JPH0845794A - Solid-state electrolytic capacitor - Google Patents

Abstract

PURPOSE:To provide a solid-state electrolytic capacitor which prevents fuming and ignition of a capacitor without necessitating independent components like a fuse, and further has quenching function. CONSTITUTION:The solid-state electrolytic capacitor is constituted by covering and encapsulating a capacitor element 8 with encapsulating resin. The encapsulating resin 9, 11 constitutes multilayered structure. A quenching material layer 10 is formed between the encapsulating resin layers 9 and 11. The quenching material layer 10 is constituted of an incombustible material layer or a fire extinguisher layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid electrolytic capacitor, and more particularly to a self-extinguishing exterior structure for a resin-coated solid electrolytic capacitor.

[0002]

2. Description of the Related Art Generally, among solid electrolytic capacitors, solid electrolytic capacitors having polarity, such as solid tantalum electrolytic capacitors, generate an excessive current when a short circuit occurs due to an incorrect connection or a failure, and the solid electrolytic capacitors themselves generate heat and ignite. , The printed circuit board on which the surrounding parts and the solid electrolytic capacitor were mounted was sometimes burned. Therefore, conventionally, in order to prevent the ignition of this solid electrolytic capacitor, the
As disclosed in Japanese Patent No. 168238, a so-called fuse built-in type solid electrolytic capacitor having a structure in which a fuse is connected in series with a capacitor element and the fuse is enclosed in an exterior resin is widely used. However, the solid electrolytic capacitor with a built-in fuse needs to incorporate a separate component called a fuse, which complicates the configuration, and thus has a problem that the size is inevitably increased and the cost is increased. Therefore, as shown in FIG.
In Japanese Patent No. 94410, an outer periphery of a capacitor element 1 made of a sintered body of the same kind of metal, in which an anode lead 6 made of a metal such as tantalum having a valve action is sewn in the center and externally connected to a lead 4 by welding, is formed. An anodized film is formed, a semiconductor layer 2 made of manganese dioxide and a cathode layer 3 made of carbon are sequentially formed on the anodized film, and a binder made of an inorganic material for connecting the external lead 5 to the outer circumference of the cathode layer 3. By providing the non-combustible silver paste 7 having
Techniques for preventing smoke and ignition are disclosed.

[0003]

However, in the solid electrolytic capacitor having the above-mentioned structure, although the fuse is not required to be incorporated, the surface of the anode lead lead-out portion is not covered with the non-combustible silver paste, so that the largest combustible portion is formed. However, there is a problem in that smoke and ignition cannot be completely prevented because the capacitor element as described above cannot be completely covered with an incombustible substance. An object of the present invention is to solve the above problems and to provide a solid electrolytic capacitor which not only prevents smoke and ignition of the capacitor but also has a fire extinguishing function.

[0004]

[Means for Solving the Problems] A solid electrolytic capacitor in which a capacitor element is coated with an exterior resin,
The exterior resin has a multi-layered structure, and a fire-extinguishing substance layer is provided between layers of the exterior resin, wherein the fire-extinguishing substance layer is one of asbestos, glass fiber, fluorine-based resin, and silicone resin, or A non-combustible substance layer composed of two or more substances, or the fire-extinguishing substance layer is sodium silicate, anodized alum, ammonium chloride, urea, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, ammonium sulfate, phosphorus. Ammonium dihydrogen acid or TMB
It is desirable that the fire extinguishing agent layer is made of one or more of the above substances.

[0005]

With the above structure, since the fire extinguishing substance layer is provided between the multilayer exterior resin layers of the solid electrolytic capacitor,
The solid electrolytic capacitor is short-circuited due to incorrect connection or failure,
Even if the solid electrolytic capacitor itself heats up and ignites due to excessive current, the non-combustible substance layer or fire extinguishing agent layer provided between the exterior resin layers surrounding the entire circumference of the capacitor element prevents the solid electrolytic capacitor from igniting. At the same time, it has a fire extinguishing function to prevent the spread of fire to the surrounding area. Further, a separate component such as a built-in fuse is not needed, and it is possible to prevent an increase in size and cost.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. The same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. The solid electrolytic capacitor according to the present invention is formed as described below. That is, as shown in FIG. 1, similarly to the conventional example, the outer periphery of the capacitor element 1 made of a sintered body of the same metal in which a metal anode lead 6 having a valve action such as tantalum is erected in the central portion is formed. To form an anodized film, a semiconductor layer made of manganese dioxide and a cathode layer (not shown) made of carbon are sequentially formed on the anodized film, and external leads 4 and 5 are connected to the anode lead 6 and the cathode layer, respectively. To form the capacitor element 8. Then, the outer periphery of the capacitor element 8 is covered with an exterior resin made of epoxy resin to form the first layer 9. Then, the second layer 10 is formed by coating with a fire-extinguishing substance layer made of sodium carbonate and ammonium chloride, and further coated by an exterior resin made of epoxy resin to form a third layer 11, which is completed. In the solid electrolytic capacitor thus formed, when an overcurrent flows due to reverse connection or short circuit between the electrodes and the capacitor element 8 generates heat and ignites, sodium carbonate in the extinguishing substance layer is generated by decomposition of ammonium chloride. Since it combines with hydrochloric acid to produce salt, water and carbon dioxide, the produced water serves as cooling water, and the carbon dioxide extinguishes fire by blocking the supply of oxygen to the ignition part.

The outer resin layer of the first layer 9 has a function of preventing the fire-extinguishing substance from directly contacting the capacitor body to cause insulation deterioration, and the outer resin layer of the third layer 11 is extinguishable. It has a function of holding the material layer and preventing evaporation and scattering to the outside. As shown in FIG. 2, a solid electrolytic capacitor according to another embodiment of the present invention includes a first layer 9, a third layer 11 and a fifth layer.
The layer 13 is an exterior resin layer made of the same epoxy resin as in the above embodiment, the second layer 12 is a non-combustible substance layer made of glass fiber, and the fourth layer 14 is a fire-extinguishing substance layer made of sodium carbonate and ammonium chloride. Has been done. According to this example,
The small ignition is extinguished by being blocked from the outside air by the glass fiber of the second layer 12, and the large ignition is extinguished by the extinguishing agent layer of the fourth layer 14 in the same manner as in the above embodiment. The example in which the exterior resin layers are two and three layers, and the non-combustible substance layer made of glass fiber and the extinguishing agent layer made of sodium carbonate and ammonium chloride are used as the extinguishing substance layer have been described above. Are not limited to these examples, and one or a mixture of at least one of asbestos, fluorine resin, and silicone resin may be used as the constituent material of the noncombustible substance layer, or sodium silicate may be used as the constituent material of the extinguishing agent layer. , Burnt alum, urea, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate,
Ammonium sulfate, ammonium dihydrogen phosphate or TM
Even if one or more mixtures of any one of B are used and further layers are formed, an effect equivalent to or more than the above example can be obtained.

[0008]

According to the present invention, since the fire-extinguishing substance layer is provided between the multilayer exterior resin layers of the solid electrolytic capacitor, the solid electrolytic capacitor is short-circuited due to incorrect connection or failure, and an excessive current is generated. The solid electrolytic capacitor itself generates heat,
Even if it ignites, the non-combustible substance layer or fire extinguishing agent layer provided between the exterior resin layers surrounding the entire circumference of the capacitor element,
The solid electrolytic capacitor prevents ignition and has a fire extinguishing function. Further, a separate component such as a built-in fuse becomes unnecessary, and it is possible to prevent the solid electrolytic capacitor from becoming large and expensive.

[Brief description of drawings]

FIG. 1 is a sectional view of a solid electrolytic capacitor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a solid electrolytic capacitor according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a conventional solid electrolytic capacitor

[Explanation of symbols]

 8 Capacitor Element 9 First Layer 10, 12 Second Layer 11 Third Layer 13 Fifth Layer 14 Fourth Layer

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Claims (3)

[Claims] 1. A solid electrolytic capacitor in which a capacitor element is coated with an exterior resin, and the exterior resin has a multilayer structure, and a fire-extinguishing substance layer is provided between layers of the exterior resin. 2. The fire-extinguishing substance layer is a non-flammable substance layer made of one or more substances selected from asbestos, glass fiber, fluorine resin and silicone resin. Solid electrolytic capacitor. 3. The fire-extinguishing substance layer comprises sodium silicate, an alum, ammonium chloride, urea, sodium carbonate, sodium hydrogen carbonate, potassium carbonate, potassium hydrogen carbonate, ammonium sulfate, ammonium dihydrogen phosphate or TMB.
The solid electrolytic capacitor according to claim 1, which is a fire extinguishing agent layer made of one or more substances of (trimethoxyboroxine).