JP2006049588A - Method for manufacturing solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate false short status furthermore when a solid electrolytic capacitor is manufactured. <P>SOLUTION: A method for manufacturing a solid electrolytic capacitor is provided with a process wherein multiple times impression of current or voltage is performed beforehand to a rolling up element 21, and false short status is eliminated; and a process wherein measuring voltage is impressed to the rolling up element 21, and whether short-circuiting is generated is judged by detected current value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a method for manufacturing a solid electrolytic capacitor.

FIG. 1 is a sectional view of a conventional solid electrolytic capacitor (1), and FIG. 2 is an exploded perspective view of a capacitor element (2) in the solid electrolytic capacitor (1) of FIG. 1 (for example, Patent Document 1). reference).
In this case, the capacitor element (2) is housed in an aluminum case (3) whose one end is open, and the opening of the case (3) is sealed with a rubber sealing member (30). . As shown in FIG. 2, the capacitor element (2) comprises an anode foil (22), which is an aluminum foil having a chemical conversion film, and a cathode foil (23), which is an aluminum foil, and a separator paper (4) that is an insulator. A winding element (21) wound in a roll shape through a solid electrolyte such as TCNQ (7,7,8,8-tetracyanoquinodimethane) complex salt is impregnated inside. Examples of the solid electrolyte include conductive polymers such as polypyrrole, polythiophene, polyfuran, and polyaniline.
A pair of tab terminals (25) and (25) are drawn out from the anode foil (22) and the cathode foil (23), and lead wires (20) and (20) extend from the tab terminals (25) and (25). The lead wires (20) and (20) penetrate the sealing member (30) and protrude outward. The peripheral edge of the opening of the case (3) is curled to hold the sealing member (30).
After winding the anode foil (22) and the cathode foil (23) and before impregnating the winding element (21) with the solid electrolyte, the lead wires (20) and (20) are energized and wound. Check whether the take-off element (21) is short-circuited. Among these, there are semi-defective products that are in a quasi-short state, in addition to good products that are not short-circuited and defective products that are completely short-circuited. This pseudo short state means that although both foils (22) and (23) are accurately wound, chips and metal powder remain on both foils (22) and (23), or This indicates a short-circuited state due to slight misalignment of the tab terminals (25) and (25) and the separator paper (4). It is known that by applying a predetermined level of voltage or current to the pseudo short-winding element (21), the pseudo short-circuit state is eliminated and the product becomes a non-defective product (for example, Patent Documents). 2).

JP-A-6-236831 JP-A-11-145006

Conventionally, a voltage of a predetermined level is applied once to the winding element (21), a current flowing through the winding element (21) is detected, and whether or not a short circuit has occurred is checked. That is, by applying the voltage, a short check is performed and a pseudo short state is not solved.
However, this did not completely eliminate the pseudo short-circuit state, and the winding element (21) that should be a good product was determined to be a defective product. Accordingly, the yield in the manufacturing process of the winding element (21) is poor, and the production efficiency is poor.
An object of the present invention is to further eliminate the pseudo short-circuit state.

The method of manufacturing the solid electrolytic capacitor includes a step of applying a current or voltage to the winding element (21) in advance a plurality of times to eliminate a pseudo short-circuit state,
A step of applying a measurement voltage to the winding element (21) and determining whether or not a short circuit occurs at the detected current value is provided.

  In the present invention, since the current or voltage is applied to the winding element (21) a plurality of times before determining whether the winding element (21) is short-circuited, the pseudo short-circuit state is further eliminated. it can. Therefore, the yield in the manufacturing process of the winding element (21) is improved, and the production efficiency is improved.

Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
As in the prior art, as shown in FIG. 2, the capacitor element (2) of the solid electrolytic capacitor (1) includes an anode foil (22) that is an aluminum foil on which a chemical conversion film is formed, and a cathode foil (23 that is an aluminum foil). ) Is wound in a roll shape through a separator paper (4) as an insulator, and is wound up by a winding tape (26) and is wound up (21).

The solid electrolytic capacitor (1) is formed as follows.
The anode foil (22) and the cathode foil (23) are wound in a roll shape through the separator paper (4) to make a winding element (21). After the cut formation of the winding element (21), carbonization is performed at 200 ° C. or higher. Here, the cut formation is to repair the chemical film damaged when winding the anode foil (22), or to form a chemical film on the end face of the anode foil (22) where the chemical film is not formed again. Refers to chemical conversion treatment.
Thereafter, a mixed solution is prepared by adding a monomer to an oxidant solution obtained by adding an oxidant such as ferric p-toluenesulfonate to an alcohol solvent such as butanol. The winding element (21) is immersed in the mixed solution to form a conductive polymer layer inside the winding element (21). In this way, a capacitor element (2) is obtained.
Thereafter, as shown in FIG. 1, the lead wires (20) and (20) of the capacitor element (2) are fitted into the sealing member (30), and the capacitor element (2) is stored in the case (3). ) And curl it by deep drawing. After inserting the plastic seat plate (31) through the lead wires (20) and (20) from above the sealing member (30), the lead wires (20) and (20) are bent outward, and the seat plate A solid electrolytic capacitor (1) is obtained by contacting with (31).

In the above process, energize the lead wires (20) and (20) between making the winding element (21) and immersing the winding element (21) in the mixed solution. It is checked whether or not the element (21) is short-circuited. In this example, there is a feature in the previous process of this check.
First, a predetermined level of current or voltage is applied to the lead wires 20 and 20 a plurality of times. The current or voltage is applied 10 or more times during 100 msec, and the current or voltage level will be described later. Thereafter, a measurement voltage is applied to the winding element (21), and it is determined whether or not there is a short circuit at the detected current value.
In this example, the current or voltage is applied to the winding element (21) a plurality of times before determining whether the winding element (21) is short-circuited. Can be solved better. Therefore, the yield in the manufacturing process of the winding element (21) is improved, and the production efficiency is improved.

The applicant conducted the following experiment in order to confirm the above effect.
First, a winding element (21) for the capacitor (1) having a rated voltage of 2.5 V and an electrostatic capacity of 180 μF is made. The diameter of the case (3) that houses the winding element (21) is 5.0 mm and the height is 6.0 mm. A voltage of 25 V and a current of 500 mA were intermittently applied 10 times to this winding element (21). The voltage and current are applied in pulses. After 100 msec from the application, a short check was performed by applying a measurement voltage of 25 V and determining that the detected current was 10 mA or more. This is Example 1.
Next, a winding element (21) for the capacitor (1) having a rated voltage of 4 V and an electrostatic capacity of 560 μF is produced. Case (3) has a diameter of 8.0 mm and a height of 11.5 mm. After applying a pulse voltage or current to the winding element (21) in the same manner as in Example 1, a short check is performed, and this is referred to as Example 2.

Next, the applicant makes a winding element (21) for the capacitor (1) having a rated voltage of 2.5 V and a capacitance of 180 μF. The diameter of the case (3) for storing the winding element (21) is 5.0 mm and the height is 6.0 mm, which corresponds to the first embodiment. At the same time that a measuring voltage of 25 V was applied to the winding element (21), a short check was performed based on the judgment standard that the detected current was 10 mA or more. That is, no pulse voltage or current is applied in advance before the short check. This will be referred to as Conventional Example 1.
Next, a winding element (21) for the capacitor (1) having a rated voltage of 4 V and an electrostatic capacity of 560 μF is produced. The diameter of the case (3) is 8.0 mm and the height is 11.5 mm, which corresponds to the second embodiment. As in Conventional Example 1, a short check was performed by applying a measurement voltage of 25 V to the winding element (21). This will be referred to as Conventional Example 2.
The applicant prepared a large number of capacitors (1) of Examples 1 and 2 and Conventional Examples 1 and 2 and obtained a defect rate at the time of short check (hereinafter abbreviated as a short defect rate). The results are shown in FIG.
As can be seen from the results of FIG. 3, the capacitors (1) of Examples 1 and 2 in which a short check was performed after applying a pulse voltage or a current a plurality of times in advance were more than the capacitors (1) of Conventional Examples 1 and 2. The pseudo short-circuit state could be eliminated and the defect rate could be reduced.

  The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. In addition, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.

It is sectional drawing of the conventional solid electrolytic capacitor. It is a disassembled perspective view of the capacitor | condenser element in the solid electrolytic capacitor of FIG. It is a table | surface which shows the result of having calculated | required the short-circuit defect rate of the capacitor | condenser of Example 1, 2 and the prior art examples 1 and 2. FIG.

Explanation of symbols

(1) Solid electrolytic capacitor
(4) Separator paper
(21) Winding element
(22) Anode foil
(23) Cathode foil

Claims (1)

A method for producing a solid electrolytic capacitor comprising a winding element (21) wound with an anode foil (22) and a cathode foil (23),
Applying current or voltage multiple times in advance to the winding element (21) to eliminate the pseudo short-circuit state,
A method for manufacturing a solid electrolytic capacitor comprising a step of applying a measurement voltage to a winding element (21) and determining whether or not a short circuit occurs at a detected current value.

Images