Electrolyte for high-conductance high-water-range temperature aluminum electrolytic capacitor and preparation method thereof

Abstract

The application relates to the technical field of electrolyte, and discloses an electrolyte for high-conductivity high-water-content wide-temperature-range aluminum electrolytic capacitors and a preparation method thereof, which comprises main solutes 5-20%, auxiliary solutes 0.5-5%, solvents 50-90% and additives 0.5-10% in percentage by mass. The electrolyte prepared by the application has a conductivity of 38 ms / cm, a water content of not less than 40%, and a flashover voltage of 210 V. The electrolyte of the application can effectively reduce the vapor pressure of the electrolyte, inhibit gas generation, reduce the internal pressure of the capacitor and improve the high-temperature performance of the electrolyte through the cooperation between raw materials. The electrolyte of the application has stable high-temperature performance, a wide use temperature range and high oxidation efficiency, and the aluminum electrolytic capacitor assembled by using the electrolyte can be reliably and continuously operated for more than 3000 hours under the environment of-40 DEG C to +105 DEG C.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electrolyte, and particularly relates to an electrolyte for high-conductivity high-water-system wide-temperature aluminum electrolytic capacitor and a preparation method thereof BACKGROUND

[0002] Aluminum electrolytic capacitor is one of the most important basic electronic components in electronic engineering. In addition to the functions of filtering, coupling and bypassing in electronic circuits, it also plays a special role in special circuits such as correction circuits, pump power supply circuits and alternating current motor starting circuits. Therefore, it has a wide range of applications in the fields of communication equipment, audio-visual systems, household appliances and electronic instruments and meters. With the rapid development of electronic technology, aluminum electrolytic capacitors are rapidly developing towards small size, wide temperature and long service life.

[0003] The traditional aqueous electrolyte adopts an ammonium adipate-ethylene glycol / water system. However, the use temperature range of this electrolyte is very limited, usually -40℃ to +85℃, and the hydration reaction occurs in the electrolyte, which seriously damages the aluminum oxide film on the anode. The electrolyte generates water vapor and hydrogen gas at high temperatures, resulting in extremely unstable high-temperature performance of the electrolyte, which is prone to bottom swelling failure and explosion valve opening at high temperatures. SUMMARY

[0004] The purpose of the present application is to overcome the above technical deficiencies and provide an electrolyte for high-conductivity high-water-system wide-temperature aluminum electrolytic capacitor and a preparation method thereof.

[0005] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0006] An electrolyte for high-conductivity high-water-system wide-temperature aluminum electrolytic capacitor, comprising the following components in mass percentage:

[0007]

[0008]

[0009] Preferably, the electrolyte comprises the following components in mass percentage:

[0010]

[0011] Preferably, the main solute is one or more of ammonium maleate, ammonium adipate, ammonium benzoate, phthalic acid, ammonium succinate, straight-chain ammonium dicarboxylate and branched-chain ammonium dicarboxylate.

[0012] Preferably, the auxiliary solute is one or more of boric acid, ammonium formate, ammonium pentaborate, straight-chain dicarboxylic acid and branched-chain dicarboxylic acid.

[0013] Preferably, the solvent is one or more of water and ethylene glycol, DMF, gamma-butyrolactone, propylene glycol, diethylene glycol.

[0014] Preferably, the additive includes an anti-hydrating agent, a hydrogen-eliminating agent, an anti-corrosion agent, a leakage current inhibitor and an additive.

[0015] Preferably, the anti-hydrating agent is one or more of phosphoric acid, hypophosphorous acid, ammonium phosphate, ammonium dihydrogen phosphate; the hydrogen-eliminating agent is one or more of p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, p-nitrophenol, p-nitrobenzyl alcohol; the anti-corrosion agent is one or more of EDTA, nitrilotriacetic acid, 8-hydroxyquinoline, phosphotungstic acid; the leakage current inhibitor is one or more of silicotungstic acid, molybdic acid, 3,5-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid.

[0016] Preferably, the additive includes adipoyl diamine and a mixture of adipic acid and ethylene glycol prepared at a molar ratio of 1:1-3.

[0017] Preferably, the method for preparing the additive from adipic acid and ethylene glycol comprises the following steps: adding adipic acid and ethylene glycol into a three-necked flask, heating at 130-150℃ for 1-3h, then introducing nitrogen, increasing the temperature to 160-180℃, heating for 1-3h, further increasing the temperature to 205-225℃, stopping the nitrogen, drawing negative pressure of 5-25Kp, heating for 1-3h, and obtaining the additive after cooling.

[0018] The present application also protects a method for preparing the electrolyte for the high-conductivity high-water-system wide-temperature aluminum electrolytic capacitor, comprising the following steps:

[0019] (1) mixing the solvent and the solute, and heating at 100-125℃ for 60-100min;

[0020] (2) reducing the temperature to 75-90℃, then adding the anti-hydrating agent, the hydrogen-eliminating agent, the anti-corrosion agent, the leakage current inhibitor and the additive, and heating and stirring for 10-30min;

[0021] (3) reducing the temperature to room temperature, adding water, stirring until uniform, and obtaining the electrolyte.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] The electrolyte contains an anti-hydrating agent, a hydrogen-eliminating agent, an anti-corrosion agent, a leakage current inhibitor and an additive. The anti-hydrating agent can prevent or inhibit the reaction of water molecules in the electrolyte medium with the aluminum oxide film, the mechanism of which is to form a protective film on the surface of the aluminum oxide film to prevent the hydration reaction. The hydrogen-eliminating agent can effectively inhibit or eliminate the generation of hydrogen and gas. The anti-corrosion agent can react with Cl -The precipitate or complex is formed to prevent the reaction of chloride ions with the aluminum oxide film and the electrode. The leakage current inhibitor can inhibit the leakage current from rising. The additive adipic acid diamide can inhibit the solute amide reaction to generate water. Another additive PEA is a mixture of adipic acid and ethylene glycol in a molar ratio of 1:1-3. The synthesized PEA is a hydrophilic polymer, which is dissolved in the electrolyte to fix water molecules, prevent water and other harmful substances from directly contacting the medium film, and effectively reduce the vapor pressure of the electrolyte. The electrolyte of the application can effectively reduce the vapor pressure of the electrolyte by the cooperation of raw materials, inhibit the generation of gas, reduce the internal pressure of the capacitor, and improve the high-temperature performance of the electrolyte. The electrolyte of the application has stable high-temperature performance, a wide use temperature range, and high oxidation efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 Simple device for testing flashover voltage. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and do not limit the present application.

[0026] It should be particularly emphasized that, unless otherwise specified, the raw materials or reagents in the present application are purchased through commercial channels.

[0027] Example 1

[0028] A kind of high conductivity high water system wide temperature aluminum electrolytic capacitor electrolyte, by the following components according to mass percentage: ammonium maleate 10%, boric acid 3%, ethylene glycol 33.7%, water 45%, PEA 5%, phosphoric acid 1.5%, ammonium hypophosphite 0.5%, p-nitrobenzoic acid 1%, 8-hydroxyquinoline 0.1%, 3, 5-dihydroxybenzoic acid 0.1%, adipic acid diamide 0.1%.

[0029] The preparation method of the electrolyte comprises the following steps:

[0030] (1) mix ethylene glycol, ammonium maleate and boric acid, and then heat at 115℃ for 70 min;

[0031] (2) reduce the temperature to 80℃, then add the water inhibitor phosphoric acid and ammonium hypophosphite, the hydrogen inhibitor 3, 5-dihydroxybenzoic acid and p-nitrobenzoic acid, the corrosion inhibitor 8-hydroxyquinoline, the leakage current inhibitor 3, 5-dihydroxybenzoic acid, and the additives adipic acid diamide and PEA, and heat and stir for 10 min;

[0032] (3) reduce the temperature to room temperature, add water, and stir until uniform to obtain the electrolyte.

[0033] The preparation method of the additive PEA is: adipic acid and ethylene glycol are added into a three-necked flask in a molar ratio of 1:2, and heated at 140℃ for 2h, then nitrogen is introduced, the temperature is raised to 170℃, and heated for 2h, then the temperature is raised to 215℃, the nitrogen is closed, and negative pressure of 15Kp is extracted, and heated for 2h, and the additive is obtained after cooling.

[0034] Example 2

[0035] An electrolyte for high-conductivity high-water-system wide-temperature aluminum electrolytic capacitor, made of the following components in mass percentage: ammonium adipate 12%, ammonium formate 3%, ethylene glycol 35.3%, water 40%, PEA 3%, phosphoric acid 2%, ammonium hypophosphite 0.5%, p-nitrobenzoic acid 3%, 8-hydroxyquinoline 0.1%, 3,5-dihydroxybenzoic acid 0.1%, adipic diamide 1%.

[0036] The preparation method of the electrolyte comprises the following steps:

[0037] (1) ethylene glycol, ammonium adipate, and ammonium formate are mixed and heated at 125℃ for 70min;

[0038] (2) the temperature is lowered to 90℃, then the anti-hydration agents phosphoric acid and ammonium hypophosphite, the hydrogen elimination agent p-nitrobenzoic acid, the corrosion inhibitor 8-hydroxyquinoline, the leakage current inhibitor 3,5-dihydroxybenzoic acid, and the additives adipic diamide and PEA are added, and heated and stirred for 20min;

[0039] (3) the temperature is lowered to room temperature, water is added, and stirred uniformly to obtain the electrolyte.

[0040] The preparation method of the additive PEA is: adipic acid and ethylene glycol are added into a three-necked flask in a molar ratio of 1:1.5, and heated at 135℃ for 2h, then nitrogen is introduced, the temperature is raised to 165℃, and heated for 2h, then the temperature is raised to 215℃, the nitrogen is closed, and negative pressure of 15Kp is extracted, and heated for 2h, and the additive is obtained after cooling.

[0041] Example 3

[0042] An electrolyte for high-conductivity high-water-system wide-temperature aluminum electrolytic capacitor, made of the following components in mass percentage: ammonium adipate 12%, ammonium formate 3%, ethylene glycol 35.3%, water 40%, PEA 3%, phosphoric acid 2%, ammonium hypophosphite 0.5%, p-nitrobenzoic acid 3%, 8-hydroxyquinoline 0.1%, 3,5-dihydroxybenzoic acid 0.1%, adipic diamide 1%.

[0043] The preparation method of the electrolyte comprises the following steps:

[0044] (1) ethylene glycol, DMF, ammonium adipate, and pentaborate are mixed and heated at 100℃ for 100min;

[0045] (2) the temperature is reduced to 85℃, then the anti-hydrating agent ammonium dihydrogen phosphate, the hydrogen-eliminating agent p-nitrophenol, the anti-corrosion agent phosphotungstic acid, the leakage current inhibitor molybdic acid, and the additives adipoyldiamine and PEA are added, and the temperature is kept for 30min with stirring;

[0046] (3) the temperature is reduced to room temperature, water is added, and the electrolyte is obtained after uniform stirring.

[0047] The preparation method of the additive PEA is as follows: adipic acid and ethylene glycol are added into a three-necked flask in a molar ratio of 1:2.5, and the temperature is kept at 130℃ for 3h, then nitrogen is introduced, the temperature is raised to 160℃, and kept for 3h, then the temperature is raised to 215℃, the nitrogen is closed, and negative pressure of 15Kp is extracted, and the temperature is kept for 2h, and the additive is obtained after cooling.

[0048] Example 4

[0049] An electrolyte for high-conductance high-water-system wide-temperature aluminum electrolytic capacitor is prepared from the following components in percentage by mass: ammonium adipate 10%, boric acid 5%, ethylene glycol 15%, water 50%, γ-butyrolactone 14.5%, PEA 2%, ammonium phosphate 1%, p-nitrobenzyl alcohol 1%, 8-hydroxyquinoline 0.5%, silicotungstic acid 0.5%, and adipoyldiamine 0.5%.

[0050] The preparation method of the electrolyte comprises the following steps:

[0051] (1) ethylene glycol, γ-butyrolactone, ammonium adipate, and boric acid are mixed, and the temperature is kept at 115℃ for 60min;

[0052] (2) the temperature is reduced to 90℃, then the anti-hydrating agent ammonium phosphate, the hydrogen-eliminating agent p-nitrobenzyl alcohol, the anti-corrosion agent 8-hydroxyquinoline, the leakage current inhibitor silicotungstic acid, and the additives adipoyldiamine and PEA are added, and the temperature is kept for 30min with stirring;

[0053] (3) the temperature is reduced to room temperature, water is added, and the electrolyte is obtained after uniform stirring.

[0054] The preparation method of the additive PEA is as follows: adipic acid and ethylene glycol are added into a three-necked flask in a molar ratio of 1:1, and the temperature is kept at 145℃ for 2h, then nitrogen is introduced, the temperature is raised to 180℃, and kept for 2h, then the temperature is raised to 205℃, the nitrogen is closed, and negative pressure of 15Kp is extracted, and the temperature is kept for 2h, and the additive is obtained after cooling.

[0055] Example 5

[0056] An electrolyte for high-conductance high-water-system wide-temperature aluminum electrolytic capacitor is prepared from the following components in percentage by mass: ammonium maleate 12%, ammonium formate 3%, ethylene glycol 20%, water 40%, DMF 19.3%, PEA 3%, phosphoric acid 1%, p-nitrobenzoic acid 1%, 8-hydroxyquinoline 0.1%, 3,5-dihydroxybenzoic acid 0.1%, adipic diamide 0.5%.

[0057] A preparation method of the electrolyte comprises the following steps:

[0058] (1) mixing ethylene glycol, DMF, ammonium maleate and ammonium formate and then keeping at 125 ℃ for 70 min;

[0059] (2) reducing the temperature to 85 ℃, then adding the hydration-preventing agent phosphoric acid, the hydrogen-consuming agent p-nitrobenzoic acid, the corrosion-preventing agent 8-hydroxyquinoline, the leakage current inhibitor 3,5-dihydroxybenzoic acid, the additive adipic diamide and PEA, and keeping at 85 ℃ for 15 min;

[0060] (3) reducing the temperature to room temperature, adding water, and stirring uniformly to obtain the electrolyte.

[0061] A preparation method of the additive PEA is as follows: adipic acid and ethylene glycol are added into a three-necked flask in a molar ratio of 1:3, and kept at 150 ℃ for 2 h; then nitrogen is introduced, the temperature is raised to 160 ℃, and kept at 160 ℃ for 2 h; then the temperature is raised to 210 ℃, the nitrogen is stopped, and the negative pressure is extracted to 15 Kp, and kept at 210 ℃ for 2 h; and after cooling, the additive is obtained.

[0062] Comparative Example 1

[0063] An electrolyte for high-conductance high-water-system wide-temperature aluminum electrolytic capacitor is prepared from the following components in percentage by mass: ammonium maleate 12%, ammonium formate 3%, ethylene glycol 20%, water 40%, DMF 19.3%, PEA 3%, phosphoric acid 1%, p-nitrobenzoic acid 1%, 8-hydroxyquinoline 0.1%, 3,5-dihydroxybenzoic acid 0.1%, adipic diamide 0.5%.

[0064] A preparation method of the electrolyte comprises the following steps:

[0065] (1) mixing ethylene glycol, DMF, ammonium maleate and ammonium formate and then keeping at 125 ℃ for 70 min;

[0066] (2) reducing the temperature to 85 ℃, then adding the hydration-preventing agent phosphoric acid and ammonium hypophosphite, the hydrogen-consuming agent 3,5-dihydroxybenzoic acid and p-nitrobenzoic acid, the corrosion-preventing agent 8-hydroxyquinoline, the leakage current inhibitor 3,5-dihydroxybenzoic acid, and the additive adipic diamide, and keeping at 85 ℃ for 15 min;

[0067] (3) reducing the temperature to room temperature, adding water, and stirring uniformly to obtain the electrolyte.

[0068] The performance test of the electrolyte prepared according to Examples 1-5 and Comparative Example 1 is shown in Table 1:

[0069] Measurement of conductivity: The conductivity of the working electrolyte was measured by using a DDS-307A conductivity tester. The temperature of the working electrolyte was kept constant at 25°C before the measurement.

[0070] Measurement of flashover voltage: The flashover voltage of the working electrolyte was measured by using a single-channel aluminum foil TV characteristic / leakage current / electrolyte intelligent test system TV-1CH. The test conditions were as follows: using a 365V positive foil, test voltage 365V, boost current 2mA, test temperature 25°C, and delay time 60s. Figure 1 is a simple device for flashover voltage test. The initial flashover voltage A is recorded, and the voltage value at point A is the flashover voltage.

[0071] Table 1

[0072] Conductivity (ms / cm) Flame voltage (v) Example 1 38.0 210.1 Example 2 37.8 208.7 Example 3 36.4 211.5 Example 4 38.4 207.7 Example 5 39.6 215.7 Comparative Example 1 42.3 200.5

[0073] The aluminum electrolytic capacitor was prepared with a specification of 50v-220uf 8mm x 16mm. The method for preparing the aluminum electrolytic capacitor included the following steps:

[0074] Step one: The leads of the anode foil and the cathode foil were riveted on the anode foil and the cathode foil. The anode foil and the cathode foil were alternately arranged between the separator paper, and then wound into a capacitor core package by a winding machine, and finally fixed into shape.

[0075] Step two: The capacitor core package was saturated with electrolyte to saturate the paper separator layer and immerse each part of the corroded aluminum foil.

[0076] Step three: The immersed capacitor core package was sealed in an aluminum shell with a sealing rubber plug to obtain an aluminum electrolytic capacitor.

[0077] The aluminum electrolytic capacitor samples were aged at 85°C for 4h, and then the samples were subjected to a life load test at 105°C. Ten samples of the capacitors of each example or comparative example were put into the experiment to obtain the initial characteristics and life test results of the aluminum electrolytic capacitors. The time required for a 20% change in the capacity of the capacitors was recorded, and after removing the abnormal values, the mean value was calculated. The results are shown in Table 2.

[0078] Table 2 is the performance of the aluminum electrolytic capacitor with a specification of 50v-220uf 8mm x 16mm.

[0079]

[0080] As shown in Table 1 and Table 2, the electrolyte of the present application has a conductivity of up to 38 ms / cm, a water content of not less than 40%, and a flash voltage of up to 210 V. The electrolyte of the present application can effectively reduce the vapor pressure of the electrolyte, inhibit gas generation, and thus reduce the internal pressure of the capacitor and improve the high-temperature performance of the electrolyte, through the cooperation of raw materials. The electrolyte of the present application has stable high-temperature performance, a wide use temperature range, and high oxidation efficiency, and the aluminum electrolytic capacitor assembled therefrom can be reliably and continuously operated for more than 3000 h in an environment of -40℃ to +105℃.

[0081] The above merely describes the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art, according to the technical solutions and inventive concept of the present application, can make equivalent replacements or changes within the technical range disclosed by the present application, which should be encompassed in the protection scope of the present application.

Claims

1. An electrolyte for a high- conductivity, high-water-range, temperature-stable aluminum electrolytic capacitor, characterized by comprising: By mass percentage, comprising the following components: Main solute 5~20% Auxiliary solute 0.5~5% Solvent 50~90% Additive 0.5~10%; The main solute is one or more of ammonium maleate, ammonium adipate, ammonium benzoate, phthalic acid, ammonium succinate; The auxiliary solute is one or more of boric acid, ammonium formate, ammonium pentaborate; The additive includes hydration-preventing agent, hydrogen-eliminating agent, corrosion-preventing agent, leakage current inhibitor and additive; The additive includes adipoyl diamine and a mixture made from adipic acid and ethylene glycol in a molar ratio of 1:1-3; The method for preparing the additive from adipic acid and ethylene glycol is: adipic acid and ethylene glycol are added into a three-necked flask, and kept at 130-150℃ for 1-3h, then nitrogen is introduced, the temperature is raised to 160-180℃, and kept for 1-3h, then the temperature is raised to 205-225℃, nitrogen is closed, negative pressure of 5-25Kp is extracted, and kept for 1-3h, and the additive is obtained after cooling.

2. The electrolyte according to claim 1, characterized in that, By mass percentage, comprising the following components: Main solute 8~15% Auxiliary solute 1.5~3.5% Solvent 60~85% Additive 2.5~7.5%.

3. The electrolyte of claim 1, wherein The hydration-preventing agent is one or more of phosphoric acid, hypophosphorous acid, ammonium phosphate, ammonium dihydrogen phosphate; the hydrogen-eliminating agent is one or more of p-nitrobenzoic acid, 3,5-dinitrobenzoic acid, p-nitrophenol, p-nitrobenzyl alcohol; the corrosion-preventing agent is one or more of EDTA, nitrilotriacetic acid, 8-hydroxyquinoline, phosphotungstic acid; the leakage current inhibitor is one or more of silicotungstic acid, molybdic acid, 3,5-dihydroxybenzoic acid, 3,4-dihydroxybenzoic acid.

4. A process for the preparation of the electrolyte for high conductivity, high water range, temperature-stable aluminum electrolytic capacitors according to any one of claims 1 to 3, comprising the following steps: (1) the solvent and solute are mixed and kept at 100-125℃ for 60-100min; (2) the temperature is lowered to 75-90℃, then the hydration-preventing agent, hydrogen-eliminating agent, corrosion-preventing agent, leakage current inhibitor and additive are added, and kept for 10-30min with stirring; (3) the temperature is lowered to room temperature, water is added, and stirred until uniform, and the electrolyte is obtained.

Images