capacitor

Abstract

To provide a capacitor which can radiate internal heat efficiently and inhibit increase in the size.SOLUTION: A bus bar 6 is connected to capacitor elements 5 and housed in a case 2 and the case 2 is filled with a resin 4 to form a capacitor. Heat radiation members 3 are insert-molded into the case 2 so as to be flush with a case outer surface 2d. Each heat radiation member 3 has a protruding part 3b protruding to the inner side of the case 2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a capacitor provided with a heat dissipation member. [Background technology]

[0002] Conventionally, a heat dissipation member has been installed to dissipate heat from a capacitor. For example, Patent Document 1 describes attaching a heat dissipation member to the side of a case with an adhesive. Patent Document 2 describes insert-molding a heat dissipation member into a case. Patent Document 3 describes housing a heat dissipation member inside a case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-187206 [Patent Document 2] Japanese Patent Application Laid-Open No. 2012-199350 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-191805 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Documents 1 and 2, the heat dissipation member is provided only on the surface of the case, making it difficult to dissipate heat to the inside of the capacitor. In Patent Document 3, the heat dissipation member protrudes significantly outside the case, making the capacitor larger.

[0005] An object of the present invention is to provide a capacitor that can efficiently dissipate internal heat and can prevent an increase in size. [Means for solving the problem]

[0006] The capacitor of the present invention is a capacitor in which a capacitor element 5 connected to a bus bar 6 is housed in a resin case 2 and filled with resin 4, and is characterized in that a heat dissipation member 3 is insert-molded into the case 2 so as to be flush with the outer surface 2d of the case, and the heat dissipation member 3 has a protrusion 3b that protrudes toward the inside of the case 2.

[0007] Moreover, it is preferable that the heat dissipation member 3 straddles a plurality of wall surfaces (2a, 2b) of the case 2.

[0008] Furthermore, it is preferable that the protrusions 3b of the heat dissipation member 3 are positioned between the capacitor elements 5 or between the capacitor elements 5 and the wall surfaces (2a, 2b) of the case 2. [Effects of the Invention]

[0009] In the capacitor of the present invention, the heat dissipation member is insert-molded so as to be flush with the outer surface of the case, which prevents the capacitor from becoming large. Furthermore, the heat dissipation member has a protrusion that protrudes toward the inside of the case, which allows for efficient dissipation of internal heat.

[0010] When the heat dissipation member spans multiple wall surfaces of the case, heat inside the case can be efficiently dissipated from multiple directions.

[0011] When the protruding portions of the heat dissipation member are positioned between the capacitor elements or between the capacitor elements and the wall surface of the case, the heat of the capacitor elements can be dissipated efficiently. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is an exploded perspective view showing a capacitor according to an embodiment of the present invention. [Figure 2] FIG. 2A is a horizontal cross-sectional view of the capacitor, and FIG. 2B is a vertical cross-sectional view. [Figure 3] 3A to 3C are horizontal cross-sectional views showing modified examples of the heat dissipation member. [Figure 4] 1 is a vertical cross-sectional view showing a capacitor according to a different embodiment of the present invention. [Figure 5] FIG. 10 is a vertical cross-sectional view showing a capacitor according to yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Next, one embodiment of a capacitor of the present invention will be described in detail with reference to the drawings. As shown in Figures 1 and 2, this capacitor 1 includes a case 2, a heat dissipation member 3 insert-molded into the case 2, a capacitor element 5 housed in the case 2, a bus bar 6 connected to the capacitor element 5, and a resin 4 filled into the case 2. Each of the above components will be described below, but the concepts of "upper and lower" refer to those during manufacturing, more specifically, during resin filling, and do not necessarily define upper and lower during use.

[0014] The case 2 is made of resin (e.g., synthetic resin) and is insulating. The case 2 is a roughly hollow rectangular parallelepiped and is composed of multiple walls. The bottom wall 2a that forms the bottom of the case 2 and the side wall 2b that forms the side of the case 2 are both roughly rectangular. An opening 2c is provided at the top end of the case 2. The capacitor element 5 and resin 4 are housed inside through this opening 2c. The heat dissipation member 3 is insert-molded into this case 2 so that it is flush with (on the same plane as) the case outer surface 2d. Note that "flush" also includes cases where, despite being flush during the design process, unintended misalignment (manufacturing error) occurs between the case outer surface 2d and the heat dissipation member 3 due to shrinkage deformation (sink marks, warpage, etc.) during or after manufacturing.

[0015] The case 2 having the above configuration is manufactured, for example, by setting the heat dissipation member 3 in an insert molding machine (mold) for molding cases and then injection molding a resin (e.g., synthetic resin). Specifically, the resin is injection molded with the surface of the heat dissipation member 3 (specifically, the surface of the base 3a, described below) abutting against the inner surface of the mold that will form the case outer surface 2d (the outer surfaces of the bottom wall surface 2a and side wall surfaces 2b). The finished case 2 has a flat seam between the case outer surface 2d and the heat dissipation member 3, so when a wide cooling body is brought into contact with the heat dissipation member 3, the cooling body will also abut against the case 2.

[0016] The heat dissipation member 3 has a base 3a insert-molded into the wall surface of the case 2 and a protrusion 3b protruding from the base 3a toward the inside of the case 2. The base 3a is insert-molded into the side wall surface 2b. The base 3a and the side wall surface 2b have the same thickness. Therefore, the base 3a directly contacts the filled resin 4. In this state, the base 3a can be said to constitute part of the wall surface of the case 2. The exposed surface of the base 3a, i.e., the portion facing the outside air, is flat (smooth). This exposed surface is used as a contact portion for contacting a cooling body. The surface opposite the exposed surface is also flat, but may have irregularities. The protrusion 3b protrudes perpendicular to the base 3a in a plan view and is located between the capacitor elements 5. The tip of the protrusion 3b is embedded in the side wall surface 2b opposite the base 3a, but it does not have to be embedded. The heat dissipation member 3 is formed from a plate or sheet of a highly heat-dissipating material, such as a metal plate made of aluminum or copper, or a material made of ceramics or carbon fiber. Therefore, both the base 3a and the protruding portions 3b are plate-shaped or sheet-shaped. The base 3a and the protruding portions 3b may be formed by bending a single sheet of material, or may be connected by welding or bonding multiple materials.

[0017] The resin 4 filled into the case 2 is an insulating resin. A thermosetting resin or a photocurable resin is preferable, such as an epoxy resin, a urethane resin, or a silicone resin. After the capacitor element 5 connected to the bus bar 6 is housed in the case 2, the resin 4 is filled until the liquid level 4a is above the heat dissipation member 3. However, it is not necessary to fill it all the way up. The resin is also filled to an amount (thickness) that ensures the desired moisture resistance.

[0018] Capacitor element 5 is, for example, a film capacitor in which a metallized film made by vapor-depositing metal onto an insulating film is wound, and has electrode surfaces 5a at both axial ends as shown in Fig. 1. Capacitor element 5 is housed in case 2 with electrode surfaces 5a facing side wall surface 2b of case 2.

[0019] The busbar 6 is composed of one positive busbar 61 and one negative busbar 62. However, it may be composed of a plurality of positive busbars 61 and a plurality of negative busbars 62. The busbar 6 is composed by appropriately bending a conductive metal plate such as copper.

[0020] The positive electrode bus bar 61 includes a vertical portion 61a extending along the side wall surface 2b of the case 2, a horizontal portion 61b extending horizontally from the upper end of the vertical portion 61a and positioned on the opening 2c side, an external connection portion 61c extending upward from the horizontal portion 61b and protruding out of the case through the opening 2c and used for connection to an external device (not shown), and a connection piece 61d extending downward from the lower end of the vertical portion 61a and connected to the electrode surface 5a of the capacitor element 5.

[0021] The negative bus bar 62 includes a vertical portion 62a extending along the side wall surface 2b, an external connection portion 62c extending upward from the upper end of the vertical portion 62a and protruding outward from the case through the opening 2c and used for connecting to an external device (not shown), and a connection piece 62d extending downward from the lower end of the vertical portion 62a and connected to the electrode surface 5a of the capacitor element 5.

[0022] In the capacitor 1 configured as described above, the heat dissipation member 3 is insert-molded into the case 2, so there is no need to assemble the heat dissipation member 3 separately when assembling the capacitor 1. For example, there is no need to position the heat dissipation member 3, which reduces the number of steps. Also, because the case outer surface 2d and the heat dissipation member 3 are flush, the capacitor 1 can be made more compact than one in which the heat dissipation member 3 protrudes from the case outer surface 2d. Furthermore, if the heat dissipation member 3 and the filled resin 4 were in direct contact, there is a possibility that peeling would occur due to differences in expansion coefficients, but because the heat dissipation member 3 is located below the resin liquid surface 4a, peeling can be suppressed.

[0023] The heat dissipation member 3 may be modified as follows. For example, FIG. 3A shows a capacitor 1A in which the protrusion 3b is positioned between the capacitor element 5 and the wall surface (specifically, the side wall surface 2b) of the case 2. It may also be positioned between the capacitor element 5 and the bottom wall surface 2a. FIG. 3B shows a capacitor 1B in which the electrode surface 5a of the capacitor element 5 is oriented vertically and the protrusion 3b is curved along the curved surface on the side surface of the capacitor element 5. FIG. 3C shows a capacitor 1C in which the heat dissipation member 3 and the case 2 have a double structure at the base 3a, and the protrusion 3b penetrates the case 2. For example, if the wall surface of the case 2 is thicker than the base 3a, a double structure is automatically achieved. By not having the protrusion 3b directly contact the filled resin 4, separation due to differences in expansion coefficients does not occur even if the liquid surface 4a of the filled resin 4 is located below the base 3a. Furthermore, the strength of the case can be improved.

[0024] FIG. 4 illustrates another embodiment of the present invention. As shown in the figure, this capacitor 1D has a base 3a including a bottom 3c and side 3d extending upward from both ends of the bottom 3c. The cross-sectional shape is generally U-shaped with the curved portions at right angles. The bottom 3c is insert-molded flush with the bottom wall 2a of the case 2, and the side 3d is insert-molded flush with the side wall 2b of the case 2. This state can be described as a state in which the heat dissipation member 3 spans multiple wall surfaces of the case 2, and is insert-molded so that all surfaces of the case 2 that the heat dissipation member 3 spans are flush with the case outer surface 2d. Therefore, even if a cooling body is in contact with only the bottom wall 2a or one side wall 2b, the entire condenser 1D can be efficiently cooled from multiple sides. Furthermore, the cooling body can be in contact with multiple sides. Examples of cooling bodies include cooling devices equipped with pipes through which water or refrigerant flows, heat sinks, cooling fans, etc., but they also include relatively low-temperature devices.

[0025] Figure 5 shows yet another embodiment of the present invention. As shown in the figure, this capacitor 1E has a heat insulating member 7 insert-molded into it. By providing the heat insulating member 7 in this manner, even if the capacitor 1E is placed close to a heat generating body such as an engine or electronic components, the heat insulating member 7 faces the heat generating body to block heat while allowing heat to be dissipated from the heat dissipation member 3, thereby improving the cooling effect of the entire capacitor 1E.

[0026] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be modified and implemented within the scope of the present invention. For example, in the capacitor 1D of FIG. 4, the heat dissipation member 3 spans the bottom wall surface 2a and the side wall surface 2b of the case 2. However, it may span two or more side wall surfaces 2b without the bottom wall surface 2a. Furthermore, the bottom surface 3c and two side surface portions 3d of the heat dissipation member 3 are all flush with the outer surface 2d of the case. However, only one of the side surface portions 3d may be flush with the outer surface 2d of the case. Furthermore, the protrusion 3b may protrude from either the bottom surface 3c or the side surface portion 3d. Furthermore, when multiple heat dissipation members 3 are provided, one heat dissipation member 3 may directly abut the filled resin 4, while another heat dissipation member 3 may form a dual structure with the case 2.

[0027] Furthermore, while the bottom surface 3c, side surface 3d, and base 3a of the heat dissipation member 3 are each substantially rectangular, they may be other shapes, such as rounded or polygonal. The point is that any shape can efficiently dissipate heat. Furthermore, the shape is not limited to a substantially U-shape, and various shapes, such as an I-shape, an L-shape, a C-shape, a cross shape, or a square shape, may be employed. Furthermore, the shape and size (length and shortness) of the protrusion 3b may be changed as appropriate. For example, it may be an L-shape, a U-shape, or a U-shape with a right-angled curve. Furthermore, the size may be changed to match the size of the capacitor element 5.

[0028] In addition, although the case 2 is rectangular, other shapes, such as those with rounded portions, may be adopted, and changes in shape are within the scope of the design. In Figure 1, the bus bar on the front side is the positive bus bar and the bus bar on the rear side is the negative bus bar, but the positive and negative may be reversed.

[0029] Furthermore, while a film capacitor is used as the capacitor element 5, various other capacitor elements, such as electrolytic capacitors and ceramic capacitors, may also be used. Various shapes, such as a cylindrical or rectangular shape, may also be employed. Size and application are not important. Capacitor elements of different shapes, sizes, applications, and types may be housed in the same case 2. The number of capacitor elements may also be changed as appropriate. The orientation of the capacitor element 5 may be such that the electrode surface 5a faces horizontally or vertically. For example, in the capacitor 1 of FIG. 1, the electrode surface 5a of the capacitor element 5 faces the base 3a of the heat dissipation member 3, and the side surface of the capacitor element 5 faces the protrusion 3b. However, the capacitor element 5 may be arranged so that the electrode surface 5a faces the protrusion 3b and the side surface of the capacitor element 5 faces the base 3a. [Explanation of symbols]

[0030] 1, 1A~E capacitors 2 cases 2a Lower wall surface 2b Side wall 2c opening 2d Case outer surface 3 Heat dissipation materials 3a base 3b Protrusion 3c Bottom part 3d side part 4. Resin 4a Resin liquid level 5 Capacitor elements 5a Electrode surface 6 Busbar 61 Positive bus bar 61a Vertical section 61b Horizontal part 61c External connection part 61d Connection piece 62 Negative bus bar 62a Vertical section 62c External connection part 62d Connecting piece 7. Heat insulating materials

Claims

1. A capacitor in which a capacitor element connected to a bus bar is housed in a resin case and filled with resin, The heat dissipation material is insert-molded into the case so that it is flush with the outer surface of the case. A capacitor in which a heat dissipation member has a base that is flush with the outer surface of the case but does not penetrate the wall of the case, and a protrusion that protrudes from the base toward the inside of the case and penetrates the wall of the case.

2. The capacitor according to claim 1 , wherein the heat dissipation member extends across a plurality of wall surfaces of the case.

3. 3. The capacitor according to claim 1, wherein the protrusions of the heat dissipation member are positioned between the capacitor elements or between the capacitor elements and the wall surface of the case.

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