JPS6034809B2 - Manufacturing method of solid electrolytic capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an electrolytic capacitor, particularly an aluminum mass electrolytic capacitor.

Aluminum or tantalum group electrolytic capacitors are made by forming an oxide film (N203 or Ta205) on an aluminum or tantalum anode by electrolytic oxidation, depositing Mn02 as an electrolyte on this, and then forming a graphite layer and a silver cathode layer on top of it. This is the structure formed.

When manufacturing such solid electrolytic capacitors, conventionally, a conductive wire for supporting the anode plate is joined to an aluminum anode plate by electric welding such as percussion welding, and the conductor wire is held by an external jig to expand the surface area of the anode plate. After forming a yield zone layer by immersing it in an etching solution or an electrolyte solution for forming the peaks 203, and further forming a Mn02 layer, a graphite layer, and a cathode layer, the conductive wire is cut to an appropriate length. An anode lead terminal piece is bonded to the conducting wire, and a cathode lead terminal piece is bonded to the cathode, and then the capacitor element is covered by molding with epoxy resin or the like. In the etching process for expanding the surface area of the anode plate in such conventional manufacturing methods or the chemical conversion process for forming AI203, the joint portion of the anode plate supporting conductor wire bonded to the aluminum anode plate is exposed to an etching solution or an electrolytic solution. If it comes into contact with the capacitor, this portion will corrode or insulation failure will occur during chemical formation, and a good oxide film will not be formed, making it impossible to obtain the desired capacitor characteristics. In order to eliminate such problems, conventionally, the upper part of the anode plate where the conductive wires meet is coated with polyfluoroethylene paint or the like for protection, and then the anode plate is immersed in an etching solution or an electrolytic solution. Therefore, the upper part of the anode plate covered with protective paint does not function as a capacitor and becomes a useless part. Conventionally, this protective coating covers about 1.5 ribs on the upper part of the anode slope, which accounts for about 40% of the anode plate (about 2 x 1.5 x 3.5 to 4 legs) of a small capacitor. An object of the present invention is to reduce the size of a capacitor by eliminating the unnecessary parts provided by the above-mentioned protective coating.

Therefore, in the present invention, {a} The protrusions of a substrate formed of an anode body metal and having a plurality of protrusions for configuring anode plates are immersed in an etching solution to form a large number of protrusions on the surface of the protrusions. a step of forming grooves to expand the surface area; 'b-a step of immersing the protrusion in an oxidizing electrolyte to form an oxide film on the protrusion; {c} an oxide film formed on the protrusion; A step of forming an electrolyte layer, a graphite layer, and a cathode layer thereon to form a capacitor element, {d' A step of cutting and separating the capacitor element portion on the substrate from the substrate after forming the capacitor element, 'e} Above A method for manufacturing a solid electrolytic capacitor, comprising: a step of joining the cut and separated capacitor element to each lead terminal piece of a lead frame in which cathode and anode lead terminal pieces are integrally molded in alternating succession; {f} an exterior packaging process; And the above {
d) In the lead terminal piece bonding step, the anode IJ-de terminal is directly bonded to the exposed portion of the substrate on the cut separation surface of the capacitor element using solder or ultrasonic solder.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

The aluminum substrate 1 is formed with a number of protrusions 3 protruding downward from the frame for forming an anode plate. The upper continuous band-shaped portion of the aluminum substrate 1 is held and the lower protruding portion 3 for forming the anode plate is immersed in an etching solution to form a large number of grooves 2 on the substrate surface and enlarge the substrate surface (Fig. 41). ). Next, the protrusion 3 for forming the anode plate of the aluminum substrate 1 is similarly immersed in an electrolytic solution for electrolytic oxidation to form an oxide film 4 (N203) on the surface of the substrate. (Second
figure). Next, the anode plate forming protrusion 3 on which the oxide film 4 was formed
was soaked in Mn(NQ)2 solution and then 200q
Mn02 electrolyte layer 5 is formed by thermal decomposition at a temperature of o~400°C.
A graphite layer 6 is applied thereon as a cathode, and a cathode layer 7 of silver is further formed thereon (FIG. 3). In this way, capacitor element 9 is formed on aluminum substrate 1 (Fig. 3).
. Next, this capacitor element 9 is cut and separated from the aluminum substrate to expose the aluminum substrate surface 8 at the cut surface (FIG. 4). Next, a large number of a pair of cathode lead terminal pieces 10 and anode lead terminal pieces 11 are integrally formed, and the board frame 12 and the capacitor element 9 are joined (
Figure 5). At this time, the cathode lead terminal piece 1 of the lead frame 12 is bonded to the silver cathode layer 7 of the capacitor element 9 by dip soldering, and the anode lead terminal piece 11 is bonded to the exposed surface 8 of the aluminum substrate using aluminum solder or ultrasonic solder. and are joined together. Next, the exterior portion 13 is formed by molding epoxy resin or the like (FIG. 6). According to the method for manufacturing an aluminum solid electrolytic capacitor as described above, the anode plate is processed in a solution such as an etching solution or an electrolytic solution for chemical formation in order to cut and separate the capacitor element from the aluminum substrate after forming the capacitor element. Carrying conductor wires are no longer required.

Therefore, the aluminum substrate does not contain any dissimilar metals other than aluminum in the part immersed in the solution, and therefore corrosion of the anode plate due to the reaction between dissimilar metals and the solution caused by leakage current due to defective protective coating and defective oxide film formation are completely prevented. As a result, product characteristics are stabilized and reliability is increased. In addition, since the conventional protective coating process for the joint between the anode plate supporting conductor and the aluminum anode plate is no longer necessary, the manufacturing process is simplified, work efficiency is improved, and the cost associated with the protective coating process is reduced. In addition, the capacitor element has no unnecessary parts covered with protective coating, so the product can be made smaller.

[Brief explanation of drawings]

1 to 6 are diagrams sequentially showing the shape state of a capacitor manufactured by the method of the present invention at each step. 1... Aluminum substrate, 2... Groove,
3... Protrusion for anode plate configuration, 4...
Oxide film, 5... Electrolyte layer, 6... Graphite layer, 7... Cathode layer, 11...
・Anode lead terminal, 12...Lead frame,
13...exterior part. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Scope of Claims] 1 (a) The protruding parts 3 of the substrate 1, which is formed of an anode body metal and has a plurality of protruding parts 3 for forming an anode plate, are immersed in an etching solution to form a large number of protrusions on the surface of the protruding parts. (b) forming an oxide film 4 on the protrusion 3 by immersing the protrusion 3 in an oxidizing electrolyte; (c) forming the oxide film 4 on the protrusion 3; forming an electrolyte layer 5, a graphite layer 6, and a cathode layer 7 on the oxide film 4 formed above to form a capacitor element 9; (d) forming a capacitor element 9 portion on the substrate 1; Later, a step of cutting and separating the capacitor element 9 from the substrate 1, (e) cutting and separating the capacitor element 9 into lead terminal pieces 10, 11 for cathode and anode.
A method for manufacturing a solid electrolytic capacitor, comprising: (f) an exterior step of joining the lead terminal pieces 10 and 11 of the lead frame 12 which are integrally molded in a continuous and alternating manner;
d) In the lead terminal piece joining process, the anode lead terminal 1
A method for manufacturing a solid electrolytic capacitor, in which a solid electrolytic capacitor is directly bonded to an exposed portion of a substrate on a cut separation surface of a capacitor element 9 using solder or ultrasonic solder.