| Capacitors are important passive electronic components in circuits.Compared with resistors and inductors,capacitors are widely used in IC and electronic control.The principle is that the electrolyte forms a Kirchhoff capacitor with the anode foil aluminum base layer,and the aluminum oxide film is a dielectric.The ion migration in the electrolyte realizes the conduction of the circuit,and the electrolyte solvent is generally a capacitor level EG.The solute is mainly a substance containing a binary or polycarboxylic acid ammonium salt,and the substance has good solubility in a solvent such as ethylene glycol or glycerin.The subject preparation of an electrolytic capacitor electrolyte used at-40~105 ?,the flashover voltage of the electrolyte at least 480 V or more;The use of long chain polycarboxylate ammonium organics and polyols results in Z(-40?)/ Z(20?)? 10,(C(20?)-C(-40?))/ C(20?)? 20%,No obvious new ester formation is formed in the electrolyte at the low and high temperature environment,The electrolyte conductivity reaches 1.65 ms/cm,The capacitor life reaches 2000 hours at 105 ? and the working voltage reaches 400 V or more?The branched long chain dicarboxylic acid ammonium salt is synthesized by the cyclohexanone Fenton method.The mixed branched polycarboxylic acid ester is subjected to hydrolysis,saponification,acidification,fractionation and the like and 20% EG branched carboxylic acid ammonium salt electrolyte was prepared.The experiment shows that the yield of branched carboxylic acid is 83.9%,that the molar ratio of cyclohexanone to methyl acrylate is 1:1;H2O2 and Fe SO4 constitute Fenton reagent that the molar ratio of H2O2 and Fe SO4 is 2:1;the molar amount of cyclohexanone determined to be 10 times;under the condition of ice salt bath(-5 ?)for 6 h;The hydrolysis and acidification of the mixed branched polycarboxylate showed that the concentration of sodium hydroxide had a great influence on the yield of the mixed branched polycarboxylate.Phosphoric acid is more stable and safe in the electrolyte than acidification of sulfuric acid.The mixed branched polybasic ammonium carboxylate was prepared as 20% ethylene glycol solution.The flash voltage of the solution was 402 V,the oxidation efficiency was 1.2 V/s,the electrical conductivity(30 ?)was 2.68 ms/cm,thewater content was 3.24%,and the p H was 6~7.Five kinds of low temperature electrolytes with different specifications were prepared by using 20% branched polycarboxylic acid ammonium salt as solute.The degree of esterification of the electrolyte,encapsulation of water molecules in the electrolyte and the similar compatibility of the solvent has a great influence on the performance of the electrolyte.The experimental results show that the water content in the high-pressure electrolyte should be less than 5%,and the presence of small molecules such as citric acid in the high-pressure electrolyte may cause the flashover voltage of the electrolyte to be unstable.The way in which the electrolyte is stably present at-40 ? can be divided into two types:(1)increasing the conductivity of the electrolyte to a temperature greater than 2.5ms/cm while the flashover voltage of the electrolyte is constant;(2)using auxiliary solvent lowers the freezing point of the electrolyte while maintaining the electrolyte conductivity greater than 1.8 ms/cm.Five kinds of electrolytes were prepared that #HLW112 electrolyte was applied to 400V470 u F-35*50 series electrolytic capacitors with experimented at 120 Hz at 85 ? for 2000 h.The experimental results show that the electrolytic capacitor prepared by the electrolyte can effectively increase the capacitor capacity value by 1 to 3%,the loss value is less than6%,and the leakage current value is stable that the test value does not exceed 90 u A after2000 h.The results show that the electrolyte containing the branched polybasic ammonium carboxylate can be used in a low temperature environment and has great temperature properties and extreme foil similarity. |
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