JP5274230B2 - Manufacturing method of solid electrolytic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress damage to a capacitor element due to heat while maintaining the strength of a thermosetting resin used for an exterior and aging effect, and to shorten the manufacturing time of a solid electrolytic capacitor. <P>SOLUTION: An aging process serves also as a curing accelerating process. Namely, the minus electrode of a voltage application device for aging is connected to a conductive frame 2, and the plus electrode of the voltage application device for aging is connected to a conductive terminal 21 connected to the capacitor element 51 respectively to apply a voltage in a high-temperature atmosphere. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a solid electrolytic capacitor, and more particularly to a method for manufacturing a solid electrolytic capacitor suitable for cost reduction.

  As a method of manufacturing a capacitor having a capacitor element portion covered with resin, a capacitor element electrically connected to a conductive frame is sandwiched between upper and lower molds, and a resin is interposed between the mold and the capacitor element. A method of resin-molding a capacitor element portion by introducing a capacitor is widely used (for example, Patent Document 1). At this time, when a thermosetting resin is used as the resin to be molded, a thermosetting acceleration step for accelerating the curing of the thermosetting resin is required. Moreover, when manufacturing a solid electrolytic capacitor, the aging process for suppressing a leakage current is needed. Hereinafter, a general manufacturing method will be described with reference to FIGS.

  As shown in FIGS. 12A and 12B, the lower mold 101 has an element hole 111 for disposing the capacitor element, a resin pot 113 for holding a resin for molding the capacitor element, and a resin pot 113. A resin introduction path 114 that is a concave groove that communicates with the element hole 111 is provided. Here, the element hole 111 is a rectangular non-through hole larger than the capacitor element disposed inside. As shown in FIG. 13, a conductive frame 102 and a tablet-like heat-soluble resin 103 are installed on the lower mold 101. The lower mold 101 is provided with a plunger 101P for pressing the resin 103 against the upper mold 106. A capacitor element 151 is electrically connected to the conductive frame 102.

  Next, the lower mold 101 is pressed against the heated upper mold 106 from below in the vertical direction. As shown in FIG. 14, the upper mold 106 is provided with an element hole 161 in which a capacitor element is disposed and a resin pot 163. Here, the element hole 161 is a rectangular non-through hole larger than the capacitor element disposed inside. After the upper mold 106 is placed on the lower mold 101, the plunger 101P is pushed toward the upper mold 106 to a predetermined position, whereby the resin 103 is pressurized and melted. The molten resin 103 is introduced into the element hole 111 and the element hole 161 through the resin introduction path 114, and the capacitor element is resin-molded.

  When a thermosetting resin is used as the resin 103, the capacitor element 151 is cured in a resin-molded state by the heating. When the resin 103 is cured, the capacitor element is covered with the resin 103. Subsequently, the packaged capacitor element and conductive frame 102 are taken out of the mold. Further, from the resin 103 cured from the conductive frame 102, the unnecessary resin remaining in the resin pot 163 and cured and the unnecessary resin remaining in the resin introduction path 114 and cured are removed.

  Next, the conductive frame 102 from which the unnecessary resin has been removed is processed by a curing acceleration step of heating at 170 ° C. for several hours. By such treatment, curing of the thermosetting resin is promoted and necessary strength as a capacitor can be obtained.

  Thereafter, as shown in FIG. 15, the conductive terminal 121 on the positive electrode side is cut off from the conductive frame 102. More specifically, the conductive terminal 121 electrically connected to the positive electrode of the capacitor element 151 is disconnected from the conductive frame 102. In this state, as shown in FIG. 16, the negative pole of the voltage marking device is connected to the conductive frame 102, and the positive pole of the voltage loading device is connected to the conductive terminal 121 connected to the capacitor element 151. In this state, the conductive frame 102 is placed in an atmosphere of 150 ° C. and voltage is applied for 2 hours or more. While the leakage current is reduced by such an aging process, since a large current flows in a capacitor element in which a short circuit has already occurred, it can be easily extracted as a defective product.

After this process, the conductive terminal 122 electrically connected to the negative electrode of the capacitor element 151 is separated from the conductive frame 102. Next, a gull-wing type capacitor having the capacitor element 151 is manufactured by bending the conductive terminal 121 and the conductive terminal 122 upward.
JP 2006-108192 A

  By the way, in the said manufacturing method, heating is performed in a hardening acceleration | stimulation process and an aging process. However, there are concerns about adverse effects on the capacitor element due to heating, and in particular, it is considered that the dielectric oxide film is damaged. Therefore, minimizing damage caused by heating has been a problem.

  Further, both the curing acceleration step and the aging step are time-consuming steps, and it has been desired to shorten the steps. However, it has been difficult to simply shorten the time for sufficiently curing the thermosetting resin and the time for increasing the aging effect.

  The present invention has been made in view of such circumstances, and while maintaining the strength and aging effect of the thermosetting resin used for the exterior, it suppresses damage to the capacitor element due to heat and shortens the manufacturing time of the capacitor. With the goal.

  A method for producing a solid electrolytic capacitor according to the present invention includes an anode body made of a valve metal having a dielectric oxide film formed on a surface thereof, and a cathode layer made of a conductive polymer formed on the dielectric oxide film. In order to reduce leakage current, an exterior process for sheathing the capacitor element with a thermosetting resin, a curing acceleration process for heating the capacitor element that has been sheathed to accelerate curing of the exterior, And an aging step of heating and applying voltage to the capacitor element. The aging process also serves as the curing acceleration process.

  According to the said structure, since an aging process serves as a hardening acceleration | stimulation process, it becomes possible to reduce the heating process which requires time 1 process, and working time is shortened. Therefore, it is possible to reduce the cost. In addition, since the number of times of heating can be reduced, an increase in leakage current due to deterioration of the dielectric oxide film can be suppressed as compared with the conventional case. Further, since the aging process also serves as the curing accelerating process, voltage application having an action of suppressing a leakage current is performed at the same time during heating. Therefore, an increase in leakage current due to heating can be further suppressed as compared with the conventional case where two heating steps of an aging step and a curing acceleration step are separately provided.

In the method of manufacturing a solid electrolytic capacitor according to the present invention, it is preferable that the voltage load is started prior to the heating in the aging step.
According to the above configuration, since the voltage load having a leakage current suppressing action is started prior to heating, an increase in leakage current due to heating can be suppressed in advance.

The method for producing a solid electrolytic capacitor according to the present invention is preferably characterized in that, in the aging step, the heating is finished before the voltage application is finished.
According to the above configuration, the heating that increases the leakage current is terminated prior to the completion of voltage loading that has the effect of suppressing leakage current, so that the leakage current is prevented from increasing due to heating or residual heat after the voltage loading is terminated. It becomes possible to do.

  ADVANTAGE OF THE INVENTION According to this invention, while maintaining the intensity | strength and aging effect of the thermosetting resin used for an exterior, while suppressing the damage to the capacitor | condenser element by heat, the manufacturing time of a capacitor | condenser can be shortened.

  Hereinafter, an embodiment of a method for producing a solid electrolytic capacitor embodying the present invention will be described with reference to FIGS. In this manufacturing method, a capacitor element electrically connected to a conductive frame is sandwiched between upper and lower molds, and a resin is introduced between the mold and the capacitor element to resin the capacitor element portion. This is an improvement of the method for producing a solid electrolytic capacitor in which a capacitor element portion to be molded is packaged with a resin.

  As shown in FIGS. 1A and 1B, the lower mold 1 is provided with an element hole 11 in which a capacitor element is disposed and a resin pot 13 for holding resin. A plunger 1 </ b> P for pressing the resin disposed in the resin pot 13 against the upper mold 6 is provided below the resin pot 13. Further, a resin introduction path 14 that connects the resin pot 13 and the element hole 11 is provided, and is used to introduce the resin in the resin pot 13 into the element hole.

  Here, the element hole 11 is a rectangular non-through hole larger than the capacitor element disposed inside. The resin pot 13 is a circular non-through hole. Further, the resin introduction path 14 is a concave groove extending from the resin pot 13, and the depth of the groove decreases in the vicinity of the element hole 11 through a branch to form a resin introduction port 14 a.

  Further, since the same number (four) of resin introduction paths 14 are connected to the plurality of resin pots 13 provided in the lower mold 1, when the same pressure is applied to the resin held in the resin pot 13. The pressure applied to the resin introduction path 14 can be made uniform.

  On the lower mold 1, as shown in FIGS. 2A and 2B, a conductive frame 2 and a tablet-like heat-soluble resin 3 are installed. Here, a capacitor element is electrically connected to the conductive frame 2. More specifically, the positive electrode of the capacitor element 51 is connected to the conductive terminal 21 formed in the conductive frame 2, and the negative electrode of the capacitor element 51 is connected to the conductive terminal 22. The capacitor element includes an anode body made of a valve metal having a dielectric oxide film formed on the surface thereof, and a cathode layer made of a conductive polymer formed on the dielectric oxide film. An anode lead member planted on the anode body is attached to the dielectric frame by welding or the like. The conductive frame is installed so that the capacitor element 51 is disposed in the element hole 11. Resin 3 is placed on resin pot 13.

  Further, as shown in FIGS. 3A and 3B, the lower mold 1 is pressed against the heated upper mold 6 from below in the vertical direction. The upper mold 6 is provided with an element hole 61 in which the capacitor element 51 is disposed. The element hole 61 is a rectangular non-through hole that is larger than the capacitor element 51 disposed inside.

  After the upper mold 6 is placed on the lower mold 1, the plunger 1P is pushed toward the upper mold 6 to a predetermined position, whereby the resin 3 is pressurized and melted. The molten resin 3 is introduced into the element hole 11 and the element hole 61 through the resin introduction path 14, and the capacitor element 51 is resin-molded.

  Since the resin 3 is a thermosetting resin, the capacitor element 51 is cured in a resin-molded state by the heating. When the resin 3 is cured, the capacitor element 51 is covered with the resin 3. Following the exterior process, the exterior capacitor element 51 and conductive frame 2 are removed from the mold. As shown in FIG. 4, the capacitor element 51 and the conductive frame 2 taken out of the cured resin 3 remain in the resin pot 13 and remain in the resin introduction path 14. Hardened unnecessary resin is attached.

  Next, the above-mentioned unnecessary resin is removed by a scraping method. Specifically, unnecessary resin is removed by applying pressure from above to the position indicated by arrows f1 and f2 in FIGS. More specifically, by applying pressure to f1 and f2, unnecessary resin remaining in the resin pot 13 and cured and unnecessary resin remaining in the resin introduction path 14 and cured are removed downward. Such a drop-off method can be performed in one step by using a pin or the like.

  As shown in FIGS. 7 and 8, a capacitor element 51 covered with a resin 3 is electrically connected to the conductive frame 2 from which unnecessary resin is removed. Next, as shown in FIG. 9, the conductive terminal on the positive electrode side is separated from the conductive frame 2. More specifically, the conductive terminal 21 electrically connected to the positive electrode of the capacitor element 51 is separated from the conductive frame 2.

  In the method for manufacturing a solid electrolytic capacitor according to the present embodiment, the aging process also serves as a curing acceleration process in the following processes. That is, as shown in FIG. 10, the negative pole of the aging voltage loading device is connected to the conductive frame 2, and the positive pole of the aging voltage loading device is connected to the conductive terminal 21 connected to the capacitor element 51. Apply voltage under high temperature atmosphere.

  Since this process serves as both a curing acceleration process and an aging process, it satisfies the requirements of both processes. For example, the temperature and the heating time require conditions that can accelerate the curing of the thermosetting resin, and are usually about 170 ° C. and about 2 hours. Moreover, about the loading current, the conditions which exhibit the suppression effect of a leakage current are required, for example, the voltage more than a rating is loaded and an electric current is sent. At this time, for example, a 1.2 mA constant current diode is arranged in series so that an excessive current does not flow.

  In order to suppress damage due to heating, voltage application to the capacitor element 51 is started prior to heating. This makes it possible to suppress an increase in leakage current due to heating.

  Further, in order to suppress damage due to residual heat at the end of the aging process, the end of heating is performed prior to the end of voltage application to the capacitor element 51. Even when the heating is finished, the temperature of the capacitor element 51 does not drop immediately. Even during this period, the dielectric oxide film of the capacitor element 51 continues to be damaged, causing an increase in leakage current. Therefore, the increase in the leakage current due to the residual heat is suppressed by causing the end of heating to precede the end of voltage application to the capacitor element 51.

  The effect of suppressing the leakage current by the aging process has some unclear points, but is considered to be based on the following principle. It is considered that the dielectric oxide film of the capacitor element 51 has fine defects. When the conductive polymer enters the defect, a fine short circuit occurs, and a leakage current is generated when a voltage is applied. Since the leakage current flows through the fine short-circuited portion formed of the conductive polymer by the above aging process, a high load is applied to the conductive polymer in the short-circuited portion and the short-circuit structure is destroyed, so that insulation is achieved. . In this way, the leakage current can be suppressed by the aging process.

  On the other hand, for the capacitor element 51 in which the leakage current is too large and the effect of suppressing the leakage current cannot be expected, the aging process has a screening effect for determining that there is a defect. That is, the dielectric oxide film of the capacitor element 51 has a defect to the extent that the suppression effect does not work, and even if a short circuit occurs due to the conductive polymer entering the defect, leakage occurs when a voltage is applied. Electric current is generated. In this case, since the short-circuit portion is large-scale, the leakage current increases, and the dielectric oxide film itself and the capacitor element 51 are destroyed. Therefore, the leakage current further increases, and it becomes possible to easily find a defective capacitor element. In this way, the aging process enables screening to find a capacitor element that cannot suppress the leakage current.

  After the aging process also serving as the curing acceleration process is completed, the conductive terminal 22 electrically connected to the negative electrode of the capacitor element 51 is separated from the conductive frame 2. Thereafter, as shown in FIG. 11, the conductive terminal 21 and the conductive terminal 22 are bent upward, whereby a gull-wing type capacitor having the capacitor element 51 is manufactured.

According to the lens device of the above embodiment, the following effects can be obtained.
(1) In the said embodiment, since an aging process serves as the said hardening acceleration | stimulation process, it becomes possible to reduce the heating process which takes time one process, and working time is shortened. Therefore, the cost can be reduced. In addition, since the number of times of heating can be reduced, an increase in leakage current due to deterioration of the dielectric oxide film can be suppressed as compared with the conventional case. Further, since the aging process also serves as the curing accelerating process, voltage application having an action of suppressing a leakage current is performed at the same time during heating. Therefore, an increase in leakage current due to heating can be further suppressed as compared with the conventional method having a process only for heating.

(2) In the above-described embodiment, voltage load having a leakage current suppressing action is started prior to heating, so that an increase in leakage current due to heating can be suppressed in advance.
(3) In the above embodiment, since the heating for increasing the leakage current is terminated prior to the voltage loading having the leakage current suppressing action, the leakage current increases due to heating or residual heat after the voltage loading is terminated. This can be suppressed.

In addition, you may change this embodiment as follows.
In the above embodiment, in the aging process, the heating for increasing the leakage current is terminated prior to the voltage loading having the leakage current suppressing action, but other configurations may be used. If an increase in leakage current due to residual heating after the aging process is not particularly observed, for example, the processing time can be shortened by ending the voltage application simultaneously with the end of heating.

  In the above-described embodiment, in the aging process, voltage loading having a leakage current suppressing action is started prior to heating, but another configuration may be used. If the influence of heat at the start of heating is not particularly problematic, the processing time can be shortened by starting voltage application simultaneously with the start of heating.

  -In the said embodiment, although 170 degreeC and the heating for about 2 hours are performed, the condition concerned is only an example and another structure may be sufficient. In short, since it is only necessary to accelerate the curing of the thermosetting resin, various conditions corresponding to the types and characteristics of the thermosetting resin to be used can be taken.

  Since the present invention relates to a method for manufacturing a solid electrolytic capacitor, it can be widely used in industry.

BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, (a) is a top view of a lower metal mold | die, (b) is AA sectional drawing of (a). BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, (a) is a top view which shows the state by which the electrically conductive plate and resin were arrange | positioned on a lower metal mold | die, (b) FIG. 2 is a sectional view of (a). BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, (a) is a partially broken top view which shows the state which pressed the upper metal mold | die, (b) is sectional drawing of (a). It is. It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, and is a top view of the electroconductive frame taken out after resin hardening. It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, and is a partially expanded perspective view for demonstrating the method of removing unnecessary resin from a conductive frame. It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, and is a partial cross section figure for demonstrating the method of removing unnecessary resin from a conductive frame. BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, and is a top view which shows the electroconductive frame from which unnecessary resin was removed. BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, and is sectional drawing which shows the electroconductive frame from which unnecessary resin was removed. It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, and is sectional drawing which shows the state from which the electroconductive terminal of the positive electrode side was cut | disconnected from the electroconductive frame. It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, and is sectional drawing which shows the state in which the capacitor | condenser on a conductive frame is aged. BRIEF DESCRIPTION OF THE DRAWINGS It is drawing explaining one Embodiment of the manufacturing method of the solid electrolytic capacitor which concerns on this invention, and is a front view of the manufactured capacitor | condenser. It is drawing explaining the manufacturing method of the conventional solid electrolytic capacitor, (a) is a top view of a lower mold | die, (b) is AA sectional drawing of (a). It is drawing explaining the manufacturing method of the conventional solid electrolytic capacitor, (a) is a top view which shows the state by which the electrically conductive plate and resin were arrange | positioned on a lower metal mold | die, (b) is a cross section of (a). FIG. It is drawing explaining the manufacturing method of the conventional solid electrolytic capacitor, (a) is a top view of an upper metal mold | die, (b) is sectional drawing of (a). It is drawing explaining the manufacturing method of the conventional solid electrolytic capacitor, and is sectional drawing which shows the state by which the electroconductive terminal of the positive electrode side was cut | disconnected from the electroconductive frame. It is drawing explaining the manufacturing method of the conventional solid electrolytic capacitor, and is sectional drawing which shows the state in which the capacitor | condenser on a conductive frame is aged.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Lower die, 1P ... Plunger, 2 ... Conductive frame, 3 ... Resin, 6 ... Upper die, 11 ... Element hole, 12 ... Element hole, 13 ... Resin pot, 14 ... Resin introduction path, 14a ... Resin introduction Mouth, 21 ... conductive terminal, 22 ... conductive terminal, 51 ... capacitor element, 101 ... lower mold, 101P ... plunger, 102 ... conductive frame, 103 ... resin, 106 ... upper mold, 111 ... element hole, 113 ... resin Pot, 114 ... resin introduction path, 121 ... conductive terminal, 122 ... conductive terminal, 151 ... capacitor element, 161 ... element hole, 163 ... resin pot.

Claims (3)

A step of preparing an anode body made of a valve metal having a dielectric oxide film, a plurality of capacitor elements and a cathode layer made of a dielectric oxide film on the formed conductive polymer on the surface,
Preparing a conductive frame having a plurality of first conductive terminals and a plurality of second conductive terminals;
Mounting the plurality of capacitor elements on the conductive frame and connecting a positive electrode of each capacitor element to each first conductive terminal, and connecting a negative electrode of each capacitor element to each second conductive terminal;
An exterior process of exteriorizing the capacitor element with a thermosetting resin;
Separating each first conductive terminal from the conductive frame after the exterior step;
A curing accelerating step of heating the capacitor element that has been packaged to accelerate curing of the package;
And aging process of heating and voltage application pressure on the capacitor element in order to reduce the leakage current, in the method of manufacturing a solid electrolytic capacitor including,
The aging process, as well as serves as the curing accelerator process, a manufacturing method of a solid electrolytic capacitor and applying a voltage between the conductive said conductive frame and each of the first electrical terminals separated from the frame. In the aging step,
The method for producing a solid electrolytic capacitor according to claim 1, characterized in that to start by prior the voltage application addition to the heating. In the aging step,
The method for producing a solid electrolytic capacitor according to claim 1 or 2, characterized in that by the prior termination of the heating to the end of the voltage application pressure.

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