High thixotropic glue solution for solid-state battery insulation rubber frame, preparation method and application thereof

Abstract

The application provides a high thixotropy glue liquid for a solid-state battery insulating rubber frame and a preparation method and application thereof, and relates to the technical field of all-solid-state batteries. The high thixotropy glue liquid for the solid-state battery insulating rubber frame comprises 9-95% insulating fillers, 3-90% low-polarity dispersants and 1-40% resins; wherein the resins are non-polar, low-polarity or amphiphilic polymers dissolved in the dispersants. The glue liquid has a static viscosity higher than 5x10 4 mPa·s, and under the action of a shear rate not higher than 100 s ‑1 , the viscosity can be reduced to below 10 4 mPa·s, so that the high thixotropy of the slurry is realized.

Description

Technical Field

[0001] This invention relates to the field of all-solid-state battery technology, and more specifically, to a highly thixotropic adhesive liquid for insulating frames of solid-state batteries, its preparation method, and its application. Background Technology

[0002] With the development of transportation electrification and the widespread use of high-performance electronic devices, lithium-ion batteries are becoming increasingly indispensable in people's daily lives. However, traditional liquid lithium-ion batteries contain flammable and volatile organic electrolytes, posing serious safety risks. Furthermore, by-reaction products generated during battery cycling can easily cause crosstalk through the electrolyte, leading to capacity decay and shortened battery life. Therefore, using non-flammable solid electrolytes to replace organic electrolytes can not only improve battery safety but also reduce the impact of electrochemical by-products on battery life.

[0003] In the fabrication of all-solid-state batteries, stacking and pressing the battery components is a crucial step in achieving battery densification and reducing internal resistance. However, the overhang design of the battery itself can cause high shear stress on the solid electrolyte layer near the positive electrode edge under high pressure (>100 MPa), increasing the risk of electrolyte layer rupture and potentially leading to a short circuit and reduced production yield. Therefore, coating the positive electrode edge with a U-shaped insulating frame to eliminate the adverse effects of the overhang design is a vital part of all-solid-state battery manufacturing.

[0004] Existing adhesive frame materials are mainly divided into two categories: one is polymerizable small molecule or oligomer systems (such as cyanoacrylate, acrylic resin, epoxy resin, etc., as patent CN121618069 A, CN121123419A), which have low viscosity, are prone to leakage and overflow during the coating process, and lack thixotropy after curing, making it difficult to achieve high-precision and high-conformity coating patterns; the other is high-polarity polymer systems (such as polyethylene oxide, polyvinylidene fluoride, polyacrylic acid, polyvinyl alcohol, etc., as patent CN121355180A), which have a certain viscosity, but cannot be dissolved in low-polarity solvents, and their polar groups are prone to side reactions with solid electrolytes such as sulfides and halides, leading to increased interfacial resistance and electrolyte degradation. In addition, existing high-viscosity resin systems (such as hot melt adhesives, polyimide, polyurethane, etc., such as patent CN121123419A) have low molecular weights, making it difficult to form a dynamic and reversible physical cross-linking network and lacking thixotropy. Polyimide has no hydrogen bonds or is amphiphilic, and its low molecular weight makes it difficult to generate a dynamic physical cross-linking network, thus failing to form high thixotropy and failing to meet the dual requirements of static leak prevention and dynamic flowability.

[0005] In summary, existing frame materials still have the following problems: ① The components used to prepare the frame react with the solid electrolyte; ② The viscosity of the existing system is not conducive to frame coating: Systems that can polymerize small molecules or low molecular weight resins have low static viscosity, which can lead to leakage at the outlet during coating and overflow of the shape after coating; some resin systems have sufficient static viscosity, but if they lack thixotropy (i.e., low viscosity reduction after shearing), there will be missing coating parts, incomplete shapes, uneven coating thickness, and uneven coating surfaces. Therefore, there is an urgent need to develop a frame material that is compatible with solid electrolytes, has high thixotropy, and is suitable for various high-precision coating methods. Summary of the Invention

[0006] The inventors discovered that for solid-state batteries, electrolyte materials must be added to the electrodes to ensure ion transport. However, commonly used solid electrolytes (such as sulfides and halides) are sensitive to polar groups; therefore, the coating process requires the use of low-polarity or non-polar dispersants (solvents). Resins containing a large number of polar groups cannot dissolve in non-polar solvents; therefore, resin materials with low polarity, non-polarity, or amphiphilic properties must be selected. The high-thixotropic adhesive solution of this application uses low-polarity, non-polarity, or amphiphilic resin materials that can dissolve in low-polarity, high-flash-point solvents, ensuring the stability of the adhesive frame preparation system and the solid electrolyte. The insulating filler, resin, and dispersant components can form non-covalent interactions themselves and between components. The resin material achieves high thixotropy of the slurry through amphiphilic, hydrogen bond, or high molecular weight polymer molecular chain interactions (all three interactions exist statically but are weakened or even eliminated by external forces), ensuring the integrity of the coated shape.

[0007] The first aspect of the present invention provides a highly thixotropic adhesive for insulating frames of solid-state batteries, wherein, by mass fraction, the highly thixotropic adhesive for insulating frames of solid-state batteries comprises 9% to 95% insulating filler, 3% to 90% low polarity dispersant and 1% to 40% resin; The resin is a nonpolar, low-polar, or amphiphilic polymer that is soluble in the low-polarity dispersant.

[0008] Optionally, by mass fraction, the high thixotropic adhesive for solid-state battery insulating frames comprises 40%-80% insulating filler, 20%-50% low-polarity dispersant, and 1%-30% resin.

[0009] Optionally, by mass fraction, the high thixotropic adhesive for solid-state battery insulating frames comprises 60%-75% insulating filler, 25%-40% low-polarity dispersant, and 1%-20% resin.

[0010] Optionally, the viscosity of the high thixotropic adhesive is higher than 5×10⁻⁶. 4 mPa•s, while the shear rate is not higher than 100 s-1 Under shear stress, the viscosity can be reduced to 10. 4 mPa·s or less.

[0011] Optionally, the low-polarity dispersant has a flash point >60℃, a boiling point >60℃, and a dielectric constant <5.5.

[0012] Optionally, the low-polarity dispersant is any one or more of thiol, diphenyl ether, butyl benzoate, dodecane, tetradecane, hexadecane, butyl hexanoate, hexyl hexanoate, butyl octanoate, diethyl adipate, or dipropylene glycol methyl ether.

[0013] Optionally, the low-polarity dispersant is any one or more of butyl hexanoate, hexyl hexanoate, butyl octanoate, or diethyl adipate.

[0014] Optionally, the low-polarity dispersant is composed of butyl hexanoate and butyl octanoate in a mass ratio of 10:(1-10). For example, the low-polarity dispersant can be a compound composed of any point value or any range between two points of butyl hexanoate and butyl octanoate in a mass ratio of 10:1, 10:2, 10:3, 10:4, 10:5, 10:6, 10:7, 10:8, 10:9 or 10:10.

[0015] Optionally, the low-polarity dispersant is composed of trimethylbenzene and hexadecane in a mass ratio of 1:(1-10). For example, the low-polarity dispersant can be a compound composed of any point value or any range between two points of trimethylbenzene and hexadecane in a mass ratio of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0016] Optionally, the low-polarity dispersant is composed of dodecane and butyl hexanoate in a mass ratio of 1:(1-20). For example, the low-polarity dispersant can be a compound composed of any point value or any range between two points of dodecane and butyl hexanoate in a mass ratio of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20.

[0017] Optionally, the low-polarity dispersant is composed of butyl hexanoate, hexyl hexanoate, and butyl octanoate in a mass ratio of 10:(1-5):(1-10). For example, the low-polarity dispersant can be composed of butyl hexanoate, hexyl hexanoate, and butyl octanoate in mass ratios of 10:1:1, 10:1:2, 10:1:3, 10:1:4, 10:1:5, 10:1:6, 10:1:7, 10:1:8, 10:1:9, 10:1:10, 10:2:1, 10:2:2, 10:2:3, 10:2:4, 10:2:5, 10:2:6, 10:2:7, 10:2:8, 10:2:9, 10:2:10, 10:3:1, 10:3:2, 10:3:3, 10:3:4, 10: A compound consisting of any point value or a range of values ​​between any two points in the ratios 3:5, 10:3:6, 10:3:7, 10:3:8, 10:3:9, 10:3:10, 10:4:1, 10:4:2, 10:4:3, 10:4:4, 10:4:5, 10:4:6, 10:4:7, 10:4:8, 10:4:9, 10:4:10, 10:5:1, 10:5:2, 10:5:3, 10:5:4, 10:5:5, 10:5:6, 10:5:7, 10:5:8, 10:5:9, or 10:5:10.

[0018] Optionally, the resin is an amphiphilic polymer, a polymer containing hydrogen bond donors or acceptors and soluble in a low-polarity dispersant, or a polymer with a weight-average molecular weight of not less than 5 × 10⁻⁶. 5 Any one or more of the following high molecular weight linear elastomers with a weight-average molecular weight (g / mol): g / mol. Optionally, the weight-average molecular weight of the high molecular weight linear elastomer can be 5 × 10⁻⁶ g / mol. 5 -10 6 g / mol.

[0019] Optionally, the amphiphilic polymer is any one or more of hydrophobic modified cellulose, hydrophobic modified chitin, hydrophobic modified chitosan, or hydrophobic modified alginate. The structural formula of hydrophobically modified cellulose is as follows: ; The structural formula of hydrophobically modified chitin is as follows: ; The structural formula of hydrophobically modified chitosan is as follows: ; The structural formula of hydrophobically modified alginate is as follows: ; In the amphiphilic polymer, R is independently selected from any one or more of -W, -O=CX, -Si-Y, and -NH-Z, W, X, Y, and Z are any one of alkyl or halogen groups, and n is an integer not less than 10.

[0020] Optionally, the halogen group can be any one of Cl, Br, or I.

[0021] Optionally, the alkyl group can be a C1-C10 alkyl group. For example, the alkyl group can be any one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, and tert-butyl.

[0022] Cellulose, chitin, chitosan, and alginate contain numerous polar groups (hydroxyl -OH, amino -NH2). Direct use of these substances not only causes them to react with the solid electrolyte within the electrode but also limits the resin's solubility in the dispersant. This application performs hydrophobic modification on cellulose, chitin, chitosan, and alginate, respectively. This modification improves the solubility of chitin, chitosan, and alginate in low-polarity dispersants, enhances their amphiphilicity (both solubilizing and hydrophobic properties), ensures their compatibility with the solid electrolyte in the electrode, and maintains the thixotropic properties of the slurry. The modification reaction formula is as follows (taking hydrophobically modified cellulose with R = -C2H5 as an example):

[0023]

[0024] Optionally, the polymer containing hydrogen bond donors or acceptors and soluble in the dispersant is any one or more of modified polyacrylic acid, modified polyurethane, modified polyvinylidene fluoride, or block polymers containing repeating units of both modified polyacrylic acid and modified polyurethane. The modified polyacrylic acid structure is as follows: ; The structural formula of modified polyurethane is :; The structural formula of modified polyvinylidene fluoride is: or ; In the polymer containing hydrogen bond donors or acceptors and dissolved in a dispersant, R is independently selected from any one or more of -V, -OW, -O=CX, -Si-Y, and -NH-Z, where V, W, X, Y, and Z are alkyl or halogen groups; and m and n are integers not less than 10.

[0025] Optionally, the halogen group can be any one of Cl, Br, or I. The alkyl group can be a C1-C10 alkyl group. For example, the alkyl group can be any one of methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl.

[0026] In this application, polyacrylic acid, polyurethane, and polyvinylidene fluoride are modified respectively. By modifying polar groups, their solubility in low-polarity solvents is improved, ensuring their compatibility with the solid electrolyte in the electrode. The modification reaction formula is as follows (taking modified polyacrylic acid with R as -C2H5 as an example): , Optionally, the high molecular weight linear elastomer is any one or more of hydrogenated styrene-butadiene rubber, hydrogenated nitrile rubber, polyolefin elastomer, hydrogenated styrene-isoprene-styrene block copolymer, hydrogenated styrene-ethylene-butene-styrene block copolymer, and hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer. Wherein, i, l, m, n, x, and y are integers.

[0027] The structural formula of hydrogenated styrene-butadiene rubber is: ; The structural formula of hydrogenated nitrile butadiene rubber is: ; The structural formula of polyolefin elastomer is ; The structural formula of the hydrogenated styrene-isoprene-styrene block copolymer is as follows: ; The structural formula of the hydrogenated styrene-ethylene-butene-styrene block copolymer is: ; The structural formula of the hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer is: .

[0028] Optionally, the resin is a mixture of hydrogenated styrene-butadiene rubber and hydrogenated polyolefin elastomer in a mass ratio of 1:(1-5). For example, the resin can be a mixture of hydrogenated styrene-butadiene rubber and hydrogenated polyolefin elastomer in any point value or range between any two points in a mass ratio of 1:1, 1:2, 1:3, 1:4 or 1:5.

[0029] Optionally, the resin is a mixture of hydrogenated styrene-ethylene-butene-styrene block copolymer and hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer in a mass ratio of 1:(1-20). For example, the resin can be a mixture of any point value or any range between any two points of hydrogenated styrene-ethylene-butene-styrene block copolymer and hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer in a mass ratio of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20.

[0030] Optionally, the resin is a mixture of hydrogenated nitrile rubber, hydrogenated styrene-isoprene-styrene block copolymer, and hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer in a mass ratio of 1:(1-20):(1-20). For example, the resin can be hydrogenated nitrile rubber, hydrogenated styrene-isoprene-styrene block copolymer, or hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer in mass ratios of 1:1:1, 1:1:2, 1:1:3, 1:1:4, 1:1:5, 1:1:6, 1:1:7, 1:1:8, 1:1:9, 1:1:10, 1:1:11, 1:1:12, 1:1:13, 1:1:14, 1:1:15, 1:1:16, 1:1:17, 1:1:18, 1:1:19, 1:1:20, 1:2:1, 1:2:2, 1:2:3, 1:2:4, 1:2:5, and 1:2:6. 1:2:7, 1:2:8, 1:2:9, 1:2:10, 1:2:11, 1:2:12, 1:2:13, 1:2:14, 1:2:15, 1:2:16, 1:2:17, 1:2:18, 1:2:19, 1:2:20, 1:3:1, 1:3:2, 1:3:3, 1:3:4, 1:3:5, 1:3:6, 1:3:7, 1:3:8, 1:3:9, 1:3:10, 1:3:11, 1:3:12, 1:3:13, 1:3:14, 1:3:15, 1:3:16, 1:3:17, 1:3:18, 1:3:19, 1:3:20, 1:4 :1、1:4:2、1:4:3、1:4:4、1:4:5、1:4:6、1:4:7、1:4:8、1:4:9、1:4:10、1:4:11、1:4:12、1:4:13、1:4:14、1:4:15、1:4:17、1:4:18、1:4:19、1:4:20、1:5:1、1:5:2、1:5:3、1:5:4、1:5:5、1:5:6、1:5:7、1:5:8、1:5:9、1:5:10、1:5:11、1:5:12、1:5:13、1:5:14、1:5:15、1:5:16、1:5:1 7, 1:5:18, 1:5:19, 1:5:20, 1:6:1, 1:6:2, 1:6:3, 1:6:4, 1:6:5, 1:6:6, 1:6:7, 1:6:8, 1:6:9, 1:6:10, 1:6:11, 1:6:12, 1:6:13, 1:6:14, 1:6:15, 1:6:16, 1:6:17, 1:6:18, 1:6:19, 1:6:20, 1:7:1, 1:7:2, 1:7:3, 1:7:4, 1:7:5, 1:7:6, 1:7:7, 1:7:8, 1:7:9, 1:7:10, 1:7:11, 1:7:121:7:13, 1:7:14, 1:7:15, 1:7:16, 1:7:17, 1:7:18, 1:7:19, 1:7:20, 1:8:1, 1:8:2, 1:8:3, 1:8:4, 1:8:5, 1:8:6, 1:8:7, 1:8:9, 1:8:10, 1:8:11, 1:8:12, 1:8:13, 1:8:14, 1:8:15, 1:8:16, 1:8:17, 1:8:18, 1:8:19, 1:8:20, 1:9:1, 1:9:2, 1:9:3, 1:9:4, 1:9:5, 1:9:6, 1:9:7, 1:9:8, 1:9:9, 1:9:10 A mixture of any point value or any range of values ​​between any two points in the ranges 1:9:11, 1:9:12, 1:9:13, 1:9:14, 1:9:15, 1:9:16, 1:9:17, 1:9:18, 1:9:19, 1:9:20, 1:10:1, 1:10:2, 1:10:3, 1:10:4, 1:10:5, 1:10:6, 1:10:7, 1:10:8, 1:10:9, 1:10:10, 1:10:11, 1:10:12, 1:10:13, 1:10:14, 1:10:15, 1:10:16, 1:10:17, 1:10:18, 1:10:19, or 1:10:20.

[0031] Optionally, the resin is a mixture of hydrogenated nitrile rubber and hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer in a mass ratio of 1:(1-20). For example, the resin can be a mixture of hydrogenated nitrile rubber and hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer in any point value or range between any two points from a mass ratio of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, 1:19 or 1:20.

[0032] Optionally, the insulating filler is an electronic insulator, typically with a volume resistivity higher than 10 at room temperature. 9 The particle size is Ωcm and not greater than 60μm; furthermore, the insulating filler is any one or more of oxide insulating ceramics, insulating silicates, carbide insulators, or solid electrolyte powder. Optionally, the particle size can be 0.1μm-20μm.

[0033] Optionally, the oxide insulating ceramic is one or more of the following: alumina, fused / crystalline silica, magnesium oxide, zirconium oxide, zinc oxide, titanium oxide, perovskite-type composite oxide, and multi-metal oxide.

[0034] Optionally, the insulating silicate can be one or more of mica powder, talc powder, kaolin, wollastonite powder, bentonite, quartz powder, or sepiolite powder.

[0035] Optionally, the carbide insulator is one or more of boron nitride, aluminum nitride, or silicon nitride.

[0036] Optionally, the solid electrolyte powder is one or more of the following: sulfide solid electrolyte, oxide solid electrolyte, halide solid electrolyte, oxyhalide solid electrolyte, oxysulfide solid electrolyte, nitride solid electrolyte, sulfur oxide solid electrolyte, or borohydride solid electrolyte.

[0037] Optionally, the insulating filler is a mixture of alumina and quartz powder in a mass ratio of 10:(1-10). For example, the insulating filler can be a mixture of alumina and quartz powder in any point value or any range between any two points in a mass ratio of 10:1, 10:2, 10:3, 10:4, 10:5, 10:6, 10:7, 10:8, 10:9 or 10:10.

[0038] Optionally, the insulating filler is a mixture of magnesium oxide and boron nitride in a mass ratio of 1:(1-10). For example, the insulating filler can be a mixture of magnesium oxide and boron nitride in any point value or any range between two points in a mass ratio of 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10.

[0039] Optionally, the insulating filler is a mixture of sulfide electrolyte, oxide electrolyte, and oxyhalide electrolyte in a mass ratio of 10:(1-10):(1-10).

[0040] Optionally, the insulating filler can be any one or more of the following shapes: spherical, cubic, rod-shaped, linear, sheet-shaped, plate-shaped, or irregular.

[0041] A second aspect of the present invention provides a method for preparing a highly thixotropic adhesive liquid for a solid-state battery insulating frame, comprising the following steps: S1: Mix the low-polarity dispersant and resin in the specified proportions; S2: Add insulating filler to the material in step S1 and mix well to obtain a high thixotropic adhesive liquid for solid-state battery insulating frames.

[0042] A third aspect of this invention provides a solid-state battery comprising a highly thixotropic adhesive for an insulating frame, wherein the highly thixotropic adhesive is applied to the overhang region at the edge of the coating of the positive or negative electrode sheet of the solid-state battery. The application method includes any one of dispensing, 3D printing, screen printing, or spraying, and this invention is not limited thereto.

[0043] Compared with the prior art, the present invention achieves at least one of the following beneficial effects: (1) In the high thixotropic adhesive used in the insulating frame of solid-state batteries, the non-covalent interactions between the insulating filler, resin and low polarity dispersant components themselves and between the components construct a dynamically reversible physical cross-linking network of the slurry components, so that the static viscosity of the adhesive is higher than 5×10. 4 mPa•s, while the shear rate is not higher than 100 s -1 Under shear stress, the viscosity can be reduced to 10. 4 High thixotropy of slurry is achieved at a speed of less than mPa•s.

[0044] (2) The high thixotropic adhesive of the present invention is a high static viscosity slurry, which can prevent leakage and overflow of the slurry during the film formation process. At the same time, the high thixotropy can ensure that the viscosity of the slurry is greatly reduced under shearing action, ensuring the integrity of the coating pattern and achieving high precision and shape preservation of the coating pattern.

[0045] (3) The high thixotropic adhesive liquid of the present invention can be compatible with a wide range of solid content and component ratio, thereby adjusting the coating edge thickness and pressure shrinkage rate.

[0046] (4) The high thixotropic adhesive liquid of the present invention is compatible with a variety of coating methods, including dispensing, 3D printing, screen printing or spraying. Attached Figure Description

[0047] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of the rheological film formation of the slurry in the high thixotropic adhesive solution of Example 1 is shown; Figure 2 A photograph showing the border coating in Example 1 is shown; Figure 3 A schematic diagram showing the thickness values ​​of various parts of the frame in Embodiment 1 is shown; Figure 4 The rheological properties of the slurries from Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are shown in the comparison graph. Figure 5 The SEM topography of the border in Example 2 is shown; Figure 6 Comparative Example 2 shows a photograph with a coated border; Figure 7 A schematic diagram showing the thickness values ​​of various parts of the frame in Comparative Example 2 is provided. Figure 8 The changes in ionic conductivity of the sulfide electrolyte after contact with the solvents of Example 1, Example 3 and Comparative Example 3 are shown. Detailed Implementation

[0048] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0049] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0050] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art. The resins used in the following embodiments and comparative examples are all commercially available products. Hydrogenated styrene-butadiene rubber can also be prepared by referring to existing preparation methods, for example, patent CN201910814150.9; hydrogenated styrene-ethylene-butene-styrene block copolymer can refer to patent CN202310226522.2; hydrogenated styrene-isoprene-styrene block copolymer can refer to patent CN201610754184.X.

[0051] Example 1 In an exemplary embodiment of the present invention, the high thixotropic adhesive for the insulating frame of a solid-state battery, by mass fraction, comprises 9% insulating filler, 90% low-polarity dispersant, and 1% resin; wherein the insulating filler is spherical alumina particles with a particle size of 2 μm, the low-polarity dispersant is trimethylbenzene, and the resin is hydrogenated styrene-butadiene rubber with a molecular weight of 5.5 × 10⁻⁶. 5 g / mol.

[0052] The preparation method includes the following steps: S1: Mix the low-polarity dispersant and resin in proportion, and obtain the adhesive solution by double planetary stirring for 4 hours; S2: Add insulating filler to the adhesive solution and stir with a double planetary mixer for 4 hours to obtain a highly thixotropic adhesive solution.

[0053] Example 2 In an exemplary embodiment of the present invention, the high thixotropic adhesive for the insulating frame of a solid-state battery, by mass fraction, comprises 74% insulating filler, 25% low-polarity dispersant, and 1% resin; wherein the insulating filler is spherical alumina particles with particle sizes of 2 μm and 0.1 μm, taken in a mass ratio of 1:1; the low-polarity dispersant is butyl hexanoate; and the resin is a hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer with a molecular weight of 6 × 10⁻⁶. 5 g / mol.

[0054] The preparation method includes the following steps: S1: Mix the low-polarity dispersant and resin in proportion, and obtain the adhesive solution by double planetary stirring for 4 hours; S2: Add insulating filler to the adhesive solution and stir with a double planetary mixer for 4 hours to obtain a highly thixotropic adhesive solution.

[0055] Example 3 In an exemplary embodiment of the present invention, the high thixotropic adhesive for the insulating frame of a solid-state battery, by mass fraction, comprises 40% insulating filler, 50% low-polarity dispersant, and 10% resin; wherein the insulating filler is boehmite particles with a particle size of 10 μm, the low-polarity dispersant is hexyl hexanoate, and the resin is a hydrogenated styrene-ethylene-butene-styrene block copolymer with a molecular weight of 1.5 × 10⁻⁶. 6 g / mol.

[0056] The preparation method includes the following steps: S1: Mix the low-polarity dispersant and resin in proportion, and obtain the adhesive solution by double planetary stirring for 4 hours; S2: Add insulating filler to the adhesive solution and stir with a double planetary mixer for 4 hours to obtain a highly thixotropic adhesive solution.

[0057] Example 4 In an exemplary embodiment of the present invention, the high thixotropic adhesive for the insulating frame of a solid-state battery, by mass fraction, comprises 9% insulating filler, 90% low-polarity dispersant, and 1% resin; wherein the insulating filler is magnesium oxide with a particle size of 10 μm, the low-polarity dispersant is butyl octanoate, and the resin is hydrogenated styrene-isoprene-styrene block copolymer with a molecular weight of 7.5 × 10⁻⁶. 5 g / mol.

[0058] The preparation method includes the following steps: S1: Mix the low-polarity dispersant and resin in proportion, and obtain the adhesive solution by double planetary stirring for 4 hours; S2: Add insulating filler to the adhesive solution and stir with a double planetary mixer for 4 hours to obtain a highly thixotropic adhesive solution.

[0059] Example 5 In an exemplary embodiment of the present invention, the high thixotropic adhesive for the insulating frame of a solid-state battery, by mass fraction, comprises 74% insulating filler, 25% low-polarity dispersant, and 1% resin; wherein the insulating filler is spherical magnesium oxide particles with particle sizes of 10 μm and 0.2 μm, taken in a mass ratio of 1:1; the low-polarity dispersant is a mixture of dodecane and butyl hexanoate in a mass ratio of 1:10; and the resin is hydrogenated styrene-butadiene rubber with a molecular weight of 6 × 10⁻⁶. 5 g / mol.

[0060] The preparation method includes the following steps: S1: Mix the low-polarity dispersant and resin in proportion, and obtain the adhesive solution by double planetary stirring for 4 hours; S2: Add insulating filler to the adhesive solution and stir with a double planetary mixer for 4 hours to obtain a highly thixotropic adhesive solution.

[0061] Example 6 In an exemplary embodiment of the present invention, the high thixotropic adhesive for the insulating frame of a solid-state battery, by mass fraction, comprises 72% insulating filler, 25% low-polarity dispersant, and 3% resin; wherein the insulating filler is spherical magnesium oxide particles with particle sizes of 10 μm and 0.5 μm, taken in a mass ratio of 1:1; the low-polarity dispersant is a mixture of butyl octanoate and butyl hexanoate in a mass ratio of 1:1; and the resin is a mixture of hydrogenated styrene-butadiene rubber and hydrogenated styrene-ethylene-propylene-styrene block copolymer in a mass ratio of 1:4, and the molecular weight of all resins is 5.5 × 10⁻⁶. 5 g / mol.

[0062] The preparation method includes the following steps: S1: Mix the low-polarity dispersant and resin in proportion, and obtain the adhesive solution by double planetary stirring for 4 hours; S2: Add insulating filler to the adhesive solution and stir with a double planetary mixer for 4 hours to obtain a highly thixotropic adhesive solution.

[0063] Example 7 The main difference from Example 1 is that the resin is ethyl-modified hydrophobic chitosan.

[0064] Example 8 The main difference from Example 1 is that the resin is propyl-modified hydrophobic chitosan.

[0065] Example 9 The main difference from Example 1 is that the resin is silane-modified hydrophobic alginate.

[0066] Example 10 The main difference from Example 1 is that the resin is butyl-modified hydrophobic cellulose.

[0067] Example 11 The main difference from Example 1 is that the resin is ethyl-modified polyacrylic acid.

[0068] Example 12 The main difference from Example 1 is that the resin is a mixture of hydrogenated nitrile rubber, hydrogenated styrene-isoprene-styrene block copolymer, and hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer in a mass ratio of 1:10:10.

[0069] Example 13 The main difference from Example 1 is that the insulating filler is a mixture of spherical alumina and quartz powder in a mass ratio of 10:5.

[0070] Comparative Example 1 The main difference from Example 1 is that the resin is a low molecular weight hydrogenated nitrile butadiene rubber with a molecular weight of 1×10⁻⁶. 5 g / mol.

[0071] Comparative Example 2 The main difference from Example 7 is that the resin is unhydrophobically modified chitin.

[0072] Comparative Example 3 The main difference from Example 7 is that the resin is unhydrophobically modified chitosan.

[0073] Comparative Example 4 The main difference from Example 9 is that the resin is unhydrophobic modified alginate.

[0074] Comparative Example 5 The main difference from Example 5 is that the resin is unhydrogenated styrene-butadiene rubber.

[0075] Comparative Example 6 The main difference from Example 4 is that the resin is an unhydrogenated styrene-isoprene-styrene block copolymer.

[0076] Comparative Example 7 The main difference from Example 3 is that the resin is a non-hydrogenated styrene-ethylene-butene-styrene block copolymer.

[0077] Comparative Example 8 The main difference from Example 2 is that the resin is a non-hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer.

[0078] Comparative Example 9 In an exemplary comparative example of the present invention, the high thixotropic adhesive for the insulating frame of a solid-state battery, by mass fraction, comprises 5% insulating filler, 94% low-polarity dispersant, and 1% resin; wherein the insulating filler is spherical alumina particles with a particle size of 2 μm, the low-polarity dispersant is trimethylbenzene, and the resin is hydrogenated styrene-butadiene rubber with a molecular weight of 5.5 × 10⁻⁶. 5 g / mol.

[0079] The preparation method includes the following steps: S1: Mix the low-polarity dispersant and resin in proportion, and obtain the adhesive solution by double planetary stirring for 4 hours; S2: Add insulating filler to the adhesive solution and stir with a double planetary mixer for 4 hours to obtain a highly thixotropic adhesive solution.

[0080] Comparative Example 10 In an exemplary comparative example of the present invention, the high thixotropic adhesive for the insulating frame of a solid-state battery comprises, by mass fraction, 9% insulating filler, 90% dispersant, and 1% resin; wherein the insulating filler is spherical alumina particles with a particle size of 2 μm, the dispersant is toluene, and the resin is hydrogenated styrene-butadiene rubber with a molecular weight of 5.5 × 10⁻⁶. 5 g / mol.

[0081] The preparation method includes the following steps: S1: Mix the dispersant and resin in proportion, and obtain the adhesive solution by double planetary stirring for 4 hours; S2: Add insulating filler to the adhesive solution and stir with a double planetary mixer for 4 hours to obtain a highly thixotropic adhesive solution.

[0082] Test case The high thixotropic adhesives prepared in the above examples and comparative examples were subjected to performance tests, as shown in Table 1.

[0083] ① The test adhesive solution was tested at low shear (0.1 s). -1 The viscosity of the sample was tested according to the national standard GB / T 10247. ② Test the adhesive solution in 100s -1 Viscosity at shear rate was tested according to national standard GB / T 10247; ③ Rheological properties, tested in accordance with national standard GB / T 21059. ④ Standard deviation of coating edge thickness: Measure the thickness using a micrometer and calculate the standard deviation. ⑤ Compressive shrinkage rate: The initial thickness h1 of the coated frame is sealed with aluminum-plastic film, followed by 500 MPa isostatic pressure. After removing the sealed bag, the thickness h2 of the frame after compression is tested, and then the frame shrinkage rate Δ is calculated. .

[0084] Table 1

[0085] Referring to Table 1, the highly thixotropic adhesive prepared in this application exhibits good performance at low shear rates (0.1 s⁻¹). -1 The static viscosity at all values ​​is higher than 8.9 × 10⁻⁶. 4 mPa·s, up to a maximum of 6.1×10 5 Above mPa·s, it can effectively prevent leakage before coating and overflow after coating; at high shear rates (100 s⁻¹), it can effectively prevent leakage before coating and overflow after coating. -1 Under the action of ), the viscosity can be reduced to 4.9×10. 3The pressure is below mPa·s, ensuring good fluidity and pattern integrity of the slurry during the coating process. The coating borders of all embodiments are complete and defect-free, the standard deviation of thickness is controlled within 8.6 μm, and the compressive shrinkage rate is between 4.2% and 13.9%, indicating that the adhesive of this application has excellent high thixotropy, coating accuracy, and isostatic compressibility.

[0086] In Comparative Examples 1 and 9, the resin molecular weight was too low or the filler content was insufficient, resulting in insufficient static viscosity (<4.1×10⁻⁶). 4 The coating exhibited severe overflow during application (mPa·s); Comparative Examples 2-4 used unmodified resins containing polar groups (chitin, chitosan, alginate), which, although having sufficient static viscosity, lacked effective thixotropy, and the viscosity was low at 100s. -1 The viscosity remains above 1.5 × 10⁻⁶ after shearing. 4 The high concentration of mPa·s resulted in large-area defects during the coating process, with a thickness standard deviation exceeding 58 μm. Comparative Examples 5-8 used unhydrogenated unsaturated elastomers, which, while having acceptable rheological properties, exhibited poor chemical compatibility with sulfide electrolytes (introducing unsaturated bonds that react with the electrolyte), failing to meet the practical application requirements of solid-state batteries. Comparative Example 10 used the highly polar solvent toluene, which, although having sufficient static viscosity, had a high viscosity at 100 s⁻¹. -1 The viscosity after shearing is too high (>5.6×10). 3 The coating thickness was 68.1 μm, resulting in missing parts due to the high standard deviation of the coating thickness (mPa·s).

[0087] Figure 1 This diagram illustrates the rheological film formation of the slurry in the high thixotropic adhesive solution of Example 1. Figure 4 The diagram shows a comparison of the rheological properties of the slurries from Example 2, Comparative Example 1, Comparative Example 2, and Comparative Example 3. (Reference) Figure 1 and Figure 4 As shown, the high thixotropic adhesive prepared in this application possesses both good thixotropic and rheological properties, and exhibits strong chemical compatibility with sulfide electrolytes. Comparative Example 1 has insufficient initial viscosity, Comparative Example 2 has insufficient thixotropy, and Comparative Example 3 has sufficient rheological properties but reacts with the electrolyte and has poor compatibility.

[0088] Figure 2 A photograph showing the border coating in Example 1 is shown. Figure 3 A schematic diagram showing the thickness values ​​of various parts of the frame in Embodiment 1 is shown. Figure 5 The SEM topography of the border in Example 2 is shown, with reference to... Figure 2 , Figure 3 , Figure 5 As shown, the coating of this application has a complete and defect-free border, and the coating thickness is uniform. Figure 6 Comparative Example 2 shows a photograph with a coated border. Figure 7 This diagram illustrates the thickness values ​​of various parts of the frame in Comparative Example 2. Figure 6 and Figure 7 As shown in the figure, it can be seen that the insufficient thixotropy of Comparative Example 2 resulted in large-area missing printing and poor coating thickness uniformity during the coating process.

[0089] Figure 8 The changes in ionic conductivity of the sulfide electrolyte after contact with the solvents of Example 1, Example 3, and Comparative Example 3 are shown. It can be seen that Comparative Example 3 reacts with the electrolyte, exhibiting poor compatibility.

[0090] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A highly thixotropic adhesive liquid for use in insulating frames of solid-state batteries, characterized in that, By mass fraction, the high thixotropic adhesive for solid-state battery insulating frames comprises 9%~95% insulating filler, 3%~90% low polarity dispersant and 1%~40% resin; The resin is a nonpolar, low-polar, or amphiphilic polymer that is soluble in the low-polarity dispersant.

2. The high thixotropic adhesive liquid for solid-state battery insulating frames according to claim 1, characterized in that, High thixotropic adhesive liquid with a viscosity greater than 5×10 4 mPa•s, while the shear rate is not higher than 100 s -1 Under shear stress, the viscosity can be reduced to 10. 4 mPa·s or less.

3. The high thixotropic adhesive liquid for solid-state battery insulating frames according to claim 1, characterized in that, The low-polarity dispersant has a flash point >60℃, a boiling point >60℃, and a dielectric constant <5.5; furthermore, the low-polarity dispersant is any one or more of thiol, diphenyl ether, butyl benzoate, dodecane, tetradecane, hexadecane, butyl hexanoate, hexyl hexanoate, butyl octanoate, diethyl adipate, or dipropylene glycol methyl ether.

4. The high thixotropic adhesive liquid for solid-state battery insulating frames according to claim 1, characterized in that, The resin is an amphiphilic polymer containing hydrogen bond donors or acceptors and soluble in a low-polarity dispersant, or has a weight-average molecular weight of not less than 5 × 10⁻⁶. 5 Any one or more of the following high molecular weight linear elastomers with a g / mol ratio.

5. The high thixotropic adhesive liquid for solid-state battery insulating frames according to claim 4, characterized in that, The amphiphilic polymer is any one or more of hydrophobic modified cellulose, hydrophobic modified chitin, hydrophobic modified chitosan, or hydrophobic modified alginate. The structural formula of hydrophobically modified cellulose is as follows: ； The structural formula of hydrophobically modified chitin is as follows: ； The structural formula of hydrophobically modified chitosan is as follows: ； The structural formula of hydrophobically modified alginate is as follows: ； In the amphiphilic polymer, R is independently selected from any one or more of -W, -O=CX, -Si-Y, and -NH-Z, W, X, Y, and Z are any one of alkyl or halogen groups, and n is an integer not less than 10. The polymer containing hydrogen bond donors or acceptors and soluble in the dispersant is any one or more of modified polyacrylic acid, modified polyurethane, modified polyvinylidene fluoride, or block polymers containing repeating units of both modified polyacrylic acid and modified polyurethane. The modified polyacrylic acid structure is as follows: ; The structural formula of modified polyurethane is :; The structural formula of modified polyvinylidene fluoride is: or ; In the polymer containing hydrogen bond donors or acceptors and dissolved in the dispersant, R is independently selected from any one or more of -V, -OW, -O=CX, -Si-Y, and -NH-Z, where V, W, X, Y, and Z are alkyl or halogen groups; and n is an integer not less than 10. The high molecular weight linear elastomer is any one or more of hydrogenated styrene-butadiene rubber, hydrogenated nitrile rubber, polyolefin elastomer, hydrogenated styrene-isoprene-styrene block copolymer, hydrogenated styrene-ethylene-butene-styrene block copolymer, and hydrogenated styrene-ethylene-ethylene-propylene-styrene block copolymer.

6. The high thixotropic adhesive liquid for solid-state battery insulating frames according to claim 1, characterized in that, The insulating filler is an electronic insulator, and its volume resistivity at room temperature is typically higher than 10. 9 Ωcm, with a particle size not exceeding 60μm; furthermore, the insulating filler is any one or more of oxide insulating ceramics, insulating silicates, carbide insulators, or solid electrolyte powders.

7. The high thixotropic adhesive liquid for solid-state battery insulating frames according to claim 6, characterized in that, Oxide insulating ceramics are one or more of the following: alumina, fused / crystalline silicon dioxide, magnesium oxide, zirconium oxide, zinc oxide, titanium oxide, perovskite-type composite oxides, and multi-metal oxides; Insulating silicates are one or more of the following: mica powder, talc powder, kaolin, wollastonite powder, bentonite, quartz powder, or sepiolite powder; The carbide insulator is one or more of boron nitride, aluminum nitride, or silicon nitride; The solid electrolyte powder is one or more of the following: sulfide solid electrolyte, oxide solid electrolyte, halide solid electrolyte, oxyhalide solid electrolyte, oxysulfide solid electrolyte, nitride solid electrolyte, sulfur oxide solid electrolyte, or borohydride solid electrolyte.

8. A method for preparing a highly thixotropic adhesive liquid for a solid-state battery insulating frame as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Mix the low-polarity dispersant and resin in the specified proportions; S2: Add insulating filler to the material in step S1 and mix well to obtain a high thixotropic adhesive liquid for solid-state battery insulating frames.

9. A solid-state battery, characterized in that, The solid-state battery includes the high thixotropic adhesive liquid for insulating frames of solid-state batteries as described in any one of claims 1-7, and the high thixotropic adhesive liquid is applied to the overhang area at the edge of the coating of the positive or negative electrode sheet of the solid-state battery.

Images