JPH04333209A - Metallized film capacitor - Google Patents

Abstract

PURPOSE:To obtain a metallized film capacitor in which a disconnection failure can be prevented and tan delta characteristics and the like can be improved. CONSTITUTION:A metallized film is formed by laminating a metal thin film by conducting vapor deposition and the like of aluminum on a plastic film of polyphenylene sulfied and the like, and an element 1 is formed by lap-winding the aforesaid metallized film, and a metallized film capacitor, in which a metallicon layer 2, containing aluminum of 80% or more and silicon of 3% or more is characteristically provided on the edge face of the element 1, is obtained.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an unpacked film capacitor.

0002

[Prior Art] In order to make electronic equipment smaller and more functional,
Various electronic components are made into chips. The low melting point of the plastic film used as the dielectric for film capacitors has been an obstacle to chipping, but recently,
Now available.

Film capacitors generally use a metallized film in which a metal thin film is formed by vapor-depositing a metal such as aluminum onto a plastic film, and this metal thin film is used as an electrode. Then, this metallized film is wound, and metallicon is sprayed onto the end face of the wound film to form a capacitor element having a structure as an extraction electrode. As the plastic film, polyethylene terephthalate (melting point: 264° C.) is mainly used. Further, metallicon uses an alloy having a melting point of 160 to 260° C. or a single metal such as Zn or Pb, in accordance with the melting point of the plastic film. Note that the general exterior may be omitted in order to further downsize the film capacitor.

0004

[Problems to be Solved by the Invention] However, when film capacitors are unpacked, for example, metallicon has a melting point of 1.
If an alloy with a temperature of 60 to 260°C is used, when it is soldered to a board, etc. by flow or reflow, it will melt, or even below the melting point, it will melt due to a diffusion reaction and melt into the surrounding solder, resulting in disconnection. There are drawbacks.

[0005] Furthermore, when Zn is used in metallicon, it is easily dissolved by surrounding moisture, resulting in poor connection with the metal thin film formed on the surface of the film, resulting in an increase in tan δ and deterioration of IR characteristics. , there is a drawback that the wire may be disconnected.

Furthermore, when Pb is used as a metallicon, it has poor connectivity with a metal thin film such as aluminum, cannot obtain normal tan δ characteristics in the initial stage, and has the drawback of extremely low withstand current.

An object of the present invention is to provide a film capacitor which can improve the above-mentioned drawbacks, prevent disconnection defects, and improve tan δ characteristics.

[0008]

[Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention provides an element in which a metallized film in which a thin metal film made of aluminum is laminated on a plastic film is wound to form an element, and the end face of the element is coated with metallized film. In layered metallized film capacitors, aluminum 80
% or more, and a metallicon layer containing 3% or more of silicon is provided.

[0009]

[Action] More than 80% aluminum, 3% silicon
Alloys containing the above have good connection with aluminum metal thin films. Furthermore, since this alloy has a solidus temperature of 380° C. or higher, it does not melt during normal soldering. Furthermore, this alloy is stable to moisture and does not leach out.

[0010] If the aluminum content is less than 80%, the hardness increases and the wire cannot be formed into a wire, making it difficult to form a metallicon layer.

Furthermore, when silicon content is less than 3%, the melting point rises to a maximum of 659.8°C, damaging the metal thin film and causing t
There are drawbacks such as an δ defect and poor current resistance.

Furthermore, if the aluminum content is less than 80% and the silicon content is less than 3%, there will be disadvantages when each substance is insufficient, and the bond strength will generally decrease.

[0013]

EXAMPLES The present invention will be explained below based on examples. In Fig. 1, 1 is a highly heat-resistant film such as polyphenylene sulfide film or polyparaphenylene terephthalamide, which is made by vapor-depositing aluminum to form a thin metal film. This is an element with a sealing film wrapped around it. 2 is a first metallicon layer laminated on the end face of this element 1 and directly connected to the metal thin film, and is made of 80% aluminum.
The above is made of metal containing 3% or more of silicon. 3 is a second metallicon layer made of Pb laminated on the first metallicon layer 2, and has a polished surface. 4 is a first layer made of Ni or Cu laminated on the second metallicon layer 3.
This is the plating layer. A second plating layer 5 is laminated on the first plating layer 4 and is made of solder.

Next, the manufacturing method of the above embodiment will be explained. First, the element 1 is formed by winding the metallized film 2 and wrapping a sealing film around the outermost circumference. After forming the element 1, a first metallcon layer 2 is formed on the end face of the element 1 by electric arc spraying using a 1.2φ metal wire made of an alloy containing 80% or more of aluminum and 3% or more of silicon. . Electric arc spraying conditions are: applied voltage is 20V, DC
, the blowing air has a pressure of 5 kg/cm2 and a flow rate of 1.6 m.
3/min, metal wire feed 50mm/sec, spraying distance 2
00mm, and the spraying speed is 50mm/sec. Note that the spraying distance refers to the distance between the tip of the nozzle that sprays air and the end surface of the element. In addition, the thermal spraying speed refers to the rate at which multiple elements 2 are integrated and the edges are treated with metallicon.
This refers to the speed at which the nozzle moves along the end surface. After thermal spraying, Pb
A second metallicon layer 3 is formed on the surface of the first metallicon layer 2 under the same conditions as above using a metal wire of 1.6φ made of . After forming the second metallicon layer 3, excess metallicon is removed using a rotating barrel. Next, apply 80V to the element 1 for a film thickness of 1 μm of the metallized film 2.
, DC voltage is applied for 1 second. After this voltage treatment, the element 1 is impregnated with epoxy resin for 3 hours under vacuum pressure and centrifuged to remove excess epoxy resin. After centrifugation, it is heated at a temperature of 120° C. for 3 hours for temporary hardening, and then heated at a temperature of 170° C. for 16 hours for main hardening. The operations of vacuum pressure impregnation and main curing of the epoxy resin are repeated two to three times. After this operation, the surface of the second metallicon layer 3 is cut and polished using an end mill blade. After polishing, Ni
Alternatively, the first plated layer 4 having a thickness of approximately 50 μm is formed by electroplating Cu. After forming the first plating layer 4, the surface thereof is plated with solder to form the second plating layer 5.

[0015] In addition to Pb, the second metallcon layer is made of Pb/Sn alloy, Pb/Sn/Ag alloy, Pb/Sn
- Zn.Ag.Sb alloy and Sn.Sb.Cu alloy may also be used. However, Pb/Sn/Zn/Ag/Sb alloys dissolve due to diffusion reactions even below their melting point.
It is necessary to sufficiently cover it with the first plating layer. Further, the second metallicon layer may be omitted, and only the first metallicon layer may be used.

[0016]

As described above, according to the present invention, since a metallicon layer containing 80% or more aluminum and 3% or more silicon is directly laminated on the end face of the element, disconnection defects can be prevented and tan δ characteristics can be improved. A metallized film capacitor with improved current resistance and current resistance can be obtained.

[Brief explanation of the drawing]

FIG. 1 shows a cross-sectional view of an embodiment of the invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1...Element, 2...First metallicon layer, 3...Second
metallicon layer.

Claims (1)

[Claims] Claim 1: A metallized film capacitor in which a metallized film in which a metal thin film made of aluminum is laminated on a plastic film is layered and wound to form an element, and a metallicon layer is provided on the end face of this element.
1. A metallized film capacitor comprising a metallicon layer containing 0% or more silicon and 3% or more silicon.