JP2000286150A - Capacitor aggregate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent lowering of an allowable current due to bias of ripple current by setting the ratio of length in a connection direction between terminals and width with respect to a connection direction in a metallic conductor to at least a specified value. SOLUTION: A capacitor aggregate 1 is formed, by connecting a same pole lead terminal 4 of each of a plurality of capacitors 2 of a relatively small diameter, arranged in parallel to a metallic plate 3 which is a metal conductor. In the capacitor 2, a capacitor element is stored inside a bottomed tubular aluminum exterior case, its open end part is sealed by a sealing member, and a lead terminal 4 is provided passing through the sealing member. The lead terminal 4 is connected to a capacitor element. In the metallic plate 3 connecting each of the capacitors 2, R=W/L where R is the ratio of width W to length L in a connection direction thereof, where the capacitors 2 are arranged in parallel and is made at least about 1/4, and the plate is formed wide. Thereby, a current flowing to each capacitor is made uniform, and allowable current of a capacitor aggregate is made high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor assembly formed by connecting a plurality of capacitors in parallel with conductors for the purpose of reducing the impedance of the capacitors more efficiently.

[0002]

2. Description of the Related Art Hitherto, as a method of lowering the impedance of an aluminum electrolytic capacitor at high frequencies, it has been practiced to increase the conductive area of the electrolytic solution by enlarging the metal foil area of the capacitor element. However, the metal foil used in these capacitor elements has a considerable electrical resistance. Even if the foil area is increased by elongating the length of the metal foil, if the winding diameter exceeds 16 mm, the area increases due to the resistance of the metal foil. Even if it does, the impedance does not decrease. For this reason, in the case of a relatively large capacitor having a winding diameter of the capacitor element exceeding 16 mm as described above, by increasing the number of terminals (tabs) from the element, the metal foil can be shortened without changing the total length of the foil. In each case, the influence of the resistance of the metal foil is reduced to reduce the impedance.
Dance is performed, but in this case, there is a limit due to an increase in tabs and difficulty in connecting the plurality of tabs, and there is a case where a sufficient decrease in impedance cannot be obtained.

For this reason, in the same manner as the above-described division of the metal foil into short units, each of these units is made into a small capacitor, and as shown in FIG. And a method of measuring impedance reduction at high frequencies by attaching the antennas in parallel on a conductor such as a metal plate 3 'or the like.

[0004]

However, when these small capacitors are mounted in parallel on a conductor such as a substrate or a metal plate to form a capacitor assembly, ripples flowing through all capacitors are connected to the capacitor closest to the input. 50 of current
There was a problem that more than% of them got on.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems, and is intended to prevent a decrease in allowable current due to the above-described deviation of ripple current and to provide a capacitor having a low high-frequency impedance as a whole. It is intended to provide an aggregate.

[0006]

In order to solve the above-mentioned problems, a capacitor assembly according to the present invention is a capacitor assembly formed by connecting and integrating the same pole terminals of a plurality of capacitors with a metal conductor. The ratio R = W / L of the length L of the metal conductor in the connection direction of the terminals to the width W of the metal conductor in the connection direction is １ ／ or more. According to this feature, the width W and length L of the metal conductor to which each capacitor is connected are 1 as described above.
By increasing the width to / 4 or more, the current flowing through each capacitor can be made uniform, and not only can the resulting allowable current of the entire capacitor assembly be increased, but also its high-frequency impedance can be increased. It can be low.

[0007] In the capacitor assembly of the present invention, it is preferable that the metal conductor is a metal plate, and the metal plate is bent and arranged. By doing so, the area occupied by the obtained capacitor assembly on the substrate can be reduced.

[0008] It is preferable that the capacitor assembly of the present invention is formed by bending the metal plate so as to be along the side of the capacitor arranged in parallel. With this configuration, not only the occupied area and occupied volume of the obtained capacitor assembly on the substrate can be reduced, but also the side of the capacitor is covered with the metal plate, which is protected from external force and heating during mounting. Become so.

It is preferable that the capacitor assembly of the present invention has a connection terminal formed at a substantially central portion in a connection direction of the metal conductor. By doing so, the distances to the connected capacitors can be made substantially equal, and the current flowing through the capacitors can be made more uniform.

[0010] It is preferable that the capacitor assembly of the present invention has connection terminals formed at both ends in the connection direction of the metal conductor. By doing so, the distance to each connected capacitor can be shortened, and the influence of the increase in impedance due to the resistance of the metal plate can be reduced.

The capacitor assembly of the present invention is preferably provided with an electrically insulating cover member that covers at least the metal conductor. This can prevent a short circuit or the like from occurring even if the metal conductor comes into contact with another mounted component.

Preferably, the capacitor assembly of the present invention has an insulating plate disposed between the metal conductors of the two electrodes. With this configuration, it is possible to prevent the metal conductors of the two electrodes from contacting or short-circuiting during mounting or the like.

[0013]

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

(Embodiment) FIG. 1 is an external perspective view showing a capacitor assembly of this embodiment.

As shown in FIG. 1, the capacitor assembly 1 of this embodiment has a plurality of parallel-connected capacitors having relatively small diameters each having the same pole lead terminal 4 having a metal plate 3 made of a metal conductor. Is formed.

The capacitor 2 used in this embodiment
Is a method in which a capacitor element is housed in a bottomed cylindrical aluminum outer case, an open end thereof is sealed with a sealing member, and a lead terminal 4 is provided through the sealing member. 4 is connected to the capacitor element.

The capacitor element used in the present embodiment is formed by winding a separator between an anode foil and a cathode foil made of a valve metal such as aluminum, and impregnated with an electrolyte. And a solid electrolytic capacitor element in which a solid manganese dioxide layer is formed as an electrolyte between an anode foil and a cathode foil made of a valve metal such as aluminum.

The ratio R = W / L of the length L of the metal plate 3 to which each of the capacitors 2 is connected and the width L of the metal plate 3 in the connection direction in which the capacitors 2 are connected is small if this is small. Because the resistance of the metal plate causes a large difference in the ripple current of the connected capacitor, the ratio may be increased to 1/4 or more to increase the width. However, if the width W is too large, Since the area occupied by the metal plate 3 on the mounting board becomes large, it is preferable that the ratio is 1/4 or more based on the viewpoint and the width is kept to a minimum necessary width.

As a material of the metal plate 3 as a metal conductor, a metal having a low specific resistance and being resistant to corrosion and the like is preferable. Examples of these metals include copper, silver, gold and nickel.
A simple substance such as iron or aluminum or an alloy of two or more kinds is exemplified. Further, the surface of the metal plate 3 may be coated with a highly corrosion-resistant noble metal or the like, or may be subjected to solder plating or the like. May be a metal foil laminated on the substrate surface,
In this embodiment, a copper plate having a thickness of 0.4 mm is used as the metal plate 3.

The metal plate 3 and the lead terminal 4 led out from the sealing end face of the capacitor are connected and integrated by ultrasonic welding or the like.

Further, the shape of the metal plate is not limited to a flat shape as shown in FIG. 1, but as shown in FIG.
The metal plate 3 'connected to each electrode may be bent and arranged along the opposite side surfaces of the capacitor 2, so that the width W of the metal plate 3'
Is preferable because the area occupied by the obtained capacitor assembly on the substrate can be reduced.

In FIG. 2, connection terminals 5 for connection to a substrate are formed near the center of the lower end of the bent metal plate 3 '. Forming is preferable because the distance deviation of each capacitor 2 to the lead terminal can be reduced. However, the present invention is not limited to this. As shown in FIG. 8A, it may be provided at both lower ends of the metal plate 3 '. In this case, the distance between the lead terminal 4 and the connection terminal 5 can be reduced, Not only the resistance can be reduced, but also the resistance between the lead terminal 4 of the capacitor 2 connected to the central portion of the metal plate 3 'farther from the connection terminal 5 has two conductive paths. The resistance starts to decrease from the A connection terminal 5 Te each re - de terminal 4
Can be reduced.

The outer shape of the metal plate 3 'is not only square as shown in FIGS. 1 and 2, but also as shown in FIG. 8 (b). 'May have a substantially fan-shaped lower end.

The capacitor assembly 1 obtained as described above is covered with the insulating cover member 11 so as to cover the upper portion thereof as shown in a capacitor assembly 1 'in FIG. A short circuit due to contact with the metal plate 3 'may be prevented.

As shown in FIG. 2, not only the metal plates 3 'of the respective poles are bent in opposite directions but also as shown in the sectional view of FIG. Metal plate 6 along the same side of capacitor 2
a and 6b may be bent. In this case, the insulating resin plate 7 is placed between the metal plates 6a and 6b in order to prevent a short circuit due to contact between the metal plates 6a and 6b of the two electrodes. It may be provided.

The bent shape of the metal plate may be bent like the metal plate 8 in FIG. 4 in order to make the capacitor assembly 1 self-standing and surface mountable.
The capacitor 2 may be bent like the metal plates 9a, 9b, 10a, and 10b in FIGS. 5 and 6 so that the capacitor 2 can be mounted horizontally.

Further, when the W dimension of the metal plate is increased, the metal plate may be bent like metal plates 12a and 12b as shown in FIG. 7 in order to absorb the increase in the W dimension. In such a case, the metal plates 12a and 12b may be in contact with each other so that the metal plates 12a and 12b do not come into contact with each other and short-circuit.
It is preferable to form an electrically insulating resin layer 13 on the surfaces of a and 12b by coating or the like.

In order to compare the characteristics of the capacitor assembly of this embodiment with those of the conventional capacitor assembly,
The capacitor assembly 1 shown in FIG. 1 has five capacitors 2 connected in series and the ratio R of the metal plate 3 is 1/4, and the ratio R of the metal plate 3 is 1 / 12 was prepared, and the current flowing through each capacitor when a frequency of 100 KHz and 6.5 A were applied from one end of the metal plate in the capacitor connecting direction was measured. The results are shown below.

[Table 1]

In the above results, the capacitor 1 is closest to the one end where the current is applied, and the capacitor 5 is the capacitor farthest to the one end where the current is applied. From this result, in the conventional capacitor assembly,
A large amount of current flows through the capacitor 1, and the difference from the capacitor 5 having the smallest flowing current becomes large. The allowable current value of the obtained capacitor assembly is determined by the current value of the capacitor 1. Thus, while the allowable current value is reduced, the product of the present embodiment does not have a large difference in the current flowing in each capacitor, and the current flows on average, so that the allowable current value of the obtained capacitor assembly is It turns out that becomes large.

FIGS. 9 and 10 show the results of measuring the relationship between the frequency change and the impedance and ESR of the comparative example and the present example.

From this result, it can be seen that the impedance and ESR values of the product of the present embodiment are greatly reduced in the high frequency region.

Although the present invention has been described with reference to the drawings, the present invention is not limited to these embodiments, and any changes or additions that do not depart from the gist of the present invention will be described. Needless to say, it is included in the invention.

[0033]

The present invention has the following effects.

(A) According to the first aspect of the present invention, the width W and the length L of the metal conductor to which each capacitor is connected are made as wide as 1/4 or more, so that the current flows through each capacitor. The current can be made uniform, so that not only the allowable current of the entire resulting capacitor assembly can be increased, but also the high-frequency impedance can be reduced.

(B) According to the second aspect of the invention, the area occupied by the obtained capacitor assembly on the substrate can be reduced.

(C) According to the third aspect of the present invention, not only the area and volume occupied by the obtained capacitor assembly on the substrate can be reduced, but also the side of the capacitor is covered by the metal plate, and the external force is reduced. And heating during mounting.

(D) According to the invention of claim 4, the distances to the connected capacitors can be made substantially equal, and the current flowing through the capacitors can be made more uniform.

(E) According to the fifth aspect of the invention, the distance to each connected capacitor can be shortened, and the influence of the increase in impedance due to the resistance of the metal plate can be reduced.

(F) According to the invention of claim 6, it is possible to prevent a short circuit or the like from occurring even if the metal conductor comes into contact with another mounted component.

(G) According to the seventh aspect of the invention, it is possible to prevent the metal conductors of the two electrodes from contacting or short-circuiting during mounting or the like.

[0041]

[Brief description of the drawings]

FIG. 1 is an external perspective view showing a capacitor assembly according to an embodiment of the present invention.

FIG. 2 is an external perspective view showing a capacitor assembly according to another embodiment of the present invention.

FIG. 3 is an external perspective view showing a capacitor assembly according to another embodiment of the present invention.

FIG. 4 is an external perspective view showing a capacitor assembly according to another embodiment of the present invention.

FIG. 5 is an external perspective view showing a capacitor assembly according to another embodiment of the present invention.

FIG. 6 is an external perspective view showing a capacitor assembly according to another embodiment of the present invention.

FIG. 7 is an external perspective view showing a capacitor assembly according to another embodiment of the present invention.

FIG. 8A is a diagram illustrating an example of another connection terminal position. (B) is a figure which shows the external shape of other metal plates.

FIG. 9 is a graph showing the relationship between the frequency and the impedance of the product of the present example and the product of the comparative example.

FIG. 10 shows the frequency and E in the product of this example and the product of the comparative example.
It is a graph which shows the relationship with SR.

FIG. 11 is an external perspective view showing a conventional capacitor assembly.

[Explanation of symbols]

 1, 1 'capacitor assembly 2 capacitor 3, 3' metal plate 4 lead terminal 5 connection terminal 6a, 6b metal plate 7 resin plate 8 metal plate 9a, 9b metal plate 10a, 10b metal plate 11 cover member 12a, 12b metal Board 13 resin layer

Claims (7)

[Claims] The same-polarity terminals of a plurality of capacitors are connected to each other.
In a capacitor assembly connected and integrated with a metal conductor, a ratio R = W / of a length L of the metal conductor in a connection direction of the terminals and a width W with respect to the connection direction.
L is 1/4 or more, The capacitor assembly characterized by the above-mentioned. 2. The capacitor assembly according to claim 1, wherein the metal conductor is a metal plate, and the metal plate is bent and arranged. 3. The method according to claim 2, wherein the bending of the metal plate is performed along side portions of the capacitors arranged in parallel.
3. The capacitor assembly according to 1. 4. The capacitor assembly according to claim 1, wherein a connection terminal is formed at a substantially central portion of the metal conductor in a connection direction. 5. The capacitor assembly according to claim 1, wherein connection terminals are formed at both ends of the metal conductor in a connection direction. 6. The capacitor assembly according to claim 1, further comprising an electrically insulating cover member covering at least the metal conductor. 7. The capacitor assembly according to claim 1, wherein an insulating plate is arranged between the metal conductors of the two electrodes.