Chip-type electrolytic capacitors

Abstract

This invention provides a chip-type electrolytic capacitor that forms a sufficient resin layer between the capacitor body and the base plate. [Solution] A chip-type electrolytic capacitor comprising a bottomed cylindrical outer case in which a capacitor element is housed, a sealing body that seals the opening thereof, a capacitor body having lead terminals connected to the capacitor element and penetrating the sealing body, and a seat plate 3 positioned opposite the sealing body to hold the capacitor body, wherein the seat plate has a seat plate body portion 31 and a seat plate peripheral wall portion 32 formed around it, a pair of insertion holes 33 through which lead terminals are inserted are formed in the seat plate body portion, a plurality of radial grooves 341 extending radially from the center of the inner bottom surface toward the seat plate peripheral wall portion are formed on the inner bottom surface 34 of the seat plate body portion opposite the sealing body, resin is filled between the seat plate and the capacitor body, and the resin filled in each of the plurality of radial grooves can flow through the center of the inner bottom surface, thereby filling the space between the seat plate and the capacitor body with resin more uniformly.

Description

Technical Field

[0001] The present invention relates to a chip-shaped electrolytic capacitor used by being surface-mounted on a substrate.

Background Art

[0002] A chip-shaped electrolytic capacitor used by being surface-mounted on a substrate is composed of a capacitor body and a seating plate. The seating plate is provided with insertion holes through which lead terminals led out from the capacitor body are inserted, and the lead terminals are arranged on the substrate mounting surface side outside the seating plate through the insertion holes. When mounting the chip-shaped electrolytic capacitor on the substrate, the tip-side portion of the lead terminal is electrically connected to a predetermined portion of the substrate by soldering.

[0003] Improvements in vibration resistance and resistance in a high-temperature environment are required for the above-described chip-shaped electrolytic capacitor. In the chip-shaped electrolytic capacitor described in Patent Document 1, a liquid resin is injected between a sealing member attached to the opening of the exterior case of the capacitor body and the seating plate (expressed as a pedestal in Patent Document 1) to form a resin layer, thereby enhancing the sealing property of the capacitor and improving the heat resistance of the capacitor.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Patent Document 1 describes that a liquid resin is injected into the gap between the capacitor body and the seating plate and a part inside the insertion hole portion, and after the resin is filled, the resin solidifies to form a resin layer. However, depending on the state of the gap between the capacitor body and the seating plate, it is difficult to uniformly fill the resin into the gap, and there is a possibility that a sufficient resin layer cannot be formed between the capacitor body and the seating plate.

[0006] The present invention aims to provide a chip-type electrolytic capacitor that can form a sufficient resin layer between the capacitor body and the base plate. [Means for solving the problem]

[0007] The chip electrolytic capacitor disclosed herein comprises a capacitor element, a bottomed cylindrical outer case in which the capacitor element is housed, a sealing body that seals the opening of the outer case, a capacitor body having lead terminals connected to the capacitor element and penetrating the sealing body, and a seat plate positioned opposite the sealing body and holding the capacitor body, wherein the seat plate has a seat plate body portion and a seat plate peripheral wall portion formed around the seat plate body portion, a pair of insertion holes through which the lead terminals are inserted are formed in the seat plate body portion, a plurality of radial grooves extending radially from the center of the inner bottom surface toward the seat plate peripheral wall portion are formed on the inner bottom surface of the seat plate body portion opposite the sealing body, and resin is filled between the seat plate and the capacitor body.

[0008] With this configuration, the resin is filled into multiple radial grooves formed on the inner bottom surface of the base plate body, ensuring uniform resin coverage between the base plate and the capacitor body, thereby forming a sufficient resin layer between them. As a result, the anchoring effect across the entire inner bottom surface of the base plate body is enhanced, increasing the adhesive strength between the capacitor body and the base plate, and improving the vibration resistance of the chip-type electrolytic capacitor.

[0009] Furthermore, the radial grooves may have a shape in which the width gradually widens from the center of the inner bottom surface toward the peripheral wall of the seat plate.

[0010] With this configuration, the resin is filled more and more uniformly into the radial grooves on the inner bottom surface of the seat plate body, thereby forming a sufficient resin layer between the seat plate and the condenser body.

[0011] Furthermore, the plurality of radial grooves may be in communication with each other at the central part of the inner bottom surface.

[0012] With this configuration, the resin filled in each of the multiple radial grooves can flow through the center of the inner bottom surface, allowing for more uniform resin filling between the base plate and the condenser body.

[0013] Furthermore, a central groove may be formed in the portion between the pair of insertion holes in the central part of the inner bottom surface, extending linearly in the direction connecting the pair of insertion holes.

[0014] With this configuration, the resin is filled into the central groove connecting the pair of through holes, which further increases the fluidity of the resin and allows for more uniform filling of the resin between the base plate and the condenser body.

[0015] Furthermore, an outer peripheral through-hole may be formed in the portion of the inner bottom surface closest to the seat plate peripheral wall portion, which connects to the gap between the seat plate main body and the capacitor body.

[0016] With this configuration, resin is injected into the inner bottom surface of the seat plate body, and after bonding the condenser body and the seat plate, it is possible to determine whether the outer circumference of the seat plate body is sufficiently filled with resin.

[0017] Furthermore, a central through-hole may be formed in the center of the inner bottom surface, connecting to the gap between the base plate body and the capacitor body.

[0018] With this configuration, resin is injected into the inner bottom surface of the seat plate body, and after bonding the condenser body and the seat plate, it is possible to determine whether the center of the seat plate body is sufficiently filled with resin.

[0019] Furthermore, the area around the pair of insertion holes may have a convex shape that protrudes toward the sealing body.

[0020] According to this configuration, it is possible to suppress the resin injected between the seat plate and the capacitor body from overflowing from the insertion holes and adhering to the lead terminals.

Advantages of the Invention

[0021] According to the present invention, it is possible to provide a chip-shaped electrolytic capacitor capable of forming a sufficient resin layer between the capacitor body and the seat plate.

Brief Description of the Drawings

[0022] [Figure 1] It is a schematic configuration diagram showing the appearance and internal structure of a chip-shaped electrolytic capacitor according to an embodiment of the present invention. [Figure 2] It is a top view of the seat plate of FIG. 1. [Figure 3] It is a top perspective view of the seat plate of FIG. 1. [Figure 4] It is a cross-sectional view taken along line A-A of FIG. 3. [Figure 5] It is a cross-sectional view taken along line B-B of FIG. 3. [Figure 6] It is an explanatory diagram showing an example of a method of applying resin to the seat plate main body portion. [Figure 7] It is a bottom view of the seat plate of FIG. 1. [Figure 8] It is a bottom perspective view of the seat plate of FIG. 1.

Modes for Carrying Out the Invention

[0023] Hereinafter, a chip-shaped electrolytic capacitor 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 8. As shown in FIG. 1, the chip-shaped electrolytic capacitor 1 according to the present embodiment includes a capacitor body 2 and a seat plate 3 that holds the capacitor body 2.

[0024] The capacitor body 2 includes a capacitor element 20, a bottomed cylindrical exterior case 21 in which the capacitor element 20 is housed, a sealing body 22 that seals the open end of the exterior case 21, and a pair of lead terminals 23 that are connected to the capacitor element 20 and penetrate the sealing body 22.

[0025] The capacitor element 20 is formed by winding an anode foil and a cathode foil, each having an oxide film formed on a valve-acting metal foil such as aluminum foil, with a separator in between. The anode foil and cathode foil are connected to a pair of lead terminals 23. The separator holds the electrolyte. The electrolyte may be an electrolyte solution only, a solid electrolyte mainly composed of a conductive polymer resin only, or both a solid electrolyte and an electrolyte solution.

[0026] The outer casing 21 is made of, for example, aluminum. In this embodiment, the outer casing 21 is a bottomed cylindrical shape, but it may also be a bottomed elliptical cylinder shape. The sealing body 22 is made of an elastic material such as rubber. When manufacturing the capacitor body 2, the capacitor element 20 is housed inside the outer casing 21, the sealing body 22 is placed inside the open end of the outer casing 21, and then the outer casing 21 is sealed by the sealing body 22 by crimping the area of ​​the outer casing 21 facing the sealing body 22.

[0027] The base plate 3 is positioned opposite the sealing body 22. As shown in Figures 2-5, the base plate 3 consists of an insulating base plate body 31 and a base plate peripheral wall 32. The base plate body 31 is the bottom plate on which the capacitor body 2 is placed, and the base plate peripheral wall 32 consists of four side walls surrounding the outer surface of the capacitor body 2. The base plate body 31 and the base plate peripheral wall 32 are made of a heat-resistant synthetic resin.

[0028] As shown in Figures 2-5, multiple radial grooves 341 are formed on the inner bottom surface 34 of the seat plate body 31, extending radially from the center of the inner bottom surface 34 toward the seat plate peripheral wall 32. The radial grooves 341 have a shape in which the width gradually widens from the center of the inner bottom surface 34 toward the seat plate peripheral wall 32.

[0029] The liquid resin 35 may be applied to the base plate body 31 in a shape resembling the Japanese character "no," as shown in Figure 6. When the liquid resin 35 is applied to the inner bottom surface 34 of the base plate body 31, the resin 35 fills the radial grooves 341, causing the resin 31 to spread uniformly from the center of the inner bottom surface 34 toward the base plate peripheral wall 32, and the resin 31 to uniformly fill the space between the base plate 3 and the capacitor body 2. As a result, a sufficient resin layer can be formed between the base plate 3 and the capacitor body 2. After the resin 35 is applied to the inner bottom surface 34 of the base plate body 31, the base plate body 31 is bonded to the sealing body 22 of the capacitor body 2. The filling of the space between the base plate 3 and the capacitor body 2 increases the adhesive strength between the capacitor body 2 and the base plate 3, improving the vibration resistance of the chip-type electrolytic capacitor 1.

[0030] As shown in Figures 2-5, the multiple radial grooves 341 provided on the inner bottom surface 34 of the seat plate body 31 are in communication with each other in the central part of the inner bottom surface 34. When liquid resin 35 is applied to the inner bottom surface 34 of the seat plate body 31, the resin 35 filled in each of the multiple radial grooves 341 can flow through the central part of the inner bottom surface 34, thereby allowing the resin 35 to be filled more uniformly between the seat plate 3 and the condenser body 2.

[0031] As shown in Figures 2-5, a central groove 342 is formed in the central part of the inner bottom surface 34 of the seat plate body 31, between the pair of insertion holes 33, extending linearly in the direction connecting the pair of insertion holes 33. When the liquid resin 35 is applied to the inner bottom surface 34 of the seat plate body 31, the liquid resin 35 fills the central groove 342 connecting the pair of insertion holes 33, further increasing the fluidity of the resin 35 and allowing the resin to be filled more uniformly between the seat plate 3 and the condenser body 2.

[0032] As shown in Figures 2-5, four outer peripheral through-holes 37a are formed in the inner bottom surface 34 of the seat plate body 31, near the seat plate peripheral wall 32, connecting to the gap between the seat plate body 31 and the capacitor body 2. By providing these outer peripheral through-holes 37a, it is possible to determine whether the resin 35 has been sufficiently filled into the outer periphery of the seat plate 3 after injecting the resin 35 into the inner bottom surface 34 of the seat plate body 31 and bonding the capacitor body 2 and the seat plate 3.

[0033] As shown in Figures 2-5, a central through-hole 37b is formed in the center of the inner bottom surface 34 of the seat plate body 31, which connects to the gap between the seat plate body 31 and the capacitor body 2. By providing this central through-hole 37b, it is possible to determine whether the resin 35 has been sufficiently filled in the center of the seat plate 3 after injecting the resin 35 into the inner bottom surface 34 of the seat plate body 31 and bonding the capacitor body 2 and the seat plate 3.

[0034] As shown in Figures 2-5, the area around the pair of insertion holes 33, 331, is convex, protruding toward the sealing body 22. By making the area around the pair of insertion holes 33, 331, convex, it is possible to prevent the resin 35 injected between the base plate 3 and the capacitor body 2 from overflowing from the insertion holes 33 and adhering to the lead terminals 23.

[0035] The outer bottom surface 36 of the base plate body 31 is located on the opposite side from the sealing body 22. As shown in Figures 7 and 8, the outer bottom surface 36 of the base plate body 31 is the surface that forms the bottom surface of the chip-type electrolytic capacitor 1. As shown in Figure 7, in a plan view of the chip-type electrolytic capacitor 1 from the outer bottom surface 36 side, the base plate body 31 is approximately square, but it may be circular, elliptical, or a polygon other than approximately square.

[0036] As shown in Figures 7 and 8, the base plate body 31 has a pair of insertion holes 33 through which a pair of lead terminals 23 are inserted. The outer bottom surface 36 of the base plate body 31 has a pair of lead terminal storage grooves 38 that extend from the pair of insertion holes 33 in opposite directions, with their tips reaching the two sides of the base plate body 31, respectively. As shown in Figure 1, the tip portions of the pair of lead terminals 23 pulled out from the pair of insertion holes 33 are bent and stored in the pair of lead terminal storage grooves 38. The tips of the pair of lead terminals 23 protrude from the sides of the base plate body 31. When mounting the chip-type electrolytic capacitor 1 onto a substrate (not shown), the tip portions of the pair of lead terminals 23 are soldered to the substrate.

[0037] (Example test) A test was conducted to determine whether the liquid resin applied to the inner bottom surface of the seat board body was uniformly coated from the center to the outer edge. Specifically, in the 18mm diameter base plate, radial grooves were formed on the base plate body to a depth of 0.25mm, with each groove having an angle of 15°. In the center of the base plate body, a central groove with a depth of 0.25mm was formed in a straight line along the direction connecting the lead terminal insertion holes. In addition, φ0.1mm through-holes were formed in four locations on the outer circumference and one location in the center of the base plate body. As shown in Figure 6, 0.136g of liquid resin (one-component thermosetting epoxy resin (manufactured by ThreeBond Co., Ltd.)) was applied to the circular inner bottom surface (circumference 9mm) of the base plate body using a quantitative dispenser, in a circular motion. After bonding the capacitor body and the base plate, the resin coating was heat-cured at 100°C for 1 hour. Visual inspection of the resin coating confirmed that the resin had filled the through-holes.

[0038] Although embodiments of the present invention have been described above, these are merely illustrative examples and do not particularly limit the present invention. Specific configurations and other aspects can be modified as appropriate. Furthermore, the actions and effects described in the embodiments of the invention are merely a list of the most preferred actions and effects resulting from the present invention, and the actions and effects according to the present invention are not limited to those described in the embodiments.

[0039] For example, the above embodiment can be modified as follows:

[0040] The radial grooves 341 do not necessarily have to be shaped in a way that gradually widens from the center of the inner bottom surface 34 of the seat plate body 31 toward the seat plate peripheral wall 32. The radial grooves 341 may also be shaped in a way that extends with the same width from the center of the inner bottom surface 34 of the seat plate body 31 toward the seat plate peripheral wall 32. [Explanation of symbols]

[0041] 1. Chip-type electrolytic capacitor 2 Capacitor body 3 Seat board 20 Capacitor elements 21 Outer case 22 Sealing body 23 Lead terminals 31 Seat board main body 32 Seat plate peripheral wall 33 Through hole 331 Hole circumference 34 Inner bottom surface 341 Radial grooves 342 Central groove 35 Resin 36 Outer bottom surface 37 Throughpores 37a Peripheral through hole 37b Center hole 38 Lead terminal storage groove

Claims

1. A capacitor body having a capacitor element, a bottomed cylindrical outer case in which the capacitor element is housed, a sealing body that seals the opening of the outer case, and lead terminals connected to the capacitor element and passing through the sealing body, A base plate positioned opposite the sealing body and holding the capacitor body, A chip-type electrolytic capacitor equipped with, The aforementioned seat plate has a seat plate body and a seat plate peripheral wall formed around the seat plate body, The main body of the seat plate has a pair of insertion holes through which the lead terminals are inserted. Multiple radial grooves are formed on the inner bottom surface of the seat plate body facing the sealing body, extending radially from the center of the inner bottom surface toward the seat plate peripheral wall. A resin is filled between the base plate and the capacitor body. Chip-type electrolytic capacitor.

2. In the chip-type electrolytic capacitor of claim 1, The radial grooves have a shape in which the width gradually widens from the center of the inner bottom surface toward the peripheral wall of the seat plate. Chip-type electrolytic capacitor.

3. In the chip-type electrolytic capacitor according to claim 1 or 2, The plurality of radial grooves are in communication with each other at the central part of the inner bottom surface. Chip-type electrolytic capacitor.

4. In the chip-type electrolytic capacitor according to claim 1 or 2, In the central part of the inner bottom surface, between the pair of insertion holes, a central groove is formed that extends linearly along the direction connecting the pair of insertion holes. Chip-type electrolytic capacitor.

5. In the chip-type electrolytic capacitor according to claim 1 or 2, An outer peripheral through-hole is formed in the portion of the inner bottom surface closest to the peripheral wall portion of the seat plate, which connects to the gap between the seat plate body and the capacitor body. Chip-type electrolytic capacitor.

6. In the chip-type electrolytic capacitor according to claim 1 or 2, A central through-hole is formed in the center of the inner bottom surface, which connects to the gap between the base plate body and the capacitor body. Chip-type electrolytic capacitor.

7. In the chip-type electrolytic capacitor according to claim 1 or 2, The area around the pair of insertion holes has a convex shape that protrudes toward the sealing body side. Chip-type electrolytic capacitor.

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