JPH088149A - Electrolytic capacitor and manufacturing method - Google Patents

Abstract

PURPOSE:To make it possible to estimate a life of an electrolytic capacitor easily and surely by making the inside of a storage case visible from outside for confirmation. CONSTITUTION:In an electrolytic capacitor, a capacitor element impregnated with electrolytic solution is stored in a tightly sealed state in a storage case (A) made of a transparent resin case 5 joined with a metallic case 6. The metallic case 6 has a ring-shaped fitting groove on one opening end, while the resin case 5 with a bottom has a projected part 10 near the opened end with the same diameter as the inside diameter of the metallic case 6. After a rubber ring is fitted to the lower face of the projected part, the lower end of the metallic case is pressed so that the projected part is pushed to the fitting groove of the metallic case 6. Since the resin case 5 is transparent, the capacitor element in the storage case can be visually observed from outside. In addition, the storage case is tightly sealed in a sealed-state fixing step and a deterioration caused by outside air of the capacitor element can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic capacitor whose life can be easily predicted by visually confirming deterioration over time due to use, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, electronic parts have been required to have smaller size, higher performance and improved reliability. The same applies to the electrolytic capacitor incorporated in the device and used.

Generally, in an electrolytic capacitor, a pair of lead terminals also made of aluminum are connected to a pair of anode foil and cathode foil made of high-purity aluminum foil, and a capacitor paper is provided between the pair of anode foil and cathode foil. It uses a capacitor element formed by interposing. The surface of this capacitor element is electrochemically roughened in order to increase the surface area of the aluminum anode foil / cathode foil. Furthermore, a dielectric oxide film is formed on the anode foil.

As an electrolytic capacitor using such a capacitor element, there is, for example, one shown in FIG. That is, the capacitor element 21 is housed in the housing case 25 made of a cylindrical metal that is impregnated with the driving electrolytic solution and has an opening on one side. The sealing plate 23, which is a sealing member for the opening of the housing case 25, is provided with a rivet portion 24. The lead-out terminal 22 of the capacitor element 21 is connected to the rivet portion 24 of the sealing plate 23, and the sealing plate 23 is bite into the opening of the housing case 25 to seal it. In the electrolytic capacitor configured as described above, by sealing the housing case 25, the capacitor element 2 is shielded from the outside air to be protected from moisture.
1 and the driving electrolyte are prevented from deteriorating.

[0005]

However, the conventional electrolytic capacitor has the following problems.
That is, it is known that the electrolytic capacitor deteriorates with time due to use. As the deterioration with time, along with the deterioration of the dielectric oxide film on the surface of the anode foil and the deterioration of the driving electrolyte,
Hydrogen gas is generated from the capacitor element. With such deterioration over time, the characteristics (electrostatic capacity, loss, leakage current) of the electrolytic capacitor also change over time. This generally means that the capacitance decreases as the usage time increases, resulting in increased loss and leakage current.

Such deterioration with time is inevitable for electrolytic capacitors. This is not only the deterioration of the capacitor characteristics. For example, when the equipment used is at a high temperature, the electrolytic solution evaporates and thermally decomposes as one of the deteriorations of the driving electrolytic solution. When the evaporated and pyrolyzed product is cooled, it may become a liquid containing an alkali component having a high hydrogen ion concentration, depending on the constituent components of the driving electrolytic solution.
It has been confirmed that when such a liquid adheres to the lead terminal and a voltage is applied to the capacitor in this state, an erosion reaction occurs on the anode side. If the lead-out terminal corrodes in this way, if the lead-out terminal is used without being noticed, the corrosion will progress further, and eventually the lead-out terminal will be disconnected and the function of the capacitor will be lost.

In recognition of such a decrease in the reliability of the capacitor, in a device in which the capacitor is incorporated and used, the function of the device is not lost due to the decrease in the reliability of the capacitor. It corresponds to. That is, the life of an electrolytic capacitor that is actually used by incorporating it into a device is calculated by a complex calculation from Arrhenius' law (10 ° C, double rule), and estimated according to the guaranteed life of the electrolytic capacitor as a product. are doing. Then, the capacitor is replaced based on the estimated life.

With respect to deterioration over time due to the use of electrolytic capacitors, it is known that the deterioration of the driving electrolyte causes the capacitor elements to turn brown over time. Therefore, the internal state of the electrolytic capacitor in use,
That is, it is possible to easily determine the deterioration state of the electrolytic capacitor by examining the degree of color change of the capacitor element. However, in the conventional electrolytic capacitor, since the capacitor element is hermetically housed in the housing case made of opaque metal, it is difficult to confirm the degree of color change of the capacitor element from the outside of the case. Therefore, it is impossible to easily determine the life of the electrolytic capacitor by examining the degree of color change of the capacitor element.

The present invention has been proposed in order to solve such a problem, and a first object thereof is to confirm the state of the capacitor element housed in the case from the outside of the case.
It is an object of the present invention to provide an electrolytic capacitor which can easily and accurately predict the life of the electrolytic capacitor by making it distinguishable. A second object is to provide an electrolytic capacitor capable of confirming / distinguishing the inside of the case from the outside and forming a small housing case by connecting the resin case and the metal case by closely fixing. Is. A third object is to provide an electrolytic capacitor that can make the connection between the resin case and the metal case in a highly airtight state. A fourth object is to provide an electrolytic capacitor capable of maintaining a highly airtight connection between a resin case and a metal case. A fifth object is to provide a method for manufacturing an electrolytic capacitor whose life can be easily grasped.

[0010]

In order to solve the above-mentioned problems, according to the present invention, a capacitor element is formed by winding an anode foil made of a valve metal and a cathode foil with a spacer interposed therebetween. In the electrolytic capacitor in which the capacitor element is impregnated with the driving electrolytic solution and hermetically accommodated in the housing case, the housing case includes a metal case and a transparent resin case, and the inner peripheral surface of the metal case and the The resin case is characterized in that it is tightly fixed and connected to the end portion of the resin case.

According to the second aspect of the present invention, the resin case according to the first aspect is formed in a cylindrical shape with one end serving as a bottom surface and the other end opening to the outer peripheral edge of the opened end. Is provided with a ring-shaped projecting portion projecting outward and having the same diameter as the inner circumference of the metal case, and the metal case is formed in a cylindrical shape with both ends open, Positioning means for locking the protruding portion of the resin case is formed on the peripheral surface of the opening so as to protrude inward in a ring shape.

According to a third aspect of the present invention, the protrusion of the resin case according to the second aspect is pressed in the direction of the positioning means of the metal case by the pressing means.

According to a fourth aspect of the invention, the pressing means according to the third aspect is characterized in that an elastic member is provided or a pressing portion is formed at the tip of the metal case.

In a fifth aspect of the invention, a capacitor element is formed by winding a spacer between an anode foil and a cathode foil made of a valve metal to form a capacitor element, and the capacitor element is impregnated with a driving electrolytic solution to be housed. In a method of manufacturing an electrolytic capacitor that is hermetically housed in a case, a cylindrical metal case having both ends open has positioning means projecting inwardly in a ring shape, and has a bottom surface at one end. A cylindrical transparent resin case with the other end opened, and provided with a ring-shaped projection that projects outward in the opened outer edge and has a peripheral surface having the same diameter as the inner circumference of the metal case, In one opening of the metal case, the opening side end of the resin case is inserted until the protrusion contacts the positioning means, and the protrusion is pressed by the pressing means in the direction of the positioning means, Resin case And and forming a housing case in close contact fixing the metal case.

[0015]

The operation of the present invention having the above construction is as follows. That is, according to the first aspect of the invention, since the transparent resin is used for the case that houses the capacitor element, the inside can be visually confirmed. This makes it possible to predict the life of the electrolytic capacitor from the change with time of discoloration due to deterioration of the capacitor element.

According to the second aspect of the present invention, the housing case is made of a transparent resin case on the bottom surface side and the metal case on the one opening side. The both cases are closely fixed, so that they are connected in a highly airtight state. As a result, it is possible to easily form a highly airtight accommodating case in which the life of the electrolytic capacitor can be visually predicted.

According to the third aspect of the invention, the resin case is securely fixed inside the metal case by the positioning means and the pressing means, so that the housing case can maintain a highly airtight connection state.

According to the fourth aspect of the present invention, since the protruding portion of the resin case is pressed in the direction of the positioning means by the elastic member or the pressing portion on the tip of the metal case, the resin case can be securely fixed and the housing case can be fixed. Improves air tightness.

According to the fifth aspect of the present invention, by closely fixing the transparent resin case and the metal case, the inside of the case can be visually confirmed, and a highly airtight accommodating case can be obtained. From the change, it is possible to manufacture an electrolytic capacitor that makes it possible to predict the life of the electrolytic capacitor.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the electrolytic capacitor according to the present invention will be specifically described below with reference to FIGS. Here, FIG. 1 is a front sectional view showing an example of an electrolytic capacitor according to the present embodiment, and FIG. 2 is a front sectional view showing a structure of a resin case which constitutes an electrolytic capacitor according to the present embodiment and constitutes a housing case of a capacitor element. 3 is a front sectional view showing a structure of a metal case which is a part of the housing case, and FIG. 4 is a front sectional view showing a structure of a housing case including a resin case and a metal case.

First, as shown in FIG. 1, in the electrolytic capacitor of this embodiment, a pair of lead terminals 2 also made of aluminum are connected to a pair of anode foil and cathode foil made of high-purity aluminum foil, and The capacitor element 1 formed by winding capacitor paper between the anode foil and the cathode foil is used. The surface of the capacitor element 1 is electrochemically roughened with an etching solution or the like in order to increase the surface area of the aluminum anode foil / cathode foil. Then, a dielectric oxide film is formed on the anode foil.

Such a capacitor element 1 is impregnated with a driving electrolytic solution, which is hermetically housed in a cylindrical housing case A having one side as a bottom surface and the other side as an opening to form an electrolytic capacitor. Here, in order to hermetically house the capacitor element 1, as a means for sealing the opening of the housing case A,
The sealing plate 3 is used. The sealing plate 4 is provided with the rivet portion 4 penetrating so as to project on both sides thereof. Then, first, after connecting the lead-out terminal 2 of the capacitor element to the rivet portion 4 protruding on the back surface of the sealing plate 3, the capacitor element is housed in the housing case A. Next, the opening of the housing case A in which the capacitor element is housed is bited into the sealing plate 3 by tightening and sealed.

In the electrolytic capacitor as described above, the housing case A is formed by connecting a cylindrical resin case 5 having a bottom surface made of a transparent resin having a predetermined thickness and a cylindrical metal case 6 having openings at both ends. Configure. As shown in FIG. 3, first, as the metal case 6, in the vicinity of both ends of a cylindrical opening made of metal, locking grooves 8 and 9 protruding inward in a ring shape are respectively formed by drawing. To do. Here, in the metal case 6, the lower end side is the connection side with the resin case 5, the upper end side is the opening side of the housing case, and the lower end side locking groove is the first locking groove 8 and the upper end side locking groove. Is the second locking groove 9. The first and second locking grooves 8 and 9 are formed at predetermined positions, that is, the first locking groove 8 is a resin case 5 which will be described later.
The thickness of the protrusion 10 and the rubber ring 12 of the second locking groove 9
Is appropriately formed at a position where the tip of the metal case can be wound and processed according to the thickness of the sealing plate 3.

On the other hand, as shown in FIG. 2, the resin case 5 is provided with a projecting portion 10 projecting outward in a ring shape from the outer peripheral edge at the opening which is the upper end of the resin case. The outer circumference of the protrusion 10 and the inner circumference of the metal case 6 are formed to have the same diameter.

Then, as shown in FIG. 4, the upper end of the resin case 5 is inserted into the opening on the lower end side of the metal case 6. At this time, the resin case 5 is inserted until the protrusion 10 at the upper end abuts on the first locking groove 8 of the metal case 6 and is locked. This means that the protrusion 10 of the resin case 5 is in close contact with the inner peripheral surface of the metal case 6, and the resin case 6 is inserted into the metal case 5 by the size of the protrusion 10 at regular intervals. It is in a state. Between the outer peripheral surface of the resin case 5 and the inner peripheral surface of the metal case 6 in this state,
The rubber ring 12 which is a ring-shaped elastic member is fitted. The rubber ring 12 is brought into close contact with the lower surface of the protrusion 10.

Thereafter, the lower end of the metal case 6 which is below the rubber ring is pressed by a winding process so that the lower surface of the rubber ring 12 is pushed into the lower surface of the rubber ring 12 to press the rubber ring 12 toward the protruding portion 10. It is formed as the part 13. Due to this pressing portion 13, the protruding portion 10 of the resin case 5 is sandwiched and fixed by the first locking groove 8 of the metal case 6 and the rubber ring 12. Therefore, the resin case 5
Are connected in close contact with the metal case 6 via a rubber ring.

Regarding the electrolytic capacitor according to the present embodiment as described above, by comparing the characteristics with the conventional electrolytic capacitor,
The effects will be described. That is, a conventional electrolytic capacitor (conventional product B) in which a capacitor element is housed in a metal case, together with the electrolytic capacitor according to the present embodiment (invention product A) as described above, is rated at 85V of 600V-5500 μF.
Manufactured for ℃. In the conventional product B, the configuration of the capacitor element and the sealing plate and the connection of the rivet portion and the lead-out terminal are exactly the same, but the configuration of the housing case that houses the capacitor element is different.

For both the product A of the present invention and the product B of the prior art as described above, the results at the time of performing a life test by applying 400 V at 105 ° C. for 2000 hours (h) were examined. The results are shown in Table 1.

[0029]

[Table 1]

In this table, the confirmation result of the capacitor element after the test for 2000 hours was conducted by inspecting the inside of the containing case by opening the sealing plate of the case. As a result, in both cases, the occurrence of corrosion is similarly detected in the internal lead terminal drawn from the capacitor element.

Here, in the conventional product B, since the housing case is made of metal, it is impossible to visually confirm the inside. Therefore, you will not notice the corrosion of the lead terminals,
If the test is continued, corrosion will progress, and eventually the internal lead terminals will be disconnected and the function of the capacitor will be lost. As described above, in the conventional product B, the deterioration state of the electrolytic capacitor cannot be grasped and the electrolytic capacitor is continuously used. When the function of the capacitor is lost, the reliability of the device used is deteriorated. .

On the other hand, in the case of the product A of the present invention, since the case accommodating the capacitor element is made of transparent resin, the state inside the case can be visually determined. Therefore, the state of the capacitor element inside the case can be confirmed.
In this case, it has been confirmed from the outside of the case that the surface of the capacitor element has turned quite brown.
Here, it is known that in the capacitor element, the driving electrolytic solution deteriorates with time due to the use of the electrolytic capacitor, and as a result, the color changes to brown with time. Therefore, in the product A of the present invention, it can be determined that the electrolytic capacitor is considerably deteriorated from the degree of color change of the capacitor element. This agrees with the confirmation result obtained by opening the sealing plate of the housing case.

As can be seen from the above test results, according to the electrolytic capacitor of this embodiment, since the transparent resin is used in a part of the case in which the capacitor element is housed, the state inside the case can be changed from the outside. You can check. As a result, the degree of color change of the capacitor element can be confirmed from the outside of the housing case, and the degree of deterioration over time can be easily visually determined.

Moreover, in the housing case A, since the peripheral surface of the projecting portion 10 formed in a ring shape on the outer peripheral surface of the resin case 5 and the inner peripheral surface of the metal case 6 have the same diameter, the resin case 5
When is inserted into the metal case 6, the protrusion 10 comes into close contact with the metal case 6. Further, the upper surface of the protruding portion 10 of the resin case 5 is locked in the first locking groove 8 of the metal case, and
The lower surface is fixed by the rubber ring 12. In particular, the rubber ring 12 has a pressing portion 13 formed at the lower end of the metal case 6.
As a result, the protrusion 10 is pressed in the direction of the first locking groove 8. As a result, the resin case and the metal case are securely fixed. As described above, since the resin case 5 and the metal case 6 are tightly fixed and connected to each other, in the housing case A of the present embodiment, the connection portion can be kept in a highly airtight state.

Therefore, in this embodiment, the life of the electrolytic capacitor can be accurately and easily predicted, and a new capacitor can be replaced at an appropriate time before the function of the capacitor is lost. As a result, the electrolytic capacitor can be used with peace of mind until an appropriate time, which is longer than in the conventional case. This can reduce the number of times the electrolytic capacitor incorporated in the equipment is replaced, and as a result, the cost of the equipment used can be reduced. Moreover, in the electrolytic capacitor of this embodiment, since the housing case is maintained in a highly airtight state, it is possible to prevent deterioration of the capacitor element inside the case due to the outside air. As a result, in a device incorporating an electrolytic capacitor, excellent capacitor characteristics and reliability can be secured without losing the function of the capacitor, and the device can be used with peace of mind.

The present invention is not limited to the above-described embodiment, but the specific structure of the housing case can be changed as appropriate. For example, the metal case 6 is a metal case 6.
As the positioning means when the transparent resin case 5 is inserted therein, a configuration other than the formation of the first locking groove 8 can be adopted. As an example thereof, as shown in FIG. 5, the metal case 6 has a step portion 18 protruding outward in the lower end opening. As a result, the metal case 6 has a larger inner diameter below the step portion 18 than at the upper portion. At this time, the inner diameter below the step portion 18 is configured to be the same as the outer diameter of the protruding portion 10 formed in the resin case.

With this structure, the resin case 5 inserted into the lower end opening of the metal case 6 slides on the inner peripheral surface of the metal case below the step portion 18, and the protruding portion 10 of the resin case 5 slides on the step portion 18. Will be abutted against and locked. After that, a rubber ring is arranged in the same manner as in the above-mentioned embodiment, and the lower end of the metal case is formed as a pressing portion by a winding process, whereby the rubber ring is pressed in the step direction. Even with this configuration,
Similar to the above-described embodiment, the transparent resin case 5 and the metal case 6 can be closely fixed to each other to form a housing case in which a connected state with high airtightness is secured, and similar effects can be obtained.

Further, the present invention is not limited to the use of the rubber ring as the pressing means for pressing the protruding portion of the resin case toward the positioning means of the metal case to closely fix the resin case and the metal case. A ring-shaped synthetic resin, a coil spring, or the like can be used as the elastic member having elasticity and heat resistance. It should be noted that the protruding portion of the resin case may be formed with an acute-angled protrusion that can be bite into the elastic member as a fixing means for fixing the elastic member. Further, without using such an elastic member, the resin case can be directly pressed by the pressing portion provided at the lower end of the metal case so as to be closely fixed.

Further, in the present invention, the housing case A is not limited to being composed of two cases, that is, the resin case 5 on the bottom side of the housing case and the metal case 6 on the opening side of the housing case. It is also possible to configure with a plurality of metal cases and resin cases. For example, it is possible to adopt a configuration in which a metal case that is the bottom side of the housing case and the metal case that is the opening side is connected to both open ends of a cylindrical resin case that is open at both ends. Also in this case, the resin case is inserted into the metal case and tightly fixed, thereby achieving a highly airtight connection. Also in the electrolytic capacitor using the housing case thus configured, the inside of the housing case can be visually confirmed. Thereby, the degree of color change of the capacitor element can be determined, and the deterioration state of the electrolytic capacitor can be determined.

Further, in the electrolytic capacitor and the method of manufacturing the same of the present invention, the internal structure of the housing case can be changed as appropriate. For example, the electrodes and lead terminals of the capacitor element are not limited to being made of aluminum, and other materials,
For example, the same effect can be obtained even when an electrode or terminal made of tantalum, niobium, titanium, magnesium, zirconium, or the like is used.

[0041]

As described above, according to the present invention, the case for accommodating the capacitor element is composed of a metal case and a transparent resin case, which are connected in a highly airtight state by closely fixing. Therefore, the degree of deterioration with time of the electrolytic capacitor can be visually determined to easily predict the life, and an electrolytic capacitor having excellent reliability and a manufacturing method thereof can be provided.

[Brief description of drawings]

FIG. 1 is a front sectional view of an essential part showing an embodiment of an electrolytic capacitor of the present invention.

FIG. 2 is a front cross-sectional view showing a resin case forming FIG.

FIG. 3 is a front cross-sectional view showing a state before inserting and connecting a resin case with respect to the metal case constituting FIG.

FIG. 4 is a front cross-sectional view showing a state in which the resin case of FIG. 2 is inserted into the metal case of FIG.

FIG. 5 is a front sectional view showing another embodiment of the present invention.

FIG. 6 is a front cross-sectional view of an essential part showing a conventional electrolytic capacitor.

[Explanation of symbols]

 A: Housing case 1, 21 ... Capacitor element 2, 22 ... Lead-out terminal 3, 23 ... Sealing plate 4, 25 ... Rivet part 5 ... Transparent resin case 6, 25 ... Metal case 8, 9 ... Locking groove 10 ... Projection part 12 ... Rubber ring 13 ... Pressing part 18 ... Step part

Claims (5)

[Claims] 1. A capacitor element is formed by winding an anode foil made of a valve metal and a cathode foil with a spacer interposed therebetween to form a capacitor element.
In an electrolytic capacitor in which this capacitor element is impregnated with a driving electrolytic solution and hermetically accommodated in a housing case, the housing case includes a metal case and a transparent resin case, and the inner peripheral surface of the metal case and the An electrolytic capacitor in which the end of a resin case is closely fixed and connected. 2. The resin case is formed in a cylindrical shape with one end serving as a bottom surface and the other end opening, and the outer peripheral edge of the opened end has a peripheral surface protruding outward. A ring-shaped protrusion having the same diameter as the inner circumference of the metal case is provided, and the metal case is formed in a cylindrical shape with both ends open, and the peripheral surface of one opening of the metal case is The positioning means for locking the protrusion is formed so as to protrude inward in a ring shape.
The described electrolytic capacitor. 3. The electrolytic capacitor according to claim 2, wherein the protruding portion of the resin case is pressed by the pressing means toward the positioning means of the metal case. 4. The electrolytic capacitor according to claim 3, wherein an elastic member is provided as the pressing means, or a pressing portion is formed at the tip of the metal case. 5. A capacitor element is formed by winding an anode foil and a cathode foil made of a valve metal with a spacer interposed therebetween to form a capacitor element.
In a method of manufacturing an electrolytic capacitor in which this capacitor element is impregnated with a driving electrolytic solution and hermetically housed in a housing case, a positioning means projecting inward in a ring shape in a cylindrical metal case with both ends open. A cylindrical transparent resin case having a bottom surface at one end and an opening at the other end, and the outer surface of the opening is projected to the outside and the peripheral surface is the inner circumference of the metal case. Provided with a ring-shaped protrusion having the same diameter as the above, in one opening of the metal case,
The end of the resin case on the opening side is inserted until the protrusion comes into contact with the positioning means, and the protrusion is pressed in the direction of the positioning means by the pressing means to tightly fix the resin case and the metal case. A method of manufacturing an electrolytic capacitor, which comprises forming a housing case.