JPH04167417A - Solid electrolytic capacitor - Google Patents

Abstract

PURPOSE:To provide a thin solid electrolytic capacitor of a high capacitance which is manufactured at a low fault rate by a method wherein both an anode lead terminal and a cathode lead terminal are formed at the same end part, a plurality of tongue pieces for attaching the anode leads of individual capacitor elements are formed on the anode lead terminal in different height positions and the cathode lead terminal is attached to a cathode layer of a capacitor element multilayered body. CONSTITUTION:For a capacitor element multilayered body 12, individual capacitor elements 1a to 1c are stacked via conductive adhesive materials 11. An anode lead terminal 13 and a cathode lead terminal 14 are formed at end parts of the same lead frame 15; tongue pieces 13a to 13c are formed at an end part of the anode lead terminal 13 in different height positions. Individual anode leads 3 are so arranged as to be shifted to form steps in such a way that the leads 3 are not overlapped in the same place when the capacitor elements 1a to 1c are stacked inside one projection space; also the tongue pieces 13a to 13c are arranged in a stair shape. The cathode lead terminal 14 is provided, at its end part, with a cathode-layer support face 14a which has been bent so as to support the capacitor element 1a at the lowermost stage.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a solid electrolytic capacitor, and more specifically, to a solid electrolytic capacitor that uses a plurality of flat capacitor elements each having a flat electrode foil. be.

[Conventional technology]

A capacitor element using a plate-shaped electrode foil can be made thinner than a foil-wound type or a metal powder sintered body. FIG. 6 shows an example of the flat capacitor element 1.

That is, this capacitor element 1 includes an electrode foil 2 made of a flat aluminum foil. An anode lead 3 is attached to a predetermined portion of this electrode foil 2 . In this case, the anode lead 3 includes a flat plate portion 3a and a rod-shaped lead leg 3b connected to one end thereof, and the flat plate portion 3a is attached to the electrode foil 2 by caulking, ultrasonic welding, or the like.

A solid electrolyte 4 made of a conductive polymer (for example, polypyrrole) is formed around the electrode foil 2, and a cathode layer 7 made of a carbon layer 5 and a silver layer 6 is formed thereon. Although not shown, a cathode lead is attached to this cathode layer 7 with a conductive adhesive such as adhesive silver.

Here, to explain the method of forming the solid electrolyte 3 using polypyrrole as an example, first, a pyrrole monomer is uniformly applied to the electrode foil 2 to which the anode electrode 3 is attached, and then a predetermined oxidizing agent is added to the electrode foil 2. The oxidized polymer film is formed by immersion in a solution.Second, electrolytic polymerization is performed using the oxidized polymer film as an anode in an electrolytic solution containing a supporting electrolyte and a pyrrole monomer, and a polypyrrole film is formed on the oxidized polymer film. Form an electrolytically polymerized membrane.

[Problem to be solved by the invention]

By using such a capacitor element 1, a thin solid electrolytic capacitor can be obtained, but since it is composed of a single foil and its area is limited, a very high capacitance cannot be obtained.

Therefore, after forming a solid electrolyte (polypyrrole) on foil the size of several sheets, we folded it into a zigzag shape, for example.
If an attempt is made to obtain a capacitor element that is flat as a whole, the problem is that cracks and peeling occur in the polypyrrole when the capacitor element is bent, resulting in frequent leakage current failures.

[Means to solve the problem]

The present invention was made in view of the above-mentioned conventional circumstances, and its structural features are that an anode lead is attached to a predetermined part of a flat electrode foil, and a solid electrolyte made of a conductive polymer is placed around the electrode foil. In a solid electrolytic capacitor having a plurality of flat capacitor elements formed by forming a cathode layer made of carbon, silver, etc. on the same solid electrolyte, the plurality of flat capacitor elements are connected to each other between the cathode layers. It has a capacitor element laminate in which a capacitor element is laminated with a conductive adhesive interposed therebetween, and a lead frame in which an anode lead terminal and a cathode lead terminal for external extraction are formed at the same end. The anode lead mounting plate corresponding to the anode lead of each of the capacitor elements is formed at different height positions, and the cathode lead terminal is attached to the cathode layer of the capacitor element laminate using a conductive adhesive. At the same time, each anode lead of the capacitor element is welded to the corresponding tongue piece, and the capacitor element laminate is housed in an exterior case, and the anode lead terminal and the anode lead terminal separated from the lead frame are The cathode lead terminal is bent along the side surface of the exterior case. In this case, it is preferable that the plurality of tongue pieces are arranged in a stepped manner at the end of the anode lead terminal.

[For production]

According to the above configuration, a plurality of capacitor elements can be efficiently electrically connected in parallel without applying mechanical stress to the solid electrolyte made of a conductive polymer. Furthermore, by arranging a plurality of tongues in a step-like manner at the end of the anode lead terminal, each capacitor element can be stacked within the projection space of one of the tongues, thereby achieving a thin profile and its width. A high-capacity solid electrolytic capacitor can be obtained in which the size is reduced to the size of one capacitor element.

〔Example〕

11th! I has three flat capacitor elements 1a to 1c.
An example using . Note that in this figure and in Figure 2 explained below, each of the capacitor elements 1a to 1c is shown with the anode lead attached to the electrode foil for convenience of drawing, but in reality, the anode lead is attached to the electrode foil. Similar to the capacitor element 1 shown in FIG. 6, a homogeneous electrolyte 4 made of, for example, polypyrrole is formed around an electrode foil 2, and a cathode layer 7 made of a carbon layer 5 and a silver layer is further formed thereon. I would like to be understood as someone who is

In this example, each capacitor element 1a-1c is
With each lead leg 3b pulled out in the same direction,
As shown in FIG. 2, the capacitor element laminate 12 is laminated with a conductive adhesive (for example, adhesive silver) 11 interposed therebetween.
and the cathode lead terminal 14.

In this case, the anode lead terminal 13 and the cathode lead terminal 1
4 are both formed at the ends of the same lead frame 15. At the end of the anode lead terminal 13, three tongue pieces 13a to 13c are formed at different height positions. That is, each tongue piece 13a-13c is a capacitor element 18-
They are arranged at slightly larger intervals in relation to each thickness of the IC. In addition, each anode lead 3 is
When the capacitor elements 18 to 1c are stacked within the projection space of one of them, their arrangement is shifted in a stepwise manner so that their anode leads 3 do not overlap at the same location, and accordingly, the tongue pieces 13a ~13c are also arranged in a stepwise manner. The cathode lead terminal 14 has at its end a cathode layer support surface 14a that is bent into a substantially L-shape so as to support the lowermost capacitor element 1a.

In assembling, first, the first capacitor element 1a is placed so as to straddle the cathode layer support surface 14a of the cathode lead frame 14 and the lowermost tongue piece 13a of the anode lead frame 13. In this case, a conductive adhesive 11 is applied to the cathode layer support surface 14a in advance, and the cathode layer 7 (see FIG. 6) of the capacitor element 1a is fixed to the cathode layer support surface 14a with the adhesive silver 11. . In addition, capacitor element 1
First, the lead leg 3b of the anode lead 3 of a is welded to the tongue piece 13a, and then the conductive adhesive 11 is dropped onto the cathode layer 7 of the capacitor element 1a using a nozzle (not shown) or the like.
A second capacitor element 1b is added to the same capacitor element laminate.
Place them one on top of the other.

As a result, each cathode layer 7 of capacitor elements 1a and 1b,
7 is fixed in an electrically connected state.

In addition, the anode lead 3 of the capacitor element 1b is glued to the lead leg 3.
b is welded to the middle tongue piece 13b.

Similarly, the capacitor element 1b is connected via the conductive adhesive 11.
Place the third capacitor element IC on top, and connect the lead leg 3b of the anode lead 3 to the uppermost tongue piece 13.
Weld to c.

After forming the capacitor element laminate 12 in this manner, as shown in FIG. Store inside. Same exterior case 17
is made of a flat bottomed rectangular cylinder made of resin that matches the size of the capacitor element stack 12, and the inside thereof is finally filled with a sealing resin 18 such as epoxy resin.

Thereafter, as shown in FIG. 4, the anode lead terminal 13 and cathode lead terminal 14 are separated from the lead frame 15, and each of the lead terminals 13 and 14 is packaged as shown in FIG. By bending the case 17 along the side surface, a chip-type solid electrolytic capacitor is obtained as a final product.

In the above embodiment, the tongues 13a to 13c are arranged in a stepwise manner along a predetermined inclination angle from the right side to the left side of the anode lead terminal 13 illustrated in FIG. Although the upper tongue pieces do not get in the way when stacking the capacitor elements 18 to 1c, depending on the case.

The tongues may be arranged, for example, so as to be distributed to the right and left sides of the anode lead frame at intervals of -stages.

Further, unlike the above embodiment, each capacitor element 1 a
= 1c may be laminated in advance via a conductive adhesive, and then the capacitor element laminate 12 may be attached to the anode lead terminal 13 and the cathode lead terminal 14.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to stack a plurality of flat capacitor elements while electrically connecting them in parallel without applying almost any mechanical stress to the solid electrolyte made of conductive polymer. , a solid electrolytic capacitor with a high capacitance and a low failure rate while being thin as a whole is provided.

[Brief explanation of drawings]

Figures 1 to 5 relate to embodiments of the present invention,
Figure 1 is a perspective view showing the capacitor element stack and each lead terminal separated, Figure 2 is a side view of the capacitor element stack, and Figure 3 is the capacitor element stack housed in the outer case. 4 is an explanatory diagram for explaining the state in which each lead terminal is separated from the lead frame, FIG. 5 is an external perspective view showing a chip type solid electrolytic capacitor as a final product, and 6iii1 is a flat FIG. 2 is a perspective view showing a capacitor element with its constituent elements cut away. In the figure, 1 is a capacitor element, 2 is an electrode foil, 3 is an anode lead, 4 is a solid electrolyte, 5 is a carbon layer, 6 is a silver layer, 7 is a cathode layer, 11 is a conductive adhesive material, 12 is a capacitor element lamination body, 13 is an anode lead terminal, 13a to 13c are tongue pieces,
14 is a cathode lead terminal, 14a is a cathode layer support surface, 15 is a lead frame, 16 is an undercoat resin, 17 is an exterior case,
18 is a sealing resin. Patent applicant Elnor Co., Ltd. Patent applicant Asahi Glass Co., Ltd. Agent Patent attorney Takuya Ohara Figure 4 Figure 5

Claims (2)

[Claims] (1) An anode lead is attached to a predetermined part of a flat electrode foil, a solid electrolyte made of a conductive polymer is formed around the electrode foil, and a cathode layer made of carbon, silver, etc. is formed on the solid electrolyte. A solid electrolytic capacitor having a plurality of flat capacitor elements formed by forming a capacitor element, a capacitor element laminate in which the plurality of flat capacitor elements are laminated with their respective cathode layers interposed via a conductive adhesive, and an external drawer. a lead frame having an anode lead terminal and a cathode lead terminal formed on the same end;
The anode lead terminal has a plurality of tongue pieces at different heights for attaching the anode leads corresponding to the anode leads of each of the capacitor elements, and the cathode lead terminals are attached to the cathode layer of the capacitor element stack. In addition to attaching the capacitor element with a conductive adhesive, each anode lead of the capacitor element is welded to the corresponding tongue piece, and the capacitor element laminate is housed in an exterior case, and the capacitor element is separated from the lead frame. A solid electrolytic capacitor characterized in that an anode lead terminal and a cathode lead terminal are bent along the side surface of the exterior case. (2) The solid electrolytic capacitor according to claim 1, wherein the plurality of tongue pieces are arranged in a stepped manner at the end of the anode lead terminal.