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CN-121983429-A - High-reliability liquid capacitor and preparation method thereof

CN121983429ACN 121983429 ACN121983429 ACN 121983429ACN-121983429-A

Abstract

The invention discloses a high-reliability liquid capacitor and a preparation method thereof, and relates to the technical field of electrolytic capacitors. The high-reliability liquid capacitor comprises a core package and an aluminum shell, wherein the core package comprises anode foil, cathode foil, electrolyte solution and electrolytic paper, and the preparation method comprises formation, winding and compounding, immersion liquid, vacuum heat sealing, cooling and solidification.

Inventors

  • WANG YONGMING

Assignees

  • 上海永铭电子股份有限公司

Dates

Publication Date
20260505
Application Date
20260224

Claims (10)

  1. 1. The high-reliability liquid capacitor is characterized by comprising a core package and an aluminum shell, wherein the core package comprises anode foil, cathode foil, electrolyte solution and electrolytic paper; the anode foil is formed into aluminum foil; the cathode foil is aluminum foil; The electrolyte solution comprises, by weight, 70-90 parts of ethylene glycol, 1-3 parts of a modified polymer additive, 5-10 parts of ammonium sebacate, 1-6 parts of ammonium pentaborate, 0.5-3 parts of a waterproof agent, 0.2-0.5 part of a hydrogen eliminating agent, 0.5-2 parts of a forming agent and 1-3 parts of nano alumina; The modified polymer additive is polyvinyl fluoride alcohol-vinyl imidazolium hydroxide copolymer.
  2. 2. The high reliability liquid capacitor of claim 1 wherein said electrolyte solution is prepared by a process comprising the steps of: according to the weight proportion of the components, heating glycol to 50-70 ℃, adding ammonium sebacate, heating to 70-90 ℃ after complete dissolution, keeping stirring, sequentially adding a waterproof agent and nano alumina, heating to 125-135 ℃ and stirring for dissolution, adding a modified polymer additive, heating to 155-165 ℃, cooling to 120-140 ℃ after dissolution, adding ammonium pentaborate, cooling to 90-110 ℃, adding a hydrogen eliminating agent and a forming agent, stirring uniformly, and cooling to room temperature to obtain an electrolyte solution.
  3. 3. The high-reliability liquid capacitor according to claim 1, wherein the waterproof agent is one or more of mannitol and phosphoric monoester; The hydrogen eliminating agent is one or more of p-nitrobenzoic acid, p-nitrophenol and dinitrobenzene; The forming agent is ammonium hypophosphite.
  4. 4. The high reliability liquid capacitor of claim 2 wherein the method of preparing the modified polymeric additive comprises the steps of: A1, adding trifluoro vinyl acetate, azodiisobutyronitrile and methanol into a reaction kettle for blending, heating to 60-70 ℃ under the nitrogen atmosphere, carrying out heat preservation reaction for 3-8 hours, and washing with n-hexane for multiple times to obtain the poly trifluoro vinyl acetate; A2, adding the poly (vinyl acetate fluoride), methanol and sodium hydroxide into a reaction kettle for blending, carrying out heat preservation reaction at 40-60 ℃ for 40min-1h, regulating the viscosity of the system by using acetone, and carrying out repeated precipitation and washing by using diethyl ether, and carrying out vacuum drying to obtain modified polyvinyl alcohol; a3, adding modified polyvinyl alcohol, deionized water, nitric acid, ceric ammonium nitrate and N-vinylimidazole into a reaction bottle, heating to 35-45 ℃ in a nitrogen atmosphere, stirring for 4-6h, precipitating with methanol for multiple times, washing, extracting and purifying to obtain an intermediate; A4, reacting the intermediate and the bromo-n-butane for 4-8 hours at 60-80 ℃, distilling under reduced pressure, washing with diethyl ether for multiple times, and vacuum drying to obtain the polyvinyl fluoride alcohol-vinyl imidazole bromoonium copolymer, mixing the polyvinyl fluoride alcohol-vinyl imidazole bromoonium copolymer, ethanol and sodium hydroxide in a reaction kettle, stirring and reacting for 2-3 hours, and carrying out suction filtration, rotary steaming, column chromatography elution and vacuum drying to obtain the modified organic additive.
  5. 5. The high reliability liquid capacitor of claim 4 wherein the weight ratio of added trifluoroacetate to azobisisobutyronitrile in A1 is 100:2-5.
  6. 6. The high reliability liquid capacitor of claim 4 wherein the weight ratio of added poly (vinyl trifluoroacetate) and sodium hydroxide in A2 is 100:0.5-1.
  7. 7. The high-reliability liquid capacitor according to claim 4, wherein the concentration of nitric acid in A3 is 6.3wt%, and the weight ratio of modified polyvinyl alcohol, ceric ammonium nitrate and N-vinylimidazole is 20-30:9-10:15.
  8. 8. The high-reliability liquid capacitor according to claim 4, wherein the molar ratio of the intermediate to the bromo-n-butane in A4 is 5:5-7; the adding mole ratio of polyvinyl fluoride alcohol-vinyl imidazole bromonium copolymer and sodium hydroxide is 5:5-6.
  9. 9. The method for manufacturing a highly reliable liquid capacitor as claimed in any one of claims 1 to 8, comprising the steps of: S1, cleaning an aluminum foil with absolute ethyl alcohol, and then placing the aluminum foil into a formation liquid for formation to obtain an anode foil; s2, sequentially assembling, compounding and winding the anode foil, the electrolytic paper and the cathode foil in sequence, drying, dehumidifying and immersing in electrolyte to obtain a core package; s3, coating an adhesive in the aluminum shell, packaging the core into the aluminum shell of the capacitor, performing vacuum heat sealing, and naturally cooling to obtain the high-reliability liquid capacitor.
  10. 10. The method for manufacturing a highly reliable liquid capacitor according to claim 9, wherein the aluminum foil formation in S1 is performed by six-stage formation, wherein the composition of the primary to quaternary formation liquids is 0.1 to 0.5wt% of citric acid or citrate and 0.3 to 1wt% of phosphoric acid or phosphate, and the composition of the five to six-stage formation liquids is 5 to 10wt% of boric acid and 2.5 to 5wt% of ammonium pentaborate; the adhesive in S3 is an acrylic adhesive.

Description

High-reliability liquid capacitor and preparation method thereof Technical Field The invention relates to the technical field of electrolytic capacitors, in particular to a high-reliability liquid capacitor and a preparation method thereof. Background As an indispensable passive component in electronic circuits, the technical development of liquid capacitors has been around the core goals of improving reliability, prolonging life and adapting to severe application environments. Although the traditional liquid aluminum electrolytic capacitor has the advantages of high capacitance-volume ratio, high rated voltage, low cost and the like, the inherent liquid electrolyte system is easy to cause performance degradation and even failure under the stress of high temperature, high frequency, high ripple current and long-term continuous operation, and becomes a bottleneck for further application in the fields of electronics, aerospace and the like. The electrolyte of the liquid capacitor consists of a solvent and a solute, wherein the common solvent is ethylene glycol, gamma-butyrolactone and the like, the solute mainly adopts boric acid, borate, carboxylate and the like, and in the use of the liquid capacitor, small leakage current exists under the applied voltage, hydrogen is generated at a cathode foil, and the performance of the capacitor is reduced. In the prior art, a hydrogen eliminator is generally introduced, and electrons are consumed to prevent hydrogen from being generated, but the voltage range and the temperature range of the hydrogen eliminator are limited, and oxidation property of the hydrogen eliminator can corrode an anode foil oxide film in long-term use, so that the equivalent series resistance is increased, and the capacity is reduced. Disclosure of Invention The invention aims to provide a high-reliability liquid capacitor and a preparation method thereof, which solve the following technical problems: leakage current can occur in the prior liquid capacitor in use, and the problem is difficult to be comprehensively solved by a single hydrogen eliminator. The aim of the invention can be achieved by the following technical scheme: The high-reliability liquid capacitor comprises a core package and an aluminum shell, wherein the core package comprises anode foil, cathode foil, electrolyte solution and electrolytic paper; the anode foil is formed into aluminum foil; the cathode foil is aluminum foil; The electrolyte solution comprises, by weight, 70-90 parts of ethylene glycol, 1-3 parts of a modified polymer additive, 5-10 parts of ammonium sebacate, 1-6 parts of ammonium pentaborate, 0.5-3 parts of a waterproof agent, 0.2-0.5 part of a hydrogen eliminating agent, 0.5-2 parts of a forming agent and 1-3 parts of nano alumina; The modified polymer additive is polyvinyl fluoride alcohol-vinyl imidazolium hydroxide copolymer. As a further scheme of the invention, the preparation method of the electrolyte solution comprises the following steps: According to the weight proportion of the components, heating glycol to 50-70 ℃, adding ammonium sebacate, heating to 70-90 ℃ after complete dissolution, keeping stirring, sequentially adding a waterproof agent and nano alumina, heating to 125-135 ℃ for stirring and dissolving, adding a modified polymer additive, heating to 155-165 ℃, cooling to 120-140 ℃ after dissolving, adding ammonium pentaborate, cooling to 90-110 ℃, adding a hydrogen eliminating agent and a forming agent, stirring uniformly, and cooling to room temperature to obtain an electrolyte solution. As a further scheme of the invention, the waterproof mixture is any one or more of mannitol and phosphoric monoester; The hydrogen eliminating agent is one or more of p-nitrobenzoic acid, p-nitrophenol and dinitrobenzene; The forming agent is ammonium hypophosphite. As a further scheme of the invention, the preparation method of the modified polymer additive comprises the following steps: A1, adding trifluoro vinyl acetate, azodiisobutyronitrile and methanol into a reaction kettle for blending, heating to 60-70 ℃ under the nitrogen atmosphere, carrying out heat preservation reaction for 3-8 hours, and washing with n-hexane for multiple times to obtain the poly trifluoro vinyl acetate; A2, adding the poly (vinyl acetate fluoride), methanol and sodium hydroxide into a reaction kettle for blending, carrying out heat preservation reaction at 40-60 ℃ for 40min-1h, regulating the viscosity of the system by using acetone, and carrying out repeated precipitation and washing by using diethyl ether, and carrying out vacuum drying to obtain modified polyvinyl alcohol; a3, adding modified polyvinyl alcohol, deionized water, nitric acid, ceric ammonium nitrate and N-vinylimidazole into a reaction bottle, heating to 35-45 ℃ in a nitrogen atmosphere, stirring for 4-6h, precipitating with methanol for multiple times, washing, extracting and purifying to obtain an intermediate; A4, reacting the intermediate and the bromo-