of a method of manufacturing a lead terminal according to the present invention.

FIG. 5 is an explanatory diagram of a second embodiment of the lead terminal manufacturing method of the present invention.

FIG. 6 is an explanatory diagram of a lead terminal manufacturing method of a comparative example.

FIG. 7 is an explanatory diagram of a conventional lead terminal manufacturing method.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, a wafer-type electrolytic capacitor 1 according to this embodiment includes a bottomed cylindrical container 2, a capacitor element 3 housed in the container 2, and a pair of lead terminals that are output from the capacitor element 3. 4. A sealing member 5 that closes the opening of the container 2 and a seat plate 6 provided on the open end side of the container 2. The container 2 is formed of a thin metal plate, and the opening end is bent inward to fix and support the sealing member 5.

The lead terminal 4 has a strip-shaped lead portion 41 bent in an L-shape, and a terminal portion 42 is provided at one end thereof. The lead portion 41 is formed by punching a metal wire having a rectangular shape in cross section into a band shape. In this embodiment, a metal wire is formed by cutting an elongated CP wire (copper-clad steel wire).

As shown in FIG. 3, a terminal portion 42 is provided at one end of the metal wire 411 to manufacture a semi-finished product 4 ′ of the lead terminal. The terminal portion 42 of the semi-finished product 4 ′ is mounted on the electrode foil of the capacitor element 3, and the capacitor element 3 is mounted on After the container 2, the metal wire 411 is press-processed into a strip shape to form a lead terminal 4.

A coating layer 412 (see FIG. 4) made of a tin plating layer is provided on the outer periphery of the metal wire 411 in order to improve solder wettability. The terminal portion 42 is formed by pressing a rod-shaped member made of aluminum or the like, and has a flat portion 421 connected to the capacitor element 3 at one end of the terminal portion 42. One end of the metal wire 411 is connected to the other end of the terminal portion 42 by welding or the like, and the metal wire 411 extends from the terminal portion 42.

The sealing member 5 is formed of rubber or the like, and has a pair of through holes 51 through which the terminal portion 42 is inserted. The seat plate 6 is formed of an insulating material and is fixed to the open end of the container 2 by bonding or the like.

The seat plate 6 includes a pair of through holes 61 through which the lead portion 41 is inserted, and a pair of grooves 62 communicating with the through holes 61. After being inserted into the through-hole 61, the pair of lead portions 41 are bent in directions away from each other and are accommodated in the groove 62.

Next, a method for manufacturing the lead terminal 4 will be described.

The lead terminal 4 is manufactured by the following steps. First, an elongated CP wire having a polygonal cross-section having a coating layer 412 provided on the outer periphery is cut, and a metal wire 411 having a length corresponding to the lead portion 41 is prepared. Next, a terminal portion 42 is provided at one end of the metal wire 411. Then, the metal wire 411 is press-processed to form a lead portion 41.

In the step of forming the lead portion 41, as shown in FIG. 4 (a), the metal wire 411 is sandwiched between the first stamping die 110 and the second stamping die 120, and plastically processed as shown in FIG. 4 (b). Ribbon. Alternatively, after the metal wire 411 is processed into a strip shape, both sides thereof may be cut.

The cross section of the metal wire 411 is a quadrangle. Therefore, the thickness of the cladding layer 412 does not become locally thin on both sides of the metal wire 411 during press processing, and the thickness is substantially uniform over the entire length in the width direction.

Therefore, as compared with the metal wire 511 having a circular cross section as shown in FIG. 7, the variation in the thickness of the cladding layer 412 after the strip-shaped processing is reduced, so that it is possible to suppress a local decrease in solder wettability. This improves the reliability of the soldering strength of the lead portion 41 to the circuit board.

In addition, since the variation in the thickness of the cladding layer 412 is reduced, the thickness of the cladding layer 412 can be suppressed from becoming thicker on both sides, and metal powder is less likely to be generated. Therefore, it is possible to suppress short circuit of the circuit board and decrease in capacitor characteristics.

Next, a second embodiment of the present invention will be described.

As shown in FIG. 5 (a), in the present embodiment, a plurality of groove-shaped recesses 130 are provided on the pressing surface 111 of the first pressing die 110 and the pressing surface 121 of the second pressing die 120. These recesses 130 are provided in parallel so as to extend in the axial direction of the metal wire 411 (the direction orthogonal to the paper surface in FIG. 5), and the cross sections of the punched surfaces 111 and 121 are wavy.

By providing such a plurality of recesses 130, when the metal wire 411 is sandwiched between the first and second punches 110 and 120, as shown in FIG. 5 (b), the coating layer 412 extends along the plurality of recesses. 130. The cross section is changed into a wave shape, and since a plurality of protruding lines 412b extending in the axial direction of the metal wire 411 are formed, the dross 412a cannot easily protrude to both sides of the metal wire 411.

On the other hand, as shown in FIG. 6, when a plurality of groove-shaped recesses 130 are not provided on the pressing surface 111 of the first pressing die 110 and the pressing surface 121 of the second pressing die 120, it is the same as the case of FIG. 5. Compared with this, the dross 412a is more likely to protrude to both sides of the metal wire 411, so the metal powder is easily spilled.

By providing the recess 130 shown in FIG. 5 in the first and second stamping dies 110 and 120, metal powder is not easily spilled, so that it is possible to further suppress short circuit of the circuit board and degradation of capacitor characteristics.

The present invention is not limited to the above embodiments.

For example, the cross-sectional shape of the metal wire may be a polygon other than a quadrangle.

The metal wire may be formed of a material other than the CP wire.

In addition, instead of the tin plating layer, a coating layer made of another material having good solder wettability may be provided on the outer periphery of the metal wire.

In addition, the step of forming a lead portion by pressing a metal wire may be performed before the terminal portion is mounted on the electrode foil of the capacitor element. In this case, since the metal powder generated during the punching process of the lead portion can be sufficiently removed from the lead terminal, the terminal portion can be attached to the electrode foil. Therefore, the metal powder cannot be easily attached to the completed wafer-type electrolytic capacitor. Further, it is possible to further suppress a short circuit of a circuit board, a decrease in capacitor performance, and the like. In addition, when such a manufacturing method is applied to a case where a metal wire having a cross-sectional shape other than a polygon is punched, the same effect can be obtained.

Moreover, the shape of the recessed part provided in the press surface of a 1st press die and the press surface of a 2nd press die may be a shape other than a groove shape, and the number of recessed parts may be an odd number.

The recessed portion may be provided only on one of the first punching die and the second punching die. In addition, when a metal wire having a cross-sectional shape other than a polygon is punched, a recess can be provided in at least one of the punching surface of the first punching die and the punching surface of the second punching die to obtain the same Effect (dross does not easily protrude to both sides of the metal wire, and metal powder is not easily generated).

Claims (7)

    A method for manufacturing a lead terminal, the lead terminal (4) having a strip-shaped lead portion (41) and a terminal portion (42) provided at one end thereof, and the lead terminal (4) passing through the terminal portion (42) A capacitor element (3) mounted on a wafer-type electrolytic capacitor (1), wherein the method for manufacturing a lead terminal includes a polygonal cross-sectional polygonal shape provided with a coating layer (412) having a good solder wettability on an outer periphery. A step of metal wire (411); and a step of forming the lead portion (41) by pressing the metal wire (411).         The method for manufacturing a lead terminal according to claim 1, wherein the step of forming the lead portion (41) is performed before mounting the terminal portion (42) to the capacitor element (3).         The method for manufacturing a lead terminal according to claim 1 or 2, wherein in the step of forming the lead portion (41), between the first punching die (110) and the second punching die (120) The metal wire (411) is sandwiched, and a recess is provided on at least one of the pressing surface (111) of the first pressing die (110) and the pressing surface (121) of the second pressing die (120). (130).         The method for manufacturing a lead terminal according to claim 3, wherein the recessed portion (130) has a groove shape extending in an axial direction of the metal wire (411).         The method for manufacturing a lead terminal according to claim 4, wherein a plurality of the recesses (130) are provided in parallel.         A wafer-type electrolytic capacitor including a lead terminal (4) manufactured by the manufacturing method according to any one of claims 1 to 5.         A semi-finished product of a lead terminal, the lead terminal (4) having a strip-shaped lead portion (41) and a terminal portion (42) provided at one end thereof, and the lead terminal (4) passing through the terminal portion (42) The capacitor element (3) attached to the wafer-type electrolytic capacitor (1), the semi-finished product (4 ') of the lead terminal is characterized by having a solder wetting extending from the terminal portion (42) and provided on the outer periphery. The polygonal metal wire (411) of the clad layer (412) with good properties can be plastically deformed into the shape of the lead portion (41) by press working.