A hydrogen remover, electrolyte, aluminum electrolytic capacitor and preparation method thereof

Abstract

The present invention discloses a dehydrogenating agent, an electrolyte, an aluminum electrolytic capacitor and a preparation method thereof. The preparation method comprises the following steps: (1) core package winding; (2) drying treatment; (3) electrolyte impregnation: immersing the core package of step (2) in an electrolyte for impregnation treatment, wherein the dehydrogenating agent in the electrolyte is composed of the following components by mass percentage: 30% to 45% sorbitol, 15% to 35% dihydroxybenzoic acid, 10% to 22% triethanolamine, 5% to 12% m-nitroacetophenone, 3% to 5% diphenyl phosphate, and 0.5% to 3% 2-carboxyethyl phosphate; (4) packaging step; (5) aging step. The aluminum electrolytic capacitor used in the photovoltaic inverter of the present invention has small performance parameter changes and good stability when used in extreme environments; a single electrolytic capacitor with high ripple resistance is used to reduce the number of electrolytic capacitors in parallel, thereby improving the overall reliability, and can greatly improve the reliability level of the photovoltaic inverter, meeting the requirements of the solar power generation system.

Description

Technical Field

[0001] The present invention relates to the technical field of capacitors, and in particular to a dehydrogenating agent, an electrolyte, an aluminum electrolytic capacitor and a preparation method thereof. Background Art

[0002] Under the global environmental protection trend, the new energy field will usher in rapid development; with the consumption of non-renewable energy and the increasing severity of environmental pollution, countries around the world pay more and more attention to energy conservation and emission reduction, and green energy has become the future direction of energy development. Governments have also increased their support for green energy, and the solar power generation industry has developed rapidly. As a new energy source, solar energy can provide clean and pollution-free energy for our lives. Since the current generated by the photovoltaic power generation system is direct current, but civil electricity is mainly alternating current, and solar power generation will eventually move towards grid-connected operation, this means that solar power generation must convert direct current into alternating current through an inverter to drive loads such as household appliances. Therefore, the inverter plays a vital role in the solar power generation system; in the solar power generation system, the service life of the photovoltaic panel is as long as 25 years, and the inverter can only be used for 5 to 10 years as a photovoltaic system. Therefore, the solar power generation system requires the life of the photovoltaic inverter system to be 25 years. For the passive component electrolytic capacitor, its negative electrode is the electrolyte, which will slowly dry up and fail as the use time increases. This will inevitably require the electrolytic capacitor industry to produce electrolytic capacitors with longer life to meet the requirements of photovoltaic inverters.

[0003] The life of a photovoltaic inverter is determined by the reliability of its components. Although semiconductor components can usually achieve this level of reliability, it may be a challenge for passive components, especially electrolytic capacitors. Improving the reliability of electrolytic capacitors has become one of the keys to improving the reliability of photovoltaic inverters. For medium and low power photovoltaic inverters, aluminum electrolytic capacitors are generally selected, especially for small power and off-grid photovoltaic inverters for households. The requirements for aluminum electrolytic capacitors are: high voltage (450-550V), high ripple resistance, charge and discharge resistance, long life, etc.

[0004] The long-life aluminum electrolytic capacitors on the market are currently 85°C and 5000 hours. The life and ripple resistance of electrolytic capacitors only meet the requirements of ordinary photovoltaic inverters for capacitors, but do not meet the requirements of solar power generation systems. Therefore, during the operation of the solar photovoltaic inverter, aluminum electrolytic capacitors become the most critical component restricting the service life of the inverter. The main reason is that the rated current of aluminum electrolytic capacitors cannot meet the requirements, and multiple electrolytic capacitors must be selected in parallel to obtain the required current value. Therefore, a single electrolytic capacitor with high ripple resistance is required to reduce the number of electrolytic capacitors in parallel and improve overall reliability.

[0005] For this reason, the industry has proposed electrolytes for aluminum electrolytic capacitors that are resistant to high temperatures and have a long life. For example, Chinese invention patent CN101483101A discloses a high-temperature 125°C long-life aluminum electrolytic capacitor, a manufacturing method thereof, and a dedicated electrolyte therefor. The capacitor is formed by winding a positive electrode foil, a negative electrode foil, electrolytic paper and a lead wire together to form the capacitor core package. After the core package is impregnated with the electrolyte, it is placed in the aluminum shell and sealed with the rubber plug. The components of the electrolyte include 85 to 88 parts of solvent, 5.5 to 11 parts of solute, 1 to 1.5 parts of additive and 3 to 5 parts of high-temperature stabilizer. The solvent is at least one of ethylene glycol, diethylene glycol and polyethylene glycol; the solute is at least one of boric acid, ammonium adipate, 1,7-ammonium sebacate, ammonium sebacate, ammonium benzoate and dodecanedioic acid; the additive is at least one of polyvinyl alcohol, ammonium hypophosphite, ammonium dihydrogen phosphate, p-nitrobenzoic acid and p-nitrobenzyl alcohol; and the high-temperature stabilizer is mannitol. For example, Chinese invention patent CN105513801A discloses an electrolyte for high-temperature resistant, ripple-resistant and long-life aluminum electrolytic capacitors and a preparation method thereof. The electrolyte is composed of the following raw materials in parts by weight: 4-6 parts of ammonium sebacate, 1.5-2.5 parts of ammonium pentaborate, 0.8-1.2 parts of mannitol, 10-14 parts of branched carboxylic acid, 16-20 parts of flash enhancer, 0.2-0.4 parts of organic phosphoric acid, 2.5-3.5 parts of o-nitroanisole, 0.2-0.3 parts of ammonium hypophosphite, and 45-70 parts of ethylene glycol.

[0006] Since the operating frequency of photovoltaic inverters is relatively high, large ripple and harmonic currents are generated, and the capacitors heat up seriously. At the same time, the operating environment conditions of photovoltaic equipment are harsh, and it works under high temperature for a long time, which causes the electrolyte to dry up and fail. Even after using the high-temperature resistant and long-life electrolytes of the above two prior arts, there is still a large change in resistivity with temperature, resulting in a significant increase in capacitor losses. When working at high temperature and high pressure, the leakage current is relatively large, resulting in poor ripple current resistance performance, which shortens the service life of the capacitor. Summary of the invention

[0007] In order to make up for the defects of the prior art, the present invention provides a hydrogen remover, an electrolyte, an aluminum electrolytic capacitor and a preparation method thereof.

[0008] The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0009] In a first aspect, the present invention provides a method for preparing an aluminum electrolytic capacitor for a photovoltaic inverter, comprising the following steps:

[0010] (1) Core package winding: insert electrolytic paper between the anode foil and the cathode foil and wind them into a core package;

[0011] (2) Drying: baking and drying the wound core package;

[0012] (3) electrolyte impregnation: immersing the core package of step (2) in an electrolyte for impregnation treatment, wherein the electrolyte is composed of the following components by mass percentage: 45% to 65% of a main solvent, 8% to 15% of an auxiliary solvent, 15% to 25% of a solute, 5% to 15% of an additive, and 0.5% to 2% of a hydrogen remover;

[0013] The hydrogen remover is composed of the following components by mass percentage: 30% to 45% of sorbitol, 15% to 35% of dihydroxybenzoic acid, 10% to 22% of triethanolamine, 5% to 12% of m-nitroacetophenone, 3% to 5% of diphenyl phosphate, and 0.5% to 3% of 2-carboxyethyl phosphoric acid;

[0014] (4) packaging step;

[0015] (5) Aging step.

[0016] In a second aspect, the present invention further provides an aluminum electrolytic capacitor for a photovoltaic inverter, which is prepared by the above-mentioned preparation method.

[0017] In a third aspect, the present invention provides a hydrogen remover, which is composed of the following components in percentage by mass: 30% to 45% sorbitol, 15% to 35% dihydroxybenzoic acid, 10% to 22% triethanolamine, 5% to 12% m-nitroacetophenone, 3% to 5% diphenyl phosphate, and 0.8% to 3% 2-carboxyethyl phosphoric acid.

[0018] In a fourth aspect, the present invention further provides an electrolyte, which is composed of the following components in mass percentage: 45% to 65% of a main solvent, 8% to 15% of an auxiliary solvent, 15% to 25% of a solute, 5% to 15% of an additive, and 0.5% to 2% of the above-mentioned hydrogen scavenger. The main solvent is composed of the following components by mass percentage: 40% to 55% of ethylene glycol, 20% to 35% of polypropylene alcohol, 10% to 20% of diethylene glycol monobutyl ether, and 5% to 9% of polyvinyl alcohol; the solute is composed of the following components by mass percentage: 35% to 55% of ammonium adipate, 15% to 30% of alkyl ammonium sebacate, 8% to 18% of butyl ammonium suberate, 3% to 10% of triammonium citrate, 1% to 5% of diammonium dihydrogen phosphate, and 0.8% to 3% of tetradecyl diacid; the additive is composed of the following components by mass percentage: 50% to 60% of dimethylamine, 15% to 25% of ammonium hypophosphite, 5% to 15% of mannitol, 3% to 10% of tributyl phosphate, and 1% to 5% of monobutyl phosphate.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The aluminum electrolytic capacitor used in the photovoltaic inverter of the present invention can effectively prevent the bottom of the capacitor from bulging and causing product failure when the capacitor works under large ripple conditions; and effectively inhibit the increase of the equivalent series resistance of the working electrolyte, which will generate greater heat and cause greater volatilization of the electrolyte, resulting in a significant increase in capacitor loss, which is beneficial to improving the ripple current resistance of the product; the performance parameters used in extreme environments have little change, and the product has good stability at 105° C. and a service life of 5000 hours; a single electrolytic capacitor with high ripple resistance is used to reduce the number of electrolytic capacitors in parallel, improve the overall reliability, and can greatly improve the reliability level of the photovoltaic inverter, meeting the requirements of the solar power generation system. DETAILED DESCRIPTION

[0021] As described in the background technology above, due to the high operating frequency of photovoltaic inverters, large ripple and harmonic currents are generated, and the capacitors heat up seriously. At the same time, the operating environment conditions of photovoltaic equipment are harsh, and it works under high temperature for a long time, which causes the electrolyte to dry up and fail. There is also a large change in resistivity with temperature, which causes a significant increase in capacitor losses. When working at high temperature and high pressure, the leakage current is relatively large, resulting in poor ripple current resistance performance and a short service life of the capacitor.

[0022] To this end, the inventors have proposed a dehydrogenating agent, an electrolyte, an aluminum electrolytic capacitor and a preparation method thereof to solve the above technical problems.

[0023] A method for preparing an aluminum electrolytic capacitor for a photovoltaic inverter comprises the following steps:

[0024] (1) Core package winding: insert electrolytic paper between the anode foil and the cathode foil and wind them into a core package;

[0025] (2) Drying: baking and drying the wound core package;

[0026] (3) electrolyte impregnation: immersing the core package of step (2) in an electrolyte for impregnation treatment, wherein the electrolyte is composed of the following components by mass percentage: 45% to 65% of a main solvent, 8% to 15% of an auxiliary solvent, 15% to 25% of a solute, 5% to 15% of an additive, and 0.5% to 2% of a hydrogen remover;

[0027] (4) packaging step;

[0028] (5) Aging step.

[0029] The choice of solvents: ethylene glycol, polypropylene alcohol, diethylene glycol monobutyl ether, and adding polyvinyl alcohol, so that its characteristics can significantly improve the oxidation efficiency and increase the flash voltage without affecting the conductivity of the electrolyte. At the same time, the auxiliary solvent benzyl alcohol is added to form an interface between it and the main solvent, effectively improve the activity of the molecular groups in the solvent, and improve the conductivity; polyethylene glycol is also added as an auxiliary solvent to increase its boiling point and reduce the vapor pressure, thereby greatly reducing the volatilization rate of the electrolyte, and it will not decompose due to the harsh environment, thereby increasing the service life. Specifically, in the electrolyte, the main solvent is composed of the following components by mass percentage: ethylene glycol 40% to 55%, polypropylene alcohol 20% to 35%, diethylene glycol monobutyl ether 10% to 20%, polyvinyl alcohol 5% to 9%. The auxiliary solvent is composed of the following components by weight percentage: polyethylene glycol 25 to 35% and benzyl alcohol 65 to 75%.

[0030] Selection of solutes: ammonium adipate, alkyl ammonium sebacate, butyl ammonium suberate, triammonium citrate, diammonium phosphate. Adding tetradecyl diacid can effectively inhibit the increase of equivalent series resistance of the working electrolyte, which will generate greater heat and cause greater volatilization of the electrolyte, resulting in a significant increase in capacitor loss, which is beneficial to improving the ripple current resistance of the product. Specifically, in the electrolyte, the solute is composed of the following components by mass percentage: 35% to 55% of ammonium adipate, 15% to 30% of alkyl ammonium sebacate, 8% to 18% of butyl ammonium suberate, 3% to 10% of triammonium citrate, 1% to 5% of diammonium phosphate and 0.8% to 3% of tetradecyl diacid.

[0031] Selection of additives: dimethylamine, ammonium hypophosphite, mannitol, tributyl phosphate, and then add an appropriate amount of monobutyl phosphate to ensure sufficient pressure resistance under high conductivity, and control the change of resistivity with temperature and increase of leakage current. Specifically, in the electrolyte, the additives are composed of the following components by mass percentage: 50% to 60% of dimethylamine, 15% to 25% of ammonium hypophosphite, 5% to 15% of mannitol, 3% to 10% of tributyl phosphate and 1% to 5% of monobutyl phosphate.

[0032] In the prior art, the dehydrogenating agent is generally one or more of resorcinol, p-nitrobenzoic acid, p-nitrobenzyl alcohol, m-nitroacetophenone, p-nitrophenol, o-nitroanisole, p-benzoquinone dinitrobenzene and 2,4-dinitrophenol; however, when used, these dehydrogenating agents and additives cannot be completely dissolved, and cannot inhibit the precipitation of hydrogen and the generation of water during the working process. In the present invention, the selection of dehydrogenating agents: sorbitol, dihydroxybenzoic acid, triethanolamine, m-nitroacetophenone, and additional addition of diphenyl phosphate and 2-carboxyethyl phosphoric acid to form a new mixed dehydrogenating agent can effectively reduce the increase in the internal pressure of the capacitor caused by the release of cathode hydrogen when the capacitor is working, reduce the precipitation of hydrogen and the generation of water during the working process, can withstand high surge voltage, and can more effectively prevent the capacitor from bulging at the bottom under large ripple conditions and causing product failure. Specifically, in the electrolyte, the hydrogen remover is composed of the following components by mass percentage: 30% to 45% sorbitol, 15% to 35% dihydroxybenzoic acid, 10% to 22% triethanolamine, 5% to 12% m-nitroacetophenone, 3% to 5% diphenyl phosphate, and 0.5% to 3% 2-carboxyethyl phosphoric acid.

[0033] The electrolytic paper is a double-layer paper composed of insulating wood pulp fiber and hemp fiber. The loss of the capacitor is related to the permeability coefficient of the electrolytic paper. Through the study of the characteristics of the fiber cell cavity and the electrolyte prepared in this case, the fiber raw materials with superior performance are selected. The present invention selects double-layer paper: insulating wood pulp fiber + hemp fiber to improve the liquid absorption effect of the fiber, so that the electrolytic paper has good permeability, ensuring the low loss performance of the electrolytic capacitor and good voltage resistance consistency.

[0034] Impregnation is an important production process in the production process of aluminum electrolytic capacitors. The quality of the capacitor core impregnation will directly affect the quality of the capacitor. The inventors have studied the impregnation process of aluminum electrolytic capacitors and its process requirements, improved the impregnation method, and improved the impregnation efficiency. The impregnation steps are: using a hydraulic cylinder to immerse the baked core package into the electrolyte for impregnation. The impregnation process is: the impregnation temperature is controlled at 55-65°C, the vacuum is maintained for 30-50 minutes, the pressurized pressure is 1±0.2Mpa, the pressure is maintained for 140-160 minutes, and the cycle is repeated 3-5 times to fully impregnate the electrolyte into the electrolytic paper, which has good impregnation properties and improves product performance.

[0035] The aluminum electrolytic capacitor used in the photovoltaic inverter of the present invention can effectively prevent the bottom of the capacitor from bulging and causing product failure when the capacitor works under large ripple conditions; and effectively inhibit the increase of the equivalent series resistance of the working electrolyte, which will generate greater heat and cause greater volatilization of the electrolyte, resulting in a significant increase in capacitor loss, which is beneficial to improving the ripple current resistance of the product; the performance parameters used in extreme environments have little change, and the product has good stability at 105° C. and a service life of 5000 hours; a single electrolytic capacitor with high ripple resistance is used to reduce the number of electrolytic capacitors in parallel, improve the overall reliability, and can greatly improve the reliability level of the photovoltaic inverter, meeting the requirements of the solar power generation system.

[0036] The raw materials and equipment used in the present invention, unless otherwise specified, are all commonly used raw materials and equipment in the art; the methods used in the present invention, unless otherwise specified, are all conventional methods in the art.

[0037] Unless otherwise specified, the meanings of the terms in this specification are the same as those generally understood by those skilled in the art. However, if there is any conflict, the definitions in this specification shall prevail.

[0038] As used herein, "includes," "comprising," "including," "containing," "having," or other variations are intended to encompass non-exclusive inclusions, and no distinction is made between these terms. The term "comprising" means that other steps and ingredients that do not affect the end result may be added. The term "comprising" also includes the terms "consisting of" and "consisting essentially of." The compositions and methods / processes of the present invention comprise, consist of, and consist essentially of the essential elements and limitations described herein, as well as any additional or optional ingredients, components, steps, or limitations described herein.

[0039] All numerical values ​​or expressions used in the specification and claims relating to component amounts, process conditions, etc. should be understood to be modified by "about" in all cases. All ranges relating to the same component or property include endpoints, which can be independently combined. Since these ranges are continuous, they include every numerical value between the minimum and maximum values. It should also be understood that any numerical range cited in the application is expected to include all subranges within the range.

[0040] The present invention is described in detail below with reference to the examples. The examples are only preferred embodiments of the present invention and are not intended to limit the present invention.

[0041] Example 1

[0042] A method for preparing an aluminum electrolytic capacitor for a photovoltaic inverter comprises the following steps:

[0043] (1) Core package winding: Electrolytic paper is inserted between the anode foil and the cathode foil and wound into a core package; wherein the electrolytic paper is a double-layer paper composed of insulating wood pulp fiber and hemp fiber;

[0044] (2) Drying: baking and drying the wound core package;

[0045] (3) electrolyte impregnation: immersing the core package of step (2) in an electrolyte for impregnation treatment;

[0046] The electrolyte is composed of the following components by mass percentage: 45% of main solvent, 15% of auxiliary solvent, 23% of solute, 15% of additive and 2% of hydrogen remover;

[0047] The main solvent is composed of the following components by mass percentage: 55% ethylene glycol, 20% polypropylene alcohol, 20% diethylene glycol monobutyl ether and 5% polyvinyl alcohol;

[0048] The auxiliary solvent is composed of the following components by weight percentage: 25% polyethylene glycol and 75% benzyl alcohol;

[0049] The solute is composed of the following components by mass percentage: 35% ammonium adipate, 30% alkyl ammonium sebacate, 18% butyl ammonium suberate, 10% triammonium citrate, 5% diammonium phosphate and 2% tetradecyl diacid;

[0050] The additive is composed of the following ingredients by mass percentage: 60% of dimethylamine, 17% of ammonium hypophosphite, 15% of mannitol, 3% of tributyl phosphate and 5% of monobutyl phosphate;

[0051] The hydrogen remover is composed of the following ingredients by mass percentage: 45% of sorbitol, 15% of dihydroxybenzoic acid, 22% of triethanolamine, 12% of m-nitroacetophenone, 4% of diphenyl phosphate and 2% of 2-carboxyethyl phosphoric acid;

[0052] Specifically, the impregnation step: using a hydraulic cylinder, immersing the baked core package into the electrolyte for impregnation, the impregnation process is: the impregnation temperature is controlled at 50°C, the vacuum is maintained for 40 minutes, the pressure is increased to 1±0.2Mpa, the pressure is maintained for 150 minutes, and the cycle is repeated 3 times;

[0053] (4) Packaging step: wrapping the core of step (3) into a shell and sealing with a rubber plug;

[0054] (5) Aging step.

[0055] The capacitor product prepared in Example 1 was subjected to a high temperature ripple life test and a surge voltage test. The test details are shown in Table 1 below.

[0056]

[0057] Example 2

[0058] A method for preparing an aluminum electrolytic capacitor for a photovoltaic inverter comprises the following steps:

[0059] (1) Core package winding: Electrolytic paper is inserted between the anode foil and the cathode foil and wound into a core package; wherein the electrolytic paper is a double-layer paper composed of insulating wood pulp fiber and hemp fiber;

[0060] (2) Drying: baking and drying the wound core package;

[0061] (3) electrolyte impregnation: immersing the core package of step (2) in an electrolyte for impregnation treatment;

[0062] The electrolyte is composed of the following components by mass percentage: 62% of main solvent, 12% of auxiliary solvent, 19.8% of solute, 5% of additive and 1.2% of hydrogen remover;

[0063] The main solvent is composed of the following components by mass percentage: 40% ethylene glycol, 32% polypropylene alcohol, 19% diethylene glycol monobutyl ether and 9% polyvinyl alcohol;

[0064] The auxiliary solvent is composed of the following components by weight percentage: 30% polyethylene glycol and 70% benzyl alcohol;

[0065] The solute is composed of the following components by mass percentage: 55% ammonium adipate, 27% alkyl ammonium sebacate, 8% butyl ammonium suberate, 3% triammonium citrate, 4% diammonium phosphate and 3% tetradecyl diacid;

[0066] The additive is composed of the following ingredients by mass percentage: 50% of dimethylamine, 25% of ammonium hypophosphite, 14% of mannitol, 10% of tributyl phosphate and 1% of monobutyl phosphate;

[0067] The hydrogen remover is composed of the following ingredients by mass percentage: 30% of sorbitol, 35% of dihydroxybenzoic acid, 22% of triethanolamine, 5% of m-nitroacetophenone, 5% of diphenyl phosphate and 3% of 2-carboxyethyl phosphoric acid;

[0068] Specifically, the impregnation step: using a hydraulic cylinder, immersing the baked core package into the electrolyte for impregnation, the impregnation process is: the impregnation temperature is controlled at 50°C, the vacuum is maintained for 40 minutes, the pressure is increased to 1±0.2Mpa, the pressure is maintained for 150 minutes, and the cycle is repeated 4 times;

[0069] (4) Packaging step: wrapping the core of step (3) into a shell and sealing with a rubber plug;

[0070] (5) Aging step.

[0071] The capacitor product prepared in Example 2 was subjected to a high temperature ripple life test and a surge voltage test. The test details are shown in Table 2 below.

[0072]

[0073] Example 3

[0074] A method for preparing an aluminum electrolytic capacitor for a photovoltaic inverter comprises the following steps:

[0075] (1) Core package winding: Electrolytic paper is inserted between the anode foil and the cathode foil and wound into a core package; wherein the electrolytic paper is a double-layer paper composed of insulating wood pulp fiber and hemp fiber;

[0076] (2) Drying: baking and drying the wound core package;

[0077] (3) electrolyte impregnation: immersing the core package of step (2) in an electrolyte for impregnation treatment;

[0078] The electrolyte is composed of the following components by mass percentage: 65% of main solvent, 8% of auxiliary solvent, 15% of solute, 11.5% of additive and 0.5% of hydrogen remover;

[0079] The main solvent is composed of the following components by mass percentage: 46% ethylene glycol, 35% polypropylene alcohol, 10% diethylene glycol monobutyl ether and 9% polyvinyl alcohol;

[0080] The auxiliary solvent is composed of the following components by weight percentage: 35% polyethylene glycol and 65% benzyl alcohol;

[0081] The solute is composed of the following components by mass percentage: 55% ammonium adipate, 15% alkyl ammonium sebacate, 17.2% butyl ammonium suberate, 10% triammonium citrate, 2% diammonium dihydrogen phosphate and 0.8% tetradecyl diacid;

[0082] The additive is composed of the following ingredients by mass percentage: 58% of dimethylamine, 24% of ammonium hypophosphite, 5% of mannitol, 9% of tributyl phosphate and 4% of monobutyl phosphate;

[0083] The hydrogen remover is composed of the following ingredients by mass percentage: 45% of sorbitol, 29.5% of dihydroxybenzoic acid, 10% of triethanolamine, 12% of m-nitroacetophenone, 3% of diphenyl phosphate and 0.5% of 2-carboxyethyl phosphoric acid;

[0084] Specifically, the impregnation step: using a hydraulic cylinder, immersing the baked core package into the electrolyte for impregnation, the impregnation process is: the impregnation temperature is controlled at 50°C, the vacuum is maintained for 40 minutes, the pressure is increased to 1±0.2Mpa, the pressure is maintained for 150 minutes, and the cycle is repeated 5 times;

[0085] (4) Packaging step: wrapping the core of step (3) into a shell and sealing with a rubber plug;

[0086] (5) Aging step.

[0087] The capacitor product prepared in Example 3 was subjected to a high temperature ripple life test and a surge voltage test. The test details are shown in Table 3 below.

[0088]

[0089] Comparative Example 1

[0090] The comparative example is substantially the same as Example 1, with the main difference being that the hydrogen remover is composed of the following components by mass percentage: 88% of resorcinol and 12% of m-nitroacetophenone.

[0091] The capacitor product prepared in Comparative Example 1 was subjected to a high temperature ripple life test and a surge voltage test. The test details are shown in Table 4 below.

[0092]

[0093] In comparative example 1, the dehydrogenating agent is composed of the following components by mass percentage: 88% resorcinol and 12% m-nitroacetophenone. It cannot be completely dissolved with the additive, and cannot effectively reduce the increase in the internal pressure of the capacitor caused by the release of cathode hydrogen when the capacitor is working, nor can it inhibit the precipitation of hydrogen and the generation of water during the working process. As a result, the loss value and leakage current of the capacitor are too large, and the stability is poor. After the ripple life test, not only the DF increase is obvious, the leakage current is large, but also the bottom of the aluminum shell is bulging and the element is dry; when subjected to high surge voltage, the capacity decreases significantly.

[0094] Comparative Example 2

[0095] The comparative example is substantially the same as Example 1, with the main difference being that the hydrogen remover is composed of the following components by mass percentage: 45% sorbitol, 15% dihydroxybenzoic acid, 22% triethanolamine and 18% m-nitroacetophenone.

[0096] The capacitor product prepared in Comparative Example 2 was subjected to a high temperature ripple life test and a surge voltage test. The test details are shown in Table 5 below.

[0097]

[0098] In comparative example 2, the dehydrogenating agent is composed of the following components by mass percentage: 45% sorbitol, 15% dihydroxybenzoic acid, 22% triethanolamine and 18% m-nitroacetophenone. It cannot be completely dissolved with the additives, and the existing solubility is poor, so that its conductivity is not large, and it cannot inhibit the precipitation of hydrogen and the generation of water during the working process. As a result, the loss value and leakage current of the capacitor are too large, and the stability is poor. After the ripple life test, not only the DF increase is obvious, the leakage current is large, but also the bottom of the aluminum shell is bulging; when subjected to high surge voltage, the capacity decreases significantly.

[0099] The above-mentioned embodiments merely express the implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the patent scope of the present invention. Any technical solution obtained in the form of equivalent replacement or equivalent transformation shall fall within the protection scope of the present invention.

Claims

1. A method for preparing an aluminum electrolytic capacitor for a photovoltaic inverter, characterized in that: It includes the following steps: (1) Core package winding: insert electrolytic paper between the anode foil and the cathode foil and wind them into a core package; (2) Drying: The wound core package is baked and dried; (3) electrolyte impregnation: immersing the core package of step (2) in an electrolyte for impregnation treatment, wherein the electrolyte is composed of the following components by mass percentage: 45% to 65% of a main solvent, 8% to 15% of an auxiliary solvent, 15% to 25% of a solute, 5% to 15% of an additive, and 0.5% to 2% of a hydrogen remover; The hydrogen remover is composed of the following components by mass percentage: 30% to 45% sorbitol, 15% to 35% dihydroxybenzoic acid, 10% to 22% triethanolamine, 5% to 12% m-nitroacetophenone, 3% to 5% diphenyl phosphate, and 0.5% to 3% 2-carboxyethyl phosphoric acid; (4) Packaging step; (5) Aging step; In the electrolyte, the main solvent is composed of the following components by mass percentage: 40% to 55% ethylene glycol, 20% to 35% polypropylene alcohol, 10% to 20% diethylene glycol monobutyl ether, and 5% to 9% polyvinyl alcohol; In the electrolyte, the solute is composed of the following components by mass percentage: 35% to 55% ammonium adipate, 15% to 30% alkyl ammonium sebacate, 8% to 18% butyl ammonium suberate, 3% to 10% triammonium citrate, 1% to 5% diammonium dihydrogen phosphate and 0.8% to 3% tetradecyl diacid; In the electrolyte, the additive is composed of the following components by mass percentage: 50% to 60% dimethylamine, 15% to 25% ammonium hypophosphite, 5% to 15% mannitol, 3% to 10% tributyl phosphate and 1% to 5% monobutyl phosphate; The auxiliary solvent is composed of the following components by weight: 25-35% polyethylene glycol and 65-75% benzyl alcohol.

2. The method for preparing an aluminum electrolytic capacitor for a photovoltaic inverter according to claim 1, characterized in that: The electrolytic paper is a double-layer paper composed of insulating wood pulp fibers and hemp fibers.

3. The method for preparing an aluminum electrolytic capacitor for a photovoltaic inverter according to claim 1, characterized in that: In step (3), a hydraulic cylinder is used to immerse the baked core package into the electrolyte for impregnation. The impregnation process is as follows: the impregnation temperature is controlled at 55-65°C, the vacuum is maintained for 30-50 minutes, the pressurization pressure is 1±0.2Mpa, the pressure is maintained for 140-160 minutes, and the cycle is repeated 3-5 times.

4. An aluminum electrolytic capacitor for a photovoltaic inverter, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 3.

5. A hydrogen scavenger, characterized in that: It is composed of the following ingredients by mass percentage: 30%-45% sorbitol, 15%-35% dihydroxybenzoic acid, 10%-22% triethanolamine, 5%-12% m-nitroacetophenone, 3%-5% diphenyl phosphate, and 0.5%-3% 2-carboxyethyl phosphoric acid.

6. An electrolyte, characterized in that: It is composed of the following components by mass percentage: 45% to 65% of the main solvent, 8% to 15% of the auxiliary solvent, 15% to 25% of the solute, 5% to 15% of the additive, and 0.5% to 3% of the hydrogen remover as claimed in claim 5; The main solvent is composed of the following components by mass percentage: 40%-55% of ethylene glycol, 20%-35% of polypropylene alcohol, 10%-20% of diethylene glycol monobutyl ether, and 5%-9% of polyvinyl alcohol; the solute is composed of the following components by mass percentage: 35%-55% of ammonium adipate, 15%-30% of alkyl ammonium sebacate, 8%-18% of butyl ammonium suberate, 3%-10% of triammonium citrate, 1%-5% of ammonium dihydrogen phosphate, and 0.8%-3% of tetradecyl diacid; the additive is composed of the following components by mass percentage: 50%-60% of dimethylamine, 15%-25% of ammonium hypophosphite, 5%-15% of mannitol, 3%-10% of tributyl phosphate, and 1%-5% of monobutyl phosphate; the auxiliary solvent is composed of the following components by weight percentage: 25%-35% of polyethylene glycol and 65%-75% of benzyl alcohol.

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