JPH10229032A - Terminal structure for capacitor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a terminal structure for capacitor element which can reduce the impedance value of a capacitor element, which is one of the electrical characteristics of the element and, at the same time, can easily reduce the inductance L of the terminal section of the element. SOLUTION: In a terminal structure for a capacitor element, in which the capacitor element is constituted by winding an electrode foil formed by putting an anode foil 20 and a cathode foil 22 upon another by appropriately interposing separators 24 and 25 between them, after tab terminals 20a and 20b and 22a and 22b have been attached respectively to the anode foil 20 and cathode foil 22 and the terminals 20a, 20b, 22a, and 22b protruding from the capacitor element are coupled with and fixed to conductive rivets protruding from the backside of a sealing plate carrying external terminals on its front surface. The terminals 20a, 20b, 22a, and 22b are respectively attached to the anode foil 20 and the cathode foil 22 with a prescribed interval in between, so that the terminals 22a and 22b overlap the terminals 20a and 20b and all of the terminals are arranged in a straight line in the radial direction from the center of the wound electrode foil, when the foil is wound. Then the terminals 20a and 22b and 20b and 22b, having identical polarities are respectively jointed together, through insulators 26 and 27 and coupled with and fixed to the conductive rivets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal structure of a capacitor element, and particularly to a method of extracting a tab terminal of both electrodes from a capacitor element in order to reduce an impedance value which is an electrical characteristic of an electrolytic capacitor. The present invention relates to a terminal structure of a capacitor element for deriving the tab terminal from a point where the impedance value becomes small.

[0002]

2. Description of the Related Art Conventionally, an electrolytic capacitor has a resonance point. Above the resonance frequency, the capacitor functions not as a capacitor but as a coil, and the impedance value increases as the frequency increases. Electrolytic capacitors generally only need to function at low frequencies, but recently there are an increasing number of applications that have to be useful at very high frequencies.

In order to increase the resonance frequency, what kind of structure should be used for the capacitor element?
The problem arose.

However, in order to increase the resonance frequency, the values of the inductance L and the capacitance C may be reduced according to the following equation (1) (see FIG. 11). If the capacitance C cannot be reduced, the only option is to reduce the inductance L.

[0005]

(Equation 1)

A first method for reducing L is to reduce the length of the electrode wound in a coil. If a foil having a large etching effect is used, and the width of the foil is increased and the number of turns is reduced, the value of the inductance L can be reduced. However, if the width is extremely widened, the effect is adversely affected, so that it is necessary to set an appropriate value.

A second method for reducing the inductance L is as follows.
As shown in FIG. 12A, the method of drawing out the tab terminals 10a, 10a of the anode foil 10 and the cathode foil 12, respectively.
The position a is to be attached to the center of both electrode foils 10 and 12 to be wound. Further, as shown in FIG. 12B, it is also possible to attach the electrode foil to an end of one of the electrode foils (for example, the anode foil 10). FIG.
As shown in (c), if the electrodes are attached to opposite ends of the electrode foils 10 and 12, the value of the inductance L becomes large.

In the above description, the case where one extraction tab terminal is attached to each of both electrodes has been described. However, the value of the inductance L can be further reduced by increasing the number of extraction tab terminals. In this case, if the length between the end of each of the electrode foils 10 and 12 and the lead-out tab terminal is “1”, the tab terminals 10 a and 1
0a and between the tab terminals 12a and 12a may be set to the ratio of "2" (see FIG. 13). In such a case, after winding the electrode foil, it is necessary to connect all of the tab terminals 10a of the anode foil 10 and all of the tab terminals 12a of the cathode foil 12 to the external terminals of the sealing plate at a time. is there.

However, a normal capacitor, particularly a relatively large capacitor, is formed by mounting a sealing plate to which an external connection tab terminal is fixed in an opening of an outer case containing a capacitor element.

In such a capacitor, a tab terminal (a through hole is provided at a tip portion) derived from the capacitor element is provided at a rivet portion of the tab terminal which penetrates the sealing plate and protrudes to the back surface of the sealing plate. It has a connection terminal structure in which it is inserted and locked, and further, a washer or the like is attached and these are integrally pressed.

However, in such a capacitor connection terminal structure, the tab terminal interval derived from the capacitor element and the rivet interval of the terminal protruding on the back surface of the sealing plate are defined by:
It is necessary to make them coincide with each other, and it is necessary to provide the space when the electrode tab terminals are pulled out from the capacitor element. Therefore, the appearance of the capacitor element after winding the electrode foil is as shown in FIG.
a and the cathode extraction tab terminal 12a are spaced apart from each other by the same dimension as the rivet interval of the tab terminal protruding from the back surface of the sealing plate. In this case, the anode foil 10 and the cathode foil 12
As shown in FIG. 15, the positions of the drawn-out tab terminals 10a and 12a correspond to the rivet intervals of the tab terminals protruding from the back surface of the sealing plate, and are equivalent to the circumferential length "A" required for winding. Is required.

The positions of the lead tab terminals 10a and 12a of the anode foil 10 and the cathode foil 12 shown in FIG. 15 show a case where a model diagram is drawn in a strict form. When it is drawn, it becomes, for example, as shown in FIG. 16 and is easily misunderstood.

That is, the capacitor element shown in FIG. 16 is composed of an insulating paper 14, a cathode foil 12, an insulating paper 15, and an anode foil 10.
Are superimposed, started to be wound from the starting end S, wound as shown in FIG. 17, and impregnated with the electrolytic solution. in this case,
On each electrode side (anode foil 10 and cathode foil 12), an arbitrary number of electrode tab terminal groups 11 and 13 are provided over the entire length at required intervals (see FIG. 16). The terminal groups 11 and 13 are grouped for each same polarity as shown in FIG.

Therefore, in FIG. 16, misunderstandings are likely to occur at the positions of the tab terminals of both electrodes and the positions of the tab terminals of the capacitor element after winding the electrode foil. That is, in FIG. 16, the lead tab terminals of the two electrodes are drawn as if they overlap, but each of the electrode tab terminal groups 11 and 13 of the capacitor element 18 after winding of the electrode foil includes an anode and an anode. The point is that they are grouped for each cathode. This is because the positions of the extraction tab terminals of both electrodes in FIG. 16 are simply drawn, and unlike the original contents, misunderstandings are likely to occur.

Further, in the case of a relatively large capacitor as described above, when leading out both electrode tab terminals with a required interval from the capacitor element, the impedance, which is the electrical characteristic of the capacitor, is greatly affected, and the interval is large. As the width becomes wider (peripheral length between both electrode lead-out tab terminals in the wound structure), the value of the impedance increases (see FIG. 18). That is, FIG. 18 shows the positions where the electrode tab terminals 10a and 12a are pulled out and the impedance (| Z
|) And the equivalent series resistance (ESR). The frequency characteristics of the impedance and the equivalent series resistance in this case are as shown in FIG.

[0016]

However, in the above-mentioned conventional electrolytic capacitor, as a means for reducing the interval between the lead-out tab terminals derived from the electrode foil wound in a coil shape, for example, it is projected on the back surface of the sealing plate. It is proposed to reduce the rivet spacing of the terminals. However, in this case, it is not practical because the distance between the external terminals on the surface of the sealing plate penetrating the sealing plate is also limited.

In the first method for shortening the length of the electrode, an electrode foil having a large etching effect is used, so that the mechanical strength (bending, pulling, etc.) of the electrode foil decreases, and There are drawbacks such as breakage of the foil at the time of the rotation and cracking of the connection portion of the drawn-out tab terminal.

The inventor of the present invention has made intensive studies and studies, and as a result, has made the tab terminals of wide width into a plate shape, and sandwiched both of the tab terminals with an extremely thin insulating material. The tab terminals are closely attached so as to overlap, and the connection portion with the external terminal is bent horizontally, so that the draw-out tab terminal structure obtained has a very small annular portion, so that the inductance L of the terminal portion is reduced. It has been found that the impedance can be minimized in the relationship between the extraction positions of the two electrode tab terminals and the impedance characteristics.

In order to increase the number of lead-out tab terminals of the capacitor element, one in which both electrode tab terminals are overlapped is used.
When counted as a pair, it is possible to provide a plurality of locations on the end face of the capacitor element. However, if both electrode tab terminals are arranged at one location, the impedance can be minimized and the inductance L of the terminal section can be reduced. Has been found to be effective in reducing the

Accordingly, an object of the present invention is to reduce the impedance value, which is an electrical characteristic of a capacitor element, when the two electrode tab terminals are pulled out from the capacitor element, the point where the impedance value becomes minimum, that is, the two electrode tabs. An object of the present invention is to provide a terminal structure of a capacitor element in which a tab terminal is led out from a position where terminals overlap with each other, whereby the impedance value and the inductance L of the terminal portion can be easily reduced.

[0021]

Means for Solving the Problems To achieve the above object, the terminal structure of the capacitor element according to the present invention has a structure in which an anode foil and a cathode foil are respectively laminated on an electrode foil formed by appropriately interposing a separator. A capacitor element is formed by attaching and winding a tab terminal, and the tab terminal protruding from the capacitor element is coupled and fixed to conductive rivets protruding from the back surface of a sealing plate having external terminals on the surface. In the terminal structure of the capacitor element, a plurality of tab terminals are attached to the anode foil and the cathode foil so as to overlap with each other and to be separated by a predetermined distance,
When winding these electrode foils, the tab terminals are all arranged so as to be located on a straight line in the radial direction from the center of the winding, and the tab terminals projecting from the capacitor element are connected to the same-polarity tab terminals via an insulator. It is characterized by being joined to each other and fixedly connected to a conductive rivet.

In this case, the tab terminal attached to one of the electrode foils is formed wider and longer than the tab terminal attached to the other electrode foil, and an opening is provided substantially at the center thereof. The tab terminals attached to the other electrode foil may be joined to each other via a portion, and the tab terminals attached to the one electrode foil may be joined to each other at a tip portion thereof.

Also, the width and length of the tab terminals attached to the electrode foils are set to the same dimensions, and the tip ends of the tab terminals attached to the one electrode foil and the other end are attached to the other electrode foil. A configuration in which one end of each of the tab terminals is cut so as not to overlap with each other may be employed.

[0024]

Next, an embodiment of a terminal structure of a capacitor element according to the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1 FIGS. 1 and 2 show a schematic configuration of an embodiment of a terminal structure of a capacitor element according to the present invention.

First, in FIG. 1, reference numeral 20 denotes an anode foil and reference numeral 22 denotes a cathode foil, respectively, between the anode foil 20 and the cathode foil 22 and on the opposite side of the cathode foil 22 for holding an electrolyte. Arrange the separators 24 and 25,
The anode foil 20 and the cathode foil 22 are configured to be insulated and held when wound from one end.

A first tab terminal 20a and a second tab terminal 20b are mounted on the anode foil 20 with a predetermined space therebetween, and the tab terminals 20a, 20b are also mounted on the cathode foil 22.
Corresponding to the first tab terminal 22a and the second tab terminal 22
b.

In this case, the tab terminals 20 on the anode side are used.
On portions a and 20b, insulators 26 and 27 made of an insulating tube are applied to portions protruding above the anode foil 20, respectively. The tab terminals 22a and 22b on the cathode side are formed so as to protrude wider and longer than the tab terminals 20a and 20b on the anode side, and openings 23a and 23b are provided substantially at the centers thereof. , So that the corresponding tab terminals 20a and 20b on the anode side can be inserted.

Therefore, the anode foil 20 and the cathode foil 22 to which the tab terminals are attached are wound from one end thereof,
The first and second tab terminals 20a and 22a and the second and third tab terminals 20b and 22b are positioned on a straight line in the same radial direction from the center of the winding so that the capacitor element 30
[See FIGS. 2A and 2B].

FIG. 3 shows an embodiment of the connection structure of the capacitor element having the structure shown in FIGS. 1 and 2 to an external terminal. That is, in the present embodiment, the tab terminals 20a and 20b on the anode side on which the insulators 26 and 27 are respectively attached are replaced with the tab terminals 22a on the cathode side.
a and 22b are inserted through the bent openings 23a and 23b, and are joined to each of the same electrodes.

Thereafter, the anode side tab terminals 20a, 2a
0b and the cathode side tab terminals 22a, 22b
Are mounted on a pair of conductive rivets 32, 33 protruding from one side surface (back surface), respectively, and further, caulking washers 34, 35 are attached and fixed. External terminals 38 and 39 that are electrically connected to the rivets 32 and 33 are provided on the other side surface (front surface) of the sealing plate 36, respectively.

The capacitor element 30 thus formed is then sealed in a casing, subjected to a chemical treatment, and commercialized as an electrolytic capacitor.

Embodiment 2 FIGS. 4 and 5 show a schematic configuration of another embodiment of the terminal structure of the capacitor element according to the present invention.

In this embodiment, the structure is basically the same as that of the first embodiment shown in FIGS. 1 and 2, and the same components are denoted by the same reference numerals and detailed description thereof will not be repeated. That is, in the present embodiment, the tab terminals 20a and 20b on the anode side and the tab terminals 22a and 22b on the cathode side are used.
Are set to have the same width, and the tab terminals 20a ', 2a, 2a on the anode side are formed at the portions protruding upward from the anode foil 20 and the cathode foil 22, respectively.
0b 'cuts the right half, and connects each tab terminal 22 on the cathode side.
a 'and 22b' have a configuration in which the left half is cut [see FIGS. 5 (a) and 5 (b)].

In this embodiment, insulators 26 'and 27' made of an insulating film are provided so as to surround the respective tab terminals 20a 'and 20b' on the anode side.

The capacitor element 30 constructed as described above
Are insulators 26 'and 27', respectively, as shown in FIG.
Each of the tab terminals 20a and 20b on the anode side and the tab terminals 22a and 22b on the cathode side, which are coated in the opposite directions, are bent in the opposite directions and joined to the same electrode, respectively. Similarly, it can be mounted on a pair of conductive rivets 32, 33 protrudingly arranged on one side surface of the sealing plate 36, respectively, and further can be attached and fixed by attaching caulking washers 34, 35.

Embodiment 3 FIGS. 7 and 8 show a modification of the terminal structure of the capacitor element of Embodiment 1 shown in FIGS. 1 and 2 described above. Therefore, the same components are denoted by the same reference numerals, and detailed description is omitted.

That is, in this embodiment, the anode foil 20
The configuration of the tab terminals 20a, 20b and 22a, 22b respectively attached to the cathode foil 22 is exactly the same. In the present embodiment, the tab terminals 20a,
As an insulator attached to Ob, insulating films 26 ', 26 ", and 27' are interposed between tab terminals 20a, 22a, 20b, and 22b located on a straight line in the radial direction. , These insulating films 26 ', 2
Openings 26a ', 26', 27 'are formed substantially in the center of the openings 26a, 20b so that the tab terminals 20a, 20b on the anode side can make conductive contact.
26a "and 27a 'are provided [see FIGS. 8A and 8B].

The capacitor element 30 thus configured
As shown in FIG. 9, each of the tab terminals 20a, 22a, 2
It is configured such that Ob and 22b can be attached to the conductive rivets 32 and 33 of the sealing plate 26 without bending. That is, the anode side tab terminals 20a, 20b are connected to the openings 23a, 23b of the cathode side tab terminals 22a, 22b and the openings 26a ', 26 of the insulators 26', 26 ", 27 '.
a ", 27a ', and the cathode side tab terminals 22a, 22b are electrically connected to each other at the tip end thereof. The tab terminals 22a, 22b protrude from one side surface (back surface) of the sealing plate 36. The rivets 32 and 33 are attached to the pair of conductive rivets 32 and 33, respectively, and furthermore, the caulking washers 34 and 35 are attached and fixed together. External terminals 38 and 39 which are electrically connected are provided.

Embodiment 4 FIG. 10 shows still another modification of the terminal structure of the capacitor element of Embodiment 1 shown in FIGS. 1 and 2 described above.

That is, in the present embodiment, FIG.
In the same manner as in the embodiment shown in FIG. 7, the tab terminals 20a, 22a, 20b, 22b of the capacitor element 30 can be mounted on the conductive rivets 32, 33 of the sealing plate 26 without bending. Things.

Therefore, in the present embodiment, the anode side tab terminals 20a and 20b are conductively connected to each other through the openings 23a and 23b of the cathode side tab terminals 22a and 22b, and the cathode side tab terminals 22a and 22b are connected to each other. They are electrically connected to each other at their tips. Then, they are mounted on a pair of conductive rivets 32, 33 protrudingly arranged on one side surface of the sealing plate 36, respectively, and furthermore, caulking washers 34, 35 are attached and fixed.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, two or more tab terminals attached to each electrode foil can be set. Various other design changes can be made without departing from the spirit of the present invention.

[0044]

As described above, according to the terminal structure of the capacitor element according to the present invention, the electrode foil formed by laminating the anode foil and the cathode foil with an appropriate separator interposed therebetween is used.
Each of the tab terminals is attached and wound to form a capacitor element, and the tab terminals protruding from the capacitor element are respectively coupled to conductive rivets protruding from the back surface of a sealing plate having external terminals on the surface. In the terminal structure of the fixed capacitor element, a plurality of tab terminals are attached to the anode foil and the cathode foil so as to overlap and be separated from each other by a predetermined distance, and all of the tab terminals are wound when these electrode foils are wound. A configuration in which the tab terminals protruding from the capacitor element are joined to each other via the insulator and the same-polarity tab terminals are joined to each other via an insulator, and are fixed to the conductive rivet. By setting the tab terminal from the position where both electrode tab terminals overlap, which is the point where the impedance value becomes the smallest, Out it is possible to, yet also reducing the inductance L of the terminal portion with reduced the impedance value can be easily achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an electrode foil and terminals showing an embodiment of a lead terminal structure in a capacitor element according to the present invention.

2A is an external perspective view of the capacitor element after winding the electrode foil shown in FIG. 1, and FIG. 2B is a plan view of FIG.

FIG. 3 is an explanatory diagram showing a connection configuration of external terminals of the capacitor element shown in FIG.

FIG. 4 is a schematic configuration diagram of an electrode foil and a terminal showing another embodiment of a lead terminal structure in the capacitor element according to the present invention.

5A is an external perspective view of the capacitor element after winding the electrode foil shown in FIG. 4, and FIG. 5B is a plan view of FIG.

6 is an explanatory diagram showing a connection configuration of external terminals of the capacitor element shown in FIG.

FIG. 7 is a schematic configuration diagram of an electrode foil and a terminal showing a modification of the lead terminal structure in the capacitor element shown in FIG. 1;

8A is an external perspective view of the capacitor element after winding the electrode foil shown in FIG. 7, and FIG. 8B is a plan view of FIG.

9 is an explanatory diagram showing a connection configuration of external terminals of the capacitor element shown in FIG.

FIG. 10 is an explanatory diagram showing a modification of the connection configuration of the external terminals in the lead terminal structure of the capacitor element shown in FIGS. 1 and 2.

FIG. 11 is a characteristic curve diagram showing frequency characteristics of the electrolytic capacitor.

12 (a) to 12 (c) are explanatory views showing different lead terminal positions with respect to an anode foil and a cathode foil in a conventional electrolytic capacitor.

FIG. 13 is an explanatory diagram showing a plurality of lead terminal positions with respect to an anode foil and a cathode foil in a conventional electrolytic capacitor.

FIG. 14 is an external perspective view of a capacitor element after winding an anode foil and a cathode foil in a conventional electrolytic capacitor.

FIG. 15 is an explanatory diagram showing positions of lead terminals of the capacitor element shown in FIG. 14 with respect to the anode foil and the cathode foil.

FIG. 16 is an explanatory diagram schematically showing positions of the lead terminals with respect to the anode foil and the cathode foil of the capacitor element having a large number of lead terminals.

17 is an external perspective view of the capacitor element after winding the anode foil and the cathode foil shown in FIG. 16;

FIG. 18 is an explanatory diagram showing the relationship between the extraction positions of both electrode tab terminals and the impedance and equivalent series resistance in a relatively large capacitor.

19 is a characteristic diagram showing frequency characteristics of the impedance and the equivalent series resistance shown in FIG.

[Explanation of symbols]

 Reference Signs 20 anode foil 20a, 20a 'first extraction tab terminal 20b, 20b' second extraction tab terminal 22 cathode foil 22a, 22a 'first extraction tab terminal 22b, 22b' second extraction tab terminal 23a, 23b opening Parts 24, 25 Separator 26, 27 Insulator (insulating tube) 26 ', 26 ", 27' Insulator (insulating film) 26a ', 26a", 27a' Opening 30 Capacitor element 32, 33 Conductive rivet 34, 35 Caulking Washer 36 Sealing plate 38, 39 External terminal

Claims (3)

[Claims] 1. A capacitor element is formed by attaching a tab terminal to an electrode foil formed by laminating an anode foil and a cathode foil with an appropriate separator interposed therebetween and winding the tab terminal, and protruding from the capacitor element. In the terminal structure of the capacitor element in which the tab terminals are fixed to conductive rivets protruding from the back surface of the sealing plate provided with external terminals on the front surface, the anode foil and the cathode foil overlap with each other. At the same time, a plurality of tab terminals are attached at predetermined intervals, and when winding these electrode foils, all of the tab terminals are arranged in a straight line in the radial direction from the winding center, and the tab terminals protruding from the capacitor element Characterized in that the tab terminals of the same polarity are joined to each other via an insulator, and are connected and fixed to a conductive rivet. Terminal structure of. 2. The tab terminal attached to one of the electrode foils is formed wider and longer than the tab terminal attached to the other electrode foil, and an opening is provided substantially at the center thereof. 2. The capacitor according to claim 1, wherein the tab terminals attached to the other electrode foil are joined to each other via a via, and the tab terminals attached to the one electrode foil are joined to each other at a tip end thereof. Element terminal structure. 3. The tab terminal attached to the electrode foil is set to have the same width and length, and the tip of the tab terminal attached to the one electrode foil and the tab attached to the other electrode foil. 2. The terminal structure of a capacitor element according to claim 1, wherein the terminal has a configuration in which one end is cut so as not to overlap with each other.