JP3697594B2 - Low inductance capacitor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a low inductance capacitor.
[0002]
[Prior art]
FIG. 7A is a schematic side view showing a conventional capacitor. In this capacitor, capacitor elements 21 having electrode lead portions 22a and 22b at both ends are arranged in parallel, and the electrode lead portions 22a and 22b are connected to external connection terminals 25a and 25b by a current inflow portion 23a and a current outflow portion 23b. It is a thing. In the conventional capacitor, a relatively large capacitor can be easily and stably manufactured by connecting a plurality of relatively small capacitor elements 21 in parallel.
[0003]
[Problems to be solved by the invention]
By the way, in the capacitor of the conventional example, as indicated by an arrow in FIG. 7A, the current flowing from one external connection terminal 25a flows downward through the current inflow portion 23a, while in each capacitor element 21. From the right to the left, then flows upward through the current outflow portion 23b and flows out from the other external connection terminal 25b.
[0004]
However, in the conventional capacitor, the current inflow portion 23 a and the current outflow portion 23 b are provided apart from each other by the distance between both ends of the capacitor element 21. For this reason, the amount of inductance cancellation generated between the current inflow portion 23a and the current outflow portion 23b is small, and thus the mutual inductance is large. In addition, since a current flows in the capacitor element 21 in a certain direction between the current inflow portion 23a and the current outflow portion 23b, the element inductance generated thereby cannot be ignored. Further, normally, the inductance of the terminal is added to this. That means
(Total inductance) = (Element inductance) + (Terminal inductance)
+ (Mutual inductance)
Therefore, the conventional capacitor has a problem that the total inductance is increased.
[0005]
On the other hand, FIG. 2B shows a conventional capacitor using a capacitor element 31 having a distance between both ends larger than that of the capacitor element 21. When the distance between both ends of the capacitor element 31 is increased in this way, the amount of cancellation of the inductance generated between the current inflow portion 23a and the current outflow portion 23b becomes smaller and the mutual inductance becomes even larger. Further, since the element inductance is increased by the length of the current flow path, the total inductance is further increased. Therefore, the capacitor according to the conventional example has a problem that the total inductance increases as the distance between both ends of the capacitor element increases.
[0006]
The present invention has been made to solve the above-mentioned conventional drawbacks, and its purpose is that the total inductance is much smaller than the conventional one, and that it is influenced by the distance between both ends of the capacitor element. There is no low inductance capacitor to provide.
[0007]
[Means for Solving the Problems]
Accordingly, in the low inductance capacitor according to the first aspect, the capacitor element 1 having the electrode lead portions 2a and 2b at both ends is arranged in parallel, and the capacitor element 1 is connected in parallel to connect each electrode lead portion 2a and 2b to the external connection terminal 5a. 5b, in the low-inductance capacitor, the current inflow portion 3a and the current outflow portion 3b connected to the external connection terminals 5a and 5b are arranged close to each other along the side surface of the capacitor element 1. In addition, connecting portions 6a and 6b are provided, and the connecting portions 6a and 6b connect the current inflow portion 3a or the current outflow portion 3b and the electrode lead-out portions 2a and 2b along the direction between both ends of the capacitor element 1. It is characterized by being connected.
[0008]
In the low inductance capacitor according to the first aspect, since the current inflow portion 3a and the current outflow portion 3b are arranged in close proximity to each other, the amount of inductance cancellation generated between the both 3a and 3b becomes large, and therefore, mutual Inductance is reduced. In addition, since a current flows through the connecting portions 6a and 6b in the direction opposite to that in the capacitor element 1, the element inductance is canceled and becomes small. Therefore, the total inductance can be reduced. In addition, since the distance between the current inflow portion 3a and the current outflow portion 3b is not affected by the size of the capacitor element 1, the total inductance is affected by the distance between both ends of the capacitor element 1. It can be avoided.
[0009]
The low-inductance capacitor according to claim 2 is characterized in that the current inflow portion 3a and the current outflow portion 3b are constituted by flat conductors 7a and 7b.
[0010]
In the low-inductance capacitor according to the second aspect, since the current density between the current inflow portion 3a and the current outflow portion 3b is reduced, the inductance generated in the current inflow portion 3a or the current outflow portion 3b itself can be reduced. The total inductance can be further reduced.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, specific embodiments of the low-inductance capacitor of the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a transparent perspective view showing the low inductance capacitor. This low-inductance capacitor is formed by stacking substantially cylindrical capacitor elements 1 having electrode lead portions 2a and 2b at both ends in three layers in the upper and lower directions to form one row, and arranging these in four rows. In the same figure, reference numerals 7a and 7b denote flat conductors formed by bending the copper plate 8 shown in FIG. Since the two flat conductors 7a and 7b have the same configuration, one of them will be described with reference to FIG. 2. The flat conductor 7a includes the external connection terminal 5a, the copper plate electrode 9a, the terminal connection plate 4a, and the connection piece. It consists of eleven. The copper plate electrodes 9a and 9b of the flat conductors 7a and 7b are arranged so as to be inserted between the first row and the second row of the capacitor element 1 and between the third row and the fourth row. The connecting pieces 11 are bent and connected to the electrode lead portions 2a and 2b of each capacitor element 1. The terminal connection plates 4a and 4b are arranged above the capacitor elements 1 in the second and third rows, and the plate-like external connection terminals 5a and 5b protruding upward from the terminal connection plates 4a and 4b are connected to each other. Arrange them so that they are close to each other. Further, the whole configured as described above is molded with the resin 10. 2 is a resin inflow hole. When resin molding is performed, the resin 10 flows in from the resin inflow hole 12, and the resin inflow hole 12 is filled with the resin 10 as a whole. The strength of the is increased.
[0013]
Next, the operation of the low inductance capacitor will be described. FIG. 3A is a schematic side view of the low inductance capacitor. The current flowing from the inflow side external connection terminal 5a flows downward through the copper plate electrode 9a of the flat conductor 7a. Thus, the copper plate electrode 9a functions as the current inflow portion 3a. The current flowing in as described above flows outward (to the right in the figure) so as to flow into the capacitor element 1 from the current inflow portion 3a. In other words, the copper plate electrode 9 a also functions as a connection portion 6 a that connects the current inflow portion 3 a and the electrode lead portion 2 a of the capacitor element 1 along the direction between both ends of the capacitor element 1. Next, the current flows in the capacitor element 1 from one electrode lead portion 2a of the capacitor element 1 to the other electrode lead portion 2b toward the left in FIG. The other electrode lead-out portion 2b flows into the outflow side flat conductor 7b provided in parallel with the inflow side flat conductor 7a. Further, this current flows in the copper plate electrode 9b of the flat conductor 7b to the right in the figure through the portion that functions as the connecting portion 6b, and then flows upward through the portion that functions as the current outflow portion 3b. It flows out from the external connection terminal 5b on the outflow side.
[0014]
In the low inductance capacitor as described above, the current inflow portion 3a in which the current flows downward and the current outflow portion 3b in which the same amount of current flows upward are arranged close to each other. Therefore, the inductances generated by the current inflow portion 3a and the current outflow portion 3b are canceled each other, so that the mutual inductance is small. In addition, since a current in the direction opposite to the current flowing through the capacitor element 1 flows through the connection portions 6a and 6b, most of the element inductance of the capacitor element 1 is canceled. Further, since the copper plate electrodes 9a and 9b are formed in a flat plate shape, the current density is reduced, and the inductance generated in the current inflow portion 3a or the current outflow portion 3b is also small. In addition, since the external connection terminals 5a and 5b are also formed in a flat plate shape and are arranged close to each other so as to face each other, the terminal inductance is also reduced. Therefore, from the above, the low inductance capacitor has a very small total inductance, and an ideal performance as a capacitor can be obtained. In addition, since only the flat conductors 7a and 7b formed by bending one copper plate 8 are provided, the configuration can be made very simple.
[0015]
FIG. 3B shows a capacitor element 1 having a different distance between both ends in comparison with FIG. 3A. However, mutual inductance and terminal inductance are reduced by the opposing arrangement of the plate conductors 7a and 7b. The effect and the effect of reducing the element inductance by the connecting portions 6a and 6b can be obtained similarly in both cases shown in both figures. Therefore, the total inductance is hardly influenced by the distance between both ends of the capacitor element 1.
[0016]
4 and 5 are transparent perspective views showing other embodiments of the low-inductance capacitor of the present invention. In this low-inductance capacitor, the capacitor elements 1 arranged as shown in FIG. 1 are further arranged in parallel in the terminal-to-terminal direction, and the capacitor elements 1 are connected in parallel. Correspondingly, the plate electrodes 7a and 7b are also divided into current inflow sides 17a and 17b and current outflow sides 18a and 18b, respectively.
[0017]
Even in the low-inductance capacitors of other embodiments configured as described above, the mutual inductance and terminal inductance are reduced by the opposing arrangement of the plate conductors 17a, 17b, 18a, and 18b, and the element inductance is reduced by the connecting portions 6a and 6b. The effect of further reducing the current density by making the current flow path into a flat plate shape and thereby reducing the inductance can be obtained as in the case of the low inductance capacitor shown in FIG. Therefore, the total inductance of both is almost the same. On the other hand, since the capacity of the low-inductance capacitor shown in FIG. 4 is doubled, a high-performance low-inductance capacitor can be easily obtained in this way. This idea can be extended to apply the present invention to a low-inductance capacitor in which a large amount of capacitor elements 1 are arranged in parallel.
[0018]
Although specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. For example, FIG. 6 shows a modification of the external connection terminals 5a and 5b. FIG. 6 (a) shows a case where this is a convex terminal, and FIG. 6 (b) shows a case where it is a concave terminal. As shown in both figures, the external connection terminals 5a and 5b are basically flat plates opposed to each other, but only the tip portion thereof is deformed into a convex shape or a concave shape, thereby sufficiently reducing the terminal inductance. Thus, connection work such as external wiring can be facilitated. Moreover, in the said embodiment, although the arranged capacitor | condenser element 1 was molded with resin 10, this may be accommodated in a case and you may make it fill with insulating oil, insulating gas, resin, etc. FIG.
[0019]
【The invention's effect】
In the low inductance capacitor according to the first aspect of the present invention, since the current inflow portion and the current outflow portion are arranged in close proximity to each other, the amount of cancellation of inductance generated between the two becomes large, and thus the mutual inductance becomes small. Further, since a current flows through the connection portion in the direction opposite to the capacitor element, the element inductance is canceled and becomes smaller. Therefore, the total inductance can be reduced. In addition, since the distance between the current inflow portion and the current outflow portion is not affected by the size of the capacitor element, it is possible to avoid the influence of the total inductance due to the distance between both ends of the capacitor element. It becomes possible.
[0020]
In the low-inductance capacitor according to the second aspect, since the current density between the current inflow portion and the current outflow portion is small, the inductance generated in the current inflow portion or the current outflow portion itself can be reduced, so that the total inductance is further increased. It can be made smaller.
[Brief description of the drawings]
FIG. 1 is a transparent perspective view of a low inductance capacitor according to an embodiment of the present invention.
FIG. 2 is a plan view of a copper plate used in the low inductance capacitor.
FIG. 3 is a schematic side view of the low-inductance capacitor.
FIG. 4 is a transparent perspective view of a low inductance capacitor according to another embodiment of the present invention.
FIG. 5 is a schematic side view of the low-inductance capacitor.
FIG. 6 is a modification of the external connection terminal.
FIG. 7 is a schematic side view of a conventional capacitor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Capacitor element 2a Electrode extraction part 2b Electrode extraction part 3a Current inflow part 3b Current outflow part 5a External connection terminal 5b External connection terminal 6a Connection part 6b Connection part 7a Flat conductor 7b Flat conductor

Claims (2)

Capacitor elements (1) having electrode lead portions (2a) and (2b) at both ends are arranged in parallel, and each capacitor element (1) is connected in parallel to connect each electrode lead portion (2a) (2b) to an external connection terminal ( In the low inductance capacitor connected to 5a) and 5b, the current inflow portion (3a) and the current outflow portion (3b) connected to the external connection terminals (5a) and (5b) are connected to the capacitor element (1 ) Along the side surface of each other and provided with connecting portions (6a) and (6b), and the connecting portions (6a) and (6b) provide the current inflow portion (3a) or current outflow portion (3b). And the electrode lead-out portions (2a) and (2b) are connected along the direction between both ends of the capacitor element (1). The low-inductance capacitor according to claim 1, wherein the current inflow portion (3a) and the current outflow portion (3b) are constituted by flat conductors (7a) (7b).

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