A vibration-resistant aluminum electrolytic capacitor and its preparation method

Abstract

An anti-vibration aluminum electrolytic capacitor has an outer layer of core package wrapped with anti-vibration tape. The anti-vibration tape includes a pressure-sensitive adhesive layer, a water-absorbing and swelling functional layer, and a substrate layer. The pressure-sensitive adhesive layer is disposed on the water-absorbing and swelling functional layer, which is also disposed on the substrate layer. The pressure-sensitive adhesive layer is in contact with the outermost layer of the core package. After the water-absorbing and swelling functional layer absorbs water and expands, it tightly adheres the substrate layer to the inner wall of the aluminum shell. The water-absorbing and swelling functional layer includes a water-absorbing and swelling resin, an adhesive, and additives. The water-absorbing and swelling resin includes one or more combinations of polyacrylates, polyacrylamides, and cellulose graft copolymers. After the core package of this invention is impregnated with electrolyte, the water-absorbing and swelling functional layer located in the middle layer of the anti-vibration tape absorbs water from the aqueous electrolyte and slowly expands, increasing its volume to 2 to 5 times its original thickness. This allows the substrate layer to tightly adhere to the inner wall of the aluminum shell, achieving gapless self-locking. The pressure-sensitive adhesive layer maintains good adhesion after impregnation, ensuring that the tape as a whole does not shift.

Description

Technical Field

[0001] This invention relates to an aluminum electrolytic capacitor, and more particularly to a vibration-resistant liquid aluminum electrolytic capacitor and its preparation method. Background Technology

[0002] Aluminum electrolytic capacitors are typically made by winding anode foil, cathode foil, and electrolytic paper into a core package, which is then impregnated with electrolyte and encapsulated in an aluminum shell. In applications with high vibration, such as automotive electronics and industrial frequency converters, if there is a tiny gap between the core package and the aluminum shell, long-term vibration can easily cause core package displacement and friction, leading to failure problems such as lead wire breakage, internal short circuits, or electrolyte leakage.

[0003] Current mainstream vibration-damping measures mainly fall into two categories: one relies on the interference fit between the rubber plug and the aluminum shell for fixation; the other involves applying adhesive between the core package and the aluminum shell for curing. However, rubber plugs are prone to aging and loss of elasticity after long-term use, resulting in a decrease in vibration-damping performance; the adhesive application process is complex, the adhesive has difficulty penetrating deep into the gaps of the core package, and the consistency of the adhesive application is poor, affecting product reliability. Therefore, there is an urgent need for a vibration-damping solution that can actively fill gaps and has strong process adaptability. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an anti-vibration aluminum electrolytic capacitor and its preparation method.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by the present invention is as follows: a vibration-resistant aluminum electrolytic capacitor, comprising a core, a shell, and a sealing element, wherein the core is sealed inside the shell by the sealing element; the outer layer of the core is wrapped with vibration-resistant tape; the vibration-resistant tape comprises a pressure-sensitive adhesive layer, a water-absorbing and swelling functional layer, and a substrate layer, wherein the pressure-sensitive adhesive layer is disposed on the water-absorbing and swelling functional layer, and the water-absorbing and swelling functional layer is disposed on the substrate layer; the pressure-sensitive adhesive layer is in contact with the outermost layer of the core, and the water-absorbing and swelling functional layer, after absorbing water and swelling, causes the substrate layer to adhere tightly to the inner wall of the aluminum shell; the water-absorbing and swelling functional layer comprises a water-absorbing and swelling resin, an adhesive, and an additive, wherein the water-absorbing and swelling resin comprises one or more combinations of polyacrylates, polyacrylamides, and cellulose graft copolymers.

[0006] Preferably, in the above-mentioned vibration-resistant aluminum electrolytic capacitor, the adhesive comprises one or more mixtures of waterborne polyurethane, polyvinyl alcohol (PVA), styrene-butadiene rubber latex (SBR latex), and polyacrylate latex.

[0007] Preferably, in the above-mentioned vibration-resistant aluminum electrolytic capacitor, the additives include: a dispersant, an antifoaming agent, a plasticizer, and a first crosslinking agent; the dispersant includes sodium polyacrylate and / or sodium hexametaphosphate; the antifoaming agent includes a polyether-based antifoaming agent; and the plasticizer includes glycerol and / or propylene glycol.

[0008] Preferably, in the above-mentioned anti-vibration aluminum electrolytic capacitor, the first crosslinking agent includes one or more of N,N'-methylenebisacrylamide (NMBA / MBA), polyethylene glycol diacrylate (PEGDA), glutaraldehyde, and epoxy crosslinking agents (such as ethylene glycol diglycidyl ether).

[0009] Preferably, in the above-mentioned vibration-resistant aluminum electrolytic capacitor, the pressure-sensitive adhesive layer comprises 50–80 parts by weight of acrylate pressure-sensitive adhesive, 5–20 parts by weight of tackifying resin, and 0.5–3 parts by weight of a second crosslinking agent.

[0010] Preferably, in the above-mentioned anti-vibration aluminum electrolytic capacitor, the tackifying resin includes rosin ester and / or terpene phenol resin.

[0011] Preferably, in the above-mentioned vibration-resistant aluminum electrolytic capacitor, the second crosslinking agent includes one or more of the following: isocyanate crosslinking agents, epoxy crosslinking agents, metal chelate crosslinking agents, aziridine crosslinking agents, and multifunctional acrylate crosslinking agents.

[0012] Preferably, in the aforementioned vibration-resistant aluminum electrolytic capacitor, the substrate layer comprises one of polyester, polyimide, or polypropylene film.

[0013] A method for preparing an anti-vibration aluminum electrolytic capacitor includes the following steps:

[0014] 1) Preparation of anti-vibration tape;

[0015] 1.1) Preparation of pressure-sensitive adhesive coating solution: Add 50-80 parts by weight of acrylic pressure-sensitive adhesive, 5-20 parts by weight of tackifying resin and 0.5-3 parts by weight of crosslinking agent to 100-300 parts by weight of the first solvent and disperse evenly;

[0016] 1.2) Preparation of water-absorbing and swelling coating liquid: 30-60 parts by weight of water-absorbing and swelling resin, 10-30 parts by weight of binder, 1-5 parts by weight of crosslinking agent and 0.5-3 parts by weight of additives are added to 100-400 parts by weight of second solvent and dispersed at high speed until uniform;

[0017] 1.3) A step-by-step coating method is adopted: first, a water-absorbing and swelling functional layer is coated on one side of the substrate layer and dried and cured at a temperature of 80-120 ℃; then, a pressure-sensitive adhesive layer is coated on the outer layer of the water-absorbing and swelling functional layer and dried and cured at a temperature of 80-120 ℃.

[0018] 1.4) The tape is wound up and slit to obtain the anti-vibration tape;

[0019] 2) The anode foil, electrolytic paper and cathode foil are wound together to form a core package, and at least one layer of anti-vibration tape is wrapped around the outermost layer of the core package;

[0020] 3) Immerse the core from step 2) in an electrolyte, wherein the electrolyte is an aqueous electrolyte;

[0021] 4) Pack the core package from step 3) into the outer casing and then seal it with a sealant; let it stand for more than 12 hours to form an anti-vibration aluminum electrolytic capacitor.

[0022] Compared with the prior art, the advantages of the present invention are as follows: After the core package of the present invention is impregnated with electrolyte, the water-absorbing and swelling functional layer located in the middle layer of the anti-vibration tape absorbs the water in the aqueous electrolyte and slowly expands, increasing in volume to 2 to 5 times the original thickness. This allows the substrate layer to tightly adhere to the inner wall of the aluminum shell, achieving gapless self-locking. The pressure-sensitive adhesive layer maintains good adhesion after impregnation, ensuring that the tape as a whole does not shift. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the vibration-resistant aluminum electrolytic capacitor in Example 1.

[0024] Figure 2 This is a cross-sectional view of the anti-vibration tape in Example 1.

[0025] Legend

[0026] 1. Core package; 2. Outer shell; 3. Sealing element; 4. Anti-vibration tape; 41. Pressure-sensitive adhesive layer; 42. Water absorption and expansion functional layer; 43. Substrate layer. Detailed Implementation

[0027] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0028] It should be noted that when a component is described as being "fixed to, attached to, connected to or connected to" another component, it can be directly fixed to, attached to, connected to or connected to the other component, or it can be indirectly fixed to, attached to, connected to or connected to the other component through other intermediate connectors.

[0029] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0030] An anti-vibration aluminum electrolytic capacitor includes a core, a shell, and a seal. The core is sealed within the shell by the seal; in this embodiment, the seal is a rubber stopper. The outer layer of the core is wrapped with anti-vibration tape. The anti-vibration tape includes a pressure-sensitive adhesive layer, a water-absorbing and swelling functional layer, and a substrate layer. The pressure-sensitive adhesive layer is disposed on the water-absorbing and swelling functional layer, which is also disposed on the substrate layer. The pressure-sensitive adhesive layer is in contact with the outermost layer of the core. After absorbing water and swelling, the water-absorbing and swelling functional layer tightly adheres the substrate layer to the inner wall of the aluminum shell. The water-absorbing and swelling functional layer includes a water-absorbing and swelling resin, an adhesive, and additives. The water-absorbing and swelling resin includes one or more combinations of polyacrylates, polyacrylamides, and cellulose graft copolymers. In this embodiment, the substrate layer includes one of polyester (PET), polyimide (PI), or polypropylene (PP) film.

[0031] In this embodiment, the binder includes one or more mixtures of waterborne polyurethane, polyvinyl alcohol (PVA), styrene-butadiene rubber latex (SBR latex), and polyacrylate latex. Additives include: leveling agents such as BYK series and TegoGlide; dispersants such as sodium polyacrylate and sodium hexametaphosphate; defoamers such as polyether defoamers; plasticizers such as glycerin and propylene glycol; and a first crosslinking agent. The first crosslinking agent includes one or more mixtures of N,N'-methylenebisacrylamide (NMBA / MBA), polyethylene glycol diacrylate (PEGDA), glutaraldehyde, and epoxy crosslinking agents; epoxy crosslinking agents include ethylene glycol diglycidyl ether.

[0032] In this embodiment, the pressure-sensitive adhesive layer comprises 50–80 parts by weight of acrylate pressure-sensitive adhesive, 5–20 parts by weight of tackifying resin, and 0.5–3 parts by weight of a second crosslinking agent. The tackifying resin comprises one or both of rosin ester and terpene phenol resin.

[0033] This embodiment also provides a method for preparing an anti-vibration aluminum electrolytic capacitor, including the following steps:

[0034] 1) Preparation of anti-vibration tape;

[0035] 1.1) Preparation of pressure-sensitive adhesive coating solution: Add 50-80 parts by weight of acrylate pressure-sensitive adhesive, 5-20 parts by weight of tackifying resin and 0.5-3 parts by weight of crosslinking agent to 100-300 parts by weight of first solvent and disperse evenly; the first solvent can be ethyl acetate, toluene or a mixture thereof.

[0036] 1.2) Preparation of water-absorbing and swelling coating liquid: 30-60 parts by weight of water-absorbing and swelling resin, 10-30 parts by weight of binder, 1-5 parts by weight of crosslinking agent and 0.5-3 parts by weight of additives are added to 100-400 parts by weight of second solvent and dispersed at high speed and uniformly; the second solvent can be one or more of deionized water, ethanol, ethylene glycol and glycerol.

[0037] 1.3) A step-by-step coating method is adopted: first, a water-absorbing and swelling functional layer is coated on one side of the substrate layer and dried and cured at a temperature of 80-120 ℃; then, a pressure-sensitive adhesive layer is coated on the outer layer of the water-absorbing and swelling functional layer and dried and cured at a temperature of 80-120 ℃.

[0038] 1.4) The tape is wound up and slit to obtain the anti-vibration tape;

[0039] 2) The anode foil, electrolytic paper and cathode foil are wound together to form a core package, and at least one layer of anti-vibration tape is wrapped around the outermost layer of the core package;

[0040] 3) Immerse the core from step 2) in an electrolyte, wherein the electrolyte is an aqueous electrolyte;

[0041] 4) Pack the core package from step 3) into the outer casing and then seal it with a sealant; let it stand for more than 12 hours to form an anti-vibration aluminum electrolytic capacitor.

[0042] Aqueous electrolytes in aluminum electrolytic capacitors typically contain more than 3% water by weight. In this invention, after the core package is impregnated with the aqueous electrolyte, the water-absorbing and swelling functional layer located in the middle layer of the vibration-damping tape absorbs the water from the aqueous electrolyte and slowly expands, increasing in volume to 2-3 times its original thickness. This allows the substrate layer to tightly adhere to the inner wall of the aluminum shell, achieving gapless self-locking. The pressure-sensitive adhesive layer maintains good adhesion after impregnation, ensuring that the tape as a whole does not shift.

[0043] Example 1

[0044] Preparation of pressure-sensitive adhesive coating solution: Take 65 parts by weight of acrylic pressure-sensitive adhesive, 12 parts by weight of rosin ester tackifying resin, 1.5 parts by weight of isocyanate crosslinking agent, add 100 parts by weight of ethyl acetate solvent, and disperse evenly.

[0045] Preparation of water-absorbing and swelling coating solution: Take 40 parts by weight of sodium polyacrylate water-absorbing and swelling resin, 20 parts by weight of acrylic ester binder, 2 parts by weight of aziridine crosslinking agent, and 1 part by weight of dispersant, add 100 parts by weight of deionized water, and disperse evenly at high speed.

[0046] A step-by-step coating method is adopted: the water-absorbing and swelling coating liquid is coated on one side of a 12 μm thick PET film, the dry film thickness is controlled at about 25 μm, and it is dried and cured at 100 ℃. Then, the pressure-sensitive adhesive coating liquid is coated on the other side of the water-absorbing and swelling layer by gravure coating, the dry film thickness is controlled at about 10 μm, and it is dried at 100 ℃; then it is wound up and slit.

[0047] The prepared anti-vibration tape is wrapped around the outermost layer of the aluminum electrolytic capacitor core, and the pressure-sensitive adhesive layer is tightly bonded to the surface of the core. After the core is impregnated with electrolyte (1.5% water content), the water-absorbing and swelling functional layer expands to 2.5 times its original thickness within 24 hours, so that the tape base layer is tightly bonded to the inner wall of the aluminum shell.

[0048] Example 2

[0049] Pressure-sensitive adhesive coating solution: Take 70 parts by weight of acrylate pressure-sensitive adhesive, 10 parts by weight of terpene phenol resin, 2 parts by weight of epoxy crosslinking agent, add 120 parts by weight of toluene solvent, and disperse evenly.

[0050] Water-absorbing and swelling coating solution: Take 50 parts of hydroxypropyl cellulose grafted acrylamide resin, 15 parts of polyurethane adhesive, 3 parts of epoxy crosslinking agent, and 0.5 parts of leveling agent, add them to a second solvent composed of 120 parts of ethanol and deionized water, and disperse evenly.

[0051] A dual-layer simultaneous coating method was adopted: a pressure-sensitive adhesive layer and a water-absorbing and swelling functional layer were simultaneously coated on both sides of a 16μm thick polyimide film. The dry film thickness of the pressure-sensitive adhesive layer was controlled at 12μm, and the dry film thickness of the water-absorbing and swelling functional layer was controlled at 30μm. The film was then cured in stages at 110℃.

[0052] A step-by-step coating method is adopted: the water-absorbing and swelling coating liquid is coated on one side of a 16 μm thick PET film, the dry film thickness is controlled at 30 μm, and it is dried and cured at 110 ℃. Then, the pressure-sensitive adhesive coating liquid is coated on the other side of the water-absorbing and swelling layer by gravure coating, the dry film thickness is controlled at 12 μm, and it is dried at 110 ℃.

[0053] The tape is attached to the side of the core package, and the rest is the same as in Example 1. After impregnation, the water-absorbing and swelling functional layer expands by approximately 3.9 times, allowing the tape substrate layer to adhere tightly to the inner wall of the aluminum shell.

[0054] Comparative Example 1

[0055] In Comparative Example 1, the outermost layer of the core package was wrapped with conventional transparent tape; otherwise, it was the same as in Example 1.

[0056] Twenty products from Examples 1, 2, and Comparative Example 1 were taken respectively and subjected to vibration tests. The vibration test parameters were frequency 10–500 Hz, acceleration 5 g, and duration 8 h. The results are shown in the table below. After the vibration test, the capacitor capacitance of the products from Examples 1 and 2 changed by ≤3%, the loss tangent changed by ≤2%, and there were no lead wire breaks, short circuits, or leakage, and no tape peeling.

[0057] Serial Number Average rate of change of capacitance after vibration test Average rate of change of loss tangent after vibration test There are no signs of broken leads, short circuits, or leakage. Example 1 0.07% 0.04% none Example 2 0.01% 0.03% none Comparative Example 1 4.54% 1.90% Lead wire breakage, leakage .

[0058] As can be seen from the table above, the vibration resistance performance of Examples 1 and 2 is significantly better than that of the control group that did not use vibration-resistant tape.

Claims

1. A vibration-resistant aluminum electrolytic capacitor, characterized in that: The device includes a core package, an outer shell, and a seal. The core package is sealed within the outer shell by the seal. An anti-vibration tape is wound around the outer layer of the core package. The anti-vibration tape includes a pressure-sensitive adhesive layer, a water-absorbing and swelling functional layer, and a substrate layer. The pressure-sensitive adhesive layer is disposed on the water-absorbing and swelling functional layer, which is disposed on the substrate layer. The pressure-sensitive adhesive layer is in contact with the outermost layer of the core package. After absorbing water and swelling, the water-absorbing and swelling functional layer causes the substrate layer to adhere tightly to the inner wall of the aluminum shell. The water-absorbing and swelling functional layer includes a water-absorbing and swelling resin, an adhesive, and additives. The water-absorbing and swelling resin includes one or more combinations of polyacrylates, polyacrylamides, and cellulose graft copolymers.

2. The vibration-resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The adhesive includes one or more mixtures of waterborne polyurethane, polyvinyl alcohol, styrene-butadiene rubber latex, and polyacrylate latex.

3. The vibration-resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The additives include: a dispersant, an antifoaming agent, a plasticizer, and a first crosslinking agent; the dispersant includes sodium polyacrylate and / or sodium hexametaphosphate; the antifoaming agent includes a polyether-based antifoaming agent; and the plasticizer includes glycerol and / or propylene glycol.

4. The vibration-resistant aluminum electrolytic capacitor according to claim 3, characterized in that: The first crosslinking agent includes one or more mixtures of N,N'-methylenebisacrylamide, polyethylene glycol diacrylate, glutaraldehyde, and epoxy crosslinking agents.

5. The vibration-resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The pressure-sensitive adhesive layer comprises 50–80 parts by weight of acrylate pressure-sensitive adhesive, 5–20 parts by weight of tackifying resin, and 0.5–3 parts by weight of a second crosslinking agent.

6. The vibration-resistant aluminum electrolytic capacitor according to claim 5, characterized in that: The second crosslinking agent includes one or more of the following: isocyanate crosslinking agents, epoxy crosslinking agents, metal chelate crosslinking agents, aziridine crosslinking agents, and multifunctional acrylate crosslinking agents.

7. The anti-vibration aluminum electrolytic capacitor according to claim 5, wherein the tackifying resin comprises rosin ester and / or terpene phenol resin.

8. The vibration-resistant aluminum electrolytic capacitor according to claim 1, characterized in that: The substrate layer includes one of polyester, polyimide, or polypropylene film.

9. The method for preparing the vibration-resistant aluminum electrolytic capacitor according to any one of claims 1-8, characterized in that; Includes the following steps: 1) Preparation of anti-vibration tape; 1.1) Preparation of pressure-sensitive adhesive coating solution: Add 50-80 parts by weight of acrylic pressure-sensitive adhesive, 5-20 parts by weight of tackifying resin and 0.5-3 parts by weight of crosslinking agent to 100-300 parts by weight of the first solvent and disperse evenly; 1.2) Preparation of water-absorbing and swelling coating liquid: 30-60 parts by weight of water-absorbing and swelling resin, 10-30 parts by weight of binder, 1-5 parts by weight of crosslinking agent and 0.5-3 parts by weight of additives are added to 100-400 parts by weight of second solvent and dispersed at high speed until uniform; 1.3) A step-by-step coating method is adopted: first, a water-absorbing and swelling functional layer is coated on one side of the substrate layer and dried and cured at a temperature of 80~120 ℃; then, a pressure-sensitive adhesive layer is coated on the outer layer of the water-absorbing and swelling functional layer and dried and cured at a temperature of 80~120 ℃. 1.4) The tape is wound up and slit to obtain the anti-vibration tape; 2) The anode foil, electrolytic paper and cathode foil are wound together to form a core package, and at least one layer of anti-vibration tape is wrapped around the outermost layer of the core package; 3) Immerse the core from step 2) in an electrolyte, wherein the electrolyte is an aqueous electrolyte; 4) Pack the core package from step 3) into the outer casing and then seal it with a sealant; let it stand for more than 12 hours to form an anti-vibration aluminum electrolytic capacitor.

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