JPS5834912A - Method of sheathing solid electrolytic condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for packaging a solid electrolytic capacitor, and in particular to improving the coverage of the root portion of a patented external lead member with a resin material when a water-repellent coating is formed on the external lead member. be.

In general, this type of solid electrolytic capacitor is made by press-molding metal powder having a valve action into a cylindrical shape and sintering the capacitor element A, and a metal wire having a valve action is attached to the anode lead B in advance, as shown in Part 1. The first external lead member C is welded to the lead-out portion of this anode lead B, and the second external lead member is attached to a capacitor element).
Solder the electrode lead layer E formed on the circumferential surface of A, and then attach the main layer containing the capacitor element to the resin material F.
It is covered with

Incidentally, the capacitor element A is coated with the resin material F by, for example, a dipping method as shown in FIG. That is, first, as shown in FIG.
', to a level such that it is completely immersed. Normally, this resin material F' has a viscosity of 20,000C!
Immediately after the immersion, the immersion level of the capacitor element A is further deepened, as shown in FIG.

Then, the entire circumferential surface of capacitor element A is covered with resin material F'
completely covered by. Then, the capacitor element (A) is pulled up and heat treated to complete the packaging.

However, when pulling up the capacitor element A from the resin material F', the immersion level of the capacitor element A into the resin material F' was deeper than necessary. Because the resin material F' existing between the second external lead members C and D hangs down, the first. The resin material F' is applied thinly to the second external lead members C and D, so that the appearance characteristics are significantly impaired. In addition, as shown in FIG. 3, when the printed board H is mounted, the resin material G creeps up and protrudes to the back surface of the printed board H. Second external lead members C, D and F.

The reliability of soldering with the lint conductor is also impaired.

On the other hand, as shown in Figure 2 (a), if the immersion time of the capacitor A is made long enough, the liquid level of the resin material F' will gradually rise until finally returns to the dotted line position shown in the figure. Therefore, if you pull up capacitor A at this point, the first. The creeping up of the resin material F' onto the second external lead members C and D can be suppressed to a level that does not pose a practical problem.
However, it has the disadvantage of significantly reducing workability, and has not yet been put into practical use.

Therefore, various solutions have been proposed in the past. For example, in Japanese Patent Application Laid-Open No. 55-145828, prior to immersing a component body having a plurality of external lead members extending in the same direction in a resin material, a chain-like material such as wax, stearic acid, paraffin, etc. A water-repellent coating is formed on the component body and the external lead member by immersing the component body in a chlorinated hydrocarbon solution in which a hydrocarbon or higher fatty acid is dissolved in such a manner that the external lead member is immersed, and then , discloses a method for packaging electronic components in which a coating on undesired portions is removed by immersing the component body in a solvent such as trichlorethylene or trichloroethane.

According to this method, even if the immersion level of the component body into the resin material is deep as shown in FIG. Because of this, the resin material is repelled and undesirable creep-up and adhesion can be effectively suppressed.

By the way, when this method is applied to, for example, the above solid electrolytic capacitor, the first. Second external lead members C, D
Although it is possible to effectively suppress the resin material F from creeping up and adhering to the resin material F, the root portion of the second external lead member is not sufficiently covered with the resin material F, as shown in FIG. 4, for example. A problem arises in that not only the appearance but also the moisture resistance is significantly impaired.

To explain this point in detail, when the capacitor element A is immersed in the resin material F' and pulled up, the resin material F/ present between the first and second external lead members C and D hangs down. In particular, since the first external lead member C has a bent portion in the vicinity of the top surface of the capacitor element 1, the resin material F' can be physically held in this portion. And it won't droop any more than necessary.

However, since the second external lead member is configured in a straight shape, it does not have any function of preventing the resin material F' from hanging down. For this reason, together with the water-repellent effect of the water-repellent coating, the base portion of the second external lead member is not sufficiently covered with the resin material F, which not only impairs the appearance characteristics but also damages the second external lead member. The bending force acting on the external lead member 2 may cause cracks in the resin material F at the base of the external lead member F, resulting in a significant loss of moisture resistance.

In view of these points, the present invention provides the eleventh aspect. To provide a method for packaging a solid electrolytic capacitor in which the root portion of a second external lead member can be reliably covered with wood without impairing the effect of preventing a resin material from creeping up to the second external lead member. One packaging method will be explained below with reference to FIGS. 5 to 10.

First, as shown in FIG. 5, a metal wire having a valve action is planted in advance as a positive HV-dope 2 in a capacitor element 1 which is made by press-molding metal powder having a valve action into a cylindrical shape and sintering it. A first external lead member 3 formed in an L shape is welded to the lead-out portion 2a of the anode lead 2 so that the bent portions 8a intersect. Then, one end 4a of the second external lead member 4 formed in a straight shape is soldered to an electrode lead layer 5 formed on the curved surface of the capacitor element 1 via an oxide layer, a semiconductor layer, and a graphite layer. still,
1st. The second external lead element 3.4 is led out in the same direction.

Next, this capacitor structure is immersed in a water-repellent member so that the upper part of the bent portion 3a of the first external lead member 3 is at the immersion level. After being pulled up, the capacitor element 1 and the first capacitor element 1 are heated as shown in FIG. A water-repellent coating 6 is formed on the second external lead member 3.4.

Next, as shown in FIG. 7, the capacitor structure is heated to a predetermined temperature, and the bent portion 3a of the first external lead member 3 is applied to the resin powder 7' having the substantially flat floating surface 7a1. Immerse so that the area near is the immersion level. The resin powder 7' is stored in an upper space 10 which divides the dipping tank 8 into two vertically by a partition plate 9 having small holes. A floating state is achieved by blowing out a more uniform electric body. The resin powder 7' that has come into contact with the capacitor structure is melted and adhered to the capacitor structure. Then, the capacitor structure is made of resin powder 7
By pulling it up from '' and heat-treating it, the first coating layer 7 is formed as shown in FIG.

Next, as shown in FIG. 9, this capacitor structure is immersed in a resin material 11' having thixotropic properties sufficiently deep so that the first coating layer 7 is completely immersed. Then, the entire peripheral surface of the capacitor element (first coating layer) is wetted with the resin material 11' in a short period of time, but the first. Near the liquid level of the second external lead members 8, 4, the resin material 11'
It will be in a state where it is flipped. Then, when the capacitor structure is pulled up from the resin material 11', the first. At the same time, the resin material 11' existing between the second external lead members 3.4 hangs down. The resin material 11' that is in contact with the second external lead members 8, 4 also hangs down. Thereafter, by heat treatment, a second coating layer 11 is formed as shown in FIG. 10, completing the exterior packaging.

In this way, the first. Since the water-repellent coating 6 is formed on a desired portion of the second external lead member 8.4 by a dipping method, when the capacitor structure is immersed in the resin material 11'r and pulled up, the first. The resin material 11' attached to undesired parts of the second external lead members 3 and 4 is removed from the first external lead member 11'. Second external lead member 3
, 4 together with the resin material 11' existing between them, the resin material 11' is repelled and hangs down in an appropriate amount.

For this purpose, 1. It is possible to almost eliminate the creeping up and adhesion of the resin material 11' to the second external lead member 3.4, and the first. second external lead member 3,
4. Soldering to printed conductors can significantly reduce defects.

In addition, a resin material 11' is provided on the entire circumferential surface of the capacitor element 1.
Since the first coating layer 7 of resin powder 7' is formed so as to sufficiently cover the root portion of the second external lead member 4 prior to the immersion sheathing with the resin powder 7', the capacitor structure is coated with the resin material 11'. Even if the pull-up is higher, the presence of the first coating layer 7 will cause the first. Resin material 11' between the second external lead members
does not sag any more than necessary. For this reason, the root portion of the second external lead member 4 is reliably covered with the resin material 11', and not only the appearance characteristics but also the moisture resistance can be significantly improved.

Next, specific examples will be described. A 0.5φ tank wire (anode lead) was installed in advance on the capacitor element, which was made by press-molding and sintering tantalum powder into a cylindrical shape with a diameter of 8 cm and a height of 4 m, and was bent into an L shape. Round wire diameter is 0
．． A first external lead member with a wire diameter of 0.5φ and a straight shape is welded to the anode lead at a distance of 1.5 mm from the top surface of the capacitor element. External lead member to electrode extraction layer,
Soldering is performed so that the distance from the first external lead member is 5 mm. Next, this capacitor structure was converted into Daiwa IJ-(FS-126) manufactured by Daikin Corporation.
The upper part of the external lead member 5 ml away from the bent part is immersed at the immersion level, and after raising the temperature to 4+, it is heated to form a water-repellent coating of a fluorine-based compound. Next, the capacitor structure is heated to 150° C. and immersed in epoxy resin powder having a flat floating surface so that the bent portion of the first external lead member is at the immersion level. After raising, 150
Cure by heating for an hour. Next, the capacitor structure was made to have thixotropic properties and a viscosity of 4000.
The first external lead member is immersed in 00 PS epoxy resin so that the upper part 8WII++ apart from the bent part is at the immersion level, and after being pulled up, heat treatment is performed to obtain a tantalum solid electrolytic capacitor.

In this capacitor, the first layer of the resin material (second coating layer). The climbing height to the second external lead member is the first. The average height of the resin material present between the second external lead members from the lowest position is Orttx (0, 2 to -o, a
), and no trouble occurred during mounting on a printed board. Further, the root portion of the second external lead member was not undesirably exposed from the second coating layer, and the moisture resistance could be sufficiently increased.

However, in conventional examples, it is difficult to form a water-repellent film.
A creeping adhesion occurred, and approximately 8% of soldering defects occurred after mounting on a printed board. In addition, although creep-up adhesion was not observed in the conventional example in which a water-repellent coating was simply formed, the root portion of the second external lead member
It was exposed to a larger extent than the coating layer, and not only the appearance characteristics but also the moisture resistance were significantly impaired.

In addition, in the present invention, the capacitor element can be made of a wire rod, a plate material, etc. in addition to metal powder, and its shape can also be set as appropriate. Also, 1st. In addition to wire rods, the second external lead member may be formed by punching out a plate. In particular, the bent portion of the first external lead member may be mechanically bent, or the plate may be formed into an approximately L shape. It can also be constructed by punching out.

As described above, according to the present invention, the first. without impairing the effect of preventing the resin material from creeping up to the second external lead member.
The root portion of the second external lead member can be reliably covered with the resin material, and moisture resistance can be improved.

[Brief explanation of the drawing]

Figure 1 is a side sectional view of a conventional solid electrolytic capacitor, Figure 2 is a side sectional view explaining the resin packaging method, Figure 3 is a side sectional view showing how it is mounted on a printed board, and Figure 4 is a side sectional view of a conventional solid electrolytic capacitor. Side sectional view of a solid electrolytic capacitor, which is the premise of the present invention, FIG.
Fig. 10 is an explanatory diagram of the method of the present invention; Fig. 5 is a side sectional view of the capacitor structure; Fig. 6 is a side sectional view showing the state of formation of the water-repellent coating; Fig. 7 is a diagram of the capacitor structure. FIG. 8 is a side sectional view showing the state of formation of the first coating layer; FIG. 9 is a side sectional view showing the state of the capacitor structure immersed in the resin material; FIG. 10 is a side sectional view showing a completed state of the exterior. Figure 7 (υ)
(shi) Figure 4 Figure S and Figure 6 Figure 8

Claims (1)

[Claims] A first external lead member having a substantially L-shaped bent part is attached to the anode lead of a capacitor element made of a metal member having a valve action and an anode lead is led out from the metal member, and the bent part 4 is connected to the lead-out part. ° Connecting the second external lead member so as to intersect with each other and connecting the second external lead member to the electrode lead-out layer of the capacitor element so as to extend in substantially the same direction as the first external lead member to form a capacitor structure; , the capacitor structure is immersed in a water-repellent member such that the immersion level is above the bent portion of the first external lead member. A process of forming a water-repellent coating on a desired portion of the second external lead member, and placing the heated capacitor structure in a resin powder having a substantially flat floating surface so that the vicinity of the bent portion of the first external lead member is at an immersion level. A step of forming a first coating layer by dipping the capacitor structure in a high viscosity resin material having thixotropic properties so that the first coating layer is completely immersed. A method for packaging a solid electrolytic capacitor, the method comprising: forming a second coating layer.