Conductive silver paste, chip polymer laminated aluminum capacitor and preparation method of chip polymer laminated aluminum capacitor

Abstract

In order to solve the problems of insufficient bonding force and high resistivity of the existing conductive silver paste, the invention provides the conductive silver paste, which comprises silver powder, a first solvent and acrylic acid modified epoxy resin, and the mass content of free acryloyloxy in the acrylic acid modified epoxy resin is 1-10%. Meanwhile, the invention also discloses a preparation method of the conductive silver paste and a chip polymer laminated aluminum capacitor comprising the conductive silver paste. The conductive silver paste provided by the invention has relatively low resistivity, relatively high bonding strength and high temperature resistance.

Description

Technical Field

[0001] The present invention belongs to the technical field of capacitor materials, and in particular relates to a conductive silver paste, a chip-type polymer laminated aluminum capacitor and a preparation method thereof. Background Art

[0002] High-performance epoxy resin-based conductive silver pastes or adhesives are widely used in high-end sectors such as 5G and new energy photovoltaics due to their chemical properties. However, due to their high reactivity, the main resin in the conductive silver paste requires a curing agent for practical use. The use of curing agents can easily deteriorate the paste or shorten its lifespan, and some can even affect the basic properties of the silver powder. These are all challenges faced in the development of high-performance epoxy resin conductive silver pastes.

[0003] The main problems with the paste in existing application technologies are low adhesion between the silver paste and the underlying substrate after curing and high resistivity (square resistance). Insufficient adhesion will seriously affect the overall impedance of the material, while excessively high resistivity will affect the efficiency of the paste.

[0004] On the other hand, the existing silver paste has the problem of insufficient high temperature resistance. Under high temperature, the resin in the silver paste will accelerate aging, thereby causing the impedance of the silver paste to further increase. Summary of the Invention

[0005] Aiming at the problems of insufficient adhesion and high resistivity of existing conductive silver paste, the present invention provides a conductive silver paste, a chip-type polymer laminated aluminum capacitor and a preparation method thereof.

[0006] The technical solutions adopted by the present invention to solve the above technical problems are as follows:

[0007] In one aspect, the present invention provides a conductive silver paste comprising silver powder, a first solvent and an acrylic acid-modified epoxy resin, wherein the mass content of free acryloxy groups in the acrylic acid-modified epoxy resin is 1% to 10%.

[0008] Optionally, the conductive silver paste includes the following components by weight:

[0009] 30-80 parts of silver powder, 10-45 parts of the first solvent and 3-10 parts of acrylic acid-modified fluorine-containing epoxy resin.

[0010] Optionally, the acrylic modified epoxy resin is obtained by copolymerizing an acrylic monomer and an epoxy resin, and the mass ratio of the acrylic monomer to the epoxy resin is (30-60): (70-40).

[0011] Optionally, the epoxy resin includes one or more of bisphenol A epoxy resin and bisphenol F epoxy resin.

[0012] Optionally, the acrylic monomer includes one or more of methyl methacrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, hexafluorobutyl acrylate, hexafluorobutyl methacrylate, dodecafluoroheptyl methacrylate, lauryl acrylate, octadecyl acrylate, methacrylate, ethyl acetoacetate methacrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, γ-methacryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltris(β-trimethoxyethoxysilane).

[0013] Optionally, the silver powder comprises the following components by weight: 25 to 50 parts of flaky silver powder and 5 to 30 parts of nano-spherical silver, wherein the melting point of the nano-spherical silver is less than 150°C.

[0014] Optionally, the silver powder is coated with oleic acid or stearic acid.

[0015] Optionally, the first solvent includes one or more substances selected from esters, ethers and ketones.

[0016] On the other hand, the present invention provides a method for preparing the conductive silver paste as described above, comprising the following steps:

[0017] Adding an acrylic monomer and an epoxy resin into a second solvent, stirring, and adding a accelerator dropwise to react to obtain an acrylic modified epoxy resin, and controlling the mass content of free acryloyloxy groups in the acrylic modified epoxy resin to 1% to 10% by distillation and / or ion exchange;

[0018] The acrylic modified epoxy resin, silver powder and the first solvent are dispersed and mixed to obtain a conductive silver paste.

[0019] On the other hand, the present invention provides a chip-type polymer laminated aluminum capacitor, including a capacitor core, wherein the capacitor core includes multiple capacitor monoliths, the outer layer of the capacitor monoliths is a conductive silver layer, and the multiple capacitor monoliths are interconnected and combined by the conductive silver layer, and the conductive silver layer is obtained by curing the conductive silver paste described above.

[0020] According to the conductive silver paste provided by the present invention, an acrylic acid-modified epoxy resin is used as the main resin in the conductive silver paste. The inventors have found through a large number of experiments that in the conductive silver paste, by controlling the mass percentage of free acryloyloxy groups in the conductive silver paste to be between 1% and 10%, the cured conductive silver paste has higher bonding strength and lower resistivity. It is speculated that this is because the free acryloyloxy groups come from the unreacted acrylic monomers in the acrylic acid-modified epoxy resin and act as active diluents for the conductive silver paste. During the curing stage, when a certain amount of acryloyloxy groups react with epoxy and hydroxyl groups, an interpenetrating network polymer is formed, which improves the compatibility with silver powder, can effectively prevent the silver powder from settling, reduce the resistivity of the conductive silver paste, and also improve the bonding strength and high-temperature resistance of the conductive silver paste after curing. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0022] An embodiment of the present invention provides a conductive silver paste, comprising silver powder, a first solvent, and an acrylic acid-modified epoxy resin, wherein the mass content of free acryloxy groups in the acrylic acid-modified epoxy resin is 1% to 10%.

[0023] The conductive silver paste uses an acrylic modified epoxy resin as the main resin in the conductive silver paste. The inventors have found through a large number of experiments that in the conductive silver paste, by controlling the mass percentage of free acryloyloxy groups in the conductive silver paste to be between 1% and 10%, the cured conductive silver paste has higher bonding strength and lower resistivity. It is speculated that this is because the free acryloyloxy groups come from the unreacted acrylic monomers in the acrylic modified epoxy resin and act as active diluents for the conductive silver paste. During the curing stage, when a certain amount of acryloyloxy groups react with epoxy and hydroxyl groups, an interpenetrating network polymer is formed, which improves the compatibility with silver powder, can effectively prevent the silver powder from settling, reduce the resistivity of the conductive silver paste, and also improve the bonding strength and high temperature resistance of the conductive silver paste after curing.

[0024] In some embodiments, the conductive silver paste includes the following components by weight:

[0025] 30-80 parts of silver powder, 10-45 parts of the first solvent and 3-10 parts of acrylic acid-modified fluorine-containing epoxy resin.

[0026] Specifically, the weight ratio of the silver powder can be 30 parts, 38 parts, 41 parts, 44 parts, 56 parts, 65 parts, 68 parts, 71 parts, 74 parts, 76 parts, 78 parts, 79 parts or 80 parts. The weight ratio of the first solvent can be 10 parts, 11 parts, 14 parts, 16 parts, 20 parts, 21 parts, 24 parts, 26 parts, 30 parts, 38 parts, 41 parts, 44 parts or 45 parts. The weight ratio of the acrylic modified fluorine-containing epoxy resin can be 3 parts, 3.2 parts, 3.5 parts, 3.8 parts, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, 7.8 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts or 10 parts.

[0027] In some embodiments, the acrylic modified epoxy resin is obtained by copolymerizing an acrylic monomer and an epoxy resin, and the mass ratio of the acrylic monomer to the epoxy resin is (30-60): (70-40).

[0028] During the copolymerization of the acrylic monomer and the epoxy resin, the acrylic monomer and the ring-opened epoxy resin are cross-linked and polymerized. By controlling the degree of reaction, part of the acrylic monomer forms oligomers or does not undergo polymerization reaction, and free acryloyloxy groups are formed in the acrylic-modified epoxy resin. Specifically, the macromolecular polymer and the free acryloyloxy groups in the acrylic-modified epoxy resin can be separated by membrane separation, the portion that does not pass through the filter membrane is dried to obtain the mass of the macromolecular polymer, and the portion that passes through the filter membrane is tested by GC-MS or LC-MS to determine the mass content of the free acryloyloxy groups in the acrylic-modified epoxy resin.

[0029] In some embodiments, the epoxy resin includes one or more of bisphenol A epoxy resin and bisphenol F epoxy resin.

[0030] In some embodiments, the acrylic monomer includes one or more of methyl methacrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, hexafluorobutyl acrylate, hexafluorobutyl methacrylate, dodecafluoroheptyl methacrylate, lauryl acrylate, octadecyl acrylate, methacrylate, ethyl acetoacetate methacrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropyltris(β-trimethoxyethoxysilane).

[0031] In some embodiments, the silver powder comprises the following components by weight: 25 to 50 parts of flaky silver powder and 5 to 30 parts of nano-spherical silver, wherein the melting point of the nano-spherical silver is less than 150°C.

[0032] The composite use of flaky silver powder and nano-spherical silver in the conductive silver paste can effectively reduce the resistivity of the product itself, especially the use of low-melting-point nano-spherical silver, which can fill the gaps between different flaky silver powders through melting changes during the solidification process to form electrical connection channels, further reducing the interfacial impedance of the conductive silver paste during use.

[0033] In some embodiments, the flaky silver powder has a D50 particle size of 1 to 5 microns and a tap density of 2 g / cm 3 -5g / cm 3 The flake ratio is more than 10% (observed by scanning electron microscopy). The D50 particle size of the nano-spherical silver is 20 to 100 nanometers, and the tap density is 2 g / cm 3 -8g / cm 3 , nanostructure accounts for more than 50%, and the melting point is <150℃.

[0034] In some embodiments, the silver powder is coated with oleic acid or stearic acid.

[0035] The inorganic silver powder is coated with oleic acid or stearic acid to cover the periphery of the inorganic silver powder with an organic layer, which can effectively improve the affinity between the silver powder and the acrylic modified epoxy resin and improve the dispersion uniformity of the silver powder in the conductive silver paste.

[0036] In some embodiments, the first solvent includes one or more substances selected from esters, ethers, and ketones.

[0037] In a preferred embodiment, the first solvent is selected from one or more of ethyl acetate, propyl acetate, butyl acetate, ethyl lactate, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, DBE, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, and 3-methoxyperfluorohexane.

[0038] Another embodiment of the present invention provides a method for preparing the conductive silver paste as described above, comprising the following steps:

[0039] Adding an acrylic monomer and an epoxy resin into a second solvent, stirring, and adding a accelerator dropwise to react to obtain an acrylic modified epoxy resin, and controlling the mass content of free acryloyloxy groups in the acrylic modified epoxy resin to 1% to 10% by distillation and / or ion exchange;

[0040] The acrylic modified epoxy resin, silver powder and the first solvent are dispersed and mixed to obtain a conductive silver paste.

[0041] The mass content of free acryloyloxy groups in the acrylic-modified epoxy resin is determined by the degree of copolymerization. The more fully the copolymerization proceeds, the lower the mass content of free acryloyloxy groups. Therefore, in actual operation, an acrylic-modified epoxy resin with a certain content of acryloyloxy groups can be obtained by controlling the reaction time and temperature. When the acryloyloxy group content in the acrylic-modified epoxy resin is too high, the acryloyloxy group content can be reduced by distillation and / or ion exchange treatment. Specifically, distillation can remove some monomers or oligomers with lower boiling points from the resin system, thereby reducing the acryloyloxy group content. Similarly, ion exchange can reduce the number of charged monomers in the acrylic-modified epoxy resin, thereby reducing the acryloyloxy group content.

[0042] In some embodiments, in the copolymerization reaction of acrylic monomer and epoxy resin, the reaction temperature is 50° C. to 120° C., and the reaction time is 5 to 24 hours.

[0043] In some embodiments, the second solvent includes one or more selected from esters, ethers, and ketones.

[0044] In a preferred embodiment, the second solvent is selected from one or more of ethyl acetate, propyl acetate, butyl acetate, ethyl lactate, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, diethylene glycol methyl ether acetate, diethylene glycol ethyl ether acetate, diethylene glycol butyl ether acetate, propylene glycol methyl ether acetate, DBE, methyl perfluorobutyl ether, ethyl perfluorobutyl ether, and 3-methoxyperfluorohexane.

[0045] In some embodiments, the accelerator includes one or more of amines, amides, anhydrides, polyphenols, and polymeric thiols.

[0046] In a preferred embodiment, the accelerator is selected from amine compounds. In a more preferred embodiment, the accelerator includes one or more of polyamide compounds, aliphatic amine compounds, aromatic amine compounds, alicyclic amine compounds, polyether amines and imidazole compounds.

[0047] In some embodiments, the imidazole compound includes one or more of 1-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-cyano-ethyl-4-methylimidazole, and 1-cyanoethyl-2-phenylimidazole.

[0048] Another embodiment of the present invention provides a chip-type polymer laminated aluminum capacitor, including a capacitor core, wherein the capacitor core includes multiple capacitor monoliths, the outer layer of the capacitor monoliths is a conductive silver layer, and the multiple capacitor monoliths are interconnected and combined by the conductive silver layer, and the conductive silver layer is obtained by curing the conductive silver paste described above.

[0049] Due to the use of the conductive silver paste described above, the individual capacitor chips of the chip-type polymer laminated aluminum capacitor have strong bonding strength, low equivalent series resistance and excellent high-temperature stability.

[0050] Another embodiment of the present invention provides a packaging method for the above-mentioned chip-type polymer laminated aluminum capacitor, comprising the following steps:

[0051] Obtain a single sheet of aluminum foil having a surface impregnated with a conductive polymer; impregnate it with a conductive carbon slurry (such as SuC-203) through a dipping process; impregnate it with the conductive silver paste described above through a dipping process; cut the single sheet and laminate it into layers through hot pressing; plastic-encapsulate the laminated product; and test it to obtain a chip-type polymer laminated aluminum capacitor.

[0052] The present invention is further described below with reference to the following examples.

[0053] Example 1

[0054] This embodiment is used to illustrate the conductive silver paste and its preparation method disclosed in the present invention, including the following operations:

[0055] 50 parts of methacrylic acid and 100 parts of a commercially available epoxy resin with an epoxy equivalent weight of 150 g / eq were added to a mixed solvent of hydrofluoroether and ethylene glycol monobutyl ether and stirred in a 70°C oil bath for 60 minutes until completely dissolved. Then, a mixture of 1.5 parts of 1-methylimidazole and 20 parts of diethylene glycol butyl ether acetate was dripped into the reaction flask over 20 minutes. The liquid temperature was controlled not to exceed 85°C during the addition process. After the addition was complete, the liquid temperature was controlled to be between 80-82°C and the reaction was continued for 12 hours. During the reaction, the viscosity of the system continued to increase. After the reaction was completed, a transparent product was obtained, namely an acrylic acid-modified epoxy resin. The obtained acrylic acid-modified epoxy resin was distilled and ion-exchanged, and the mass content of free acryloyloxy groups was controlled to 5.3% by controlling the distillation temperature and time as well as the number of ion exchanges.

[0056] Weigh 5 parts of the treated acrylic modified epoxy resin, 50 parts of flaky silver powder (D50 is 1 micron), and 5 parts of nano-sphere silver (D50 is 80 nanometers). The melting point of nano-sphere silver is 135°C. Add 15 parts of ethylene glycol monobutyl ether and 25 parts of diethylene glycol ethyl ether acetate respectively, add them to a double planetary mixer, control the temperature between 20 and 30°C, and stir for 4 hours. Stir evenly to form a conductive silver paste.

[0057] Example 2

[0058] This example is used to illustrate the conductive silver paste and its preparation method disclosed in the present invention, and includes most of the operations in Example 1, except that:

[0059] The mass content of free acryloyloxy groups was controlled to 3.1% by controlling the distillation temperature and time as well as the number of ion exchanges.

[0060] Example 3

[0061] This example is used to illustrate the conductive silver paste and its preparation method disclosed in the present invention, and includes most of the operations in Example 1, except that:

[0062] The mass content of free acryloyloxy groups was controlled to 5.7% by controlling the distillation temperature and time as well as the number of ion exchanges.

[0063] Example 4

[0064] This example is used to illustrate the conductive silver paste and its preparation method disclosed in the present invention, and includes most of the operations in Example 1, except that:

[0065] The mass content of free acryloyloxy groups was controlled to 7.7% by controlling the distillation temperature and time as well as the number of ion exchanges.

[0066] Example 5

[0067] This example is used to illustrate the conductive silver paste and its preparation method disclosed in the present invention, and includes most of the operations in Example 1, except that:

[0068] The mass content of free acryloyloxy groups was controlled to 9.5% by controlling the distillation temperature and time as well as the number of ion exchanges.

[0069] Example 6

[0070] This example is used to illustrate the conductive silver paste and its preparation method disclosed in the present invention, and includes most of the operations in Example 1, except that:

[0071] The mass content of free acryloyloxy groups was controlled to 6.3% by controlling the distillation temperature and time as well as the number of ion exchanges.

[0072] Example 7

[0073] This example is used to illustrate the conductive silver paste and its preparation method disclosed in the present invention, and includes most of the operations in Example 1, except that:

[0074] Micronized silver spheres were used to replace the nano-sized silver spheres in Example 1. The D50 particle size of the micronized silver spheres was 1.2 μm and the melting point was >300° C.

[0075] Comparative Example 1

[0076] This comparative example is used to illustrate the conductive silver paste and preparation method thereof disclosed in the present invention, and includes most of the operations in Example 1, except that:

[0077] The acrylic acid-modified epoxy resin in Example 1 was replaced by a commercially available epoxy resin.

[0078] Comparative Example 2

[0079] This comparative example is used to illustrate the conductive silver paste and preparation method thereof disclosed in the present invention, and includes most of the operations in Example 1, except that:

[0080] The acrylic acid-modified epoxy resin in Example 1 was replaced by a commercially available acrylic resin (with a free acryloyloxy mass content of 23.5%).

[0081] Comparative Example 3

[0082] This comparative example is used to illustrate the conductive silver paste and preparation method thereof disclosed in the present invention, and includes most of the operations in Example 1, except that:

[0083] The mass content of free acryloyloxy groups was controlled to 19.3% by controlling the distillation temperature and time as well as the number of ion exchanges.

[0084] Performance Testing

[0085] The conductive silver paste prepared above was subjected to the following performance tests:

[0086] (1) Determination of free acryloyloxy content: The prepared acrylic acid-modified epoxy resin is subjected to membrane separation technology, and the portion that passes through the filter membrane is subjected to GC-MS or LC-MS testing.

[0087] (2) Fineness test: Scraper fineness determination method (reference standard: GB / T 6753.1): Use a pipette to take a sample of the conductive silver paste and drop it into the deepest part of the scraper chute. Place the scraper horizontally at the top of the scraper, with the edge of the scraper perpendicular to the scraper surface. Pull the sample from the deep end of the chute to the shallow end at a constant speed within 5 seconds. Within 5 seconds, observe the minimum scale line where the particles are evenly exposed in the chute. This value is the fineness of the silver paste.

[0088] (3) Adhesion test: 100-grid method: Apply a 30mm×30mm rectangular coating on a glass slide and dry it at 180℃ for 20min. Prepare five samples and use a 100-grid knife to draw 10×10 (100) 1mm×1mm small grids on the surface of the test sample. Each line should be deep enough to reach the bottom layer of the coating. Use a brush to clean the debris in the test area. Use 3M600# tape to firmly stick to the small network to be tested and wipe the tape vigorously with an eraser to increase the contact area and strength between the tape and the test area. Grab one end of the tape with your hand and quickly tear off the tape in the vertical direction (90 degrees).

[0089] (4) Resistivity test: Four-probe test method: After applying silver paste on a glass slide, bake it in a 150°C oven for 60±2 min to form a silver film with a thickness of 20±2 μm. Select the resistivity mode of the RTS-9 dual-electric four-probe test system to measure the resistivity.

[0090] (5) Thermal Weight Loss Test: Weigh an appropriate amount of conductive silver paste onto a 10 cm diameter aluminum plate and bake it in a 150°C oven for 60 min. Then bake it in a 270°C oven for 10 min. Record the weight before and after baking.

[0091] The test results are entered in Table 1.

[0092] Table 1

[0093]

[0094] It can be seen from the test results in Table 1 that the conductive silver paste prepared by the preparation method provided by the present invention has high adhesion, low resistivity and high high-temperature stability, and can effectively improve the electrochemical performance of the chip-type polymer laminated aluminum capacitor.

[0095] From the test results of Examples 1 to 6 and Example 7, it can be seen that the use of low-melting-point nano-spherical silver can reduce the resistivity of the conductive silver paste compared to micron-spherical silver, indicating that low-melting-point nano-spherical silver can form bridges between flaky silver powders and reduce the impedance of the conductive silver paste.

[0096] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A conductive silver paste, characterized in that: The invention comprises silver powder, a first solvent and an acrylic acid modified epoxy resin, wherein the mass content of free acryloxy groups in the acrylic acid modified epoxy resin is 1% to 10%.

2. The conductive silver paste according to claim 1, characterized in that The conductive silver paste comprises the following components by weight: 30-80 parts of silver powder, 10-45 parts of the first solvent and 3-10 parts of acrylic acid-modified fluorine-containing epoxy resin.

3. The conductive silver paste according to claim 1, characterized in that The acrylic modified epoxy resin is obtained by copolymerizing an acrylic monomer and an epoxy resin, and the mass ratio of the acrylic monomer to the epoxy resin is (30-60): (70-40).

4. The conductive silver paste according to claim 1, characterized in that The epoxy resin includes one or more of bisphenol A epoxy resin and bisphenol F epoxy resin.

5. The conductive silver paste according to claim 1, characterized in that The acrylic monomers include one or more of methyl methacrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, hexafluorobutyl acrylate, hexafluorobutyl methacrylate, dodecafluoroheptyl methacrylate, lauryl acrylate, octadecyl acrylate, methacrylate, ethyl acetoacetate methacrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, γ-methacryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltris(β-trimethoxyethoxysilane).

6. The conductive silver paste according to claim 1, characterized in that The silver powder comprises the following components by weight: 25 to 50 parts of flaky silver powder and 5 to 30 parts of nano-spherical silver, wherein the melting point of the nano-spherical silver is less than 150°C.

7. The conductive silver paste according to claim 1, characterized in that The silver powder is coated with oleic acid or stearic acid.

8. The conductive silver paste according to claim 1, characterized in that The first solvent includes one or more substances selected from esters, ethers and ketones.

9. The method for preparing a conductive silver paste according to any one of claims 1 to 8, wherein: The following steps are included: Adding an acrylic monomer and an epoxy resin into a second solvent, stirring, and adding a accelerator dropwise to react to obtain an acrylic modified epoxy resin, and controlling the mass content of free acryloyloxy groups in the acrylic modified epoxy resin to 1% to 10% by distillation and / or ion exchange; The acrylic modified epoxy resin, silver powder and the first solvent are dispersed and mixed to obtain a conductive silver paste.

10. A chip-type polymer laminated aluminum capacitor, characterized in that: The invention comprises a capacitor core, wherein the capacitor core comprises a plurality of capacitor monoliths, wherein the outer layer of the capacitor monoliths is a conductive silver layer, and the plurality of capacitor monoliths are interconnected and combined by the conductive silver layer, wherein the conductive silver layer is obtained by curing the conductive silver paste according to any one of claims 1 to 8.

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