Capacitor and method for manufacturing the same

Abstract

To provide a capacitor which can increase the heat discharge property and reduce the weight at the same time.SOLUTION: A capacitor 1 includes: a capacitor element 2 having a capacitor end surface electrode 25; an external body 3 for storing the capacitor element 2; and a bus bar 4 connected to the end surface electrode 25 and drawn to the outside of the external body 3. A resin coating film 5 is formed in a bus bar 4 and / or the edge surface electrode 25 in the inner side of the external body 3. The coating film 5 faces a hollow 6 formed between the capacitor element 2 and the external body 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure generally relates to a capacitor and a manufacturing method thereof, and more particularly to a capacitor including a capacitor element, an exterior body, and a bus bar, and a manufacturing method thereof. [Background technology]

[0002] Patent Document 1 discloses a metallized film capacitor. This metallized film capacitor has a capacitor element, a bottomed box-shaped case, and an insulating filling resin. The metallized film capacitor is manufactured by housing the capacitor element in the case and further filling the case with the filling resin.

[0003] However, in the metallized film capacitor of Patent Document 1, the weight of the entire capacitor tends to be large due to the filled resin, and since it takes several hours for the filled resin to harden, productivity tends to be low.

[0004] Therefore, an example of a technique for solving the above problem is disclosed in Patent Document 2. That is, the capacitor of Patent Document 2 includes a capacitor element having a first electrode and a second electrode, and an exterior body that covers the entire capacitor element. Here, the exterior body includes a first exterior body that covers the first electrode side of the capacitor element, and a second exterior body that covers the second electrode side of the capacitor element. The first exterior body and the second exterior body are joined together such that the inside of the exterior body is airtight.

[0005] In this way, in the capacitor of Patent Document 2, the inside of the exterior body is not filled with resin, so that it is possible to reduce the weight and also to increase productivity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2015-103777 A [Patent Document 2] JP 2018-032677 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the capacitor of Patent Document 2 has room for improvement in terms of heat dissipation when current is applied. That is, in the capacitor of Patent Document 2, a small gap is formed between the outer peripheral surface of the capacitor element and the inner peripheral surface of the exterior body. The air present in this gap can act as an insulating layer. This insulating layer makes it easy for heat generated in the capacitor element to be trapped in the area, and can inhibit the transfer of heat to the exterior body. Thus, although the capacitor of Patent Document 2 is designed to be lightweight, the capacitor element is prone to becoming hot when current is applied, and heat dissipation can be reduced.

[0008] An object of the present disclosure is to provide a capacitor that can improve heat dissipation while reducing its weight, and a manufacturing method thereof. [Means for solving the problem]

[0009] A capacitor according to one aspect of the present disclosure includes a capacitor element having an end electrode, an exterior housing that houses the capacitor element, and a bus bar connected to the end electrode and extending to the outside of the exterior housing. A resin coating is formed on the bus bar and / or the end electrode located inside the exterior housing. The resin coating faces a cavity formed between the capacitor element and the exterior housing.

[0010] A method for manufacturing a capacitor according to one aspect of the present disclosure is a method for manufacturing a capacitor including a capacitor element having an end electrode, an exterior body that houses the capacitor element, and a bus bar connected to the end electrode and extended to the outside of the exterior body, the method including the steps of forming a resin coating on the bus bar and / or the end electrode that will be present inside the exterior body, and housing the capacitor element in the exterior body such that the resin coating faces a cavity formed between the capacitor element and the exterior body. Effect of the Invention

[0011] According to the present disclosure, it is possible to improve heat dissipation while reducing weight. [Brief description of the drawings]

[0012] [Figure 1] 1A and 1B are perspective and exploded views of a capacitor according to an embodiment of the present disclosure. [Diagram 2] 2A and 2B are front and side sectional views of the capacitor shown in FIG. [Diagram 3] Fig. 3A is a schematic perspective view showing a process of producing a main body of a wound capacitor element, Fig. 3B is a schematic perspective view showing the main body of the same, and Fig. 3C is a schematic perspective view showing the same capacitor element. [Figure 4] Fig. 4A is a schematic perspective view showing a process of producing a main body of a multilayer capacitor element, Fig. 4B is a schematic perspective view showing the main body of the same, and Fig. 4C is a schematic perspective view showing the same capacitor element. [Diagram 5] Fig. 5A is a perspective view showing a bus bar fixed to an exterior body (cover) by insert molding, and Fig. 5B is a perspective view showing a capacitor element with a bus bar. [Figure 6]Fig. 6A is a perspective view showing a busbar-equipped capacitor element in which a resin coating is formed on a portion of the busbar and on the entire capacitor element, and Fig. 6B is a perspective view showing a busbar-equipped capacitor element in which a resin coating is formed on a portion of the busbar and on the end electrodes. [Figure 7] 7A and 7B are flow charts showing an example of a process for producing a capacitor element and a process for manufacturing a capacitor using the capacitor element, respectively. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] 1. Overview As described above, the metallized film capacitor of Patent Document 1 has a problem in that the weight of the entire capacitor tends to be large. In addition, the manufacturing method of the metallized film capacitor of Patent Document 1 also has a problem in that the productivity tends to be low.

[0014] On the other hand, the capacitor of Patent Document 2 has a problem in that the air present in the gap between the outer circumferential surface of the capacitor element and the inner circumferential surface of the exterior body can act as a heat insulating layer, which can reduce heat dissipation.

[0015] The present inventors have conducted extensive research to solve the above problems, and have developed the following capacitor 1. That is, in capacitor 1 according to this embodiment, as shown in Figures 1A to 2B, cavity 6 is not filled with resin. Therefore, the weight of capacitor 1 can be reduced.

[0016] In addition, in the capacitor 1 according to this embodiment, focusing on the fact that the infrared emissivity of resin is greater than that of metal, as shown in Figs. 1A to 2B and 6A, the resin coating film 5 is formed on the busbar 4 and the end electrode 25 present inside the exterior body 3, and is disposed so as to face the cavity 6. As a result, when the capacitor element 2 generates heat during energization of the capacitor 1, the heat is first transferred from the busbar 4 and the end electrode 25 to the resin coating film 5 by conduction, and then transferred from the resin coating film 5 by radiation through the cavity 6 to the exterior body 3. In other words, the cavity 6 is less likely to act as a heat insulating layer. Then, the heat is dissipated from the exterior body 3 to the outside. Therefore, the heat dissipation property of the capacitor 1 can be improved.

[0017] 2.Details (1) Capacitor A capacitor 1 (film capacitor) according to this embodiment will be described below mainly with reference to Figures 1A to 2B. Each figure is a schematic view, and the ratio of sizes and thicknesses of each component in each figure does not necessarily reflect the actual dimensional ratio.

[0018] The arrows indicating each direction in each figure (X-axis, Y-axis, and Z-axis perpendicular to each other) are not intended to define the direction of the capacitor 1 when it is used, but are merely depicted to make the explanation easier to understand, and have no substance. One side in the X-axis direction (positive direction) may be described as the "front", the other side in the X-axis direction (negative direction) as the "rear", one side in the Y-axis direction (positive direction) as the "right", the other side in the Y-axis direction (negative direction) as the "left", one side in the Z-axis direction (positive direction) as the "up" and the other side in the Z-axis direction (negative direction) as the "down". A view along the X-axis is called a "front view", a view along the Y-axis is called a "side view", and a view along the Z-axis is called a "planar view".

[0019] 1A and 1B show a capacitor 1 according to this embodiment. Capacitor 1 includes a capacitor element 2, a bus bar 4, and an exterior body 3. A resin coating film 5 is formed on at least a portion (end electrode 25) of capacitor element 2 and a portion of bus bar 4. In Figs. 1B, 6A, and 6B, the area where resin coating film 5 is formed is indicated by hatching. Below, the capacitor element 2, bus bar 4, resin coating film 5, and exterior body 3 will be described in order.

[0020] <Capacitor element> The capacitor element 2 has a main body portion 20 and an end electrode 25 .

[0021] The main body 20 is a rounded rectangular shape in a side view, and has a pair of end faces 200 and an outer peripheral surface 203 (see FIG. 3B). The pair of end faces 200 is a first end face 201 and a second end face 202. The first end face 201 is a surface facing the right side, and the second end face 202 is a surface facing the left side. In this manner, the first end face 201 and the second end face 202 are surfaces on opposite sides to each other. The outer peripheral surface 203 is a surface connecting the first end face 201 and the second end face 202. Specifically, the outer peripheral surface 203 connects the outer peripheral edge of the first end face 201 and the outer peripheral edge of the second end face 202.

[0022] The main body 20 is composed of a dielectric film 22 and a pair of electrodes 24 (a first electrode 241 and a second electrode 242) (see FIG. 3A). The details will be described in the section "(2) Manufacturing method of a capacitor", but the dielectric film 22 is a resin film. Inside the main body 20, the first electrode 241 and the second electrode 242 face each other via the dielectric film 22. At the first end surface 201 of the main body 20, the first electrode 241 is exposed in a spiral shape in a side view, and the second electrode 242 is not exposed. On the other hand, at the second end surface 202 of the main body 20, the second electrode 242 is exposed in a spiral shape in a side view, and the first electrode 241 is not exposed. The outer peripheral surface 203 of the main body 20 is made of resin. At the outer peripheral surface 203, the first electrode 241 and the second electrode 242 are not exposed.

[0023] The end surface electrode 25 is formed on the end surface 200 of the main body 20 (see FIG. 3C). Specifically, the end surface electrode 25 includes a first end surface electrode 251 and a second end surface electrode 252, where the first end surface electrode 251 is formed on the first end surface 201 and the second end surface electrode 252 is formed on the second end surface 202. The first end surface electrode 251 is connected to the first electrode 241 but is not connected to the second electrode 242. The second end surface electrode 252 is connected to the second electrode 242 but is not connected to the first electrode 241.

[0024] Busbars The bus bar 4 is a conductor capable of passing a large amount of current and is made of a metal including, for example, copper (Cu) and / or aluminum (Al).

[0025] The busbars 4 are connected to the end surface electrodes 25. Specifically, the busbars 4 include a first busbar 41 and a second busbar 42, the first busbar 41 is connected to the first end surface electrode 251, and the second busbar 42 is connected to the second end surface electrode 252.

[0026] The first busbar 41 has a first leg piece 413, a first flat portion 412, and a first protruding piece 411 (see FIG. 5B). The first leg piece 413 is a plate-like portion having an inverted U-shape in a side view, and is directly connected to the first end surface electrode 251 by soldering or the like. The first flat portion 412 protrudes leftward from the upper end of the first leg piece 413. The first flat portion 412 is a plate-like portion having a rectangular shape in a plan view, and extends in the front-rear direction. The first protruding piece 411 protrudes upward from the rear end of the first flat portion 412. The first protruding piece 411 is a plate-like portion having a rectangular shape in a front view, and extends in the up-down direction.

[0027] The second busbar 42 has a second leg piece 423, a second flat portion 422, and a second protruding piece 421 (see FIG. 5B). The second leg piece 423 is approximately the same shape and size as the first leg piece 413. The second leg piece 423 is a plate-like portion having an inverted U-shape in a side view, and is directly connected to the second end surface electrode 252 by soldering or the like. The second flat portion 422 protrudes from the upper end of the second leg piece 423 to the right. The second flat portion 422 is approximately the same shape and size as the first flat portion 412. The second flat portion 422 is a plate-like portion having a rectangular shape in a plan view, and extends in the front-rear direction. The second protruding piece 421 protrudes upward from the rear end of the second flat portion 422. The second protruding piece 421 is approximately the same shape and size as the first protruding piece 411. The second projecting piece 421 is a plate-like portion having a rectangular shape when viewed from the front, and extends in the vertical direction.

[0028] The busbar 4 is extended to the outside of the exterior body 3 (see FIG. 1A). Specifically, an upper portion of a first protruding piece 411 of the first busbar 41 is extended to the outside of the exterior body 3 (cover part 32 described below). Similarly, an upper portion of a second protruding piece 421 of the second busbar 42 is extended to the outside of the exterior body 3 (cover part 32 described below).

[0029] In this way, the busbar 4 has a portion that exists inside the exterior body 3 and a portion that exists outside the exterior body 3. Specifically, for the first busbar 41, the portion that exists inside the exterior body 3 is the lower portion of the first protruding piece 411, the first flat portion 412, and the first leg piece 413, and the portion that exists outside the exterior body 3 is the upper portion of the first protruding piece 411. Similarly, for the second busbar 42, the portion that exists inside the exterior body 3 is the lower portion of the second protruding piece 421, the second flat portion 422, and the second leg piece 423, and the portion that exists outside the exterior body 3 is the upper portion of the second protruding piece 421.

[0030] <Resin coating> The resin coating film 5 is used to utilize thermal radiation. The resin coating film 5 is formed on the end surface electrodes 25. Specifically, the resin coating film 5 is formed on the first end surface electrode 251 and the second end surface electrode 252 to cover them.

[0031] Generally, resin (plastic) has a higher infrared emissivity than metal. Therefore, when resin coating film 5 is formed on end electrode 25, heat inside end electrode 25 can be easily extracted to the outside of end electrode 25 through resin coating film 5.

[0032] Furthermore, the resin coating film 5 is formed on a portion of the busbar 4 that is present inside the exterior body 3. Specifically, for the first busbar 41, the resin coating film 5 is formed on and covers the lower portion of the first protruding piece 411, the first flat portion 412, and the first leg piece 413. For the second busbar 42, the resin coating film 5 is formed on and covers the lower portion of the second protruding piece 421, the second flat portion 422, and the second leg piece 423.

[0033] As described above, resin has a high infrared emissivity, so when resin coating film 5 is formed on busbar 4, heat within busbar 4 can be easily extracted to the outside of busbar 4 through resin coating film 5.

[0034] Since the outer peripheral surface 203 of the main body 20 is made of resin, it is not necessary to form a resin coating film 5 on the outer peripheral surface 203 (see the cross-hatched area in FIG. 6B), or the resin coating film 5 may also be formed on the outer peripheral surface 203 (see the cross-hatched area in FIG. 6A).

[0035] The material of the resin coating film 5 is not particularly limited as long as it has a higher infrared emissivity than metal, but examples include polyphenylene sulfide (PPS), epoxy resin (EP), polyethylene terephthalate (PET), polypropylene (PP), acrylic resin, etc.

[0036] The thickness of the resin coating film 5 is not particularly limited as long as it is a thickness that allows the use of thermal radiation. The lower limit of the thickness of the resin coating film 5 is preferably 1 μm or more, more preferably 3 μm or more, and even more preferably 15 μm or more. On the other hand, the upper limit of the thickness of the resin coating film 5 is preferably 1000 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0037] <Exterior body> The exterior body 3 houses the capacitor element 2. The material of the exterior body 3 is not particularly limited, but may be, for example, polyphenylene sulfide (PPS), epoxy resin (EP), etc. The exterior body 3 has a housing 31 and a cover portion 32.

[0038] The housing 31 is open at the top. The housing 31 has a bottom plate 311 and a peripheral wall 312. The bottom plate 311 is a plate-like portion having a rectangular shape in a plan view. The peripheral wall 312 protrudes upward from the outer periphery of the bottom plate 311. The peripheral wall 312 is composed of a front wall located at the front, a rear wall located at the rear, a right wall located on the right side, and a left wall located on the left side. The space surrounded by the bottom plate 311 and the peripheral wall 312 forms the accommodation section 310. The capacitor element 2 is accommodated in the accommodation section 310.

[0039] The cover part 32 is a member that covers the opening of the housing 31. The cover part 32 is a plate-like part that is rectangular in a plan view. When the opening of the housing 31 is covered with the cover part 32, the storage part 310 is sealed. The cover part 32 is joined to the housing 31 by an appropriate means such as welding.

[0040] The cover portion 32 has a plurality of through holes 33 (two in this embodiment). The through holes 33 penetrate in the up-down direction. The through holes 33 are used to pull out a portion of the bus bar 4 from inside to outside the exterior body 3. Specifically, the first protruding piece 411 of the first bus bar 41 penetrates through the through hole 33 on the right side, and an upper portion of the first protruding piece 411 is pulled out to the outside of the exterior body 3. On the other hand, the second protruding piece 421 of the second bus bar 42 penetrates through the through hole 33 on the left side, and an upper portion of the second protruding piece 421 is pulled out to the outside of the exterior body 3.

[0041] The portion where the busbar 4 penetrates from the inside to the outside of the exterior body 3 is blocked by a blocking member 34 (see FIGS. 1A and 2B). In this manner, the blocking member 34 blocks a small gap between the inner circumferential surface of the through hole 33 and the outer circumferential surface of the busbar 4 (first protruding piece 411 and second protruding piece 421). The blocking member 34 is, for example, an adhesive.

[0042] As shown in Fig. 5A, the bus bar 4 may be fixed to the exterior body 3 by insert molding. When insert molding is used, the blocking member 34 is not necessary, but in Fig. 5A, the blocking member 34 is used to eliminate a small gap between different materials (metal and resin).

[0043] As described above, capacitor element 2 is accommodated in accommodation portion 310. The cavity 6 is formed by the space in accommodation portion 310 other than the portion occupied by capacitor element 2. As shown in Fig. 2A and Fig. 2B, cavity 6 is formed between capacitor element 2 and exterior body 3. Resin coating film 5 faces cavity 6.

[0044] That is, the resin coating film 5 formed on the end electrode 25 faces the cavity 6 existing between the capacitor element 2 and the peripheral wall 312 (see FIG. 2A). Specifically, the resin coating film 5 formed on the first end electrode 251 faces the cavity 6 existing between the first end electrode 251 and the peripheral wall 312 (right wall). On the other hand, the resin coating film 5 formed on the second end electrode 252 faces the cavity 6 existing between the second end electrode 252 and the peripheral wall 312 (left wall).

[0045] Furthermore, the resin coating film 5 formed on the busbar 4 faces the cavity 6 existing between the capacitor element 2 and the cover portion 32, and the cavity 6 existing between the capacitor element 2 and the peripheral wall 312 (see FIG. 2B). Specifically, for the first busbar 41, the resin coating film 5 formed on the lower portion of the first protruding piece 411 and the first flat portion 412 faces the cavity 6 existing between the capacitor element 2 and the cover portion 32, and the resin coating film 5 formed on the first leg piece 413 faces the cavity 6 existing between the capacitor element 2 and the peripheral wall 312 (right wall). On the other hand, for the second busbar 42, the resin coating film 5 formed on the lower portion of the second protruding piece 421 and the second flat portion 422 faces the cavity 6 existing between the capacitor element 2 and the cover portion 32, and the resin coating film 5 formed on the second leg piece 423 faces the cavity 6 existing between the capacitor element 2 and the peripheral wall 312 (left wall).

[0046] <Action and effect> In this embodiment, by passing current through a first bus bar 41 and a second bus bar 42 that are present on the outside of the exterior body 3, the capacitor 1 can be charged or discharged.

[0047] According to the embodiment, the heat dissipation performance of the capacitor 1 can be improved while reducing the weight of the capacitor 1.

[0048] That is, in this embodiment, resin is not filled into cavity 6. Therefore, compared to the metallized film capacitor of Patent Document 1, for example, capacitor 1 can be made lighter in weight.

[0049] In this embodiment, the resin coating film 5 is formed on the busbar 4 and the end electrode 25 present inside the exterior body 3, and faces the cavity 6. The infrared emissivity of the resin coating film 5 is greater than that of the busbar 4 and the end electrode 25. Therefore, when the capacitor element 2 generates heat during energization of the capacitor 1, the heat first moves from the busbar 4 and the end electrode 25 to the resin coating film 5 by conduction, and then moves from the resin coating film 5 through the cavity 6 by radiation to the exterior body 3. In this way, since the thermal radiation (thermal radiation) of the resin coating film 5 is utilized, the cavity 6 is less likely to act as a heat insulating layer. Then, the heat is dissipated from the exterior body 3 to the outside. Therefore, the heat dissipation of the capacitor 1 can be improved. Note that, as shown in FIG. 6B, even if the resin coating film 5 is not formed on the outer peripheral surface 203 of the capacitor element 2, the outer peripheral surface 203 is made of resin, and therefore thermal radiation can be utilized in the same manner as the resin coating film 5.

[0050] Furthermore, in this embodiment, the portion where the bus bar 4 penetrates from the inside to the outside of the exterior body 3 is blocked by the blocking member 34, so that the sealed state of the exterior body 3 can be stably maintained.

[0051] Furthermore, if busbar 4 is fixed to exterior body 3 (cover portion 32 in this embodiment) by insert molding, busbar 4 can be easily installed, which tends to improve workability.

[0052] (2) Capacitor manufacturing method Next, a method for manufacturing capacitor 1 (film capacitor) according to this embodiment will be described mainly with reference to Figures 3A to 7B. The method for manufacturing capacitor 1 is roughly divided into producing capacitor element 2 and housing capacitor element 2 in exterior body 3.

[0053] <Preparation of capacitor element> The production of capacitor element 2 includes an element body forming step, a pressurizing step, and an end surface electrode forming step (see FIG. 7A). Note that the production of capacitor element 2 does not necessarily have to include the pressurizing step.

[0054] <Element body forming process> 3A, two elongated metallized films 21 (first metallized film 211 and second metallized film 212) are stacked and wound around axis C extending in the left-right direction to form cylindrical main body 20. First electrode 241 and second electrode 242 face each other via dielectric film 22 along the radial direction of an imaginary circle centered on axis C.

[0055] Here, a description will be given of first metallized film 211 and second metallized film 212 used to form main body portion 20. Note that metallized film 21 is a general term for first metallized film 211 and second metallized film 212.

[0056] First metallized film 211 extends in the front-rear direction, has a constant width in the left-right direction, and has a constant thickness in the up-down direction. First metallized film 211 includes first dielectric film 221 and first electrode 241.

[0057] The first dielectric film 221 is a film made of a dielectric material (resin). The material of the first dielectric film 221 is not particularly limited, but examples thereof include polypropylene (PP) and polyethylene terephthalate (PET).

[0058] The first dielectric film 221 extends in the front-rear direction, has a constant width in the left-right direction, and has a constant thickness in the up-down direction. The thickness of the first dielectric film 221 is not particularly limited, but is, for example, 1.0 μm or more and 10.0 μm or less.

[0059] The first electrode 241 is formed on one surface (top surface) of the first dielectric film 221. Specifically, the first electrode 241 is formed in a solid shape on the top surface of the first dielectric film 221 except for the first margin portion 231. The first margin portion 231 is present at the left end of the top surface of the first dielectric film 221 and is a thin strip-shaped portion extending in the front-rear direction. In FIG. 3A, the first electrode 241 is shown by a dot pattern.

[0060] The first electrode 241 may be any of a vapor deposition electrode, a metal foil electrode, and a plated electrode. The material of the first electrode 241 is not particularly limited, but may be, for example, aluminum (Al), magnesium (Mg), or an alloy thereof. The thickness of the first electrode 241 is not particularly limited, but may be, for example, 5 nm or more and 100 nm or less.

[0061] Meanwhile, second metallized film 212 has the same shape and size as first metallized film 211. Second metallized film 212 has second dielectric film 222 and second electrode 242.

[0062] The second dielectric film 222 has the same shape and size as the first dielectric film 221. The material of the second dielectric film 222 is the same as the material of the first dielectric film 221.

[0063] The second electrode 242 is formed on one surface (top surface) of the second dielectric film 222. Specifically, the second electrode 242 is formed in a solid manner on the top surface of the second dielectric film 222 except for the second margin portion 232. The second margin portion 232 is a thin strip-shaped portion that exists at the right end of the top surface of the second dielectric film 222 and extends in the front-rear direction. In FIG. 3A, the second electrode 242 is shown by a dot pattern.

[0064] The second electrode 242 may be any one of a vapor deposition electrode, a metal foil electrode, and a plated electrode, similar to the first electrode 241. The material and thickness of the second electrode 242 are the same as those of the first electrode 241.

[0065] It is to be noted that dielectric film 22 is a general term for first dielectric film 221 and second dielectric film 222, electrode 24 is a general term for first electrode 241 and second electrode 242, and margin portion 23 is a general term for first margin portion 231 and second margin portion 232.

[0066] <Pressure application process> Next, the cylindrical body portion 20 shown in Fig. 3A is pressurized and flattened to obtain the flattened cylindrical body portion 20 shown in Fig. 3B. In this embodiment, the cylindrical body portion 20 is pressurized in the vertical direction to obtain the flattened cylindrical body portion 20.

[0067] <<End face electrode formation process>> Next, the end surface electrode 25 is formed on the end surface 200 of the main body 20. Specifically, the first end surface 201 is sprayed with metal to form the first end surface electrode 251. As a result, the first end surface electrode 251 is electrically connected to the first electrode 241. The thickness of the first end surface electrode 251 is not particularly limited, but is, for example, 0.5 mm or more and 1.5 mm or less. On the other hand, the second end surface 202 is sprayed with metal to form the second end surface electrode 252. As a result, the second end surface electrode 252 is electrically connected to the second electrode 242. The thickness of the second end surface electrode 252 is the same as the thickness of the first end surface electrode 251.

[0068] The metal to be sprayed is not particularly limited, but examples thereof include zinc (Zn), tin (Sn), and alloys thereof.

[0069] When the end electrode formation step is completed, capacitor element 2 shown in FIG. 3C is obtained.

[0070] <Enclosing the capacitor element in the exterior body> The process of housing capacitor element 2 in exterior housing 3 includes a bus bar attachment step, a resin coating step, and an element sealing step (see FIG. 7B).

[0071] <Busbar installation process> First, as shown in Fig. 5B, the busbar 4 is attached to the capacitor element 2. Specifically, the first leg piece 413 of the first busbar 41 is connected to the first end electrode 251 of the capacitor element 2 by soldering or the like. This electrically connects the first busbar 41 and the first end electrode 251. Meanwhile, the second leg piece 423 of the second busbar 42 is connected to the second end electrode 252 of the capacitor element 2 by soldering or the like. This electrically connects the second busbar 42 and the second end electrode 252. In this manner, a capacitor element 26 with a busbar is obtained.

[0072] <Resin coating process> Next, a part of the busbar-equipped capacitor element 26 shown in FIG. 5B is coated with resin (FIG. 6A). Specifically, the busbar 4 (the upper part of the first protruding piece 411 and the second protruding piece 421) of the busbar-equipped capacitor element 26 is pinched and lifted, and the busbar-equipped capacitor element 26 is immersed in a resin vat containing liquid resin. As a result, the busbar-equipped capacitor element 26 is coated with resin except for the upper part of the first protruding piece 411 and the second protruding piece 421. Thereafter, the busbar-equipped capacitor element 26 is lifted from the resin vat, and the resin is cured or solidified to form a resin coating film 5 as shown in FIG. 6A. If the surface of the resin coating film 5 is roughened, it may be possible to further increase the infrared emissivity. In addition to the above means, other appropriate means such as powder coating and electrostatic coating can be used as a means for coating with resin.

[0073] Since the outer peripheral surface 203 of the main body 20 is made of resin, if the resin can be easily applied in different layers, it is not necessary to form the resin coating film 5 on the outer peripheral surface 203 from the viewpoint of saving resin (see FIG. 6B).

[0074] <Element sealing process> Next, the busbar-equipped capacitor element 26 on which the resin coating film 5 is formed is housed in the exterior body 3 and sealed (see FIGS. 1A and 1B). Specifically, first, the busbar-equipped capacitor element 26 is housed in the housing portion 310 of the housing 31. Next, the opening of the housing 31 is covered with the cover portion 32 to seal the housing portion 310. At this time, the first protruding piece 411 of the first busbar 41 and the second protruding piece 421 of the second busbar 42 are caused to penetrate the through-hole 33 of the cover portion 32 from below to above. Thereafter, the cover portion 32 is joined to the housing 31 by an appropriate means such as welding. If necessary, the portion where the busbar 4 penetrates from the inside to the outside of the exterior body 3 is blocked with a blocking member 34 such as an adhesive.

[0075] When the device sealing process is completed, the capacitor 1 shown in FIG. 1A is obtained.

[0076] <Action and effect> According to this embodiment, it is possible to easily manufacture a capacitor 1 that is lightweight and has excellent heat dissipation properties. Furthermore, according to this embodiment, it is also possible to improve productivity compared to the manufacturing method of the metallized film capacitor of Patent Document 1. That is, in Patent Document 1, it takes several hours (e.g., 6 to 8 hours) for the filled resin to harden, which tends to reduce the productivity of the metallized film capacitor. In contrast, in this embodiment, it is possible to form the resin coating film 5 in a short time (e.g., about 15 minutes), which shortens the time required to manufacture the capacitor 1.

[0077] 3. Variations In this embodiment, the capacitor 1 is a film capacitor, but the capacitor 1 may be, for example, an aluminum electrolytic capacitor, a ceramic capacitor, an electric double layer capacitor, or the like.

[0078] In this embodiment, the case where capacitor element 2 is a wound type has been described, but capacitor element 2 may be a laminated type. In laminated capacitor element 2, first metallized films 211 and second metallized films 212 are laminated alternately in the vertical direction (see FIG. 4A). As a result, first electrode 241 and second electrode 242 face each other in the vertical direction with dielectric film 22 interposed therebetween. Main body 20 has a rectangular parallelepiped shape (see FIG. 4B). When first end surface electrode 251 is formed on first end surface 201 of main body 20 and second end surface electrode 252 is formed on second end surface 202 of main body 20, capacitor element 2 having a rectangular parallelepiped shape as shown in FIG. 4C is obtained.

[0079] 4. Aspects As is apparent from the above-described embodiment and modified examples, the present disclosure includes the following aspects. In the following, reference symbols are given in parentheses only to clarify the correspondence with the embodiment.

[0080] The first aspect is a capacitor (1) comprising a capacitor element (2) having an end electrode (25), an exterior body (3) that houses the capacitor element (2), and a bus bar (4) that is connected to the end electrode (25) and extended to the outside of the exterior body (3). A resin coating film (5) is formed on the bus bar (4) and / or the end electrode (25) that are present inside the exterior body (3). The resin coating film (5) faces a cavity (6) formed between the capacitor element (2) and the exterior body (3).

[0081] According to this aspect, it is possible to improve heat dissipation while reducing the weight.

[0082] The second aspect is the capacitor (1) based on the first aspect. In the second aspect, a portion where the bus bar (4) penetrates from the inside to the outside of the exterior body (3) is blocked by a blocking member (34).

[0083] According to this embodiment, the sealed state of the exterior body (3) can be stably maintained.

[0084] A third aspect is the capacitor (1) based on the first or second aspect. In the third aspect, the bus bar (4) is fixed to the exterior body (3) by insert molding.

[0085] According to this embodiment, the bus bar (4) can be easily installed, which makes it easy to improve workability.

[0086] A fourth aspect is a method for manufacturing a capacitor (1), the method comprising: a capacitor element (2) having an end electrode (25); an exterior body (3) that houses the capacitor element (2); and a bus bar (4) that is connected to the end electrode (25) and extended to the outside of the exterior body (3). The method includes the steps of forming a resin coating film (5) on the bus bar (4) and / or the end electrode (25) that will be present inside the exterior body (3); and housing the capacitor element (2) in the exterior body (3) such that the resin coating film (5) faces a cavity (6) formed between the capacitor element (2) and the exterior body (3).

[0087] According to this embodiment, it is possible to improve heat dissipation while reducing the weight. Furthermore, the resin coating film (5) can be formed in a short time compared to the case where the resin is filled inside the exterior body (3) and then cured, so that the productivity can be improved. [Explanation of symbols]

[0088] 1 Capacitor 2. Capacitor elements 25 End electrode 3 Exterior body 4 Busbars 5 Resin coating 6 cavities

Claims

1. a capacitor element having an end electrode, an exterior body that houses the capacitor element, and a bus bar that is connected to the end electrode and extended to the outside of the exterior body, a resin coating film is formed on the bus bar and / or the end electrode present inside the exterior body, the resin coating film faces a cavity formed between the capacitor element and the exterior body; Capacitor.

2. a portion where the bus bar penetrates from the inside to the outside of the exterior body is blocked by a blocking member; The capacitor of claim 1 .

3. The bus bar is fixed to the exterior body by insert molding. The capacitor according to claim 1 or 2.

4. A method for manufacturing a capacitor including a capacitor element having an end electrode, an exterior body that houses the capacitor element, and a bus bar that is connected to the end electrode and extended to an outside of the exterior body, comprising the steps of: forming a resin coating film on the bus bar and / or the end electrode that will be present inside the exterior body; and housing the capacitor element in the exterior body so that the resin coating film faces a cavity formed between the capacitor element and the exterior body. How a capacitor is manufactured.

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