JPS5930529Y2 - tantalum electrolytic capacitor - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a tantalum electrolytic capacitor, and aims to prevent the element itself from burning due to heat generated when a large current flows through the capacitor element for some reason.

Conventionally, tantalum electrolytic capacitors are made by implanting an anode lead wire into tantalum powder, forming and sintering it, and forming an oxide film.

After the semiconductor layer and the cathode layer are formed, an external lead wire that can be soldered is connected to the anode lead wire and the cathode layer by welding or the like.

However, during operation of the capacitor, for example, the oxide film of the capacitor element may be destroyed or short-circuited, causing a large current to flow and causing the capacitor element to generate heat and burn.

For this reason, a temperature fuse or current fuse inserted between the anode lead wire or cathode lead wire and the external lead wire is used, but the temperature fuse will not be cut unless current flows through the element and generates heat. The burning of the capacitor element cannot be prevented unless the current fuse is rated to blow at a low current (approximately 2A or less), and the outer diameter of such a current fuse is very thin, making it difficult to attach it to the leader wire or external lead wire. (For example, due to welding work and melt scattering during welding), and when embedding the fuse in exterior resin or sealing resin, it may be easy to break due to expansion or contraction of the resin. It had drawbacks.

In view of the above points, this invention prevents burning of the capacitor and contamination of attached equipment by promptly interrupting the circuit when a large current flows through the capacitor element in a tantalum electrolytic capacitor. It is.

The present invention will be explained in detail below. As shown in FIG. 1, a capacitor element 1 made of sintered tantalum powder and formed up to the negative plate layer by ordinary means is housed in a metal case 2, and the capacitor element 1 and metal case 2 are bonded together with solder 3. conduction.

An anode lead wire 4 such as a tantalum wire is embedded in the capacitor element 1, but since the anode lead wire 4 is made of a material that cannot be soldered, an anode external lead wire 5 such as nickel is connected to a stainless steel wire. 6.

The connection between the anode lead wire 4 and the stainless steel wire 6 and the external lead wire 5 is usually performed by welding or the like.

Then, the opening of the metal case 2 is filled with a resin 7 for use in Japan.

A cathode external lead wire 8 is connected to the outer bottom surface of the metal case 2 by welding or the like.

As mentioned above, the present invention is constructed by connecting the stainless steel wire 6 between the anode lead wire 4 and the anode external lead wire 5, and has greater mechanical strength than a current fuse or the like. Due to the effects of cutting due to expansion and contraction of the resin.<<
Moreover, even in welding with the anode lead wire 4 and the anode external lead wire 5, there is no crushing, melting and scattering, and the work can be easily performed using a conventional welding machine.

Even if stainless steel wire is selected that can be fused at a current value below that at which the capacitor element ignites or burns, the mechanical strength and workability described above can be maintained, and crushing, melting, and scattering will not occur. It has features that it doesn't have.

According to the inventor's experiments, a tantalum electrolytic capacitor with a rating of 16V-33μF was dielectrically broken, and a voltage of 0°5A to 0.
．． As a result of passing current in 5A increments for 5 minutes each, there is no ignition up to 2A, but 5% at 2.5A and 13% at 3A will ignite and burn, and a capacitor with a rating of 35V and 22μF will not ignite up to 2A. 11% at 2.5 A, 3
In A, 18% ignited and burned.

In addition, in this experiment, we described the case where each current was passed for 5 minutes, but for the currents of 1, 5 A, and 2 A that did not cause ignition, the current was continued to flow for 15 minutes.
The fire continued for up to a minute, but nothing ignited.

In addition, in the above experiment, when the rating was 16V-33μF, it was 2.5A.
The 5% that ignited at 3A took 4 minutes 20 seconds to 4 minutes 45 seconds, and the 13% that ignited at 3A took 3 minutes 53 seconds to 4 minutes 15 seconds. In this case, 11% of the fires that were fired at 2.5A were fired between 4 minutes 17 seconds and 4 minutes 54 seconds, and 18% of the fires that were fired at 3A were fired between 3 minutes and 51 seconds and 4 minutes and 10 seconds.

From the results of this experiment, it was confirmed that the tantalum electrolytic capacitor would not ignite and burn even if a current of 2 A was passed for 5 minutes in a dielectrically broken state.

As another experimental result, as shown in Figure 2, two 0
．． When a stainless steel wire 16 is welded and connected between 5φmm nickel wires and covered with resin 17, when the outer diameter and current value of the stainless steel wire are changed, the time it takes for the stainless steel wire to melt is the first. It was as shown in the table.

In addition, the type of stainless steel wire used was 5US303-Wl.

From the above two experimental results, if you use a tantalum electrolytic capacitor that connects the anode lead wire and the anode external lead wire through a stainless steel wire of 0.16φmm or less, the capacitor element will not be destroyed due to dielectric breakdown. It is safe because it will not ignite or burn if the current flows up to 2A, and even if a current of 2.5A or more flows, it will take less time than the capacitor element to ignite and burn (minimum 3 minutes 51 seconds). Since the stainless steel wire melts in a short time (14 seconds at 2.5 A in Table 1), ignition and combustion of the capacitor element can be prevented.

In the embodiment, a stainless steel wire is connected to the anode lead wire of the capacitor, but when the lead wire terminals are in the same direction as shown in FIG. The cathode lead wire 38 and the cathode external lead wire 39 are connected via the stainless steel wire 36 in the case where the lead wire terminal is in the opposite direction as shown in FIG. A similar effect can be obtained by connecting a stainless steel wire.

Further, in the embodiment, the stainless steel wire connection portions are all coated with resin, but this is not necessarily limited to, for example, insulating plates may be fixedly disposed above and below the connection portions.

As described above, according to the present invention, by connecting a stainless steel wire between the anode lead wire or cathode lead wire of a tantalum electrolytic capacitor and the external lead wire, the circuit can be immediately interrupted when a large current flows. In addition, the stainless wire installation work is significantly more efficient than conventional current fuses and temperature fuses, and the stainless steel wire embedded in the resin prevents the expansion of the resin. , it is possible to provide a tantalum electrolytic capacitor that has excellent characteristics such as being difficult to break even when it shrinks.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the tantalum electrolytic capacitor of the invention, Fig. 2 is a sectional view showing the stainless steel wire connection part of the invention, and Fig. 3 is a sectional view of the tantalum electrolytic capacitor with the lead wire terminals of the invention in the same direction. FIG. 4 is a cross-sectional view showing an example of a tantalum electrolytic capacitor of the present invention having opposite lead wire terminals. 1...Container element, 2...Metal case, 3...Solder, 4...Anode lead wire, 5...Anode external lead Line, 6...
・Stainless steel wire, 7... Resin for sealing.

Claims (1)

[Scope of utility model registration request] In a tantalum electrolytic capacitor in which an external lead wire is connected to an anode lead wire and a cathode lead wire connected to a tantalum electrolytic capacitor element, the anode lead wire or the cathode lead wire is connected to the anode lead wire or the cathode lead wire through a stainless steel wire with an outer diameter of 0.16 mmφ or less. A tantalum electrolytic capacitor characterized by having an external lead wire connected to it.