Efficient oil-resistant sealing cover plate of aluminum electrolytic capacitor

Abstract

The utility model relates to a high-efficiency oil-resistant sealing cover plate of an aluminum electrolytic capacitor. The sealing cover plate is characterized in that the sealing cover plate comprises a substrate layer, an oil-resistant layer and a sealing layer; an oil-resistant layer is arranged on the upper end surface of the substrate layer; a sealing layer is arranged on the bottom surface of the substrate layer; adjacent contact end surfaces of the substrate layer, the oil-resistant layer and the sealing layer are mutually embedded to form an integrally formed plate structure; two through holes are symmetrically formed in the end face of the sealing cover plate close to the middle; the through hole penetrates through the substrate layer, the oil-resistant layer and the sealing layer; and metal nails for leading out a positive electrode and a negative electrode are respectively inserted into the two through holes. The sealing cover plate has the advantages of being good in sealing performance and high in oil separation and corrosion resistance, the aluminum electrolytic capacitor sealed through the sealing cover plate plays a role in sealing vaporization of electrolyte internally and plays a role in blocking oil permeation externally, and the problems that an existing aluminum electrolytic capacitor is poor in stability and poor in oil resistance and oil resistance are solved.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of aluminum electrolytic capacitor, especially a high -efficient oil -resistant sealing cover plate of aluminum electrolytic capacitor. BACKGROUND

[0002] At present, the electronic industry such as domestic and foreign high-end servers, power products have new development direction for the heat dissipation mode of electronic components, gradually transform from traditional air cooling to new spray or immersion liquid cooling. Commonly used cooling liquid includes fluorocarbon cooling liquid, hydrocarbon mineral oil, synthetic oil, etc., from the cost and environmental protection angle, the industry is more inclined to use the mineral oil with performance to meet the demand as the medium of heat dissipation. In this case, aluminum electrolytic capacitor is required to adapt to stable operation in oil-containing environment, which puts forward new requirements for the sealing performance of aluminum electrolytic capacitor, and the sealing material not only blocks the internal electrolyte volatilization, but also blocks the external oil and impurities into the capacitor.

[0003] For the traditional aluminum electrolytic capacitor with the diameter between 20mm-45mm, the sealing material bakelite cover structure is phenolic resin laminated plate with rubber layer, the rubber layer is on the outer surface, and the material is ethylene propylene diene rubber. The sealing property of ethylene propylene diene rubber to mineral oil is poor. At present, the general practice in the industry is to smear organic glue on the outer surface of the bakelite cover rubber, such as epoxy resin, organic silicon, polyurethane, acrylic acid, and to cure under high temperature or ultraviolet irradiation to form an isolation layer structure that blocks external liquid.

[0004] The above-mentioned practice in the industry has the following problems: first, the service life of part of the organic coating material is poorer than that of the capacitor itself. Taking the example of coating epoxy resin on the outer side of the bakelite cover as an isolation layer, in the process of long-time high-temperature load use, the epoxy resin will age and deteriorate and gradually crack and fall off. The gas generated by the volatilization of the electrolyte in the capacitor escapes from the bakelite cover and also produces stress in the inside of the isolation layer to accelerate its cracking and falling off, and the stability is poor. Second, the dispensing process is complex, and the material cost is high. Therefore, by separately installing an oil separation pad or injecting glue to form a sealed isolation layer on the outer surface of the bakelite cover, this structure and mode have the defects of short service life, poor oil resistance and oil resistance sealing effect, complex manufacturing process, etc. INVENTION CONTENTS

[0005] Based on this, it is necessary to provide an efficient oil-resistant sealing cover plate for aluminum electrolytic capacitor, which is formed by pressing the oil-resistant layer on the outer side end face of the substrate layer and the sealing layer on the inner side end face to form a one-piece high-strength and high-sealing composite sealing cover plate.

[0006] The technical problems of the utility model are solved by the following technical solutions:

[0007] An efficient oil-resistant sealing cover plate for aluminum electrolytic capacitor, characterized in that: the sealing cover plate comprises a substrate layer, an oil-resistant layer and a sealing layer; the upper end face of the substrate layer is provided with the oil-resistant layer; the lower end face of the substrate layer is provided with the sealing layer; the substrate layer, the oil-resistant layer and the sealing layer are pressed together to form an integrated plate structure; two through holes are symmetrically arranged on the end face of the sealing cover plate near the middle position; the through holes penetrate the substrate layer, the oil-resistant layer and the sealing layer; metal pins for positive and negative electrode leads are respectively inserted into the two through holes; the upper end of the metal pin protrudes from the surface of the oil-resistant layer and is fixed as the positive and negative electrode lead end; the lower end of the metal pin protrudes from the surface of the sealing layer and is fixed as the positive and negative electrode lead end.

[0008] Preferably, the substrate layer is located in the middle of the stack, the upper end face of the substrate layer is combined with the lower end face of the oil-resistant layer, and the lower end face of the substrate layer is combined with the upper end face of the sealing layer; the substrate layer, the oil-resistant layer and the sealing layer are bonded together by high-temperature and high-pressure pressing to form an integrated structure.

[0009] Preferably, the metal pin comprises a pin cap, a pin body, a gasket and a welding end; the pin cap is arranged at one end of the pin body in the length direction, and the welding end is arranged at the end of the pin body away from the pin cap; the gasket is arranged between the pin cap and the welding end; the pin cap is exposed outside the surface of the oil-resistant layer after the pin body penetrates the through hole; the gasket is located on the outer surface of the sealing layer, and the welding end is exposed through the gasket.

[0010] Preferably, the positive terminal is fixed on one side of the pin cap of the positive metal pin, and the negative terminal is fixed on one side of the pin cap of the negative metal pin.

[0011] Preferably, the positive terminal and the negative terminal are of horn type or bolt type.

[0012] Preferably, the sealing cover plate is applied to horn type aluminum electrolytic capacitor, bolt type aluminum electrolytic capacitor and guide pin type aluminum electrolytic capacitor.

[0013] The advantages and positive effects of this utility model are: a high-efficiency oil-resistant sealing cover for aluminum electrolytic capacitors, which solves the problem of poor oil resistance and oil resistance in existing aluminum electrolytic capacitors. Compared with the prior art, this utility model has the following advantages:

[0014] This invention creates a high-strength, high-sealing composite sealing cover by pressing an oil-resistant layer to the outer end face of a substrate layer and a sealing layer resistant to electrolyte corrosion to the inner end face, thus forming an integrated cover. This sealing cover offers excellent sealing performance, strong oil and corrosion resistance. Aluminum electrolytic capacitors encapsulated with this cover internally prevent electrolyte vaporization and externally prevent oil penetration, ensuring stable operation even in oily environments. This solves the problem of poor oil resistance in existing aluminum electrolytic capacitors, improving safety and stability, and extending their service life. Furthermore, the manufacturing process is simple, easy to operate, and low-cost, meeting the needs of the production field. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0016] Figure 1 This is a schematic cross-sectional view of the sealing cover plate of this utility model.

[0017] Figure 2 This is a three-dimensional view of the sealing cover plate of this utility model.

[0018] Figure 3 This is a three-dimensional structural diagram of the sealing cover plate according to the second embodiment of the present utility model.

[0019] Figure 4 This is a cross-sectional schematic diagram of the sealing cover plate of this utility model applied in an aluminum electrolytic capacitor.

[0020] Explanation of reference numerals: 1. Substrate layer; 2. Oil-resistant layer; 3. Sealing layer; 4. Through hole; 5. Positive terminal; 6. Negative terminal; 7. Conductive metal nail; 8. Outer shell; 9. Element; 10. Positive conductive foil strip; 11. Negative conductive foil strip; 12. Waist structure; 701. Nail head; 702. Nail body; 703. Gasket; 704. Welding end. Detailed Implementation

[0021] The embodiments of this utility model will be further described in detail below with reference to the accompanying drawings: The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this utility model or its application or use. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model. In the description of this utility model, it should be understood that the terms "length," "upper," "lower," "bottom," "inner," "outer," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Example 1

[0022] like Figure 1 As shown, the sealing cover includes a substrate layer 1, an oil-resistant layer 2, and a sealing layer 3; the oil-resistant layer 2 is provided on the upper end surface of the substrate layer 1; the sealing layer 3 is provided on the lower end surface of the substrate layer 1; the adjacent contact surfaces of the substrate layer 1, the oil-resistant layer 2, and the sealing layer 3 are pressed together to form an integral plate structure; two through holes 4 are symmetrically provided near the middle position on the end face of the sealing cover; the through holes 4 penetrate the substrate layer 1, the oil-resistant layer 2, and the sealing layer 3; metal nails 7 for positive electrode lead-out and negative electrode lead-out are respectively inserted into the two through holes 4; the upper end of the metal nail 7 extends out of the surface of the oil-resistant layer 2 and is fixed as the positive and negative electrode lead-out end; the lower end of the metal nail 7 extends out of the surface of the sealing layer 3 and is fixed as the positive and negative electrode lead-in end.

[0023] like Figure 4 As shown, this sealing cover is used for the encapsulation of aluminum electrolytic capacitors. Specifically, the element 9 is hermetically sealed within the inner cavity of the aluminum casing 8 using the sealing cover, and leads out through the positive terminal 5 and the negative terminal 6 to obtain the aluminum electrolytic capacitor. The sealing cover serves two purposes: firstly, it prevents external oil from entering the capacitor's interior, and secondly, it prevents the internal electrolyte from vaporizing and overflowing.

[0024] Aluminum electrolytic capacitors include horn-shaped aluminum electrolytic capacitors, bolt-shaped aluminum electrolytic capacitors, and pin-shaped aluminum electrolytic capacitors. The aluminum electrolytic capacitor in this embodiment is primarily a horn-shaped aluminum electrolytic capacitor. In other embodiments, this sealing cover can also be used in bolt-shaped and pin-shaped aluminum electrolytic capacitors.

[0025] like Figure 1As shown, the substrate layer 1 is a phenolic resin laminate; the oil-resistant layer 2 is an ethylene acrylate rubber compound or hydrogenated nitrile rubber; the sealing layer 3 is ethylene propylene diene monomer (EPDM) rubber; the substrate layer 1 is located in the middle of the laminate, and the upper end face of the substrate layer 1 is superimposed on the lower end face of the oil-resistant layer 2; the lower end face of the substrate layer 1 is superimposed on the upper end face of the sealing layer 3; and they are bonded together under high temperature and pressure to form an integral whole.

[0026] The substrate layer 1, made of phenolic resin laminate, improves the rigidity of the entire sealing cover structure and reduces deformation during encapsulation and under thermal shock. The sealing layer 3 is made of EPDM rubber. The phenolic resin laminate layer and the EPDM rubber layer are integrally molded. After resin synthesis and composite material impregnation, they are stacked and pressed together to form a stable structure with strong adhesion between the two layers, making them difficult to separate and resulting in a robust structure. Based on the integral molding of the phenolic resin laminate layer and the EPDM rubber layer, an ethylene acrylate rubber compound or hydrogenated nitrile rubber is pressed onto the other surface of the phenolic resin laminate layer. This is bonded to the oil-resistant ethylene acrylate rubber compound using an adhesive under high temperature molding, forming an oil-resistant layer 2 on the upper surface of the substrate layer 1, creating a stable, integrated sheet structure.

[0027] The oil-resistant layer 2 and the substrate layer 1 are bonded together. The oil-resistant layer 2 uses a raw rubber system different from EPDM rubber, which is compounded and processed after adding fillers and auxiliary materials, and has strong resistance to mineral oil. After experimental verification, after being immersed in mineral oil and placed in a sealed environment at 105°C for 21 days, the change in Shore hardness is less than ±1, the volume expansion rate is less than 10%, and the insulation resistance is higher than 50GΩ. The oil-resistant layer 2 with this material formulation can effectively isolate the external oil cooling environment, indicating that the oil-resistant rubber layer 2 and the phenolic resin laminate layer, i.e., the substrate layer 1, have strong oil resistance when bonded together.

[0028] EPDM rubber has poor resistance to mineral oil and will rapidly fail when immersed in mineral oil at high temperatures, but it has good resistance to electrolytes. Conversely, the oil-resistant layer 2 used in this invention has good resistance to mineral oil but poor resistance to electrolytes. The structure of this invention uses two layers of different materials that play different roles. The EPDM rubber is in direct contact with the electrolyte, providing corrosion resistance and electrolytic contact, and sealing to prevent electrolyte leakage. The oil-resistant layer 2 is in direct contact with the oil, providing good oil resistance. By leveraging the advantages of both materials and combining them with the rigid structure of the substrate layer 1, this design meets the lifespan requirements of aluminum electrolytic capacitors in oily environments.

[0029] like Figure 1As shown, the further metal nail 7 includes a nail head 701, a nail body 702, a washer 703, and a welding end 704; the nail head 701 is provided at one end of the nail body 702 along its length, and the welding end 704 is provided at the other end of the nail body 702 away from the nail head 701; the washer 703 is sleeved on the nail body 702 between the nail head 701 and the welding end 704; after the nail body 702 passes through the through hole 4, the nail head 701 is exposed on the outer surface of the oil-resistant layer 2; the washer 703 is located on the outer surface of the sealing layer 3, and the welding end 704 is exposed on one side after passing through the washer 703.

[0030] The metal nail 7, consisting of a nail head 701, nail body 702, and welding end 704, is an integrally formed I-shaped structure. In this embodiment, the metal nail 7 is made of aluminum. After the nail body 702 passes through the through hole 4, the nail head 701 protrudes from the outer surface of the oil-resistant layer 2; the nail head 701 and the opposite surface of the oil-resistant layer 2 are in sealing contact. The diameter of the nail head 701 is larger than the diameter of the through hole 4, which serves to fix and lock the positive and negative terminals and the oil-resistant layer 2, improving the stability of the positive and negative terminals. It also prevents the separation between the oil-resistant layer 2 and the substrate layer 1. A welding end 704 is provided at the end away from the nail head 701, and a gasket 703 is located on the outer surface of the sealing layer 3, with the welding end 704 protruding through the gasket 703. The outer diameter of the gasket 703 is larger than the diameter of the through hole 4. The gasket 703 is pressed and fixed with the nail body 702 and the welding end 704. On the one hand, this locks and fixes the metal nail 7 outward, and on the other hand, it locks and fixes the sealing layer 3, preventing the separation between the sealing layer 3 and the substrate layer 1, and further improving the rigidity and sealing performance between the substrate layer 1, the oil-resistant layer 2, and the sealing layer 3. The welding end 704 is used to weld the positive electrode conductive foil strip 10 and the negative electrode conductive foil strip 11 led out from the element 9, so that the metal nail 7 and the element 9 form an electrical connection.

[0031] like Figures 1-4 As shown, further, a positive terminal 5 is fixedly provided on one side of the nail head 701 in the positive terminal metal nail 7, and a negative terminal 6 is fixedly provided on one side of the nail head 701 in the negative terminal metal nail 7.

[0032] Positive terminal 5 and negative terminal 6 serve as the leads of the capacitor. In this embodiment, positive terminal 5 and negative terminal 6 are horn-shaped terminals, and a horn-shaped aluminum electrolytic capacitor is used. Example 2

[0033] In this embodiment, as Figure 3 As shown, the difference between Embodiment 2 and Embodiment 1 is that the positive terminal 5 and the negative terminal 6 are bolt-type terminals; otherwise, they are the same as in Embodiment 1. A nut is provided at one end of the metal nail 7 that protrudes from the surface of the oil-resistant layer 2, and a screw is fitted inside the nut. The sealing cover plate of this embodiment is applied to a bolt-type aluminum electrolytic capacitor. When the bolt-type aluminum electrolytic capacitor is mounted on the circuit board, it is fixed by the combination of the nut and screw on the outside of the sealing cover plate.

[0034] likeFigure 4 As shown, the sealing cover is used in aluminum electrolytic capacitors. Specifically, the sealing cover seals the element 9 inside the outer shell 8 of the aluminum electrolytic capacitor. A waisting structure 12 for sealing and fixing is provided at the contact point between the inner wall of the outer shell 8 and the circumferential side wall of the sealing cover. The sealing cover is fixed by the waisting structure 12, and the substrate layer 1, oil-resistant layer 2, and sealing layer 3 are in full contact with the inner wall of the outer shell 8, further improving the oil resistance.

[0035] The inner cavity of the outer shell 8 is sealed with a component 9, with a positive conductive foil strip 10 and a negative conductive foil strip 11 extending from its ends. The positive and negative conductive foil strips 10 and 11 are connected to the welding end 704 by one of ultrasonic welding, laser welding, resistance welding, or cold welding. After the sealing cover is manufactured, the positive and negative conductive foil strips 10 and 11 in the component 9 are welded to the welding end 703 at one end of the conductive post 7 by one of ultrasonic welding, laser welding, resistance welding, or cold welding, with the metal nail 7 serving as the positive or negative lead-out. This further improves the oil resistance effect.

[0036] After testing, the Snap-in capacitors manufactured by the Bakelite cap of this utility model in Examples 1-2, after being placed in an oven at 105°C with the working voltage applied for 2500 hours, showed an average change rate of capacitance (CAP) of less than 10% and an average change rate of loss tangent (DF) of less than 5%.

[0037] The experimental results from the examples show that the aluminum electrolytic capacitor using this sealing cover maintains a low and stable rate of change in capacitance (CAP) and loss tangent (DF) in a high-temperature oil environment. This indicates that the sealing cover has good sealing performance, strong oil-proof and corrosion-resistant properties. The aluminum electrolytic capacitor sealed with this cover internally prevents electrolyte vaporization and externally blocks oil penetration, ensuring that the internal electrolyte does not vaporize and overflow, and that external oil does not enter. This allows the aluminum electrolytic capacitor to maintain stable operation in oily environments, solving the problem of poor oil resistance and tolerance in existing aluminum electrolytic capacitors. It improves its safety and stability and extends the service life of the aluminum electrolytic capacitor.

[0038] It should be emphasized that the embodiments described in this utility model are illustrative rather than limiting. Therefore, this utility model is not limited to the embodiments described in the specific implementation. Any other implementation methods derived by those skilled in the art based on the technical solutions of this utility model are also within the scope of protection of this utility model.

Claims

1. A high efficient oil resistant sealing cover plate for aluminum electrolytic capacitor, characterized in that: The sealing cover plate comprises a substrate layer, an oil-resistant layer and a sealing layer; the upper end surface of the substrate layer is provided with the oil-resistant layer; the lower end bottom surface of the substrate layer is provided with the sealing layer; the substrate layer, the oil-resistant layer and the sealing layer are adjacent to each other and are pressed together to form an integrally formed plate structure; two through holes are symmetrically arranged on the end surface of the sealing cover plate close to the middle position; the through holes penetrate the substrate layer, the oil-resistant layer and the sealing layer; metal pegs for positive and negative electrode leads are respectively inserted into the two through holes; the upper end of the metal pegs protrudes out of the surface of the oil-resistant layer and is fixed as the positive and negative electrode lead-out end; the lower end of the metal pegs protrudes out of the surface of the sealing layer and is fixed as the positive and negative electrode lead-in end; the metal pegs comprise a peg cap, a peg body, a gasket and a welding end; the peg cap is arranged at one end of the peg body in the length direction, and the welding end is arranged at the end of the peg body away from the peg cap; the peg body between the peg cap and the welding end is sleeved with the gasket; the peg cap is exposed outside the oil-resistant layer after the peg body penetrates through the through hole; the gasket is located on the outer side surface of the sealing layer, and the welding end is exposed through one side of the gasket; the peg cap, the peg body and the welding end of the metal peg are in an integrally formed I-shaped structure; one end of the metal peg protruding out of the surface of the oil-resistant layer is provided with a nut, and the nut is matched with a screw.

2. The high efficient oil-resistant sealing cover plate of aluminum electrolytic capacitor according to claim 1, characterized in that: The substrate layer is located in the middle of the stack, the upper end surface of the substrate layer is combined with the lower end surface of the oil-resistant layer; the lower end surface of the substrate layer is combined with the upper end surface of the sealing layer; and the combination is formed into an integral body through high-temperature and pressure pressing and bonding.

3. The high efficient oil-resistant sealing cover plate of aluminum electrolytic capacitor of claim 1, wherein: The positive terminal is fixed on one side of the peg cap of the metal peg of the positive electrode, and the negative terminal is fixed on one side of the peg cap of the metal peg of the negative electrode.

4. The high efficient oil-resistant sealing cover plate of aluminum electrolytic capacitor according to claim 3, characterized in that: The types of the positive terminal and the negative terminal are horn-shaped terminals or bolt-shaped terminals.

5. The high efficient oil-resistant sealing cover plate of aluminum electrolytic capacitor according to any one of claims 1-4, characterized in that: The sealing cover plate is applied to horn-shaped aluminum electrolytic capacitors, bolt-shaped aluminum electrolytic capacitors and needle-shaped aluminum electrolytic capacitors.

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