CN108648913B

CN108648913B - Solid-state aluminum electrolytic capacitor

Info

Publication number: CN108648913B
Application number: CN201810309964.2A
Authority: CN
Inventors: 汤依伟; 蔡锦丰; 彭小昕; 夏凯翔
Original assignee: YIYANG WANJINGYUAN ELECTRONICS Co Ltd
Current assignee: YIYANG WANJINGYUAN ELECTRONICS Co Ltd
Priority date: 2018-04-09
Filing date: 2018-04-09
Publication date: 2020-01-21
Anticipated expiration: 2038-04-09
Also published as: CN108648913A

Abstract

The utility model provides a solid-state aluminum electrolytic capacitor, is formed the core package by positive negative pole paper tinsel and electrolytic paper winding, and the riveting has the lead wire on the positive negative pole paper tinsel, and the lead wire on the core package passes gluey consent and is in the same place with the aluminium hull assemblage, wherein, the core package internal growth has conducting polymer, and the aluminium foil of core package upper and lower surface cuts the department shaping and has polyimide material flooding protective layer, polyimide material flooding protective layer heats to 220 ~ 320 ℃ dehydration shaping behind the soluble polyamic acid solution by the upper and lower surface flooding of the core package of coiling shaping. The invention can effectively improve the high ripple current resistance of the product; meanwhile, the position defect of the cut edge can be effectively protected, the leakage current of the product is reduced, and the reliability of the product is improved.

Description

Solid-state aluminum electrolytic capacitor

Technical Field

The invention relates to the technical field of preparation of solid-state capacitors, in particular to a solid-state aluminum electrolytic capacitor.

Background

In the prior art, the core package of the solid-state aluminum electrolytic capacitor is mainly formed by riveting a lead wire with a cut aluminum foil and winding the aluminum foil with an electrolytic paper, wherein the aluminum substrate on the detachable edge is exposed due to the fact that the aluminum foil is directly cut and formed on the cut edge of the aluminum foil, and the defect of the aluminum substrate is repaired by adopting a formation mode at present, so that the leakage current of a product is reduced.

However, the aluminum foil formed by the formation method still has a great risk of defects, the aluminum oxide film grown on the surface of the aluminum foil through short-time formation is not necessarily completely covered, and the aluminum oxide film has different thicknesses, so that the product still has a great risk of leakage current, and the cutting burrs existing in the product are also main factors causing breakdown failure of the capacitor.

Disclosure of Invention

The present invention is directed to a solid-state aluminum electrolytic capacitor, which has the characteristics of low leakage current, high reliability, and high ripple current resistance, and can be used to solve the above-mentioned drawbacks in the background art.

The technical problem solved by the invention is realized by adopting the following technical scheme:

the utility model provides a solid-state aluminum electrolytic capacitor, is rolled up by positive negative pole paper tinsel and electrolysis paper and forms the core package, and the riveting has the lead wire on the positive negative pole paper tinsel, and the lead wire on the core package passes gluey consent and assembles together with the aluminum hull, wherein, the core package internal growth has conducting polymer, and the aluminium foil of core package upper and lower surface cuts the department shaping and has polyimide material flooding protective layer. The polyimide material dipping protective layer is formed by dipping the upper surface and the lower surface of a winding core bag in a soluble polyamic acid solution, and then heating to 220-320 ℃ for dehydration forming; the soluble polyamic acid solution is prepared by adding dianhydride and diamine into a polar solvent according to the mass ratio of 1: 0.5-1: 2, and controlling the temperature to be 3-15 ℃ for low-temperature polycondensation.

In the present invention, the core package dehydration forming temperature after completion of the impregnation is preferably 300 ℃.

In the present invention, the preferable addition mass ratio of dianhydride and diamine in the soluble polyamic acid is 1: 1.2.

In THE present invention, THE polar solvent is one of DMF, DMAC, NMP or THE he/methanol mixed solvent, and is preferably DMF.

In the present invention, the temperature of the low-temperature polycondensation operation is preferably 6 ℃.

A preparation method of a solid-state aluminum electrolytic capacitor is used for preparing the solid-state aluminum electrolytic capacitor and comprises the following operation steps:

1) the anode foil, the cathode foil and the electrolytic paper are cut into the width specified by the process according to the process requirements.

2) Riveting a positive guide pin nail on the anode aluminum foil, riveting a negative guide pin on the cathode aluminum foil, and clamping the electrolytic paper between the anode foil and the cathode foil and winding the electrolytic paper into a cylindrical core package.

3) And immersing the wound core cladding into formation electrolyte for electrifying formation, repairing the defects of the electrode foil and growing an aluminum oxide film on the defect parts.

4) And carbonizing the formed core package to carbonize the electrolytic paper therein.

5) And respectively soaking the upper surface and the lower surface of the carbonized core bag in the soluble polyamic acid solution prefabricated by the method, taking out the core bag when the soluble polyamic acid solution is uniformly soaked in the core bag, and heating and dehydrating to form the polyimide protective layer.

6) Impregnating the core wrap treated in the step 5) with a pretreatment agent, and then impregnating the core wrap with a conductive high molecular monomer and an oxidant.

7) And (3) polymerizing and assembling the core cladding treated by the impregnated conductive high molecular monomer and the oxidant in sequence, cleaning the surfaces of the aluminum shell and the lead, and then sending the core cladding into an aging treatment unit for aging treatment to insulate the polymer at the defective part of the aluminum foil, thus obtaining the finished product of the solid aluminum electrolytic capacitor.

Has the advantages that: the solid-state aluminum electrolytic capacitor prepared by the invention has a simple structure, the preparation process is convenient and easy to operate, the polyimide protective layers are formed on the upper surface and the lower surface of the core cladding, on one hand, the structure can form a heat conduction path by contacting the polyimide protective layer with an aluminum shell, so that the product can resist high ripple current, on the other hand, the polyimide protective layer can cover the cutting part of the aluminum foil, the insulation performance of the polyimide is utilized to protect the cutting defect position, the leakage current of the product is reduced, the probability of product failure caused by burrs is reduced, and the reliability of the product is improved.

Drawings

Fig. 1 is a schematic diagram of a core package structure of a solid-state aluminum electrolytic capacitor according to the present invention.

Wherein: 1. a core package; 2. a polyimide material impregnation protective layer; 3. and (6) guiding the needle.

Detailed Description

In order to make the technical means, the original characteristics, the achieved purposes and the effects of the invention easy to understand, the invention is further described with reference to the specific embodiments and the drawings.

In the examples, the same batch of 25V-470 μ F solid aluminum electrolytic capacitors prepared by the structure and preparation method of the present invention is taken as an example, and a conventional batch of 25V-470 μ F solid aluminum electrolytic capacitors prepared by the conventional preparation method is taken as a technical comparison.

In the embodiment, when the structure and the preparation method of the invention are used for preparing the solid-state aluminum electrolytic capacitor, the soluble polyamic acid solution is prepared firstly, and the dianhydride and the diamine are added into the DMF solvent according to the mass ratio of 1:1.2, and the temperature is controlled at 6 ℃ for low-temperature polycondensation.

Cutting an anode foil, a cathode foil and electrolytic paper into a process specified width according to process requirements, riveting a positive guide pin on the anode aluminum foil, riveting a negative guide pin on the cathode aluminum foil, clamping the electrolytic paper between the anode foil and the cathode foil, winding the electrolytic paper into a cylindrical shape, immersing a wound core package into a formed electrolyte to carry out electrification to repair the defects of the electrode foil, growing an aluminum oxide film on the defect part, wherein the electrification voltage is the withstand voltage of the anode foil during the formation operation; the formation electrolyte is an aqueous solution of ammonium dihydrogen phosphate, and the mass fraction of the formation electrolyte is 0.6%; drying for 2h at 150 ℃ after formation; and carbonizing the dried core package to carbonize the electrolytic paper therein.

Then, the upper surface and the lower surface of the core package subjected to the carbonization treatment of the electrolytic paper are respectively soaked in a prefabricated soluble polyamic acid solution, the core package is taken out when the soluble polyamic acid solution is uniformly soaked in the core package, and the core package is heated to 300 ℃ for dehydration forming, so that polyimide protective layers are formed on the upper surface and the lower surface of the core package, and the forming structure is shown in fig. 1. Then, immersing the core wrap into a monomer ethanol solution for impregnation, firstly, immersing for 2-3 min under the conditions of normal temperature and normal pressure, and then, drying for 1-2 h under the condition of 50-60 ℃ to complete the impregnation operation; immersing the core package impregnated with the monomer ethanol solution into an oxidant solution, impregnating for 8-10 min under the vacuum condition of air pressure of-80 to-30 kPa, putting the core package into an oven for polymerization, sealing the polymerized core package in an aluminum shell with a rubber plug for aging, controlling the aging temperature to be 105 ℃ and the aging voltage to be less than or equal to 1.2 times of the working voltage, and aging for 120-130 min in total to obtain the finished product of the solid aluminum electrolytic capacitor.

The solid capacitor prepared by the method and products of different batches produced by the traditional process are randomly sampled to obtain 10 individual units, and the measured data of the two units are compared as shown in the following table:

TABLE 1 Electrical Properties of the 25V-470 uF products of the present invention and those made by conventional processes

The data show that the product manufactured by the process is comprehensively superior to the product manufactured by the traditional process, the product consistency is far superior to the traditional process, the performance is more stable, the yield is higher, and the leakage current value is lower.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A solid-state aluminum electrolytic capacitor is characterized in that a core package is formed by winding positive and negative electrode foils and electrolytic paper, leads are riveted on the positive and negative electrode foils, the leads on the core package penetrate through glue plug holes and are assembled with an aluminum shell, wherein a conductive polymer grows in the core package, polyimide material impregnation protective layers are formed at aluminum foil cutting positions of the upper surface and the lower surface of the core package, the polyimide material impregnation protective layers adopt a soluble polyamide acid solution as an impregnation solution, the upper surface and the lower surface of the core package formed by winding are uniformly impregnated in the impregnation solution and then taken out, and the core package is heated to 220-320 ℃ for dehydration forming; THE soluble polyamic acid solution is prepared by adding one of DMF, DMAC, NMP or THE/methanol mixed solvent into dianhydride and diamine according to THE mass ratio of 1: 0.5-1: 2, and carrying out low-temperature polycondensation at THE temperature of 3-15 ℃.

2. The solid aluminum electrolytic capacitor according to claim 1, wherein the dianhydride and the diamine are added in a mass ratio of 1: 1.2.

3. The solid state aluminum electrolytic capacitor of claim 1 wherein the temperature of the low temperature polycondensation operation is 6 ℃.

4. The solid aluminum electrolytic capacitor according to claim 1, wherein the core package dehydration forming temperature after completion of the impregnation is 300 ℃.