Aluminum-plastic film with high flatness of punched shell, preparation method of aluminum-plastic film and lithium ion battery

Abstract

The invention belongs to the technical field of aluminum-plastic films, and particularly relates to an aluminum-plastic film with high flatness during shell punching, a preparation method of the aluminum-plastic film and a lithium ion battery, the aluminum-plastic film comprises a PET film, a first bonding layer, a high-temperature-resistant CPP layer, a second bonding layer, an aluminum foil, a third bonding layer and a CPP film which are sequentially stacked; wherein the high-temperature-resistant CPP layer comprises the following components in parts by mass: 80-90 parts of homo-polypropylene resin, 5-10 parts of silicon dioxide doped POE (Polyolefin Elastomer) resin and 5-10 parts of aluminum nitride inorganic particles.

Description

Technical Field

[0001] The invention belongs to the technical field of aluminum-plastic films, and in particular relates to an aluminum-plastic film with high flatness for punching shells, a preparation method thereof, and a lithium-ion battery. Background Art

[0002] At present, lithium-ion battery technology is becoming more and more mature, and it is widely used in 3C electronic products, power batteries, energy storage and other fields, which has created a greater demand for lithium battery packaging materials. In the field of lithium battery packaging, there are currently three main packaging methods: cylindrical, square and soft pack. Cylindrical and square packaging are mainly made of aluminum shell and steel shell materials, and soft pack is mainly made of aluminum plastic film. Among these three methods, aluminum plastic film soft pack has an increasing market share due to its advantages such as lightweight and safety.

[0003] Aluminum-plastic film is usually composed of an outer substrate layer (nylon film, polyester film), an intermediate aluminum foil layer, and an inner heat-sealing layer (polypropylene film). Depending on the manufacturing process, the punching performance of aluminum-plastic and the performance after punching will also be different. The dry aluminum-plastic film has better punching performance, but the product after punching is more likely to warp toward the substrate layer at the reserved heat-sealing edge. This warping will not only cause great inconvenience to subsequent operations such as regular storage, trimming and shaping, and heat sealing, but the uneven heat-sealing edge will also affect the heat transfer effect of the heat-sealing head, resulting in reduced production efficiency and heat-sealing quality.

[0004] Therefore, how to overcome the warping defect of the dry aluminum-plastic film to improve the flatness is a technical problem that needs to be solved urgently in this field.

[0005] It should be noted that the above information disclosed in this background technology section is only used to understand the background technology of the present application concept, and therefore, the above description is not considered to constitute information of the prior art. Summary of the invention

[0006] The embodiments of the present disclosure at least provide an aluminum-plastic film with high flatness for punching shells, a preparation method thereof, and a lithium-ion battery.

[0007] In the first aspect, an embodiment of the present disclosure provides an aluminum-plastic film with high flatness for punching shells, comprising: a PET film, a first adhesive layer, a high-temperature resistant CPP layer, a second adhesive layer, an aluminum foil, a third adhesive layer and a CPP film stacked in sequence; wherein the high-temperature resistant CPP layer comprises the following components in parts by mass: 80-90 parts of homopolymer polypropylene resin, 5-10 parts of silica-doped POE resin and 5-10 parts of aluminum nitride inorganic particles.

[0008] In an optional embodiment, the CPP film comprises the following components in parts by weight: 80-90 parts of terpolymer polypropylene resin, 5-10 parts of silica-doped POE resin, 2-8 parts of hyperbranched amide resin and 1-5 parts of slip masterbatch.

[0009] In an optional embodiment, the melt flow rate of the homopolymer polypropylene resin is 16-18 g / 10 min.

[0010] In an optional embodiment, the doping content of silica in the silica-doped POE resin is 3-10%.

[0011] In an optional embodiment, the particle size of the inorganic aluminum nitride particles is 50-100 nm.

[0012] In an optional embodiment, the melt flow rate of the terpolymer polypropylene resin is 6-8 g / 10 min.

[0013] In an optional implementation, the thickness of the PET film is 10-15 μm; the thickness of the first adhesive layer, the second adhesive layer and the third adhesive layer is 3-5 μm.

[0014] In an optional embodiment, the thickness of the aluminum foil is 35-45 μm, and after passivation treatment on both sides of the aluminum foil, the matte surface is arranged on the second adhesive layer side, and the bright surface is arranged on the third adhesive layer side.

[0015] In a second aspect, the disclosed embodiment also provides a method for preparing an aluminum-plastic film with high flatness for punching shells as described above, comprising the following steps: step S1, coating an acid-resistant agent on both sides of an aluminum foil, forming an acid-resistant film after passivation, and letting it stand to obtain an aluminum foil with a matte surface and a bright surface; step S2, coating polyurethane glue on one side of the PET film, heating it at high temperature to form a first bonding layer, and then compounding it with a high-temperature resistant CPP layer; step S3, coating polyurethane glue on the matte surface of the aluminum foil, heating it at high temperature to form a second bonding layer, and then compounding it with the other side of the high-temperature resistant CPP layer; step S4, coating polyurethane glue on the bright surface of the aluminum foil, and compounding it with the corona-treated surface of the CPP film after high-temperature heating.

[0016] In a third aspect, the embodiments of the present disclosure further provide a lithium-ion battery which is packaged in a soft package, wherein the packaging material is the aluminum-plastic film with high flatness as described above.

[0017] The beneficial effects of the present invention are that the aluminum-plastic film with high flatness for punching shells and its preparation method, and the lithium-ion battery are provided with a high-temperature resistant CPP layer containing homopolymer polypropylene resin, silicon dioxide-doped POE resin and aluminum nitride inorganic particles, thereby combining the characteristics of the PET film and the high-temperature resistant CPP film, balancing the mechanical strength of the two, thereby overcoming the warping defect of the aluminum-plastic film, so that the aluminum-plastic film can enhance the flatness while meeting the punching depth performance, puncture resistance and wear resistance, and effectively ensuring the quality effect of heat sealing.

[0018] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention are realized and obtained by the structures particularly pointed out in the description and the drawings.

[0019] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 A schematic structural diagram of an aluminum-plastic film with high flatness for punching shells provided in an embodiment of the present disclosure.

[0022] In the figure:

[0023] 1. PET layer; 2. First bonding layer; 3. High temperature resistant CPP layer; 4. Second bonding layer; 5. Aluminum foil; 6. Third bonding layer; 7. CPP film. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work 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," and the like generally refer to the fact that the particular feature, structure, or characteristic following the phrase may be included in at least one embodiment of the present disclosure. Therefore, a particular feature, structure, or characteristic may be included in more than one embodiment of the present disclosure, so that these phrases do not necessarily refer to the same embodiment. As used herein, the terms "example," "exemplary," and the like 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. On the contrary, the use of the terms "example," "exemplary," and the like is intended to present concepts in a concrete manner.

[0026] Herein, example 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 modifying 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 terms used herein are only used to describe specific exemplary configurations and are not intended to be limited. As used herein, the singular articles "one", "an" and "the" may also be intended to include plural forms, unless it is clearly indicated above that this is not the case. The terms "comprise", "include" and "have" are inclusive, and therefore specify the presence of features, steps, operations, elements and / or components, but do not exclude 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 interpreted as necessarily requiring them to be performed in the specific order discussed or shown, unless specifically identified as an execution order. Additional or alternative steps may be adopted.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0029] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0030] See also Figure 1 ,like Figure 1 As shown, an embodiment of the present disclosure provides an aluminum-plastic film with high flatness for punching shells, comprising: a PET film, a first bonding layer, a high-temperature resistant CPP layer, a second bonding layer, an aluminum foil, a third bonding layer and a CPP film stacked in sequence; wherein the high-temperature resistant CPP layer comprises the following components in parts by mass: 80-90 parts of homopolymer polypropylene resin, 5-10 parts of silica-doped POE resin and 5-10 parts of aluminum nitride inorganic particles.

[0031] The disclosed embodiment also provides a method for preparing an aluminum-plastic film with high flatness for punching shells as described above, comprising the following steps: step S1, coating an acid-resistant agent on both sides of an aluminum foil, forming an acid-resistant film after passivation, and letting it stand to obtain an aluminum foil with a matte surface and a bright surface; step S2, coating polyurethane glue on one side of the PET film, heating it at high temperature to form a first bonding layer, and then compounding it with a high-temperature resistant CPP layer; step S3, coating polyurethane glue on the matte surface of the aluminum foil, heating it at high temperature to form a second bonding layer, and then compounding it with the other side of the high-temperature resistant CPP layer; step S4, coating polyurethane glue on the bright surface of the aluminum foil, and compounding it with the corona-treated surface of the CPP film after high-temperature heating.

[0032] The disclosed embodiment also provides a lithium-ion battery, which is packaged in a soft package, wherein the packaging material is the aluminum-plastic film with high flatness as described above.

[0033] The performance of the aluminum-plastic film provided by the present invention is tested according to the following method:

[0034] (1) Puncture performance

[0035] Use Shimadzu AGS-X series electronic universal testing machine to test the puncture performance of the protective layer.

[0036] (2) Punchability

[0037] Punch holes with a shell punching machine. Start punching from 5.0mm, punch 10 samples continuously, check under strong light for no delamination, cracks, or pinholes, then increase by 0.2mm and continue punching for 10 more until it breaks. Record the punching depth before breakage as the limit punching depth.

[0038] (3) Heat sealability

[0039] Using the Japanese Tester Sangyo TP-701-B heat sealer, two 10cm*10cm aluminum-plastic films were heat-sealed at the heat-sealing layer under the conditions of heat-sealing temperature of 190℃, pressure of 0.5mpa, and heat-sealing time of 3s. After the sample cooled to room temperature, the heat-sealing strength was tested using the Shimadzu AGS-X series electronic universal testing machine.

[0040] (4) Flatness of punching shell

[0041] Prepare 130mm*220mm samples by cutting, use a double-pit die to punch holes with a depth of 5.5mm, place them on a marble table for 1 hour, use a steel ruler to measure the height of the four corners, and record the maximum value as the warping height of the shell.

[0042] Example 1

[0043] The invention provides an aluminum-plastic film.

[0044] 60 parts of passivating agent NRC#300 (Nippon Paint (Shanghai) Surface Treatment Agent Co., Ltd.), 20 parts of ethanol and 20 parts of water were mixed and stirred.

[0045] The diluted passivation solution was coated on both sides of a 40u aluminum foil and baked at 250°C for 3 min.

[0046] 90 parts of homopolymer polypropylene resin V30G, 5 parts of silica-doped POE resin (silicon dioxide accounts for 5%), and 5 parts of inorganic particles AlN are added in proportion, melt-filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 15um high-temperature resistant CPP film.

[0047] The glue of product model XH-60W provided by Guangdong Xinhui Chemical Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on one side of the above-mentioned polyethylene terephthalate film, and dried at a temperature of 80°C for 1 minute to form a first bonding layer. The thickness of the first bonding layer was 3um.

[0048] After drying, the adhesive surface of the polyethylene terephthalate film coated with the adhesive layer is thermally laminated with 15um CPP at a lamination temperature of 80°C.

[0049] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended ratio, and then coated on the matte surface of the above-treated aluminum foil, and dried at 80°C for 1 minute to form a second adhesive layer, and the thickness of the second adhesive layer was 3um.

[0050] After drying is completed, the aluminum foil coated with the adhesive layer is thermally laminated with the CPP surface of the previous composite structure at a lamination temperature of 80°C.

[0051] 90 parts of ternary copolymer polypropylene resin TF400, 5 parts of silica-doped POE resin (silicon dioxide accounts for 5%), 2 parts of hyperbranched amide resin, and 3 parts of lubricating masterbatch AB6018PP are added in proportion, melt filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 30μm CPP film.

[0052] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on the bright surface of the above-mentioned aluminum foil, and dried at a temperature of 80°C for 1 minute to form a third bonding layer. The thickness of the third bonding layer was 3um.

[0053] After drying, the aluminum foil coated with the adhesive layer is thermally laminated with 30u CPP at a lamination temperature of 80°C.

[0054] Example 2

[0055] Aluminum-plastic film as provided in Example 1.

[0056] 60 parts of passivating agent NRC#300 (Nippon Paint (Shanghai) Surface Treatment Agent Co., Ltd.), 20 parts of ethanol and 20 parts of water were mixed and stirred.

[0057] The diluted passivation solution was coated on both sides of a 40u aluminum foil and baked at 250°C for 3 min.

[0058] 80 parts of homopolymer polypropylene resin V30G, 10 parts of silica-doped POE resin (silicon dioxide accounts for 5%), and 10 parts of inorganic particles AlN are added in proportion, melt-filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 15μm high-temperature resistant CPP film.

[0059] The glue of product model XH-60W provided by Guangdong Xinhui Chemical Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on one side of the above-mentioned polyethylene terephthalate film, and dried at a temperature of 80°C for 1 minute to form a first bonding layer. The thickness of the first bonding layer was 3um.

[0060] After drying, the adhesive surface of the polyethylene terephthalate film coated with the adhesive layer is thermally laminated with 15um CPP at a lamination temperature of 80°C.

[0061] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended ratio, and then coated on the matte surface of the above-treated aluminum foil, and dried at 80°C for 1 minute to form a second adhesive layer, and the thickness of the second adhesive layer was 3um.

[0062] After drying is completed, the aluminum foil coated with the adhesive layer is thermally laminated with the CPP surface of the previous composite structure at a lamination temperature of 80°C.

[0063] 90 parts of ternary copolymer polypropylene resin TF400, 5 parts of silica-doped POE resin (silicon dioxide accounts for 5%), 2 parts of hyperbranched amide resin, and 3 parts of lubricating masterbatch AB6018PP are added in proportion, melt filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 30μm CPP film.

[0064] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on the bright surface of the above-mentioned aluminum foil, and dried at a temperature of 80°C for 1 minute to form a third bonding layer. The thickness of the third bonding layer was 3um.

[0065] After drying, the aluminum foil coated with the adhesive layer is thermally laminated with 30u CPP at a lamination temperature of 80°C.

[0066] Example 3

[0067] Aluminum-plastic film as provided in Example 1.

[0068] 60 parts of passivating agent NRC#300 (Nippon Paint (Shanghai) Surface Treatment Agent Co., Ltd.), 20 parts of ethanol and 20 parts of water were mixed and stirred.

[0069] The diluted passivation solution was coated on both sides of a 40u aluminum foil and baked at 250°C for 3 min.

[0070] 90 parts of homopolymer polypropylene resin V30G, 5 parts of silica-doped POE resin (silicon dioxide accounts for 5%), and 5 parts of inorganic particles AlN are added in proportion, melt-filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 15μm high-temperature resistant CPP film.

[0071] The glue of product model XH-60W provided by Guangdong Xinhui Chemical Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on one side of the above-mentioned polyethylene terephthalate film, and dried at a temperature of 80°C for 1 minute to form a first bonding layer. The thickness of the first bonding layer was 3um.

[0072] After drying, the adhesive surface of the polyethylene terephthalate film coated with the adhesive layer is thermally laminated with 15um CPP at a lamination temperature of 80°C.

[0073] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended ratio, and then coated on the matte surface of the above-treated aluminum foil, and dried at 80°C for 1 minute to form a second adhesive layer, and the thickness of the second adhesive layer was 3um.

[0074] After drying is completed, the aluminum foil coated with the adhesive layer is thermally laminated with the CPP surface of the previous composite structure at a lamination temperature of 80°C.

[0075] 80 parts of ternary copolymer polypropylene resin TF400, 10 parts of silica-doped POE resin (silicon dioxide accounts for 5%), 8 parts of hyperbranched amide resin, and 2 parts of lubricating masterbatch AB6018PP are added in proportion, melt-filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 30μm CPP film.

[0076] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on the bright surface of the above-mentioned aluminum foil, and dried at a temperature of 80°C for 1 minute to form a third bonding layer. The thickness of the third bonding layer was 3um.

[0077] After drying, the aluminum foil coated with the adhesive layer is thermally laminated with 30u CPP at a lamination temperature of 80°C.

[0078] Example 4

[0079] Aluminum-plastic film as provided in Example 1.

[0080] 60 parts of passivating agent NRC#300 (Nippon Paint (Shanghai) Surface Treatment Agent Co., Ltd.), 20 parts of ethanol and 20 parts of water were mixed and stirred.

[0081] The diluted passivation solution was coated on both sides of a 40u aluminum foil and baked at 250°C for 3 min.

[0082] 80 parts of homopolymer polypropylene resin V30G, 10 parts of silica-doped POE resin (silicon dioxide accounts for 5%), and 10 parts of inorganic particles AlN are added in proportion, melt-filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 15μm high-temperature resistant CPP film.

[0083] The glue of product model XH-60W provided by Guangdong Xinhui Chemical Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on one side of the above-mentioned polyethylene terephthalate film, and dried at a temperature of 80°C for 1 minute to form a first bonding layer. The thickness of the first bonding layer was 3um.

[0084] After drying, the adhesive surface of the polyethylene terephthalate film coated with the adhesive layer is thermally laminated with 15um CPP at a lamination temperature of 80°C.

[0085] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended ratio, and then coated on the matte surface of the above-treated aluminum foil, and dried at 80°C for 1 minute to form a second adhesive layer, and the thickness of the second adhesive layer was 3um.

[0086] After drying is completed, the aluminum foil coated with the adhesive layer is thermally laminated with the CPP surface of the previous composite structure at a lamination temperature of 80°C.

[0087] 80 parts of ternary copolymer polypropylene resin TF400, 10 parts of silica-doped POE resin (silicon dioxide accounts for 5%), 8 parts of hyperbranched amide resin, and 2 parts of lubricating masterbatch AB6018PP are added in proportion, melt-filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 30μm CPP film.

[0088] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on the bright surface of the above-mentioned aluminum foil, and dried at a temperature of 80°C for 1 minute to form a third bonding layer. The thickness of the third bonding layer was 3um.

[0089] After drying, the aluminum foil coated with the adhesive layer is thermally laminated with 30u CPP at a lamination temperature of 80°C.

[0090] Example 5

[0091] Aluminum-plastic film as provided in Example 1.

[0092] 60 parts of passivating agent NRC#300 (Nippon Paint (Shanghai) Surface Treatment Agent Co., Ltd.), 20 parts of ethanol and 20 parts of water were mixed and stirred.

[0093] The diluted passivation solution was coated on both sides of a 40u aluminum foil and baked at 250°C for 3 min.

[0094] 86 parts of homopolymer polypropylene resin V30G, 7 parts of silica-doped POE resin (5% silica), and 7 parts of inorganic particles AlN are added in proportion, melt-filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 15μm high-temperature resistant CPP film.

[0095] The glue of product model XH-60W provided by Guangdong Xinhui Chemical Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on one side of the above-mentioned polyethylene terephthalate film, and dried at a temperature of 80°C for 1 minute to form a first bonding layer. The thickness of the first bonding layer was 3um.

[0096] After drying, the adhesive surface of the polyethylene terephthalate film coated with the adhesive layer is thermally laminated with 15um CPP at a lamination temperature of 80°C.

[0097] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended ratio, and then coated on the matte surface of the above-treated aluminum foil, and dried at 80°C for 1 minute to form a second adhesive layer, and the thickness of the second adhesive layer was 3um.

[0098] After drying is completed, the aluminum foil coated with the adhesive layer is thermally laminated with the CPP surface of the previous composite structure at a lamination temperature of 80°C.

[0099] 80 parts of ternary copolymer polypropylene resin TF400, 10 parts of silica-doped POE resin (silicon dioxide accounts for 5%), 8 parts of hyperbranched amide resin, and 2 parts of lubricating masterbatch AB6018PP are added in proportion, melt-filtered, extruded through a T-die three-layer co-extrusion, cast at high speed, and cooled and crystallized into a 30μm CPP film.

[0100] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on the bright surface of the above-mentioned aluminum foil, and dried at a temperature of 80°C for 1 minute to form a third bonding layer. The thickness of the third bonding layer was 3um.

[0101] After drying, the aluminum foil coated with the adhesive layer is thermally laminated with 30u CPP at a lamination temperature of 80°C.

[0102] Comparative Example 1

[0103] Provided is a method for preparing an aluminum-plastic film.

[0104] 60 parts of passivating agent NRC#300 (Nippon Paint (Shanghai) Surface Treatment Agent Co., Ltd.), 20 parts of ethanol and 20 parts of water were mixed and stirred.

[0105] The diluted passivation solution was coated on both sides of a 40u aluminum foil and baked at 250°C for 3 min.

[0106] The glue of product model XH-60W provided by Guangdong Xinhui Chemical Co., Ltd. was prepared according to the recommended proportion, and after completion, it was coated on the other side of the above-mentioned polyethylene terephthalate film, and dried at a temperature of 90°C for 1 minute to form a first bonding layer. The thickness of the first bonding layer was 3um.

[0107] After drying is completed, the adhesive surface of the polyethylene terephthalate film coated with the adhesive layer is thermally laminated with 15u nylon at a lamination temperature of 80°C.

[0108] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended ratio, and then coated on the matte surface of the above-mentioned aluminum foil, and dried at a temperature of 80°C for 1 minute to form a second adhesive layer, and the thickness of the second adhesive layer was 3um.

[0109] After drying, the aluminum foil coated with the adhesive layer is thermally laminated with 30u CPP at a lamination temperature of 80°C.

[0110] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended proportion. After completion, it was coated on the bright surface of the above-mentioned composite aluminum foil-CPP, and dried at 80°C for 1 minute to form a third bonding layer. The thickness of the third bonding layer was 3um.

[0111] After drying is completed, the aluminum foil coated with the adhesive layer is thermally laminated with the nylon surface of the previous composite structure at a lamination temperature of 80°C.

[0112] Comparative Example 2

[0113] Provided is a method for preparing an aluminum-plastic film.

[0114] 60 parts of passivating agent NRC#300 (Nippon Paint (Shanghai) Surface Treatment Agent Co., Ltd.), 20 parts of ethanol and 20 parts of water were mixed and stirred.

[0115] The diluted passivation solution was coated on both sides of a 40u aluminum foil and baked at 250°C for 3 min.

[0116] The glue of product model XH-60W provided by Guangdong Xinhui Chemical Co., Ltd. was prepared according to the recommended ratio, and after completion, it was coated on the matte surface of the above-mentioned aluminum foil, and dried at a temperature of 80°C for 1 minute to form a first bonding layer. The thickness of the first bonding layer was 3um.

[0117] After drying, the aluminum foil coated with the adhesive layer is thermally laminated with 30u CPP at a lamination temperature of 80°C.

[0118] The glue of product model LN-1212 provided by Chengdu Kecheng Fine Chemical Technology Co., Ltd. was prepared according to the recommended proportion. After completion, it was coated on the bright surface of the above-mentioned composite aluminum foil-CPP, and dried at a temperature of 80°C for 1 minute to form a second adhesive layer. The thickness of the second adhesive layer was 3um.

[0119] After drying is completed, the aluminum foil coated with the adhesive layer is thermally laminated with nylon at a lamination temperature of 80°C.

[0120] Table 1 Performance test results of aluminum-plastic films provided by Examples 1-5 and Comparative Examples 1-3

[0121]

[0122]

[0123] Specifically, compared with Comparative Example 1, the embodiment provided by the present invention replaces the nylon layer compounded with PET with a high-temperature resistant CPP layer. There is a strong hydrogen bond between the nylon molecular chains, which can effectively transmit and disperse the tensile force, so it has good toughness and is not easy to deform. On the other hand, the high-temperature resistant CPP film to which nanoparticles are added, in the elastic stretching stage, the nanoparticles can act as physical cross-linking points, limit the excessive movement of the molecular chains, thereby narrowing the elastic range, so it is easy to reach the yield point and perform plastic deformation, and the material will also relax stress over time, making the aluminum-plastic film smoother as a whole.

[0124] Specifically, compared with Comparative Example 2, the embodiment provided by the present invention is compounded with an additional PET layer. In this embodiment, the nylon film is replaced with a high-temperature resistant CPP film. Under normal temperature conditions, the puncture resistance of the nylon film may be better than that of the high-temperature resistant CPP film. There are strong hydrogen bonds in the molecular structure of the nylon film, which makes it have a higher degree of crystallinity and better mechanical properties at room temperature, and can effectively resist puncture. However, the molecular chain interaction force of the CPP film at room temperature is relatively weak, and the crystallinity is relatively low, so the puncture resistance at room temperature may be slightly poor. Therefore, on the basis of replacing the nylon layer with the high-temperature resistant CPP film, an additional layer of PET film is compounded, and the PET molecular chain is composed of rigid benzene rings and flexible ethylene glycol segments. This structure gives the PET film a certain toughness and strength. Higher crystallinity can improve the puncture resistance of the PET film. The crystalline region can enhance the intermolecular force, and when subjected to puncture force, the crystalline part can effectively disperse stress. Therefore, this embodiment adds a PET layer to make up for the lack of puncture resistance after replacing the nylon layer.

[0125] In summary, the aluminum-plastic film with high flatness for punching shells and its preparation method, and the lithium-ion battery are provided with a high-temperature resistant CPP layer containing homopolymer polypropylene resin, silica-doped POE resin and aluminum nitride inorganic particles, so as to combine the characteristics of PET film and high-temperature resistant CPP film, balance the mechanical strength of the two, thereby overcoming the warping defect of the aluminum-plastic film, so that the aluminum-plastic film can enhance the flatness while meeting the punching depth performance, puncture resistance and wear resistance, and effectively ensure the quality effect of heat sealing.

[0126] Based on the above ideal embodiments of the present invention, the relevant staff can make various changes and modifications without departing from the technical concept of the present invention through the above description. The technical scope of the present invention is not limited to the contents of the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A high-flatness aluminum-plastic film for punching shells, characterized in that: include: A PET film, a first adhesive layer, a high temperature resistant CPP layer, a second adhesive layer, an aluminum foil, a third adhesive layer and a CPP film are sequentially stacked; in The high temperature resistant CPP layer comprises the following components in parts by mass: 80-90 parts of homopolymer polypropylene resin, 5-10 parts of silicon dioxide doped POE resin and 5-10 parts of aluminum nitride inorganic particles.

2. The aluminum-plastic film with high flatness for punching shells as claimed in claim 1, characterized in that: The CPP film comprises the following components in parts by weight: 80-90 parts of ternary copolymer polypropylene resin, 5-10 parts of silica-doped POE resin, 2-8 parts of hyperbranched amide resin and 1-5 parts of slip masterbatch.

3. The aluminum-plastic film with high flatness for punching shells as claimed in claim 1, characterized in that: The melt flow rate of the homopolymer polypropylene resin is 16-18 g / 10 min.

4. The aluminum-plastic film with high flatness for punching shells as claimed in claim 1, characterized in that: The doping content of silicon dioxide in the silicon dioxide-doped POE resin is 3-10%.

5. The aluminum-plastic film with high flatness for punching shells as claimed in claim 1, characterized in that: The particle size of the aluminum nitride inorganic particles is 50-100 nm.

6. The aluminum-plastic film with high flatness for punching shells as claimed in claim 1, characterized in that: The melt flow rate of the terpolymer polypropylene resin is 6-8 g / 10 min.

7. The aluminum-plastic film with high flatness for punching shells as claimed in claim 1, characterized in that: The thickness of the PET film is 10-15 μm; The thickness of the first bonding layer, the second bonding layer and the third bonding layer is 3-5 μm.

8. The aluminum-plastic film with high flatness for punching shells as claimed in claim 1, characterized in that: The thickness of the aluminum foil is 35-45 μm, and after passivation treatment on both sides of the aluminum foil, the matte side is arranged on the second bonding layer side, and the bright side is arranged on the third bonding layer side.

9. A method for preparing an aluminum-plastic film with high flatness for punching shells as claimed in any one of claims 1 to 8, characterized in that: The steps include: Step S1, coating an acid-resistant agent on both sides of the aluminum foil to form an acid-resistant film after passivation, and letting it stand to obtain an aluminum foil with a matte surface and a bright surface; Step S2, applying polyurethane glue on one side of the PET film, heating at high temperature to form a first bonding layer and then compounding it with the high temperature resistant CPP layer; Step S3, applying polyurethane glue to the matte surface of the aluminum foil, heating at high temperature to form a second adhesive layer, and then laminating it with the other side of the high temperature resistant CPP layer; Step S4, applying polyurethane glue to the bright surface of the aluminum foil, and then laminating it with the corona-treated surface of the CPP film after high-temperature heating.

10. A lithium ion battery, characterized in that: Soft package packaging is adopted, and the packaging material is the aluminum-plastic film with high flatness as claimed in any one of claims 1 to 8.

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