JPH0855757A - Series-type film capacitor - Google Patents

Abstract

PURPOSE:To enhance the mounting strength of the leader of a lead, stabilize connection, simplify a manufacturing process and enhance efficiency by interposing a film piece between a lead wire and metal foil and welding it under pressure. CONSTITUTION:Vapor deposited electrode layers 1A, 2A are formed at predetermined intervals in the direction of the length of metallized film 1, 2 and are oppositely disposed so that a part of the deposited electrode layer alternately overlappes. A RET film 3 is piled up and wound between the metallized films 1, 2 and 2, 1, and metal foil 5A, 5B, 5C and lead wires 6A, 6B, 6C are welded under pressure through film pieces 7A, 7B, 7C 9 to 38mum thick Lead leader electrodes 4A to 4C brought into contact with the vicinity of both ends of the width direction of the metal foil 5A to 5C are inserted into the start end, the finish end and the intermediate position of windings to form a capacitor element. The width L1 and the length L2 of the metal foil 5A to 5C and the width L3 and the length L4 of thermoplastic film pieces 7A to 7C are formed into the size of L1>L3 and L2>L4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage series type film capacitor (hereinafter simply referred to as a film capacitor).
It is about.

[0002]

2. Description of the Related Art Conventionally, a high voltage film capacitor of this type has been constructed by connecting a plurality of capacitor elements in series inside a capacitor element. FIG. 6 shows a structure of a conventional film capacitor. FIG. 3 is a developed cross section of the element, and FIG. 3 is an appearance of the capacitor element.
Is a round shape, and (b) and (c) are flat shapes.

In FIG. 6, a plurality of electrode layers 1A and 2A are formed on the metallized films 1 and 2 in an island shape at predetermined intervals in the lengthwise direction of the dielectric film, and lead extraction electrodes 4A, 4B and 4C. In addition, the electrodes are wound so as to face each other so that a part of the electrodes are alternately overlapped with each other, and lead wires 6A, 6B, 6C are provided at the start and end of the winding and at any intermediate position.
Is provided to form a capacitor element 11, and a resin exterior 12 is applied.

In the film capacitor having the above-mentioned structure, a plurality of capacitor elements are connected in series to increase the voltage of the capacitor as a whole, and further, the film capacitor is packaged by being dipped in a resin such as an epoxy resin to improve the electrical characteristics. Is being stabilized.

In the method of resin coating, a plurality of capacitor elements 11 are hung on a jig using lead wires 6A, 6B or 6C, immersed in a liquid resin, pulled up, and then heat-cured to be solidified. Further, in order to complete the resin coating more completely, it is dipped in a liquid resin under reduced pressure, and this is repeated a plurality of times. FIG. 5 shows a state in which the capacitor element 11 is hung on a jig and before being immersed in resin, and the lead wires 6A, 6B (6C) of the capacitor element are taped to the metallic taping jig 13 with the tape 14.

[0006]

Usually, the lead wire is φ0.
An aluminum foil having a thickness of 4 to 0.7 mm and a thickness of 5 to 7 μm is used as the metal foil, and the lead wire and the aluminum foil are welded to each other as shown in FIG. 4C, and before the resin is solidified in the resin coating step. However, when external stress is applied to the lead wire, the aluminum foil is torn near the welded portion and a defect often occurs in the process of breaking the wire.

From the above, the conventional method of suspending with one lead wire as shown in FIG. 5 (a), however, many lead wire disconnection defects occurred.
As shown in (b), the load was reduced by taping the two lead wires, but the lead wire failure was not eliminated. Further, in the taping method of suspending with two lead wires, the two lead wires cannot have the same size, and one of them requires an extra length to be folded and suspended.
Further, there are many drawbacks in that the inspection cannot be performed in the taping state as it is after the resin coating, a step of cutting the lead wire from the taping jig is required, and the mechanization is disadvantageous and labor saving is difficult.

As a countermeasure against the above-mentioned drawbacks, FIG.
As shown in (d), the metal foil 5A, 5B, 5C is laminated with the plastic film 9 to prevent the metal foil from breaking, and is hung with one lead wire as shown in FIG. 5 (a). Although a method of lowering it has also been attempted, the laminated foil 10 cannot be processed during winding and must be processed in advance and prepared, and the thickness of the metal foil 5A, 5B,
Since it is more than twice as large as 5C, there is a drawback that the capacitor element becomes large.

[0009]

DISCLOSURE OF THE INVENTION The present invention is intended to provide a film capacitor which solves the above-mentioned drawbacks, and leads 6A, 6B and 6C as shown in FIGS.
The strip-shaped thermoplastic film pieces (hereinafter simply referred to as film pieces) 7A, 7B, 7C having limited width, length and thickness dimensions are interposed in a part of the metal foils 5A, 5B, 5C for welding the lead wires. Lead extraction electrode 4 with pressure welding
It is characterized by using A, 4B, and 4C.

That is, metallized films (1) and (2) having a plurality of island-shaped electrodes (1A) (2A) provided at predetermined intervals in the length direction of the dielectric film, and the metallized film (1) And (2),
A series type film capacitor comprising one or more dielectric films (3) each laminated between (2) and (1), a lead extraction electrode, and a resin sheath, which is made of metal foil. The width L1 and the length L2 and the width L3 and the length L4 of the strip-shaped thermoplastic film piece are formed to have dimensions L1> L3 and L2> L4, and the lead extraction electrode has a metal foil and a lead wire with a thickness of 9 ~ 38μm in the range of the strip-shaped thermoplastic film piece is welded and contacted in the vicinity of both ends of the width direction of the metal foil, the winding start end and winding end of the metallized film (1), or A series-type film capacitor which is arranged at a winding start end, a winding end, and an arbitrary intermediate position, and is formed by winding the metallized film, the dielectric film, and the lead extraction electrode, and having a resin sheath (12).

[0011]

In the capacitor element having the above structure, the film piece is melted and welded during welding by pressure welding with the film piece interposed between the lead wire and the metal foil without increasing the volume. Weld to metal foil and lead wire. At the same time, the lead wires are brought into contact with each other near both ends of the metal foil in the width direction.

[0012]

Embodiments of the film capacitor of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a main part of a lead extraction electrode of a film capacitor of the present invention,
FIG. 2 is a developed sectional view of a capacitor element which is an embodiment of a film capacitor using the three lead wires of the present invention. The metallized films 1 and 2 are, for example, a polyethylene terephthalate film (hereinafter simply referred to as a PET film) having a width of 60 mm as a dielectric film, and a plurality of vapor-deposited electrode layers 1A and 2A are formed in an island shape at predetermined intervals in the longitudinal direction and vapor-deposited. The PET films 3 are arranged so as to face each other so that a part of the electrode layers are alternately overlapped, and the metallized film 1
And 2 and 2 and 1 are overlapped and wound, and the metal foils 5A, 5B, 5C and the lead wires 6A, 6B, 6C are welded through the film pieces and the metal foils 5A, 5B, 5
Lead extraction electrode 4 contacted near both ends in the width direction of C
A, 4B, and 4C were inserted into the winding start end, the winding end, and the intermediate position to form a capacitor element. In this capacitor element, two capacitors are formed between the lead wires 6A and 6B with the lead wire 6C being common. Then, the width L1 and the length L2 of the metal foils 5A, 5B and 5C and the width L3 and the length L4 of the strip-shaped thermoplastic film pieces 7A, 7B and 7C.
Are formed to have dimensions L1> L3 and L2> L4.

FIG. 4 (a) is a cross-sectional explanatory view of the main part of the lead extraction electrode of the present invention. The metal foils 5A, 5B, and 5C are aluminum foil having a thickness of 7 μm, a width of 50 mm, and a length of 1000 to 1500 mm, and strip-shaped film pieces 7A, 7B, and 7C are PET film pieces having a width of 40 mm and a length of 70 mm. Lead wire 6A, 6 with a diameter of 0.5 mm
When B and 6C are placed and spot welding is performed, the film piece is crushed and broken at the welding portion, and the lead wire is embedded in the film piece and welded to the aluminum foil. The PET film piece is melted by the welding heat at this time, and at the same time, the lead wire and the aluminum foil are welded to mechanically protect the welded portion, and the lead wire is in contact with both ends in the width direction of the metal foil. Therefore, disconnection of the lead wire weld is prevented.

FIG. 4 (b) shows another embodiment of the present invention, in which the film piece 7 is added under the same conditions as in FIG. 4 (a).
A, 7B, and 7C are PET films having the fusion agent layers 8A, 8B, and 8C on the surface in contact with the metal foil (aluminum foil).

There are three types of samples, two types of film capacitors based on FIGS. 4 (a) and 4 (b) and a conventional film capacitor. All samples have a 12-series electrode structure and a rated voltage of 35 kV-DC. 3000pF + 3000
pF.

Sample A has the structure of the lead extraction electrode of the present invention shown in FIG. 4 (a) according to the above-mentioned embodiment, and the film parts 7A, 7B, 7C of the lead extraction electrode have a thickness of 6,
9, 12, 25, 38 and 50 μm. Sample B has the structure of the lead extraction electrode of the present invention shown in FIG. 4 (b) according to another embodiment described above, and the strip-shaped film pieces 7A, 7B, and 7C of the lead extraction electrode have a fusion agent layer on the surface. Have
The thickness is the same as that of the sample A. Sample C is a conventional film capacitor and the structure of the lead extraction electrode is shown in FIG. 4 (c).
Therefore, the film piece according to the present invention is not used. Sample D is another conventional film capacitor and has the structure of the lead extraction electrode shown in FIG. 4 (d), which is a 19 μm laminated foil (7 μm aluminum foil with 12 μ over the entire surface).
m PET film was laminated).

Ten samples of each of the samples A, B, and C were prepared for each sample level, and the lead wire tensile strength (tensile rupture) of the capacitor element before resin coating was compared. Figure 7
Shows the result of the lead wire tensile strength, in which the vertical axis plots the tensile strength (kgf) of the lead wire and the horizontal axis plots the thickness of the strip-shaped film piece of the lead extraction electrode.

The results of the above test show that the samples A and B having the strip-shaped film pieces of the present invention intervened have lead wires different from those of the conventional film capacitor sample C having no strip-shaped film pieces. It became clear that the tensile strength was significantly improved. However, the effect is slightly different depending on the thickness of the strip-shaped film piece to be interposed and is 9 to 38 μm.
The m-thick one is the most effective and stable. That is, within the above range, it is found that the tensile strength of the lead wire of the conventional film capacitor is almost three times as high. However, when the thickness is 6 μm or less, the strength is almost double that of the conventional film capacitor, and when it exceeds 50 μm, the variation in the strength becomes large.

According to the above results, the effects are almost the same in the sample A and the sample B, and the strip-shaped film piece of the sample B has an advantage that it is easily heat-welded to hold it at the welding position of the metal foil during winding. is there.

Next, the capacitor elements of Samples A, B, and C were taped with a single lead wire and suspended, and a resin sheath was applied, but the disconnection failure of the lead wire weld was investigated.
Samples A and B of the present invention prepared 100 capacitor elements each using a strip-shaped film piece of 12 μm and a conventional capacitor element of sample C, and hung them by taping with one lead wire 6C. The step of immersing the capacitor element in a liquid epoxy resin under a reduced pressure, pulling it up, and thermosetting it to complete the resin coating was completed. The lead wire 6C of this film capacitor element had no disconnection defect in the samples A and B of the present invention, but in the conventional sample C, 13% occurred, and the capacitor element came off from the lead wire and dropped. was there. In this way, with the structure of the lead extraction electrode of the present invention, it is possible to tap and suspend with one lead wire.

Next, the volumes of the capacitor elements of Samples A, B, C and D were compared. Another conventional sample D is 15% larger than the conventional sample C, but the sample A of the present invention is
Or B was equivalent to sample C. This is because the strip-shaped film piece is inserted into only a part of the metal foil.

As described above, according to the present invention, it is possible to eliminate the disconnection of the welded portion in the resin coating process and to stabilize the welded portion of the lead wire without increasing the volume ratio of the capacitor element. . Furthermore, by making the strip-shaped film pieces shorter than the width of the metal foil, even if welding of the lead wire and the metal foil is insufficient, contact is secured near both ends in the width direction.

In the embodiment, the capacitor element using the lead-out electrodes at the winding start end, the winding end and the intermediate position is shown, but the same applies to the winding start end and the winding end two points. Also, since the lead extraction electrode of this film piece can be processed during winding,
The same effect can be obtained even when applied to only the lead wire used for taping, that is, when applied to at least one of the lead extraction electrodes 4A, 4B, and 4C.
It is included in the gist of the present invention.

Further, the dielectric film and the film piece are not limited to the polyester film, and thermoplastic films such as polypropylene, polystyrene, polycarbonate, and polyphenylene sulfide can be applied. Further, the number of dielectric films, the number of electrode series of metallized films, the configuration of the position of the lead extraction electrode to be inserted at an arbitrary intermediate position, the shape of the capacitor element, and the like are not limited to those in the above embodiment. .

[0025]

According to the film capacitor of the present invention, the welded portion of the metal foil and the lead wire is reinforced without increasing the volume of the capacitor element, and the breakage of the metal foil near the lead wire welded portion can be prevented. Therefore, it is possible to suspend and tap with one lead wire in a manufacturing process such as a resin exterior, and the manufacturing process is simplified, the efficiency is improved, and the yield is improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a lead extraction electrode of a film capacitor of the present invention.

FIG. 2 is a developed cross-sectional view of a capacitor element that is an example of a serial film capacitor of the present invention.

FIG. 3 is an external perspective view of a conventional series type film capacitor element and the present invention.

4A and 4B are cross-sectional views illustrating a structure of a main part of a lead extraction electrode, where FIGS. 4A and 4B are examples of the present invention, and FIGS. 4C and 4D are conventional examples.

FIG. 5 is a diagram showing a state in which a series type film capacitor element is taped and suspended.

FIG. 6 is a developed sectional view of a conventional series-type film capacitor element.

FIG. 7 is a diagram showing the tensile strength of a lead wire of a series film capacitor.

[Explanation of symbols]

 1, 2 Metallized film 3 Dielectric film 4A, 4B, 4C Lead extraction electrode 5A, 5B, 5C Metal foil 6A, 6B, 6C Lead wire 7A, 7B, 7C Strip-shaped thermoplastic film piece 8A, 8B, 8C Heat Fusing agent layer of plastic film piece 9 Plastic film 10 Laminated foil 11 Capacitor element 12 Resin exterior 13 Taping jig 14 Tape

Claims (1)

[Claims] 1. A metallized film (1) and a metallized film (2) having a plurality of island electrodes (1A) (2A) provided at predetermined intervals in the length direction of a dielectric film. And (2), a series type film capacitor consisting of one or more dielectric films (3) each laminated between (2) and (1), a lead extraction electrode, and a resin sheath. Yes, the width of the metal foil L
1, the length L2 and the width L3 of the strip-shaped thermoplastic film piece,
The length L4 is formed to have dimensions L1> L3 and L2> L4,
Moreover, the lead extraction electrode has a metal foil and a lead wire with a thickness of 9 to
It is welded through the strip-shaped thermoplastic film pieces in the range of 38 μm and is contacted in the vicinity of both ends in the width direction of the metal foil, and the winding start end and winding end of the metallized film (1), or the winding end. The metallized film, the dielectric film, and the winding end and the winding end and any intermediate positions,
A series film capacitor that is made by winding the lead extraction electrode and winding it in a resin sheath (12).