Capacitor and method for manufacturing the same

Abstract

Provided is a capacitor that is lightweight yet can reduce moisture absorption. The capacitor comprises a capacitor element and a protective film. The capacitor element has a first end-face electrode, a second end-face electrode, and an outer peripheral surface. The second end-face electrode exists at the side opposite to the first end-face electrode. The outer peripheral surface exists between the first end-face electrode and the second end-face electrode. The protective film has a first protective part, a second protective part, and a third protective part. The first protective part protects the peripheral edge part of the first end-face electrode. The second protective part protects the peripheral edge part of the second end-face electrode. The third protective part is connected to the first protective part and the second protective part, and protects the outer peripheral surface.

Description

Technical Field

[0001] The present disclosure generally relates to a capacitor and a method for manufacturing the same, and more particularly to a capacitor including a capacitor element and a method for manufacturing the same.

Background Art

[0002] Patent Document 1 discloses a case-molded capacitor. This case-molded capacitor connects a plurality of capacitor elements with a bus bar provided with a terminal portion for external connection at one end, houses this in a case, and resin-molds it except for the terminal portion of at least the bus bar. The mold resin for performing the resin molding is mainly an epoxy resin, to which 3 to 25 wt% of hollow spherical inorganic substances are added.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The case-molded capacitor of Patent Document 1 includes a case and a mold resin filled in the case, and reduces moisture absorption at the sacrifice of weight reduction.

[0005] An object of the present disclosure is to provide a capacitor that can reduce moisture absorption while being lightweight, and a method for manufacturing a capacitor capable of manufacturing such a capacitor.

Means for Solving the Problems

[0006] A capacitor according to one aspect of the present disclosure comprises a capacitor element and a protective film. The capacitor element has a first end face electrode, a second end face electrode, and an outer circumferential surface. The second end face electrode is located on the opposite side of the first end face electrode. The outer circumferential surface is located between the first end face electrode and the second end face electrode. The protective film has a first protective portion, a second protective portion, and a third protective portion. The first protective portion protects the peripheral edge of the first end face electrode. The second protective portion protects the peripheral edge of the second end face electrode. The third protective portion is connected to the first and second protective portions and protects the outer circumferential surface.

[0007] A method for manufacturing a capacitor according to one aspect of the present disclosure includes a preparation step, a winding step, and a fusion step. In the preparation step, a capacitor element is prepared having a first end face electrode, a second end face electrode located on the opposite side of the first end face electrode, and an outer circumferential surface located between the first end face electrode and the second end face electrode. In the winding step, a protective film having a width longer than the distance between the first end face electrode and the second end face electrode is wound around the outer circumferential surface of the capacitor element, allowing it to extend beyond both ends of the capacitor element. In the fusion step, a first protruding portion of the protective film extending from the first end face electrode side is bent toward the first end face electrode and fused to form a first protective portion that protects the peripheral edge of the first end face electrode, and a second protruding portion of the protective film extending from the second end face electrode side is bent toward the second end face electrode and fused to form a second protective portion that protects the peripheral edge of the second end face electrode. [Effects of the Invention]

[0008] According to the capacitor of this disclosure, it is possible to reduce moisture absorption while maintaining a lightweight design.

[0009] According to the capacitor manufacturing method of this disclosure, it is possible to manufacture a lightweight capacitor with excellent moisture resistance. [Brief explanation of the drawing]

[0010] [Figure 1]Figure 1 is a perspective view showing a capacitor according to the first embodiment. [Figure 2] Figure 2A is a schematic cross-sectional view showing the same capacitor. Figure 2B is an enlarged view of the area enclosed by the dashed line in Figure 2A. [Figure 3] Figures 3A to 3D are schematic cross-sectional views showing the manufacturing process of the capacitors mentioned above. [Figure 4] Figure 4 is a perspective view showing a capacitor according to the second embodiment. [Figure 5] Figure 5A is a schematic cross-sectional view showing the same capacitor. Figure 5B is an enlarged view of the area enclosed by the dashed line in Figure 5A. [Figure 6] Figures 6A and 6B are schematic cross-sectional views showing the manufacturing process of the capacitor mentioned above. [Modes for carrying out the invention]

[0011] 1. Overview The inventors investigated the pathways through which moisture could penetrate the interior of a capacitor element, assuming that the case and the molding resin filled inside the case were removed from the case-molded capacitor described in Patent Document 1. As a result, they found that moisture easily penetrates from the boundary between the end face of the metallized film winding and the metallized electrode. Therefore, the inventors furthered their research, assuming that the case would not be used, and as a result, developed the following capacitor 1.

[0012] In other words, the capacitor 1 according to this embodiment comprises a capacitor element 2 and a protective film 5, as shown in Figure 1.

[0013] As shown in Figure 2A, the capacitor element 2 has a first end face electrode 41, a second end face electrode 42, and an outer circumferential surface 20. The second end face electrode 42 is located on the opposite side of the first end face electrode 41. The outer circumferential surface 20 is located between the first end face electrode 41 and the second end face electrode 42.

[0014] As shown in FIG. 2A, the protective film 5 has a first protective portion 51, a second protective portion 52, and a third protective portion 53. The first protective portion 51 protects the peripheral portion of the first end face electrode 41. The second protective portion 52 protects the peripheral portion of the second end face electrode 42. The third protective portion 53 is connected to the first protective portion 51 and the second protective portion 52 and protects the outer peripheral surface 20.

[0015] As shown in FIG. 2B, in the present embodiment, the boundary portion X1 between the main body 3 of the capacitor element 2 and the first end face electrode 41 is covered by the protective film 5 (particularly the third protective portion 53). Thereby, it is possible to suppress moisture from entering the inside of the main body 3 of the capacitor element 2 from the boundary portion X1.

[0016] In the present embodiment, there is a boundary portion X2 between the first end face electrode 41 and the protective film 5 (particularly the first protective portion 51), but the path from the boundary portion X2 to the boundary portion X1 is bent. Therefore, even if moisture enters from the boundary portion X2, it is difficult to reach the boundary portion X1. The same applies to the second end face electrode 42 side. Moreover, the capacitor 1 does not require a case.

[0017] Therefore, according to the present embodiment, it is possible to reduce moisture absorption while being lightweight.

[0018] 2. Details (1) First Embodiment (1.1) Capacitor Hereinafter, the capacitor 1 according to the first embodiment will be described with reference to the drawings. For the convenience of explaining the positional relationship and the like, arrows indicating the X-axis, Y-axis, and Z-axis constituting a three-dimensional orthogonal coordinate system are shown in the drawings, but these arrows do not accompany an entity. Hereinafter, the XY plane view means the case of viewing along the Z-axis direction, the YZ plane view means the case of viewing along the X-axis direction, and the ZX plane view means the case of viewing along the Y-axis direction, respectively. The directions of the X-axis, Y-axis, and Z-axis are merely examples and are not intended to limit the directions during the manufacture and use of the capacitor 1.

[0019] FIG. 1, FIGS. 2A and 2B show a capacitor 1 according to the present embodiment. The capacitor 1 is a so-called case-less capacitor. That is, unlike the case-molded capacitor of Patent Document 1, the capacitor 1 does not require a case. Thereby, the weight of the capacitor 1 can be reduced.

[0020] The capacitor 1 includes a capacitor element 2 and a protective film 5. The capacitor 1 may further include a bus bar 7 and a sealing portion 8.

[0021] <Capacitor Element> First, the capacitor element 2 will be described. The capacitor element 2 of the present embodiment is a so-called wound-type capacitor element. The capacitor element 2 has a main body 3, a first end face electrode 41, and a second end face electrode 42 (see FIG. 2A).

[0022] The main body 3 has two end faces (the face facing the positive direction of the X axis and the face facing the negative direction of the X axis) and an outer peripheral surface 20 existing between these two end faces. Specifically, the main body 3 is formed by overlapping two metallized films obtained by vapor-depositing a metal such as aluminum on a dielectric film, winding the thus-overlapped metallized films, and pressing them flatly (pressing in the Y-axis direction). The cross-sectional shape of the main body 3 in a YZ plane view is a rounded rectangle that is longer in the Z-axis direction than in the Y-axis direction. The main body 3 has a columnar shape extending in the X-axis direction.

[0023] The first end face electrode 41 and the second end face electrode 42 are provided in layers on the two end faces of the main body 3, respectively. Thus, the capacitor element 2 has the first end face electrode 41, the second end face electrode 42, and the outer peripheral surface 20. The cross-sectional shape of the capacitor element 2 in a YZ plane view is also a rounded rectangle that is longer in the Z-axis direction than in the Y-axis direction, similar to the main body 3 (see FIG. 1). The capacitor element 2 also has a columnar shape extending in the X-axis direction, similar to the main body 3.

[0024] The first end electrode 41 is located on the surface of the capacitor element 2 facing the positive X-axis direction. The first end electrode 41 is formed of a metal such as zinc by, for example, metal spraying.

[0025] The second end electrode 42 is located on the opposite side of the first end electrode 41. That is, the second end electrode 42 is located on the side of the capacitor element 2 facing the negative X-axis direction. The second end electrode 42 is formed in the same way as the first end electrode 41.

[0026] The outer circumferential surface 20 of the capacitor element 2 is the surface that constitutes the outer periphery of the capacitor element 2. The outer circumferential surface 20 includes the outer circumferential surface 20 of the main body 3 and is located between the first end electrode 41 and the second end electrode 42.

[0027] <Protective film> Next, the protective film 5 will be described. The protective film 5 is an electrically insulating film. Preferably, the protective film 5 is a film that is impermeable to moisture and can be fused. Specifically, the material of the protective film 5 is not particularly limited, but examples include polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC).

[0028] The protective film 5 has a first protective section 51, a second protective section 52, and a third protective section 53.

[0029] The first protective portion 51 covers and protects a part of the first end face electrode 41. In particular, the first protective portion 51 includes a portion that protects the peripheral edge of the first end face electrode 41. The first protective portion 51 is annular in shape (see Figure 1). Specifically, the outer edge of the first protective portion 51 forms a rounded rectangle that is longer in the Z-axis direction than in the Y-axis direction when viewed in the YZ plane. The inner edge of the first protective portion 51 forms a rounded rectangle that is slightly smaller than the rounded rectangle formed by the outer edge of the first protective portion 51. The portion between the outer edge and the inner edge of the first protective portion 51 corresponds to the peripheral edge of the first end face electrode 41.

[0030] The second protective portion 52 covers and protects a part of the second end face electrode 42. In particular, the second protective portion 52 includes a portion that protects the peripheral edge of the second end face electrode 42. The second protective portion 52 is the same as the first protective portion 51. That is, the second protective portion 52 is also annular in shape. Specifically, the outer edge of the second protective portion 52 forms a rounded rectangle that is longer in the Z-axis direction than in the Y-axis direction when viewed in the YZ plane. The inner edge of the second protective portion 52 forms a rounded rectangle that is slightly smaller than the rounded rectangle formed by the outer edge of the second protective portion 52. The portion between the outer edge and the inner edge of the second protective portion 52 corresponds to the peripheral edge of the second end face electrode 42.

[0031] The third protective portion 53 is connected to the first protective portion 51 and the second protective portion 52 and includes a portion that protects the outer circumferential surface 20. The third protective portion 53 is cylindrical in shape. One opening edge of the third protective portion 53 (the positive X-axis side) is connected to the outer circumferential surface of the first protective portion 51. The other opening edge of the third protective portion 53 (the negative X-axis side) is connected to the outer circumferential surface of the second protective portion 52. The third protective portion 53 covers and protects the outer circumferential surface 20 of the capacitor element 2.

[0032] The protective film 5 includes a fused portion 50. The fused portion 50 is a part that is bonded by applying pressure after heating. In other words, fusion is synonymous with welding.

[0033] In this embodiment, the fused portion 50 is present on the entire inner surface (the surface facing the negative X-axis direction) of the first protective portion 51 and on the entire inner surface (the surface facing the positive X-axis direction) of the second protective portion 52. The fused portion 50 is bonded to the first end electrode 41 and the second end electrode 42. That is, the entire inner surface of the first protective portion 51 is bonded to the periphery of the first end electrode 41, and the entire inner surface of the second protective portion 52 is bonded to the periphery of the second end electrode 42.

[0034] <Bus bar> The busbar 7 is a conductive member (metal member). The busbar 7 has an L-shape in a ZX plan view. The busbar 7 includes a first busbar 71 and a second busbar 72.

[0035] The first busbar 71 is electrically connected to the first end face electrode 41. Specifically, the first busbar 71 is electrically connected to the surface of the first end face electrode 41 that is not protected by the first protective portion 51 (the surface surrounded by the inner periphery of the first protective portion 51).

[0036] The second busbar 72 is electrically connected to the second end face electrode 42. Specifically, the second busbar 72 is electrically connected to the surface of the second end face electrode 42 that is not protected by the second protective portion 52 (the surface surrounded by the inner periphery of the second protective portion 52).

[0037] <Sealing part> The sealing portion 8 is an electrically insulating material. Preferably, the sealing portion 8 is a material that does not easily allow moisture to pass through. Specifically, the sealing material used to form the sealing portion 8 is not particularly limited, but examples include epoxy resin.

[0038] The sealing portion 8 seals the entire capacitor element 2. In this embodiment, the sealing portion 8 is a rectangular parallelepiped. A first busbar 71 protrudes from one end face of the sealing portion 8 (the face facing the positive X-axis direction). A second busbar 72 protrudes from the other end face of the sealing portion 8 (the face facing the negative X-axis direction).

[0039] (1.2) Manufacturing method Next, the method for manufacturing the capacitor 1 according to this embodiment will be described with reference to the drawings. The method for manufacturing the capacitor 1 according to this embodiment includes a preparation step, a winding step, and a fusion bonding step. The method for manufacturing the capacitor 1 may further include a busbar connection step and a sealing step.

[0040] <Preparation process> In the preparation step, the capacitor element 2 is prepared as shown in Figure 3A. As described above, the capacitor element 2 has a first end electrode 41, a second end electrode 42, and an outer circumferential surface 20. Let D be the length of the capacitor element 2 in the X-axis direction (that is, the distance between the first end electrode 41 and the second end electrode 42, more specifically, the distance in the X-axis direction between the face of the first end electrode 41 facing the positive X-axis direction and the face of the second end electrode 42 facing the negative X-axis direction).

[0041] <Winding process> In the winding process, as shown in Figure 3B, the protective film 5 is wound around the outer surface 20 of the capacitor element 2, centered on the line CL connecting the first end electrode 41 and the second end electrode 42. The line CL connecting the first end electrode 41 and the second end electrode 42 is a virtual straight line parallel to the X-axis. As described above, the protective film 5 is a single film before being wound.

[0042] The protective film 5 has a first overhang 510, a second overhang 520, and a third protective portion 53.

[0043] The first protruding portion 510 is connected to one side edge (the positive X-axis side) of the third protective portion 53. When the protective film 5 is wound around the capacitor element 2, the first protruding portion 510 is the portion of the protective film 5 that extends beyond the first end face electrode 41 side of the capacitor element 2. In the post-winding process (fusion process), the first protruding portion 510 becomes the first protective portion 51.

[0044] The second protruding portion 520 is connected to the other side edge (negative X-axis side) of the third protective portion 53. When the protective film 5 is wound around the capacitor element 2, the second protruding portion 520 is the portion of the protective film 5 that extends beyond the second end face electrode 42 side of the capacitor element 2. In the post-winding process (fusion process), the second protruding portion 520 becomes the second protective portion 52.

[0045] The protective film 5 has a width W (see Figure 3B). The width W is longer than the length D in the X-axis direction of the capacitor element 2 (the distance D between the first end electrode 41 and the second end electrode 42). The difference between the width W and the distance D is equal to the sum of the lengths in the X-axis direction of the first overhang 510 and the second overhang 520.

[0046] In the winding process, as shown in Figure 3B, the protective film 5 is wound around the outer surface 20 of the capacitor element 2, allowing it to protrude from both ends of the capacitor element 2 (the positive and negative ends of the X-axis). Specifically, the first protruding portion 510 protrudes from the positive end of the X-axis of the capacitor element 2. The second protruding portion 520 protrudes from the negative end of the X-axis of the capacitor element 2. The third protective portion 53 is placed on the outer surface 20 of the capacitor element 2 and does not protrude from either end of the capacitor element 2.

[0047] By winding the protective film 5 around the outer surface 20 of the capacitor element 2, the protective film 5 is stacked radially outward from the virtual circle in the YZ plane centered on the virtual straight line CL. As a result, the first overhang 510 protrudes cylindrically from one end of the capacitor element 2 in the positive X-axis direction. Similarly, the second overhang 520 protrudes cylindrically from the other end of the capacitor element 2 in the negative X-axis direction.

[0048] The number of turns of the protective film 5 is at least one, but is not particularly limited. The number of turns is determined appropriately considering the thickness of the protective film 5, etc.

[0049] <Fusing process> In the fusion process, as shown in Figure 3C, the first protruding portion 510 is bent toward the first end face electrode 41 and fused to form the first protective portion 51. Fusion (welding) includes heat welding, hot plate welding, ultrasonic welding, and laser welding.

[0050] Similarly, the second protruding portion 520 is bent toward the second end face electrode 42 and fused to form the second protective portion 52.

[0051] The capacitor 1 according to this embodiment is manufactured through the above process. The following steps are optional.

[0052] <Busbar connection process> In the busbar connection process, as shown in Figure 3D, the busbars 7 are connected to the capacitor 1. Specifically, the first busbar 71 is electrically connected to the surface of the first end face electrode 41 that is not protected by the first protective part 51. Furthermore, the second busbar 72 is electrically connected to the surface of the second end face electrode 42 that is not protected by the second protective part 52. The method of connecting the busbars 7 to the capacitor 1 is not particularly limited, but examples include welding and soldering.

[0053] <Sealing process> In the sealing process, the capacitor 1 to which the busbar 7 is connected is sealed with resin. That is, the capacitor element 2 is placed in a suitable mold, and a sealing material (for example, a thermosetting resin) is injected around the entire area of ​​the capacitor element 2 to form a sealing portion 8. This produces the capacitor 1 shown in Figure 1. Note that the sealing portion 8 is shown with dashed lines in Figure 1.

[0054] (1.3) Effects In this embodiment, as shown in Figure 2B, the boundary portion X1 between the main body 3 of the capacitor element 2 and the first end face electrode 41 is covered by a protective film 5 (particularly the third protective portion 53). This prevents moisture from entering the interior of the main body 3 of the capacitor element 2 from the boundary portion X1.

[0055] In this embodiment, a boundary portion X2 exists between the first end electrode 41 and the protective film 5 (particularly the first protective portion 51), but a fusion portion 50 exists in the path from boundary portion X2 to boundary portion X1. Therefore, the fusion portion 50 makes it easier to prevent moisture from entering. Furthermore, the path from boundary portion X2 to boundary portion X1 is bent. As a result, even if moisture enters from boundary portion X2, it is difficult for it to reach boundary portion X1. The same applies to the second end electrode 42 side. Moreover, the capacitor 1 does not require a case.

[0056] Therefore, according to the capacitor 1 of this embodiment, moisture absorption can be reduced while maintaining light weight. Furthermore, according to the manufacturing method of the capacitor 1 of this embodiment, a lightweight capacitor 1 with excellent moisture resistance can be manufactured.

[0057] (2) Second Embodiment Next, the capacitor 1 according to the second embodiment will be described with reference to the drawings. In the second embodiment, components similar to those in the first embodiment may be given the same reference numerals as in the first embodiment, and detailed descriptions may be omitted.

[0058] Figures 4, 5A, and 5B show the capacitor 1 according to this embodiment. The capacitor 1 according to this embodiment differs from the capacitor 1 according to the first embodiment in that the capacitor element 2 further has a first additional electrode 61 and a second additional electrode 62.

[0059] (2.1) Capacitors <Capacitor element> The first additional electrode 61 is an electrode provided in addition to the first end face electrode 41. In a YZ plan view, the outer edge of the first additional electrode 61 is located outside the inner edge of the first protective portion 51 (dashed line in Figure 1). That is, the first additional electrode 61 covers the first protective portion 51 and the first end face electrode 41 that is not protected by the first protective portion 51. In particular, in this embodiment, in a YZ plan view, the outer edge of the first additional electrode 61 coincides with the outer edge of the first protective portion 51.

[0060] The first additional electrode 61 is electrically connected to the first end face electrode 41. The first additional electrode 61 is formed of a metal such as zinc by, for example, metal spraying.

[0061] On the other hand, the second additional electrode 62 is the same as the first additional electrode 61. That is, the second additional electrode 62 is an electrode provided in addition to the second end face electrode 42. In a YZ plan view, the outer edge of the second additional electrode 62 is located outside the inner edge of the second protective portion 52. That is, the second additional electrode 62 covers the second protective portion 52 and the second end face electrode 42 that is not protected by the second protective portion 52. In particular, in this embodiment, in a YZ plan view, the outer edge of the second additional electrode 62 coincides with the outer edge of the second protective portion 52.

[0062] Note that in Figures 5A and 5B, for illustrative purposes, the boundary lines between the first additional electrode 61 and the first end face electrode 41, and between the second additional electrode 62 and the second end face electrode 42 are shown, but these boundary lines may not actually be visible.

[0063] (2.2) Manufacturing method Next, the method for manufacturing the capacitor 1 according to this embodiment will be described with reference to the drawings. The method for manufacturing the capacitor 1 according to this embodiment differs from the method for manufacturing the capacitor 1 according to the first embodiment in that it further includes an additional electrode formation step.

[0064] <Additional electrode formation process> The additional electrode formation process is a step that follows the fusion bonding process shown in Figure 3C. In the additional electrode formation process, as shown in Figure 6A, the first additional electrode 61 and the second additional electrode 62 are formed by a metal spraying method.

[0065] Specifically, the first additional electrode 61 is formed by thermal spraying a metal material onto the first protective portion 51 and the first end electrode 41 not protected by the first protective portion 51. The metal material is not particularly limited, but examples include zinc.

[0066] Similarly, a second additional electrode 62 is formed by thermal spraying a metal material onto the second protective portion 52 and the second end electrode 42 that is not protected by the second protective portion 52. The metal material used to form the second additional electrode 62 may be the same as or different from the metal material used to form the first additional electrode 61.

[0067] The capacitor 1 according to this embodiment is manufactured through the above process. The following steps are optional.

[0068] <Busbar connection process> In the busbar connection process, as shown in Figure 6B, the busbars 7 are connected to the capacitor 1. Specifically, the first busbar 71 is electrically connected to the first additional electrode 61. Furthermore, the second busbar 72 is electrically connected to the second additional electrode 62. The method of connecting the busbars 7 to the capacitor 1 is not particularly limited, but examples include welding and soldering.

[0069] <Sealing process> In the sealing process, the capacitor 1 to which the busbar 7 is connected is sealed with resin. That is, the capacitor element 2 is placed in a suitable mold, and a sealing material (for example, a thermosetting resin) is injected around the entire area of ​​the capacitor element 2 to form a sealing portion 8. This produces the capacitor 1 shown in Figure 4. Note that the sealing portion 8 is shown with dashed lines in Figure 4.

[0070] (2.3) Effects This embodiment also basically provides the same effects as the first embodiment. That is, in this embodiment, as shown in Figure 5B, the boundary portion X1 between the main body 3 of the capacitor element 2 and the first end face electrode 41 is covered with a protective film 5 (particularly the third protective portion 53). This prevents moisture from entering the interior of the main body 3 of the capacitor element 2 from the boundary portion X1.

[0071] In this embodiment as well, a boundary portion X2 exists between the first end electrode 41 and the protective film 5 (particularly the first protective portion 51), but a fusion portion 50 exists in the path from boundary portion X2 to boundary portion X1. Therefore, the fusion portion 50 makes it easier to prevent moisture from entering.

[0072] In this embodiment, unlike the first embodiment, a boundary portion X3 exists between the first additional electrode 61 and the protective film 5 (particularly the first protective portion 51). However, the path from boundary portion X3 to boundary portion X1 via boundary portion X2 is more bent than in the first embodiment. As a result, even if moisture penetrates from boundary portion X3, it is even more difficult for it to reach boundary portion X1. The same applies to the second end electrode 42 side. Moreover, the capacitor 1 does not require a case.

[0073] Therefore, according to the capacitor 1 of this embodiment, moisture absorption can be reduced while maintaining light weight. Furthermore, according to the manufacturing method of the capacitor 1 of this embodiment, a lightweight capacitor 1 with excellent moisture resistance can be manufactured.

[0074] 3. Variant In the above embodiment, the capacitor element 2 is a wound-type capacitor element, but it may also be a multilayer capacitor element.

[0075] In the above embodiment, the inner surface of the first protective part 51 is bonded to the first end face electrode 41, and the inner surface of the second protective part 52 is bonded to the second end face electrode 42. However, the inner circumferential surface of the third protective part 53 may also be bonded to the outer circumferential surface 20 of the capacitor element 2. In other words, a fusion portion 50 may exist on at least a part of the inner circumferential surface of the third protective part 53.

[0076] In the above embodiment, the fused portion 50 is present on the entire inner surface of the first protective portion 51 and the entire inner surface of the second protective portion 52, respectively. However, the fused portion 50 may be present in a manner that forms a closed curve. That is, the fused portion 50 of the first protective portion 51 may be present on the inner surface of the first protective portion 51 in a manner that surrounds the inner peripheral edge of the first protective portion 51 and is enclosed by the outer peripheral edge of the first protective portion 51, forming a closed curve. Similarly, the fused portion 50 of the second protective portion 52 may be present on the inner surface of the second protective portion 52 in a manner that surrounds the inner peripheral edge of the second protective portion 52 and is enclosed by the outer peripheral edge of the second protective portion 52, forming a closed curve.

[0077] In the above embodiment, the shape and size of the first busbar 71 and the second busbar 72 are the same, but they may be different.

[0078] In the above embodiment, the protruding directions of the first busbar 71 and the second busbar 72 are opposite, but the protruding directions of the first busbar 71 and the second busbar 72 may be the same, and are not particularly limited.

[0079] In the above embodiment, the sealing portion 8 is a rectangular parallelepiped, but the sealing portion 8 may have a three-dimensional shape other than a rectangular parallelepiped.

[0080] In the second embodiment, the outer edge of the first additional electrode 61 coincides with the outer edge of the first protective portion 51, but is not particularly limited as long as it is outside the inner edge of the first protective portion 51. That is, the boundary portion X3 is located on the outer edge of the first protective portion 51, but the boundary portion X3 may be located between the outer edge and the inner edge of the first protective portion 51 on the plane of the first protective portion 51 facing the positive X-axis direction. The same applies to the second additional electrode 62.

[0081] 4. Appearance As will be apparent from the above embodiments and modifications, this disclosure includes the following aspects. In the following, reference numerals are enclosed in parentheses solely to indicate their correspondence with the embodiments.

[0082] The first embodiment is a capacitor (1) comprising a capacitor element (2) and a protective film (5). The capacitor element (2) has a first end face electrode (41), a second end face electrode (42), and an outer peripheral surface (20). The second end face electrode (42) is located on the opposite side of the first end face electrode (41). The outer peripheral surface (20) is located between the first end face electrode (41) and the second end face electrode (42). The protective film (5) has a first protective portion (51), a second protective portion (52), and a third protective portion (53). The first protective portion (51) protects the peripheral edge of the first end face electrode (41). The second protective portion (52) protects the peripheral edge of the second end face electrode (42). The third protective portion (53) is connected to the first protective portion (51) and the second protective portion (52), and protects the outer peripheral surface (20).

[0083] According to this embodiment, moisture absorption can be reduced while maintaining a lightweight design.

[0084] The second embodiment is a capacitor (1) based on the first embodiment. In the second embodiment, the protective film (5) part is the fused part (50) That is The fused portion (50) is bonded to the first end face electrode (41) and the second end face electrode (42).

[0085] According to this embodiment, moisture absorption can be further reduced.

[0086] A third embodiment is a capacitor (1) based on the first or second embodiment. In the third embodiment, the capacitor element (2) further comprises a first additional electrode (61) and a second additional electrode (62). The first additional electrode (61) is protected by the first protective portion (51) and the first end electrode (41) not protected by the first protective portion (51). part The second additional electrode (62) is covered by the second protective portion (52) and the second end electrode (42) which is not protected by the second protective portion (52). part To cover.

[0087] According to this embodiment, moisture absorption can be further reduced.

[0088] A fourth aspect is a method for manufacturing a capacitor (1), comprising a preparation step, a winding step, and a fusion step. In the preparation step, a capacitor element (2) is prepared having a first end face electrode (41), a second end face electrode (42) located on the opposite side of the first end face electrode (41), and an outer peripheral surface (20) located between the first end face electrode (41) and the second end face electrode (42). In the winding step, a protective film (5) having a width (W) longer than the distance (D) between the first end face electrode (41) and the second end face electrode (42) is wound around the outer peripheral surface (20) of the capacitor element (2), allowing it to protrude from both ends of the capacitor element (2). In the fusion process, the first overhang portion (510) of the protective film (5) that extends beyond the first end electrode (41) is bent toward the first end electrode (41) and fused to form a first protective portion (51) that protects the peripheral edge of the first end electrode (41), and the second overhang portion (520) of the protective film (5) that extends beyond the second end electrode (42) is bent toward the second end electrode (42) and fused to form a second protective portion (52) that protects the peripheral edge of the second end electrode (42).

[0089] According to this embodiment, a lightweight capacitor (1) with excellent moisture resistance can be manufactured.

[0090] A fifth aspect is a method for manufacturing a capacitor (1) according to the fourth aspect. The fifth aspect further includes an additional electrode formation step. In the additional electrode formation step, the first protective portion (51) and the first end face electrode (41) not protected by the first protective portion (51) part A first additional electrode (61) is formed by thermal spraying a metal material, and the second protective portion (52) and the second end electrode (42) not protected by the second protective portion (52) part A second additional electrode (62) is formed by thermal spraying a metal material onto it.

[0091] According to this embodiment, it is possible to manufacture a capacitor with even better moisture resistance. [Explanation of Symbols]

[0092] 1 Capacitor 2 Capacitor elements 20 Outer surface 41 1st end electrode 42 2nd end electrode 5. Protective film 51 1st Protection Department 52 2nd Protection Department 53 Third Protection Department 61 1st additional electrode 62 2nd additional electrode D distance W width

Claims

1. A capacitor element having a first end face electrode, a second end face electrode located on the opposite side of the first end face electrode, and an outer circumferential surface located between the first end face electrode and the second end face electrode, A protective film having a first protective portion that covers the peripheral edge of the first end electrode, a second protective portion that covers the peripheral edge of the second end electrode, and a third protective portion that is connected to the first and second protective portions and covers the outer circumferential surface, A first additional electrode covering at least a portion of the first protective portion and at least a portion of the first end electrode not covered by the first protective portion, The device comprises a second additional electrode that covers at least a portion of the second protective portion and at least a portion of the second end electrode not covered by the second protective portion, Capacitor.

2. A portion of the protective film is adhered to the first end electrode and the second end electrode, The capacitor according to claim 1.

3. A preparation step of preparing a capacitor element having a first end face electrode, a second end face electrode located on the opposite side of the first end face electrode, and an outer peripheral surface located between the first end face electrode and the second end face electrode, A coating step of covering the outer surface of the capacitor element with a protective film having a width longer than the distance between the first end electrode and the second end electrode, while allowing it to extend beyond both ends of the capacitor element. A bending step is to bend the first protruding portion of the protective film that extends beyond the first end electrode toward the first end electrode to form a first protective portion that covers the peripheral edge of the first end electrode, and to bend the second protruding portion of the protective film that extends beyond the second end electrode toward the second end electrode to form a second protective portion that covers the peripheral edge of the second end electrode, The process includes the steps of: spraying a metal material onto at least a portion of the first protective portion and at least a portion of the first end electrode not covered by the first protective portion; and spraying a metal material onto at least a portion of the second protective portion and at least a portion of the second end electrode not covered by the second protective portion. Capacitor manufacturing method.

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