Capacitor and method for manufacturing the same

Abstract

To provide a capacitor with an excellent resistance to heat.SOLUTION: There is provided a capacitor including: a thin-film polymer laminate capacitor element; an exterior case storing the thin-film polymer laminate capacitor element; one of a cured rubber and a curable resin fixing the thin-film polymer laminate capacitor element to the exterior case; and an exterior lid. The thin-film polymer laminate capacitor element is sealed in an inner space formed by the exterior case and the exterior lid joined to each other. The one of the cured rubber and the curable resin covers the lower end part of the thin-film polymer laminate capacitor element.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a capacitor having excellent heat resistance and a method for manufacturing the same.

Background Art

[0002] Conventionally, it has been known to fix and seal a capacitor element with resin in an internal space formed by an exterior case and an exterior lid.

[0003] Patent Document 1 describes a capacitor element in which a lower electrode lead-out portion in an exterior case is covered and fixed with resin. This capacitor element is sealed by an exterior case and an exterior case lid, and the exterior case and the exterior case lid use a plastic material. Further, as an embodiment, a capacitor element using polypropylene or the like is described.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent years, for applications such as in-vehicle use, improvement of the heat resistance of electronic devices has been demanded. In-vehicle semiconductors can operate up to an ambient temperature of 250°C by using SiC, but the operating guarantee temperature of peripheral components such as capacitors has not yet reached that level.

[0006] Against this background, an object of the present disclosure is to provide a capacitor having excellent heat resistance.

Means for Solving the Problems

[0007] The problems of the present disclosure can be solved by the following aspects of the invention according to the present disclosure: <Aspect 1> Thin film polymer multilayer capacitor elements, an outer case for housing the thin film polymer multilayer capacitor element; a cured rubber or curable resin that fixes the thin film polymer multilayer capacitor element to the exterior case; and Exterior lid Equipped with the thin film polymer multilayer capacitor element is sealed in an internal space formed by the outer case and the outer lid joined together, the cured rubber or the curable resin covers the lower end of the thin film polymer multilayer capacitor element; Capacitor. <Aspect 2> 2. The capacitor of claim 1, wherein the outer case and the outer lid are made of metal. <Aspect 3> The capacitor according to any one of aspects 1 and 2, wherein the joining between the exterior lid and the exterior case is double seamed. <Aspect 4> Aspect 4. The capacitor according to any one of aspects 1 to 3, wherein the internal space is a vacuum or is filled with an inert gas. <Aspect 5> 5. The capacitor of claim 4, wherein the inert gas is nitrogen gas, helium gas, or a mixture thereof. <Aspect 6> 6. The capacitor according to any one of aspects 1 to 5, wherein the rubber or the curable resin does not emit a reaction gas when cured. <Aspect 7> 7. The capacitor according to any one of aspects 1 to 6, wherein the rubber or the curable resin includes at least one selected from the group consisting of RTV silicone rubber, epoxy resin, urethane resin, and diallyl phthalate resin. <Aspect 8> The height H of the hardened rubber or hardened resin in the internal space R is the height H of the internal space I The capacitor according to any one of aspects 1 to 7, wherein the capacitance is 10 to 50% of the capacitance. <Aspect 9> The capacitor according to any one of Aspects 1 to 8, wherein the rubber or the curable resin adheres to at least a part of the inner side wall of the exterior case and the inner wall of the exterior lid. <Aspect 10> Having a connection member for electrically connecting the thin film polymer laminated capacitor element to the outside, The connection member extends through the exterior lid, One end portion of the connection member is connected to the thin film polymer laminated capacitor element in the internal space, The other end portion of the connection member is disposed outside the capacitor. The capacitor according to any one of Aspects 1 to 9. <Aspect 11> The capacitor according to Aspect 10, wherein a portion of the connection member passing through the exterior lid and adjacent to the inner wall of the exterior lid is covered with the rubber or the curable resin. <Aspect 12> The capacitor according to Aspect 10 or Aspect 11, wherein the connection member is composed of an integral member. <Aspect 13> The connection member is composed of a plurality of members connected to each other. Among these plurality of members, at least the member connected to the thin film polymer laminated capacitor element in the internal space is composed of an integral member. The capacitor according to Aspect 10 or Aspect 11. <Aspect 14> The capacitor according to any one of Aspects 10 to 13, wherein the connection member is made of a highly rigid material. <Aspect 15> The capacitor according to any one of Aspects 1 to 14, which can be continuously used at 125 °C. <Aspect 16> The capacitor according to any one of Aspects 1 to 15, which is a capacitor for use at a voltage of 200 V or higher. <Aspect 17> A method for manufacturing a capacitor, Providing a thin film polymer laminated capacitor element, Providing an exterior case that contains uncured rubber or curable resin and has an opening, Storing the thin-film polymer laminated capacitor element in the exterior case and covering a lower end portion of the thin-film polymer laminated capacitor element with the uncured rubber or the curable resin, Arranging and joining an exterior lid so as to cover the opening of the exterior case to seal the exterior case, and After sealing the exterior case, curing the uncured rubber or the curable resin, Including Method. <Aspect 18> The method for manufacturing a capacitor according to Aspect 17, wherein the exterior case and the exterior lid are made of metal, and the exterior lid and the exterior case are joined to each other by double winding. <Aspect 19> The method for manufacturing a capacitor according to Aspect 17 or Aspect 18, wherein the exterior case is sealed under vacuum or filled with an inert gas and then sealed. <Aspect 20> When providing the thin-film polymer laminated capacitor element, providing the thin-film polymer laminated capacitor element pre-fixed to the exterior lid, Here, the thin-film polymer laminated capacitor element is fixed to the exterior lid by a connection member for electrically connecting the thin-film polymer laminated capacitor element to the outside, and The connection member extends through the exterior lid. The method according to any one of Aspects 17 to 19. <Aspect 21> After sealing the thin-film polymer laminated capacitor element and before curing the uncured rubber or the curable resin, by rotating or inverting the exterior case, the uncured rubber or the curable resin is adhered to the inner side wall of the exterior case and the inner wall of the exterior lid, and a portion of the connection member passing through the exterior lid and adjacent to the inner wall of the exterior lid is covered with the rubber or the curable resin. The method according to Aspect 20.

Advantages of the Invention

[0008] According to the invention related to the present disclosure, a capacitor having excellent heat resistance can be provided.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0010] <<Capacitor>> The invention related to the present disclosure is a capacitor, which a thin film polymer laminated capacitor element, an exterior case for housing the thin film polymer laminated capacitor element, a cured rubber or curable resin that fixes the thin film polymer laminated capacitor element to the exterior case, and an exterior lid and includes the thin film polymer laminated capacitor element is sealed in an internal space formed by the exterior case and the exterior lid joined to each other, the cured rubber or curable resin covers the lower end portion of the thin film polymer laminated capacitor element.

[0011] Conventionally, it is known to fix and seal a capacitor element with resin in an internal space formed by an exterior case and an exterior lid.

[0012] Conventionally, it has been known to cover and fix only the area below the capacitor element with a curable resin in the internal space of the exterior case, which can reduce the product weight.

[0013] On the other hand, conventional capacitors have adopted those using polypropylene or the like as the capacitor element. The operating guarantee temperature of a conventional power film capacitor using polypropylene is at most 125°C, which shows a large deviation from in-vehicle semiconductors that can operate up to an ambient temperature of 250°C by using SiC.

[0014] In contrast, the capacitor according to the present invention uses a thin-film polymer laminated capacitor element with a thermosetting resin as the dielectric, so it is suitable for applications that require high heat resistance, such as in-vehicle applications and power electronics capacitor applications. The thin-film polymer laminated capacitor element has a structure in which dielectric layers (resin thin-film layers) containing a thermosetting resin and electrode layers (metal thin-film layers) containing a metal are alternately laminated. That is, since the thin-film polymer laminated capacitor is superior in heat resistance to conventional film capacitors using a thermoplastic resin as the dielectric, the present invention has the advantages that a resin with a high curing temperature can be used for the resin that fixes the element inside the exterior case, and a high operating guarantee temperature can be obtained.

[0015] In the capacitor of the present invention, by using a thin-film polymer laminated capacitor element as the internal element of the capacitor and making the exterior airtight, the environmental resistance can be greatly improved, and for example, a power film capacitor that can be continuously used and guaranteed at 150 to 200°C can be provided. Furthermore, according to the present invention, miniaturization and high reliability of the power film capacitor can be achieved.

[0016] The capacitor of the present invention will be described with reference to the drawings. The drawings are illustrative and do not limit the present invention. The drawings are not to scale.

[0017] Figure 1 (Fig. 1) shows an example of a capacitor according to the present invention. The capacitor 10 according to the present invention includes a thin-film polymer laminated capacitor element 101, a cured rubber or curable resin 106, an exterior case 105 for housing the thin-film polymer laminated capacitor element 101, and an exterior lid 102. The exterior case 105 has an opening for inserting the capacitor element and the like into the exterior case 105 during the manufacture of the capacitor. This opening is covered and closed by the exterior lid 102.

[0018] The exterior lid 102 is connected to the thin-film polymer laminated capacitor element 101 via two connection members 103a and 103b. These connection members are members for electrically connecting the thin-film polymer laminated capacitor element to the outside. The connection member may be composed of a plurality of members. For example, it may be composed of a first member (so-called terminal portion) passing through the exterior lid and a second member (so-called lead) connecting the inner space side end portion of the first member and the capacitor element. In this case, at least the second member may be formed from an integral member. Alternatively, the connection member may be formed from a single integrally molded member. The thin-film polymer laminated capacitor element 101 has electrode lead-out portions 104a and 104b, which face the inner side wall of the exterior case 105.

[0019] The thin-film polymer laminated capacitor element 101 is sealed in the internal space formed by the joining of the exterior case 105 and the exterior lid 102. The lower end portion of the thin-film polymer laminated capacitor element 101 adjacent to the bottom of the exterior case is covered by the cured rubber or curable resin 106, whereby the thin-film polymer laminated capacitor element is fixed to the exterior case. The height H of the cured rubber or curable resin 206 R is 10 to 50% of the height H of the cavity of the exterior case (or the height of the internal space formed later by the exterior case and the exterior lid), and may be 20 to 40%. I

[0020] In FIG. 1, both the exterior case 105 and the exterior lid 102 are made of metal, and their joining is by double winding. The cured rubber or curable resin 106 fills only a part of the internal space of the capacitor. In the aspect of FIG. 1, the height H of the internal space of the capacitor I covers approximately 1 / 4 of it. The internal space of the capacitor in FIG. 1 is either a vacuum or filled with an inert gas. The shape of the exterior case is not particularly limited and may be, for example, cylindrical or prismatic (especially a quadrangular prism).

[0021] <<Method for manufacturing a capacitor>> The present disclosure also includes an invention of a method for manufacturing a capacitor, which provides a thin-film polymer laminated capacitor element, provides an exterior case that houses uncured rubber or curable resin and has an opening, houses the thin-film polymer laminated capacitor element in the exterior case and covers the lower end portion of the thin-film polymer laminated capacitor element with uncured rubber or curable resin, places the exterior lid so as to cover the opening of the exterior case and joins them to seal the exterior case, and after sealing the exterior case, cures the uncured rubber or curable resin, includes.

[0022] By covering only the "lower end portion" of the thin-film polymer laminated capacitor element with uncured rubber or curable resin, the capacitor element is fixed to the exterior case. This enables weight reduction of the capacitor. Also, since the amount of resin is reduced, problems caused by the resin (for example, generation of decomposition gas due to deterioration by the ambient temperature environment) can be reduced.

[0023] Also, in the manufacturing method of the present invention, a thin-film polymer laminated capacitor element is provided. As described above, since the thin-film polymer laminated capacitor is superior in heat resistance to a conventional film capacitor, it has the advantages that a rubber or curable resin with a high curing temperature can be used for fixing the element and that a high operating guarantee temperature can be obtained.

[0024] Furthermore, in the manufacturing method of the present invention, since the rubber / resin is cured after joining the exterior case and the exterior lid, it is possible to prevent the load associated with this joining from being applied to the terminal portion (such as a connection member) of the capacitor.

[0025] FIG. 2 (Fig. 2) shows an example of a method for manufacturing a capacitor according to the present invention. In the method of FIG. 2, first, a thin-film polymer laminated capacitor element is provided (left side of (1) in the figure). In the embodiment of FIG. 2, the provided thin-film polymer laminated capacitor element 201 is connected to the exterior lid 202 via connection members 203a and 203b. By providing the thin-film polymer laminated capacitor element in a state of being connected to the exterior lid in advance in this way, the manufacturing of the capacitor can be simplified and the manufacturing accuracy can be improved. The connection members 203a and 203b may be made of a highly rigid material, whereby the position of the thin-film polymer laminated capacitor element 201 with respect to the exterior lid 202 is fixed. This thin-film polymer laminated capacitor element 201 has electrode lead-out portions 204a and 204b on two side main surfaces, respectively. The exterior lid 202 is made of metal.

[0026] In the method of FIG. 2, also, an exterior case 205 containing uncured rubber or curable resin 206 is provided (right side of (1) in the figure). The height of the cured rubber or curable resin 206 may be 10 to 50% of the height of the cavity of the exterior case (or the height of the internal space formed later by the exterior case and the exterior lid), or may be 20 to 40%. The exterior case 205 is made of metal.

[0027] Then, in the method of FIG. 2, the thin-film polymer laminated capacitor element 201 fixed to the exterior lid 202 is housed in the exterior case 205, and the lower end portion of the thin-film polymer laminated capacitor element 201 is covered with the uncured rubber or curable resin 206 (arrow in (1) of the figure). At the same time, the exterior lid is placed on top of the opening side of the exterior case to cover the opening ( (2) in the figure).

[0028] In the method of FIG. 2, the thin-film polymer laminated capacitor element 201 is sealed inside the internal space by joining the exterior case 205 and the exterior lid 202 to each other (FIG. (3)), and then, uncured rubber or curable resin 206 is cured to manufacture the capacitor 20 (step (4)). In FIG. 2, the joining of the exterior case 205 and the exterior lid 202 is performed by double winding. It is preferable that the uncured rubber or curable resin does not generate gas during curing. It is desirable that the internal space is in a vacuum (reduced pressure) state or filled with an inert gas.

[0029] Hereinafter, each component of the present invention will be described in more detail.

[0030] <Thin-film polymer laminated capacitor element> The capacitor of the present invention includes a thin-film polymer laminated capacitor element. The thin-film polymer laminated capacitor element has a structure in which a dielectric layer (resin thin-film layer) containing a thermosetting resin and an electrode layer (metal thin-film layer) containing a metal are alternately laminated.

[0031] FIG. 4 is a schematic perspective view of the thin-film polymer laminated capacitor 1. The thin-film polymer laminated capacitor 1 has a laminate 2 in which a resin thin-film layer and a metal thin-film layer (internal electrode metal layer) are alternately laminated, and two electrode lead-out portions 3 and 4 are attached to this laminate 2. In the figure, the dimensional directions of "width W", "height H", and "depth D" are shown.

[0032] (Dimensions of the capacitor element) The capacitor element can have a prismatic shape. In particular, a capacitor having a prismatic shape has a relatively large "depth D" with respect to the "width W" and "height H", and electrode lead-out portions are applied in a planar manner to two opposing side surfaces (see FIG. 4). Here, "relatively large" means that "depth D" has a length at least 1.5 times that of each of "width W" and "height H", preferably at least 2.0 times, and more preferably at least 2.5 times the depth.

[0033] For example, a capacitor element according to one embodiment of the present invention has a width of 16 mm, a height of 30 mm, and a depth of 75 mm.

[0034] <Electrode lead-out portion> The thin-film polymer laminated capacitor element includes electrode lead-out portions formed by spraying metal on both end faces thereof. The electrode lead-out portions may have, for example, a surface of tin metallicon.

[0035] In one embodiment of the present invention, the electrode lead-out portions of the thin-film polymer laminated capacitor element are arranged to face the inner side walls of the exterior case. In this case, since both of the two electrode lead-out portions at both ends of the capacitor element can be brought close to the two terminal portions of the exterior lid, the assembly of the capacitor can be facilitated. Also, it becomes possible to shorten the connection members, and it also becomes easy to make the dimensions of the two connection members the same. Thereby, for example, it becomes possible to reduce the ESR and ESL of the capacitor.

[0036] Details of the structure of the thin-film polymer laminated capacitor element will be described later. For specific examples of the thin-film polymer laminated capacitor element, reference can be made to, for example, International Publication No. 2015 / 118693.

[0037] <Exterior case> The capacitor of the present invention includes an exterior case. The exterior case can accommodate the thin-film polymer laminated capacitor element and has a cavity (hollow) for accommodating the capacitor element and an opening.

[0038] In one embodiment of the present invention, the exterior case is made of metal. In this case, for example, compared with the case of using an exterior case made of a plastic material, a capacitor having better heat resistance and moisture resistance can be provided.

[0039] The shape of the exterior case is not particularly limited, and for example, it may be cylindrical or prismatic (especially a quadrangular prism). For example, the exterior case has a bottom surface and side surfaces, and these bottom and side surfaces define the above-mentioned cavity (hollow). Further, the exterior case may have an opening in a portion corresponding to the upper surface. Through this opening, the capacitor element can be housed in the cavity.

[0040] The cavity of the exterior case may have a size corresponding to the size of the capacitor element. For example, it may have a volume that is 1.5 to 3 times the volume of the capacitor element. Also, for example, the exterior case may have a diameter of 10 mm to 500 mm, 20 mm to 200 mm, or even 30 mm to 100 mm. Also, for example, the exterior case may have a height of 10 mm to 500 mm, 50 mm to 200 mm, or even 75 mm to 150 mm.

[0041] Also, the walls (especially the side walls and the bottom wall) constituting the exterior case may have a thickness of, for example, 0.1 mm to 0.5 mm, 0.2 to 0.4 mm, or even 0.2 to 0.3 mm.

[0042] In one particularly preferred embodiment, the exterior case is a metal can, especially a steel can or an aluminum can.

[0043] <Exterior lid> The capacitor of the present invention includes an exterior lid. The exterior lid can be joined to the exterior case (especially the opening of the exterior case) to form a sealed space (internal space). By joining the exterior lid to the exterior case having the capacitor element housed in the cavity, the capacitor element can be sealed.

[0044] In one embodiment of the present invention, the exterior lid is made of metal. In this case, for example, compared with the case of using an exterior lid made of a plastic material, a capacitor with better heat resistance and moisture resistance can be provided.

[0045] The shape of the exterior lid is not particularly limited, and for example, it may be disk-shaped or plate-shaped.

[0046] In one particularly preferred embodiment, the outer lid is made of steel or aluminum.

[0047] When the outer lid and the outer case are made of metal, the outer case and the outer lid can be sealed by double crimping, so that the environmental resistance of the capacitor can be further improved.

[0048] In one embodiment of the present invention, the joining of the outer lid and the outer case is double crimping. Thereby, airtightness can be maintained over a long period of time.

[0049] <Cured rubber or curable resin> The cured rubber or curable resin fixes the thin film polymer laminated capacitor element to the outer case.

[0050] In the capacitor of the present invention, the cured rubber or curable resin covers the lower end portion of the thin film polymer laminated capacitor element.

[0051] Here, the "lower end portion" generally refers to the portion of the capacitor element disposed in the outer case that is close to the bottom surface side of the outer case. On the other hand, the "upper end portion" refers to the portion of the capacitor element disposed in the outer case that is close to the upper surface (particularly the opening) of the outer case. Note that the portion of the capacitor element between the lower end portion and the upper end portion can be called the "central portion".

[0052] For example, a capacitor element disposed in an exterior case can be divided into three parts along the direction from the bottom surface side to the upper surface side (particularly the opening side) of the exterior case, and can be respectively referred to as the "lower end portion", the "central portion", and the "upper end portion" from the bottom surface side. In this case, with respect to the height of the capacitor element along the direction from the bottom surface side to the upper surface side (particularly the opening side), the "lower end portion" can have a height that is covered by rubber or a curable resin, for example, a height such that at least 5% of the capacitor element is covered by rubber or a curable resin. This height of the "lower end portion" can be more preferably 5 to 40%, particularly preferably 10 to 30% of the overall height of the capacitor element. The size (particularly the height) of the lower end portion covered by the cured rubber or curable resin can be determined according to the amount of rubber or curable resin required for fixing the capacitor element and the size of the desired internal space, etc.

[0053] Similarly, among the overall height of the capacitor element along the direction from the bottom surface side to the upper surface side (particularly the opening side), the "upper end portion" of the capacitor element can be at least 5% in height. The "upper end portion" can be more preferably 10 to 30%, particularly preferably 20 to 30% of the overall height of the capacitor element. The connecting member can be connected to the upper end portion or the central portion of the capacitor element.

[0054] In one embodiment of the present invention, the rubber or curable resin does not release a reaction gas during curing. In this case, when curing is performed after sealing the capacitor in the exterior case, no gas is released into the internal space of the capacitor, so airtightness can be maintained and deformation of the exterior case can be prevented.

[0055] In one embodiment of the present invention, the rubber or curable resin contains at least one selected from RTV silicone rubber, epoxy resin, urethane resin, and diallyl phthalate resin. RTV silicone rubber not only does not release a reaction gas during curing, but also has excellent thermal conductivity and flame retardancy, and can promote heat dissipation. Also, due to its rubbery properties, it adheres to the uneven shape, and the effects of absorbing impact and promoting heat dissipation can be obtained.

[0056] In one embodiment of the present invention, rubber or curable resin adheres not only to the bottom of the exterior case but also to the inner sidewall of the exterior case and the inner wall of the exterior lid. This leads to more stable joining of the exterior lid and the exterior case, improved sealing performance, and protection of the inner wall.

[0057] <Internal space> According to the capacitor of the present invention, the thin-film polymer laminated capacitor element is sealed in the internal space formed by the exterior case and the exterior lid joined to each other.

[0058] In one embodiment of the present invention, the internal space in the exterior case is either vacuum or filled with an inert gas. This can protect the capacitor from moisture and heat. Also, since there is little oxygen in the internal space, oxidation degradation and thermal oxidation degradation of the capacitor element (dielectric resin) and the rubber or cured resin for fixing can be prevented. Preferably, it is filled with an inert gas having high thermal conductivity, thereby promoting heat dissipation of the capacitor heated by current superposition. Examples of the inert gas include nitrogen gas, helium gas, or a mixed gas thereof. Helium gas or a mixed gas of helium gas and nitrogen gas is preferable because it has particularly high thermal conductivity among inert gases.

[0059] In one embodiment of the present invention, the height H of the cured rubber or curable resin in the internal space R is 10 to 50% of the height H of the internal space I and more preferably 20 to 40%. In this case, the amount of resin present in the internal space is reduced, so problems caused by the resin (for example, generation of decomposition gas due to degradation by the ambient temperature environment) can be reduced or even avoided. Also, the weight of the capacitor can be reduced. Especially in in-vehicle applications, weight reduction of components is important, so the added value can be increased by reducing the weight of the capacitor.

[0060] The "height" of the internal space is generally equal to the height of the interior of the exterior case (i.e., the cavity). For example, the "height" of the internal space is equal to the height from the inner side surface of the bottom surface of the exterior case to the opening of the exterior case (or the inner wall surface of the exterior lid).

[0061] <Connecting member> In one embodiment of the present invention, the capacitor has a connecting member for electrically connecting the thin-film polymer laminated capacitor element to the outside. The connecting member extends through the exterior lid, one end portion of the connecting member is connected to the thin-film polymer laminated capacitor element, and the other end portion of the connecting member is disposed outside the capacitor.

[0062] In one embodiment of the present invention, the connecting member is composed of an integral member. This embodiment is advantageous in terms of strength reliability, and is also advantageous in terms of manufacturing cost and tact time.

[0063] In another embodiment of the present invention, the connecting member is composed of a plurality of members, and among these plurality of members, at least the member connected to the capacitor element is composed of an integral member. This embodiment is relatively advantageous in terms of strength reliability, and is also relatively advantageous in terms of manufacturing cost and tact time. In this embodiment, for example, the connecting member has a first connecting member (e.g., a terminal portion) and a second connecting member (e.g., a lead portion), the first connecting member is a member that passes through the exterior lid and has two end portions protruding in opposite directions from the exterior lid, and the second connecting member is a member that connects the inner space side end portion of the first connecting member and the capacitor element.

[0064] In one embodiment of the present invention, the portion of the connecting member adjacent to the inner wall of the exterior lid (the so-called "root" portion) is covered with rubber or a curable resin. This embodiment is advantageous in terms of increasing (reinforcing) strength. This can be achieved, for example, by rotating or inverting the exterior case after sealing the thin-film polymer laminated capacitor element and before curing the uncured rubber or curable resin, thereby causing the uncured rubber or curable resin to adhere to the root portion.

[0065] In one embodiment of the present invention, the connecting member is made of a highly rigid material (rigid material). As a result, since the capacitor element is fixed to the outer lid by leads, the connection between the outer lid and the thin-film polymer laminated capacitor element becomes easy during the manufacturing process, and stability within the outer case is obtained. Further, by using a rigid material, the positional relationship between the outer lid and the capacitor element can be determined in advance before the capacitor element is housed in the outer case, so that errors between products are reduced and quality improvement can be expected. Note that "highly rigid" particularly means having such a rigidity that when the outer lid is fixed to the capacitor element via the connecting member, the positional relationship between the outer lid and the connecting member remains immovable during the manufacturing process of the capacitor. A person skilled in the art can appropriately select a material and / or size that satisfies this condition.

[0066] The connecting member may be made of, for example, copper, nickel, aluminum, or an alloy thereof, and may be a metal wire, a rod-shaped metal member, or a metal plate. For connection to the element, the end portion on the element side of the connecting member that is a metal wire or a rod-shaped metal member may have a flat shape. For example, gold plating or the like may be applied on the surface of the connecting member to enhance solderability. Plating that melts during soldering (such as tin plating) is less preferable from the viewpoint of maintaining good airtightness at the joint portion between the lid and the lead.

[0067] In one particularly preferred embodiment, the connecting member is a metal lead, and in particular, a copper lead. The lead may have a diameter of, for example, 0.5 mm to 5.0 mm.

[0068] In one embodiment of the present invention, the capacitor has two connecting members respectively connected to two electrode lead-out portions of the capacitor element, and the connection portions between these two connecting members and the thin-film polymer laminated capacitor element are all present outside the cured rubber or curable resin. As a result, since the amount of resin does not cover the entire element, weight reduction of the capacitor is achieved.

[0069] In one embodiment of the present invention, the connection portion between the connection member and the thin-film polymer laminated capacitor element is present at the upper end portion of the thin-film polymer laminated capacitor element. As a result, since two relatively short connection members of the same length are prepared, the structure is simplified, and the labor and cost of lead provision can be reduced.

[0070] The method of joining the connection member (particularly the terminal portion of the connection member) and the exterior lid (particularly a steel lid or an aluminum lid) is not particularly limited, and for example, it may be a hermetic seal (airtight seal), particularly a glass seal.

[0071] In the case of a hermetic seal, specifically, for example, the space between the terminal portion made of aluminum or copper inserted into the opening provided in the exterior lid and the exterior lid is filled with glass and sealed. For example, glass sealing by the GTAS (registered trademark) technology of SCHOTT can be mentioned.

[0072] <Use of the capacitor> In one embodiment of the present invention, the capacitor according to the present invention can be continuously used at 125°C. Here, "continuously usable" means that when continuously used for at least 1000 hours, there is no substantial deterioration in the performance (particularly the capacitance) of the capacitor. "Substantial deterioration" particularly means that the reduction rate of the performance (particularly the capacitance) of the capacitor is less than 10%, less than 5%, particularly less than 2%.

[0073] In one embodiment of the present invention, the capacitor according to the present invention can be for in-vehicle use. [[ID=2I]]

[0074] In one embodiment of the present invention, the capacitor according to the present invention can be used at a voltage of 200 V or more.

[0075] In one embodiment of the present invention, the capacitor according to the present invention can be a capacitor for power electronics.

[0076] <<Manufacturing method of the capacitor>> The manufacturing method of the capacitor according to the present disclosure is not particularly limited. The capacitor according to the present disclosure can be manufactured, for example, by the following manufacturing method of the capacitor according to the present disclosure.

[0077] The manufacturing method of the capacitor of the present invention providing a thin-film polymer laminated capacitor element (capacitor element providing step), providing an exterior case that contains uncured rubber or curable resin and has an opening (exterior case providing step), placing the thin-film polymer laminated capacitor element in the exterior case and covering the lower end portion of the thin-film polymer laminated capacitor element with uncured rubber or curable resin (accommodating step), placing an exterior lid so as to cover the opening of the exterior case and joining them to seal the exterior case (sealing step), and after sealing the exterior case, curing the uncured rubber or curable resin (curing step), is included.

[0078] Regarding each component (for example, capacitor element, exterior case, exterior lid, rubber or curable resin, etc.) in the manufacturing method of the capacitor according to the present disclosure, the above description regarding the capacitor according to the present disclosure can be referred to.

[0079] <Capacitor element providing step> The manufacturing method of the capacitor of the present invention includes providing a thin-film polymer laminated capacitor element.

[0080] The thin-film polymer laminated capacitor element will be described later. For specific examples of the thin-film polymer laminated capacitor element, for example, reference can be made to International Publication No. 2015 / 118693.

[0081] In one embodiment of the present invention, when providing a thin-film polymer laminated capacitor element, a thin-film polymer laminated capacitor element fixed to an exterior lid is provided. Thereby, the connection between the exterior lid and the thin-film polymer laminated capacitor element becomes easy. Further, before accommodating the capacitor element in the exterior case, the positional relationship between the exterior lid and the capacitor element can be determined in advance, so that the positioning error is reduced and quality improvement can be expected.

[0082] In one embodiment of the present invention, the thin-film polymer laminated capacitor element is fixed to the exterior lid by a connection member for electrically connecting the thin-film polymer laminated capacitor element to the outside.

[0083] In one embodiment of the present invention, the connection portion between the connection member and the capacitor element exists at the upper end portion of the capacitor element. Thereby, since two relatively short connection members having the same length are prepared, the structure is simplified, and the labor and cost for providing the connection member can be reduced.

[0084] <Exterior case providing step> The manufacturing method of the present invention includes providing an exterior case containing uncured rubber or curable resin.

[0085] In one embodiment of the present invention, the rubber or curable resin does not emit reaction gas during curing. In this case, when curing is performed after sealing the capacitor in the exterior case, gas is not released into the internal space of the capacitor, so that airtightness can be maintained and deformation of the exterior case can be prevented.

[0086] In one embodiment of the present invention, at least one selected from the group consisting of RTV silicone rubber, epoxy resin, urethane resin, and diallyl phthalate resin is used as the rubber or curable resin. RTV silicone rubber not only does not emit reaction gas during curing, but also has excellent thermal conductivity and flame retardancy, and can promote heat dissipation. Further, due to its rubber properties, it adheres to the uneven shape, and the effects of absorbing impact and promoting heat dissipation can be obtained.

[0087] In one embodiment of the present invention, the exterior case is made of metal. In this case, a capacitor with better heat resistance and moisture resistance can be provided as compared with the case where an exterior case made of, for example, a plastic material is used.

[0088] The uncured rubber or curable resin housed in the exterior case may fill the interior of the exterior case at a height such that, in the completed capacitor, the cured rubber or curable resin occupies 10% to 50% of the height of the cavity of the exterior case (or the internal space of the capacitor), and particularly may fill the interior of the exterior case at a height such that it occupies 20% to 40%.

[0089] <Storage step> The manufacturing method of the present invention includes housing a thin film polymer laminated capacitor element in an exterior case and covering the lower end portion of the thin film polymer laminated capacitor element with uncured rubber or curable resin.

[0090] In this step, for example, the capacitor element is inserted into the cavity of the exterior case through the opening of the exterior case so that the lower end portion of the capacitor element is immersed in the uncured rubber or curable resin disposed at the bottom of the exterior case. At this time, by appropriately conforming the capacitor element to the uncured rubber or curable resin, generation of air bubbles can be avoided.

[0091] <Sealing step> The manufacturing method of the present invention includes sealing the exterior case by disposing and joining an exterior lid so as to cover the opening of the exterior case.

[0092] In one embodiment of the present invention, the exterior lid is made of metal. In this case, a capacitor with better heat resistance and moisture resistance can be provided as compared with the case where an exterior lid made of, for example, a plastic material is used.

[0093] When the exterior lid and the exterior case are made of metal, the exterior case and the exterior lid can be sealed by double caulking, so the environmental resistance of the capacitor can be further improved.

[0094] In one embodiment of the present invention, the joining of the exterior lid and the exterior case is a double winding and tightening. Thereby, airtightness can be maintained over a long period of time.

[0095] In one embodiment of the present invention, the exterior case is sealed under vacuum (or reduced pressure), or filled with an inert gas and then sealed. Thereby, the capacitor can be protected from moisture and heat. Also, since there is almost no oxygen in the internal space, oxidation degradation and thermal oxidation degradation of the capacitor element (dielectric resin) and the rubber or cured resin for fixing can be prevented. Preferably, it is filled with an inert gas having high thermal conductivity, thereby promoting heat dissipation.

[0096] Examples of the inert gas include nitrogen gas, helium gas, or a mixed gas thereof. Helium gas, or a mixed gas of helium gas and nitrogen gas, is preferable because it has a particularly high thermal conductivity among inert gases.

[0097] <Curing process> The manufacturing method of the present invention includes curing uncured rubber or curable resin after sealing the exterior case.

[0098] The curing conditions of the rubber or curable resin are not particularly limited and can be appropriately determined according to the type and / or amount, etc. For example, when using RTV silicone rubber as the rubber or curable resin, the curing of the rubber or curable resin can be performed at a temperature of 80 to 120 °C for 30 minutes to 3 hours.

[0099] In one embodiment of the present invention, after sealing the thin film polymer laminated capacitor element and before curing the uncured rubber or curable resin, the exterior case is rotated or inverted to attach the uncured rubber or curable resin to the inner side wall of the exterior case and the inner wall of the exterior lid. This leads to a more stable joining of the exterior lid and the exterior case, an improvement in airtightness, and the protection of the inner wall and the internal space.

[0100] In one embodiment of the present invention, after sealing the thin-film polymer laminated capacitor element and before curing the uncured rubber or curable resin, the outer case is rotated or inverted to cover the portion of the connection member adjacent to the inner wall of the outer lid (so-called "root" portion) with rubber or curable resin. This embodiment is advantageous in that it enhances (reinforces) the strength of the physical or electrical connection by the connection member.

[0101] <Orientation of the capacitor element> In one embodiment of the present invention, when accommodating the thin-film polymer laminated capacitor element in the outer case, the thin-film polymer laminated capacitor element is accommodated such that the electrode lead-out portion of the thin-film polymer laminated capacitor element faces the inner side wall of the outer case. As a result, the distance between the electrode lead-out portion of the capacitor element and the terminal portion attached to the outer lid becomes short and symmetric, facilitating assembly and enabling reduction of errors in the manufacturing process and thereby improving quality. Also, it becomes possible to reduce the ESR and ESL of the capacitor.

[0102] (Thin-film polymer laminated capacitor element) The thin-film polymer laminated capacitor element has a structure in which a dielectric layer containing resin (resin thin-film layer) and an electrode layer containing metal (metal thin-film layer) are alternately laminated.

[0103] For example, the thin-film polymer laminated capacitor element can be manufactured by a method including the following: (1) A step of forming a monomer layer by vapor-depositing a monomer in a vacuum chamber and then irradiating the monomer layer with an electron beam to cure the monomer layer to form a resin thin-film layer, (2) A step of forming a metal thin-film layer by vapor-depositing a metal material, (3) A step of manufacturing a laminate in which a resin thin-film layer and a metal thin-film layer are alternately laminated on a rotating drum by alternately repeating the process on the rotating drum.

[0104] When forming the resin thin-film layer, as the monomer, for example, a dimethacrylate compound having an alicyclic hydrocarbon skeleton can be used to form the monomer layer.

[0105] The thin-film polymer laminated capacitor may have 10 to 10,000 layers, 50 to 5,000 layers, or 100 to 2,000 layers.

[0106] The dielectric layer containing resin is often formed using a monomer having an acrylic group or a methacrylic group or the like. Examples of such a monomer include dicyclopentadienylmethanol diacrylate, tricyclodecane dimethanol diacrylate, and tricyclodecane dimethanol dimethacrylate.

[0107] In one particularly preferred embodiment, the dielectric layer containing resin has a polymer structure formed by polymerizing a first monomer which is a monofunctional monomer, a second monomer which is a bifunctional monomer, and a third monomer which is a polyfunctional monomer having three or more functional groups. Here, the first monomer may include 2-(biphenyl-2-yloxy)-ethyl acrylate, 4-phenylbenzyl acrylate, stearyl acrylate, or stearyl methacrylate; the second monomer may include tricyclodecane dimethanol diacrylate or tricyclodecane dimethanol dimethacrylate; and / or the third monomer may include triallyl isocyanurate.

[0108] The dielectric layer containing resin may have a thickness of 10 nm to 3,000 nm, preferably 100 to 1,500 nm.

[0109] Examples of the metal material constituting the electrode layer containing metal include at least one selected from the group consisting of Al, Cu, Zn, Sn, Au, Ag, Pt, and combinations thereof. The metal material constituting the metal thin film layer is preferably aluminum.

[0110] The electrode layer containing metal may have a thickness of 1 nm to 100 nm, preferably 10 to 40 nm. Also, the metal thin film layer preferably has a deposition resistance value of 1 to 50 Ω / □, 5 to 40 Ω / □, or 5 to 30 Ω / □.

[0111] Preferably, the thin film polymer laminated capacitor has a relative dielectric constant of 2.0 or more when measured at 25°C and 1 kHz. This relative dielectric constant is more preferably 2.1 or more, 2.2 or more, 2.3 or more, or 2.5 or more. The upper limit of this relative dielectric constant is not particularly limited, but it may be 5.0 or less.

[0112] The relative dielectric constant at 25°C and 1 kHz can be calculated based on the capacitance measured using an LCR meter, as well as the electrode area and the thickness of the dielectric.

[0113] Also, preferably, the thin film polymer laminated capacitor has a tanδ (also referred to as dielectric tangent or loss factor) of less than 1.0% when measured at 25°C and 1 kHz. This tanδ is more preferably 0.9% or less, 0.85% or less, 0.8% or less, 0.7% or less, 0.6% or less, 0.5% or less, 0.4% or less, 0.3% or less, 0.2% or less, or 0.1% or less. The lower limit of this tanδ is not particularly limited, but it may be 0.05% or more.

[0114] The tanδ at 25°C and 1 kHz can be measured using an LCR meter.

[0115] Furthermore, preferably, the thin film polymer laminated capacitor has a tanδ of less than 2.0% when measured at 105°C and 1 kHz. This tanδ is more preferably 1.5% or less, and even more preferably 1.2% or less. The lower limit of this tanδ is not particularly limited, but it may be 0.1% or more.

[0116] The tanδ at 105°C and 1 kHz can be measured using an LCR meter.

[0117] Preferably, the thin-film polymer laminated capacitor exhibits a water absorption rate of 0.2 to 0.9%. This water absorption rate is particularly 0.25 to 0.80%, more particularly 0.30 to 0.70%. This water absorption rate can be measured by the following method: Place the capacitor with the electrode lead-out part cut off in a thermo-hygrostat chamber at a temperature of 60°C and a relative humidity of 90% and conduct a moisture absorption test by leaving it stationary for 100 hours, then measure the weight change rate (%) of the capacitor, and use this as the water absorption rate (%) of the capacitor: Weight change rate (%) = 100×(weight after moisture absorption test - weight before moisture absorption test) / weight before moisture absorption test.

Example

[0118] <<Example 1 and Comparative Example 1>> In Example 1 and Comparative Example 1, capacitors were fabricated and their physical properties were evaluated.

[0119] <Example 1> The capacitor specifications and exterior specifications of the fabricated capacitors are summarized in Table 1.

Table 1

[0120] The manufacturing procedure of the capacitor according to the example includes the following: (1) Join a connection member integrated with an exterior lid to the electrode lead-out part (surface tin metallization) of the capacitor element by welding (the tip of the connection member at the welded part is pre-crushed and thinly widened). (2) Put RTV rubber into the exterior case. (3) Under a reduced-pressure environment, accommodate the capacitor element and the exterior lid in the exterior case. (4) Join the exterior lid and the exterior case by double winding and seal them airtight. (5) Thermally cure the RTV rubber at 100°C for 1.5 hours.

[0121] Figure 3 shows the results of the moisture resistance life test for an example of a capacitor according to the present invention and its comparative example. The moisture resistance life test was carried out by applying a voltage of 850 V under the conditions of a temperature of 85 °C and a relative humidity (RH) of 85%. This experiment was conducted 5 times, and in Figure 3, the averages thereof are plotted. The plots of black circles represent the results of the examples, and the plots of black triangles represent the comparative examples. The vertical axis represents the capacitance change rate, and the horizontal axis represents the elapsed time (unit: hours).

[0122] In Figure 3, in Comparative Example 1, the capacitance disappeared after 250 hours, while in Example 1, there was almost no performance degradation even after a moisture resistance life test lasting 5000 hours, indicating very excellent environmental resistance.

Claims

1. A thin-film polymer laminated capacitor element, an exterior case for housing the thin-film polymer laminated capacitor element, a cured rubber or curable resin that fixes the thin-film polymer laminated capacitor element to the exterior case, and an exterior lid characterized by comprising: the thin-film polymer laminated capacitor element is sealed within an internal space formed by the exterior case and the exterior lid joined to each other, the cured rubber or curable resin covers a lower end portion of the thin-film polymer laminated capacitor element, a capacitor.

2. The capacitor according to claim 1, wherein the exterior case and the exterior lid are made of metal.

3. The capacitor according to any one of claims 1 or 2, wherein the joining of the exterior lid and the exterior case is a double crimping.

4. The capacitor according to claim 1 or 2, wherein the internal space is vacuum or filled with an inert gas.

5. The capacitor according to claim 4, wherein the inert gas is nitrogen gas, helium gas, or a mixed gas thereof.

6. The capacitor according to claim 1 or 2, wherein the rubber or curable resin does not emit a reaction gas during curing.

7. The capacitor according to claim 1 or 2, wherein the rubber or curable resin contains at least one selected from RTV silicone rubber, epoxy resin, urethane resin, and diallyl phthalate resin.

8. The height H in the internal space of the hardened rubber or the curable resin Ｒ is 10 to 50% of the height H of the internal space I The capacitor according to claim 1 or claim 2.

9. The capacitor according to claim 1 or 2, wherein the rubber or curable resin adheres to at least a part of the inner side wall of the exterior case and the inner wall of the exterior lid.

10. having a connection member for electrically connecting the thin-film polymer laminated capacitor element to the outside, the connection member extends through the exterior lid, one end portion of the connection member is connected to the thin-film polymer laminated capacitor element in the internal space, the other end portion of the connection member is disposed outside the capacitor, the capacitor according to claim 1 or 2.

11. the rubber or curable resin adheres to at least a part of the inner side wall of the exterior case and the inner wall of the exterior lid, and a portion of the connection member passing through the exterior lid and adjacent to the inner wall of the exterior lid is covered by the rubber or curable resin, the capacitor according to claim 10.

12. The capacitor according to claim 10, wherein the connection member is composed of an integral member.

13. The capacitor according to claim 10, wherein the connection member is composed of a plurality of members connected to each other, and at least among these plurality of members, the member connected to the thin-film polymer laminated capacitor element in the internal space is composed of an integral member.

14. The capacitor according to claim 10, wherein the connection member is made of a material with high rigidity.

15. The capacitor according to claim 1 or claim 2, which can be continuously used at 125 °C.

16. The capacitor according to claim 1 or claim 2, which is a capacitor for use at a voltage of 200 V or higher.

17. A method for manufacturing a capacitor, providing a thin-film polymer laminated capacitor element, providing an exterior case that houses uncured rubber or curable resin and has an opening, housing the thin-film polymer laminated capacitor element in the exterior case and covering a lower end portion of the thin-film polymer laminated capacitor element with the uncured rubber or the curable resin, arranging and joining an exterior lid so as to cover the opening of the exterior case to seal the exterior case, and curing the uncured rubber or the curable resin after sealing the exterior case, comprising a method.

18. The method according to claim 17, wherein the exterior case and the exterior lid are made of metal, and the exterior lid and the exterior case are joined to each other by double winding.

19. The method according to claim 17 or claim 18, wherein the exterior case is sealed under vacuum or filled with an inert gas and then sealed.

20. When providing the thin-film polymer laminated capacitor element, providing the thin-film polymer laminated capacitor element pre-fixed to the exterior lid, wherein the thin-film polymer laminated capacitor element is fixed to the exterior lid by a connection member for electrically connecting the thin-film polymer laminated capacitor element to the outside, and the connection member extends through the exterior lid The method according to any one of claims 17 or 18.

21. After sealing the thin-film polymer laminated capacitor element and before curing the uncured rubber or curable resin, by rotating or inverting the exterior case, the uncured rubber or curable resin is adhered to the inner side wall of the exterior case and the inner wall of the exterior lid, and a portion of the connecting member passing through the exterior lid and adjacent to the inner wall of the exterior lid is covered with the rubber or curable resin. The method according to claim 20.

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