JPH11288846A - Four-terminal capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a four-terminal capacitor, which can realize high-frequency coutermeasure through low-ESR realization and low-ESR realization, has a high current capacity and high capacity, low impedance and little heating. SOLUTION: A valve-metal foil 23 for an anode, in which rough-surface formation is performed and a dielectric oxide film layer 25 are formed and a metal foil 24 for current collection are laminated via a cathode conducting macromolecule layer 26, so that the foils intersect with each other. Anode terminals 21 and cathode terminals 22 are connected to the respective both ends of the respective metal foils 23 and 24. For the anode valve metal foil 23, the aluminum foil having a bulk layer, whose surface has not been roughened, is used at the inner cross section. For the metal foil 24 for the current collector aluminum foil, for which the same aluminum foil, an Ni foil a Cu foil or carbon is added, is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electrolytic capacitor used for an electric circuit such as a power supply.

[0002]

2. Description of the Related Art Conventionally, electrolytic capacitors using valve metals such as aluminum and tantalum,
A multilayer ceramic capacitor using Pd, Ni, or the like as an electrode and using barium titanate or the like as a dielectric is known. Although these capacitors are used in most electric circuits such as power supply circuits, most capacitors have a two-terminal structure as an extraction electrode. On the other hand, in recent years, miniaturization of electric circuits and adaptation to high frequencies have been required, and accordingly, capacitors have also been required to have large capacitance and low impedance.
In particular, a power supply circuit for driving a CPU or a switching power supply circuit of a computer is required to have high absorptivity for noise and ripple current for high frequency in circuit design.
There is a strong demand for a capacitor that can realize R (equivalent series resistance), low ESL (equivalent series inductance), high ripple current resistance, and large capacity. In order to meet such a demand, the use of a conductive polymer having high electric conductivity as a solid electrolyte for a cathode of an electrolytic capacitor has been studied and developed, particularly for the purpose of reducing the ESR.

A structure of a conventional wound type aluminum electrolytic capacitor will be described with reference to FIG. Anode electrode foil 8 having a roughened surface and a dielectric oxide film layer formed on the surface
A separator 83 is disposed between the surface-collecting cathode foil 82 and the surface-collected cathode foil 82, and a wound element is used as a capacitor element. This element is sealed in a case together with an electrolytic solution. Leads 84 serving as terminals are led out from an anode electrode foil 81 and a current collection cathode foil 82, respectively.

A structure of a conventional chip multilayer ceramic capacitor will be described with reference to FIG. Pd or N
The electrode layers 91 made of a sintered body such as i and the dielectric layers 92 are alternately laminated, and the electrode layers 91 are alternately led out by the external electrodes 93 serving as terminals.

Further, the structure of a conventional functional tantalum electrolytic capacitor will be described with reference to FIG. FIG.
(A) is a sectional view showing a structure of a conventional functional tantalum electrolytic capacitor, and (b) is a partially enlarged sectional view showing a structure of a capacitor element. In the tantalum capacitor element 101, a dielectric layer 101b is formed on the surface of a tantalum powder sintered body 101c, and a functional polymer layer 101a having conductivity is formed on the surface of the dielectric layer 101b. The functional polymer layer 101a acts as a true cathode,
The functional polymer layer 101a is connected to the cathode terminal 102 by a conductive adhesive layer 103. The anode terminal 104 is connected to a lead 105 extending from the sintered body 101c.
It is a casing.

Further, in order to lower the impedance at a high frequency of about 100 kHz or more, it is necessary to reduce the inductance component, and the invention of a four-terminal type capacitor (Japanese Patent Application Laid-Open Nos. Hei 6-267802 and Hei 6-267802).
-267801, "SP-Cap" (trademark of Matsushita Electric Industrial Co., Ltd., Proceedings of '92 Switching Power Supply System Symposium (refer to S6 (1994) -1-1)), etc.)
Have been reported. On the other hand, there is a demand for the development of a capacitor capable of supplying a relatively large current to the primary side and the secondary side of the power supply as well as supporting high frequencies. JP-A-4-32214) has also been reported.

[0007]

However, the above-mentioned conventional wound type aluminum electrolytic capacitor has a high impedance because it uses an electrolytic solution containing ethylene glycol or the like as a main solvent. Therefore, there is a disadvantage that the inductance component is high. Further, in a conventional functional tantalum electrolytic capacitor, the ESR is reduced by using a conductive polymer as an electrolyte, but the increase in capacity is insufficient. Also, conventional chip multilayer ceramic capacitors have a limit in increasing the capacity as compared with conventional aluminum electrolytic capacitors and the like. On the other hand, the conventional invention has a low ESL by adopting a four-terminal structure.
(Reducing the inductance component), but the increase in capacity is insufficient. Further, for example, a relatively large current of several A to several tens A such as a primary side or a secondary side of a power supply. Where the capacitor flows, it cannot be used as a capacitor capable of flowing a large current in addition to supporting high frequencies, such as failure of the capacitor itself due to heat generation.

[0008] The reason for this is that in a conventional wound type aluminum electrolytic capacitor, an elongated electrode foil is wound,
Even if a four-terminal structure is adopted, the foil resistance is relatively high, and the element easily generates heat. In addition, although the conventional functional tantalum electrolytic capacitor can achieve a certain degree of low ESR by using a functional polymer, it is not easy to increase the capacity per volume and increase the capacity because it uses a sintered body. In addition, it is not easy to configure a four-terminal structure.
The multilayer ceramic capacitor described in Japanese Patent Laid-Open No. 4-32214 has a four-terminal structure and has a low ESL.
And the current capacity is increased by configuring the two electrode layers as one set. However, since the electrode layer material is a sintered metal and its thickness is several μm in manufacturing, The current value that can be passed is at most several amperes, and it is expected that the number of stacked layers must be increased when used in a circuit where a large amount of current flows, such as a primary side or a secondary side of a power supply.
On the other hand, increasing the number of stacked layers is not easy in terms of manufacturing. Even if many electrode layers can be stacked, the volume per capacitor increases. Also, make the electrode layer thick 3 μm
Even if the thickness is increased, delamination (peeling of the dielectric layer and the electrode layer) occurs in the manufacturing process, and it is difficult to realize.

FIGS. 13 and 14 show these problems.
This will be described with reference to FIG. FIG. 13 shows an equivalent circuit (inside a dotted line) of a conventional two-terminal capacitor. FIG. 14 is an equivalent circuit showing the problem of the conventional four-terminal capacitor (inside the dotted line).
It is. In order to make a capacitor compatible with high frequency, ES
It is necessary to reduce R (equivalent series resistance) 111 and ESL (equivalent series inductance) 112, and it is possible to reduce ESR mainly by using a conductive polymer for the electrolyte or improving the current collector. Further, low ESL can be realized by using a four-terminal type as shown in FIG. However, in the conventional four-terminal structure shown in FIG. 14, the impedance as an element is high, and the resistances R + (anode circuit resistance) 121 and R-
(Circuit resistance of cathode current collector) 122 greatly contributes to heat generation when a current flows, and cannot be used for a circuit such as a primary side or a secondary side of a power supply through which a relatively large current flows. In order to satisfy the characteristics, a means for reducing R + 121 and R-122 is required.

As described above, the conventional capacitor cannot satisfy the characteristics of low impedance and high capacitance, and furthermore, has a high capacity for a relatively high current such as a primary side or a secondary side of a power supply. When used in a circuit, there is a problem that the element generates a large amount of heat and a relatively large current cannot flow.

There is exactly the problem to be solved by the present invention, and the object and realizing means of the present invention are different from the conventional one. The present invention is to alternately laminate the electrode foil for the anode and the cathode current collector, and further use the aluminum foil having a bulk layer in the internal cross section as the electrode foil or the metal foil of Ni or the like for the current collector electrode. It solves the problems that exist in conventional capacitors, and is used not only for high-frequency operation by low ESR and low ESL, but also for high-frequency operation circuits such as the primary and secondary sides of the power supply where relatively large circuit current flows. It is an object of the present invention to provide a four-terminal capacitor having a high current capacity, a high capacity, a low impedance, and a small heat generation.

[0012]

To achieve the above object, a four-terminal capacitor according to the present invention comprises a valve metal foil for an anode having a dielectric oxide film layer formed on a surface thereof, a metal foil for a current collector, A cathode conductive polymer layer disposed between the anode valve metal foil and the current collector metal foil, and an anode terminal and a cathode terminal for external connection, wherein the anode valve The surface of the metal foil is roughened, and the anode valve metal foil and the current collector metal foil are alternately laminated via the cathode conductive polymer layer, and each of the anode valves Two different places of the metal foil are electrically connected to two separate anode terminals, and two different places of each of the current collector metal foils are electrically connected to two separate cathode terminals. It is characterized by having been done. According to such a configuration, low ESR is achieved,
Not only can high frequency response by low ESL be realized,
The present invention can also be used in a circuit in which a relatively large current flows, such as a primary side or a secondary side of a power supply, and can obtain a four-terminal capacitor having a high current capacity, a high capacity, a low impedance, and a small heat generation.

In the above structure, a line connecting two separate anode terminals (or two connection points connected to each anode terminal in the anode valve metal foil) and two separate anode terminals are connected. Between the cathode terminals (or between two connection points connected to each cathode terminal in the current collector metal foil)
May or may not intersect when viewed from the stacking direction.

Further, in the above structure, the valve metal foil for the anode and the metal foil for the current collector are aluminum foils whose surfaces are roughened, and the valve metal foil for the anode and the metal foil for the current collector are provided. It is preferable to have a bulk layer that has not been subjected to surface roughening treatment on the internal cross section of each of them.

Preferably, the metal foil for a current collector is a nickel foil, a copper foil, or an aluminum foil to which carbon particles are added.

Further, the anode valve metal foil is an aluminum foil having a roughened surface, and has a bulk layer which has not been subjected to a surface roughening treatment on an inner cross section of the anode valve metal foil. The body metal foil is preferably a nickel foil, a copper foil, or an aluminum foil to which carbon particles are added.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(Embodiment 1) FIG. 1 is a structural view showing an embodiment of a structure of a capacitor element portion of a four-terminal capacitor according to the present invention. A dielectric oxide film layer 13 is formed by anodic oxidation (chemical formation) on the surface of the anode valve metal foil 11 whose surface is roughened by electrolytic etching or the like and whose surface area is enlarged. The anode valve metal foil 11 and the current collector metal foil 12 intersect with each other and overlap each other at substantially the center. No dielectric oxide film layer is formed on both ends of the valve metal foil for anode 11 or portions of the end face where the anode terminals are to be connected in order to establish conduction. A capacitor element is formed by forming a conductive polymer layer such as polypyrrole serving as a true cathode between the valve metal foil for anode 11 and the metal foil 12 for current collector. The use of a conductive polymer layer having relatively high electrical conductivity as a true cathode and direct contact between the current collector metal foil 12 and the conductive polymer layer can realize low ESR, Valve metal foil 11 and current collector metal foil 12
Are alternately stacked to realize a low ESL.

Next, FIG. 2 is a configuration diagram showing one embodiment of the configuration of the four-terminal capacitor of the present invention. FIG. 2A is an external perspective view, and FIG. 2B is a partially cutaway perspective view showing an internal structure. In FIG. 2, 21 is an anode terminal, 22 is a cathode terminal, 23 is an anode valve metal foil, 2
Reference numeral 4 denotes a metal foil for a current collector, 25 denotes a dielectric oxide film layer, 26 denotes a conductive polymer layer for a cathode, and 27 denotes a mold resin. A required number of anode valve metal foils 23 and current collector metal foils 24 each having a surface roughened and having a dielectric oxide film layer 25 formed on the surface excluding both ends or end faces are laminated so as to intersect with each other by a required number. The cathode conductive polymer layer 26 is filled between the anode valve metal foil 23 and the current collector metal foil 24. The surface of the current collector metal foil 24 may be roughened. The anode terminal 21 is connected to both ends of the anode valve metal foil 23, and the cathode terminal 22 is connected to both ends of the current collector metal foil 24, respectively. With the configuration as shown in FIG. 2, a large capacity can be realized in addition to low ESR and low ESL.

FIG. 3 shows a cross-sectional electron micrograph of one embodiment of the anode valve metal foil which can be used in the four-terminal capacitor of the present invention. The anode valve metal foil shown in FIG. 3 is an aluminum foil, and columnar pits (holes) 32 are formed by electrolytic direct current etching, so that the surface area is increased. In FIG. 3, reference numeral 31 denotes a bulk layer that has not been subjected to a surface roughening treatment. The foil thickness in FIG. 3 is about 150 μm,
The thickness of the bulk layer 31 is about 15 μm. The thickness of the bulk layer 31 can be freely controlled by controlling the length of the columnar pits 32 and controlling the foil thickness, and can be made thicker or thinner. Therefore, the structure of the valve metal foil for the anode is not limited to this embodiment. The columnar pits 32 are also used for a high-voltage four-terminal capacitor, and can form a dielectric oxide film layer for a high voltage (up to about 5800 angstroms (10 angstroms / 1 V)). In order to obtain more capacity, the dielectric oxide film layer may be made thinner, and the surface area may be increased by AC etching or the like.

FIG. 4 shows a cross-sectional electron micrograph of one embodiment of a metal foil for a current collector which can be used in the four-terminal capacitor of the present invention. The metal foil for a current collector shown in FIG. 4 is an aluminum foil, which is roughened by AC etching and has an increased surface area. In FIG. 4, reference numeral 41 denotes a bulk layer,
2 is an etching pit (hole). The foil thickness in FIG. 4 is about 90 μm, and the thickness of the bulk layer 41 is about 45 μm
It is. The thickness of this bulk layer can be made thicker or thinner depending on the etching conditions and foil thickness. The configuration of the current collector metal foil is not limited to this embodiment.

As described above, by using the valve metal foil for the anode and the metal foil for the current collector having the bulk layer whose inner cross section is not roughened, the circuit current flows through the bulk layer in the present invention. Therefore, it is possible to realize a four-terminal capacitor that generates less heat from the element and has a large current capacity. Also, to laminate short electrode foils,
The cross-sectional area through which current flows increases due to lamination, and the resistance can be reduced. For example, the volume resistivity of Al is set to about 2.6E-
Assuming that 6 Ωcm, the calorific value when a current of 1 A is applied to an electrode foil having a thickness of 100 μm, an unetched bulk layer of 50 μm, a length of 17 cm, and a width of 1.5 cm is about 6 mW and a current of 10 A The calorific value when flowing is about 0.6 W. On the other hand, the above foil is divided into 10 equal parts,
When 10 layers are laminated, the cross-sectional area is 10 times and the length is 1/10.
Therefore, the resistance is reduced to about 1/100, and the calorific value can be reduced to about 1/100.

On the other hand, the current capacity can also be increased by using a Ni foil, a Cu foil, or an aluminum foil to which carbon particles are added, whose thickness can be freely set, as the metal foil for the current collector. The volume resistivity of Ta is about 10.4E-6Ωc
m, Al is about 2.6E-6Ωcm, Ni is about 6.8E-
6 Ωcm, Cu is about 1.7E-6 Ωcm. From this, it is clear that the current capacity can be increased by using an aluminum foil, a Ni foil, or a Cu foil having a bulk layer.

Also, since it is difficult for Ni to form an oxide layer on the surface, the interface resistance with the conductive polymer layer can be reduced, and the ESR can be further reduced. Furthermore, since the capacity due to the oxide film does not occur in the metal foil for the current collector, the capacity of the capacitor can be increased.

FIG. 5 is a sectional view of a carbon-added aluminum foil which can be used in the four-terminal capacitor of the present invention. In FIG. 5, reference numeral 51 denotes aluminum, and 52 denotes conductive carbon particles. The aluminum foil with carbon has a structure in which conductive carbon particles are exposed on the surface, so that the conductive polymer layer and the carbon particles are in contact with each other without an oxide film, so that an oxide film is formed. The interface resistance can be reduced and a low ESR can be realized as compared with the case where an easy aluminum foil is used. Further, conventionally, the conductive polymer layer that could not be formed by the electrolytic polymerization method can be formed by electrolytic polymerization on the aluminum foil to which the carbon particles are added by using the aluminum foil to which the carbon particles are added,
The manufacturing cost of the four-terminal capacitor of the present invention can be reduced.

When a Cu foil is used, the Cu foil easily forms an oxide layer, but has a small volume resistivity as a metal, and can flow current most as a metal foil for a current collector.

As described above, by adopting the first embodiment, a four-terminal capacitor having a low impedance and a very large current capacity can be realized.

FIG. 6 is an equivalent circuit diagram showing the concept of the four-terminal capacitor of the present invention. According to the present invention, a low-impedance, low-ESR, low-ESL four-terminal capacitor close to an equivalent circuit as shown in FIG. 6 can be realized.

In the description of the first embodiment, the line connecting the two separate anode terminals 21 and 21 and the line connecting the two separate cathode terminals 22 and 22 are:
Although they are configured to intersect when viewed from the lamination direction, the terminal configuration is not limited to this.

FIG. 7 shows another configuration example of the four-terminal capacitor of the present invention. In FIG. 7A, reference numeral 61 denotes a rectangular or square valve metal foil for an anode, 62 denotes a metal foil for a current collector having substantially the same shape as the valve metal foil 61 for an anode, and 63 denotes a dielectric oxide film layer. The anode valve metal foil 61 has cutouts 61a cut out in a rectangular shape at two opposing corners of the four corners. Similarly, the metal foil 62 for the current collector also has a cutout portion 62 cut out in a rectangular shape at two opposing corners of the four corners.
a. However, as shown, the notch 62a is formed at a position different from the notch 61a when the anode valve metal foil 61 and the current collector metal foil 62 are laminated. In addition, a dielectric oxide film layer 63 is formed on portions of the anode valve metal foil 61 except for a part of both ends connected to the anode terminal. The anode valve metal foil 61 and the current collector metal foil 62 configured as described above are sequentially laminated by a required number via a cathode conductive polymer layer (not shown).
Different anode terminals are connected to the two corner portions 61b, and different cathode terminals are connected to the two corner portions 62b of each current collector metal foil 62. Thus, a four-terminal capacitor configured such that the line connecting the two anode terminals and the line connecting the two cathode terminals intersect when viewed in the stacking direction can be configured. In the above configuration, it is possible to use an anode valve metal foil 61 ′ having a configuration shown in FIG. 7B instead of the anode valve metal foil 61. This anode valve metal foil 61 'has a dielectric oxide film layer 63 formed thereon except for an end face 64 to which an anode terminal is to be connected.

FIG. 8 shows still another configuration example of the four-terminal capacitor of the present invention. 8A, reference numeral 66 denotes a rectangular or square valve metal foil for an anode, and 67 denotes a valve metal foil 66 for an anode.
Reference numeral 68 denotes a current collector metal foil having substantially the same shape as that of the current collector. The anode valve metal foil 66 has a rectangular cutout 66a at two adjacent corners among the four corners. Similarly, the metal foil 67 for the current collector also has a notch 6 formed by cutting two adjacent corners of the four corners into a rectangular shape.
7a. However, as shown, the notch 67a is formed at a position different from the notch 66a when the anode valve metal foil 66 and the current collector metal foil 67 are laminated. Further, a dielectric oxide film layer 68 is formed on the anode valve metal foil 66 except for a part of both ends connected to the anode terminal. The anode valve metal foil 66 and the current collector metal foil 67 configured as described above are sequentially laminated by a required number via a cathode conductive polymer layer (not shown). Different anode terminals are connected to the two corners 66b, and different cathode terminals are connected to the two corners 67b of each current collector metal foil 67. Thus, a four-terminal capacitor can be configured such that the line connecting the two anode terminals and the line connecting the two cathode terminals do not intersect when viewed in the stacking direction. In the above configuration, it is also possible to use an anode valve metal foil 66 ′ having a configuration shown in FIG. 8B instead of the anode valve metal foil 66. The anode valve metal foil 66 'is connected to an end face 69 to which an anode terminal is to be connected.
Except for the above, a dielectric oxide film layer 63 is formed.

Further, in the above embodiment, it goes without saying that the dimensions of the final product can be changed according to the capacitance and the current capacity. It is also possible to determine the thickness of the bulk layer of the valve metal foil for the anode and the thickness of the metal foil for the current collector according to the desired current capacity.

[0033]

(Example 1) A four-terminal capacitor shown in FIG. 2 was manufactured. Purity 99.98 as the anode valve metal foil 23
% Or more and an aluminum foil having a thickness of 100 μm was used. The surface of the anode valve metal foil 23 has a concentration of 10 wt% and a liquid temperature of 35 ° C.
Was subjected to AC etching in a hydrochloric acid-based solution to roughen the surface, and then this foil was cut into a rectangle and used. Valve metal foil for anode 23
The thickness of the bulk layer was 55 μm. The dielectric oxide film 25 is formed by performing a constant voltage formation at a formation voltage of 12 V except for the both ends of the anode valve metal foil 23 by using an aqueous solution of ammonium adipate having a solution temperature of 60 ° C. and a concentration of 5 wt% as a formation solution. (For 6.3 WV). The current collector metal foil 24 is made of Ni having the same shape as the anode valve metal foil and a thickness of 50 μm.
A foil was used. The cathode terminal 2 is provided on the surface of the current collector metal foil 24.
Except for both ends to be connected to No. 2, polypyrrole was previously formed to a thickness of several μm as the conductive polymer layer 26 for the cathode by electrolytic polymerization. Next, the valve metal foil 23 for the anode and the metal foil 24 for the current collector were separated by about 90
Ten layers were laminated so as to intersect each other, and both ends of the valve metal foil for anode 23 and the metal foil for current collector 24 were caulked (mechanically pressed) together with the anode terminal 21 and the cathode terminal 22, respectively, in order to establish conduction. Next, after only the terminal joint is covered with the mold resin 27, the cathode conductive polymer layer 26 is impregnated between the current collector metal foil 24 and the anode valve metal foil 23 using an impregnation chemical polymerization method. Was completely formed. Next, these elements were entirely molded with a molding resin 27 except for the terminal surfaces to obtain a four-terminal capacitor. The case size is D size.

Example 2 A four-terminal capacitor shown in FIG. 2 was manufactured. 99.9 purity as the anode valve metal foil 23
An aluminum foil with a thickness of 8% or more and a thickness of 100 μm was used.
The surface of the anode valve metal foil 23 is made to have a concentration of 10 wt% and a liquid temperature of 35.
After AC etching and roughening in hydrochloric acid solution at ℃
This foil was cut into a rectangle and used. Valve metal foil for anode 2
The thickness of the bulk layer of No. 3 was 55 μm. The dielectric oxide film 25 is formed by performing a constant voltage formation at a formation voltage of 12 V except for the both ends of the anode valve metal foil 23 by using an aqueous solution of ammonium adipate having a solution temperature of 60 ° C. and a concentration of 5 wt% as a formation solution. Was. As the collector metal foil 24, a conductive carbon-added aluminum foil having substantially the same shape as the anode valve metal foil and a thickness of 50 μm was used. The carbon-added aluminum foil was prepared by applying conductive carbon onto an aluminum foil having a roughened surface, followed by pressing, and then further roughening the surface. Next, on the surface of the current collector metal foil 24,
Except for both ends to be connected to the cathode terminal 22, polypyrrole was previously formed to a thickness of several μm as a conductive polymer layer 26 for a cathode by an electric field polymerization method. Next, the anode valve metal foil 23 and the current collector are laminated in ten layers so that the longitudinal direction thereof intersects at about 90 in the longitudinal direction. Both ends of the metal foil 24 were caulked (mechanically pressed) together with the anode terminal 21 and the cathode terminal 22, respectively. Next, after only the terminal joint is covered with the mold resin 27, the cathode conductive polymer layer 26 is impregnated between the current collector metal foil 24 and the anode valve metal foil 23 using an impregnation chemical polymerization method. Was completely formed. Next, these elements were entirely molded with a molding resin 27 except for the terminal surfaces to obtain a four-terminal capacitor. The case size is D size.

(Comparative Example) A wound aluminum electrolytic capacitor (105 ° C. product, 400 WV, formation voltage 580 V) has a basic structure, and an anode lead and a cathode lead are provided at both ends of the anode electrode foil and the collector cathode foil, respectively. Derived at each location,
These were wound through a separator to form a capacitor element. Electrode foil and cathode foil are 19cm long and 2c wide
m. The surface of the anode electrode foil was roughened by DC etching in a hydrochloric acid-sulfuric acid solution at a liquid temperature of 85 ° C. to form columnar pits, and the surface was roughened. The formation of the dielectric oxide film was carried out at a constant voltage of 580 V by using an aqueous solution of ammonium adipate having a solution temperature of 60 ° C. and a concentration of 5 wt% as a formation solution. At this time, the thickness of the bulk layer of the anode electrode foil was 3 to 5 μm. 50 μm thickness for the current collector cathode foil
Using aluminum foil, concentration 10wt%, liquid temperature 35 ℃
Was subjected to AC etching in a hydrochloric acid-based solution to roughen the surface. Furthermore, the above capacitor element is placed in an aluminum case (D: 30 m
m, L: 30 mm) and impregnated with the electrolyte under reduced pressure.
The opening was sealed to form a wound four-terminal capacitor.
The formation of the lead connection portion is performed in an electrolytic solution after sealing.

The performance when the four-terminal capacitors in Examples 1, 2 and Comparative Examples are used as four-terminal capacitors will be described below with reference to Table 1.

[0037]

[Table 1]

In Table 1, when the amount of heat generated is 1 A, the capacity is 120 Hz, the impedance Z and the ESR are 1 MH.
It is a measured value at z.

As is clear from Table 1, in Examples 1 and 2, the amount of heat generated is extremely small due to the four-terminal structure of the present invention. Table 1
"Not generating heat" means that the calorific value is extremely small. In the first embodiment, the ESR is significantly reduced, and in the second embodiment, the ESR is further reduced.
Further, by using the four-terminal capacitor of the present invention, low impedance (low L component) at high frequencies can be achieved.

Example 3 A four-terminal capacitor shown in FIG. 2 was manufactured. 99.9 purity as the anode valve metal foil 23
An aluminum foil having a thickness of 100 μm, a width of 5 mm, and a length of 25 mm at 8% or more was used. The valve metal foil 23 for the anode has a concentration of 1
Pits were formed by AC etching in a hydrochloric acid solution at a liquid temperature of 35 ° C. at a concentration of 0 wt%, and the surface was roughened.
The dielectric oxide film 25 is formed at a liquid temperature of 60 ° C and a concentration of 5 ° C.
An aqueous solution of wt% ammonium adipate was used as a chemical conversion solution, except that both ends of the anode valve metal foil 23 were formed.
At constant voltage. The thickness of the metal foil 24 for the current collector is 9
Using a 0 μm aluminum foil, AC etching was performed in a hydrochloric acid solution having a concentration of 10 wt% and a liquid temperature of 35 ° C., and the roughened foil was cut and used. The width of the current collector metal foil 24 is 5 m
m, length is 25 mm. Next, the metal foil for current collector 2
On the surface of No. 4, polypyrrole was previously formed to a thickness of several μm as a conductive polymer layer for a cathode 26 by an electric field polymerization method except for both ends to be connected to the cathode terminal 22. Next, the anode valve metal foil 23 and the current collector metal foil 24 are laminated in three layers so that the longitudinal direction intersects at about 90 degrees, and the anode valve metal foil 23 and the anode metal foil 23 are collected for conduction. Metal foil 24 for electric body
Were crimped (mechanically pressed) together with the anode terminal 21 and the cathode terminal 22, respectively. Next, after only the terminal joint is covered with the mold resin 27, the cathode conductive polymer layer 26 is impregnated between the current collector metal foil 24 and the anode valve metal foil 23 using an impregnation chemical polymerization method. Was completely formed. Next, these elements were entirely molded with a molding resin 27 except for the terminal surfaces to obtain a four-terminal capacitor.

Next, the characteristic of lowering the L component of the four-terminal capacitor according to the third embodiment will be described with reference to the results of the case where two terminals and four terminals are measured in gain-face impedance measurement. FIG. 9 shows Example 3-4.
The relationship between the frequency and the gain when the terminal capacitor is measured at two terminals and when the terminal capacitor is measured at four terminals is shown. In FIG. 9, 2
The terminal measurement indicates the characteristics when the four-terminal capacitor according to the third embodiment is used as a two-terminal type despite the four-terminal structure. FIG. 4 shows characteristics of low ESL when used as a four-terminal type so as to meet one of the objects of the present invention.

As is apparent from FIG. 9, when used as a four-terminal type, the inductance at high frequencies was reduced, and low impedance was realized. The valve metal foil 23 for anode and the metal foil 24 for current collector were laminated as shown in FIGS. 7 and 8 to manufacture a four-terminal capacitor, and the same evaluation as above was performed. In each case, a decrease in inductance at high frequencies was observed.

As described above, the four-terminal capacitor according to the present embodiment has excellent effects in terms of current capacity and low impedance.

[0044]

As described above, according to the present invention, low ESR
Not only for high frequency due to low power consumption and low ESL, but also for circuits where a relatively large current flows on the primary and secondary sides of the power supply. It has a high current capacity, high capacity, low impedance and heat generation. An advantageous effect of being small is obtained.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a configuration of a capacitor element portion of a four-terminal capacitor according to the present invention.

FIG. 2 is a configuration diagram showing one embodiment of a configuration of a four-terminal capacitor of the present invention.

FIG. 3 is a cross-sectional electron micrograph of one embodiment of an anode valve metal foil that can be used in the four-terminal capacitor of the present invention.

FIG. 4 is a cross-sectional electron micrograph of one embodiment of a metal foil for a current collector that can be used for the four-terminal capacitor of the present invention.

FIG. 5 is a cross-sectional configuration diagram showing an example of a configuration of an aluminum foil to which carbon is added, which can be used for the four-terminal capacitor of the present invention.

FIG. 6 is an equivalent circuit diagram showing the concept of a four-terminal capacitor according to the present invention.

FIG. 7 is an exploded perspective view showing another configuration example of the four-terminal capacitor of the present invention.

FIG. 8 is an exploded perspective view showing still another configuration example of the four-terminal capacitor of the present invention.

FIG. 9 is a diagram showing a frequency-gain relationship in the case of four-terminal measurement and two-terminal measurement of the four-terminal capacitor according to the third embodiment of the present invention.

FIG. 10 is a structural diagram of a conventional wound type aluminum electrolytic capacitor.

FIG. 11 is a sectional view showing the structure of a conventional chip multilayer ceramic capacitor.

FIG. 12 is a structural diagram of a conventional functional tantalum electrolytic capacitor.

FIG. 13 is an equivalent circuit diagram of a conventional two-terminal capacitor.

FIG. 14 is an equivalent circuit diagram showing a problem of a conventional four-terminal capacitor.

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 valve metal foil for anode 12 metal foil for current collector 13 dielectric oxide film layer 21 anode terminal 22 cathode terminal 23 valve metal foil for anode 24 metal foil for current collector 25 dielectric oxide film layer 26 high conductivity for cathode Molecular layer 27 Mold resin 31 Bulk layer 32 Columnar pit 41 Bulk layer 42 Etching pit 51 Aluminum 52 Conductive carbon particles 61, 61 'Valve metal foil for anode 61a Notch 61b Corner 62 Metal foil for current collector 63 Dielectric Body oxide film layer 64 End face 66, 66 'Valve metal foil for anode 66a Notch 66b Corner 67 Metal foil for current collector 68 Oxide film layer for dielectric 69 End face 81 Electrode foil for anode 82 Cathode foil for current collection 83 Separator 84 Lead 91 Electrode layer 92 Dielectric layer 93 External electrode 101 Tantalum capacitor element 101a Functional polymer layer 1 1b dielectric layer 101c tantalum powder sintered 102 a cathode terminal 103 conductive adhesive layer 104 anode terminals 105 lead 106 a molding resin layer 111 equivalent series resistance 112 equivalent series inductance 121 anode internal circuit resistance 122 cathode current collector body internal circuit resistance

Claims (6)

[Claims] An anode valve metal foil having a dielectric oxide film layer formed on a surface thereof, a current collector metal foil, and disposed between the anode valve metal foil and the current collector metal foil. A cathode conductive polymer layer, an anode terminal and a cathode terminal for external connection, the surface of the anode valve metal foil is roughened, and the anode valve metal foil is The metal foil for an electric conductor is alternately laminated via the conductive polymer layer for a cathode, and two different portions of each of the valve metal foils for an anode are electrically connected to two separate anode terminals. And two different points of the current collector metal foil are electrically connected to two separate cathode terminals. 2. A line segment connecting two separate anode terminals,
2. The four-terminal capacitor according to claim 1, wherein a line connecting two separate cathode terminals intersects. 3. A line segment connecting two separate anode terminals,
2. The four-terminal capacitor according to claim 1, wherein a line connecting two separate cathode terminals does not intersect. 4. The anode valve metal foil and the current collector metal foil are aluminum foils whose surfaces are roughened, and the anode valve metal foil and the current collector metal foil have an internal cross section. The four-terminal capacitor according to claim 1, further comprising a bulk layer that has not been subjected to surface roughening. 5. The four-terminal capacitor according to claim 1, wherein the current collector metal foil is made of a nickel foil, a copper foil, or an aluminum foil to which carbon particles are added. 6. The anode valve metal foil is an aluminum foil having a roughened surface, the inner cross section of the anode valve metal foil having a bulk layer that has not been subjected to surface roughening treatment, and a current collector. The body metal foil is a nickel foil or a copper foil or an aluminum foil to which carbon particles are added.
4. The four-terminal capacitor according to any one of 3.