JP2012069840A - Case mold type capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a case mold type capacitor which positively radiates the heat of a capacitor element, and has high heat resistance and excellent reliability.SOLUTION: In a case mold type capacitor 1, resin 13 is filled in a metallic case 12 for storing a capacitor element 2. The resin 13 contains filler, and the content of the filler to the resin 13 is gradually decreased from an inner bottom surface 12b toward an opening portion 12a of the metallic case 12. Namely, in the case mold type capacitor 1, a lot of the filler having high thermal conductivity is made to exist near a lower part (a bottom portion side) of the metallic case 12 having comparatively high heat dissipation, thereby positively radiating heat generated from the capacitor element 2 to the outside. Consequently, the heat resistance of the case mold type capacitor 1 is enhanced, and the reliability of the case mold type capacitor 1 can be improved.

Description

  INDUSTRIAL APPLICABILITY The present invention is used in various electronic devices, electrical devices, industrial devices, automobiles, etc., and in particular, a metallized film capacitor that is optimal for smoothing, filtering, and snubber for motor drive inverter circuits of hybrid vehicles is housed in a case. Further, the present invention relates to a case mold type capacitor in which this is molded with resin.

  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 an electric motor for HEV has a high operating voltage range of several hundred volts, a metalized film capacitor having high withstand voltage and low loss electric characteristics has attracted attention as a capacitor used in connection with the 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 a cross-sectional view showing the structure of a conventional case mold type capacitor 100 of this type. In FIG. 8, the capacitor element 101 is composed of two metallized films (e.g. A pair of metallicon electrodes 102 are formed on both end faces.

  A pair of bus bars 103 is connected to the metallicon electrode 102, and an external connection terminal portion 103 a is provided at one end of the bus bar 103 in a direction different from the connection portion with the metallicon electrode 102.

  Then, the capacitor element 101 to which the pair of bus bars 103 are connected is accommodated in a resin case 104 having an open top surface, and a mold resin 105 is filled in a gap between the capacitor element 101 and the inner wall of the resin case 104. The case mold type capacitor 100 in which the external connection terminal portion 103a provided at one end of the bus bar 103 is exposed to the outside is configured.

  The mold resin 105 covers the capacitor element 101 for the purpose of improving moisture resistance as a product, and not only can prevent the intrusion of humidity (moisture) from the surroundings. It also plays a role of realizing a strong housing by taking advantage of the characteristics of resin with strong strength and impact resistance.

  That is, the conventional case mold type capacitor 100 configured as described above has an improved moisture resistance as a product by accommodating the capacitor element 101 in the resin case 104 and filling the gap with the mold resin 105 to be cured. The mechanical strength and impact resistance can be improved.

  In addition, as prior art document information of the invention of this application, for example, Patent Document 1 and Patent Document 2 are cited.

JP 2000-58380 A JP 2000-323352 A

  Certainly, the above-mentioned conventional case mold type capacitors have a certain level of moisture resistance, mechanical strength, and impact resistance. However, in order to exhibit sufficient performance as a capacitor, even in harsh environments. There is a need for little deterioration in characteristics over a long period of time, and the conventional structure cannot sufficiently satisfy this requirement.

  In particular, capacitors used for automobiles are often exposed to high-temperature and high-humidity environments due to factors such as installation location. Therefore, in order to maintain the characteristics over a long period of time as a capacitor, it is extremely important to improve heat resistance or heat resistance by dissipating heat generated from the element to the outside.

  Further, when the case mold type capacitor is used for HEV, the smooth ripple current to the DC power supply becomes large because it is used for the purpose of smoothing the AC component of the DC power supply. For this reason, the calorific value of the element increases, and the HEV case mold type capacitor has a problem that the thermal margin is small. From this point of view, it is important to improve the heat dissipation of the element.

  As means for solving the heat dissipation of this element, a method of adding an inorganic filler to a mold resin is generally known. However, when a large amount of inorganic filler is added to obtain better heat dissipation, the viscosity of the mold resin increases, and the mold resin may not be sufficiently filled in the resin case.

  Accordingly, an object of the present invention is to provide a case mold type capacitor having excellent heat resistance and moisture resistance and excellent in reliability in which a resin resin is sufficiently filled in a resin case.

  In order to solve this problem, the case mold type capacitor of the present invention includes a capacitor element formed by winding or laminating a pair of metallized films in which a metal deposition electrode is formed on a dielectric film, and the capacitor element. A case-molded capacitor comprising a metal case of an upper surface opening type containing a resin and a resin filled in the metal case, wherein the resin contains a filler, and the content ratio of the filler with respect to the resin is the metal case It was set as the structure which decreases gradually toward the opening surface of the said metal case from the inner bottom face.

  According to the configuration of the present invention, the heat dissipation of the case mold type capacitor can be enhanced.

  This is because the heat generated from the capacitor element is transferred to the bottom of the metal case through the filler by making the filler having high thermal conductivity relatively large in the mold resin near the inner bottom surface of the metal case. By radiating heat from the bottom to the outside.

  That is, according to the present invention, in the case of a metal case having an open top surface, the heat generated from the capacitor element is actively conducted to the lower part (bottom side) having higher heat dissipation than the upper part (open side). It increases heat dissipation.

  As described above, the case mold type capacitor according to the present invention is excellent in heat dissipation, but the mold resin used has sufficient fluidity, and the mold resin is uniformly filled in the metal case. It is in the state.

Sectional drawing which showed the structure of the capacitor | condenser element of Example 1 The top view which showed a pair of metallized film used for the capacitor | condenser element of Example 1 It is a figure which shows the structure of the case mold type capacitor | condenser of Example 1, (a) is a top view, (b) is sectional drawing. It is a figure which shows the containing state of the filler of the case mold type capacitor of Example 1, (a) is sectional drawing of a case mold type capacitor, (b) is a figure which shows the change of the content rate of a filler. The figure which shows the change of the content rate of the filler of Example 2 The figure which shows the change of the content rate of the filler of Example 3 The figure which shows the change of the content rate of the filler of Example 4 Diagram showing the structure of a conventional case mold type capacitor

Example 1
First, a capacitor element 2 used in the case mold type capacitor 1 of the present embodiment will be described with reference to FIGS.

  Here, FIG. 1 is a cross-sectional view showing the configuration of the capacitor element 2, and FIG. 2 is a plan view showing a pair of metallized films used in the capacitor element 2.

  In FIGS. 1 and 2, for example, the first metallized film 3 is a metallized film for the P electrode, and the second metallized film 4 is a metallized film for the N electrode. Then, the capacitor element 2 which is a film capacitor is formed by superposing these as a pair and winding them a plurality of times.

  As shown in FIG. 1, the first metallized film 3 has a metal vapor-deposited electrode 7a provided with an insulation margin 6a at one end on one surface of a polypropylene film 5a serving as a dielectric. 7a is connected to a metallicon electrode 8a formed on the end face to lead the electrode to the outside. Here, the thickness of this polypropylene film 5a is about 2-4 micrometers, and the capacity | capacitance of the capacitor | condenser element 2 can be made into a desired value by selecting suitably the width | variety and the frequency | count of winding of the polypropylene film 5a.

  The metal vapor-deposited electrode 7a is divided into a plurality of divisions by a non-vapor-deposited slit 9a that does not have a metal vapor-deposited electrode formed by oil transfer on the side from the substantially central part of the width W of the effective electrode part forming the capacitance toward the insulation margin 6a. Each is divided into electrodes 10a. Further, as shown in FIG. 2 (a), these divided electrodes 10a are formed of a polypropylene film 5a located on the side opposite to the insulation margin 6a from the approximate center of the width W of the effective electrode portion and on the side close to the metallicon electrode 8a. The metal vapor deposition electrode 7a vapor-deposited on the whole surface is connected in parallel by a fuse 11a.

  The fuse 11 a has a self-protection function for the capacitor element 2. That is, when an abnormality occurs during the operation of the capacitor element 2, the fuse 11a connected to the divided electrode 10a causing the abnormality evaporates, and the divided electrode 10a is disconnected from the metal vapor-deposited electrode 7a. The function of the capacitor element 2 as a capacitor is maintained by minimizing the capacity reduction without destruction.

  The second metallized film 4 has the same configuration as the first metallized film 3 as shown in FIGS. 1 and 2B. Therefore, description of the configuration of the second metallized film 4 is omitted.

  Similarly to the first metallized film 3, the second metallized film 4 also includes a fuse 11b. When the abnormality occurs, the fuse 11b is disconnected to maintain the function of the capacitor element 2 as a capacitor.

  Here, the metal vapor deposition electrode 7a, the division | segmentation electrode 10a, the metal vapor deposition electrode 7b, and the division | segmentation electrode 10b demonstrated so far are described in detail.

  The metal vapor-deposited electrode 7a, the divided electrode 10a, the metal vapor-deposited electrode 7b, and the divided electrode 10b are formed by vapor-depositing an alloy composed of aluminum and magnesium. In this embodiment, the mixing ratio of aluminum and magnesium is 95. : 5.

  In general, the thermodynamic stability of metal to water is represented by a pool bay diagram, but the lower the thermodynamic stability represented by this pool bay diagram, the easier it is to react with moisture, that is, the ability to remove moisture. Is. Here, since magnesium is a substance having low thermodynamic stability and excellent water removal capability, the first metallized film 3 and the second metallized film 2 are formed in the capacitor element 2 of this embodiment in which an alloy using magnesium is deposited. Water inside the metallized film 4 and the surface can be removed, and the path of leakage current can be reduced. As a result, the characteristic deterioration of the capacitor element 2 can be suppressed.

  According to the pool bay diagram described above, metals such as titanium and manganese have low thermodynamic stability and excellent moisture removal ability in addition to magnesium, but the boiling point is low when considering the evaporation process during capacitor production. Since a high vapor pressure is preferable, magnesium having a higher vapor pressure than titanium and manganese is particularly preferable.

  Next, the configuration of the case mold type capacitor 1 of the present embodiment using the capacitor element 2 described above will be described with reference to FIGS. 3 (a) and 3 (b).

  Here, FIG. 3A is a top view of the case mold type capacitor 1 of this embodiment, and FIG. 3B is a cross-sectional view of the case mold type capacitor 1.

  As shown in FIGS. 3A and 3B, the case mold type capacitor 1 is configured by accommodating a capacitor element 2 in an aluminum case 12 in a state where the capacitor element 2 is adjacent thereto.

  As shown in FIGS. 3A and 3B, the case 12 has a box shape having an opening surface 12a having one end opened to the outside. The opening surface 12a serves as a casting surface for casting a resin 13 described later.

  A bus bar 14 is welded to the metallicon electrode 8 a and the metallicon electrode 8 b of the capacitor element 2, and the capacitor elements 2 housed in the case 12 are electrically connected to each other by the bus bar 14. As shown in FIG. 3B, the bus bar 14 includes a built-in portion 14a built in the case 12 and an exposed portion 14b exposed to the outside of the case 12, and the built-in portion 14a and the exposed portion are exposed. The part 14b is integrated. As described above, the built-in portion 14a is a portion welded to the metallicon electrode 8a and the metallicon electrode 8b of the capacitor element 2, and the exposed portion 14b is a portion connected to an external device or the like (not shown).

  The capacitor element 2 is fixed in the case 12 by placing the capacitor element 2 at a predetermined position in the case 12 and then filling and solidifying the resin 13. In this embodiment, an epoxy resin is used as the resin 13 filled in the case 12. The positioning of the capacitor element 2 in the case 12 is performed by a plurality of supports 15 provided on the inner bottom surface 12b of the case 12, as shown in FIG. That is, before filling the resin 13, for example, the support 15 is fitted and fixed in a hole provided at a predetermined position on the inner bottom surface 12 b of the case 12, and the capacitor element 2 is placed in the case 12 according to the position of the support 15. To place. Then, by injecting the resin 13, the capacitor element 2 is fixed in the case 12 while being positioned at a predetermined position.

  Here, as the support 15, it is desirable to use an insulating material having excellent thermal conductivity. Specifically, an insulating material selected from silica, alumina, magnesium oxide, silicon nitride, boron nitride, and aluminum nitride as an insulator, a resin mixed with zinc oxide or silicon carbide as a semiconductor, and a surface covered with an insulator A material such as copper, aluminum, or iron as a conductor can be used. From the viewpoint of cost, alumina and magnesium oxide are suitable.

  Further, as the support 15, the fiber direction of the insulating fiber material such as carbon fiber, glass fiber, ultrahigh molecular weight polyethylene fiber, liquid crystal resin fiber, etc. is aligned with the direction in which heat conduction is desired, and is coated with a resin so as to bind them. It is also possible to use one having a constitution (heat conduction is extremely high in the fiber direction and low between the fibers).

  The mounting leg 16 is used for mounting the case mold type capacitor 1 to an external device. Although this attachment method is not particularly limited, for example, as shown in FIG. 3 (a), an attachment hole 16a is provided at the distal end portion of the attachment leg 16, and a bolt is passed through the attachment hole 16a. You may attach to. As shown in FIGS. 3A and 3B, when the resin 13 is injected into the case 12, the opening surface 12a of the case 12 is set to the upper side, and the resin is introduced from the upper part of the case 12 to the inside of the case 12. However, when actually attaching to an external device, it is not limited to this mode. That is, when attaching to an external device, the opening surface 12a of the case 12 may be the lower side. As long as the resin 13 is sufficiently solidified, the solidified resin 13 does not peel from the inside of the case 12 even if it is attached to an external device with the opening surface 12a of the case 12 on the lower side.

  Next, the resin 13 which is the point of the present invention will be described with reference to FIGS. 4 (a) and 4 (b). Here, FIG. 4A is a cross-sectional view of the case mold type capacitor 1, and FIG. 4B is a diagram showing a change in the filler content of the resin 13. In FIG. 4 (a), the state of the resin 13 is shown in a simplified manner than the cross-sectional view of the case mold type capacitor 1 shown in FIG. 3 (b) (that is, the bus bar 14 and the support body). 15 etc. are not shown). 4B, the position of the inner bottom surface 12b of the case 12 is a base point (that is, 0), and the opening surface 12a is the end point (that is, 1). The change of content rate (vol%) is shown. The content was determined by cutting out a resin at a predetermined position and observing the cross section with an SEM, or heating at 600 to 800 ° C. and measuring the ash content.

  In this embodiment, an epoxy resin is used as the resin 13 as described above. Since the epoxy resin is relatively excellent in water resistance and moisture resistance, the use of the epoxy resin as the resin 13 makes the capacitor element 2 of this embodiment less susceptible to external moisture and suppresses deterioration of its characteristics. It has become.

  In addition, the resin 13 of this example contains a filler. As the filler, those having high thermal conductivity and insulating properties are desirable. For example, silica, boron nitride, alumina, titanium oxide, white carbon, mica, glass fiber, or a mixture thereof is desirably used. Among them, it is desirable to use boron nitride having excellent thermal conductivity and silica from the viewpoint of reliability and cost.

  Here, the characteristics peculiar to the present embodiment of the resin 13 will be described.

  In the resin 13 of this example, the content of the filler contained in the resin 13 is continuously changed from the inner bottom surface 12b of the case 12 to the opening surface 12a. That is, in the case mold type capacitor 1 of this embodiment, as shown in FIG. 4A, the resin 13 is uniformly filled in the hollow portion of the case 12 from the inner bottom surface 12b to the upper end portion (opening surface 12a) of the side wall. However, the content of the filler contained in the resin 13 varies so as to gradually decrease from the inner bottom surface 12b of the case 12 to the opening surface 12a, as shown in FIG. 4B. In particular, in this embodiment, in the region from the inner bottom surface 12b of the case 12 to the lower end portion of the capacitor element 2, the content of the filler contained in this region is adjusted to be 40 vol% or more. In addition, this area | region is an area | region enclosed with the broken line in Fig.4 (a), and is shown as the area | region A in FIG.4 (a) and FIG.4 (b).

  On the other hand, since the filler content in the resin 13 is continuously reduced as described above, the filler content in the region from the lower end portion to the upper end portion of the capacitor element 2 is the inner bottom surface of the case 12. It becomes lower than the filler content from 12b to the lower end of the capacitor element 2.

  Further, the content of the filler contained in the resin 13 is the smallest in the region from the upper end portion of the capacitor element 2 to the opening surface 12a, and in the vicinity of the opening surface 12a of the case 12 (the right end portion of the curve in FIG. 4B). The lowest configuration. The filler content in the vicinity of the opening 12a may be appropriately adjusted depending on the environment to which the case mold type capacitor 1 is exposed. For example, in actual use, if the opening surface 12a is sealed by some means such as a lid, and the thermal shock is not easily applied to the inside of the case mold type capacitor 1, the filler content is as low as 20 vol% or less. It doesn't matter.

  Hereinafter, effects of the configuration of the case mold type capacitor 1 of the present embodiment will be described.

  First, the case mold type capacitor 1 of this embodiment has excellent heat dissipation. This is because the content of the filler contained in the resin 13 is gradually reduced from the inner bottom surface 12b of the case 12 to the opening surface 12a.

  That is, the case 12 of this embodiment is made of aluminum, which is a metal, and has excellent heat dissipation. However, as shown in FIG. The inner bottom surface 12b side capable of radiating heat to the outside through the aluminum plate constituting the case 12 is more excellent in heat dissipation than the 12a side. Therefore, in the case mold type capacitor 1 of the present embodiment, a large amount of filler is contained in the resin 13 on the inner bottom surface 12b side, which is excellent in heat dissipation, so that heat generated from the capacitor element 2 can be transferred to the inner bottom surface of the case 12 via the filler. 12b is conducted to actively dissipate heat to the outside.

  As a result, in this embodiment, by making the distribution state of the filler in the resin 13 characteristic, it is possible to efficiently dissipate heat compared to the case where the same amount of filler is uniformly dispersed in the resin 13. Is possible.

  As described above, in the case mold type capacitor 1 of the present embodiment, the heat of the case mold type capacitor 1 during driving is effectively radiated to the outside, and the heat resistance is improved, thereby reducing the deterioration of the capacitor characteristics. It has become a high thing.

  In particular, in the present embodiment, in the region A from the inner bottom surface 12b of the case 12 to the lower end portion of the capacitor element 2, the content of the filler contained in this region is adjusted to be 40 vol% or more. The results of verifying the content of the case mold type capacitor 1 and the filler in the region A are shown in Table 1.

  As shown in (Table 1), in order to make the content of the filler in the region A 30 vol%, 40 vol%, and 50 vol% in this example, the viscosity is 1000 mPa / s, 1700 mPa / s, 2000 mPa / s at 60 ° C. Resin 13 which is s was used. On the other hand, when the filler content of the entire resin 13 is constant as in a conventional case mold type capacitor, the viscosity is set to 60 ° C. in order to set the content of the region A to 30 vol%, 40 vol%, and 50 vol%. Therefore, the resin 13 of 1600 mPa / s, 4000 mPa / s, and 7500 mPa / s had to be used. From this, it can be seen that in the configuration of the conventional case mold type capacitor, since the viscosity of the resin 13 is high, it is difficult to sufficiently fill the inside of the case 12 with the resin 13.

  When a current was passed through the capacitor element 2 (25 μF) under each condition at 10 Arms and 10 KHz, the capacitor element 2 showed a temperature rise as indicated by ΔT in (Table 1).

  The cross-section of the solidified resin 13 was observed with a scanning electron microscope (SEM). As a result, the case mold type capacitor 1 of Example 1 showed no voids under any conditions. In the capacitor, voids were generated under the conditions of 40 vol% and 50 vol%. When voids are generated in this way, partial discharge occurs and causes insulation failure. Alternatively, moisture may enter the void from the outside, and the quality of the case mold capacitor 1 as a finished product may be deteriorated.

  That is, when the content of the filler in the region A is 40 vol% or more, voids are generated in the conventional case mold type capacitor, whereas in the configuration of this example, heat dissipation is ensured without generation of voids. It can be seen that it also has excellent reliability.

  Further, in the case mold type capacitor 1 of the present embodiment, as shown in FIG. 3B, a support 15 having excellent thermal conductivity is provided, and the heat generated from the capacitor element 2 is the support 15. Heat is conducted to the outside. Thus, the heat resistance of the case mold type capacitor 1 of the present embodiment is further improved by providing the support 15 having excellent thermal conductivity.

  In addition to enhancing the heat resistance of the case mold type capacitor 1, the filler is also expected to have an effect of preventing the ingress of moisture from the outside. However, in the case mold type capacitor 1 of the present embodiment, the resin 13 on the opening surface 12 a side is not affected. Since the filler content is relatively low, moisture may enter the case mold type capacitor 1 from the opening surface 12a side. Therefore, the metal vapor-deposited electrode 7a, the divided electrode 10a, the metal vapor-deposited electrode 7b, and the divided electrode 10b of the capacitor element 2 of this embodiment are formed using an alloy composed of aluminum and magnesium having an excellent water removal capability. . For this reason, even if moisture enters the case mold type capacitor 1, this moisture is removed and the path of leakage current can be reduced. Therefore, the case mold type capacitor 1 of the present embodiment is excellent in heat resistance as described above, and at the same time has sufficient characteristics in terms of moisture resistance, and has high reliability. Note that the moisture resistance of the case mold type capacitor 1 is further enhanced by using an epoxy resin having excellent moisture resistance as the resin 13.

  Moreover, in order to give the above-described characteristics to the distribution of the filler in the resin 13, it is desirable to use a filler having a large particle size. The filler having a large particle size is relatively easily settled, and the filler 13 content of the resin 13 can be gradually reduced from the inner bottom surface 12b side to the opening surface 12a side. A filler having a particle size of 30 μm or more is preferable. By using a filler of this size, the filler can be dispersed as described above.

  Specifically, silica having a particle size of 30 μm or more is dispersed in an epoxy resin, and this epoxy resin is injected into the hollow portion of the case 12 and heated and solidified to obtain a filler dispersed state as described above. . As a heating method, a constant temperature bath is used and heat is gradually applied. This is because when heated over time, the silica settles on the inner bottom surface 12b of the case 12, and the filler distribution as shown in FIG. That is, the filler distribution in the resin 13 can be adjusted only by appropriately changing the dispersion treatment conditions and the heating time. For example, when it is desired to increase the filler content in the vicinity of the inner bottom surface 12b, the heating time may be increased.

  In addition, it can be set as the dispersion state of the above fillers also by using a filler with large specific gravity. For example, since alumina has a relatively large specific gravity and easily settles, the dispersion state as described above can be formed by using this as a filler.

  Moreover, in order to make the content rate of the filler high on the inner bottom surface 12b side and low on the opening surface 12a side, for example, the resin 13 is divided into a plurality of layers as a configuration other than the embodiment, and the filler contained in each layer Although it is possible to change the amount, in this case, it is necessary to prepare a plurality of resins 13 having different filler contents when the case mold type capacitor 1 is manufactured. On the other hand, as described above, the case mold type capacitor 1 of the present embodiment may be configured such that the filler content is high on the inner bottom surface 12b side and the opening surface 12a side is low only by appropriately changing the heating method at the time of production. It can be manufactured easily, and the productivity is excellent.

  In general, when a large amount of filler is contained in an epoxy resin or the like, the fluidity of the resin 13 deteriorates, and there is a possibility that the resin cannot be sufficiently filled up to every corner of the hollow portion of the case 12. The resin 13 in the example has a characteristic in the distribution of the filler, and the filler content itself is equivalent to the conventional one, so that the fluidity is not impaired, and the resin 13 is uniformly distributed to every corner of the hollow portion of the case 12. Can be filled. Further, when the resin 13 is injected into the case 12, if the distribution of the filler contained in the resin 13 before filling is biased, it is considered that the fluidity at the time of filling is affected. However, since the filler distribution in this embodiment is formed by filling the hollow portion of the case 12 with the resin 13 and then allowing the filler to settle, the resin 13 before being injected into the case 12 is uniformly filled with filler. Distributed. Therefore, the resin 13 at the time of pouring has sufficient fluidity, and from this, the resin 13 can be filled into the case 12 without any problem.

  As described above, the case mold type capacitor 1 of the present example is excellent in heat resistance, has high moisture resistance, is highly reliable, and is excellent in productivity.

(Example 2)
Hereinafter, the configuration of the case mold type capacitor 21 in this embodiment will be described.

  In the case mold type capacitor 21 in the present embodiment, the distribution state of the filler in the resin 22 is different from that in the first embodiment, and the configuration other than this is the same as that in the first embodiment. The same reference numerals are used, and only different parts will be described with reference to the drawings.

  The distribution of the filler of the resin 22 of this example will be described with reference to FIG.

  Here, FIG. 5 is a diagram showing a change in the content of the filler of the resin 22. FIG. 5 shows the change in the filler content from the inner bottom surface 12b to the opening surface 12a when the position of the inner bottom surface 12b of the case 12 is the base point and the opening surface 12a is the end point, as in the first embodiment. Yes.

  As shown in FIG. 5, the resin 22 filled in the case 12 of the present embodiment has a first region where the filler content is substantially constant, and the filler content is toward the opening surface 12 a of the case 12. It is divided into a second region that gradually decreases.

  The first region exists from the inner bottom surface 12 b to the vicinity of the lower end portion of the capacitor element 2. In this first region, the filler content is substantially constant, and in the resin 22, this first region is the region containing the most filler.

  A second region exists from the upper end of the first region to the opening 12a. In the second region, the filler content is continuous with the filler content in the first region, and gradually decreases from the upper end of the first region toward the opening 12a of the case 12. As shown in FIG. 5, the second region exists in a part of the region A and from the lower end portion of the capacitor element 2 to the opening surface 12 a. However, the second region may not include the region A. That is, in this case, the region A is included in the first region, and the filler content in the region A is substantially constant.

  The filler content in region A is preferably 40 vol% or more for the same reason as in Example 1.

  The effect by the structure of a present Example is described below.

  In the case mold type capacitor 21 in the present embodiment, the heat dissipation can be further improved. This is because a sufficient amount of filler is contained in the vicinity of the inner bottom surface 12b to form the first region in which the filler content is substantially constant.

  Table 2 shows the results of verifying the heat dissipation of the case mold type capacitor 21 of this example.

  In the verification in (Table 2), the filler content in the region A was set to 50 vol% as the maximum value (that is, the filler content in the vicinity of the inner bottom surface 12b was 50 vol%, and gradually decreased toward the opening surface 12a). The case mold type capacitor 1 of Example 1 and the filler are uniformly dispersed in the region A, and the filler content in the region A is a constant value of 50 vol% (that is, the region A is included in the fifth region). The heat dissipation of the case mold type capacitor 21 was compared. In this verification, a temperature rise value was measured when a current of 10 Arms and 10 KHz was passed through the capacitor element 2 having a capacitance of 25 μF.

  As shown in Table 2, the case mold type capacitor 1 of Example 1 showed a temperature rise of 7.5 ° C., whereas the case mold type capacitor 21 of Example 1 had a temperature increase of 6.8 ° C. An increase in temperature was observed. As is clear from this, the heat dissipation can be further improved according to the embodiment.

  Further, in order to obtain the filler distribution as shown in FIG. 5, after injecting the resin 22 into the case 12, it may be heated more time than Example 1. By taking time for heating, more fillers are settled, and the settled fillers are accumulated in the vicinity of the inner bottom surface 12b, whereby a filler distribution state as shown in FIG. 5 can be obtained.

  As the filler to be used, silica having a particle diameter of 30 μm or more, or a filler such as alumina having a relatively large specific gravity is preferable as in Example 1.

(Example 3)
Hereinafter, the configuration of the case mold type capacitor 31 in the present embodiment will be described.

  In the case mold type capacitor 31 in this embodiment, the distribution state of the filler in the resin 32 is different from that in the first embodiment and the second embodiment, and the other configurations are the same. The same reference numerals are used, and only different parts will be described with reference to the drawings.

  The distribution of the filler of the resin 32 of the present embodiment will be described with reference to FIG.

  Here, FIG. 6 is a diagram showing a change in the filler content of the resin 32. In addition, like Example 1 and Example 2, in FIG. 6, the content of the filler from the inner bottom surface 12b to the opening surface 12a when the position of the inner bottom surface 12b of the case 12 is a base point and the opening surface 12a is an end point is shown. It shows a change.

  As shown in FIG. 6, the resin 32 filled in the case 12 of this embodiment has a third region where the filler content gradually decreases toward the opening surface 12 a of the case 12, and the filler content is substantially constant. Into a fourth region. As shown in FIG. 6, the third region and the fourth region are located on the inner bottom surface 12b side of the case 12, and the fourth region is located on the opening surface 12a side.

  Here, the resin 32 of the present embodiment contains a filler having a small particle size in addition to silica having a particle size of 30 μm or more. More specifically, this example further contains silica having a particle size of 5 μm or less. A filler with a small particle size has a characteristic that it is harder to settle than a filler with a large particle size, and by adding dispersion treatment conditions and surface treatment to this, a filler distribution as shown in FIG. 6 is formed. Yes.

  That is, in this example, as in Example 1 and Example 2, the content of the filler near the inner bottom surface 12b is increased by heating over time when the resin 32 is solidified. Since the small particle size filler used in this example hardly settles down, it remains in the vicinity of the opening surface 12a even after the heating, and is in a state of being dispersed substantially uniformly in the resin 32. On the other hand, silica having a large particle diameter of 30 μm or more is dispersed in the resin 32 so that the content thereof gradually decreases from the inner bottom surface 12b toward the opening surface 12a as in the first embodiment.

  As a result, the filler is distributed as shown in FIG.

  Therefore, in the resin 32 of this example, there are many fillers having a large particle size near the inner bottom surface 12b, and many fillers having a small particle size are present near the opening surface 12a.

  For the same reason as in Example 1 and Example 2, the filler content in region A is desirably 40 vol% or more.

  The effect by the structure of a present Example is described below.

  The case mold type capacitor 31 of the present example has excellent heat dissipation as well as excellent thermal shock resistance as the case mold type capacitor 1 of Example 1.

  Table 3 shows the results of a temperature cycle test verified with respect to the thermal shock resistance of the case mold type capacitor 31 of this example.

  In this verification, the resin 32 is not broken at each filler content (10 vol%, 20 vol%, 30 vol%, 40 vol%) in the fourth region when the filler content in the vicinity of the inner bottom surface 12 b is 50 vol%. The temperature range is obtained. The size of the case 12 used is 10 cm × 10 cm × 10 cm, and the number of cycles is 1000 cycles. For example, when each content rate of the filler in the 4th field is 10 vol%, even if it changed temperature 1000 times in the temperature range of 90 ° C, a crack etc. did not arise.

  From this result, it is clear that the case mold type capacitor 31 of this example is excellent in thermal shock resistance, and further excellent thermal shock resistance can be obtained by increasing the filler content in the fourth region. I understood it.

  As described above, in this example, by using two types of fillers having different particle sizes, the distribution state of the fillers in the resin 32 can be adjusted as appropriate, and the case has excellent heat dissipation, moisture resistance, and thermal shock resistance. A molded capacitor 31 can be provided.

  In addition, as a filler to be settled near the inner bottom surface 12b, a filler having a large specific gravity such as alumina may be used as in the first and second embodiments.

Example 4
Hereinafter, the configuration of the case mold type capacitor 41 in the present embodiment will be described.

  In the case mold type capacitor 41 in the present embodiment, the distribution state of the filler in the resin 42 is different from that in the first embodiment, the second embodiment, and the third embodiment. The description will be omitted with the same reference numerals, and only different parts will be described with reference to the drawings.

  The distribution of the filler of the resin 42 of the present embodiment will be described with reference to FIG.

  Here, FIG. 7 is a diagram showing a change in the filler content of the resin 42. As in the first, second, and third embodiments, in FIG. 7, the filler from the inner bottom surface 12b to the opening surface 12a when the position of the inner bottom surface 12b of the case 12 is the base point and the opening surface 12a is the end point. The change of the content rate of is shown.

  As shown in FIG. 7, the resin 42 filled in the case 12 of this embodiment is divided into a fifth region, a sixth region, and a seventh region, and these regions are the inner bottom surface 12 b of the case 12. To the fifth region, the sixth region, and the seventh region.

  In Example 2 described above, the heat dissipation of the case mold type capacitor 21 is further improved by providing the first region in which the filler content is substantially constant and the filler content is the highest in the vicinity of the inner surface 12b. However, in the case mold type capacitor 41 of the present embodiment, in addition to the embodiment 2, the filler content in the vicinity of the opening surface 12a is substantially constant.

  That is, in the fifth region, the filler content is substantially constant and highest, and in the sixth region, the filler content gradually decreases toward the opening surface 12a of the case. The fifth area and the sixth area correspond to the first area and the second area of the second embodiment, respectively. Furthermore, in the present embodiment, a seventh region is further provided from above the sixth region to the opening surface 12a. In the seventh region, the filler content is substantially constant.

  In order to make the filler content as shown in FIG. 7, as the filler contained in the resin 42, the resin 32 in which two kinds of fillers having different particle diameters are mixed as in Example 3 is used. It is formed. Alternatively, alumina having a relatively large specific gravity or the like may be used as a filler that settles in the vicinity of the inner bottom surface 12b. Here, in the case mold type capacitor 31 of the third embodiment, the filler distribution as shown in FIG. 6 is obtained by using two kinds of fillers similar to the present embodiment. Then, the heating method at the time of solidifying the resin is different, and due to the difference in the heating method, the distribution of the filler as shown in FIG. That is, in this example, heating is performed over a period of time as compared with Example 3. In this way, by taking time for heating, more filler settles and accumulates in the vicinity of the inner bottom surface 12b, so that the distribution state of the filler in the vicinity of the inner bottom surface 12b becomes as shown in FIG. Since the filler having a small particle size has a property of being difficult to settle, even if heating is performed for a long time, many spherical fillers remain in the vicinity of the opening 12a of the case 12 after the heating. As a result, a filler distribution state as shown in FIG. 7 is obtained.

  For the same reason as in Examples 1 to 3, the filler content in region A is preferably 40 vol% or more.

  The effect by the structure of a present Example is described below.

  In the case mold type capacitor 41 in the present embodiment, the heat dissipation can be further improved. This is because a fifth region is formed in which a sufficient amount of filler is contained in the vicinity of the inner bottom surface 12b and the filler content is substantially constant.

  Here, the results of verifying the heat dissipation of the case mold type capacitor 41 of this example and the case mold type capacitor 31 of Example 3 are shown in Table 4.

  In the verification shown in (Table 4), the filler content in the region A is the maximum value of 50 vol% (that is, the filler content in the vicinity of the inner bottom surface 12b is 50 vol%, and gradually decreases toward the opening surface 12a). The case mold type capacitor 31 of Example 3 and the filler uniformly distributed in the region A, and the filler content in the region A is a constant value of 50 vol% (that is, the region A is included in the fifth region). The heat dissipation of the case mold type capacitor 41 was compared. In this verification, a temperature rise value was measured when a current of 10 Arms and 10 KHz was passed through the capacitor element 2 having a capacitance of 25 μF.

  As a result of the verification, a temperature rise of 7.1 ° C. was measured for the case mold type capacitor 31 of Example 3, whereas a temperature rise of 6.6 ° C. was measured for the case mold type capacitor 41 of this example. It was. Also from this result, according to the configuration of the present embodiment, it can be seen that the heat dissipation of the case mold type capacitor 41 can be further improved.

  And since the case mold type capacitor 41 of the present embodiment has a seventh region, it has excellent thermal shock resistance like the case mold type capacitor 31 of the third embodiment.

  Thus, the case mold type capacitor of this example has excellent heat dissipation and thermal shock resistance, and has high reliability.

  In the first to fourth embodiments, the opening surface 12a of the case 12 has been described as the upper side. However, as described in the first embodiment, the mode in which the opening surface 12a is necessarily the upper side when actually attached to an external device. It is not limited to. That is, you may attach the opening surface 12a as a lower side.

  Moreover, in the said Example 1- Example 4, although demonstrated using the example which used the polypropylene film as a dielectric material film, this invention is not limited to this. For example, in addition to a polypropylene film, a film such as polyethylene terephthalate or polyphenylene sulfide can exhibit the effects of the present invention.

  The case mold type capacitor according to the present invention is excellent in heat dissipation, moisture resistance and thermal shock resistance and has high reliability. Therefore, the case mold type capacitor of the present invention can be suitably used as various capacitors used in various electronic devices, electrical devices, industrial devices, automobiles, etc., and is particularly useful in the automotive field where high heat resistance and high moisture resistance are required. is there.

DESCRIPTION OF SYMBOLS 1 Case mold type capacitor 2 Capacitor element 3 1st metallized film 4 2nd metallized film 5a, 5b Polypropylene film 6a, 6b Insulation margin 7a, 7b Metal vapor deposition electrode 8a, 8b Metallicon electrode 9a, 9b Slit 10a, 10b Divided electrodes 11a, 11b Fuse 12 Case 12a Open surface 12b Inner bottom surface 13 Resin 14 Bus bar 14a Built-in portion 14b Exposed portion 15 Support body 16 Mounting leg 16a Mounting hole 21 Case mold type capacitor 22 Resin 31 Case mold type capacitor 32 Resin 41 Case Molded capacitor 42 Resin

Claims (8)

A capacitor element formed by winding or laminating a pair of metallized films on which a metal-deposited electrode is formed on a dielectric film;
A top-opening metal case containing the capacitor element;
A case mold type capacitor comprising a resin filled in the metal case;
The resin contains a filler,
A case mold type capacitor in which the content of the filler with respect to the resin gradually decreases from the inner bottom surface of the metal case toward the opening surface of the metal case. A capacitor element formed by winding or laminating a pair of metallized films on which a metal-deposited electrode is formed on a dielectric film;
A top-opening metal case containing the capacitor element;
A case mold type capacitor comprising a resin filled in the metal case;
The resin contains a filler and a first region in which the filler content relative to the resin is substantially constant; and a second content in which the filler content relative to the resin gradually decreases toward the opening of the metal case. A case mold type capacitor in which the second region is located closer to the opening surface than the first region. A capacitor element formed by winding or laminating a pair of metallized films on which a metal-deposited electrode is formed on a dielectric film;
A top-opening metal case containing the capacitor element;
A case mold type capacitor comprising a resin filled in the metal case;
The filler content rate relative to the resin is divided into a third region where the filler content rate gradually decreases toward the opening surface of the metal case, and a fourth region where the filler content rate relative to the resin is substantially constant. The case mold type capacitor is located on the opening surface side of the third region. A capacitor element formed by winding or laminating a pair of metallized films on which a metal-deposited electrode is formed on a dielectric film;
A top-opening metal case containing the capacitor element;
A case mold type capacitor comprising a resin filled in the metal case;
A fifth region in which the filler content relative to the resin is substantially constant; a sixth region in which the filler content relative to the resin gradually decreases toward the opening of the metal case; and the filler relative to the resin. The fifth region, the sixth region, and the seventh region are divided into a seventh region in which the content rate of the metal case is substantially constant, and the fifth region, the sixth region, and the seventh region are the fifth region from the inner bottom surface of the metal case toward the opening surface. A case mold type capacitor located in the order of the sixth region and the seventh region. The case mold type capacitor according to any one of claims 1 to 4, wherein an alloy composed of aluminum and magnesium is used for at least one of the metal deposition electrodes of the pair of metallized films. The case mold type capacitor according to claim 1, wherein the filler is made of at least one of silica, alumina, and boron nitride. The case mold type capacitor according to claim 1, wherein an epoxy resin is used as the resin. The case metal mold capacitor according to claim 1, wherein the metal case is made of aluminum.

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