JP5061693B2 - Case mold type capacitor - Google Patents

Description

  INDUSTRIAL APPLICABILITY The present invention is used in various electronic equipment, electrical equipment, industrial equipment, automobiles, and the like. The present invention relates to a molded case mold type capacitor.

  In recent years, from the viewpoint of environmental protection, all electric devices are controlled by inverter circuits, and energy saving and high efficiency are being promoted. In particular, in the automobile industry, hybrid vehicles (hereinafter referred to as HEVs) that run on electric motors and engines have been introduced into the market, and the development of technologies relating to energy saving and high efficiency has been activated, which is friendly to the global environment.

  Since such a HEV electric motor has a high operating voltage range of several hundred volts, a metallized film capacitor having high withstand voltage and low loss electric characteristics as a capacitor used in connection with such an electric motor. In addition, the trend of adopting metalized film capacitors with a very long life is conspicuous due to the demand for maintenance-free in the market.

  And since the metallized film capacitor used for HEVs in this way is required to have a high withstand voltage, large current, large capacity, etc., a plurality of metallized films connected in parallel by bus bars. A case mold type capacitor in which a capacitor is housed in a case and a mold resin is poured into the case has been developed and put into practical use.

  FIG. 8 is an exploded perspective view showing the structure of this type of conventional case mold type capacitor. In FIG. 8, 10 indicates a metallized film capacitor (hereinafter referred to as a capacitor), and the capacitor 10 is made of polypropylene. A pair of metallized films with metal-deposited electrodes formed on one or both sides of a dielectric film are wound in a state where the metal-deposited electrodes face each other with a dielectric film between them, and metallized electrodes are sprayed on both ends to form a metallized electrode By doing so, a pair of extraction electrodes of P and N poles are provided.

  Reference numeral 11 denotes a P-pole bus bar, and 11a denotes a P-pole terminal for external connection provided at one end of the P-pole bus bar 11. The P-pole bus bar 11 includes a plurality of capacitors 10 in close contact with each other. The P electrode 10 is joined to a P electrode formed on one end face, and the P electrode terminal 11a is pulled out above the capacitor 10 and exposed from a case 13 described later.

  Reference numeral 12 denotes an N-pole bus bar, and 12a denotes an N-pole terminal for external connection provided at one end of the N-pole bus bar 12. The N-pole bus bar 12 also includes a plurality of capacitors 10 in the same manner as the P-pole bus bar 11. The N pole electrodes formed on the other end face of each capacitor 10 are joined together in close contact, and the N pole terminal 12a is pulled out above the capacitor 10 and exposed from a case 13 described later. Thus, a plurality of capacitors 10 are connected in parallel connection by the P-pole bus bar 11 and the N-pole bus bar 12.

  Reference numeral 13 denotes a resin case, and reference numeral 14 denotes a mold resin filled in the case 13. The mold resin 14 is connected in parallel by the P-pole bus bar 11 and the N-pole bus bar 12. Is resin-molded in the case 13.

  FIG. 9 is a simplified diagram for easy understanding of a configuration in which the plurality of capacitors 10 are connected by connecting them together by the P-pole bus bar 11 and the N-pole bus bar 12. As shown in FIG. 2, a P pole bus bar 11 having a P pole terminal 11a for external connection at one end is provided with a plurality of junctions 11b branched in branches, and the P of the capacitor 10 is connected via the junctions 11b. It is joined to the electrode electrode (upper surface side in FIG. 8) by the soldering part 11c.

  In addition, the N-pole bus bar 12 on the bottom side in FIG. 9 has a branch-like joint 12b (not shown) similar to the branch-like joint 11b provided on the P-pole bus bar 11 on the top side in the vertical direction. A plurality of symmetrically provided parts are similarly joined by a soldering part 12c (not shown) via these branch-like joining parts 12b (not shown). By molding the capacitor 10 in the case 13 with the mold resin 14, a highly reliable case mold type capacitor excellent in mechanical strength, heat resistance, and water resistance can be provided.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2004-146724 A

  However, in the conventional case mold type capacitor, when a current is applied to the case mold type capacitor via an external device (not shown), the P pole electrode and the P pole bus bar 11 provided on both end faces of the capacitor 10 are provided. The heat generated in the vicinity of the soldered part 11c joined to the joined part 11b and the soldered part 12c joined to the joined part 12b provided on the N pole electrode and the N pole bus bar 12 in a straight line. The heat generation in the portion other than the vicinity where the soldering portions 11c and 12c are connected by a straight line is larger, and the heat generation of the capacitor 10 closest to the P-pole terminal 11a and the N-pole terminal 12a is larger than the heat generation of other capacitors. There is a problem that it tends to be large, which tends to cause characteristic deterioration.

  Such a problem is that the current input through the P-pole terminal 11a, the P-pole bus bar 11 and the soldering portion 11c is as follows when the current has a fundamental frequency of several kHz to several tens of kHz, which is often used in normal inverter switching. It propagates to the entire P pole electrode of the capacitor 10, passes through the inside of the capacitor 10 substantially uniformly and propagates to the entire N pole electrode, and then flows to the N pole bus bar 12 via the soldering portion 12c. When an external device (not shown) connected to a simple case mold type capacitor performs a switching operation at the fundamental frequency, it is remarkable when a high-frequency current of 100 kHz to several hundred kHz flows due to resonance with harmonics or other electronic components. It appears in

  The flow of current in the capacitor 10 when such a high-frequency current that greatly exceeds the fundamental frequency flows is because the soldering part 11c and the soldering part 12c are provided in a vertically symmetrical position on a straight line. Even in the capacitor element, due to the skin effect, current flows only in the vicinity of the straight line connecting the soldering portion 11c and the soldering portion 12c, and thus the straight line connecting the soldering portions 11c and 12c. Only near the periphery generates significant heat.

  Further, when a high-frequency current that greatly exceeds the fundamental frequency flows, even if a plurality of capacitors 10 are connected in parallel, it is closest to the P-pole terminal 11a and the N-pole terminal 12a and has a small inductance. Since current flows concentrated on the capacitor 10, the heat generation of the capacitor 10 adjacent to the P-pole terminal 11a and the N-pole terminal 12a may be further increased.

  Moreover, when such a phenomenon was confirmed in detail, it was found that the skin effect was strong when a high-frequency current of 100 kHz or higher was observed, and that when viewed as a single element, the influence of heat generation was different depending on the soldering location to the metallicon electrode. It was. Furthermore, the influence has also confirmed that the element nearest to the P pole terminal 11a and the N pole terminal 12a connected with an external apparatus is especially easy to be influenced.

  The present invention solves such a conventional problem, and even when a high-frequency current that greatly exceeds the fundamental frequency flows, only a specific part of the capacitor generates heat locally or only a capacitor close to the external terminal It is an object of the present invention to provide a case mold type capacitor that suppresses high heat generation, exhibits excellent heat resistance, and can be adapted to high-frequency currents.

In order to solve the above-described problems, the present invention connects a plurality of flat elements each having a P-pole electrode and an N-pole electrode on both end faces by a bus bar having a terminal for external connection at one end. In a case-molded capacitor that is housed in a case and resin-molded except for at least the terminals provided on the bus bar, the P-pole electrode and the bus bar in each element are connected to a plurality of soldered portions branched from the bus bar. A plurality of soldering portions of the P-pole electrode and the bus bar are all arranged on one half surface in the major axis direction on the end face provided with the P-pole electrode, and the N-pole electrode in each element The bus bar is connected by a plurality of soldered portions branched from the bus bar, and the plurality of soldered portions with the bus bar of the N-pole electrode are on the end surface on which the N-pole electrode is provided. The plurality of soldered portions of the P-electrode electrode bus bar and the N-electrode bus bar are inclined with respect to the winding axis of the element. The one side half surface on the end face provided with a plurality of soldered portions with the bus bar of the P-pole electrode and the end face on the end surface provided with the plurality of soldered portions with the bus bar of the N-pole electrode. The half surface on one side is configured to be positioned diagonally in a side view of the element .

As described above, the case mold type capacitor according to the present invention has a fundamental frequency with a configuration in which the soldered portion of the P-pole electrode and the soldered portion of the N-pole electrode in each element are located diagonally in the side view of the element. Even when a high-frequency current that greatly exceeds the current flows, the current flows more uniformly in the element than when the soldering portion is provided at the symmetrical position, and the effect of avoiding concentration of heat generation can be obtained.

  This is because an electric current flows from the soldered portion formed on one metallicon electrode to the soldered portion formed on the other metallicon electrode. The current flows into the metal deposition electrode after a wide current flows in the direction of the soldered portion on the other metallicon electrode surface, thereby suppressing the phenomenon that the current is locally concentrated in the element and the heat generation is increased. This effect can be obtained. By applying this effect to an element in the vicinity of the P-pole / N-pole terminal where high-frequency currents are likely to concentrate, a greater effect can be obtained.

(Embodiment 1)
Hereinafter, the invention described in the entire claims of the present invention will be described using the first embodiment.

  1 is a perspective view before resin molding showing a configuration of a case mold type capacitor according to Embodiment 1 of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is an exploded perspective view of FIG. 3, reference numeral 1 denotes a metallized film capacitor (hereinafter referred to as a capacitor). The capacitor 1 is a pair of metallized films each having a metal-deposited electrode formed on one or both sides of a dielectric film made of polypropylene. The metal vapor-deposited electrodes are wound in a state of being opposed to each other through a dielectric film, and a metallicon electrode sprayed with zinc is formed on both end surfaces, respectively, thereby forming a P-electrode (upper surface in FIG. 1) and an N-electrode (see FIG. 1). 1 is provided with a pair of extraction electrodes on the bottom surface side, and two capacitors 1 each configured as described above are provided in two rows (in addition, a capacitor is provided). The number of capacitors 1 are not limited to).

  2 is a P pole bus bar, 2a is a P pole terminal for external connection provided at one end of the P pole bus bar 2 and drawn upward, and 2b is branched from the P pole bus bar 2 into a plurality of branches and soldered This is a joint portion soldered to the P-electrode of each capacitor 1 at the portion 2c.

  3 is an N pole bus bar, 3a is an N pole terminal for external connection provided at one end of the N pole bus bar 3 and drawn upward, and 3b is branched from the N pole bus bar 3 into a plurality of branches and soldered. The joint 3b is soldered to the N-pole electrode of each capacitor 1, and the joint 3b and the soldering part 3c are connected to the joint 2b and the soldering part 2c provided on the P-pole bus bar 2 in the vertical direction. It is provided so as to be asymmetrical in the direction, that is, connected by a line inclined with respect to the winding axis of the capacitor 1.

  Then, after accommodating a plurality of capacitors 1 integrally connected by the P-pole bus bar 2 and the N-pole bus bar 3 in a case (not shown), the case is filled with an insulating mold resin (not shown). A case mold type capacitor according to the present embodiment is constructed, and is connected to an external device (not shown) via the P-pole terminal 2a and the N-pole terminal 3a exposed from the mold resin (not shown).

  In the present embodiment, a polypropylene film having a thickness of 3 μm is used as the dielectric film. Further, the capacitor 1 has a capacitance of 100 μF, and since the four capacitors 1 are connected in parallel, the capacitor 1 is a 400 μF capacitor.

  The case mold type capacitor according to the present embodiment configured as described above has a configuration in which the P electrode electrode soldering portion 2c and the N electrode electrode soldering portion 3c of each capacitor 1 are in an asymmetric position. Even when a high-frequency current that greatly exceeds the fundamental frequency flows, the soldering portion 2c of the P-pole electrode of each capacitor 1 is on the metal electrode surface of the P-pole electrode, compared with the case where the soldering portion is provided at the symmetrical position. Since the current easily flows in the direction of the soldering portion 3c of the N-pole electrode on the opposite side, the current also flows widely in the wound metallized film. Even when viewed from the soldering portion 3c on the metallicon surface of the N-electrode, a current flows widely in the element by the same mechanism.

  When this current flows, the soldering portion 2c and the soldering portion 3c are connected by a line inclined with respect to the winding axis of the capacitor 1, so that even if there is an influence of the skin effect, the inside of the capacitor 1 As a result, the current flows in many parts of the wire, which can suppress the phenomenon that the current is concentrated only in the vicinity of the vicinity of the straight line connecting the soldering portions 2c and 3c and the heat generation is increased. It plays.

  Furthermore, such an effect also has an exceptional effect of suppressing the phenomenon that the heat generation of the capacitor 1 in the vicinity of the P-pole terminal 2a and the N-pole terminal 3a is increased, and has excellent heat resistance and high frequency current. It is possible to realize a case mold type capacitor that can be adapted.

  The results of evaluating the heat resistance of the case mold capacitor according to the present embodiment configured as described above are shown in Table 1 in comparison with a conventional product as a comparative example.

  In addition, as an evaluation method, the temperature rise of the center position (within the core) of the capacitor closest to the P-pole electrode when the 300 kHz sine wave ripple current 30 Arms is energized and the flat portion surface position are measured. The temperature at the center of the element was measured by inserting a thermocouple into the core of the element, and the temperature at the surface of the flat part was measured by attaching the thermocouple to the surface of the flat part of the element.

  Further, the configuration of the conventional product as a comparative example is manufactured in the same manner as in the first embodiment except that the soldering portion is provided at the symmetrical position, as shown in detail in the perspective view of FIG.

  In FIG. 7, 6 is a P pole bus bar, 6a is a P pole terminal for external connection provided at one end of the P pole bus bar 6 and drawn upward, and 6b is branched from the P pole bus bar 6 into a plurality of branches. Thus, the soldering portion 6c is a joint portion soldered to the P-pole electrode of each capacitor 1 respectively.

  7 is an N pole bus bar, 7a is an N pole terminal for external connection provided at one end of the N pole bus bar 7 and drawn upward, and 7b is branched from the N pole bus bar 7 into a plurality of branches and soldered. The joint 7b and the soldering part 7c are respectively connected to the joint 6b and the soldering part 6c provided on the P pole bus bar 6 in the vertical direction. It is provided so as to be symmetric with respect to the direction, that is, to be connected by a straight line with the shortest distance parallel to the winding axis of the capacitor 1.

  As is clear from Table 1, the case mold type capacitor according to the present embodiment has a configuration in which the soldered portion of the P-pole electrode and the soldered portion of the N-pole electrode in each element are in an asymmetric position. It can be seen that the temperature rise at the center of the element is 6K smaller than that of the comparative example, and the temperature difference from the flat portion surface is also small. This means that local heat generation at the center of the capacitor element can be reduced even with a high frequency current of 300 kHz.

  In the comparative example, since the soldering portion is in a symmetrical position, almost no current flows on the metallicon electrode surface due to the influence of the skin effect, and only in the periphery where the soldering portions 6c and 7c are connected by a straight line. Since the heat generation is extremely concentrated, the temperature rise at the element center of the capacitor located near the soldering portions 6c and 7c is higher than that in the first embodiment.

  In the present embodiment, the soldering position at the asymmetric position as shown in FIGS. 1 to 3 has been described as an example, but the present invention is not limited to this, and the winding axis of the element is used. On the other hand, if it is in an asymmetric position, the same effect can be exhibited.

Further, in the present embodiment, the description has been given by taking as an example two-point solder for soldering two points on one metallicon electrode surface, but the present invention is not limited to two points.

  Furthermore, in the present invention, it is effective to apply such a soldering position to an element close to the P pole / N pole terminal connected to an external device, in other words, from the P pole / N pole terminal. Since it is difficult for a high-frequency current to flow through a distant element, there is little influence even if the soldering position is not asymmetric. Therefore, when considering the yield of the material for producing the bus bar, the soldering portion is provided asymmetrically in the element close to the P-pole / N-pole terminal, and the soldering portion is placed in a symmetrical position in the element far from the P-pole / N-pole terminal. It is also possible to perform a combination as provided, which increases the cost effect.

(Embodiment 2)
Hereinafter, the second embodiment will be used to describe the invention described in the entire claims.

  In this embodiment, the configurations of the P-pole bus bar and the N-pole bus bar used in the case mold type capacitor described in the first embodiment with reference to FIGS. 1 to 3 are partially different. Since the configuration other than this is the same as that of the first embodiment, the same reference numerals are given to the same parts and the detailed description thereof is omitted, and only different parts will be described below with reference to the drawings.

  4 is a perspective view before resin molding showing the configuration of a case mold type capacitor according to Embodiment 2 of the present invention, FIG. 5 is a plan view of FIG. 4, and FIG. 6 is an exploded perspective view of FIG. In FIG. 6, reference numeral 1 denotes a capacitor formed in the same manner as in the first embodiment.

  4 is a P pole bus bar, 4a is a P pole terminal for external connection provided at one end of the P pole bus bar 4 and drawn upward, and 4b is branched from the P pole bus bar 4 into a plurality of branches and soldered. This is a joint portion that is soldered to the P-electrode of each capacitor 1 at the portion 4c.

  5 is an N pole bus bar, 5a is an N pole terminal for external connection provided at one end of the N pole bus bar 5 and drawn upward, and 5b is branched from the N pole bus bar 5 into a plurality of branches and soldered. The joint 5b is soldered to the N-pole electrode of each capacitor 1 at the portion 5c. The joint 5b and the soldering portion 5c are connected to the joint 4b and the soldering portion 4c provided on the P-pole bus bar 4 in the vertical direction. It is provided so as to be asymmetrical in the direction, that is, connected by a line inclined with respect to the winding axis of the capacitor 1.

  Then, after accommodating a plurality of capacitors 1 integrally connected by the P-pole bus bar 4 and the N-pole bus bar 5 in a case (not shown), an insulating mold resin (not shown) is filled in the case. A case mold type capacitor according to the present embodiment is constructed, and is connected to an external device (not shown) via the P-pole terminal 4a and the N-pole terminal 5a exposed from the mold resin (not shown).

  The results of evaluating the heat resistance of the case mold type capacitor according to the present embodiment configured as described above are described together with the above (Table 1).

  As is clear from Table 1, the case mold type capacitor according to the present embodiment has a configuration in which the soldered portion of the P-pole electrode and the soldered portion of the N-pole electrode in each element are in an asymmetric position. It can be seen that the temperature rise at the center of the element is 5K smaller than that of the comparative example, and the temperature difference from the flat portion surface is also small. This means that local heat generation at the center of the capacitor element can be reduced even with a high frequency current of 300 kHz.

  In the comparative example, since the soldering portion is in a symmetrical position, almost no current flows on the metallicon electrode surface due to the influence of the skin effect, and only in the periphery where the soldering portions 6c and 7c are connected by a straight line. Since the heat generation is extremely concentrated, the temperature rise at the element center of the capacitor located near the soldering portions 6c and 7c is higher than that in the first embodiment.

  The case mold type capacitor according to the present embodiment configured as described above is the same as the case mold type capacitor according to the first embodiment, even when a high frequency current greatly exceeding the fundamental frequency flows. After a current flows widely from the soldering part 4c of the P electrode of 1 on the metallicon electrode surface, the current is widely supplied into the wound metallized film, and the N electrode is passed through the metallized electrode surface on the N pole side. A current flows to the electrode soldering portion 5c. That is, when this current flows, since the soldering portion 4c and the soldering portion 5c are connected by a line inclined with respect to the winding axis of the capacitor 1, the current flows in many parts inside the capacitor 1. As a result, the phenomenon that current is concentrated only around the straight line connecting the soldered portions 4c and 5c and heat generation is increased, and the capacitor adjacent to the P-pole terminal 4a and the N-pole terminal 5a is suppressed. It is possible to realize a case mold type capacitor that has an excellent effect of suppressing the phenomenon that the heat generation of 1 is increased, has excellent heat resistance, and can be adapted to a high frequency current. is there.

  The case mold type capacitor according to the present invention does not generate high heat locally at a specific portion of the capacitor, or exhibits high heat resistance without generating high heat only at the capacitor close to the terminal for external connection. In particular, it is useful as a capacitor in the field of automobiles such as hybrid cars.

The perspective view before the resin mold which showed the structure of the case mold type capacitor | condenser by Embodiment 1 of this invention Plan view of FIG. 1 is an exploded perspective view of FIG. The perspective view before the resin mold which showed the structure of the case mold type capacitor by Embodiment 2 of this invention Plan view of FIG. 4 is an exploded perspective view of FIG. The perspective view before the resin mold which showed the composition of the case mold type capacitor by a comparative example An exploded perspective view showing a configuration of a conventional case mold type capacitor Plan view showing a simplified structure of a conventional case mold capacitor

Explanation of symbols

1 Capacitor 2, 4 P pole bus bar 2a, 4a P pole terminal 2b, 3b, 4b, 5b Junction part 2c, 3c, 4c, 5c Soldering part 3, 5 N pole bus bar 3a, 5a N pole terminal

Claims (1)

A plurality of flat elements each having a P-pole electrode and an N-pole electrode provided on both end faces are connected by a bus bar provided with a terminal for external connection at one end,
In a case mold type capacitor in which these are housed in a case and resin molded except at least the terminals provided on the bus bar,
The P pole electrode and the bus bar in each element are connected by a plurality of soldering portions branched from the bus bar in a branch shape, and the plurality of soldering portions with the bus bar of the P pole electrode have a P pole electrode. All are arranged on one half of the long axis direction on the provided end face,
The N pole electrode and the bus bar in each element are connected by a plurality of soldering portions branched from the bus bar in a branch shape, and the plurality of soldering portions with the bus bar of these N pole electrodes All are arranged on one half of the long axis direction on the provided end face,
The plurality of soldered portions with the P-pole electrode bus bar and the plurality of soldered portions with the N-pole electrode bus bar are connected by lines inclined with respect to the winding axis of the element,
The one-sided half surface on the end surface provided with a plurality of soldered portions with the P-pole electrode bus bar and the one-sided half surface on the end surface provided with the plurality of soldered portions with the N-pole electrode bus bar Case mold type capacitor located diagonally in view .

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