Capacitor, and method for producing capacitor

Abstract

A capacitor (5) has a case (51) and a cover (52). The case (51) defines an inner chamber (51a) having an opening (51b). The capacitor (5) has a pair of terminal members (61, 62) extending to the outside of the case (51) via the portion of the case (51) excluding the opening (51b). The capacitor (5) has a capacitor element (53) housed in the inner chamber (51a) and electrically connected to the terminal members (61, 62). The cover (52) covers the opening (51b). The cover (52) is joined to an edge (51d) of the case (51) that defines the opening (51b), and prevents entrance of moisture into the inner chamber (51a).

Description

Capacitor and method for manufacturing the capacitor CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Patent Application No. 2024-87268 filed in Japan on May 29, 2024, and the contents of the original application are incorporated by reference in their entirety.

[0002] TECHNICAL FIELD The disclosure herein relates to capacitors and methods for manufacturing capacitors.

[0003] Patent Document 1 discloses a capacitor and a method for manufacturing the capacitor. Patent Document 1 proposes the use of a film to protect the capacitor from moisture (humidity). The contents of the prior art document are incorporated by reference as an explanation of the technical elements in this specification.

[0004] JP 2024-31095 A

[0005] As described in the prior art, capacitors are required to have excellent resistance to moisture (humidity). Furthermore, modern capacitors may be required to reduce their environmental impact. In the above-mentioned respects and in other respects not mentioned, further improvements are required in capacitors and in capacitor manufacturing methods.

[0006] One disclosed object is to provide a capacitor having excellent resistance to moisture (humidity) and a method for manufacturing the capacitor.

[0007] The capacitor disclosed herein comprises a case defining an internal chamber having an opening, at least a pair of terminal members extending to the outside of the case via a portion of the case excluding the opening, a capacitor element housed in the internal chamber and electrically connected to the terminal members, and a cover that covers the opening, is joined to the edge of the case defining the opening, and prevents moisture from entering the internal chamber.

[0008] In the disclosed capacitor, the terminal members extend to the outside of the case through a portion of the case excluding the opening. The internal chamber is closed by at least the case, the terminal members, and a cover. The opening is covered by a cover joined to the edge of the case that defines the opening. The cover prevents moisture from entering the internal chamber through the opening. This prevents moisture from entering the internal chamber in which the capacitor element is disposed. As a result, a capacitor with excellent resistance to moisture (humidity) is provided.

[0009] The method for manufacturing a capacitor disclosed herein includes a molding step of insert-molding at least a pair of terminal members into a resin case that defines an internal chamber having an opening so that they extend to the outside of the case through a portion of the case excluding the opening; an element placement step of placing a capacitor element inside the internal chamber; a connection step of electrically connecting the capacitor element and the terminal members inside the internal chamber; and a joining step of placing a cover to cover the opening and joining the cover to the edge of the case that defines the opening, thereby preventing moisture from entering the internal chamber.

[0010] According to the disclosed method for manufacturing a capacitor, the opening of the case is covered with a cover in the bonding step. The cover prevents moisture from entering the inner chamber through the opening. This prevents moisture from entering the inner chamber in which the capacitor element is disposed. As a result, a method for manufacturing a capacitor with excellent moisture resistance is provided.

[0011] The various embodiments disclosed in this specification employ different technical means to achieve their respective objectives. The reference numerals in parentheses in the claims and in this section are intended to exemplify the correspondence with the following embodiments and are not intended to limit the technical scope. The objectives, features, and advantages disclosed in this specification will become more apparent by reference to the following detailed description and the accompanying drawings.

[0012] FIG. 1 is a block diagram of a power conversion device of a first embodiment; FIG. 2 is a cross-sectional view of a capacitor of the first embodiment; FIG. 3 is a cross-sectional view of a capacitor at one stage of a manufacturing method; FIG. 4 is a cross-sectional view of a cover; FIG. 5 is a process diagram showing a manufacturing method of a capacitor; FIG. 6 is a cross-sectional view of a capacitor of a second embodiment; FIG. 7 is a cross-sectional view of a capacitor of a third embodiment; FIG. 8 is a process diagram showing a manufacturing method of a capacitor of the third embodiment; FIG. 9 is a cross-sectional view of a capacitor of a fourth embodiment.

[0013] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be designated by the same reference numerals or reference numerals that differ in the hundredth or more digits. For corresponding and / or associated parts, reference may be made to the descriptions of other embodiments.

[0014] 1 provides a drive system 1 for electric devices. The drive system 1 provides a drive system for, for example, a mobile device. The mobile device includes a vehicle for people and a non-riding device. The mobile device is a vehicle that moves on land, a ship that moves on and / or underwater, or an aircraft that moves through the air. The drive system drives a propeller of the mobile device.

[0015] The drive system 1 includes a rotating electric machine 2 that drives a propeller of the mobile device. The rotating electric machine 2 is, for example, a polyphase AC rotating electric machine. The rotating electric machine 2 rotates, for example, drive wheels that serve as the propeller. Alternatively, the rotating electric machine 2 may drive a screw or a propeller.

[0016] The drive system 1 includes a power supply device 3 (DCPS). The power supply device 3 supplies at least drive power to the rotating electric machine 2. The power supply device 3 may store power generated by the rotating electric machine 2. The power supply device 3 is, for example, a DC power supply device. The power supply device 3 is provided by, for example, a secondary battery, a fuel cell, or the like.

[0017] The drive system 1 includes a power converter 4 (INV). The power converter 4 adjusts the power supplied from the power supply device 3 and supplies the adjusted power to the rotating electric machine 2. The power converter 4 may adjust the power generated by the rotating electric machine 2 and supply the adjusted power to the power supply device 3. The power converter 4 may include, for example, an inverter circuit having an AC-to-DC conversion function. The power converter 4 may further include, for example, a converter circuit that converts the voltage of the power supply device 3.

[0018] The drive system 1 includes a capacitor 5. The capacitor 5 smoothes the DC power between the power supply device 3 and the power conversion device 4.

[0019] Case In FIG. 2, the capacitor 5 has an outer container 50. The outer container 50 has a case 51 and a cover 52. The case 51 defines an inner chamber 51a having an opening 51b. The opening 51b is the only opening of the case 51. The inner chamber 51a is a hollow rectangular parallelepiped. The case 51 is a rectangular parallelepiped that defines the inner chamber 51a inside. The case 51 has an opening 51b on one side of the rectangular parallelepiped. The case 51 has a wall with a predetermined thickness along the inner chamber 51a. When the opening 51b is positioned on the top surface, the case 51 has a bottom wall and four side walls.

[0020] The case 51 is made of an electrically insulating material. The material of the case 51 is selected to suppress moisture penetration from the outside of the outer container 50 into the inner chamber 51a to a target level or below. The thickness of the wall of the case 51 is also set to a thickness that suppresses moisture penetration to a target level or below. In this manner, the case 51 prevents moisture from penetrating into the inner chamber 51a from the outside of the outer container 50. Note that in this specification, "preventing moisture penetration" refers to suppressing moisture penetration to a target level or below.

[0021] In this embodiment, the case 51 is made of resin, such as polybutylene terephthalate (PBT resin) or polyphenylene sulfide (PPS resin).

[0022] The case 51 has a holder 51c on a part of the wall. The holder 51c supports the terminal assembly 60. The holder 51c fixes the terminal assembly 60.

[0023] The holder 51c is a part of the wall, but its length is clearly different from that of the other parts of the wall. The holder 51c has a length L51c extending along the surface of the terminal assembly 60. The length L51c is greater than the thickness of the other walls of the case 51. The material forming the case 51 is in close contact with the terminal assembly 60 along the length L51c. The material forming the case 51 is in close contact with the terminal assembly 60 without any gaps along the length L51c. As a result, the contact length between the case 51 and the terminal assembly 60 at the holder 51c is longer than the assumed contact length that would be expected if the other walls of the case 51 were in contact with the terminal assembly 60. If a small gap occurs between the case 51 and the terminal assembly 60, moisture may penetrate from the outside of the outer container 50 into the inner chamber 51a through the small gap. The length L51c prevents the formation of a small gap. The length L51c prevents moisture from penetrating from the outside of the outer container 50 into the inner chamber 51a along the terminal assembly 60.

[0024] 3 is a cross-sectional view showing the state before the case 51 and the cover 52 are joined. As shown in the figure, the edge 51d of the case 51 extends along a plane. The edge 51d is a frame-shaped joining surface having a predetermined width. The edge 51d extending along a plane ensures a secure joining between the case 51 and the cover 52. Furthermore, the edge 51d extending along a plane allows the case 51 and the cover 52 to be sandwiched between planar members, thereby facilitating manufacturing.

[0025] 2, the cover 52 is disposed so as to cover the opening 51b of the case 51. The cover 52 is fixed to the case 51. The cover 52 is joined to the edge of the case 51 that defines the opening 51b. The cover 52 is in close contact with the edge of the case 51 with no gaps.

[0026] The cover 52 has the same material as the material forming the case 51 at the portion joined to the case 51. The case 51 and the cover 52 contain the same material, ensuring a secure bond. Therefore, the layer of the cover 52 facing the case 51 is made of, for example, polybutylene terephthalate (PBT resin), polyphenylene sulfide (PPS resin), or the like. At least the surface layer of the cover 52 is made of an electrically insulating material. The surface layer of the cover 52 is preferably made of an electrically insulating material. However, the material of the cover 52 is not limited to the exemplified materials. The surface layer and / or inner layer of the cover 52 may be made of a conductive material.

[0027] In this embodiment, the cover 52 is a laminate film, which has a layer of the same material as the material forming the case 51.

[0028] The material of the cover 52 is selected so as to suppress the permeation of moisture from the outside of the outer container 50 to the inner chamber 51 a to a target level or less. The thickness of the wall of the cover 52 is also set to a thickness that suppresses the permeation of moisture to a target level or less.

[0029] As shown in FIG. 4 , the cover 52 has a resin inner layer 52a, a metal intermediate layer 52b, and a resin outer layer 52c. The resin inner layer 52a is positioned on the case 51 side when the cover 52 is joined to the case 51. The resin inner layer 52a is made of resin. The resin inner layer 52a is made of, for example, polybutylene terephthalate (PBT resin), polyphenylene sulfide (PPS resin), or the like. The metal intermediate layer 52b is made of metal foil. The metal intermediate layer 52b is made of, for example, aluminum foil. The resin outer layer 52c provides the outer surface of the outer container 50. The resin outer layer 52c is made of resin. The resin outer layer 52c is made of, for example, polyamide.

[0030] The material and thickness of the cover 52 are selected so as to suppress the permeation of moisture from the outside of the outer container 50 into the inner chamber 51 a to a target level or less. The cover 52 and the case 51 are joined so as to suppress the permeation of moisture from the outside of the outer container 50 into the inner chamber 51 a to a target level or less. In this way, the cover 52 prevents moisture from entering the inner chamber 51 a from the outside of the outer container 50.

[0031] Capacitor Element The capacitor 5 has at least one capacitor element 53. The capacitor element 53 is housed in the internal chamber 51a. The capacitor element 53 is positioned in the internal chamber 51a via the opening 51b. In this embodiment, a plurality of capacitor elements 53 are housed in the internal chamber 51a. The plurality of capacitor elements 53 are electrically connected to provide the drive system 1 with the required capacitance.

[0032] 2, the capacitor 5 has a sealing material 54. The sealing material 54 is disposed in the gap between the case 51 and the capacitor element 53. The sealing material 54 is in a hardened state in the completed capacitor 5. The sealing material 54 is filled into the gap between the case 51 and the capacitor element 53 in a fluid state before hardening, and is then hardened. The filling is carried out by pouring the sealing material 54 in a fluid state into the internal chamber 51a. The sealing material 54 is filled so as to enclose the capacitor element 53 and all of the multiple internal connection ends 64 described below.

[0033] The sealing material 54 is a resin material that hardens at room temperature. For example, the sealing material 54 is a room-temperature-hardening type silicone rubber. The sealing material 54 hardens to a degree that secures the capacitor element 53 in the inner chamber 51a. The sealing material 54 enables the capacitor element 53 to be secured inside the case 51 without requiring a heating process. Therefore, the energy required for the heating process can be reduced. Reducing the energy required to manufacture the capacitor 5 also reduces the burden on the environment.

[0034] An air chamber 55 may be formed due to air bubbles mixed in the sealing material 54 and / or unavoidable gaps between the cover 52 and the sealing material 54. The air chamber 55 occupies a very small volume within the inner chamber 51a.

[0035] Terminal Assembly The capacitor 5 has a terminal assembly 60. The terminal assembly 60, together with the case 51, contributes to sealing the internal chamber 51a. The terminal assembly 60 extends to the outside of the case 51 through the area of ​​the case 51 excluding the opening 51b. The terminal assembly 60 extends to the outside of the case 51 through the holder 51c without passing through the opening 51b. The terminal assembly 60 has an inner end and an outer end. The inner end of the terminal assembly 60 protrudes into the internal chamber 51a. The outer end of the terminal assembly 60 protrudes outside the outer container 50.

[0036] The terminal assembly 60 provides electrical conductivity between the outside of the outer container 50 and the inside of the inner chamber 51a. The terminal assembly 60 includes at least a pair of terminal members 61, 62. The pair of terminal members 61, 62 has an inner end and an outer end. The inner ends of the pair of terminal members 61, 62 protrude into the inner chamber 51a. The outer ends of the pair of terminal members 61, 62 protrude outside the outer container 50. The pair of terminal members 61, 62 electrically connect the inside of the inner chamber 51a and the outside of the outer container 50. The pair of terminal members 61, 62 are arranged between the inside of the inner chamber 51a and the outside of the outer container 50. The pair of terminal members 61, 62 are arranged to penetrate the case 51. The pair of terminal members 61, 62 are connected to the case 51 to provide an airtight state.

[0037] One of the pair of terminal members 61, 62 provides a positive terminal of the capacitor 5. The other of the pair of terminal members 61, 62 provides a negative terminal of the capacitor 5. Each of the terminal members 61, 62 is a conductive member. Each of the terminal members 61, 62 may be provided by a conductive metal plate. In this case, each of the terminal members 61, 62 is also called a bus bar. The terminal members 61 and 62 extend to the outside of the case 51 through a portion of the case 51 excluding the opening 51 b.

[0038] When the capacitor 5 includes a plurality of capacitor elements 53, the terminal assembly 60 electrically connects the plurality of capacitor elements 53. The terminal assembly 60 may include an additional terminal member in addition to the pair of terminal members 61, 62. The additional terminal member provides a terminal for testing or the like.

[0039] Terminal members 61 and 62 extend to the outside of case 51 via holder 51c without passing through opening 51b. At least a portion of terminal member 61 and at least a portion of terminal member 62 are in direct contact with the material forming case 51. Terminal members 61 and 62 extend from holder 51c to electrically connect the inside and outside of outer container 50 while being in close contact with the material forming case 51.

[0040] The terminal assembly 60 has an insulating member 63. The insulating member 63 is disposed between the pair of terminal members 61, 62. The insulating member 63 is disposed on the portions of the pair of terminal members 61, 62 that are disposed in parallel. The parallel arrangement of the pair of terminal members 61, 62 contributes to suppressing inductance components in the drive system 1. The insulating member 63 extends to the outside of the case 51 through a portion of the case 51 excluding the opening 51b. The insulating member 63 extends to the outside of the case 51 together with the pair of terminal members 61, 62. The insulating member 63 extends to the outside of the case 51 through the holder 51c without passing through the opening 51b. The insulating member 63 also extends into the inner chamber 51a.

[0041] The insulating member 63 is provided by, for example, insulating paper made of resin, and is in close contact with both the terminal member 61 and the terminal member 62.

[0042] The capacitor element 53 and the terminal assembly 60 have a plurality of internal connection ends 64 in the inner chamber 51a. The plurality of internal connection ends 64 include an electrical connection end between the terminal member 61 and one electrode of the capacitor element 53. The plurality of internal connection ends 64 include an electrical connection end between the terminal member 62 and the other electrode of the capacitor element 53. One of the plurality of internal connection ends 64 is shown in the drawing. The other internal connection end 64 is located on the front or back side of the page. That is, the capacitor element 53 is electrically connected to the terminal assembly 60 in the inner chamber 51a. The capacitor element 53 is electrically connected to both the terminal member 61 and the terminal member 62 in the inner chamber 51a.

[0043] 5 is a process diagram showing a capacitor manufacturing method 180. The capacitor manufacturing method 180 includes a molding step 181. In the molding step 181, a resin case 51 is molded, which defines an inner chamber 51a having an opening 51b. In the molding step 181, at least a pair of terminal members 61, 62 are insert-molded into the case 51. In the molding step 181, the pair of terminal members 61, 62 are arranged so as to extend to the outside of the case 51 via a portion of the case 51 excluding the opening 51b. In the molding step 181, an insulating member 63 is arranged between the pair of terminal members 61, 62, and the insert molding process is performed.

[0044] In molding step 181, resin molding is performed so that the material forming case 51 comes into direct contact with both a portion of the surface of terminal member 61 and a portion of the surface of terminal member 62. Note that the direct contact may involve the presence of a primer that improves adhesion between terminal members 61, 62 and the resin material.

[0045] The capacitor manufacturing method 180 includes an element placement step 182. In the element placement step 182, the capacitor element 53 is placed into the inner chamber 51a through the opening 51b of the case 51. In the element placement step 182, the capacitor element 53 is positioned at a predetermined position in the inner chamber 51a. In the element placement step 182, the capacitor element 53 is placed inside the inner chamber 51a.

[0046] The capacitor manufacturing method 180 includes a connecting step 183. In the connecting step 183, the capacitor element 53 and the terminal members 61, 62 are electrically connected inside the inner chamber 51a. In the connecting step 183, a plurality of internal connection ends 64 are formed. The connecting step 183 includes a first connecting step for the terminal member 61. The first connecting step is also a connecting step for one electrode of the capacitor element 53. The connecting step 183 includes a second connecting step for the terminal member 62. The second connecting step is also a connecting step for the other electrode of the capacitor element 53.

[0047] The capacitor manufacturing method 180 includes a filling step 184. In the filling step 184, the encapsulant 54 is filled into the gap between the case 51 and the capacitor element 53 through the opening 51b. The encapsulant 54 is filled up to near the edge 51d of the opening 51b. The encapsulant 54 is filled so as to completely encase the capacitor element 53. The encapsulant 54 is filled so as to encase the multiple internal connection ends 64. The encapsulant 54 is filled so as to encase the protruding portions of the terminal assembly 60 that protrude into the internal chamber 51a. Portions of the terminal members 61, 62 are positioned protruding into the internal chamber 51a. The encapsulant 54 is filled so as to encase the protruding portions of the terminal members 61, 62. As a result, after the filling step 184, the capacitor element 53, the multiple internal connection ends 64, and the pair of terminal members 61, 62 are completely covered with the encapsulant 54. After the filling step 184, only the liquid surface of the sealing material 54 is exposed in the inner chamber 51a.

[0048] The capacitor manufacturing method 180 includes a curing step 185. In the curing step 185, the encapsulant 54 is cured from a flowable state. The encapsulant 54 is a room-temperature curing resin material. Therefore, the curing step 185 proceeds gradually after the preceding filling step 184. The curing step 185 hardens the encapsulant 54 to a level at which subsequent steps can be performed. The encapsulant 54 only needs to reach its final hardness in the manufacturing process, including the subsequent steps. Note that the encapsulant 54 is not limited to a room-temperature curing resin material, but may also be a thermosetting resin material. When the encapsulant 54 is a thermosetting resin material, the curing step 185 may be performed after the filling step 184. In this case, the curing step 185 is not limited to being performed immediately after the filling step 184. The curing step 185 may also be performed after the subsequent step.

[0049] The capacitor manufacturing method 180 includes a cover placement step 186. In the cover placement step 186, the cover 52 is placed so as to cover the opening 51b of the case 51. The cover 52 is placed so as to completely cover the opening 51b of the case 51.

[0050] The capacitor manufacturing method 180 includes a joining step 187. In the joining step 187, the cover 52 is joined to the edge 51d of the case 51, which defines the opening 51b. The joining step 187 is performed by pressing the cover 52 against the edge 51d, which extends along a plane. The joining is performed by melting and fusing the resin material of the case 51 and the resin material of the cover 52. The joining of the case 51 and the cover 52 prevents moisture from entering the inner chamber 51a.

[0051] In this embodiment, a series of steps from the element placement step 182 to the bonding step 187 are performed under atmospheric pressure. Therefore, there is no pressure difference between the inside and outside of the outer container 50 throughout the series of steps. After the manufacturing method for the capacitor 5 is completed, a pressure difference may occur between the inside and outside of the outer container 50 due to pressure changes caused by temperature differences, etc. The outer container 50 including the case 51 and the cover 52, the terminal assembly 60, and their joints maintain the internal chamber 51 a in a sealed state within the expected operating environment range for the capacitor 5. In other words, the outer container 50 including the case 51 and the cover 52, the terminal assembly 60, and their joints provide a pressure-resistant container that can withstand the pressure difference between the inside and outside of the outer container 50 within the expected operating environment range for the capacitor 5.

[0052] In this embodiment, the terminal members 61 and 62 extend to the outside of the case 51 through portions of the case 51 excluding the opening 51b. In this embodiment, all of the terminal members 61 and 62 are disposed between the interior and exterior of the case 51, penetrating the wall of the case 51. The inner chamber 51a is sealed by at least the case 51, the terminal members 61 and 62, and the cover 52. In this embodiment, the inner chamber 51a is sealed by the case 51, the terminal members 61 and 62, the insulating member 63, and the cover 52. The opening 51b is covered by the cover 52. The cover 52 is joined to an edge 51d of the case 51 that defines the opening 51b. The cover 52 prevents moisture from entering the inner chamber 51a through the opening 51b. This prevents moisture from entering the inner chamber 51a in which the capacitor element 53 is disposed. In the inner chamber 51a, the sealing material 54 contributes to preventing moisture from reaching the capacitor element 53. As a result, the capacitor 5 is provided with excellent resistance to moisture (humidity).

[0053] According to this embodiment, in the joining step 187, the opening 51b of the case 51 is covered with the cover 52. The cover 52 prevents moisture from entering the inner chamber 51a via the opening 51b. This prevents moisture from entering the inner chamber 51a in which the capacitor element 53 is disposed. As a result, a method for manufacturing a capacitor 5 having excellent resistance to moisture (humidity) is provided.

[0054] Second Embodiment This embodiment is a modification of the preceding embodiment. In the preceding embodiment, the insulating member 63 disposed between the pair of terminal members 61, 62 extends to the outside of the case 51. Instead, in this embodiment, the insulating member 63 remains within the case 51.

[0055] 6, the terminal assembly 60 has a pair of terminal members 61, 62 and an insulating member 263. The insulating member 263 is disposed between the pair of terminal members 61, 62. The insulating member 263 does not protrude outward from the holder 51c. The edge portion of the insulating member 263 remains within the wall of the case 51 including the holder 51c. The edge of the insulating member 263 is embedded in the material forming the case 51 in the holder 51c.

[0056] A wall of the material forming the case 51 exists between the edge of the insulating member 263 and the outside of the case 51. Therefore, at least a portion of the insulating member 263 is in direct contact with the material forming the case 51. The direct contact enables the case 51, the terminal members 61 and 62, and the insulating member 263 to be securely fixed together. Furthermore, the direct contact prevents moisture from penetrating along the insulating member 263. In this way, the direct contact between the material forming the case 51 and the material of the insulating member 263 prevents moisture from penetrating into the inner chamber 51a from the outside of the outer container 50.

[0057] The pair of terminal members 61, 62 are in direct contact only with the material forming the case 51 on the outer side of the case 51 relative to the edge of the insulating member 263. In this region, the surface of the terminal member 61 is in direct contact only with the material forming the case 51 around its entire periphery. The surface of the terminal member 62 is also in direct contact only with the material forming the case 51 around its entire periphery. The surfaces of both of the illustrated terminal members 61, 62 are in direct contact only with the material forming the case 51 around their entire periphery. In other words, the surfaces of all of the terminal members 61, 62 of the capacitor 5 are in direct contact only with the material forming the case 51 around their entire periphery.

[0058] The inner chamber 51a is isolated from the outside by the case 51, the terminal members 61 and 62, and the cover 52. In this structure, the insulating member 263 is not exposed to the outside of the case 51. This prevents moisture from penetrating the insulating member 263. This embodiment more reliably prevents moisture from entering the inner chamber 51a in which the capacitor element 53 is disposed. As a result, a capacitor 5 having excellent resistance to moisture (humidity) is provided.

[0059] Third Embodiment This embodiment is a modification based on the preceding embodiment. In the preceding embodiment, the manufacturing method of the capacitor 5 is performed under atmospheric pressure. Instead, in this embodiment, at least the bonding step 187 is performed in a low-pressure environment below atmospheric pressure. The low-pressure environment is, for example, a vacuum environment.

[0060] 7 is a cross-sectional view of the capacitor 5 of this embodiment. The capacitor 5 has a cover 352. The cover 352 has a concave surface 356 on its outer surface. The cover 352 is curved in a concave shape from the outside of the case 51 toward the inner chamber 51a. The cover 352 is at least partially in close contact with the surface of the sealant 54. An air chamber 355 may be partially formed between the cover 352 and the sealant 54.

[0061] The capacitor 5 is designed to be used in an atmospheric environment, in which the inner chamber 51a is at a negative pressure relative to the outside of the outer container 50.

[0062] 8 is a process diagram showing a capacitor manufacturing method 380. The capacitor manufacturing method 380 includes a molding step 181, an element placement step 182, a connection step 183, a filling step 184, a curing step 185, a cover placement step 186, and a bonding step 187.

[0063] Furthermore, the capacitor manufacturing method 380 includes a depressurization step 381. The depressurization step 381 is performed at least before the bonding step 187. The depressurization step 381 is performed before the cover placement step 186. The depressurization step 381 may be performed before the curing step 185. The depressurization step 381 may be performed before the filling step 184. The depressurization step 381 may be performed before the connecting step 183. The depressurization step 381 may be performed before the element placement step 182.

[0064] In the decompression step 381, the components are placed in a low-pressure environment. This reduces the pressure in the internal chamber 51a. The pressure inside the internal chamber 51a is reduced to a pressure lower than atmospheric pressure. The pressure lower than atmospheric pressure is achieved in a decompression tank, and an intermediate product in the process of manufacturing is placed in the decompression tank. In this embodiment, the decompression tank is provided by a vacuum tank. In this embodiment, the decompression step 381 is performed by placing the intermediate product (component) in the vacuum tank. The case 51 containing the capacitor element 53, the cover 352, and at least the tools required for the joining step 187 are placed in a low-pressure environment. At this stage, the cover 352 has not yet attained the shape shown in FIG. 7. At this stage, the cover 352 is in the flat shape shown in FIG. 2. In the low-pressure environment, the cover placement step 186 and the joining step 187 are performed. The joining step 187 is performed in a negative pressure environment lower than atmospheric pressure. As a result, a low-pressure environment is sealed inside the internal chamber 51a.

[0065] The capacitor manufacturing method 380 includes a pressurizing step 382. In the pressurizing step 382, ​​atmospheric pressure is applied from the outside of the cover 352. Specifically, the capacitor 5 is taken out of the vacuum chamber into the atmospheric environment, whereby atmospheric pressure is applied from the outside of the cover 352.

[0066] The capacitor manufacturing method 380 includes a deformation step 383. In the deformation step 383, the shape of the cover 352 is deformed into the product shape due to a pressure difference. In the deformation step 383, the pressure difference changes the shape of the cover. The cover 352 has the flat shape shown in FIG. 2 immediately after the bonding step 187. The pressure difference causes the cover 352 to deform so as to contact the sealant 54. Note that at least one air chamber 355 may be formed between the cover 352 and the sealant 54. The cover 352 deforms into the product shape having a concave surface 356 shown in FIG. 7. Therefore, the capacitor manufacturing method 380 includes a deformation step 383 after the bonding step 187, in which atmospheric pressure is applied to the outside of the cover 352 to deform the cover 352 toward the inner chamber 51a.

[0067] After the cover 352 is deformed, the cover 352 attempts to restore its shape from the curved concave surface 356 to a flat plate shape due to its own elasticity. The cover 352 maintains the concave surface 356 while the pressure difference is maintained. When the pressure difference is lost, the cover 352 returns to its original shape and the concave surface 356 is also lost. Therefore, the loss of the pressure difference can be indicated by the product shape.

[0068] The capacitor manufacturing method 380 includes a maintaining step 384. During the maintaining step 384, a pressure differential is maintained across the cover 352. At the same time, during the maintaining step 384, the product shape of the cover 352, characterized by the concave surface 356, is maintained.

[0069] Fourth Embodiment This embodiment is a modification based on the preceding embodiment. In the preceding embodiment, the cover 52 is a laminate sheet. Instead, in this embodiment, the cover 452 is provided by a resin cap.

[0070] 9, the cover 452 is a plate-shaped member made of resin. The material forming the cover 452 is the same as the material forming the case 51. The thickness of the cover 452 is equal to the average thickness of the case 51. This allows the cover 452 to have the same low moisture permeability as the case 51.

[0071] The cover 452 is disposed so as to cover the opening 51b. The cover 452 is joined to the edge of the case 51 that defines the opening 51b. The joining is achieved by integrating the cover 452 and the case 51 by welding. The joining reduces the permeation of moisture through the joining surface to a level similar to that of the cover 452 or the case 51. The joining may also be achieved by using an adhesive.

[0072] Other Embodiments The disclosure in this specification and drawings, etc. is not limited to the exemplified embodiments. The disclosure encompasses the exemplified embodiments and variations thereon by those skilled in the art. For example, the disclosure is not limited to the combinations of parts and / or elements shown in the embodiments. The disclosure can be implemented in various combinations. The disclosure can have additional parts that can be added to the embodiments. The disclosure encompasses the omission of parts and / or elements from the embodiments. The disclosure encompasses the substitution or combination of parts and / or elements between one embodiment and another embodiment. The disclosed technical scope is not limited to the description of the embodiments. Some disclosed technical scopes are defined by the claims, and should be interpreted as including all modifications within the meaning and scope equivalent to the claims.

[0073] The disclosure in the specification, drawings, etc. is not limited by the claims. The disclosure in the specification, drawings, etc. encompasses the technical ideas described in the claims, and extends to more diverse and broader technical ideas than the technical ideas described in the claims. Therefore, various technical ideas can be extracted from the disclosure in the specification, drawings, etc. without being bound by the claims.

[0074] In the above embodiment, the case 51 is made of an electrically insulating resin. Alternatively, the case may be made of a conductive material. For example, aluminum or the like can be used as the conductive material. In this case, the case made of a conductive material is provided with a hermetic seal for arranging terminal members. The hermetic seal allows for the arrangement of terminal members that penetrate the case. Moreover, the hermetic seal can achieve high moisture resistance. In this case, the inner chamber 51a is also sealed by the case, cover, terminal members, and insulating member.

[0075] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0076] (Technical Idea 1) A capacitor comprising: a case (51) defining an inner chamber (51a) having an opening (51b); at least a pair of terminal members (61, 62) extending to the outside of the case via a portion of the case excluding the opening; a capacitor element (53) housed in the inner chamber and electrically connected to the terminal members; and a cover (52) covering the opening, joined to the edge of the case defining the opening, and preventing moisture from entering the inner chamber.

[0077] (Technical Concept 2) The capacitor according to Technical Concept 1, wherein the edge of the case extends along a plane.

[0078] (Technical Concept 3) The capacitor according to Technical Concept 1 or 2, wherein the cover has the same material as the material forming the case at the portion joined to the case.

[0079] (Technical Concept 4) The capacitor according to Technical Concept 3, wherein the cover is a laminate film having a layer of the same material as the material forming the case.

[0080] (Technical Concept 5) The capacitor according to any one of Technical Concepts 1 to 4, further comprising a sealing material (54) disposed between the case and the capacitor element.

[0081] (Technical Idea 6) The capacitor according to any one of Technical Ideas 1 to 5, wherein the internal chamber is under negative pressure in an atmospheric environment.

[0082] (Technical Idea 7) The capacitor according to any one of Technical Ideas 1 to 6, wherein the cover is curved concavely from the outside of the case toward the inner chamber.

[0083] (Technical Idea 8) The capacitor according to any one of Technical Ideas 1 to 7, further comprising an insulating member (63) disposed between the pair of terminal members and extending to the outside of the case together with the pair of terminal members via a portion of the case excluding the opening.

[0084] (Technical Concept 9) The capacitor according to Technical Concept 8, wherein at least a portion of the insulating member is in direct contact with the material forming the case.

[0085] (Technical Idea 10) A capacitor according to any one of Technical Ideas 1 to 9, wherein at least a portion of the pair of terminal members is in direct contact with the material forming the case.

[0086] (Technical Idea 11) A method for manufacturing a capacitor, comprising: a molding step (181) of insert-molding at least a pair of terminal members (61, 62) into a resin case (51) that defines an internal chamber (51a) having an opening (51b) so that the terminal members extend to the outside of the case through a portion of the case excluding the opening; an element placement step (182) of placing a capacitor element (53) inside the internal chamber; a connection step (183) of electrically connecting the capacitor element and the terminal members inside the internal chamber; and a joining step (187) of placing a cover to cover the opening and joining the cover to the edge of the case that defines the opening, thereby preventing moisture from entering the internal chamber.

[0087] (Technical Concept 12) The method for manufacturing a capacitor according to Technical Concept 11, wherein the molding step (181) is performed by disposing an insulating member (63) between the pair of terminal members.

[0088] (Technical Concept 13) The method for manufacturing a capacitor according to Technical Concept 11 or 12, wherein the bonding step (187) is performed in a negative pressure environment lower than atmospheric pressure.

[0089] (Technical Idea 14) The method for manufacturing a capacitor according to Technical Idea 12 or Technical Idea 13 further includes, after the joining step, a deformation step (383) of applying atmospheric pressure to the outside of the cover to deform the cover toward the inner chamber.

Claims

1. A capacitor comprising: a case (51) defining an internal chamber (51a) having an opening (51b); at least a pair of terminal members (61, 62) extending to the outside of the case via a portion of the case excluding the opening; a capacitor element (53) housed in the internal chamber and electrically connected to the terminal members; and a cover (52) covering the opening, joined to the edge of the case defining the opening, and preventing moisture from entering the internal chamber.

2. The capacitor of claim 1, wherein the edge of the case extends along a plane.

3. The capacitor according to claim 1, wherein the cover has the same material as the material forming the case at the portion where it is joined to the case.

4. The capacitor according to claim 3, wherein the cover is a laminate film having a layer of the same material as the material forming the case.

5. The capacitor of claim 1, further comprising a sealant (54) disposed between said case and said capacitor element.

6. The capacitor according to claim 1, wherein the internal chamber is at a negative pressure in an atmospheric environment.

7. The capacitor according to claim 1, wherein the cover is curved concavely from the outside of the case toward the interior chamber.

8. A capacitor as described in claim 1, further comprising an insulating member (63) disposed between the pair of terminal members and extending to the outside of the case together with the pair of terminal members through a portion of the case excluding the opening.

9. The capacitor of claim 8, wherein at least a portion of said insulating member is in direct contact with the material forming said case.

10. A capacitor according to any one of claims 1 to 9, wherein at least a portion of the pair of terminal members is in direct contact with the material forming the case.

11. A method for manufacturing a capacitor, comprising: a molding step (181) of insert-molding at least a pair of terminal members (61, 62) into a resin case (51) defining an internal chamber (51a) having an opening (51b) so that the terminal members extend to the outside of the case through a portion of the case excluding the opening; an element placement step (182) of placing a capacitor element (53) inside the internal chamber; a connection step (183) of electrically connecting the capacitor element and the terminal members inside the internal chamber; and a joining step (187) of placing a cover to cover the opening and joining the cover to the edge of the case defining the opening, thereby preventing moisture from entering the internal chamber.

12. The method for manufacturing a capacitor according to claim 11, wherein the molding step (181) is performed by placing an insulating member (63) between the pair of terminal members.

13. The method of manufacturing a capacitor according to claim 11, wherein the bonding step (187) is carried out in a negative pressure environment below atmospheric pressure.

14. The method for manufacturing a capacitor according to claim 12, further comprising, after the joining step, a deformation step (383) of applying atmospheric pressure to the outside of the cover to deform the cover toward the inner chamber.

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