JPS6233732B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a capacitor whose exterior is formed by thermally welding a laminate film in which an outer layer film containing aluminum powder and an inner layer film are laminated together, and a method for manufacturing the capacitor. In general, the exterior of various types of capacitors such as aluminum electrolytic capacitors, tantalum electrolytic capacitors, plastic film capacitors, paper capacitors, and ceramic capacitors houses the capacitor element in a container made of metal such as aluminum or brass, or synthetic resin such as phenol, polypropylene, or polyethylene. Alternatively, the capacitor element may be coated with a synthetic resin such as epoxy or polyester. However, when the capacitor element is housed in a container made of metal or synthetic resin, a considerably large gap is created between the container and the capacitor element, resulting in a large-sized capacitor element, and the housing operation is complicated and requires many man-hours. In addition, when coating with synthetic resin, it is difficult to adjust the thickness of the coating layer, resulting in uneven thickness, resulting in non-uniformity, and the surface of the coating layer is uneven, deteriorating the appearance. Furthermore, as in Japanese Patent Publication No. 46-35653, there is a proposal to heat and pressurize a thermosetting resin sheet by aligning the concave portions with each other using a mold, but since a thermosetting resin sheet is used, heating is not necessary. The pressure must be maintained for a certain period of time, which adds unnecessary thermal stress to the capacitor element, causing characteristic deterioration. Furthermore, recently, there has been a proposal to package a capacitor element by thermally welding a composite film made by laminating a plastic film onto a metal foil, as disclosed in Japanese Patent Application Laid-open No. 56-54032, but this method causes short circuits between the terminals through the metal foil. In addition, the metal foil is exposed at the cut cross section of the composite film at the edge of the welded part, and when mounted on a printed circuit board, the exposed metal foil part is likely to come into contact with other peripheral parts or peripheral parts via the exposed metal foil part, and furthermore, The terminal lead-out portion had drawbacks such as the risk of short-circuiting the conductor circuit on the printed circuit board. In order to eliminate the above-mentioned drawbacks, the present invention wraps a capacitor element in a laminate film made by laminating an outer layer film containing aluminum powder and an inner layer film, and thermally welds the capacitor element to form an exterior. The present invention aims to provide a capacitor with improved gas permeability and stable electrical characteristics, and a method for manufacturing the same. An embodiment of the present invention will be described below with reference to the drawings. That is, as shown in FIG.
2 above and below the plurality of capacitor elements 2 with
A welded portion 4 is formed by arranging a sheet or folded laminate film 3 and thermally welding each capacitor element 2 simultaneously or one by one continuously on four or three sides around the plurality of capacitor elements 2. Then, the capacitor element 2 is wrapped and sealed with the laminate film 3 to form an exterior. As shown in FIG. 2 or 3, the laminate film 3 is made by blending aluminum powder 6 inside an outer layer film 5 to form an integrally thin film, and then laminating an inner layer film 7 thereon. The outer layer film 5 is made of polyethylene terephthalate, polyamide, etc., which have good abrasion resistance, weather resistance, chemical resistance, and heat resistance.
The outer layer film 5 is made of one or two thermoplastic films such as polycarbonate, polypropylene, polyethylene, polysulfone, polyvinylidene fluoride, polyacetal, polyethylene fluoride, polyethylene naphthalate, and polybutylene terephthalate. At this time, 25 to 50% by weight of scaly aluminum powder 6 of 100 to 325 meshes is mixed in advance into the resin pellets and stretched using a method such as an inflation method, T-die method, melt extrusion method, or tenter method. The aluminum powder 6 is embedded in the outer layer film 5 and integrated into the outer layer film 5. The inner layer film 7 is made of vinyl acetate, polyethylene, polypropylene, ionomer (polyolefin-methacrylic acid ester copolymer), polyphenylene sulfide, polyethylene terephthalate, polyvinylidene fluoride, etc., which have good thermal adhesion and chemical resistance. It is made of one or two types of plastic films and is laminated integrally with the outer layer film 5. Heat welding depends on temperature
This is done using a heat sealer such as a hot plate or an indenter on the top and bottom of the laminate film 3 at a temperature of 100 to 400℃, a pressure of 10 to 50 kg/ ^cm2 , and a time of 0.1 to 6 seconds. Sonic welders, friction welders, high frequency welders, impulse welders, etc. may be used. In the thermal welding, the inner layer film 7 is softened and melted using a heat sealer, and the terminal 1, the inner layer film 7, and the mating surfaces of the inner layer film 7 are welded together. The inner layer film 7, which is involved in direct welding, must have a melting point lower than the outer layer film 5 by about 10°C or more, which contains aluminum powder 6, and should be selected in combination. The outer layer film 5
Select a thickness within the range of 50 to 150μ. Then, a welded part 4 is formed by thermal welding, and the welded part 4 is cut from the middle between the plurality of sealed capacitor elements 2 to form individual capacitors as shown in FIG. 4 or 5, or the welded A perforation or notch is provided in the middle of part 4. The perforations and cuts may be provided at the same time as the welded portion 4 is formed, or may be provided after the welded portion 4 is formed. In this case, when the capacitor is mounted on a circuit board and used, it is cut from the perforation or notch. Furthermore, the welded part 4
If the width dimension A is narrow, peeling occurs in the welded portion 4, the sealing performance decreases, and changes in electrical properties such as capacitance and tan δ become large. Therefore, it is effective to set it to at least 1 mm or more. By wrapping and sealing the capacitor element 2 with the laminate film 3 consisting of the outer layer film 5 and the inner layer film 7 containing aluminum powder 6 as described above, insulation protection treatment of the lead-out portion of the terminal 1 is unnecessary. Since the laminate film 3 contains aluminum powder 6, the gas-liquid permeability of the laminate film 3 is poor, so the moisture resistance of the capacitor is improved. Further, the aluminum powder 6 is not continuous like metal foil, but is compounded inside the outer film 5 in a complicated manner, so that there is no short circuit between the terminals 1. Next, an example of comparison of characteristics between the embodiment of the present invention and conventional reference examples () and () is shown in a table. Example is a laminate film made of 25μ polyethylene terephthalate - 30% by weight of aluminum powder of 200 mesh - 100μ ionomer heat welded, Reference example () is a laminate film made of 25μ polyethylene terephthalate - 100μ ionomer heat welded, Reference Example () is 12
A laminate film made of μ polyethylene terephthalate, 20 μ aluminum foil, and 100 μ ionomer is heat welded. Both heat welds were performed at a temperature of 160°C, a pressure of 20 Kg/cm ² , and a time of 2 seconds to reduce the width of the welded part to 1.0 Rated 50WV, DC in mm
It is a 3.3μF aluminum electrolytic capacitor.

[Table] As is clear from the table, the examples are reference examples ()
It can be seen that the characteristics are improved compared to (), and in particular, the initial short-circuit failure rate is significantly reduced, and the characteristics show stable characteristics with little change after the high temperature and high humidity load test. As described in detail above, the present invention wraps a capacitor element with a laminate film made by laminating an outer layer film containing aluminum powder and an inner layer film, and heat-welds the capacitor element to form an exterior, thereby improving the gas-liquid permeability of the laminate film. Therefore, it is possible to provide a capacitor and a method for manufacturing the same, which have improved moisture resistance without permeation of the driving electrolyte or gas, eliminate short-circuit defects, and have stable characteristics.

[Brief explanation of the drawing]

The drawings are all explanatory diagrams of the present invention, and Fig. 1 is a plan view showing an example of heat-welding a plurality of capacitor elements with a laminate film, Fig. 2 is a sectional view showing an example of a laminate film, and Fig. 3 is a laminate. FIG. 4 is a sectional view showing another example of the film, FIG. 4 is a plan view showing an example of a capacitor cut into individual pieces, and FIG. 5 is a plan view showing another example of the capacitor. DESCRIPTION OF SYMBOLS 1... Terminal, 2... Capacitor element, 3... Laminate film, 4... Welding part, 5... Outer layer film, 6
...Aluminum powder, 7...Inner layer film.

Claims (1)

[Claims] 1. A plurality of capacitor elements to which terminals are attached;
A laminate film formed by laminating an outer layer film containing aluminum powder and an inner layer film arranged above and below the capacitor element and surrounding the capacitor element, and a welded part formed around the capacitor element by thermally welding the laminate film. A capacitor characterized by comprising: 2. The capacitor according to claim 1, wherein the width of the welded portion is set to at least 1.0 mm. 3 means for attaching terminals to a plurality of capacitor elements; means for arranging a laminate film in which an outer layer film containing aluminum powder and an inner layer film are laminated above and below the capacitor elements; and a means for thermally welding the laminate film. 1. A method for manufacturing a capacitor, comprising: means for forming a welded portion by cutting the welded portion; and means for cutting the welded portion from the middle. 4. Means for attaching terminals to a plurality of capacitor elements, means for arranging a laminate film in which an outer layer film containing aluminum powder and an inner layer film are laminated above and below the capacitor elements, and a means for thermally welding the laminate film. 1. A method for manufacturing a capacitor, comprising: means for forming a welded portion, means for providing a perforation or notch in the middle of the welded portion, and means for cutting from the perforation or notch.