JPH0362914A - Manufacture of solid-state electrolytic capacitor - Google Patents

Abstract

PURPOSE:To make it possible to protect an anode-lead connecting part rigidly without decreasing production capability by applying a washer comprising specified material at the anode-lead guiding part of a capacitor element, heating and fusing the washer, and bringing the washer into close contact with the anode-lead guiding part. CONSTITUTION:A capacitor element 1 comprises the sintered body of metal powder having valve action such as Ta and Nb. An anode lead 2 is uprightly provided at one end part of the capacitor element 1. A washer comprising any of polyether ether ketone, polyether sulfone or thermoplastic polyimide is applied on an anode-lead guiding part of the capacitor element 1. When the capacitor element 1 is formed with, e.g. Ta powder, the surface of the metal is oxidized when high temperature is maintained under normal pressure, and there is risk of burning at a last stage. Therefore, inactive gas such as N2 or Ar is blown, or the washer 5 is heated and fused in the atmosphere of the inactive gas. Thus the washer 5 is brought into close contact with the anode-lead guiding part of the anode lead 2. The heating and fusing can be performed by a series of flowing steps. Thus, the anode-lead connecting part can rigidly be protected without decreasing production capability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for manufacturing a solid electrolytic capacitor, and more specifically, to a means for protecting an anode lead thereof.

[Conventional technology]

FIG. 2(a) shows a typical conventional capacitor element 1 which forms the core of a solid electrolytic capacitor.

That is, this capacitor element 1 is made of, for example, Ta or Nb.
It is made of a sintered body of gold powder having a valve action, and an anode lead 2 is implanted at one end thereof. One end of the anode lead 2 is pressed before sintering, or it is attached after sintering, for example by welding. An oxide film is formed on the surface of the capacitor cord 1 by electrolytic oxidation, and then a semiconductor electrolyte (solid electrolyte) is formed thereon. For example, by repeating impregnation and thermal decomposition of manganese nitrate several times, Mn0zJff is formed as a semiconductor electrolyte, but at this time, a phenomenon occurs in which MnO□ creeps onto the anode lead 2.

In order to prevent this, conventionally, as shown in FIG.
For example, a silicon resin 4 is applied to the lead-out portion of the anode lead 2 as shown in FIG. 2(c).

[Problem to be solved by the invention]

However, in the method shown in No. 211M(b), if the fitting with the anode lead 2 is loose, the resin plate 3 will float up.
However, not only is it not effective in preventing MnO□ from creeping up,
When welding the external lead wire to the anode lead 2, a problem arises. In other words, since the connection between the sintered body and the anode lead is not protected in any way, it is easily affected by mechanical stress when welding the external lead wire to the anode lead 2 or thermal shrinkage stress of the exterior resin, resulting in characteristic deterioration, especially This leads to an increase in leakage current.

On the other hand, when the resin 4 is applied as shown in FIG. There are difficulties in workability.

This invention was made to solve the above-mentioned conventional drawbacks, and the purpose is to provide a solid electrolytic capacitor that can effectively protect the connection between the capacitor element and the anode lead without impairing productivity. The purpose is to provide a manufacturing method.

[Means to solve the problem]

In order to achieve the above [1], in this invention, Ta
Polyether ether ketone (PEI; , polyether sulfone (pi
After a washer made of either ES) or thermoplastic polyimide (T)'1) is heated and melted, the washer is brought into close contact with the anode lead lead-out portion.

When heating and melting a washer with a relatively high melting point among the washers mentioned above, if the capacitor element is made of Ta powder, for example, if the capacitor element is kept at high temperature under normal pressure, the metal surface will oxidize and eventually burn. There is danger.

Therefore, the washer is heated and melted using heated N2
Alternatively, an inert gas such as Ar may be sprayed, but it is preferable to melt the material in the inert gas atmosphere.

In addition, heating and melting of the washer is: 1) performed before forming an oxide film by electrolytic oxidation of the capacitor element, 2) performed after forming an oxide film on the surface of the capacitor element by electrolytic oxidation, and 2) melting the solid electrolyte on the capacitor element. It is preferable to perform this at the same time as forming the solid electrolyte or after forming the solid electrolyte.

The washer material is PEEK (polyetheretherketone; melting point: 340℃)
), P E S (polyether sulfone; no melting point because it is amorphous), 'l' P I (thermoplastic polyimide; melting point 382°C)
, is used.

Here, the method for manufacturing a solid electrolytic capacitor according to the present invention will be described in more detail with reference to No. 1I5i1. First, as shown in Figure (a), a washer 5 made of a film or sheet selected from the above materials was cut into a size suitable for the capacitor element l, and this was attached to the anode lead 2. Thereafter, the anode lead 2 is welded to a suitable hoop material 6. When the washer 5 is transported to the next construction site while attached to the hoop material 6, the washer 5 is placed against the lead-out portion of the anode lead 2 by a guide member (not shown) as shown in FIG. The position i' is determined so that Next, a dryer or the like (not shown) is used to spray, for example, N2 gas at a temperature of about 100 ml. As a result, the washer 5 melts and comes into close contact with the lead-out portion of the anode lead 2, as shown in FIG. 2C.

Reference numeral 5a indicates the one in close contact.

[For production]

Since the above heating and melting can be performed in a series of flow steps, the anode lead connection portion can be strongly protected without reducing production capacity.

(Example ↓) External dimensions 0.94X 1.95X 1. Onw's tantalum capacitor element's anode lead was coated with polyketone film PE top K's 200J (1'l'8 product name;
Made by ICI Japan @) thickness 0.1
A mm washer was inserted through the tube, and the washer was melted while supplying N2 gas using a P1 gun (manufactured by Nikko Metal Co., Ltd.). Next, an oxide film is applied to the surface of the capacitor element by electrolytic oxidation, and Mn0zJtlj, carbon;
After sequentially forming silver layers and connecting external terminals, it is covered with exterior resin (epoxy), and the rated voltage is 4V and the capacitance is 104.
A F solid electrolytic capacitor was manufactured.

(Example 2) A polyketone film) 'HI4K rStaver XK300 was applied to the anode lead of the same capacitor element as in Example 1.
A washer with a thickness of 0.075 nv+ made of J. After heating, the washer was heated in an electric furnace to melt it. After further performing a second chemical formation to form the desired oxide skin, the same <
, MnO, Ji, carbon layers, and silver layers were formed in j terms, external terminals were connected, and then covered with exterior resin (epoxy) to produce a solid electrolytic capacitor with a rated voltage of 4 V and a capacitance of 10 μF.

(Example 3) For the anode lead of the same capacitor element as in Example 1.

A 0.1 mm thick washer made of polyimide film "NEw-TPl" (trade name; manufactured by Mitsui Toatsu ■) was inserted, and a heat gun (manufactured by Nikko Metal Co., Ltd.) was used as in Example 1.
The washer was melted while supplying N2 gas. Next, an oxide film is applied to the surface of the capacitor element by electrolytic oxidation, and an MnO layer, a carbon layer, and a silver layer are sequentially formed. After connecting external terminals, the capacitor element is covered with an exterior resin (epoxy), and the rated voltage is 4V, static A solid electrolytic capacitor with a capacitance of 10μ was manufactured.

[Comparative Example 1] TI”L on the anode lead of the same capacitor element as in Example ↓
: A washer with a thickness of 0.2 mm made of (tetrafluoroethylene) is inserted, electrolytic oxidation is performed to form an oxide film on the surface, and then an MnO2 layer, a carbon layer, and a silver M are sequentially formed, and external terminals are connected. Thereafter, it was covered with an exterior resin (epoxy) to produce a solid electrolytic capacitor with a rated voltage of 4V and a capacitance of 10μ.

(Example 4) An amorphous film "Pi<Sr Stay Bar 5too" (product name:
Made by ICI Japan) thickness 0.1
An oxide film was formed on the surface of the capacitor element by electrolytic oxidation by passing a washer of IIl[11 through the persimmon. Next, it is impregnated with an aqueous solution of manganese nitrate (specific gravity 1.3) and decomposed at a high temperature (300 to 350°C) in a pyrolysis furnace to form MnO.
The washer was melted at the same time as No. 2 was produced. Next, thermal decomposition of manganese nitrate was repeated a predetermined number of times to form MnO and Jσ. After that, carbon nano and silver layers were sequentially formed, external terminals were connected, and the capacitor was covered with exterior resin (epoxy) to produce a solid electrolytic capacitor with a rated voltage of 16 μm and an electrostatic field of 1 to 3.3 μm. .

[Comparative Example 2] Same as Conventional Example 1, the rated voltage was 16V, and the electrostatic field was 3.3V.
We have manufactured a μ-hard solid electrolytic capacitor.

10,000 pieces of each of the above examples and comparative examples were prepared, and their capacitance Cap (μt') and tangent of loss angle tan
δ, leakage current LC (μA), product characteristic defect rate (
%) and MnO□ creep-up rate (%), the results (average values) are shown in the table.

(Table) As is clear from this table, the characteristic defect rate of each example is 1/2 to 1/3 that of the conventional example. Also, Mn
The O□ creep rate is recorded as O$ in each example. Furthermore, in terms of leakage current, a remarkable effect of alleviating stress during welding of the anode external terminal and stress on the exterior resin is observed.

〔Effect of the invention〕

As explained above, according to the present invention, the anode lead lead-out portion of the capacitor element is made of polyetheretherketone (PEEK), polyethersulfone (pies), or thermal 1h-J ffl polyimide (TPI). By inserting a washer and heating and melting the washer so that it adheres closely to the anode lead lead-out part, the anode lead connection part can be strongly protected during a series of flow processes without reducing production capacity. . In addition, since the film used for the washer has a moderate strength, the film thickness should be adjusted, for example, from 0.075 to 0.
．． It is possible to make the film as thin as about 1 mm, so the height of the molten film covered can be small, and furthermore, the cost of the film can be reduced.

[Brief explanation of drawings]

The construction drawings (a) to (c) are explanatory diagrams showing the manufacturing process of the solid electrolytic capacitor according to the present invention, and the drawings (a) to (c) are
are explanatory diagrams showing conventional examples, respectively. In the figure, 1 is a capacitor element, 2 is an anode lead, and 5 is a hoop material washer made of thermoplastic highly heat-resistant resin. Patent application Artificial Lunar Co., Ltd.

Claims (4)

[Claims] (1) Polyetheretherketone (PEEK), Polyether sulfone (
1. A method for manufacturing a solid electrolytic capacitor, which comprises inserting a washer made of either PES or thermoplastic polyimide (TPI), heating and melting the washer and bringing it into close contact with the anode lead lead-out part. (2) The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the washer is heated and melted using a high-temperature inert gas. (3) The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein the heating and melting of the washer is performed after forming an oxide film on the surface of the capacitor element by electrolytic oxidation. (4) The method for manufacturing a solid electrolytic capacitor according to claim 1, wherein heating and melting the washer is performed at the same time as forming the solid electrolyte on the capacitor element or after forming the solid electrolyte.