Method for producing low leakage winding type solid electrolytic capacitor

Abstract

The invention provides a method for producing a low leakage winding type solid electrolytic capacitor. The method comprises the following steps: step 1), cutting; and step 2), element preparation: performing formation, drying, pretreatment, monomer impregnation, oxidizer impregnation, polymerization, assembly and aging on a core package; performing formation, and immersing the core package after winding into a formation electrolyte to electrify, wherein the electrifying voltage is the withstand voltage of an anode foil, and the formation electrolyte is the aqueous solution of ammonium dihydrogen phosphate; and performing pretreatment: immersing the core package into a mending agent, drying the core package, and after that, forming a layer of insulating film which is less than or equal to 20nm on an aluminum foil surface. Compared with the previous products, the method of the invention does not require a high temperature of 230 to 300 DEG C after mending an oxide film by a formation process, thus the damage to the oxide film is less; and besides, the pretreatment is added before impregnating the monomer, an ultra-thin insulating film covering the surface of the aluminum foil can be formed, so that the defects of the oxide film can be further reduced, therefore, the leakage of solid electrolytic capacitor products produced by the invention is 20% to 50% smaller than that of ordinary products.

Description

technical field [0001] The invention relates to a method for manufacturing a capacitor, in particular to a method for manufacturing a low-leakage winding solid electrolytic capacitor. Background technique [0002] Compared with traditional products, solid aluminum electrolytic capacitors have the advantages of small equivalent series resistance, good high frequency characteristics and safe use. However, conductive polymers do not have the function of repairing the oxide film. The "self-healing" of solid aluminum electrolytic capacitors is that the conductive polymer with a large leakage current evaporates or decomposes into an insulating substance when heated, so its leakage current is an order of magnitude higher than that of liquid products. [0003] On the one hand, the large leakage current of solid aluminum electrolytic capacitors will cause the internal temperature of the capacitor to rise, accelerate the aging of the electrolyte, and shorten the life of the capacitor;...

AI Technical Summary

Problems solved by technology

[0005] In the existing scheme, the cutting burr of the anode foil is 0.02mm~0.03mm, which makes the leakage of the product difficult to control

[0006] In the existing solution, because the material of the electrolytic paper is wood fiber, it will react with the oxidant, resulting in insufficient monomer polymerization and poor product characteristics.

The carbonization process requires a high temperature of about 230°C~300°C for 2 hours to 3 hours, which consumes a lot of energy and has low efficiency. If the temperature is too high, it is easy to cause the guide pin to be covered with tin and melt and form nodules (the guide pin is made of copper plated iron core. Re-tinning, the melting point of tin is about 230°C), and it will damage the oxide film of the anode foil of the element and need to be repaired again, which further increases the production time

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