TWI761138B - Lead terminal of chip-type electrolytic capacitor, and method for producing chip-type electrolytic capacitor - Google Patents

Abstract

The present invention provides a lead terminal for a chip type electrolytic capacitor and a method for manufacturing the chip type electrolytic capacitor, which can suppress defects caused by metal powder generated during press working to form the lead portion of the lead terminal for a chip type electrolytic capacitor. The lead terminal has a strip-shaped lead portion and a terminal portion joined to one end of the lead portion and connected to the electrode foil of the capacitor element. The lead portion is composed of a metal wire having a coating layer with good solder wettability provided on the outer periphery, and is connected to the terminal portion. The metal wire is punched into a strip shape in a state before the electrode foil, and both surfaces of the lead portion are pressed surfaces during the punching process.

Description

Lead terminal of chip-type electrolytic capacitor, and method for producing chip-type electrolytic capacitor

The present invention relates to a lead terminal of a chip-type electrolytic capacitor and a manufacturing method of the chip-type electrolytic capacitor.

In general, a lead terminal for a chip electrolytic capacitor has a strip-shaped lead portion soldered to a circuit board and a terminal portion provided at one end thereof, and is mounted on the capacitor element of the chip electrolytic capacitor via the terminal portion. The lead portion is formed into a strip shape by pressing a metal wire in the radial direction (Patent Document 1). In addition, in order to secure the reliability of the bonding strength between the lead portion and the circuit board, it may be formed of a metal wire having a coating layer (eg, 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

Invention to solve problem

FIG. 5 is an explanatory diagram of a conventional pressing process of the lead portion. As shown in FIG. 5( a ), a coating layer 512 is provided on the outer periphery of the metal wire 511 forming the lead portion. As shown in FIG.7(b), the metal wire 511 is pinched|interposed between the 1st press die 110 and the 2nd press die 120, and the strip|belt-shaped lead part is formed. When the metal wire 511 is pinched, the cross-section is deformed into an elliptical shape, but at this time, since the coating layer 512 is relatively soft, its thickness becomes the thinnest at the top and bottom of the center of the metal wire 511, and gradually increases to both sides thick.

Since the thickness of the cladding layer 512 increases on both sides, a large amount of metal powder is generated on both sides of the metal wire 511 , and there is a problem that short circuit of the circuit board easily occurs and capacitor characteristics are deteriorated.

The present invention has been made in view of the above-mentioned circumstances, and one of the objects thereof is to suppress defects due to metal powders that are generated at the time of press working to form lead portions of lead terminals for chip-type electrolytic capacitors.

technical solutions to problems

The first invention relates to a lead terminal 4 connected to a capacitor element 3 of a chip type electrolytic capacitor 1 , the lead terminal 4 having a strip-shaped lead portion 41 and a terminal joined to one end thereof and connected to an electrode foil of the capacitor element 3 The lead portion 41 is composed of a metal wire 411 provided with a coating layer 412 having good solder wettability on the outer periphery, and the metal wire 411 is connected before the terminal portion 42 is connected to the electrode foil. 411 is punched into a strip shape, and both surfaces of the lead portion 41 are pressed surfaces during punching.

In addition, the second invention relates to a method of manufacturing a chip-type electrolytic capacitor 1 including a lead terminal 4 having a strip-shaped lead portion 41 and a terminal portion 42 provided at one end thereof, and connected to the terminal portion 42 The capacitor element 3, the method of manufacturing the wafer-type electrolytic capacitor 1 includes: preparing a metal wire 411 of a predetermined length provided with a coating layer 412 having good solder wettability on the outer periphery; punching the metal wire 411 into a tape The step of forming the lead portion 41 in the shape of a strip; the step of removing the metal scraps generated when the metal wire 411 is punched into a strip shape from the lead terminal 4 ; and the electrode foil of the capacitor element 3 A step of connecting the terminal portion 42 .

effect of invention

ADVANTAGE OF THE INVENTION According to this invention, the defect by the metal powder which generate|occur|produces at the time of the press process which forms the lead part of the lead terminal for chip-type electrolytic capacitors can be suppressed.

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

As shown in FIGS. 1 and 2 , a chip-type electrolytic capacitor 1 of the present embodiment includes a bottomed cylindrical container 2 , a capacitor element 3 accommodated in the container 2 , and a pair of lead terminals leading from the capacitor element 3 . 4. The sealing member 5 for closing the opening of the container 2 and the seat plate 6 provided on the side of the opening end 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 stamping a metal wire having a rectangular cross section into a strip shape. In the present embodiment, the metal wire is formed by cutting an elongated CP wire (copper-clad steel wire).

The outer periphery of the metal wire 411 is provided with a coating layer 412 (see FIG. 4 ) composed of a tin plating layer in order to improve the 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 step of forming the lead portion by pressing the metal wire is performed before the terminal portion 42 is attached to the electrode foil of the capacitor element.

In this case, the terminal portion 42 can be attached to the electrode foil after the metal powder generated during the press working of the lead portion 41 is sufficiently removed from the lead terminal 4, so that the metal powder does not easily adhere to the completed chip type electrolytic capacitor. 1, it is possible to suppress short circuit of the circuit board, degradation of capacitor performance, and the like.

The sealing member 5 is formed of rubber or the like, and has a pair of through holes 51 through which the terminal portions 42 are 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 has a pair of through holes 61 through which the lead portions 41 are inserted, and a pair of grooves 62 communicated with the through holes 61 . After the pair of lead portions 41 are inserted into the through holes 61 , they are bent in directions away from each other, and are accommodated in the grooves 62 .

Next, the manufacturing method of the lead terminal 4 is demonstrated.

The lead terminal 4 is manufactured through the following steps. First, an elongated CP wire having a polygonal cross-section provided with the cladding layer 412 on the outer periphery is cut to prepare a metal wire 411 having a length corresponding to the lead portion 41 . Next, the terminal portion 42 is provided at one end of the metal wire 411 . Then, the metal wire 411 is punched to form the 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 punch 110 and the second punch 120 , and plastically processed as shown in FIG. 4( b ) the ribbon. In addition, after processing the metal wire 411 into a strip shape, both sides may be cut off.

The cross-section of the metal wire 411 is quadrangular, so the thickness of the coating layer 412 is not locally thinned on the upper and lower sides of the metal wire 411 during stamping, 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 shown in FIG. 5 , the variation in thickness of the clad layer 412 after being processed in a strip shape is reduced, so that it is possible to suppress a local decrease in solder wettability. As a result, the reliability of the bonding strength of the lead portion 41 to the circuit board is improved.

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 thick on both sides, and metal powder is less likely to be generated, so that the short circuit of the circuit board and the deterioration of the capacitor characteristics can be suppressed.

In addition, this invention is not limited to each embodiment mentioned above.

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

In addition, the metal wire may be formed from a raw 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, when such a manufacturing method is applied to the case where a cross-sectional shape is a shape other than a polygon, the same effect can be acquired also when press-working.

1: Chip type electrolytic capacitors 2: container 3: Capacitor components 4: Lead terminal 4': semi-finished product of lead terminal 5: Sealing parts 6: Seat plate 41: Lead part 42: Terminal part 51: Through hole 61: Through hole 62: pair slot 110: 1st stamping die 111: stamping surface 120: 2nd stamping die 121: stamping surface 411: Metal Wire 412: Cladding 421: Flat part 511: Metal Wire 512: Cladding

FIG. 1 is a perspective view of a chip-type electrolytic capacitor provided with lead terminals of the present invention.

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

FIG. 3 is an explanatory diagram of a method for manufacturing a lead terminal of the present invention.

FIG. 4 is an explanatory diagram of a method for manufacturing a lead terminal of the present invention.

FIG. 5 is an explanatory diagram of a method of manufacturing a lead terminal.

110: 1st stamping die

120: 2nd stamping die

411: Metal Wire

412: Cladding

Claims (2)

A lead terminal connected to a capacitor element of a chip type electrolytic capacitor, The lead terminals are characterized by: having a strip-shaped lead portion and a terminal portion joined to one end thereof and connected to the electrode foil of the capacitor element; The lead portion is composed of a metal wire having a coating layer with good solder wettability provided on the outer periphery, and the metal wire is punched into a strip shape in a state before the terminal portion is connected to the electrode foil, and the Both surfaces of the lead portion are pressed surfaces during press working. A method for manufacturing a chip-type electrolytic capacitor, the chip-type electrolytic capacitor comprising: a lead terminal having a strip-shaped lead portion and a terminal portion provided at one end thereof, and a capacitor element connected to the terminal portion, The manufacturing method of this chip type electrolytic capacitor is characterized in that: A step of preparing a metal wire having a predetermined length provided with a coating layer having good solder wettability on the outer periphery; The step of forming the lead portion by punching the metal wire into a strip; the step of removing metal shavings from the lead terminals that are produced when the metal wire is punched into a strip; and The step of connecting the terminal portion to the electrode foil of the capacitor element.

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