Electrolyte for middle-high voltage aluminum electrolytic capacitor and aluminum electrolytic capacitor

Abstract

The invention discloses an electrolyte for a middle-high voltage aluminum electrolytic capacitor and the aluminum electrolytic capacitor, and belongs to the technical field of electrochemistry, the electrolyte comprises a solute, a solvent and an additive, the solute comprises a cycloolefin carboxylic acid ammonium salt compound, the additive comprises an inorganic boron compound, and the structural formula of the cycloolefin carboxylic acid ammonium salt compound is shown in a formula (1) or a formula (2). A is a hydrogen atom or one of a hydrocarbon group, a carboxyl group and an ammonium carboxylate group containing 1-10 carbon atoms, and B is a hydrogen atom or one of a hydrocarbon group, a carboxyl group and an ammonium carboxylate group containing 1-10 carbon atoms; wherein B is a hydrogen atom or a hydrocarbyl group containing from 1 to 10 carbon atoms; the value of x + y is 0-30, the cycloolefin carboxylic acid ammonium salt compound and the inorganic boron compound are combined to serve as the electrolyte, the boron-containing compound serves as a retarding agent to prevent the cycloolefin carboxylic acid ammonium salt compound from being decomposed, and therefore the ideal electrolyte is formed.

Description

Technical Field

[0001] The present invention relates to the field of electrochemical technology, and in particular to an electrolyte for medium- and high-voltage aluminum electrolytic capacitors and an aluminum electrolytic capacitor. Background Art

[0002] Aluminum electrolytic capacitors are one of the basic components of electronic products and are widely used in the production of automotive electronics, frequency conversion technology, displays, chargers, electronic ballasts, switching power supplies, and energy-saving lamps. In recent years, the rapid development of electronic technology and the further improvement of the degree of integration have put forward higher requirements on the comprehensive performance of aluminum electrolytic capacitors, driving aluminum electrolytic capacitors to develop in the direction of high voltage, high capacitance, and long life.

[0003] Aluminum electrolytic capacitors are mainly composed of capacitor cores and working electrolytes. The working electrolyte plays a key role in the performance of aluminum electrolytic capacitors, determining the operating temperature range, rated voltage, loss factor, impedance, rated ripple current, and working life of the capacitors.

[0004] At present, the working electrolyte of medium and high voltage aluminum electrolytic capacitors is mostly a linear carboxylic acid ammonium salt + boric acid salt + ethylene glycol system. The more carbon atoms in the linear carboxylic acid salt, the higher the flash voltage, but its solubility decreases sharply with the increase of molecular weight. For example, the solubility of commonly used ammonium sebacate in ethylene glycol does not exceed 5%, and it is easy to crystallize at low temperatures, which restricts the working temperature range of the capacitor. Branched polycarboxylates have relatively high solubility in polysolvents, are not easy to crystallize at low temperatures, have a wide operating temperature range, and have high electrolyte conductivity. The prepared capacitors have strong withstand voltage and high ripple current resistance capabilities, but branched polycarboxylates have the disadvantages of high cost and insufficient flash voltage performance. For example, the flash voltage at a concentration of 5% is difficult to reach above 500V. In addition, other solutes that can be used as working electrolytes for medium and high voltage aluminum electrolytic capacitors include linear carboxylates such as ammonium azelaic acid, ammonium hydrogen azelaic acid, ammonium sebacate, ammonium dodecanedioate, as well as ammonium pentaborate and ammonium benzoate. However, each of them has certain disadvantages, such as ammonium dodecanedioate is not easy to obtain, ammonium pentaborate has a high conductivity, and ammonium benzoate is unstable at high temperatures. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an electrolyte for medium and high voltage aluminum electrolytic capacitors and an aluminum electrolytic capacitor, using a cycloolefin carboxylic acid ammonium salt compound as a solute and adding an inorganic boron compound as a buffer, and the resulting electrolyte is applied to capacitors and has higher thermal stability and long life. The specific technical solution is as follows:

[0006] An electrolyte for medium- and high-voltage aluminum electrolytic capacitors, comprising a solute, a solvent and an additive, wherein the solute comprises a cycloolefin carboxylic acid ammonium salt compound, and the additive comprises an inorganic boron compound, wherein the cycloolefin carboxylic acid ammonium salt compound has a structural formula as shown in formula (1) or formula (2):

[0007]

[0008] Wherein A is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, a carboxyl group, or an ammonium carboxylate group; wherein B is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms; x and y are integers, and the value of x+y is 0 to 30. Studies have shown that by adding a boron-containing compound as a retarder to the electrolyte, the decomposition of the cycloolefin carboxylate ammonium salt compound can be prevented in a high temperature environment, thereby improving the high temperature performance and life of the electrolyte.

[0009] The cycloolefin carboxylic acid ammonium salt can be obtained by reacting conjugated linoleic acid and its derivatives with an enophile compound through Diels-Alder reaction, followed by hydrolysis, purification and ammonia. The conjugated linoleic acid and its derivatives are selected from one of conjugated linoleic acid, conjugated linoleic acid methyl ester, conjugated linoleic acid ethyl ester, conjugated linoleic acid propyl ester, conjugated linoleic acid butyl ester, conjugated linoleic acid isopropyl ester, conjugated linoleic acid formamide and conjugated linoleic acid acetamide; the enophile compound is selected from one of acrylic acid and its derivatives, butenoic acid and its derivatives, pentenoic acid and its derivatives, methacrylic acid and its derivatives, maleic acid and its derivatives, maleic anhydride, citraconic acid and anhydride, and acrylonitrile.

[0010] Preferably, the cycloolefin carboxylate ammonium salt compound is selected from 4-hexyl-6-carboxylic acid ammonium-cyclohex-2-ene-1-octanoic acid ammonium, 4-hexyl-5,6-dicarboxylic acid ammonium-6 methyl-cyclohex-2-ene-1-octanoic acid ammonium, 4-hexyl-6-carboxylic acid ammonium-6 methyl-cyclohex-2-ene-1-octanoic acid ammonium, 6-propyl-1,3,5 tricarboxylic acid ammonium-cyclohex-2-ene and 4-hexyl-5-ethyl-6-carboxylic acid ammonium-cyclohex-2-ene-1-octanoic acid ammonium, 4-hexyl-5-butyl-6-carboxylic acid ammonium-cyclohex-2-ene-1-octanoic acid ammonium.

[0011] Preferably, the inorganic boron compound is selected from one or more of boric acid, ammonium diborate, ammonium pentaborate and boric acid esters.

[0012] Preferably, the amount of the cycloolefin carboxylic acid ammonium salt compound added is 0.10-30.00% of the total amount of the electrolyte, preferably 0.50-15.00% by mass.

[0013] Preferably, the inorganic boron compound is added in an amount of 1.00-10.00% of the total amount of the electrolyte, preferably 2.00-5.00%.

[0014] Preferably, the solvent accounts for 60-95% of the total amount of the electrolyte, and the solvent is selected from one or more of alcohols, alcohol ethers, amides, sulfones, sulfoxides and esters; preferably, the solvent is ethylene glycol or γ-butyrolactone.

[0015] Preferably, the additives further include one or more of a waterproofing agent, a hydrogen scavenger, a flash enhancer, an anti-corrosion additive and a leakage current inhibitor.

[0016] Preferably, the waterproofing mixture is selected from one or more of hypophosphorous acid, phosphorous acid, phosphoric acid and monoalkyl phosphate, or one or more of ammonia or amine salts of hypophosphorous acid, phosphorous acid, phosphoric acid and monoalkyl phosphate;

[0017] Preferably, the hydrogen remover is selected from one or more of p-nitrophenol, p-nitrobenzyl alcohol, o-nitroanisole and m-nitroacetophenone;

[0018] Preferably, the flash enhancer is selected from one or more of silica melt, polyvinyl alcohols, polyethylene glycols, polyvinyl alcohol borates, polyvinyl alcohol phosphates, polyvinyl pyrrolidone and mannitol;

[0019] The anti-corrosion additive is selected from one or more of nitrilotriacetic acid, EDTA, silver benzoate and 8-hydroxyquinoline;

[0020] The leakage current inhibitor is selected from one or more of phosphotungstic acid, molybdotungstic acid, 3,5-dihydroxybenzoic acid and strontium nitrate.

[0021] Preferably, the amount of the waterproof mixture added is 0.05-5.00% of the total amount of the electrolyte, preferably 0.10-3.00% by mass percentage;

[0022] Preferably, the amount of the hydrogen remover added is 0.10-15.00% of the total amount of the electrolyte, preferably 0.20-4.00% by mass percentage;

[0023] Preferably, the amount of the flash enhancer added is 0.20-15.00% of the total amount of the electrolyte, preferably 0.50-10.00% by mass;

[0024] Preferably, the amount of the anti-corrosion additive added is 0.01-5.00% of the total amount of the electrolyte, preferably 0.01-1.00% by mass percentage;

[0025] Preferably, the amount of the leakage current inhibitor added is 0.01-5.00% of the total amount of the electrolyte, preferably 0.01-1.00%, by mass percentage.

[0026] Preferably, the electrolyte further comprises other organic carboxylic acids or ammonium salts thereof in addition to the cycloolefin carboxylic acid ammonium salt compound;

[0027] Other organic carboxylic acids or their ammonium salts are selected from one or more of sebacic acid, azelaic acid, benzoic acid, adipic acid, sebacic acid, dodecanedioic acid, 1,6-dodecanedioic acid, 1,7-sebacic acid and ammonium salts of the above acids, and their added amount preferably accounts for 1.00-20.00% of the total amount of the electrolyte.

[0028] The present invention also provides a medium- and high-voltage aluminum electrolytic capacitor using the above-mentioned electrolyte for the aluminum electrolytic capacitor.

[0029] Beneficial effects:

[0030] The beneficial effects of the technical solution of the present invention are as follows:

[0031] As electrolyte solutes, cycloolefin carboxylic acid ammonium salt compounds have good solubility, low-temperature antifreeze properties, and high electrical conductivity. When they are used in electrolytes together with inorganic boron compounds, they also have good thermal stability and long life characteristics at high temperatures (especially 125°C). DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention is clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In this embodiment, the cycloolefin carboxylic acid ammonium salt compound is used as the solute, and an inorganic boron compound is added thereto as a buffer, and the resulting electrolyte is applied to capacitors, which has higher thermal stability and longer life. The specific embodiments are as follows:

[0034] An electrolyte for an aluminum electrolytic capacitor comprises a solute, a solvent and an additive, wherein the solute comprises a cycloolefin carboxylic acid ammonium salt compound, and the additive comprises an inorganic boron compound, wherein the structural formula of the cycloolefin carboxylic acid ammonium salt compound is as shown in formula (1) or formula (2):

[0035]

[0036] A is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, a carboxyl group and an ammonium carboxylate group; B is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms; x and y are integers, and the value of x+y is 0-30.

[0037] As a preferred embodiment, the cycloolefin carboxylate ammonium salt compound is selected from 4-hexyl-6-carboxylic acid ammonium-cyclohex-2-ene-1-octanoic acid ammonium, 4-hexyl-5,6-dicarboxylic acid ammonium-6 methyl-cyclohex-2-ene-1-octanoic acid ammonium, 4-hexyl-6-carboxylic acid ammonium-6 methyl-cyclohex-2-ene-1-octanoic acid ammonium, 6-propyl-1,3,5 tricarboxylic acid ammonium-cyclohex-2-ene and 4-hexyl-5-ethyl-6-carboxylic acid ammonium-cyclohex-2-ene-1-octanoic acid ammonium, 4-hexyl-5-butyl-6-carboxylic acid ammonium-cyclohex-2-ene-1-octanoic acid ammonium.

[0038] As a preferred embodiment, the inorganic boron compound is selected from one or more of boric acid, ammonium diborate, ammonium pentaborate and boric acid polyol ester.

[0039] As a preferred embodiment, the amount of the cycloolefin carboxylic acid ammonium salt compound added is 0.10-30.00% of the total amount of the electrolyte by mass percentage; preferably 0.50-15.00%;

[0040] As a preferred embodiment, the inorganic boron compound is added in an amount of 1.00-10.00% of the total amount of the electrolyte, preferably 2.00-5.00%.

[0041] As a preferred embodiment, the solvent accounts for 60-95% of the total amount of the electrolyte by mass percentage, preferably 70-90% of the solvent is selected from one or more of alcohols, alcohol ethers, amides, sulfones, sulfoxides and esters; preferably, the solvent is ethylene glycol or r-butyrolactone.

[0042] As a preferred embodiment, the additives also include one or more of a waterproofing agent, a hydrogen scavenger, a flash enhancer, an anti-corrosion additive and a leakage current inhibitor.

[0043] As a preferred embodiment, the waterproofing mixture is selected from one or more of hypophosphorous acid, phosphorous acid, phosphoric acid and monoalkyl phosphate, or one or more of ammonia or amine salts of hypophosphorous acid, phosphorous acid, phosphoric acid and monoalkyl phosphate;

[0044] As a preferred embodiment, the hydrogen remover is selected from one or more of p-nitrophenol, p-nitrobenzyl alcohol, o-nitroanisole and m-nitroacetophenone;

[0045] As a preferred embodiment, the flash enhancer is selected from one or more of silica melt, polyvinyl alcohols, polyethylene glycols, polyvinyl alcohol borates, polyvinyl alcohol phosphates, polyvinyl pyrrolidone and mannitol;

[0046] The anti-corrosion additive is selected from one or more of nitrilotriacetic acid, EDTA, silver benzoate and 8-hydroxyquinoline;

[0047] The leakage current inhibitor is selected from one or more of phosphotungstic acid, molybdotungstic acid, 3,5-dihydroxybenzoic acid and strontium nitrate.

[0048] As a preferred embodiment, the amount of the waterproof mixture added is 0.05-5.00% of the total amount of the electrolyte, preferably 0.10-3.00% by mass;

[0049] As a preferred embodiment, the amount of the hydrogen remover added is 0.10-15.00% of the total amount of the electrolyte, preferably 0.20-4.00% by mass;

[0050] As a preferred embodiment, the amount of the flash enhancer added is 0.20-15.00% of the total amount of the electrolyte, preferably 0.50-10.00% by mass;

[0051] As a preferred embodiment, the amount of the anti-corrosion additive added is 0.01-5.00% of the total amount of the electrolyte, preferably 0.01-1.00% by mass;

[0052] As a preferred embodiment, the amount of the leakage current inhibitor added is 0.01-5.00% of the total amount of the electrolyte, preferably 0.01-1.00%, by mass percentage.

[0053] As a preferred embodiment, the electrolyte further comprises other organic carboxylic acids or ammonium salts thereof in addition to the cycloolefin carboxylic acid ammonium salt compound;

[0054] Other organic carboxylic acids or their ammonium salts are selected from one or more of sebacic acid, azelaic acid, benzoic acid, adipic acid, sebacic acid, dodecanedioic acid, 1,6-dodecanedioic acid, 1,7-sebacic acid and ammonium salts of the above acids, and their added amount preferably accounts for 1.00-20.00% of the total amount of the electrolyte.

[0055] This embodiment also provides an aluminum electrolytic capacitor using the above-mentioned electrolyte for an aluminum electrolytic capacitor.

[0056] The beneficial effects of the electrolyte of the present invention are further described below through several groups of examples and comparative examples.

[0057] Embodiment 1:

[0058] Thermal stability test of olefin carboxylic acid ammonium salt compounds at 105°C

[0059] Preparation method: The compound involved in formula (1) or formula (2) in this embodiment is dissolved in ethylene glycol to prepare a 5% concentration ethylene glycol solution, which is sealed in a stainless steel bottle and kept at 105°C for a period of time. The changes in various parameters are shown in the following table:

[0060] Table 1 Conductivity changes after constant temperature at 105℃

[0061]

[0062]

[0063] From the above data, it can be concluded that the conductivity change value of the compound involved in formula (1) or formula (2) in this embodiment after being kept at 105°C for a period of time is about -53%, while that of ammonium sebacate is about -74%, and that of 2-hexylammonium adipate is about -46%. The results show that the stability of the compound involved in formula (1) or formula (2) is better than that of ammonium sebacate and inferior to that of 2-hexylammonium adipate.

[0064] Embodiment 2:

[0065] Thermal stability test of olefin carboxylic acid ammonium salt compound and combination of olefin carboxylic acid ammonium salt compound and inorganic boron compound at 125°C

[0066] 1. Preparation method of stock solution: dissolve the compound involved in formula (1) or formula (2) in this embodiment in ethylene glycol to prepare a 5% concentration ethylene glycol solution, and seal it in a stainless steel bottle;

[0067] 2. Preparation method of stock solution + 3% ammonium pentaborate: dissolve the compound involved in formula (1) or formula (2) in this embodiment and ammonium pentaborate in ethylene glycol to prepare an ethylene glycol solution of 5% concentration of cycloolefin carboxylic acid ammonium salt + 3% ammonium pentaborate, and seal it in a stainless steel bottle;

[0068] 3. The changes of various parameters of the electrolyte prepared by methods 1 and 2 above at a constant temperature of 125°C for a period of time. The details are as follows:

[0069] Table 21 Conductivity change after constant temperature at 25℃ (change rate is a comparison between 2000h and 0h)

[0070]

[0071]

[0072] From the above data and phenomena, it can be concluded that the conductivity change rate of the compound solution involved in formula (1) or formula (2) in this embodiment is about -76% after being kept at a constant temperature of 125°C for a period of time, and after adding a certain amount of ammonium pentaborate, the conductivity change rate is about -17%, which is a very obvious improvement.

[0073] Embodiment three:

[0074] Prepare electrolyte and conduct capacitor experimental tests

[0075] According to the proportions in Table 3 and Table 4, a high-voltage electrolyte was prepared and the basic indicators were tested as shown in Table 5. Finally, a capacitor was made and tested for capacitance, leakage current, loss, ESR and other properties as shown in Table 6.

[0076] Table 3 Proportions of components in the electrolytes of various embodiments and comparative examples

[0077]

[0078] Table 4 Addition amount of each component in each embodiment and comparative example electrolyte

[0079]

[0080]

[0081] Table 5 Basic parameters of electrolyte

[0082] Electrolyte Conductivity / mS / cm pH Moisture / % Normal temperature flash fire / V 85℃ flash voltage / V Example 1 1.241 6.15 2.55 559 517 Example 2 1.236 6.17 2.68 563 520 Example 3 1.227 6.18 2.69 568 522 Example 4 1.229 6.20 3.25 549 509 Example 5 1.237 6.22 2.99 564 514 Example 6 1.231 6.19 2.65 562 510 Example 7 1.227 6.21 2.75 560 517 Comparative Example 1 1.257 6.87 1.56 548 499 Comparative Example 2 1.232 6.89 1.65 552 509

[0083] 500V electrolyte and device performance-life test results

[0084] The electrolytes in Examples 1 to 7 and Comparative Examples 1 and 2 were made into capacitors, with the specifications of 500v47035x50 and positive foil 700VF 0.47μF / cm 2 , negative electrode foil 2VF, electrolytic paper is domestic WD270-40+W180-30, and the cover is 33.8*3.0PP film.

[0085] The 500V electrolyte and device performance-life test were conducted, and the test results are shown in Table 6.

[0086] Table 6 125℃ ripple load life test results

[0087]

[0088]

[0089] As shown in Table 6, after the electrolytes in Examples 1 to 7 were made into capacitors, the basic parameters of capacitance, leakage current, loss and ESR changed little after a long-term ripple load life experiment. Compared with Comparative Examples 1 and 2 without adding inorganic borate electrolyte, they have higher stability and passed the 125°C ripple life test for 1000h. After the life experiment, the capacitors were dissected and no abnormal conditions such as corrosion, breakdown and hydration were found. However, the parameters of the comparative examples without adding inorganic boron compounds changed greatly and exceeded the qualified range.

[0090] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electrolyte for medium and high voltage aluminum electrolytic capacitors, characterized in that: The invention comprises a solute, a solvent and an additive, wherein the solute comprises a cycloolefin carboxylic acid ammonium salt compound, and the additive comprises an inorganic boron compound, wherein the structural formula of the cycloolefin carboxylic acid ammonium salt compound is as shown in formula (1) or formula (2): A is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms, a carboxyl group, or an ammonium carboxylate group; B is a hydrogen atom or a hydrocarbon group containing 1 to 10 carbon atoms; x and y are integers, and the value of x+y is 0-30.

2. The electrolyte for medium and high voltage aluminum electrolytic capacitors according to claim 1, characterized in that: The cycloolefin carboxylate ammonium salt compound is selected from 4-hexyl-6-carboxylate ammonium-cyclohex-2-ene-1-octanoic acid ammonium, 4-hexyl-5,6-dicarboxylate ammonium-6 methyl-cyclohex-2-ene-1-octanoic acid ammonium, 4-hexyl-6-carboxylate ammonium-6 methyl-cyclohex-2-ene-1-octanoic acid ammonium, 6-propyl-1,3,5 tricarboxylate ammonium-cyclohex-2-ene and 4-hexyl-5-ethyl-6-carboxylate ammonium-cyclohex-2-ene-1-octanoic acid ammonium, 4-hexyl-5-butyl-6-carboxylate ammonium-cyclohex-2-ene-1-octanoic acid ammonium.

3. The electrolyte for medium and high voltage aluminum electrolytic capacitors according to claim 1, characterized in that: The inorganic boron compound is selected from one or more of boric acid, ammonium diborate, ammonium pentaborate and boric acid esters.

4. The electrolyte for medium and high voltage aluminum electrolytic capacitors according to claim 1, characterized in that: In terms of mass percentage, the amount of the cycloolefin carboxylic acid ammonium salt compound added is 0.10-30.0% of the total amount of the electrolyte; preferably 0.50-15.00%; Preferably, the inorganic boron compound is added in an amount of 1.00-10.00% of the total amount of the electrolyte, preferably 2.00-5.00%.

5. The electrolyte for medium and high voltage aluminum electrolytic capacitors according to claim 1, characterized in that: In terms of mass percentage, the solvent accounts for 60.00-95.00% of the total amount of the electrolyte, and the solvent is selected from one or more of alcohols, alcohol ethers, amides, sulfones, sulfoxides and esters; preferably, the solvent is ethylene glycol or γ-butyrolactone.

6. The electrolyte for medium and high voltage aluminum electrolytic capacitors according to claim 1, characterized in that: The additives also include one or more of a waterproofing agent, a hydrogen scavenger, a flash enhancer, an anti-corrosion additive, and a leakage current inhibitor.

7. The electrolyte for medium and high voltage aluminum electrolytic capacitors according to claim 6, characterized in that: The waterproofing mixture is selected from one or more of hypophosphorous acid, phosphorous acid, phosphoric acid and monoalkyl phosphate, or selected from one or more of ammonium or amine salts of hypophosphorous acid, phosphorous acid, phosphoric acid and monoalkyl phosphate; Preferably, the hydrogen remover is selected from one or more of p-nitrophenol, p-nitrobenzyl alcohol, o-nitroanisole and m-nitroacetophenone; Preferably, the flash enhancer is selected from one or more of silica melt, polyvinyl alcohols, polyethylene glycols, polyvinyl alcohol borates, polyvinyl alcohol phosphates, polyvinyl pyrrolidone and mannitol; The anti-corrosion additive is selected from one or more of nitrilotriacetic acid, EDTA, silver benzoate and 8-hydroxyquinoline; The leakage current inhibitor is selected from one or more of phosphotungstic acid, molybdotungstic acid, 3,5-dihydroxybenzoic acid and strontium nitrate.

8. The electrolyte for medium and high voltage aluminum electrolytic capacitors according to claim 7, characterized in that: In terms of mass percentage, the amount of the waterproof mixture added is 0.05-5.00% of the total amount of the electrolyte, preferably 0.10-3.00%; Preferably, the amount of the hydrogen remover added is 0.10-15.00% of the total amount of the electrolyte, preferably 0.20-4.00% by mass percentage; Preferably, the amount of the flash enhancer added is 0.20-15.00% of the total amount of the electrolyte, preferably 0.50-10.00% by mass; Preferably, the amount of the anti-corrosion additive added is 0.01-5.00% of the total amount of the electrolyte, preferably 0.01-1.00% by mass percentage; Preferably, the amount of the leakage current inhibitor added is 0.01-5.00% of the total amount of the electrolyte, preferably 0.01-1.00%, by mass percentage.

9. The electrolyte for medium and high voltage aluminum electrolytic capacitors according to claim 1, characterized in that: The electrolyte further includes other organic carboxylic acids or ammonium salts thereof in addition to the cycloolefin carboxylic acid ammonium salt compound; Other organic carboxylic acids or their ammonium salts are selected from one or more of sebacic acid, azelaic acid, benzoic acid, adipic acid, sebacic acid, dodecanedioic acid, 1,6-dodecanedioic acid, 1,7-sebacic acid and ammonium salts of the above acids, and their added amount preferably accounts for 1.00-20.00% of the total amount of the electrolyte.

10. A medium- and high-voltage aluminum electrolytic capacitor, characterized in that: Use the electrolyte for aluminum electrolytic capacitors as described in any one of claims 1 to 9.

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