JP4557523B2 - Manufacturing method of solid electrolytic capacitor - Google Patents

Description

  The present invention relates to a method for producing a solid electrolytic capacitor capable of thinly and uniformly applying a silver paste on a carbon layer.

As shown in FIG. 1, the solid electrolytic capacitor (10) is formed by sequentially laminating a chemical conversion film (21), a solid electrolyte layer (22), and a carbon layer (23) on an anode body (20) made of a valve metal. A silver paste layer (30) is formed on the surface of the capacitor element (11), and as shown in FIG. 2, the lead frames (40) and (42) are bonded, covered with a resin (50), and subjected to an aging treatment. Created in line.
The silver paste layer (30) is formed by immersing the capacitor element (11) in a silver paste made of silver, a binder, and a solvent (volatile component) that dissolves the binder.
The silver paste layer (30) is formed into a silver paste layer by immersing and pulling up the capacitor element (11) up and down in silver paste to form a silver paste layer (30) on the surface of the capacitor element (11). There is a technique to apply thinly efficiently.

Japanese Patent Laid-Open No. 11-121284 (full text)

When the silver paste layer is formed by immersing and pulling up the capacitor element in the silver paste while vibrating up and down, a large amount of silver paste remains on the bottom surface of the capacitor element, and the silver paste layer may be formed thick. is there. In this case, it is necessary to add a step of wiping off the silver paste adhering to the bottom surface with a wiper or the like. Further, when an attempt is made to form a silver paste layer only by vertical vibration, bubbles may be generated in the silver paste and may remain in the silver paste layer where the bubbles are formed.
In addition, since the solid electrolytic capacitor is required to be downsized, it is also required that the silver paste layer (30) be as thin and uniform as possible. In order to form a thin silver paste layer, the viscosity of the silver paste may be lowered. However, when the viscosity of the silver paste is lowered, a portion where the silver paste does not adhere to the upper end portion of the capacitor element (11) indicated by a circle A in FIG.
These cause deterioration in quality of characteristics such as ESR (equivalent series resistance) of the solid electrolytic capacitor.
An object of the present invention is to provide a method for producing a solid electrolytic capacitor in which a silver paste can be applied thinly and uniformly on the surface of a capacitor element without applying omission.

The method for producing a solid electrolytic capacitor according to claim 1 of the present invention, the end face an anode lead (41) is an anode body conversion coating consisting implanted by a valve action metal, a solid electrolyte layer to form a carbon layer Solid electrolytic process including a step of forming a capacitor element, forming a silver paste layer on the outer periphery of the carbon layer by dipping and lifting the capacitor element in a silver paste, and electrically connecting a lead frame to the silver paste layer In the method of manufacturing a capacitor,
The silver paste layer is formed by immersing the capacitor element in the silver paste. After the capacitor element is pulled up from the silver paste, the capacitor element is rotated, and the silver paste that is excessively attached to the capacitor element is parallel to the anode lead. A step of shaking off by centrifugal force in the direction.

According to the manufacturing method of solid electrolytic capacitor according to claim 1 of the present invention, after pulling by immersing the capacitor element in the silver paste, by rotating the capacitor element, excess silver paste adhering to the capacitor element It is shaken off by centrifugal force. Thereby, the silver paste layer can be formed thin and uniformly.

  According to the method for producing a solid electrolytic capacitor of the present invention, in any case, the silver paste layer is uniformly applied to the capacitor element without leaving bubbles, and the thickness is about 80% to 150 μm. It can be formed in half or less (about 50 μm or less).

As a result, it is possible to improve the quality by improving the ERS characteristics and the like, and meet the demand for downsizing of the solid electrolytic capacitor.
Further, it is possible to prevent connection failure and deviation at the time of bonding the lead frame in the subsequent process, and to prevent inclination of the capacitor element during resin coating.
With these effects, the yield can be improved.

<Embodiment 1>
Embodiment 1 relates to an example in which a silver paste layer (30) is formed uniformly and thinly by applying vibration in the vertical and horizontal directions when the capacitor element (11) is immersed in the silver paste (31). is there.

As shown in FIG. 1, the solid electrolytic capacitor (10) is formed of valve metal such as Ta, Al, Nb, etc., and is subjected to electrolytic oxidation treatment on the surface of the anode body (20) to which the lead wire (41) is connected. Forming a dielectric conversion coating (21), and forming a solid electrolyte layer (22) made of an organic solid electrolyte such as an inorganic solid electrolyte of MnO ₂ or a conductive polymer on the dielectric conversion coating (21), The capacitor element (11) is formed by coating the carbon layer (23) on the solid electrolyte layer (22).

  A Ta sintered body can be exemplified as the valve metal as the anode, and polypyrrole as a conductive polymer can be exemplified as the solid electrolyte layer (22) as the cathode.

FIG. 3 shows an apparatus for forming a silver paste layer (30) on the capacitor element (11). The silver paste (31) is put in a container (69) whose upper surface is opened, and the capacitor element (11) is attached to the element vibration device (60) described in detail below and immersed in the silver paste (31). Is done.
The silver paste (31) can be composed of silver, a binder, and a solvent (nonvolatile component) that dissolves the binder. Examples of the binder include resin components such as an epoxy resin.
The viscosity of the silver paste (31) is preferably 3 to 300 poise. The viscosity of the silver paste (31) can be appropriately adjusted by changing the ratio with the solvent.

As shown in FIG. 3, the element vibration device (60) includes a clip portion (61) that sandwiches the lead wire (41) of the capacitor element (11) and a vertical addition that vibrates the held capacitor element (11) up and down. Vibrator (62), horizontal vibrator (65) that vibrates the held capacitor element (11) in the horizontal direction (horizontal direction), and the capacitor element (11) is moved up and down to form a silver paste (31) And an elevating unit (67) to be immersed in.
The clip part (61) can be exemplified by a spring type that sandwiches the lead wire (41) of the capacitor element (11). Further, the lead wire (41) may be attached by a screw or the like, or may be adsorbed by air.
The vertical vibrator (62) includes a pair of links (63) that sandwich and hold the clip portion (61) from the lateral direction, and an eccentric rotating plate (64) that is connected to the upper end of the link (63). The eccentric rotating plate (64) can be exemplified by a configuration that can be rotated by a motor (not shown). When the motor is driven, the eccentric rotating plate (64) rotates, and the clip portion (61) moves up and down together with the link (63). The longitudinal vibrator (62) may be an electromagnetic type.
An example of the lateral vibrator (65) is an ultrasonic generator (66). The ultrasonic generator (66) protrudes downward from the side surface of the clip part (61), applies ultrasonic waves to the lead wire (41) gripped by the clip part (61), and places the lead wire (41). The capacitor element (11) can be vibrated laterally by vibrating. The horizontal vibrator (65) may be a motor-driven type or an electromagnetic type, and as shown in FIG. 4, these horizontal vibrators (65) are directly placed on the clip part (61). Vibration may be applied.
The lifting unit (67) can be exemplified by a piston drive type. The lower end of the piston (68) is connected to the vertical vibrator (62), and by extending and contracting the piston (68), the part below the vertical vibrator (62) moves up and down as a whole. The capacitor element (11) held by the clip part (61) can be dipped in the silver paste (31) and pulled up.

As for the vibration of the capacitor element (11) when dipped in the silver paste (31), it is desirable that the vertical amplitude is 0.05 to 0.5 times the vertical length of the capacitor element (11). Further, the amplitude in the horizontal direction is preferably 0.01 to 0.5 times the width in the horizontal direction (vibration direction) of the capacitor element (11). For example, the vertical amplitude can be 0.1 to 1.0 mm, and the horizontal amplitude can be 0.05 to 0.5 mm.
The frequency is desirably 30 to 100 Hz in the vertical direction and 50 to 300 Hz in the horizontal direction.

In the element vibration device (60) configured as described above, when the lead wire (41) of the capacitor element (11) is sandwiched between the clip portions (61) and the vertical vibrator (62) and the horizontal vibrator (65) are operated, The capacitor element (11) vibrates in the vertical and horizontal directions.In this state, the lifting unit (67) is operated and immersed in the silver paste (31) in the container (69), and the capacitor element (11) The capacitor element (11) is lowered by the elevating unit (67) until the bottom and side surfaces are immersed in the silver paste (31).
Since the capacitor element (11) is immersed in the silver paste (31) while vibrating in the vertical and horizontal directions, the effective viscosity of the silver paste (31) decreases near the surface of the capacitor element (11). .
When the capacitor element (11) is immersed in the silver paste (31) up to the upper part of the side surface, the capacitor element (11) is vibrated not only vertically but also in the lateral direction. The silver paste (31) adheres to the middle circle A) without omission.

  After the capacitor element (11) is immersed in the silver paste (31) to the upper part of the side surface, the capacitor element (11) is raised by the elevating unit (67). Since the capacitor element (11) vibrates in the vertical and horizontal directions during this ascent, the extra silver paste (31) flows down from the element.

When the bottom surface of the capacitor element (11) moves away from the silver paste (31), it adheres to the bottom surface of the capacitor element (11) due to the lateral vibration of the capacitor element (11) and the surface tension of the silver paste (31). The excess silver paste (31) is dropped, and the silver paste (31) is applied uniformly and thinly on the surface of the capacitor element (11).
After lifting the capacitor element (11) from the silver paste (31), stop the vertical vibrator (62) and the horizontal vibrator (65), remove the capacitor element (11) from the clip part (61), and apply The silver paste layer (30) is formed on the surface of the carbon layer (23) of the capacitor element (11) by drying and curing the silver paste (31).

  Since the thickness of the formed silver paste layer (30) can be 50 μm or less, it is possible to meet the demand for downsizing of the solid electrolytic capacitor (10).

  In the capacitor element (11) having the silver paste layer (30) formed thereon, lead frames (40) and (42) are attached to the lead wire (41) and the silver paste layer (30) in a known manner, and the outer periphery is The solid electrolytic capacitor (10) is manufactured by covering the resin (50) by injection molding, bending the exposed portions of the lead frames (40) and (42), and performing an aging treatment.

  The produced solid electrolytic capacitor (10) was able to remarkably improve the yield due to poor ESR characteristics and poor appearance. Further, since the silver paste (31) can be applied to the capacitor element (11) by the dipping method, the productivity is excellent.

  In the above description, the capacitor element (11) is vibrated vertically and laterally, but the capacitor element (11) and the silver paste (31) may be relatively vibrated vertically and laterally, for example, The container (69) containing the silver paste (31) may be vibrated vertically and laterally. Alternatively, the capacitor element (11) can be vibrated up and down, the silver paste (31) can be vibrated in the horizontal direction, or the capacitor element (11) can be vibrated in the horizontal direction and the silver paste (31) can be vibrated up and down. Good.

<Embodiment 2>
In the second embodiment, when the silver paste (31) applied to the capacitor element (11) is dried, the excess silver paste (31) is shaken off to form the silver paste layer (30) uniformly and thinly. For example. Except for the procedure of forming the silver paste layer (30), the procedure is the same as that of the first embodiment.

  The silver paste layer (30) is formed by immersing the capacitor element (11) in the silver paste (31) contained in the container (69). When the capacitor element (11) is immersed in the silver paste (31), the capacitor element (11) may be vibrated in the vertical and horizontal directions as in the first embodiment, or may be vibrated only in one direction, or may be vibrated. It may be immersed without.

The capacitor element (11) pulled up from the silver paste (31) is attached to a rotating device (70) as shown in FIG. 5 until the silver paste (31) is dried, and the silver paste (31 ).
In the rotating device (70) of FIG. 5, disks (73) and (73) are arranged at a predetermined interval on a rotating shaft (72) connected to a motor (71), and between the disks (73) and (73), A plurality of housings (74) (74) can be attached. The lead wire (41) of the capacitor element (11) is connected to the housing (73).
When the rotating device (70) of FIG. 5 is used, a plurality of capacitor elements (11) are attached in advance to the casing (74), and the casing (74) is brought close to the silver paste (31) once. There is an advantage that a plurality of capacitor elements (11) can be immersed in the silver paste (31).

After the silver paste (31) is attached to the capacitor element (11), by driving the motor (71), the silver paste (31) is dried while being shaken off by centrifugal force due to rotation. As a result, a silver paste layer (30) is formed.
If excess silver paste (31) remains on the bottom surface of the capacitor element (11), it may be wiped off with a wiper or the like.

  When the viscosity of the silver paste (31) is about 200 poise, the conditions of the rotating device (70) are as follows: the distance from the rotating shaft (72) to the capacitor element (11) is 20 to 50 cm, and the rotational speed is 300 to 500 rpm. It is desirable to do. The rotation time is preferably 30 to 60 seconds.

The formed silver paste layer (30) is a uniform and thin film because excess silver paste (31) is shaken off.
After the silver paste layer (30) is formed, the capacitor element (11) may be removed from the casing (74).

  Since the thickness of the silver paste layer (30) can be reduced to 50 μm or less as described above, it is possible to meet the demand for downsizing of the solid electrolytic capacitor (10).

  The solid electrolytic capacitor (10) having the silver paste layer (30) produced as described above was able to remarkably improve the yield due to poor ESR characteristics and poor appearance. Moreover, since the silver paste (31) can be dried quickly, it is excellent in productivity.

<Embodiment 3>
Embodiment 3 relates to an example in which the silver paste layer (30) is formed uniformly and thinly using the stretchability of the stretchable material (80). Except for the procedure of forming the silver paste layer (30), the procedure is the same as that of the first embodiment.

  The silver paste layer (30) is formed by pressing the capacitor element (11) against the stretchable material (80) coated with the silver paste (31). Examples of the elastic material (80) include synthetic rubber and synthetic latex, and those having an elongation of 600% or more, desirably 900% or more are desirably used. The thickness of the stretchable material (80) is desirably 1 mm or less.

FIG. 6 is an explanatory view showing a silver paste layer forming step of the third embodiment. As shown in FIG. 6A, a silver paste (31) is applied in advance to the surface of the stretchable material (80).
When the capacitor element (11) is pressed against the stretchable material (80), a gap is formed between the side surface of the capacitor element (11) and the stretchable material (80). As shown, using a jig (81) having a recess (82) having a size corresponding to the thickness of the capacitor element (11) and the elastic material (80), the capacitor element (11) is connected to the elastic material (80 6 (b), the capacitor element (11) and the elastic material (80) are fitted in the recess (82), and the side surface of the capacitor element (11) and the elastic material are It is desirable that there is no gap between (80).

  By pressing the capacitor element (11) against the stretchable material (80), the silver paste (31) applied to the surface of the stretchable material (80) adheres to the capacitor element (11). The adhered silver paste (31) can be made much thinner than in the case of immersion, and the thickness of the formed silver paste layer (30) can be 50 μm or less. Therefore, it is possible to meet the demand for downsizing of the solid electrolytic capacitor (10).

  The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof. Moreover, each part structure of this invention is not restricted to the said Example, A various deformation | transformation is possible within the technical scope as described in a claim.

  The solid electrolytic capacitor manufacturing method of the present invention can form the silver paste layer (30) of the solid electrolytic capacitor (10) thinly and uniformly, and improve the yield by improving the ESR characteristics and reducing the appearance defect. In addition, the adhesion between the lead frame (42) and the silver paste layer (30) is improved, and the quality can be improved.

It is a partial cross section figure of a capacitor element. It is sectional drawing of a solid electrolytic capacitor. It is a side view of the apparatus which hold | grips and vibrates a capacitor | condenser element. It is a side view which shows the different Example of the apparatus which hold | grips and vibrates a capacitor | condenser element. It is a perspective view of the apparatus which rotates a capacitor | condenser element. It is explanatory drawing of the process of apply | coating a silver paste to a capacitor | condenser element using an elastic material.

Explanation of symbols

(10) Solid electrolytic capacitor
(11) Capacitor element
(23) Carbon layer
(30) Silver paste layer
(31) Silver paste
(41) Lead wire
(60) Element vibration device
(61) Clip part
(62) Vertical vibrator
(65) Horizontal vibrator
(67) Lifting unit
(70) Rotating device
(80) Elastic material

Claims (1)

A capacitor element is formed by forming a chemical conversion film (21), a solid electrolyte layer (22), and a carbon layer (23) on an anode body (20) made of a valve metal having an anode lead (41) planted on one end face. (11) is formed, the silver paste layer (30) is formed on the outer periphery of the carbon layer (23) by immersing and pulling up the capacitor element (11) in the silver paste (31), and the silver paste layer (30) In the method of manufacturing a solid electrolytic capacitor including the step of electrically connecting the lead frame (40) to
Formation of the silver paste layer (30) is performed by immersing the capacitor element (11) in the silver paste (31),
After pulling up the capacitor element (11) from the silver paste (31), the capacitor element (11) is rotated, and the silver paste (31) extraneous to the capacitor element (11) is parallel to the anode lead (41). A method for producing a solid electrolytic capacitor, comprising a step of shaking off by centrifugal force.

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