Caseless capacitor

Abstract

To provide a caseless capacitor in which heat generated in a capacitor element is easily dissipated to the outside.SOLUTION: A caseless capacitor 1 comprises: a main body unit 5 extending in a first direction D1, including a first end face 31 at one side in the first direction D1 and a second end face 32 at the other side in the first direction D1 and including a first plane 41 at one side of a second direction D2 and a second plane 42 at the other side in the second direction D2; a capacitor element 2 including a first end face electrode 61 provided on the first end face 31 and a second end face electrode 62 provided on the second end face 32; a sealing unit 7 sealing the capacitor element 2; and a metal plate 9 opposed with the second plane 42 of the capacitor 2 while interposing an insulation layer 8 therebetween, fixed to the insulation layer 8 and exposed to an outside. A flatness ratio (B / A) which is a value of a ratio of a width (B) of the capacitor element 2 in a third direction D3 with respect to an inter-plane distance (A) between the first plane 41 and the second plane 42 is 2.0 or more and 10.0 or less.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure generally relates to a case-less capacitor, and more particularly to a case-less capacitor provided with a sealing portion.

Background Art

[0002] Patent Document 1 discloses a dry metallized film capacitor. This dry metallized film capacitor is formed by laminating and winding a pair of metallized films, joining an external lead wire to a capacitor element in which electrode lead-out portions are formed by spraying metallicon metal on both end faces, and housing the capacitor element in a resin case and filling and curing a thermosetting resin. In the above dry metallized film capacitor, the external lead wire has a key-shaped configuration that bends toward the capacitor element side, a support plate is inserted into the L-shaped portion of the external lead wire, and is housed and fixed in the resin case.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the dry metallized film capacitor of Patent Document 1, since a resin case and a support plate are used in addition to the thermosetting resin, there is a problem that it is difficult to reduce the weight. Further, since the capacitor element is housed in the resin case and covered with the support plate, there is also a problem that it is difficult to release the heat generated in the capacitor element to the outside.

[0005] An object of the present disclosure is to provide a case-less capacitor that easily releases the heat generated in the capacitor element to the outside.

Means for Solving the Problems

[0006] A caseless capacitor according to a first aspect of the present disclosure comprises: a main body portion extending in a first direction, having a first end face on one side in the first direction and a second end face on the other side in the first direction, and having a first plane on one side in a second direction perpendicular to the first direction and a second plane on the other side in the second direction; a capacitor element having a first end face electrode provided on the first end face and a second end face electrode provided on the second end face; a sealing portion for sealing the capacitor element; and a metal plate facing the second plane of the capacitor element via an insulating layer, fixed to the insulating layer, and exposed to the outside. The flattening ratio (B / A), which is the ratio of the width (B) of the capacitor element along a third direction perpendicular to the first and second directions to the plane-to-plane distance (A) between the first plane and the second plane, is 2.0 or more and 10.0 or less.

[0007] A caseless capacitor according to a second aspect of the present disclosure comprises: a main body portion extending in a first direction, having a first end face on one side in the first direction and a second end face on the other side in the first direction, and having a first plane on one side in a second direction perpendicular to the first direction and a second plane on the other side in the second direction; a capacitor element having a first end face electrode provided on the first end face and a second end face electrode provided on the second end face; a sealing portion for sealing the capacitor element; and a metal plate facing the second plane of the capacitor element via an insulating layer, fixed to the insulating layer and exposed to the outside. The plane-to-plane distance between the first plane and the second plane is 10 mm or more and 30 mm or less.

[0008] A caseless capacitor according to a third aspect of the present disclosure comprises: a main body portion extending in a first direction, having a first end face on one side in the first direction and a second end face on the other side in the first direction, and having a first plane on one side in a second direction perpendicular to the first direction and a second plane on the other side in the second direction; a capacitor element having a first end face electrode provided on the first end face and a second end face electrode provided on the second end face; a sealing portion for sealing the capacitor element; and a metal plate facing the second plane of the capacitor element via an insulating layer, fixed to the insulating layer and exposed to the outside. The total length of the capacitor element along the first direction is 10 mm or more and 30 mm or less.

[0009] A caseless capacitor according to a fourth aspect of the present disclosure comprises: a main body portion extending in a first direction, having a first end face on one side in the first direction and a second end face on the other side in the first direction, and having a first plane on one side in a second direction perpendicular to the first direction and a second plane on the other side in the second direction; a capacitor element having a first end face electrode provided on the first end face and a second end face electrode provided on the second end face; a sealing portion that seals the capacitor element; and a metal plate facing the second plane of the capacitor element via an insulating layer, fixed to the insulating layer and exposed to the outside. The thickness of the first end face electrode and the second end face electrode is 0.5 mm or more and 1.5 mm or less. [Effects of the Invention]

[0010] According to this disclosure, the heat generated by the capacitor element is easily released to the outside. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1A is a schematic perspective view showing a caseless capacitor according to this embodiment. Figure 1B is a schematic side view showing the same caseless capacitor. Figure 1C is a schematic front view showing the same caseless capacitor. [Figure 2] Figure 2A is a schematic front view illustrating the method for evaluating the heat dissipation effect. Figure 2B is a schematic side view illustrating the method for evaluating the heat dissipation effect. [Figure 3] Figure 3 is a graph showing the relationship between the flattening ratio (B / A) and the temperature rise (△T). [Figure 4] Figure 4 is a graph showing the relationship between the distance between planes (A) and the rise in temperature (△T). [Figure 5] Figure 5 is a graph showing the relationship between total length (X) and temperature rise (△T). [Figure 6] Figure 6 is a graph showing the relationship between electrode thickness (Y) and temperature rise (△T). [Figure 7] Figures 7A and 7B are schematic perspective views showing each step in the manufacturing process of the caseless capacitor described above. [Modes for carrying out the invention]

[0012] 1. First Embodiment (1) Overview As shown in Figures 1A to 1C, the caseless capacitor 1 according to this embodiment comprises a capacitor element 2, a sealing portion 7, and a metal plate 9.

[0013] The capacitor element 2 has a main body 5, a first end face electrode 61, and a second end face electrode 62. The main body 5 extends in a first direction D1, has a first end face 31 on one side in the first direction D1 and a second end face 32 on the other side in the first direction D1, and has a first plane 41 on one side in the second direction D2 and a second plane 42 on the other side in the second direction D2. The first end face electrode 61 is provided on the first end face 31. The second end face electrode 62 is provided on the second end face 32.

[0014] The sealing portion 7 seals the capacitor element 2.

[0015] The metal plate 9 faces the second plane 42 of the capacitor element 2 via an insulating layer 8, and is fixed to the insulating layer 8 and exposed to the outside.

[0016] In this embodiment, the aspect ratio (B / A) of the capacitor element 2 is 2.0 or more and 10.0 or less. The aspect ratio (B / A) is the value of the ratio of the width (B) of the capacitor element 2 along the third direction D3 to the interplanar distance (A) between the first plane 41 and the second plane 42.

[0017] As the aspect ratio (B / A) of the capacitor element 2 increases, the capacitor element 2 tends to be closer to the metal plate 9 as a whole. The metal plate 9 has higher thermal conductivity than the sealing portion 7 and is exposed to the outside.

[0018] Therefore, according to this embodiment, the heat generated in the capacitor element 2 is easily released to the outside. The technical significance of the numerical range of the aspect ratio (B / A) of the capacitor element 2 is clarified in the section of the examples while showing experimental data.

[0019] (2) Details Hereinafter, the case-less capacitor 1 according to this embodiment will be described with reference to the drawings. Each figure is a schematic diagram, and the size of each component in the figure does not necessarily reflect the actual dimensions. Although arrows defining the first direction D1, the second direction D2, and the third direction D3 are shown in the figure, these arrows are shown only for convenience of explanation and do not limit the direction of the case-less capacitor 1 and have no physical entity. The first direction D1, the second direction D2, and the third direction D3 are orthogonal to each other. Further, hereinafter, "front view" means viewing along the first direction D1, "plan view" means viewing along the second direction D2, and "side view" means viewing along the third direction D3.

[0020] As shown in FIGS. 1A to 1C, the case-less capacitor 1 according to this embodiment includes a capacitor element 2, a pair of bus bars 600, a sealing portion 7, and a metal plate 9. Since the case-less capacitor 1 does not have a case literally, it is easy to reduce the weight. The capacitance of the case-less capacitor 1 is preferably as large as possible, for example, 50 μF or more and 300 μF or less.

[0021] <Capacitor element> The capacitor element 2 has a main body 5, a first end face electrode 61, and a second end face electrode 62.

[0022] ≪Main body≫ The main body 5 has a rounded rectangle shape when viewed from the front and a three-dimensional shape that extends in the first direction D1.

[0023] The main body 5 has a first end face 31, a second end face 32, a first flat surface 41, a second flat surface 42, a first curved surface 51, and a second curved surface 52. The first flat surface 41, the second flat surface 42, the first curved surface 51, and the second curved surface 52 are electrically insulating.

[0024] The first end face 31 is located on one side in the first direction D1.

[0025] The second end face 32 is the face opposite the first end face 31 in the first direction D1. That is, the second end face 32 is located on the other side of the first direction D1. The second end face 32 is parallel to the first end face 31. Note that "parallel" includes not only strictly parallel but also parallel that can be considered equivalent to strictly parallel (substantial parallel). "Substantial parallel" means a degree of parallelism that does not impair the effect of this embodiment. The same applies hereafter.

[0026] The first plane 41 is located on one side of the second direction D2. The first plane 41 is connected to the first end face 31 on one side of the first direction D1. The first plane 41 is connected to the second end face 32 on the other side of the first direction D1.

[0027] The second plane 42 is the opposite plane to the first plane in the second direction D2. That is, the second plane 42 is located on the other side of the second direction D2. The second plane 42 is parallel to the first plane 41. The second plane 42 is connected to the first end face 31 on one side of the first direction D1. The second plane 42 is connected to the second end face 32 on the other side of the first direction D1.

[0028] The first curved surface 51 is a curved surface that is convex to one side (right side) of the third direction D3 when viewed from the front. The first curved surface 51 is located on one side of the third direction D3. The first curved surface 51 is connected to the first end surface 31 on one side of the first direction D1. The first curved surface 51 is connected to the second end surface 32 on the other side of the first direction D1. The first curved surface 51 is connected to the first plane 41 on one side of the second direction D2. The first curved surface 51 is connected to the second plane 42 on the other side of the second direction D2.

[0029] The second curved surface 52 is a curved surface that is convex to the other side (left side) of the third direction D3 when viewed from the front. The second curved surface 52 is the surface opposite to the first curved surface 51. That is, the second curved surface 52 is located on the other side of the third direction D3. The second curved surface 52 is connected to the first end surface 31 on one side of the first direction D1. The second curved surface 52 is connected to the second end surface 32 on the other side of the first direction D1. The second curved surface 52 is connected to the first plane 41 on one side of the second direction D2. The second curved surface 52 is connected to the second plane 42 on the other side of the second direction D2.

[0030] ≪First end electrode≫ The first end face electrode 61 is provided on the first end face 31. The first end face electrode 61 can be formed by a metal spraying method. The material of the first end face electrode 61 is not particularly limited, but examples include zinc, copper, and tin.

[0031] ≪Second end electrode≫ The second end face electrode 62 is provided on the second end face 32. The second end face electrode 62 can also be formed by metal spraying. The material of the second end face electrode 62 can be the same as the material of the first end face electrode 61.

[0032] ≪Method for forming capacitor elements≫ The capacitor element 2 is either wound or multilayer. In this embodiment, a wound capacitor element 2 is used. The method for forming the wound capacitor element 2 will be described below.

[0033] First, as shown in Figure 7A, the main body 5 is formed by winding a long metallized film 20. Specifically, two metallized films 20 (a first metallized film 21 and a second metallized film 22) are prepared, and these metallized films 20 are overlapped and wound together. The lengths of the two metallized films 20 in the short direction S are equal.

[0034] The first metallized film 21 has a deposited portion 21a on which metal is deposited and a non-deposited portion 21b on which metal is not deposited. The metal to be deposited is not particularly limited, but examples include aluminum, zinc, and copper. The deposited portion 21a and the non-deposited portion 21b are located on one side of the first dielectric film 210. The deposited portion 21a is located on the portion of the first dielectric film 210 excluding one end (right end) in the short direction S. The non-deposited portion 21b is located on one end (right end) in the short direction S of the first dielectric film 210. The other side of the first dielectric film 210 does not have a deposited portion 21a. The material of the first dielectric film 210 is not particularly limited, but examples include polypropylene (PP), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), and polyethylene naphthalate (PEN). The thickness of the first dielectric film 210 is preferably 1.6 μm or more and 4.0 μm or less, more preferably 1.8 μm or more and 3.4 μm or less, and even more preferably 2.0 μm or more and 3.0 μm or less.

[0035] On the other hand, the second metallized film 22 has a vapor-deposited portion 22a on which metal is deposited and a non-vapor-deposited portion 22b on which metal is not deposited. The metal to be deposited is the same as the metal described above. The vapor-deposited portion 22a and the non-vapor-deposited portion 22b are present on one side of the second dielectric film 220. The vapor-deposited portion 22a is present on the portion of the second dielectric film 220 excluding the other end (left end) in the short direction S. The non-vapor-deposited portion 22b is present on the other end (left end) in the short direction S of the second dielectric film 220. The vapor-deposited portion 22a is not present on the other side of the second dielectric film 220. The material of the second dielectric film 220 is the same as the material of the first dielectric film 210. The thickness of the second dielectric film 220 is the same as the thickness of the first dielectric film 210.

[0036] Then, the other side of the first metallized film 21 and one side of the second metallized film 22 are placed opposite each other and overlapped, and the two metallized films 20 are wound in the longitudinal direction L in this state to obtain a cylindrical wound body 5a (see Figure 7A). By applying pressure to the wound body 5a in a direction perpendicular to the winding axis R, a flat wound body 5b is obtained (see Figure 7B). When viewed along the direction of the winding axis R (first direction D1), the flat wound body 5b has a rounded rectangle shape and a three-dimensional shape that extends in the direction of the winding axis R. In this embodiment, the flat wound body 5b is used as the main body 5.

[0037] At the first end face 31 of the main body 5, the right edge of the second metallized film 22 is exposed. A vapor-deposited portion 22a exists on the right edge of the second metallized film 22. Therefore, the first end face electrode 61 is connected to the vapor-deposited portion 22a of the second metallized film 22.

[0038] On the other hand, the left edge of the first metallized film 21 is exposed at the second end face 32 of the main body 5. A vapor-deposited portion 21a exists on the left edge of the first metallized film 21. Therefore, the second end face electrode 62 is connected to the vapor-deposited portion 21a of the first metallized film 21.

[0039] A pair of busbars 600 (first busbar 601 and second busbar 602) are conductive members extending in a second direction D2. The first busbar 601 is connected to a first end face electrode 61. The second busbar 602 is connected to a second end face electrode 62. The first busbar 601 and the second busbar 602 are arranged side by side in the first direction D1 and parallel to the second direction D2. The material of the pair of busbars 600 is not particularly limited, but examples include copper.

[0040] <Sealing part> The sealing portion 7 seals the capacitor element 2 (see Figures 1A to 1C). In other words, the capacitor element 2 is embedded in the sealing portion 7. To put it another way, the sealing portion 7 is slightly larger than the capacitor element 2 when viewed from the front, top, and side.

[0041] The sealing portion 7 is formed from a cured resin. The resin is not particularly limited, but examples include thermosetting resins such as epoxy resins.

[0042] In this embodiment, the sealing portion 7 is rectangular parallelepiped in shape. Specifically, the sealing portion 7 has a front surface 7a, a rear surface 7b, an upper surface 7c, a lower surface 7d, a right surface 7e, and a left surface 7f.

[0043] The front surface 7a is located on one side in the first direction D1. The front surface 7a is parallel to the first end face electrode 61.

[0044] The rear surface 7b is the surface opposite to the front surface 7a in the first direction D1. That is, the rear surface 7b is located on the other side of the first direction D1. The rear surface 7b is parallel to the front surface 7a.

[0045] The upper surface 7c is located on one side of the second direction D2. The upper surface 7c is parallel to the first plane 41. A pair of busbars 600 protrude from the upper surface 7c.

[0046] The lower surface 7d is the surface opposite to the upper surface 7c in the second direction D2. That is, the lower surface 7d is located on the other side of the second direction D2. The lower surface 7d is parallel to the upper surface 7c. In this embodiment, the lower surface 7d is flush with the second plane 42 of the capacitor element 2.

[0047] The right face 7e is located on one side of the third direction D3.

[0048] The left face 7f is the face opposite the right face 7e in the third direction D3. That is, the left face 7f is on the other side of the third direction D3. The left face 7f is parallel to the right face 7e.

[0049] <Metal plate> The metal plate 9 faces the second plane 42 of the capacitor element 2 via an insulating layer 8. The metal plate 9 also faces the lower surface 7d of the sealing portion 7 via an insulating layer 8. The material of the metal plate 9 is not particularly limited, but examples include aluminum. The thickness of the metal plate 9 is preferably 0.3 mm to 2.5 mm, more preferably 0.5 mm to 2.0 mm, and even more preferably 0.8 mm to 1.5 mm. In plan view, the metal plate 9 has a rectangular shape that is slightly larger than the sealing portion 7. The shape and size of the metal plate 9 in plan view are not particularly limited.

[0050] The metal plate 9 is fixed to the insulating layer 8 and exposed to the outside. The insulating layer 8 is formed of a cured resin. The resin is not particularly limited, but examples include thermosetting resins such as epoxy resin. The thickness of the insulating layer 8 is preferably 0.1 mm or more and 1.0 mm or less, more preferably 0.3 mm or more and 0.6 mm or less, and the insulating layer 8 has a rectangular shape with the same dimensions as the sealing portion 7 when viewed from above.

[0051] <Oblateness> In this embodiment, the flattening ratio (B / A) of the capacitor element 2 is 2.0 or more and 10.0 or less.

[0052] Here, the flattening ratio (B / A) of the capacitor element 2 is the ratio of the width (B) of the capacitor element 2 to the plane-to-plane distance (A). The width (B) of the capacitor element 2 is the length of the capacitor element 2 along the third direction D3 (see Figure 1C). The plane-to-plane distance (A) is the distance between the first plane 41 and the second plane 42 (see Figure 1C).

[0053] As described above, a flatness ratio (B / A) of capacitor element 2 of 2.0 or higher can suppress a decrease in heat dissipation. On the other hand, a flatness ratio (B / A) of capacitor element 2 of 10.0 or lower can suppress a decrease in capacitance of caseless capacitor 1.

[0054] The lower limit of the flatness ratio (B / A) is preferably 2.4 or higher, more preferably 2.8 or higher. On the other hand, the upper limit of the flatness ratio (B / A) is preferably 7.5 or lower, more preferably 5.0 or lower.

[0055] The width (W) of the sealing portion 7 is longer than the width (B) of the capacitor element 2. The width (W) of the sealing portion 7 is the distance between the right surface 7e and the left surface 7f of the sealing portion 7 (see Figure 1C). The preferred width (W) of the sealing portion 7 can vary depending on the width (B) of the capacitor element 2. That is, the width (W) of the sealing portion 7 is preferably (B+1) mm or more and (B+10) mm or less, more preferably (B+2) mm or more and (B+7) mm or less, and even more preferably (B+3) mm or more and (B+5) mm or less.

[0056] <Distance between planes> In this embodiment, the planar distance (A) of the capacitor elements 2 is preferably 10 mm or more and 30 mm or less. A planar distance (A) of 10 mm or more can suppress the decrease in capacitance of the caseless capacitor 1. On the other hand, a planar distance (A) of 30 mm or less can suppress the decrease in heat dissipation.

[0057] The lower limit of the plane-to-plane distance (A) is more preferably 15 mm or more, and even more preferably 20 mm or more. On the other hand, the upper limit of the plane-to-plane distance (A) is more preferably 28 mm or less, and even more preferably 26 mm or less.

[0058] The height (H) of the sealing portion 7 is greater than the plane-to-plane distance (A). The height (H) of the sealing portion 7 is the distance between the upper surface 7c and the lower surface 7d of the sealing portion 7 (see Figure 1C). The preferred height (H) of the sealing portion 7 can vary depending on the plane-to-plane distance (A). Specifically, the height (H) of the sealing portion 7 is preferably (A+0.5) mm or more and (A+10) mm or less, more preferably (A+1.5) mm or more and (A+7) mm or less, and even more preferably (A+2) mm or more and (A+5) mm or less.

[0059] <Total length> In this embodiment, the total length (X) of the capacitor element 2 is preferably 10 mm or more and 30 mm or less.

[0060] Here, the total length (X) of the capacitor element 2 is the length of the capacitor element 2 along the first direction D1 (see Figure 1B). By having a total length (X) of the capacitor element 2 of 10 mm or more, the reduction in capacitance of the caseless capacitor 1 can be suppressed. On the other hand, by having a total length (X) of the capacitor element 2 of 30 mm or less, the decrease in heat dissipation can be suppressed.

[0061] The lower limit of the total length (X) of the capacitor element 2 is more preferably 15 mm or more, and even more preferably 18 mm or more. On the other hand, the upper limit of the total length (X) of the capacitor element 2 is more preferably 28 mm or less, and even more preferably 23 mm or less.

[0062] The total length (TL) of the sealing portion 7 is longer than the total length (X) of the capacitor element 2. The total length (TL) of the sealing portion 7 is the distance between the front surface 7a and the rear surface 7b of the sealing portion 7 (see Figure 1B). The preferred total length (TL) of the sealing portion 7 can vary depending on the total length (X) of the capacitor element 2. That is, the total length (TL) of the sealing portion 7 is preferably (X+1) mm or more and (X+10) mm or less, more preferably (X+2) mm or more and (X+7) mm or less, and even more preferably (X+3) mm or more and (X+6) mm or less.

[0063] <Thickness of the first and second end face electrodes> In this embodiment, the thickness (Y) of the first end face electrode 61 and the second end face electrode 62 (hereinafter also referred to as "electrode thickness (Y)") is preferably 0.5 mm or more and 1.5 mm or less (see Figure 1B). By having an electrode thickness (Y) of 0.5 mm or more, a decrease in heat dissipation can be suppressed. On the other hand, by having an electrode thickness (Y) of 1.5 mm or less, a decrease in solder wettability can be suppressed.

[0064] The lower limit of the electrode thickness (Y) is more preferably 0.7 mm or more, and even more preferably 1.0 mm or more. The thickness of the first end electrode 61 (Y1) and the thickness of the second end electrode 62 (Y2) may be the same or different.

[0065] <Effects and Effects> The caseless capacitor 1 according to this embodiment is charged by applying a voltage between a pair of busbars 600. In particular, by applying an AC voltage between the pair of busbars 600, the caseless capacitor 1 repeatedly charges and discharges. This can cause heat to be generated in the capacitor element 2.

[0066] In order to dissipate the heat mentioned above to the outside, in this embodiment, the flatness ratio (B / A) of the capacitor element 2 is set to 2.0 or more and 10.0 or less. The larger the flatness ratio (B / A) of the capacitor element 2, the closer the capacitor element 2 is to the metal plate 9 overall. Furthermore, the metal plate 9 has higher thermal conductivity than the sealing portion 7 and is exposed to the outside.

[0067] Therefore, according to this embodiment, the heat generated by the capacitor element 2 is easily released to the outside. The technical significance of the numerical range of the flattening ratio (B / A) of the capacitor element 2 is clarified in the Examples section with experimental data (see Figure 3).

[0068] 2. Second Embodiment Next, the caseless capacitor 1 according to the second embodiment will be described with reference to the drawings. In the second embodiment, components similar to those in the first embodiment are denoted by the same reference numerals as in the first embodiment, and detailed descriptions may be omitted.

[0069] <Distance between planes> In this embodiment, the plane distance (A) between the first plane 41 and the second plane 42 is 10 mm or more and 30 mm or less. In this embodiment, the flatness ratio (B / A) of the capacitor element 2 may deviate from the range of 2.0 or more and 10.0 or less.

[0070] A planar distance (A) of 10 mm or more can suppress the reduction in capacitance of the caseless capacitor 1. On the other hand, a planar distance (A) of 30 mm or less can suppress the reduction in heat dissipation.

[0071] The lower limit of the plane-to-plane distance (A) is preferably 15 mm or more, more preferably 20 mm or more. On the other hand, the upper limit of the plane-to-plane distance (A) is preferably 28 mm or less, more preferably 26 mm or less.

[0072] <Effects and Effects> Similar to the first embodiment, the caseless capacitor 1 according to this embodiment also undergoes repeated charging and discharging by applying an AC voltage between a pair of busbars 600. This can cause heat to be generated in the capacitor element 2.

[0073] In order to dissipate the heat mentioned above to the outside, in this embodiment, the plane-to-plane distance (A) of the capacitor elements 2 is set to 10 mm or more and 30 mm or less. The shorter the plane-to-plane distance (A) (i.e., the closer the first plane 41 is to the second plane 42), the closer the capacitor elements 2 as a whole are to the metal plate 9.

[0074] Therefore, according to this embodiment, the heat generated by the capacitor element 2 is easily released to the outside. The technical significance of the numerical range of the plane distance (A) is clarified in the Examples section with experimental data (see Figure 4).

[0075] 3. Third Embodiment Next, the caseless capacitor 1 according to the third embodiment will be described with reference to the drawings. In the third embodiment, components similar to those in the first and second embodiments may be denoted by the same reference numerals as in the first and second embodiments, and detailed descriptions may be omitted.

[0076] <Total length> In this embodiment, the total length (X) of the capacitor element 2 along the first direction D1 is 10 mm or more and 30 mm or less (see Figure 1B). In this embodiment, the flatness ratio (B / A) of the capacitor element 2 may deviate from the range of 2.0 or more and 10.0 or less.

[0077] By having a total length (X) of capacitor element 2 of 10 mm or more, the reduction in capacitance of caseless capacitor 1 can be suppressed. On the other hand, by having a total length (X) of capacitor element 2 of 30 mm or less, the decrease in heat dissipation can be suppressed.

[0078] The lower limit of the total length (X) of the capacitor element 2 is preferably 15 mm or more, more preferably 18 mm or more. The upper limit of the total length (X) of the capacitor element 2 is preferably 28 mm or less, more preferably 23 mm or less.

[0079] <Effects and Effects> Similar to the first embodiment, the caseless capacitor 1 according to this embodiment also undergoes repeated charging and discharging by applying an AC voltage between a pair of busbars 600. This can cause heat to be generated in the capacitor element 2.

[0080] In order to dissipate the heat mentioned above, in this embodiment, the total length (X) of the capacitor element 2 is set to 10 mm or more and 30 mm or less. If the total length (X) is too long, the heat dissipation effect may saturate (see Figure 5), but if the total length (X) is 30 mm or less, the longer the total length (X), the greater the area in close proximity between the capacitor element 2 and the metal plate 9.

[0081] Therefore, according to this embodiment, the heat generated by the capacitor element 2 is easily released to the outside. The technical significance of the numerical range of the total length (X) is clarified in the Examples section with experimental data (see Figure 5).

[0082] 4. Fourth Embodiment Next, the caseless capacitor 1 according to the fourth embodiment will be described with reference to the drawings. In the fourth embodiment, components similar to those in the first to third embodiments are denoted by the same reference numerals as in the first to third embodiments, and detailed descriptions may be omitted.

[0083] <Thickness of the first and second end face electrodes> The thickness (Y) of the first end electrode 61 and the second end electrode 62 is 0.5 mm or more and 1.5 mm or less (see Figure 1B). In this embodiment, the flatness ratio (B / A) of the capacitor element 2 may deviate from the range of 2.0 to 10.0.

[0084] By having an electrode thickness (Y) of 0.5 mm or more, a decrease in heat dissipation can be suppressed. On the other hand, by having an electrode thickness (Y) of 1.5 mm or less, a decrease in solder wettability can be suppressed.

[0085] The lower limit of the electrode thickness (Y) is preferably 0.7 mm or more, more preferably 1.0 mm or more. The thickness of the first end electrode 61 (Y1) and the thickness of the second end electrode 62 (Y2) may be the same or different.

[0086] <Effects and Effects> Similar to the first embodiment, the caseless capacitor 1 according to this embodiment also undergoes repeated charging and discharging by applying an AC voltage between a pair of busbars 600. This can cause heat to be generated in the capacitor element 2.

[0087] In order to dissipate the heat mentioned above, in this embodiment, the thickness (Y) of the first end electrode 61 and the second end electrode 62 is set to 0.5 mm or more and 1.5 mm or less. If the electrode thickness (Y) is too thick, the solder wettability may decrease, but if the electrode thickness (Y) is 1.5 mm or less, the thicker the electrode thickness (Y), the greater the area in close proximity between the first end electrode 61 and the second end electrode 62 and the metal plate 9. Similar to the metal plate 9, the first end electrode 61 and the second end electrode 62 have higher thermal conductivity than the sealing portion 7, so heat can easily escape from the first end electrode 61 and the second end electrode 62 to the metal plate 9.

[0088] Therefore, according to this embodiment, the heat generated by the capacitor element 2 is easily released to the outside. The technical significance of the numerical range of the electrode thickness (Y) is clarified in the Examples section with experimental data (see Figure 6). [Examples]

[0089] The present disclosure will be specifically described below with reference to examples.

[0090] 1. Sample To evaluate the heat dissipation effect, 20 caseless capacitors 1 (samples 1-22) were manufactured by changing the dimensions of the capacitor element 2 (wound type) as shown in Figures 1A-1C (see Table 1). The capacitance of each sample is 115 μF. The sealing portion 7 of each sample is formed from cured epoxy resin. The width (W) of the sealing portion 7 is (B+5) mm, the height (H) of the sealing portion 7 is (A+5) mm, and the total length (TL) of the sealing portion 7 is (X+6) mm.

[0091] The first dielectric film 210 of each sample is a 2.0 μm thick polypropylene (PP) film. The second dielectric film 220 is the same as the first dielectric film 210.

[0092] In each sample, the first metallized film 21 has a vapor-deposited portion 21a with a thickness of 20 nm formed by the deposition of aluminum. The vapor-deposited portion 22a of the second metallized film 22 is the same as the vapor-deposited portion 21a of the first metallized film 21.

[0093] The metal plate 9 in each sample is a 1mm thick aluminum plate.

[0094] The insulating layer 8 of each sample is formed from a cured epoxy resin adhesive. The thickness of the insulating layer 8 is 0.3 mm.

[0095] The material of the first end electrode 61 and the second end electrode 62 of each sample is zinc.

[0096] The total length (X), width (B), plane-to-plane distance (A), electrode thickness (Y), and flattening ratio (B / A) of the capacitor element 2 for each sample are shown in Table 1. The electrode thickness (Y) is the thickness of the first end electrode 61 and the second end electrode 62, respectively. In other words, the thickness of the first end electrode 61 (Y1) and the thickness of the second end electrode 62 (Y2) are the same.

[0097] [Table 1]

[0098] 2. Evaluation Method In an atmosphere of 85°C, the caseless capacitor 1 was placed on a cooling plate 90 at 65°C with the metal plate 9 facing downwards, as shown in Figures 2A and 2B. In this way, the metal plate 9 and the cooling plate 90 were in contact. After a sufficient amount of time had elapsed in this state and equilibrium was reached, the temperature of the caseless capacitor 1 was measured and this temperature was taken as the reference temperature (temperature before energization). The temperature measurement point of the caseless capacitor 1 was the center of the first plane 41 of the capacitor element 2. The temperature was measured using a thermocouple.

[0099] Next, an AC current of 100A with a frequency of 10kHz was passed between the pair of busbars 600. After a sufficient amount of time had elapsed and equilibrium was reached, the temperature of the caseless capacitor 1 was measured, and this temperature was defined as the temperature after energization.

[0100] Then, the temperature rise (△T) relative to the reference temperature was determined from the difference between the temperature after power was applied and the temperature before power was applied. The temperature rise (△T) for each sample is shown in Table 1. By analyzing the experimental data in Table 1, the following insights regarding the heat dissipation effect were obtained.

[0101] 3.Results (1) Oblateness (B / A) Table 2 was created by extracting some samples from Table 1.

[0102] [Table 2]

[0103] Figure 3 is a graph created using the experimental data from Table 2. Specifically, by plotting the flattening ratio (B / A) on the horizontal axis and the temperature rise (△T) on the vertical axis, the graph shown in Figure 3 was obtained. In Figure 3, Y(0.5) represents the curve when the electrode thickness (Y) is 0.5 mm, Y(1.0) represents the curve when the electrode thickness (Y) is 1.0 mm, and Y(2.0) represents the curve when the electrode thickness (Y) is 2.0 mm.

[0104] From Figure 3, it can be seen that if the flatness ratio (B / A) of capacitor element 2 is 2.0 or greater, the temperature rise (△T) can be kept below 25°C. Furthermore, in terms of heat dissipation, it appears that there is no problem even if the flatness ratio (B / A) of capacitor element 2 is greater than 5.0.

[0105] (2) Distance between planes (A) Table 3 was created by extracting some samples from Table 1.

[0106] [Table 3]

[0107] Figure 4 is a graph created using the experimental data from Table 3. Specifically, by plotting the distance between planes (A) on the horizontal axis and the temperature rise (△T) on the vertical axis, the experimental data from Table 3 was obtained as shown in Figure 4.

[0108] From Figure 4, it can be seen that the temperature rise (△T) can be kept below 20°C if the plane-to-plane distance (A) of the capacitor elements 2 is 30 mm or less. Furthermore, in terms of heat dissipation, it appears that there is no problem even if the plane-to-plane distance (A) of the capacitor elements 2 is shorter than 20 mm.

[0109] Furthermore, the results for sample 21 in Table 1 confirmed that if the plane-to-plane distance (A) is between 10 mm and 30 mm, the temperature rise (△T) can be kept below 25°C even if the flatness ratio (B / A) of capacitor element 2 deviates from the range of 2.0 to 10.0.

[0110] (3) Total length (X) Table 4 was created by extracting some samples from Table 1.

[0111] [Table 4]

[0112] Figure 5 is a graph created using the experimental data from Table 4. Specifically, by plotting the experimental data from Table 4 with total length (X) on the horizontal axis and temperature rise (△T) on the vertical axis, the graph shown in Figure 5 was obtained.

[0113] Figure 5 shows that when the total length (X) of capacitor element 2 exceeds 30 mm, the temperature rise (△T) remains almost constant. Also, Figure 5 suggests that if the total length (X) of capacitor element 2 is 30 mm or less, the temperature rise (△T) can be kept below 22°C. Furthermore, in terms of heat dissipation, it appears that there is no problem even if the total length (X) of capacitor element 2 is less than 18 mm.

[0114] Furthermore, the results for sample 22 in Table 1 confirmed that if the total length (X) of capacitor element 2 is between 10 mm and 30 mm, the temperature rise (△T) can be kept below 25°C even if the flatness ratio (B / A) of capacitor element 2 deviates from the range of 2.0 to 10.0.

[0115] (4) Electrode thickness (Y) Table 5 was created by extracting some samples from Table 1.

[0116] [Table 5]

[0117] Figure 6 is a bar graph created using the experimental data from Table 5. From Figure 6, it can be seen that, in terms of heat dissipation effect alone, a thicker electrode (Y) is preferable.

[0118] Furthermore, the results for sample 22 in Table 1 confirmed that if the electrode thickness (Y) is between 0.5 mm and 1.5 mm, the temperature rise (△T) can be kept below 25°C even if the flatness ratio (B / A) of capacitor element 2 deviates from the range of 2.0 to 10.0.

[0119] Table 6, on the other hand, was prepared by adding sample 23 to samples 1, 2, and 4 in Table 5. The electrode thickness (Y) of sample 23 is 1.5 mm.

[0120] The solder wettability of samples 1, 2, 4, and 21 was evaluated by contact angle. The contact angle was measured using the "Automatic Contact Angle Meter DMe-201" manufactured by Kyowa Interface Science Co., Ltd. The evaluation criteria are as follows:

[0121] A: Contact angle less than 30° B: Contact angle between 30° and less than 45° C: Contact angle exceeds 45°.

[0122] [Table 6]

[0123] Table 6 shows that, in terms of solder wettability, an electrode thickness (Y) thinner than 2.0 mm is advantageous. [Explanation of symbols]

[0124] 1 Caseless Capacitor 2 Capacitor elements 31 First end surface 32 Second end face 41 1st plane 42 Second plane 5 Main body 61 1st end electrode 62 2nd end electrode 7. Sealing section 8. Insulating layer 9 metal plate A Distance between planes B Width D1 1st direction D2 2nd direction D3 Third direction L total length T thickness

Claims

1. A capacitor element having a main body that extends in a first direction, has a first end face on one side in the first direction and a second end face on the other side in the first direction, and has a first plane on one side in a second direction perpendicular to the first direction and a second plane on the other side in the second direction, a first end face electrode provided on the first end face, and a second end face electrode provided on the second end face, A sealing portion that seals the capacitor element, The capacitor element comprises a metal plate that faces the second plane of the capacitor element via an insulating layer and is fixed to the insulating layer and exposed to the outside, The sealing portion is entirely exposed to the outside, except for the surface facing the metal plate. The flattening ratio (B / A), which is the ratio of the width (B) of the capacitor element along a third direction perpendicular to the first and second directions to the plane-to-plane distance (A) between the first plane and the second plane, is 2.0 or more and 10.0 or less. Caseless capacitor.

2. The thickness of the first end face electrode and the second end face electrode is 0.5 mm or more and 1.5 mm or less. A caseless capacitor according to claim 1.

3. The plane distance (A) is 10 mm or more and 30 mm or less. A caseless capacitor according to claim 1 or 2.

4. The total length of the capacitor element along the first direction is 10 mm or more and 30 mm or less. A caseless capacitor according to any one of claims 1 to 3.

5. A capacitor element having a main body that extends in a first direction, has a first end face on one side in the first direction and a second end face on the other side in the first direction, and has a first plane on one side in a second direction perpendicular to the first direction and a second plane on the other side in the second direction, a first end face electrode provided on the first end face, and a second end face electrode provided on the second end face, A sealing portion that seals the capacitor element, The capacitor element comprises a metal plate that faces the second plane of the capacitor element via an insulating layer and is fixed to the insulating layer and exposed to the outside, The sealing portion is entirely exposed to the outside, except for the surface facing the metal plate. The thickness of the first end electrode and the second end electrode is 0.5 mm or more and 1.5 mm or less. Caseless capacitor.

6. The plane distance between the first plane and the second plane is 10 mm or more and 30 mm or less. The caseless capacitor according to claim 5.

7. The total length of the capacitor element along the first direction is 10 mm or more and 30 mm or less. A caseless capacitor according to claim 5 or 6.

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