JP2011249708A - Solid electrolytic capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solid electrolytic capacitor which can enhance the bond strength and the peel strength between a lead terminal and an anode part or the like, and can reduce the resistance value thereof, while keeping the strength of the lead terminal.SOLUTION: A solid electrolytic capacitor has a capacitor element whose anode part and cathode part are connected to each respective lead terminal. The connection part of the lead terminal, connected to the anode part and/or the cathode part, has a flat portion having approximately the same thickness as the other portion of the lead terminal except the connection part; and step portions projecting from the flat portion and having a greater thickness. The step portions are formed at each respective position facing each other in the width direction of the lead terminal.

Description

  The present invention relates to a solid electrolytic capacitor such as a multilayer solid electrolytic capacitor.

  In a solid electrolytic capacitor, a flat lead terminal whose base material is made of 42 alloy, copper, or the like is usually used, and an anode portion or the like of a capacitor element is connected on the lead terminal. As the anode portion, for example, a tantalum wire is used in a tantalum solid electrolytic capacitor, and an anode aluminum foil is used in an aluminum laminated solid electrolytic capacitor.

  Conventionally, methods such as welding or using a conductive adhesive have been used to connect the lead terminal and the anode part, etc., in order to maintain the mechanical strength of the connection part and reduce its resistance value, Various ideas were made.

As a method for connecting such a lead terminal and an anode part, for example, there is a method of using a lead terminal bent into a Chiritori shape and bending and pressing an aluminum laminated element after installation (see, for example, Patent Document 1).
Further, there is a method in which a metal that can be easily welded is provided in advance on the aluminum portion of the anode portion of the capacitor element, and welding is performed (for example, see Patent Document 2).
Further, there is a method of welding by providing unevenness on the lead terminal (see, for example, Patent Document 3).
Furthermore, there is a method in which the frame tip is formed wide so that the frame tip extends in both directions along the frame lateral direction, and the portions on both sides thereof are bent into the front and back sides (see, for example, Patent Document 4).

JP 2003-45753 A JP 2006-54327 A JP 2005-93591 A JP-A-11-135367

However, in the connection methods described in Patent Documents 1 and 2, the connection between the lead terminal and the anode part is performed by welding two opposing planes (the surface of the lead terminal and the anode part) or by using a conductive adhesive or the like. Therefore, there is a problem that it is difficult to obtain a sufficient bonding strength and it is difficult to obtain a sufficient peel resistance accompanying the application of external stress.
Moreover, in patent document 3, since the unevenness | corrugation was directly provided in the flat lead terminal, there existed a problem that the intensity | strength of lead terminal itself fell. Further, it is difficult to form unevenness having a sufficient depth, it is difficult to obtain a sufficient anchor effect, and there is a problem that the bonding strength is not sufficient.
Also in Patent Document 4, there is a problem that it is difficult to obtain a sufficient anchor effect due to its structure, and it is difficult to obtain a sufficient bonding strength.
In addition, a method has been studied in which bending is applied to the tip of the lead terminal to ensure a thickness that does not break even if the welding strength is sufficiently increased when the inner element is welded to the tantalum wire. Therefore, it has been difficult to ensure sufficient bonding strength and peel resistance.

  An object of the present invention is to provide a solid electrolytic capacitor capable of increasing the bonding strength and peel resistance between a lead terminal and an anode portion and the like and reducing the resistance value while ensuring the strength of the lead terminal. It is.

In order to solve the above-described problems, the present invention employs the following configuration.
(1) A solid electrolytic capacitor in which a lead terminal is connected to each of an anode part and a cathode part of a capacitor element,
The connecting portion of the lead terminal with the anode portion and / or the cathode portion is provided with a flat portion having substantially the same thickness as the portion other than the connecting portion of the lead terminal, and protruding from the flat portion. There is a step portion with an increased thickness dimension, and the step portion is formed at each position facing the width direction of the lead terminal.

According to the configuration of (1), the connecting portion of the lead terminal with the anode portion and / or the cathode portion includes the flat portion and the step portion, and the step portion is opposed to the lead terminal in the width direction. It is formed at the position. Here, as shown in FIG. 1, the connection portion refers to a location where the capacitor element and the lead terminal are connected. Therefore, the lead terminal and the welding material, the conductive adhesive, etc. are sufficiently engaged by the unevenness formed by the step portions formed at the respective positions facing the width direction of the lead terminal, thereby providing an excellent anchor effect. Can be demonstrated. As a result, it is possible to increase the bonding strength and peel resistance between the lead terminal and the anode portion and reduce the resistance value.
Further, the flat portion has substantially the same thickness as the portion other than the connection portion of the lead terminal, and the stepped portion protrudes from the flat portion and increases in the thickness direction. Therefore, as described above, the strength of the lead terminal can be ensured while improving the bonding strength and peel strength between the lead terminal and the anode portion and reducing the resistance value.

The present invention can further employ the following configurations.
(2) The solid electrolytic capacitor of (1),
A plurality of convex portions whose thickness dimension is increased by the step portion are provided.

  Conventionally, when welding an aluminum laminated element to a lead terminal, due to a difference in melting point between materials, aluminum easily melts and spreads to the periphery and solidifies (hereinafter referred to as sputtering), When this spatter becomes large, there is a problem that it is exposed to the outside when there is no allowance for product dimensions. In particular, in the case of a bottom electrode type capacitor, the exposure of spatter has become a more prominent problem.

According to the configuration of the above (2), a plurality of convex portions whose thickness dimension is increased by the stepped portion are provided, and among the stepped portions that the plurality of convex portions have, the region sandwiched between the facing stepped portions, Since a welding material (aluminum or the like) melted at the time of welding or a conductive adhesive or the like can be accommodated, exposure of the welding material or the conductive adhesive or the like (for example, exposure of spatter) can be prevented.
In addition, when the welding material or conductive adhesive enters the region sandwiched between the opposing stepped portions, the lead terminal and the welding material or conductive adhesive etc. are sufficiently engaged, thereby providing an excellent anchoring effect. Can demonstrate. As a result, it is possible to increase the bonding strength and peel resistance between the lead terminal and the anode portion and reduce the resistance value.

The present invention can further employ the following configurations.
(3) The solid electrolytic capacitor of (1) or (2),
The step portion is formed to form an acute angle with respect to the flat portion.

  According to the configuration of (3), since the step portion forms an acute angle with respect to the flat portion, the engagement between the lead terminal and the welding material, conductive adhesive, or the like becomes stronger. Therefore, the anchor effect can be further strengthened, and as a result, the bonding strength between the lead terminal and the anode part and the peel strength can be further increased and the resistance value can be reduced.

The present invention can further employ the following configurations.
(4) The solid electrolytic capacitor according to any one of (1) to (3),
The step portion is also formed along the width direction at the tip of the lead terminal.

  According to the configuration of (4), since the step portion is formed along the width direction at the tip of the lead terminal, the contact area between the lead terminal and the welding material, conductive adhesive, or the like is reduced. As a result, it is possible to increase the bonding strength and peel resistance between the lead terminal and the anode part, and to reduce the resistance value. Moreover, exposure of a welding material, a conductive adhesive, etc. can also be prevented.

The present invention can further employ the following configurations.
(5) The solid electrolytic capacitor according to any one of (1) to (4),
The convex portion is a folded portion formed by folding the tip of the lead terminal into a bent shape,
The step portion is formed by a side wall surface of the folded portion.

  According to the configuration of (5) above, the stepped portion has a height approximately equal to the thickness dimension of the lead terminal (thickness dimension of the portion other than the connecting portion of the lead terminal). In addition, the contact area with the conductive adhesive or the like can be increased. As a result, the bonding strength and peel strength between the lead terminal and the anode portion can be increased, and the resistance value can be reduced. Further, since the step portion can be formed high, it is possible to secure a storage space for the welding material, conductive adhesive, and the like, and as a result, it is possible to prevent the welding material, conductive adhesive, etc. from being exposed. . Furthermore, since the step portion can be easily formed, the manufacturing cost can be suppressed.

The present invention can further employ the following configurations.
(6) The solid electrolytic capacitor of (5),
The folded portion is formed with a slit or hole extending from the tip of the lead terminal,
The step portion is formed by a side wall surface of the folded portion facing the slit portion or the hole portion.

  According to the configuration of the above (6), a welding material, a conductive adhesive, or the like enters the slit portion or the hole portion, and thereby an excellent anchor effect can be exhibited. As a result, it is possible to increase the bonding strength and peel resistance between the lead terminal and the anode portion and reduce the resistance value.

The present invention can further employ the following configurations.
(7) The solid electrolytic capacitor of (5) or (6),
A gap is formed between the flat portion and the inner surface of the folded portion.

  According to the structure of said (7), a welding material, a conductive adhesive, etc. enter | penetrate into a clearance gap, and, thereby, the outstanding anchor effect can be exhibited. As a result, it is possible to increase the bonding strength and peel resistance between the lead terminal and the anode portion and reduce the resistance value.

  According to the solid electrolytic capacitor of the present invention, it is possible to increase the bonding strength and peel resistance between the lead terminal and the anode portion and the like and to reduce the resistance value while securing the strength of the lead terminal.

1 is a perspective view schematically showing an example of a multilayer solid electrolytic capacitor according to the present invention. (A) is a perspective view which shows the connection part of the anode lead terminal shown in FIG. 1, (b) is the sectional view on the AA line of (a), (c) is a connection of an anode lead terminal It is sectional drawing which shows the other example of a part. (A)-(d) is a perspective view which shows the modification of the connection part of an anode lead terminal, respectively. (A), (b) is sectional drawing which shows typically the modification of a multilayer solid electrolytic capacitor, respectively. (A), (b) is a perspective view which shows the modification of the connection part of an anode lead terminal, respectively.

FIG. 1 is a perspective view schematically showing an example of a multilayer solid electrolytic capacitor 10 according to the present invention.
The multilayer solid electrolytic capacitor 10 is a bottom electrode type, includes a multilayer capacitor element 11, an anode lead terminal 20 is connected to the anode portion 13 of the multilayer capacitor element 11, and a cathode lead terminal 19 is connected to the cathode portion 15. It is configured by being connected and sealed with a mold resin. In the figure, 16 indicates a mold part.

  The material and shape of the anode lead terminal 20 and the cathode lead terminal 19 are not particularly limited. For example, a flat lead terminal whose base material is made of 42 alloy, copper, or the like can be used. Can be used. In the present invention, slits 24a and 24b (FIG. 2) are formed at the tip of the anode lead terminal 20, and the first step portions 22a to 22d (FIG. 2), which will be described later, are formed by a simple method by bending them into a bent shape. Can be formed.

  The multilayer capacitor element 11 is configured by laminating a plurality of capacitor element plates 12. Capacitor element plate 12 uses valve action metal foil as a base material, anode part 13 located on one side of the surface of valve action metal foil, cathode part 15 formed on the other side, and anode part 13 and cathode part 15 The resist part 14 formed between the two is provided. In the anode part 13, the valve action metal foil is exposed. The cathode portion 15 is formed by sequentially laminating an oxide film layer, a solid electrolyte layer, and a cathode lead layer on the surface of the valve action metal foil. The resist portion 14 insulates the anode portion 13 and the cathode portion 15 from each other. As such a multilayer capacitor element 11, a conventionally known one can be employed. In the plurality of capacitor element plates 12, each anode part 13 is laminated on one end side (right end side in the figure) of the multilayer capacitor element 11, and each cathode part 15 is laminated on the other end side (left side in the figure). Thereby, the multilayer capacitor element 11 has a two-terminal structure.

  The anode portion 13 and the cathode portion 15 of the lowermost capacitor element plate 12 are the anode portion 13 and the cathode portion 15 of the multilayer capacitor element 11, respectively, and the anode lead 13 and the cathode portion 15 of the multilayer capacitor element 11 respectively have anode leads. Terminal 20 and cathode lead terminal 19 are connected.

  The tip of the anode lead terminal 20 is bent back toward the upper side (the multilayer capacitor element 11 side), thereby forming a convex portion (folded portion, corresponding to the step portion of the present invention) 23 (FIG. 2). ing. The upper surface of the convex part 23 and the lower surface of the anode part 13 of the multilayer capacitor element 11 are joined by welding. In the figure, reference numeral 27 denotes a connecting portion of the anode lead terminal 20. The connection part 27 is a part connected to the anode part 13 of the multilayer capacitor element 11. In the anode lead terminal 20, the portion excluding the convex portion corresponds to a flat portion.

Next, the anode lead terminal 20 will be described.
2A is a perspective view showing a connecting portion of the anode lead terminal 20 shown in FIG. 1, and FIG. 2B is a cross-sectional view taken along line AA in FIG.

  As shown in FIG. 2A, the anode lead terminal 20 has a plurality (three) of convex portions (folded portions) 23a to 23c. The convex portions 23 a to 23 c are arranged along the width direction of the anode lead terminal 20, and slit portions 24 a and 24 b extending in the longitudinal direction of the anode lead terminal 20 are formed between the convex portions 23 a to 23 c. Yes. As a result, in plan view, the area of the lower part of the anode lead terminal 20 is larger than the area where the upper part and the lower part of the anode lead terminal 20 overlap. The bottom surfaces of the slit portions 24 a and 24 b are located on the same plane as the flat surface 21. The convex portions 23 a and 23 c on both sides reach both ends in the width direction of the anode lead terminal 20.

The first step portion 22a of the convex portion 23a is composed of a side wall surface of the convex portion 23a facing the slit portion 24a. The first step portion 22b of the convex portion 23b is formed of a side wall surface of the convex portion 23b facing the slit portion 24a. The first step portions 22 a and 22 b are formed at respective positions facing the anode lead terminal 20 in the width direction.
The first step portion 22c of the convex portion 23b is formed of a side wall surface of the convex portion 23b facing the slit portion 24b. The first step portion 22d of the convex portion 23c is formed of a side wall surface of the convex portion 23c facing the slit portion 24b. The first step portions 22 c and 22 d are formed at respective positions facing the anode lead terminal 20 in the width direction.

The second step portions 25a and 25b are formed along the width direction of the anode lead terminal 20 at the tip of the anode lead terminal 20, and face the slit portions 24a and 24b, respectively.
The third step portions 26 a, 26 b, and 26 c are formed of the side wall surface on the rear end side of the anode lead terminal 20 among the side wall surfaces of the convex portion 23.

As shown in FIG. 2B, slit portions 24a and 24b are formed between the convex portions 23a to 23c of the anode lead terminal 20, respectively. The first step portions 22a and 22b and the second step portion 25a face the slit portion 24a, and the first step portions 22c and 22d and the second step portion 25b are the slit portion 24b. Facing.
The first step portions 22a to 22d and the bottom surfaces (flat surfaces 21) of the slit portions 24a and 24b are orthogonal to each other, and the second step portions 25a and 25b and the bottom surfaces (flat surfaces) of the slit portions 24a and 24b are flat. Is perpendicular to the surface 21).

  According to the multilayer solid electrolytic capacitor 10 described above, the first stepped portions 22a to 22d are formed at the respective positions facing the width direction of the anode lead terminal 20, and therefore the first stepped portions 22a to 22d. The anode lead terminal 20 meshes with the welding material, the conductive adhesive, and the like due to the unevenness constituted by the above, and thereby an excellent anchor effect can be exhibited. As a result, the bonding strength and peel strength between the anode lead terminal 20 and the anode portion 13 can be increased and the resistance value can be reduced.

Moreover, since the several convex part 23a-23c is provided, a welding material, a conductive adhesive, etc. can be accommodated in slit part 24a, 24b pinched | interposed into 1st step part 22a-22d which opposes. . Accordingly, it is possible to prevent the welding material, the conductive adhesive, and the like from being exposed.
In addition, since the second step portions 25a and 25b are formed along the width direction at the tip of the anode lead terminal 20, it is possible to increase the bonding strength and the peel strength and reduce the resistance value. In addition, exposure of the welding material, conductive adhesive, etc. (for example, leakage of the welding material, conductive adhesive, etc. toward the bottom surface side of the multilayer solid electrolytic capacitor 10) can be prevented.

  Further, since the protrusions 23a to 23c are formed by bending the tip of the anode lead terminal 20 into a bent shape, the first step portions 22a to 22d are secured with a large thickness dimension, and one level of metal is formed. Slits 24a and 24b having a depth that cannot be secured by a flat plate can be formed. Accordingly, it is possible to prevent the welding material, the conductive adhesive, and the like from being exposed. Furthermore, since the first step portions 22a to 22d can be formed by a simple method of forming and bending a metal flat plate, the manufacturing cost can be reduced.

Moreover, since the convex parts 23a and 23c have reached the both ends of the width direction of the anode lead terminal 20, exposure of a welding material, a conductive adhesive, etc. can be prevented more reliably.
As shown in FIG. 1, in the multilayer solid electrolytic capacitor 10, the cathode portion 15 is thicker than the anode portion 13 of the multilayer capacitor element 11. Here, according to the present embodiment, the tip of the anode lead terminal 20 is bent back to form the convex portion 23, thereby compensating for the height difference and supporting the multilayer capacitor element 11 with a good balance. be able to.

  Although FIG. 2B illustrates the case where the first step portions 22a to 22d and the bottom surfaces (flat surfaces 21) of the slit portions 24a and 24b are orthogonal to each other, the present invention is limited to this example. Is not to be done.

FIG. 2C is a cross-sectional view showing another example of the connecting portion of the anode lead terminal. In FIG. 2 (c), the same components as those in FIG. 2 (b) are denoted by the same reference numerals.
In the anode lead terminal 20 ′ shown in FIG. 2C, the first step portions 22a ′ to 22d ′ and the bottom surfaces (flat surfaces 21) of the slit portions 24a and 24b form an acute angle. The slit portions 24 a and 24 b have a tapered shape in which the width gradually increases from the upper side to the lower side in the thickness direction of the anode lead terminal 20. Thereby, the meshing between the anode lead terminal 20 and the welding material, the conductive adhesive or the like becomes stronger, and for example, aluminum that has melted and spread in the portion is easily bitten. Therefore, the anchor effect can be further strengthened, and as a result, the bonding strength and the peel resistance between the anode lead terminal 20 ′ and the anode portion 13 can be further increased and the resistance value can be reduced.

  Regarding the formation of the first step portions 22 a ′ to 22 d ′ that form an acute angle with the flat surface 21, first, a slit portion is formed at the tip of a metal flat plate that becomes the anode lead terminal 20. The slit portion formed here has a tapered shape that gradually becomes narrower from the upper side to the lower side in the thickness direction of the metal flat plate. Thereafter, the tip of the metal flat plate is bent upward in a bent shape, thereby forming convex portions (folded portions) 23a to 23c shown in FIG. In the convex portions 23 a to 23 c, the first step portions 22 a ′ to 22 d ′ and the bottom surfaces of the slit portions 24 a and 24 b form an acute angle, and the slit portions 24 a and 24 b are on the lower side in the thickness direction of the anode lead terminal 20. It has a shape that becomes wider as it goes.

  Although not shown, in the present invention, a gap is formed between the surface of the flat portion 21 of the anode lead terminal 20 and the inner surface of the convex portion (folded portion) 23 shown in FIG. May be. By forming the gap in this way, the welding material, the conductive adhesive, etc. reach the gap through the slit portion, so that the anode lead terminal 20 is strongly engaged with the welding material, the conductive adhesive, etc. be able to. In addition, in FIG.2 (b) and FIG.2 (c), said clearance gap is abbreviate | omitted.

  Next, regarding the shape of the stepped portion (convex portion), the embodiment shown in FIGS. 1 and 2 has described the case where the three convex portions 23a to 23c and the two slit portions 24a and 24b are formed. The present invention is not limited to this example. Examples of the shape of the stepped portion (convex portion) in the present invention include the shapes shown in FIGS.

3A to 3D are perspective views showing modifications of the connecting portion of the anode lead terminal.
The anode lead terminal 30 shown in FIG. 3A includes a convex portion 33 at the center portion on the tip side. The convex portion 33 is formed by folding the tip of the anode lead terminal 30 in a bent shape, and has the same height as the thickness of the flat portion 31. The first step portions 32 a and 32 b of the convex portion 33 are opposed to each other with the convex portion 33 interposed therebetween. Further, the third step portion 36 of the convex portion 33 is formed of a side wall surface on the rear end side of the anode lead terminal 30 among the side wall surfaces of the convex portion 33.

According to the anode lead terminal 30, the first stepped portions 32 a and 32 b are formed at the respective positions facing the anode lead terminal 30 in the width direction, and thus are constituted by the first stepped portions 32 a and 32 b. Due to the unevenness, the anode lead terminal 30 meshes with the welding material, the conductive adhesive, and the like, and thereby an excellent anchor effect can be exhibited.
Thus, in the present invention, as shown in FIG. 1 and FIG. 2, the side wall surfaces of the convex portions constituting the stepped portion do not necessarily face each other, as shown in FIG. The side wall surfaces of the convex portions constituting the stepped portion may face each other.

  The anode lead terminal 40 shown in FIG. 3B includes convex portions 43 a and 43 b on both ends in the width direction of the anode lead terminal 40. The convex portions 43 a and 43 b are formed by folding the tip of the anode lead terminal 40 into a bent shape, and have the same height as the thickness of the flat portion 41. The first step portions 42 a and 42 b of the convex portions 43 a and 43 b face each other through the slit portion 44. The slit portion 44 has a wider width (opening area) than the slit portions 24a and 24b shown in FIG. The second step 45 is formed along the width direction of the anode lead terminal 40 at the tip of the anode lead terminal 40 and faces the slit 44.

  As described above, in the present invention, convex portions are formed on both ends in the width direction of the anode lead terminal, and a wide slit is provided between the convex portions, so that a space for accommodating a welding material, a conductive adhesive, or the like is provided. Since it can ensure widely, exposure of a welding material, a conductive adhesive, etc. can be prevented.

  The anode lead terminal 50 shown in FIG. 3C includes one convex portion 53. The convex portion 53 includes a hollow hole portion 54 along the width direction of the anode lead terminal 50, and the hole portion 54 does not reach the rear end of the convex portion 53 in the length direction of the anode lead terminal 50. The convex portion 53 reaches both end sides in the width direction of the anode lead terminal 50. The convex portion 53 is formed by folding the tip of the anode lead terminal 50 into a bent shape, and has the same height as the thickness of the flat portion 51. The first step portions 52 a and 52 b of the convex portion 53 are opposed to the anode lead terminal 50 in the width direction through the hole portion 54. The second stepped portion 55 is formed along the width direction of the anode lead terminal 50 at the tip of the anode lead terminal 50, and the fourth stepped portion 57 is connected to the second stepped portion via the hole portion 54. It consists of the side wall surface of the convex part 53 which faces the part 55. FIG. That is, the second step portion 55 and the fourth step portion 57 are opposed to each other in the length direction of the anode lead terminal 50 through the hole portion 54. The third stepped portion 56 includes a side wall surface on the rear end side of the anode lead terminal 50 in the side wall surface of the convex portion 53.

  The anode lead terminal 50 is formed along the width direction of the anode lead terminal 50 at the first step portions 52 a and 52 b provided at positions facing the width direction of the anode lead terminal 50 and the tip of the anode lead terminal 50. In addition to the formed second step portion 55, a fourth step portion 57 is formed at a position facing the second step portion 55.

  In the present invention, as shown in FIG. 3 (c), by forming a hole portion that has a stepped portion and does not reach the outer edge of the anode lead terminal, the bonding strength and the peel strength are increased, and While reducing the resistance value, it is possible to more reliably prevent the welding material, the conductive adhesive, and the like from being exposed.

  The anode lead terminal 60 shown in FIG. 3D includes one convex portion 63. The convex part 63 is formed with a semicircular cutout (slit part) 64 in plan view. The first step portions 62a and 62b are side wall surfaces at positions facing the width direction of the anode lead terminal 60 in the side wall surfaces of the convex portion 63, and the second step portion 65 is on the convex portion 63 side. It consists of a side wall surface facing the rear end side of the anode lead terminal 60 of the wall surface.

  In FIG. 3 (d), the first step portions 62 a and 62 b facing each other are smoothly continued in an arc shape via the second step portion 65. Even in such an embodiment, the first stepped portions 62a and 62b facing each other form irregularities along the width direction of the anode lead terminal 60, so that the bonding strength and the peel strength can be increased, and While reducing the resistance value, it is possible to more reliably prevent the welding material, the conductive adhesive, and the like from being exposed.

  In this specification, the first step portion is a step portion formed at each position facing the width direction of the lead terminal, and the second step portion has a width at the tip of the lead terminal. It is the level | step-difference part formed along the direction. A 3rd level | step-difference part is a level | step difference part which consists of a side wall surface located in the rear-end side of a lead terminal among the side wall surfaces of a convex part. The fourth step portion is a step portion formed so as to face the second step portion.

  Regarding the convex portion (stepped portion), the embodiment shown in FIG. 1 has described the case where the convex portion 23 is formed only on the anode lead terminal 20, but the present invention is not limited to this example. For example, the embodiment shown in FIGS. 4A and 4B can be employed.

  4A and 4B are cross-sectional views schematically showing modifications of the multilayer solid electrolytic capacitor, respectively. 4A and 4B, the same reference numerals as those in FIG. 1 are given to the same components as those in FIG.

  In the multilayer solid electrolytic capacitor 10 shown in FIG. 4A, not only the anode lead terminal 20 includes a convex portion (folded portion) 23, but also the cathode lead terminal 19 includes a convex portion (folded portion) 29. In this respect, the multilayer solid electrolytic capacitor 10 shown in FIG. 4A is different from the multilayer solid electrolytic capacitor 10 shown in FIG. 1, but is otherwise the same as the multilayer solid electrolytic capacitor 10 shown in FIG. is there. At this time, the step 29 and the slit of the aspect as shown in FIG. 2 and FIG. 3 are also provided on the convex portion 29 of the cathode lead terminal 19 so that the cathode lead terminal 19 meshes with the conductive adhesive, Needless to say, exposure of the conductive adhesive or the like can be more reliably prevented while increasing the bonding strength and the peel resistance and reducing the resistance value.

  In the multilayer solid electrolytic capacitor 10 shown in FIG. 4B, the convex portion (folded portion) 29 of the cathode lead terminal 19 is smaller than that in the multilayer solid electrolytic capacitor 10 shown in FIG. In the present invention, the area of the convex portion (folded portion) is not particularly limited, and may be as large as shown in FIG. 4B, and conversely, substantially the entire surface of the anode portion or the cathode portion. The size may be such that it can come into contact.

  Further, regarding the shape of the convex portion, in the example shown in FIG. 2 and FIG. 3, the case where the outer edge of the upper convex portion is located immediately above the outer edge of the lower flat portion or inside the outer edge of the flat portion is described. However, in the present invention, the outer edge of the convex portion may be located outside the outer edge of the flat portion, for example, as shown in FIGS.

FIGS. 5A and 5B are perspective views showing modifications of the connecting portion of the anode lead terminal, respectively.
An anode lead terminal 70 shown in FIG. 5A includes protrusions 73 a and 73 b on both ends in the width direction of the anode lead terminal 70. The convex portions 73 a and 73 b are formed by folding the tip of the anode lead terminal 70 into a bent shape, and have the same height as the thickness of the flat portion 71. In the width direction of the anode lead terminal 70, the outer edges of the protrusions 73 a and 73 b are located outside the outer edge of the flat part 71. The first step portions 72 a and 72 b of the convex portions 73 a and 73 b are opposed to each other through the slit portion 74. The second step 75 is formed along the width direction of the anode lead terminal 70 at the tip of the anode lead terminal 70 and faces the slit 74.

  According to the anode lead terminal 70 shown in FIG. 5A, since the convex portions 73a and 73b protrude outward from the flat portion 71, a capacitor element (not shown) wider than the flat portion 71 is obtained. Can also be joined.

  The anode lead terminal 80 shown in FIG. 5B includes convex portions 83 a and 83 b on both ends in the width direction of the anode lead terminal 80. The protrusions 83a and 83b are formed by bending the tip of the anode lead terminal 80 in a bent shape and further bending the outer edges of the protrusions 83a and 83b upward. The outer edges of the convex portions 83 a and 83 b are located outside the outer edge of the flat portion 81. The first step portions 82a and 82b of the convex portions 83a and 83b are opposed to each other through the slit portion 84. The second step portion 85 is formed along the width direction of the anode lead terminal 80 at the tip of the anode lead terminal 80 and faces the slit portion 84.

  According to the anode lead terminal 80 shown in FIG. 5 (b), the multilayer capacitor element (not shown) and the anode lead terminal 80 can be connected not only from below by the convex portions 83 a and 83 b bent upward. Since bonding can be performed from the side, the bonding strength and the peel strength can be further increased and the resistance value can be reduced. Moreover, exposure of a welding material, a conductive adhesive, etc. can also be prevented by the convex parts 83a and 83b bent upward.

The embodiments according to the present invention have been described above, but the present invention is not limited to these embodiments.
In the above-described embodiments, the case where the anode lead terminal is folded in two stages and the case where the cathode lead terminal and the anode lead terminal are folded in two stages have been described. However, the present invention is not limited to this example. Absent. For example, only the cathode lead terminal may be folded. Further, the number of times the lead terminal is folded (the number of steps of the convex portion) is not particularly limited.
However, in the case where the anode lead terminal and the cathode lead terminal have a convex portion, the thickness dimension of the convex portion of the anode lead terminal is the same as that of the cathode lead terminal in order to compensate for the difference in thickness between the cathode portion and the anode portion of the multilayer capacitor element. It is preferable that the thickness is larger than the thickness of the convex portion.

  In the embodiment described above, the multilayer solid electrolytic capacitor has been described as an example, but the present invention is not limited to the multilayer solid electrolytic capacitor. Further, the thickness of the lead terminal is not necessarily the same between the lower stage and the upper end. Furthermore, in the present invention, the convex portion does not necessarily need to be formed by folding the tip of the lead terminal. For example, the step portion may be formed by forming a groove, a notch or the like at the tip of the lead terminal having a large thickness at the tip.

  In the above-described embodiment, the convex portion (folded portion) is formed by folding the tip of the lead terminal once into a bent shape and forming the tip of the lead terminal in two stages. The lead terminal may be folded back more than once, and the tip of the lead terminal may have three or more steps.

Furthermore, in the above-described embodiment, the multilayer solid electrolytic capacitor has a two-terminal shape including one anode lead terminal and one cathode lead terminal, but the solid electrolytic capacitor according to the present invention is shown in this example. For example, the same effect can be obtained even with a multilayer solid electrolytic capacitor having a three-terminal structure. As a multilayer solid electrolytic capacitor having a three-terminal structure, for example, an anode part is provided at both ends of a capacitor element, a cathode part is provided between two anode parts, and anode lead terminals are provided at both ends of the capacitor element. A multilayer solid electrolytic capacitor having a three-terminal structure in which a cathode lead terminal is arranged between the anode lead terminals can be given.
The capacitor element in a multilayer solid electrolytic capacitor having a three-terminal structure is configured by laminating a plurality of capacitor element plates. The plurality of capacitor element plates have their anode portions facing each other centering on the cathode portion. It is laminated so that. In other words, the plurality of capacitor element plates are laminated such that the cathode portion is located at the center portion of the capacitor element and the anode portions are alternately located at each end portion of the capacitor element. The anode portion of the lowermost capacitor element plate and the anode portion of the upper capacitor element plate, and the cathode portion of the lowermost capacitor element plate are two anode portions and one cathode portion of the capacitor element, respectively.

  Note that the present invention is not limited to the above-described example, and it is possible to make design changes as appropriate within a range that satisfies the configuration of the present invention.

DESCRIPTION OF SYMBOLS 10 Multilayer type solid electrolytic capacitor 11 Multilayer capacitor element 12 Capacitor element board 13 Anode part 14 Resist part 15 Cathode part 16 Mold part 19 Cathode lead terminal 20 Anode lead terminal 21 Flat surface 22a-22d 1st level | step difference part (folding part of a folding part) Side wall surface)
23a-23c Convex part (folded part)
24a, 24b Slit portion 25a, 25b Second step portion (side wall surface of folded portion)
26a-26c 3rd level | step difference part (side wall surface of a folding | turning part)
27 connections

Claims (8)

A solid electrolytic capacitor in which a lead terminal is connected to each of an anode part and a cathode part of a capacitor element,
The connecting portion of the lead terminal with the anode portion and / or the cathode portion is provided with a flat portion having substantially the same thickness as the portion other than the connecting portion of the lead terminal, and protrudes from the flat portion. The solid electrolytic capacitor is characterized in that a stepped portion having a large thickness dimension is formed, and the stepped portion is formed at each position facing the width direction of the lead terminal. The solid electrolytic capacitor according to claim 1,
A solid electrolytic capacitor, wherein a plurality of convex portions whose thickness dimension is increased by the step portion are provided. The solid electrolytic capacitor according to claim 1 or 2,
The step portion is formed so as to form an acute angle with respect to the flat portion. The solid electrolytic capacitor according to any one of claims 1 to 3,
The step portion is formed along the width direction at the tip of the lead terminal. The solid electrolytic capacitor according to any one of claims 1 to 4,
The convex portion is a folded portion formed by folding the tip of the lead terminal into a bent shape,
The step portion is formed by a side wall surface of the folded portion. The solid electrolytic capacitor according to claim 5,
The folded portion is formed with a slit or hole extending from the tip of the lead terminal,
The stepped portion is formed by a side wall surface of the folded portion facing the slit portion or the hole portion. A solid electrolytic capacitor according to claim 5 or 6,
A solid electrolytic capacitor, wherein a gap is formed between the flat portion and an inner surface of the folded portion. A solid electrolytic capacitor according to any one of claims 1 to 7,
The anode section is provided at both ends of the capacitor element, and the cathode section is provided between the two anode sections.

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