High-temperature-resistant aluminum-plastic film, preparation method thereof and solid-state battery

Abstract

The application belongs to the technical field of lithium battery packaging materials, and particularly relates to a high-temperature-resistant aluminum-plastic film, a preparation method thereof and a solid-state battery, which sequentially comprise, from top to bottom, a PEN layer, an outer adhesive layer, a high-temperature-resistant heat-insulating protective layer, a first adhesive layer, an aluminum foil layer, a second adhesive layer, a nano-particle reinforced PPS bonding layer and an elastomer modified PPS heat-sealing layer; the nano-particle reinforced PPS bonding layer comprises the following components in parts by mass: 70-90 parts of PPS resin, 5-15 parts of nano-silicon dioxide or nano-aluminum oxide and 3-10 parts of maleic anhydride grafted styrene-ethylene-butylene-styrene block copolymer; and the elastomer modified PPS heat-sealing layer comprises the following components in parts by mass: 80-95 parts of PPS resin, 5-20 parts of hydrogenated styrene-ethylene-butylene-styrene block copolymer or a maleic anhydride grafting product thereof.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery packaging material technology, specifically relating to a high-temperature resistant aluminum-plastic film and its preparation method, and a solid-state battery. Background Technology

[0002] Aluminum-plastic composite film is the core encapsulation material for soft-pack lithium-ion batteries. Its traditional structure is typically: outer nylon (PA) / adhesive / intermediate aluminum foil (Al) / adhesive / inner cast polypropylene (CPP). However, traditional material systems have inherent temperature limits: the glass transition temperature (Tg) of the PA layer is approximately 120 °C, and the long-term operating temperature is below 150 °C; the melting point of the CPP layer is typically between 160-170 °C.

[0003] As battery technology advances towards higher energy density and solid-state technology, unprecedented demands are being placed on the high-temperature resistance of encapsulation materials. Solid-state batteries, in particular, based on sulfide or oxide electrolytes, typically operate within the 80-150°C range. During fast charging, overload, or localized thermal runaway, internal temperatures can briefly surge to 200°C or even higher. Under these extreme high-temperature conditions, traditional aluminum-plastic films can completely lose their encapsulation function due to melting of the inner CPP layer, softening of the outer PA layer, and failure of interlayer adhesives, leading to battery failure and even safety incidents.

[0004] PPS (polyphenylene sulfide) material has a melting point as high as 280℃, but as a crystalline polymer, it has low surface energy, strong chemical inertness, and lacks active groups, resulting in poor bonding performance with adhesives. More importantly, PPS material is brittle, and its flexibility and impact resistance cannot meet the frequent bending requirements of aluminum-plastic film in battery encapsulation and use. Therefore, the industry has not conducted in-depth research on the use of PPS material as aluminum-plastic film for a long time. However, with the development of ultra-high temperature sealing technology, there is an urgent need for an aluminum-plastic film solution that is completely innovative in terms of material system and structural design to solve the ultra-high temperature encapsulation problem faced by solid-state batteries.

[0005] Therefore, how to simultaneously overcome the shortcomings of insufficient interlayer adhesion and bending resistance of PPS materials in aluminum-plastic films is a technical problem that urgently needs to be solved in this field.

[0006] It should be noted that the information disclosed in this background section is only for understanding the background technology of the present application concept, and therefore, the above description is not considered to constitute prior art information. Summary of the Invention

[0007] This disclosure provides at least one high-temperature resistant aluminum-plastic film and its preparation method, as well as a solid-state battery.

[0008] In a first aspect, embodiments of this disclosure provide a high-temperature resistant aluminum-plastic film, comprising, from top to bottom: a PEN layer, an outer adhesive layer, a high-temperature resistant heat insulation protective layer, a first adhesive layer, an aluminum foil layer, a second adhesive layer, a nanoparticle-reinforced PPS adhesive layer, and an elastomer-modified PPS heat-sealing layer; wherein, the nanoparticle-reinforced PPS adhesive layer comprises, by weight, the following components: 70-90 parts of PPS resin, 5-15 parts of nano-silica or nano-alumina, and 3-10 parts of maleic anhydride-grafted styrene-ethylene-butene-styrene block copolymer; the elastomer-modified PPS heat-sealing layer comprises, by weight, the following components: 80-95 parts of PPS resin, and 5-20 parts of hydrogenated styrene-ethylene-butene-styrene block copolymer or its maleic anhydride graft.

[0009] In one optional embodiment, the high-temperature resistant heat insulation protective layer is composed of a high-performance polymer film with an operating temperature of not less than 200°C; the high-performance polymer includes one or more of polyimide, polyether ether ketone, and polyamide imide.

[0010] In one optional embodiment, the raw material of the outer adhesive layer includes one or more of high-temperature modified polyurethane adhesive, high-temperature epoxy adhesive, and silane modified polyether adhesive, with a dry adhesive thickness of 1-5 μm; the raw material of the first adhesive layer includes one or more of high-temperature modified polyurethane adhesive, high-temperature epoxy adhesive, and silane modified polyether adhesive, with a dry adhesive thickness of 2-5 μm; the raw material of the second adhesive layer includes one or more of high-temperature epoxy adhesive, phenolic resin adhesive, polyimide adhesive, cyanate ester resin adhesive, or the above adhesives as modified adhesives, with a dry adhesive thickness of 2-5 μm; wherein, the drying and curing temperature and the lamination temperature of the second adhesive layer are both not lower than 160°C.

[0011] In one optional embodiment, the thickness of the PEN layer is 12–25 μm; the thickness of the high-temperature resistant heat insulation protective layer is 5–15 μm; the aluminum foil layer includes aluminum foil and a surface protective film formed after passivation treatment, wherein the thickness of the aluminum foil is 30–50 μm and the thickness of the surface protective film is 50–500 nm.

[0012] In one optional embodiment, the thickness of the nanoparticle-reinforced PPS adhesive layer is 8–15 μm; and the thickness of the elastomer-modified PPS heat-sealing layer is 25–35 μm.

[0013] Secondly, this disclosure also provides a method for preparing a high-temperature resistant aluminum-plastic film as described above, comprising the following steps: S1, coating an adhesive on the surface of a PEN layer to form an outer adhesive layer, then laminating it with a high-temperature resistant heat-insulating protective layer, and dry-laminating it to obtain an outer composite substrate; S2, coating an adhesive on the surface of the high-temperature resistant heat-insulating protective layer of the outer composite substrate to form a first adhesive layer, preheating and drying it, and then laminating it with the matte surface of an aluminum foil layer, and dry-laminating it to obtain an intermediate composite structure; S3, using a double-layer co-extrusion casting process to extrude the raw materials of a nanoparticle-reinforced PPS adhesive layer and an elastomer-modified PPS heat-sealing layer respectively to obtain a PPS inner substrate; S4, coating an adhesive on the glossy surface of the aluminum foil layer of the intermediate composite structure, preheating and drying it, and then laminating it with one side of the nanoparticle-reinforced PPS adhesive layer of the PPS inner substrate, and dry-laminating it to obtain a composite film; S5, curing the composite film to obtain an aluminum-plastic film.

[0014] In one optional embodiment, the dry lamination in S1 is carried out at 80–120°C and 0.4–0.6 MPa; the preheating and drying in S2 is carried out at 80–100°C and 0.5–0.7 MPa; the preheating and drying in S4 is carried out at 90–110°C and 170–190°C and 0.7–0.9 MPa.

[0015] In an optional embodiment, the double-layer co-extrusion casting process in S3 includes: melting and plasticizing the raw materials of the nanoparticle-reinforced PPS adhesive layer and the elastomer-modified PPS heat-sealing layer through two extruders respectively, with the temperature of each section of the extruder being 300-320°C, extruding the molten sheet through a double-layer co-extrusion die, with the die temperature being 310-330°C, and cooling and shaping it on a cooling roller to obtain the PPS inner layer substrate.

[0016] In one optional embodiment, the curing process in S4 includes curing in a curing chamber at 40–60°C for 3–7 days.

[0017] Thirdly, embodiments of this disclosure also provide a solid-state battery, including the aluminum-plastic film as described above.

[0018] The beneficial effects of this invention are that the high-temperature resistant aluminum-plastic film and its preparation method, as well as the solid-state battery, utilize a composite design of a high-temperature resistant heat insulation layer and a double-layer PPS inner layer. The nanoparticle-reinforced PPS adhesive layer uses nanoparticles to improve the anchoring effect with the adhesive, and combines with elastomer copolymers to eliminate the brittleness caused by rigid nanoparticles. The elastomer-modified PPS heat-sealing layer uses elastomer copolymers to improve flexibility and increases the PPS content to enhance the heat-sealing performance of the layer. The combination of the double-layer PPS inner layer overcomes the defects in adhesion and bending resistance, and further improves the heat-sealing performance of the material during modification, realizing the application of PPS material in ultra-high temperature heat-sealing aluminum-plastic film.

[0019] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained through the structures particularly pointed out in the description and the drawings.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of a high-temperature resistant aluminum-plastic film provided in an embodiment of this disclosure.

[0023] In the picture: 1. PEN layer; 2. Outer adhesive layer; 3. High-temperature resistant heat insulation protective layer; 4. First adhesive layer; 5. Aluminum foil layer; 6. Second adhesive layer; 7. Nanoparticle-reinforced PPS adhesive layer; 8. Elastomer-modified PPS heat-sealing layer. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] As used herein, the phrases “in one embodiment,” “according to one embodiment,” “in some embodiments,” etc., generally refer to the fact that a particular feature, structure, or characteristic following the phrase can be included in at least one embodiment of this disclosure. Therefore, a particular feature, structure, or characteristic can be included in more than one embodiment of this disclosure, such that these phrases do not necessarily refer to the same embodiment. As used herein, the terms “example,” “exemplary,” etc., are used to “serve as an example, instance, or illustration.” Any implementation, aspect, or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or superior to other implementations, aspects, or designs. Rather, the use of the terms “example,” “exemplary,” etc., is intended to present concepts in a specific manner.

[0026] In this document, exemplary embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings. As used herein, expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0027] The terminology used herein is for the purpose of describing specific exemplary configurations only and is not intended to be limiting. As used herein, the singular articles “a,” “an,” and “the” may also be intended to include plural forms unless otherwise clearly stated herein. The terms “comprising,” “including,” and “having” are inclusive and thus specify the presence of features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein should not be construed as requiring them to be performed in the specific order discussed or shown, unless specifically identified as such. Additional or alternative steps may be employed.

[0028] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0029] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] This disclosure provides an aluminum-plastic film, comprising, from top to bottom: a PEN layer 1, an outer adhesive layer 2, a high-temperature resistant heat-insulating protective layer 3, a first adhesive layer 4, an aluminum foil layer 5, a second adhesive layer 6, a nanoparticle-reinforced PPS adhesive layer 7, and an elastomer-modified PPS heat-sealing layer 8; wherein, the nanoparticle-reinforced PPS adhesive layer 7 comprises, by weight, the following components: 70-90 parts of PPS resin, 5-15 parts of nano-silica or nano-alumina, and 3-10 parts of maleic anhydride-grafted styrene-ethylene-butene-styrene block copolymer; the elastomer-modified PPS heat-sealing layer 8 comprises, by weight, the following components: 80-95 parts of PPS resin, and 5-20 parts of hydrogenated styrene-ethylene-butene-styrene block copolymer or its maleic anhydride graft.

[0031] In the following text, layer 7 refers to nanoparticle-reinforced PPS adhesive layer 7, layer 8 refers to elastomer-modified PPS heat-sealing layer 8, and the descriptions of the other layers are the same.

[0032] Specifically, the addition of nanoparticles to the nanoparticle-reinforced PPS adhesive layer 7 enhances rigidity and bonding strength with the adhesive, while the compatibilizer improves the compatibility between PPS and the elastomer; the addition of elastomers to the elastomer-modified PPS heat-sealing layer 8 significantly improves the brittleness of PPS, endowing it with the necessary flexibility and heat-sealing performance, enabling it to achieve reliable heat sealing at temperatures above 200 °C.

[0033] In some embodiments, specifically, the high-temperature resistant heat insulation protective layer 3 is composed of a high-performance polymer film with an operating temperature of not less than 200°C; the high-performance polymer includes one or more of polyimide, polyether ether ketone, and polyamide imide.

[0034] In some embodiments, specifically, the raw material of the outer adhesive layer 2 includes one or more of high-temperature modified polyurethane adhesive, high-temperature epoxy adhesive, and silane modified polyether adhesive, with a dry adhesive thickness of 1-5 μm; the raw material of the first adhesive layer 4 includes one or more of high-temperature modified polyurethane adhesive, high-temperature epoxy adhesive, and silane modified polyether adhesive, with a dry adhesive thickness of 2-5 μm; the raw material of the second adhesive layer 6 includes one or more of high-temperature epoxy adhesive, phenolic resin adhesive, polyimide adhesive, cyanate ester resin adhesive, or the above adhesives as modified adhesives, with a dry adhesive thickness of 2-5 μm; wherein, the drying and curing temperature and the lamination temperature of the second adhesive layer 6 are both not lower than 160°C, preferably 170-220°C. The second adhesive layer 6 is crucial for ensuring a reliable bond between the aluminum foil and the PPS inner layer. Since this interface directly faces the high internal temperature, it requires extremely high temperature resistance of the adhesive. High-temperature curing forms a stable network structure with high cross-linking density to ensure the stability of its performance in subsequent use environments.

[0035] In some embodiments, specifically, the thickness of the PEN layer 1 is 12–25 μm, which, as the outermost layer, mainly provides mechanical protection, scratch resistance, and primary barrier properties; the thickness of the high-temperature resistant heat insulation protective layer 3 is 5–15 μm, and its function is to act as an active thermal management barrier, effectively blocking and dissipating heat conducted from the battery interior through the aluminum foil, ensuring that the outer PEN layer 1 is always within its safe operating temperature range; the aluminum foil layer 5 includes aluminum foil and a surface protective film formed after passivation treatment, wherein the thickness of the aluminum foil is 30–50 μm. The aluminum foil layer 5 is the core of water and oxygen barrier, and to further improve its corrosion resistance, its surface needs to be treated, preferably anodizing or environmentally friendly chromate / ceramic passivation treatment to form a surface protective film, and the thickness of the treated surface protective film is 50–500 nm.

[0036] In some embodiments, specifically, the thickness of the nanoparticle-reinforced PPS adhesive layer 7 is 8–15 μm; and the thickness of the elastomer-modified PPS heat-sealing layer 8 is 25–35 μm.

[0037] This disclosure also provides a method for preparing a high-temperature resistant aluminum-plastic film as described above, comprising the following steps: S1, coating an adhesive on the surface of a PEN layer 1 to form an outer adhesive layer 2, and then laminating it with a high-temperature resistant heat insulation protective layer 3 to obtain an outer composite substrate by dry lamination; S2, coating an adhesive on the surface of the high-temperature resistant heat insulation protective layer 3 of the outer composite substrate to form a first adhesive layer 4, preheating and drying it, and then laminating it with the matte surface of an aluminum foil layer 5 to obtain an intermediate composite structure by dry lamination; S3, using a double-layer co-extrusion casting process to extrude the raw materials of a nanoparticle-reinforced PPS adhesive layer 7 and an elastomer-modified PPS heat-sealing layer 8 to obtain a PPS inner substrate; S4, coating an adhesive on the glossy surface of the aluminum foil layer 5 of the intermediate composite structure, preheating and drying it for curing, and then laminating it with one side of the nanoparticle-reinforced PPS adhesive layer 7 of the PPS inner substrate by dry lamination to obtain a composite film; S5, subjecting the composite film to a curing treatment to obtain a high-temperature resistant aluminum-plastic film.

[0038] In some embodiments, specifically, the dry lamination conditions in S1 include 80–120°C and 0.4–0.6 MPa; the preheating and drying temperature in S2 is 80–100°C, and the dry lamination conditions include 80–100°C and 0.5–0.7 MPa; the preheating and drying temperature in S4 is 90–110°C, and the dry lamination conditions include 170–190°C and 0.7–0.9 MPa.

[0039] In some embodiments, specifically, the double-layer co-extrusion casting process in S3 includes: melting and plasticizing the raw materials of nanoparticle-reinforced PPS adhesive layer 7 and elastomer-modified PPS heat-sealing layer 8 through two extruders respectively, with the temperature of each section of the extruder being 300-320°C, extruding molten sheets through a double-layer co-extrusion die, with the die temperature being 310-330°C, and cooling and shaping on a cooling roller to obtain the PPS inner layer substrate.

[0040] In some embodiments, specifically, the curing process in S4 includes curing in a curing room at 40–60°C for 3–7 days.

[0041] This disclosure also provides a solid-state battery, including the aluminum-plastic film as described above.

[0042] The performance of the aluminum-plastic film provided by this invention was tested according to the following method: (1) Heat seal strength: The heat seal strength of a 15mm wide strip is tested by a heat sealer at 230℃ and 0.3MPa pressure for 3 seconds. After cooling, the heat seal strength of the strip is tested by a universal testing machine according to GB / T 23512-2009 standard. The unit is N / 15mm.

[0043] (2) Peel strength: The peel strength between the aluminum foil layer and the inner layer was tested using a universal testing machine according to GB / T 2792-2014 standard, with the unit being N / 15mm. The strength was tested at room temperature and after aging at 200℃ for 500 hours.

[0044] (3) Electrolyte corrosion resistance: Immerse the sample in a simulated solid electrolyte at 85°C for 7 days. After taking it out, observe whether there are any corrosion phenomena such as pitting or blackening on the surface of the aluminum foil.

[0045] (4) High temperature durability: The sample was placed in a constant temperature oven at 200℃ for 1000 hours. After taking it out, the appearance changes of each layer were observed and the decay rate of key performance was tested.

[0046] (5) Insulation resistance: The insulation resistance of the aluminum-plastic film was measured using an insulation resistance tester at a test voltage of 500V DC, in MΩ. The initial test value and the value after aging at 200℃ for 500 hours were recorded.

[0047] Example 1, the preparation method of high temperature resistant aluminum-plastic film includes: Outer layer lamination: 16μm PEN and 10μm PI film are laminated at 100℃ and 0.5MPa using a high-temperature resistant silicone-based adhesive.

[0048] Intermediate lamination: A high-temperature resistant polyurethane adhesive is coated on the PI surface and laminated with a 45μm aluminum foil matte surface at 90℃.

[0049] Inner layer preparation: A double-layer co-extrusion casting process was used to simultaneously extrude: a nanoparticle-reinforced PPS adhesive layer: 85 parts PPS, 10 parts nano Al2O3, and 5 parts SEBS-g-MAH; and an elastomer-modified PPS heat-sealing layer: 90 parts PPS and 10 parts hydrogenated SEBS. The total thickness was controlled at 40 μm (approximately 12 μm for layer 7 and approximately 28 μm for layer 8).

[0050] Final lamination: A high-temperature resistant epoxy adhesive is coated on the glossy surface of the aluminum foil, dried at 100°C, and then laminated with one side of the PPS adhesive layer at 180°C and 0.8MPa.

[0051] Curing: Place the composite film in a curing room at 50°C for 7 days to allow each adhesive layer to fully cure.

[0052] Example 2, the preparation method of high temperature resistant aluminum-plastic film includes: Outer layer lamination: A 20μm PEN film and a 5μm PI film are laminated together using a high-temperature resistant silicone-based adhesive at 100℃ and 0.4MPa.

[0053] Intermediate lamination: A high-temperature resistant polyurethane adhesive is coated on the PI surface and laminated with a 35μm aluminum foil matte surface at 90℃.

[0054] Inner layer preparation: A double-layer co-extrusion casting process was used to simultaneously extrude: a nanoparticle-reinforced PPS adhesive layer: 85 parts PPS, 10 parts nano Al2O3, and 5 parts SEBS-g-MAH; and an elastomer-modified PPS heat-sealing layer: 90 parts PPS and 10 parts hydrogenated SEBS. The total thickness was controlled at 35 μm (approximately 10 μm for layer 7 and approximately 25 μm for layer 8).

[0055] Final lamination: A high-temperature resistant epoxy adhesive is coated on the glossy surface of the aluminum foil, dried at 100°C, and then laminated with one side of the PPS adhesive layer at 180°C and 0.8MPa.

[0056] Curing: Place the composite film in a curing room at 40-50℃ for 7 days to allow each adhesive layer to fully cure.

[0057] Example 3, the preparation method of high temperature resistant aluminum-plastic film includes: Outer layer lamination: 25μm PEN and 15μm PI film are laminated at 100℃ and 0.6MPa using a high-temperature resistant silicone-based adhesive.

[0058] Intermediate lamination: A high-temperature resistant polyurethane adhesive is coated on the PI surface and laminated with a 55μm aluminum foil matte surface at 90℃.

[0059] Inner layer preparation: A double-layer co-extrusion casting process was used, simultaneously extruding: a nanoparticle-reinforced PPS adhesive layer: 85 parts PPS, 10 parts nano Al2O3, and 5 parts SEBS-g-MAH; and an elastomer-modified PPS heat-sealing layer: 90 parts PPS and 10 parts hydrogenated SEBS. The total thickness was controlled at 40 μm (approximately 15 μm for layer 7 and approximately 35 μm for layer 8).

[0060] Final lamination: A high-temperature resistant epoxy adhesive is coated on the glossy surface of the aluminum foil, dried at 100°C, and then laminated with one side of the PPS adhesive layer at 180°C and 0.8MPa.

[0061] Curing: Place the composite film in a curing room at 40-50℃ for 7 days to allow each adhesive layer to fully cure.

[0062] Comparative Example 1, the preparation method of high-temperature resistant aluminum-plastic film includes: Commercially available standard aluminum-plastic film (outer layer 25μm PA / adhesive / middle layer 40μm Al / adhesive / inner layer 40μm CPP).

[0063] Comparative Example 2, the preparation method of high-temperature resistant aluminum-plastic film includes: A comparative example, whose structure is similar to that of Embodiment 1 of the present invention, but omitting the PI thermal insulation protective layer 3 and the outer adhesive layer 2, has the following structure: PEN layer / first adhesive layer / aluminum foil layer / second adhesive layer / PPS inner layer. This is used to demonstrate the key thermal insulation function of the PI layer.

[0064] Outer layer lamination: A high-temperature resistant polyurethane adhesive is coated on the PEN surface and laminated with a 45μm aluminum foil matte surface at 90℃.

[0065] Inner layer preparation: The PPS inner layer was prepared using a double-layer co-extrusion casting process, with the same process parameters as in Example 1.

[0066] Final lamination: A high-temperature resistant epoxy adhesive is coated on the glossy surface of the aluminum foil, dried at 100°C, and then laminated with one side of the PPS adhesive layer at 180°C and 0.8MPa.

[0067] Curing: Place the composite film in a curing room at 50°C for 7 days to allow each adhesive layer to fully cure.

[0068] Comparative Example 3, the preparation method of high-temperature resistant aluminum-plastic film includes: A comparative example, in which the inner layer of PPS is a single layer, uses a mixture of layers 7 and 8 from Example 1 (82.5 parts PPS, 5 parts nano-alumina, 2.5 parts SEBS-g-MAH, and 10 parts hydrogenated SEBS). This is used to demonstrate the functional advantages of the two-layer PPS structure.

[0069] Inner layer preparation: PPS inner layer is prepared by single-layer co-extrusion casting process, with extruder temperature of 300-320℃, die temperature of 310-330℃, and thickness of 40μm; The remaining steps are the same as in Example 1.

[0070] Performance test results The aluminum-plastic films obtained in Examples 1-3 of the present invention were tested with those in Comparative Examples 1-3, and the results are shown in the table below.

[0071] Table 1: Summary Table of Test Results for High Temperature Resistant Aluminum-Plastic Film

[0072] Test results show that the high-temperature resistant aluminum-plastic film prepared by this invention exhibits significantly better performance (heat sealing, interlayer adhesion, barrier properties, corrosion resistance, and insulation) than traditional commercial aluminum-plastic films under extreme high-temperature conditions, fully meeting the stringent encapsulation requirements of high-temperature solid-state batteries. The built-in PI heat insulation layer effectively protects the PEN layer, ensuring its integrity even after high-temperature testing; the second adhesive layer and the double-layer PPS inner layer design demonstrate extremely high interfacial stability and reliability.

[0073] In summary, this high-temperature resistant aluminum-plastic film and its preparation method, along with the solid-state battery, utilize a composite design of a high-temperature resistant heat insulation layer and a double-layer PPS inner layer. The nanoparticle-reinforced PPS adhesive layer uses nanoparticles to improve the anchoring effect with the adhesive, and combines them with an elastomer copolymer to eliminate the brittleness caused by rigid nanoparticles. The elastomer-modified PPS heat-sealing layer uses an elastomer copolymer to improve flexibility and increases the PPS content to enhance the heat-sealing performance of this layer. The combination of the double-layer PPS inner layer overcomes both adhesion and bending resistance defects, and further improves the heat-sealing performance of the material during modification, thus realizing the application of PPS material in ultra-high temperature heat-sealing aluminum-plastic films.

[0074] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An aluminum-plastic film, characterized in that, From top to bottom, they include: PEN layer (1), outer adhesive layer (2), high temperature heat insulation protective layer (3), first adhesive layer (4), aluminum foil layer (5), second adhesive layer (6), nanoparticle reinforced PPS adhesive layer (7), elastomer modified PPS heat seal layer (8). The nanoparticle-reinforced PPS adhesive layer (7) comprises the following components by mass: 70-90 parts of PPS resin, 5-15 parts of nano silica or nano alumina, and 3-10 parts of maleic anhydride-grafted styrene-ethylene-butene-styrene block copolymer. The elastomer-modified PPS heat-sealing layer (8) comprises the following components by mass: 80-95 parts of PPS resin, and 5-20 parts of hydrogenated styrene-ethylene-butene-styrene block copolymer or its maleic anhydride graft.

2. The aluminum-plastic film as described in claim 1, characterized in that, The high-temperature resistant heat insulation protective layer (3) is composed of a high-performance polymer film with a working temperature of not less than 200℃; The high-performance polymer includes one or more of polyimide, polyether ether ketone, and polyamide imide.

3. The aluminum-plastic film as described in claim 1, characterized in that, The raw materials of the outer adhesive layer (2) include one or more of high-temperature modified polyurethane adhesive, high-temperature epoxy adhesive, and silane modified polyether adhesive, and the dry adhesive thickness is 1 to 5 μm. The raw materials of the first adhesive layer (4) include one or more of high-temperature modified polyurethane adhesive, high-temperature epoxy adhesive, and silane modified polyether adhesive, and the dry adhesive thickness is 2 to 5 μm; The raw materials of the second adhesive layer (6) include high-temperature resistant epoxy adhesive, phenolic resin adhesive, polyimide adhesive, cyanate ester resin adhesive, or one or more of the above adhesives as modified adhesives, and the dry adhesive thickness is 2 to 5 μm. The drying and curing temperature and the composite temperature of the second adhesive layer (6) are both not lower than 160°C.

4. The aluminum-plastic film as described in claim 1, characterized in that, The thickness of the PEN layer (1) is 12-25 μm; The thickness of the high-temperature resistant heat insulation protective layer (3) is 5-15 μm; The aluminum foil layer (5) includes an aluminum foil and a surface protective film formed after passivation treatment, wherein the thickness of the aluminum foil is 30-50 μm and the thickness of the surface protective film is 50-500 nm.

5. The aluminum-plastic film as described in claim 1, characterized in that, The thickness of the nanoparticle-reinforced PPS adhesive layer (7) is 8–15 μm; The thickness of the elastomer-modified PPS heat-sealing layer (8) is 25-35 μm.

6. A method for preparing an aluminum-plastic film as described in any one of claims 1-5, characterized in that, Includes the following steps: S1, an adhesive is applied to the surface of the PEN layer (1) to form an outer adhesive layer (2), which is then laminated with a high-temperature heat-insulating protective layer (3) to obtain an outer composite substrate by dry lamination; S2, an adhesive is applied to the surface of the high temperature insulation protective layer (3) of the outer composite substrate to form the first adhesive layer (4), which is then preheated and dried and then laminated with the matte surface of the aluminum foil layer (5) to obtain the intermediate composite structure through dry lamination. S3, the raw materials of nanoparticle-reinforced PPS adhesive layer (7) and elastomer-modified PPS heat-sealing layer (8) are extruded separately using a double-layer co-extrusion casting process to obtain PPS inner layer substrate; S4, apply adhesive to the bright side of the aluminum foil layer (5) of the intermediate composite structure, preheat and dry to cure, and then stack it with the nanoparticle-reinforced PPS adhesive layer (7) of the PPS inner substrate on one side, dry composite, to obtain a composite film. S5. The composite film is cured to obtain aluminum-plastic film.

7. The preparation method according to claim 6, characterized in that, The dry compounding conditions in S1 include being carried out at 80–120°C and 0.4–0.6 MPa. The preheating and drying temperature in S2 is 80-100℃, and the dry compounding conditions include 80-100℃ and 0.5-0.7MPa. The preheating and drying temperature in S4 is 90-110℃, and the dry compounding conditions include 170-190℃ and 0.7-0.9MPa.

8. The preparation method according to claim 6, characterized in that, The S3 double-layer co-extrusion casting process includes: melting and plasticizing the raw materials of nanoparticle-reinforced PPS adhesive layer (7) and elastomer-modified PPS heat-sealing layer (8) through two extruders respectively. The temperature of each section of the extruder is 300-320°C. The molten sheet is extruded through a double-layer co-extrusion die with a die temperature of 310-330°C. The sheet is then cooled and shaped on a cooling roller to obtain the PPS inner layer substrate.

9. The preparation method according to claim 6, characterized in that, The curing process in S4 includes curing in a curing room at 40-60°C for 3-7 days.

10. A solid-state battery, characterized in that, Includes the aluminum-plastic film as described in any one of claims 1-5.

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