JP2009188158A - Case mold type capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a case molded capacitor, which is used for an automobile or the like, to improve heat resistance. <P>SOLUTION: The case molded capacitor is constituted by connecting elements 1 and 2 having at least two functions in parallel by bus bars provided with terminals 3 and 5, and 4 and 6 for external connection each at one end, and storing them in a case 7. A slit type hollow portion 7a for forming a gap extending from an external bottom surface of the case 7 to an inner side thereof is provided on a bottom surface of the case 7 at the boundary part between the elements 1 and 2 having the different functions. Consequently, an air layer formed between the elements 1 and 2 having the different functions has large thermal resistance and then conduction of heat is reduced to suppress conduction of heat of the element 2 generating large heat to the adjacent element 1 generating small heat and then to reduce an influence thereof, thereby exhibiting superior heat resistance. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  INDUSTRIAL APPLICABILITY The present invention is used in various electronic equipment, electrical equipment, industrial equipment, automobiles, etc., and in particular, a metallized film capacitor that is optimal for smoothing, filtering, and snubbing of a motor drive inverter circuit of a hybrid car is accommodated in a case. And a resin-molded case mold type capacitor.

  In recent years, from the viewpoint of environmental protection, all electrical 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.

  4 is an exploded perspective view showing the structure of this type of conventional case mold type capacitor, FIG. 5 is a sectional view taken along the line AA of FIG. 4, and in FIGS. 4 and 5, 10 is a metallized film capacitor. This capacitor 10 is a pair of metallized films in which metal vapor-deposited electrodes are formed on one or both sides of a dielectric film made of polypropylene, and the metal vapor-deposited electrodes are opposed to each other with the dielectric film interposed therebetween. In this state, a pair of extraction electrodes of P and N poles are provided respectively by forming metallicon electrodes with zinc sprayed on both end faces.

  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 housed in the case 13 and resin molded.

  The conventional case mold type capacitor configured as described above is a highly reliable case mold having excellent mechanical strength, heat resistance, and water resistance because the capacitor 10 is resin-molded in the case 13 with the mold resin 14. Type capacitors could 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, when the above-mentioned conventional case mold type capacitor is used for HEV, the smooth ripple current to the DC power supply increases because it is used for the purpose of smoothing the AC component of the DC power supply. It has a problem that the temperature becomes high and the heat margin becomes low.

  In recent years, in order to smooth the AC components of DC power supplies having two different voltages for miniaturization and cost reduction, the inverter smoothing and filter capacitors are accommodated in one case, respectively. In this case, since the smooth ripple current for each DC power source of two types of capacitors having different functions is different, the heat of the higher heat generating capacitor is adjacent to the other. The heat generated in the capacitor interferes with the heat generated in the lower capacitor, and as a result, the heat generated in the capacitor with the higher heat is propagated to the capacitor with the lower heat generated, thereby increasing the heat generation. If the allowable ripple current is not lowered, there is a problem that the life of the capacitor may be shortened.

  The present invention solves such a conventional problem, and exhibits excellent heat resistance by suppressing the heat of the capacitor with higher heat generation from affecting the other adjacent heat generation of the lower capacitor. An object of the present invention is to provide a case mold type capacitor.

  In order to solve the above problems, the present invention provides a case mold in which at least two elements having different functions are connected in parallel by a bus bar having a terminal portion for external connection at one end, and these are housed in a case and resin molded. In the type capacitor, a hollow portion having a convex cross section is formed at the boundary portion between elements having different functions by providing a slit in the bottom surface of the case that extends from the bottom surface of the case to the inside of the case. .

  As described above, the case mold type capacitor according to the present invention has the above-described function by the configuration in which the slit-like depression for forming the void having the convex cross section is provided at the boundary between the elements having different functions. Air is interposed in the gap formed at the boundary between different elements, and since this air layer has a high thermal resistance, heat propagation is mitigated, so the element with higher heat generation It is possible to reduce the influence of the heat by suppressing the heat of the other adjacent to the other element to be transmitted to the lower element, and the effect of exhibiting excellent heat resistance can be obtained. .

(Embodiment)
Hereinafter, the invention described in the entire claims of the present invention will be described by using embodiments.

  FIG. 1 is a perspective view showing the configuration of a case mold type capacitor according to an embodiment of the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a perspective view showing a state of the case mold type capacitor before resin molding. is there.

  1 to 3, reference numeral 1 denotes a first metallized film capacitor having an oval cross section (hereinafter referred to as a first element 1), and 2 denotes a second metallized film capacitor having an oval cross section (hereinafter referred to as a second metallized film capacitor). The first element 1 (same as the second element 2) is a metallized film (not shown) in which a metal-deposited electrode is formed on one or both sides of a dielectric film made of polypropylene. ), A metallicon electrode having a cross-sectionally flattened shape by press working after the metal vapor-deposited electrodes face each other across a dielectric film, and zinc sprayed on both end faces (see FIG. (Not shown) are provided to provide a pair of extraction electrodes of a P-pole electrode and an N-pole electrode.

  The first element 1 and the second element 2 have different functions. In the present embodiment, the first element 1 is used for smoothing an inverter corresponding to a first DC power source (not shown). Although the same element corresponding to a second DC power source (not shown) is used as the second element 2, the present invention is not limited to this.

  3 is a P pole terminal for external connection provided at one end of a first P pole bus bar (not shown), and 4 is an N pole terminal for external connection provided on a first N pole bus bar (not shown). The pole terminal 3 and the N pole terminal 4 are connected to the first DC power source (not shown). In addition, these first P-pole bus bar and first N-pole bus bar have the first element 1 in the horizontal direction (not limited to the horizontal direction) in the major axis direction of the oval cross section. A P-electrode composed of a pair of metallicon electrodes provided on both end faces of the first element 1 in a state where a plurality (three in the present embodiment, but not limited thereto) are arranged in parallel. And N pole electrodes are joined by soldering.

  Reference numeral 5 denotes an external connection P-pole terminal provided at one end of a second P-pole bus bar (not shown), and reference numeral 6 denotes an external connection N-pole terminal provided to a second N-pole bus bar (not shown). The pole terminal 5 and the N pole terminal 6 are connected to the second DC power source (not shown). The second P-pole bus bar and the second N-pole bus bar have the second element 2 in which the major axis direction of the oval cross section is vertical (not limited to the vertical direction). P electrode composed of a pair of metallicon electrodes provided on both end faces of the second element 2 in a state where a plurality (two in the present embodiment, but not limited thereto) are arranged in parallel. And N pole electrodes are joined by soldering.

  7 is a case made of resin (in this embodiment, PPS (polyphenylene sulfite) is used, but is not limited to this) and has an open top surface, and 7a is from the outer bottom surface of the case 7 to the inside of the case 7. The recess 7a is provided so as to be located at the boundary between the first element 1 and the second element 2 having different functions. By providing the recess 7a, a boundary wall 7b is formed at the boundary between the first element 1 and the second element 2 arranged in the case 7, and the inside of the boundary wall 7b is a void having a convex cross section. It is intended to be a part. 7c is an attachment part.

  Reference numeral 8 denotes a mold resin filled in the case 7, and the mold resin 8 is provided at one end of each of the first P-pole bus bar and the first N-pole bus bar joined to the first element 1. P-pole terminal 3, N-pole terminal 4, second P-pole bus bar joined to second element 2, P-pole terminal 5 provided at one end of each second N-pole bus bar, N-pole terminal In a state where only 6 is exposed on the upper surface, the first P-pole bus bar, the first element 1 connected by the first N-pole bus bar, and the second P-pole bus bar and the second N-pole bus bar are connected. The formed second element 2 is housed in a case 7 and resin molded. In this embodiment, an epoxy resin is used as the mold resin 8.

  The case mold type capacitor according to the present embodiment configured as described above has a configuration in which a slit-like depression 7a is formed at the boundary between the first element 1 and the second element 2 having different functions. The hollow portion 7a has an air space with a convex cross section, and the air layer has a large thermal resistance, so that heat propagation is mitigated, so heat generation is high. It is possible to reduce the influence by suppressing the heat of the other element from propagating to the other adjacent heat generation element, and exhibit an exceptional effect that it can exhibit excellent heat resistance It is.

  More specifically, in the present embodiment, the DC power supply voltage applied to the second element 2 for the filter is lower than the first element 1 for the smoothing of the inverter circuit. , (Ambient temperature + Heat generation due to ripple current) Even if the allowable temperature value is set high, there is no problem with the capacitor life. As a result, the second element 2 for use in the filter has a smaller capacitor shape and a reduced capacitor capacity even when the ripple current increases. Therefore, in the case of smoothing and for the filter, the second element 2 for the filter generates more heat, and the heat of the second element 2 propagates to the adjacent first element 1 and the first element 1 There is a problem that heat generation is increased and the life of the first element 1 is shortened. Actually, when the case 7 is not provided with the depression 7a, the temperature rises by 3.5 deg due to the heat generation of the element 2 in addition to the heat generation temperature of the element 1, but the depression 7a according to the present embodiment. According to the above, the further temperature rise of the element 1 is only 1.6 deg, and it can be said that a capacitor having a small thermal margin has a great effect.

  For reference, the dimension (mm) of the case 7 is described as follows: length L; 244, width W1; 114, height H1; 55, depth H2 of the recess 7a; 35, upper end of the recess 7a. The width W2 of the hollow portion 7a is 1.5, and the width W3 of the lower end of the hollow portion 7a is 3.5. The depth H2 of the hollow portion 7a is the arrangement of the second element 2 with higher heat generation. Although it is considered that it should be about 2/3 or more of the height dimension in the state, the present invention is not limited to these.

  Further, in the present embodiment, the recess 7 a provided on the bottom surface of the case 7 is opposed to the case 7 in order to form a void having a convex cross section at the boundary between the elements 1 and 2 having different functions. Although described using an example of a slit shape penetrating between the side surfaces, the present invention is not limited to this, and a wall portion that is the same surface as the opposing side surfaces may be provided on each side surface. As a result, the mechanical strength of the case 7 can be improved.

  The case mold type capacitor according to the present invention has an effect of being able to exhibit excellent heat resistance, and is useful as a capacitor in the field of automobiles and the like that require particularly high reliability.

The perspective view which showed the structure of the case mold type capacitor by one embodiment of this invention Front view The perspective view which showed the state before resin molding of the same case mold type capacitor An exploded perspective view showing a configuration of a conventional case mold type capacitor Sectional drawing in the AA line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st element 2 2nd element 3, 5 P pole terminal 4, 6 N pole terminal 7 Case 7a Depression part 7b Boundary wall 7c Attachment part 8 Mold resin

Claims (4)

At least two elements having different functions for smoothing the AC components of at least two DC power sources having different voltages are connected in parallel by a bus bar having a terminal portion for external connection at one end, and these are accommodated in a case. In the case mold type capacitor which is resin-molded except at least the terminal part of the bus bar, by providing a recess in the case bottom surface in the shape of a slit from the case outer bottom surface to the inside of the case, the boundary portion between elements having different functions A case mold type capacitor with a cavity with a convex cross section. The opposing side surfaces of the case, which are both ends of the slit-like depressions provided on the bottom surface of the case in order to form a gap having a convex cross section at the boundary between elements having different functions, are flush with the opposing side surfaces. The case mold type capacitor according to claim 1, wherein a wall portion is provided. The case mold type capacitor according to claim 1, wherein at least two kinds of elements having different functions are used for smoothing an inverter and for a filter. 2. The case mold type capacitor according to claim 1, wherein at least two kinds of elements having different functions are formed in an oval cross section.

Images