Composite al-plastic film, preparation method and application thereof

Abstract

This invention provides a composite aluminum-plastic film, its preparation method, and its application. The composite aluminum-plastic film includes a basic layer structure, which comprises an outer sealing layer, a first adhesive layer, an aluminum foil layer, a second adhesive layer, and a heat-sealing layer stacked sequentially. In the basic layer structure, one or more layers other than the aluminum foil layer contain a heat-sensitive material; alternatively, the composite aluminum-plastic film further includes at least one functional layer formed of a heat-sensitive material, with each functional layer located on the surface of the basic layer structure or between any two layers. The composite aluminum-plastic film has an average thermal conductivity of k1 in a first temperature range and an average thermal conductivity of k2 in a second temperature range. k1 is 0.10–0.45 W / (m·K), and (k2–k1) / k1 ≥ 30%. The temperature in the first temperature range is 50–120°C, and the temperature in the second temperature range is higher than 120°C.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery packaging technology, and more specifically, to a composite aluminum-plastic film, its preparation method, and its application. Background Technology

[0002] Soft-pack batteries are increasingly favored due to their light weight, high space utilization, and resulting energy density advantages. Their excellent performance in fast charging, battery system integration, and exterior design makes them a preferred choice for new energy passenger vehicles. Among these, aluminum-plastic film is a key material for the outer packaging of soft-pack batteries. From the outside to the inside, it typically consists of a resin layer (outer layer), an aluminum foil layer (middle layer), and a heat-sealing layer (inner layer), with each layer bonded together using adhesive layers.

[0003] However, there is still significant room for improvement in the safety performance of pouch batteries. To minimize the risk of thermal runaway, the thermal conductivity of the aluminum-plastic film needs to be freely varied across different temperature ranges to improve the battery's thermal conductivity. Depending on the temperature field, the internal materials of the pouch battery can be utilized for either heat absorption or dissipation, thus preventing the battery from catching fire or exploding when the external ambient temperature changes.

[0004] Therefore, researching and developing a composite aluminum-plastic film and its preparation method is of great significance for improving the thermal conductivity of pouch batteries and preventing them from catching fire and exploding. Summary of the Invention

[0005] The main objective of this invention is to provide a composite aluminum-plastic film, its preparation method, and its application, in order to solve the problem that in the prior art, soft-pack batteries have small differences in heat absorption and heat dissipation capabilities under different temperature ranges (including 50-120°C and above 120°C), resulting in poor thermal conductivity and a tendency to catch fire and explode.

[0006] To achieve the above objectives, the present invention provides a composite aluminum-plastic film, which includes a basic layer structure comprising an outer sealing layer, a first adhesive layer, an aluminum foil layer, a second adhesive layer, and a heat-sealing layer stacked sequentially. The basic layer structure may contain one or more layers other than the aluminum foil layer containing a heat-sensitive material; alternatively, the composite aluminum-plastic film may further include at least one functional layer formed of a heat-sensitive material, with each functional layer located on the surface of the basic layer structure or between any two layers. The composite aluminum-plastic film has an average thermal conductivity of k1 in a first temperature range and an average thermal conductivity of k2 in a second temperature range, where k1 is 0.15–0.45 W / (m·K) and (k2-k1) / k1 ≥ 30%. The temperature in the first temperature range is 50–120°C, and the temperature in the second temperature range is higher than 120°C.

[0007] Furthermore, the thermistor material is selected from inorganic and / or organic thermistors; the inorganic thermistor material is selected from one or more of the group consisting of silicon carbide, silicon nitride, aluminum silicate, and aluminum nitride; the organic thermistor material is selected from C4 to C4. 20 Aliphatic hydrocarbons, C6-C 12 It consists of one or more of the following: fatty acid compounds, C1-C8 fatty ester compounds, liquid crystal polyurethane elastomers, liquid crystal acrylate elastomers, and polyamines with a weight average molecular weight of 3,000-50,000.

[0008] Furthermore, when the thermosensitive material is a mixture of inorganic and organic thermosensitive materials, the thermosensitive material is a mixture of silicon nitride and liquid crystal polyurethane elastomer, preferably a mixture of silicon nitride and liquid crystal polyurethane elastomer in a weight ratio of 1:(1-10); and / or, the thermosensitive material is a mixture of silicon carbide and liquid crystal acrylate elastomer, preferably a mixture of silicon carbide and liquid crystal acrylate elastomer in a weight ratio of 1:(1-10); when the thermosensitive material is an inorganic thermosensitive material, the thermosensitive material is a mixture of silicon carbide and aluminum silicate, preferably a mixture of silicon carbide and aluminum silicate in a weight ratio of 1:(1-15); and / or, the thermosensitive material is a mixture of silicon nitride and aluminum nitride, preferably a mixture of silicon nitride and aluminum nitride in a weight ratio of 1:(1-15); when the thermosensitive material is an organic thermosensitive material, the thermosensitive material is C4-C 20 A mixture of aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomers, preferably C4 to C5 compounds in a weight ratio of 1:(0.1 to 2). 20 A mixture of aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomers; and / or, the thermosensitive material is C6 to C6. 12 A mixture of fatty acid compounds and liquid crystal polyurethane elastomers, preferably C6 to C4 compounds in a weight ratio of 1:(0.1 to 2). 12 A mixture of fatty acid compounds and liquid crystal polyurethane elastomers.

[0009] Furthermore, the composite aluminum-plastic film also includes at least one functional layer, the functional layer having a weight percentage of 0.5 to 15 wt% based on the total weight of the basic layer structure; and / or, the thickness of the functional layer being 10 to 50 μm.

[0010] Further, the outer sealing layer is a composite layer of heat-sensitive material and polyamide fiber, preferably with a weight ratio of heat-sensitive material to polyamide fiber of 1:(1-10); and / or, the heat-sealing layer is a composite layer of heat-sensitive material and polyolefin, preferably with a weight ratio of heat-sensitive material to polyolefin of 1:(0.5-2); and / or, the first adhesive layer is a composite layer of heat-sensitive material and polyurethane adhesive, preferably with a weight ratio of heat-sensitive material to polyurethane adhesive of 1:(1-10); and / or, the second adhesive layer is a composite layer of heat-sensitive material and polyolefin adhesive, preferably with a weight ratio of heat-sensitive material to polyolefin adhesive of 1:(1-10).

[0011] Furthermore, the outer sealing layer has a thickness of 8–50 μm, the first adhesive layer has a thickness of 2–10 μm, the aluminum foil layer has a thickness of 10–100 μm, the second adhesive layer has a thickness of 3–15 μm, the heat-sealing layer has a thickness of 15–80 μm, and the functional layer has a thickness of 10–50 μm.

[0012] Furthermore, the outer sealing layer has a thickness of 8–100 μm, the first adhesive layer has a thickness of 2–60 μm, the aluminum foil layer has a thickness of 10–100 μm, the second adhesive layer has a thickness of 3–65 μm, and the heat-sealing layer has a thickness of 15–130 μm.

[0013] To achieve the above objectives, another aspect of the present invention provides a method for preparing the composite aluminum-plastic film provided in this application. The method includes: step S1, preparing each layer in the basic layer structure; step S2, adding a heat-sensitive material when preparing one or more optional layers other than the aluminum foil layer in the basic layer structure, or coating the heat-sensitive material on the surface of the basic layer structure or between any two optional layers, and obtaining a laminated structure after pressing; step S3, heat-treating the laminated structure to obtain the composite aluminum-plastic film.

[0014] Furthermore, the pressure of the pressing process is 0.10–0.45 MPa, the temperature is 50–70 °C, and the time is 5–45 min; and / or, the temperature of the heat treatment is 30–50 °C, and the time is 3–10 days.

[0015] Furthermore, the thermosensitive material is selected from inorganic thermosensitive materials and / or organic thermosensitive materials; preferably, the average particle size of the inorganic thermosensitive material is 10-50 nm.

[0016] Furthermore, when preparing one or more optional layers other than the aluminum foil layer in the basic layer structure, a heat-sensitive material is added. The outer sealing layer is a composite layer made by mixing and casting the heat-sensitive material and polyamide fiber; and / or, the heat-sealing layer is a composite layer made by mixing and casting the heat-sensitive material and polyolefin; and / or, the first adhesive layer is a composite layer made by mixing and casting the heat-sensitive material and polyurethane adhesive; and the second adhesive layer is a composite layer made by mixing and casting the heat-sensitive material and polyolefin adhesive.

[0017] Furthermore, when the heat-sensitive material is a mixture of silicon nitride and liquid crystal polyurethane elastomer, the pressure of the pressing process is 0.25–0.45 MPa, the temperature is 55–60 °C, and the time is 15–45 min; the temperature of the heat treatment is 40–45 °C, and the time is 3–10 days; and / or, the heat-sensitive material is C4–C 20 When mixing aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomers, the pressure of the pressing process is 0.15-0.35 MPa, the temperature is 40-60℃, and the time is 5-35 min. The temperature of the heat treatment is 40-45℃, and the time is 3-8 days.

[0018] Furthermore, when the thermosensitive material is coated onto the surface of the base layer structure or optionally between two layers, and the thermosensitive material is a mixture of silicon nitride and liquid crystal polyurethane elastomer, the pressing process is carried out at a pressure of 0.35–0.40 MPa, a temperature of 55–60 °C, and a time of 30–45 min, and the heat treatment is carried out at a temperature of 40–45 °C for 5–7 days; and / or, the thermosensitive material is C4–C 20 When mixing aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomers, the pressure of the pressing process is 0.15-0.20 MPa, the temperature is 40-50℃, and the time is 10-25 min. The temperature of the heat treatment is 40-45℃, and the time is 3-8 days.

[0019] Furthermore, the heat treatment process is followed by a settling process; preferably, the settling temperature is 20-25°C and the time is 1-7 days.

[0020] Another aspect of the present invention provides an application of the composite aluminum-plastic film provided in this application, or the composite aluminum-plastic film prepared by the method provided in this application, in the field of lithium-ion battery packaging.

[0021] Compared with traditional aluminum-plastic films, the composite aluminum-plastic film provided in this application, using the technical solution of the present invention, also includes a thermosensitive material or a functional layer formed by a thermosensitive material. The addition of the thermosensitive material or the setting of the functional layer can improve the thermosensitive performance of the composite aluminum-plastic film, enabling the soft-pack battery to have stronger heat absorption capacity in the first temperature range of 50-120°C and stronger heat dissipation capacity in the second temperature range above 120°C. That is, by adjusting the balance between heat absorption and heat dissipation of the functional layer in different temperature ranges, the thermal conductivity of the soft-pack battery under different temperature environments is improved, thereby significantly improving the safety of the soft-pack battery.

[0022] Compared to other ranges, limiting the difference between the average thermal conductivity of the first temperature range and the average thermal conductivity of the second temperature range to the above range (i.e., strictly controlling the value range of (k2-k1) / k1 within the above range) is beneficial to improving the thermal conductivity of the pouch battery under different temperature environments, thereby improving the safety of the pouch battery. Attached Figure Description

[0023] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0024] Figure 1 A schematic diagram of the laminated structure of the composite aluminum-plastic film prepared in Embodiment 1 of this application is shown;

[0025] Figure 2 A schematic diagram of the laminated structure of the composite aluminum-plastic film prepared in Embodiment 4 of this application is shown.

[0026] The above figures include the following reference numerals:

[0027] 10. Outer sealing layer; 20. First adhesive layer; 30. Aluminum foil layer; 40. Second adhesive layer; 50. Heat-sealing layer; 60. Functional layer. Detailed Implementation

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0029] As described in the background section, existing pouch batteries exhibit relatively small differences in heat absorption and dissipation capabilities across different temperature ranges (including 50–120°C and above 120°C), making it difficult to improve their thermal conductivity and prevent fires and explosions. To address these technical problems, this application provides a composite aluminum-plastic film, such as… Figure 1 As shown, the composite aluminum-plastic film includes a basic layer structure, which comprises an outer sealing layer 10, a first adhesive layer 20, an aluminum foil layer 30, a second adhesive layer 40, and a heat-sealing layer 50 stacked sequentially. In the basic layer structure, one or more layers other than the aluminum foil layer 30 may contain a heat-sensitive material, or, as shown... Figure 2As shown, the composite aluminum-plastic film also includes at least one functional layer 60 formed of a heat-sensitive material, and each functional layer 60 is located on the surface of the basic layer structure or between any two layers; the average thermal conductivity of the composite aluminum-plastic film in the first temperature range is k1, and the average thermal conductivity in the second temperature range is k2, where k1 is 0.15 to 0.45 W / (m·k) and (k2-k1) / k1≥30%; the temperature in the first temperature range is 50 to 120℃, and the temperature in the second temperature range is higher than 120℃.

[0030] Traditional aluminum-plastic film consists of only an outer sealing layer 10, a first adhesive layer 20, an aluminum foil layer 30, a second adhesive layer 40, and a heat-sealing layer 50, stacked sequentially. The outer sealing layer 10 protects the intermediate aluminum foil layer 30 from scratches and increases its ductility, requiring good impact resistance and insulation. The aluminum foil layer 30 prevents moisture from entering the battery and electrolyte from seeping out, requiring good barrier properties, formability, and double-sided composite processing performance. The heat-sealing layer 50 requires good heat-sealing performance and barrier properties against water and solvents. The first adhesive layer 20 and the second adhesive layer 40 bond the various layers together.

[0031] Compared with traditional aluminum-plastic film, the composite aluminum-plastic film provided in this application also includes a thermosensitive material or a functional layer 60 formed of a thermosensitive material. The addition of the thermosensitive material or the setting of the functional layer 60 can improve the thermosensitive performance of the composite aluminum-plastic film, enabling the soft-pack battery to have stronger heat absorption capacity in the first temperature range of 50-120°C and stronger heat dissipation capacity in the second temperature range above 120°C. That is, by adjusting the balance between heat absorption and heat dissipation of the functional layer 60 in different temperature ranges, the thermal conductivity of the soft-pack battery under different temperature environments is improved, thereby significantly improving the safety of the soft-pack battery.

[0032] Compared to other ranges, limiting the difference between the average thermal conductivity of the first temperature range and the average thermal conductivity of the second temperature range to the above range (i.e., strictly controlling the value range of (k2-k1) / k1 within the above range) is beneficial to improving the thermal conductivity of the pouch battery under different temperature environments, thereby improving the safety of the pouch battery.

[0033] In a preferred embodiment, the thermistor material includes, but is not limited to, inorganic thermistors and / or organic thermistors; the inorganic thermistor material includes, but is not limited to, one or more of the group consisting of silicon carbide, silicon nitride, aluminum silicate, and aluminum nitride; the organic thermistor material includes, but is not limited to, C4-C4. 20 Aliphatic hydrocarbons, C6-C 12The material comprises one or more of the following: fatty acid compounds, C1-C8 fatty ester compounds, liquid crystal polyurethane elastomers, liquid crystal acrylate elastomers, and polyamines with a weight-average molecular weight of 3000-50000. Compared to other ranges, using the above-mentioned types of thermosensitive materials is beneficial for further improving the thermosensitive performance of the composite aluminum-plastic film, further improving the thermal conductivity of the pouch battery under different temperature environments, and thus further improving the safety of the pouch battery.

[0034] In a preferred embodiment, when the thermosensitive material is a mixture of inorganic and organic thermosensitive materials, the thermosensitive material is a mixture of silicon nitride and liquid crystal polyurethane elastomer, preferably a mixture of silicon nitride and liquid crystal polyurethane elastomer in a weight ratio of 1:(1-10); and / or, the thermosensitive material is a mixture of silicon carbide and liquid crystal acrylate elastomer, preferably a mixture of silicon carbide and liquid crystal acrylate elastomer in a weight ratio of 1:(1-10). Compared to other types, using the above-mentioned mixtures as the thermosensitive material is beneficial to leveraging the synergistic effect of inorganic and organic thermosensitive materials, further improving the thermosensitive performance of the composite aluminum-plastic film, further improving the thermal conductivity of the pouch battery under different temperature environments, and thus further improving the safety of the pouch battery; at the same time, compared to other ranges, limiting the weight ratio of each component in the above-mentioned mixtures within the above range is beneficial to further leveraging the synergistic effect of inorganic and organic thermosensitive materials, further improving the thermosensitive performance of the composite aluminum-plastic film, further improving the thermal conductivity of the pouch battery under different temperature environments, and thus further improving the safety of the pouch battery.

[0035] In a preferred embodiment, when the thermistor is an inorganic thermistor, it is a mixture of silicon carbide and aluminum silicate, preferably a mixture of silicon carbide and aluminum silicate in a weight ratio of 1:(1-15); and / or, the thermistor is a mixture of silicon nitride and aluminum nitride, preferably a mixture of silicon nitride and aluminum nitride in a weight ratio of 1:(1-15). Compared to other types, using the above-mentioned mixtures as the thermistor is beneficial to further improve the thermistor performance of the composite aluminum-plastic film, further improve the thermal conductivity of the pouch battery under different temperature environments, and thus further improve the safety of the pouch battery; at the same time, compared to other ranges, limiting the weight ratio of each component in the above-mentioned mixtures within the above-mentioned range is beneficial to further enhance the thermistor performance of the inorganic thermistor, further improve the thermistor performance of the composite aluminum-plastic film, further improve the thermal conductivity of the pouch battery under different temperature environments, and thus further improve the safety of the pouch battery.

[0036] In a preferred embodiment, when the thermosensitive material is an organic thermosensitive material, the thermosensitive material is C4~C 20A mixture of aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomers, preferably C4 to C5 compounds in a weight ratio of 1:(0.1 to 2). 20 A mixture of aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomers; and / or, the thermosensitive material is C6 to C6. 12 A mixture of fatty acid compounds and liquid crystal polyurethane elastomers, preferably C6 to C4 compounds in a weight ratio of 1:(0.1 to 2). 12 This is a mixture of fatty acid compounds and liquid crystal polyurethane elastomers. Compared to other types, using this mixture as the thermosensitive material is beneficial for further improving the thermosensitive performance of the composite aluminum-plastic film, further improving the thermal conductivity of the pouch battery under different temperature environments, and thus further improving the safety of the pouch battery. Furthermore, compared to other ranges, limiting the weight ratio of each component in the above-mentioned mixture within the above range is beneficial for further maximizing the thermosensitive performance of the organic thermosensitive material, further improving the thermosensitive performance of the composite aluminum-plastic film, further improving the thermal conductivity of the pouch battery under different temperature environments, and thus further improving the safety of the pouch battery.

[0037] In a preferred embodiment, the composite aluminum-plastic film further includes at least one functional layer 60, the weight percentage of which, based on the total weight of the basic layer structure, is 0.5–15 wt%. The weight percentage of the functional layer 60 includes, but is not limited to, the above range. Limiting it within this range is beneficial for improving the adhesion between the functional layer 60 and other layers, and for suppressing the phenomenon of easy delamination between layers. Simultaneously, it is beneficial for further improving the thermal sensitivity of the composite aluminum-plastic film, further improving the thermal conductivity of the pouch battery under different temperature environments, and thus further improving the safety of the pouch battery.

[0038] In a preferred embodiment, the thickness of the functional layer 60 is 10–50 μm. The thickness of the functional layer 60 includes, but is not limited to, the above range. Limiting it to this range helps improve the adhesion between the functional layer 60 and other layers, and helps suppress the phenomenon of easy delamination between layers. Simultaneously, it helps to further improve the thermal sensitivity of the composite aluminum-plastic film, further improve the thermal conductivity of the pouch battery under different temperature environments, and thus further improve the safety of the pouch battery.

[0039] In this application, the heat-sensitive material can also be used as one or more layers of the outer sealing layer 10, heat sealing layer 50, first adhesive layer 20, and second adhesive layer 40.

[0040] In a preferred embodiment, the outer sealing layer 10 is a composite layer of a thermosensitive material and polyamide fiber. When the outer sealing layer 10 contains a thermosensitive material component, it can promptly conduct the heat generated inside the battery to the outside of the battery, thereby improving the heat dissipation capacity of the pouch battery. At the same time, it helps to reduce the absorption of external heat by the outer sealing layer 10, which helps to lower the internal temperature of the pouch battery, thereby improving the safety of the pouch battery.

[0041] In order to improve the thermal performance of the outer sealing layer 10 while maintaining its function of protecting the intermediate aluminum foil layer 30 from scratches and increasing the ductility of the aluminum foil, as well as its good impact resistance and insulation, preferably, the weight ratio of the thermal material to the polyamide fiber is 1:(1-10) based on the total weight of the outer sealing layer 10.

[0042] In a preferred embodiment, the heat-sealing layer 50 is a composite layer of a thermosensitive material and a polyolefin. When the heat-sealing layer 50 contains a thermosensitive material component, it can promptly conduct the heat from the internal cells of the pouch battery to the outside of the composite aluminum-plastic film, thereby improving the heat dissipation capacity of the pouch battery and enhancing its safety.

[0043] In order to improve the thermosensitive properties of the heat-sealing layer 50 while maintaining good barrier properties against water and electrolyte, preferably, the weight ratio of the thermosensitive material to the polyolefin is 1:(0.5-2) based on the total weight of the heat-sealing layer 50.

[0044] In a preferred embodiment, the first adhesive layer 20 is a composite layer of a heat-sensitive material and a polyurethane adhesive. When the first adhesive layer 20 contains a heat-sensitive material component, it can promptly conduct the heat from the internal cells of the pouch battery to the outside of the composite aluminum-plastic film, thereby improving the heat dissipation capacity of the pouch battery and enhancing its safety.

[0045] In order to improve the thermal performance of the first adhesive layer 20 while maintaining good adhesion, preferably, the weight ratio of the thermal material to the polyurethane adhesive is 1:(1 to 10), more preferably 1:(1 to 5), based on the total weight of the first adhesive layer 20.

[0046] In a preferred embodiment, the second adhesive layer 40 is a composite layer of a heat-sensitive material and a polyolefin adhesive. When the second adhesive layer 40 contains a heat-sensitive material component, it can promptly conduct the heat from the internal cells of the pouch battery to the outside of the composite aluminum-plastic film, thereby improving the heat dissipation capacity of the pouch battery and enhancing its safety.

[0047] In order to improve the heat-sensitive properties of the second adhesive layer 40 while maintaining the good adhesion of the first adhesive layer 20, preferably, the weight ratio of the heat-sensitive material to the polyolefin adhesive is 1:(1 to 10), more preferably 1:(1 to 5), based on the total weight of the second adhesive layer 40.

[0048] In a preferred embodiment, the outer sealing layer 10 has a thickness of 8–50 μm, the first adhesive layer 20 has a thickness of 2–10 μm, the aluminum foil layer 30 has a thickness of 10–100 μm, the second adhesive layer 40 has a thickness of 3–15 μm, the heat-sealing layer 50 has a thickness of 15–80 μm, and the functional layer 60 has a thickness of 10–50 μm. The thicknesses of each layer in the composite aluminum-plastic film include, but are not limited to, the above ranges. Limiting them to these ranges helps to better utilize the composite aluminum-plastic film's thermosensitive properties, its ability to isolate oxygen and moisture, and its ability to prevent electrolyte leakage, thereby improving the overall performance of the composite aluminum-plastic film.

[0049] In another preferred embodiment, the outer sealing layer 10 has a thickness of 8–100 μm, the first adhesive layer 20 has a thickness of 2–60 μm, the aluminum foil layer 30 has a thickness of 10–100 μm, the second adhesive layer 40 has a thickness of 3–65 μm, and the heat-sealing layer 50 has a thickness of 15–130 μm. The thickness of each layer in the composite aluminum-plastic film includes, but is not limited to, the above ranges. Limiting them to these ranges helps to better utilize the composite aluminum-plastic film's heat-sensitive properties, its ability to isolate oxygen and moisture, and its ability to prevent electrolyte leakage, thereby improving the overall performance of the composite aluminum-plastic film.

[0050] The second aspect of this application also provides a method for preparing a composite aluminum-plastic film, the method comprising: step S1, preparing each layer in a basic layer structure; step S2, adding a heat-sensitive material when preparing one or more optional layers other than the aluminum foil layer 30 in the basic layer structure, or coating the heat-sensitive material on the surface of the basic layer structure or between optional two layers, and obtaining a laminated structure after pressing; step S3, heat-treating the laminated structure to obtain a composite aluminum-plastic film.

[0051] After pressing the above layers together, a laminated structure is obtained. The laminated structure is then heat-treated to form an outer sealing layer 10, a first adhesive layer 20, an aluminum foil layer 30, a second adhesive layer 40, and a heat-sealing layer 50, which are sequentially stacked, thus obtaining a composite aluminum-plastic film. This composite aluminum-plastic film also includes at least one functional layer 60. Compared to traditional aluminum-plastic films, the composite aluminum-plastic film provided in this application further incorporates a thermosensitive material or includes a functional layer formed from a thermosensitive material. The addition of this thermosensitive material or the establishment of the functional layer can improve the thermosensitive performance of the composite aluminum-plastic film, enabling the soft-pack battery to have stronger heat absorption capacity in the first temperature range of 50–120°C and stronger heat dissipation capacity in the second temperature range above 120°C. In other words, by controlling the balance between heat absorption and heat dissipation of the functional layer in different temperature ranges, the thermal conductivity of the soft-pack battery under different temperature environments is improved, thereby significantly improving the safety of the soft-pack battery.

[0052] In a preferred embodiment, the thermosensitive material is coated using a planar blade coating method. This coating method is simple to operate, has low preparation cost, and is suitable for large-scale production.

[0053] In a preferred embodiment, the pressure during the lamination process is 0.10–0.45 MPa, the temperature is 50–70°C, and the time is 5–45 min. The pressure, temperature, and time of the lamination process include, but are not limited to, the above ranges. Limiting them to these ranges facilitates a tighter adhesion between the layers during the lamination process, thereby improving the overall performance of the composite aluminum-plastic film.

[0054] In a preferred embodiment, the heat treatment temperature is 30–50°C, and the time is 3–10 days. The heat treatment temperature and time include, but are not limited to, the above ranges. Limiting them to the above ranges is beneficial for better utilizing the heat-sensitive properties, oxygen and moisture isolation properties, and electrolyte leakage prevention properties of the composite aluminum-plastic film, thereby improving the overall performance of the composite aluminum-plastic film.

[0055] In a preferred embodiment, the thermosensitive material includes, but is not limited to, inorganic thermosensitive materials and / or organic thermosensitive materials; preferably, the average particle size of the inorganic thermosensitive material is 10–50 nm. The average particle size of the inorganic thermosensitive material includes, but is not limited to, the above range, and limiting it to the above range is beneficial to improving its processability (e.g., facilitating casting), thereby facilitating material composite molding.

[0056] In a preferred embodiment, a heat-sensitive material is added when preparing one or more optional layers other than the aluminum foil layer 30 in the basic layer structure. The outer sealing layer 10 is a composite layer made of heat-sensitive material and polyamide fiber through mixing and casting; and / or, the heat-sealing layer 50 is a composite layer made of heat-sensitive material and polyolefin through mixing and casting; and / or, the first adhesive layer 20 is a composite layer made of heat-sensitive material and polyurethane adhesive through mixing and casting; and the second adhesive layer 40 is a composite layer made of heat-sensitive material and polyolefin adhesive through mixing and casting.

[0057] Different processing techniques are employed for different composite layers. In a preferred embodiment, when the thermosensitive material is a mixture of silicon nitride and liquid crystal polyurethane elastomer, the pressing process is carried out at a pressure of 0.25–0.45 MPa, a temperature of 55–60°C, and a time of 15–45 min; the heat treatment is carried out at a temperature of 40–45°C and a time of 3–10 days; and / or, the thermosensitive material is C4–C 20 When using a mixture of aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomers, the pressing process involves a pressure of 0.15–0.35 MPa, a temperature of 40–60°C, and a time of 5–35 min; the heat treatment involves a temperature of 40–45°C and a time of 3–8 days. The pressure, temperature, and time of the pressing process, as well as the temperature and time of the heat treatment, are not limited to the ranges mentioned above. Limiting these ranges helps to better utilize the thermosensitive properties, oxygen and moisture barrier properties, and electrolyte leakage prevention properties of the composite aluminum-plastic film, thereby improving its overall performance.

[0058] Different processing techniques are employed for functional layers 60 with different compositions. In a preferred embodiment, a thermosensitive material is coated onto the surface of the base layer structure or optionally between two layers. When the thermosensitive material is a mixture of silicon nitride and liquid crystal polyurethane elastomer, the pressing process is carried out at a pressure of 0.35–0.40 MPa, a temperature of 55–60°C, and a time of 30–45 min; the heat treatment temperature is 40–45°C, and the time is 5–7 days; and / or, the thermosensitive material is C4–C 20 When using a mixture of aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomers, the pressing process involves a pressure of 0.15–0.20 MPa, a temperature of 40–50°C, and a time of 10–35 min; the heat treatment involves a temperature of 40–45°C and a time of 3–8 days. The pressure, temperature, and time of the pressing process, as well as the temperature and time of the heat treatment, are not limited to the ranges mentioned above. Limiting these ranges helps to better utilize the thermosensitive properties, oxygen and moisture barrier properties, and electrolyte leakage prevention properties of the composite aluminum-plastic film, thereby improving its overall performance.

[0059] In a preferred embodiment, the heat treatment process is followed by a settling process. This settling process after heat treatment allows for more complete bonding of the heat-sensitive materials, thus improving the overall performance of the composite aluminum-plastic film.

[0060] To further ensure a smooth fit between the functional layer 60 and the adjacent layers, and to conserve equipment resources, the settling temperature is preferably 20–25°C, and the settling time is 1–7 days.

[0061] The third aspect of this application also provides an application of the above-mentioned composite aluminum-plastic film, or a composite aluminum-plastic film prepared by the above-mentioned method, in the field of lithium-ion battery packaging.

[0062] The composite aluminum-plastic film provided in this application has excellent thermal sensitivity and exhibits corresponding heat absorption and heat dissipation properties under different temperature ranges. Its application in the field of lithium-ion battery packaging can significantly improve the thermal conductivity of lithium-ion batteries, thereby significantly improving the safety of lithium-ion batteries.

[0063] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0064] Example 1

[0065] A method for preparing a composite aluminum-plastic film, comprising:

[0066] (1) Prepare a basic layer structure, wherein the outer sealing layer 10 is a layer made by mixing and casting a thermosensitive material and a polyamide fiber. The thermosensitive material is a mixture of silicon nitride (average particle size of 35nm) and liquid crystal polyurethane elastomer (Taiwan Jih Sun, BTE-75). The polyamide fiber is nylon PA66 with a weight average molecular weight of 20,000, and the weight ratio of the thermosensitive material to PA66 is 1:3. The material of the first adhesive layer 20 is polyurethane adhesive (Dongguan Yantai Chemical Co., Ltd., TS-9015). The material of the aluminum foil layer 30 is metallic Al. The material of the second adhesive layer 40 is polypropylene adhesive (Dongguan Yantai Chemical Co., Ltd., MX-8347). The material of the heat-sealing layer 50 is polypropylene (weight average molecular weight of 3500).

[0067] (2) The outer sealing layer 10, the first adhesive layer 20, the aluminum foil layer 30, the second adhesive layer 40 and the heat sealing layer 50 are stacked in sequence and pressed together. The pressure of the pressing process is 0.32 MPa and the temperature is 55°C. After processing for 38 minutes, the stacked structure is obtained.

[0068] (3) The above-prepared laminated structure is subjected to heat treatment at a temperature of 40°C. After treatment for 4 days, it is left to stand for 2 days to obtain a composite aluminum-plastic film.

[0069] like Figure 1 As shown, the composite aluminum-plastic film prepared in this embodiment includes an outer sealing layer 10, a first adhesive layer 20, an aluminum foil layer 30, a second adhesive layer 40, and a heat-sealing layer 50 stacked sequentially. The outer sealing layer 10 has a thickness of 45 μm, the first adhesive layer 20 has a thickness of 2 μm, the aluminum foil layer 30 has a thickness of 40 μm, the second adhesive layer 40 has a thickness of 8 μm, and the heat-sealing layer 50 has a thickness of 40 μm.

[0070] Example 2

[0071] The difference from Example 1 is that the outer sealing layer 10 is made of polyamide fiber; while the heat sealing layer 50 is a layer made of heat-sensitive material and polypropylene through mixing and casting. The type of heat-sensitive material is the same as in Example 1, wherein the weight average molecular weight of polypropylene is 3500, and the weight ratio of the heat-sensitive material to polypropylene is 1:1.8; the other layers are the same as in Example 1, and the remaining preparation process is also the same as in Example 1, resulting in a composite aluminum-plastic film.

[0072] Example 3

[0073] The difference from Example 1 is that the outer sealing layer 10 is made of polyamide fiber; while the first adhesive layer 20 is a layer made by mixing and casting a heat-sensitive material and a polyurethane adhesive. The types of the heat-sensitive material and the polyurethane adhesive are the same as in Example 1, and the weight ratio of the heat-sensitive material to the polyurethane adhesive is 1:1.5. The remaining layers are the same as in Example 1, and the remaining preparation process is also the same as in Example 1, resulting in a composite aluminum-plastic film.

[0074] Example 4

[0075] A method for preparing a composite aluminum-plastic film, comprising:

[0076] (1) Prepare a basic layer structure, wherein the outer sealing layer 10 is made of polyamide fiber PA66 (weight average molecular weight is 20000), the first adhesive layer 20 is made of polyurethane adhesive (China Dongguan Yantai Chemical Co., Ltd., TS-9015), the aluminum foil layer 30 is made of metal Al, the second adhesive layer 40 is made of polypropylene adhesive (China Dongguan Yantai Chemical Co., Ltd., MX-8347), and the heat-sealing layer 50 is made of polypropylene (weight average molecular weight is 3500).

[0077] (2) A thermosensitive material was coated onto one side surface of the outer sealing layer 10 using a planar scraping method. The thermosensitive material was a mixture of silicon nitride (average particle size of 35 nm) and liquid crystal polyurethane elastomer (Taiwanese brand, BTE-75), with a weight ratio of silicon nitride to liquid crystal polyurethane elastomer of 1:5. After curing at 55°C, a coating weight of 1.8 g / cm² was obtained. 3 Functional layer 60;

[0078] (3) The outer sealing layer 10, the functional layer 60, the first adhesive layer 20, the aluminum foil layer 30, the second adhesive layer 40 and the heat sealing layer 50 are stacked in sequence and pressed together. The pressure of the pressing process is 0.32 MPa, the temperature is 55℃ and the time is 38 min to obtain the stacked structure.

[0079] (4) The above-mentioned laminated structure is subjected to heat treatment at a temperature of 40°C. After treatment for 4 days, it is left to stand for 2 days to obtain a composite aluminum-plastic film.

[0080] like Figure 2 As shown, the composite aluminum-plastic film prepared in this embodiment includes an outer sealing layer 10, a functional layer 60, a first adhesive layer 20, an aluminum foil layer 30, a second adhesive layer 40, and a heat-sealing layer 50 stacked sequentially. The outer sealing layer 10 has a thickness of 10 μm, the functional layer 60 has a thickness of 35 μm, the first adhesive layer 20 has a thickness of 2 μm, the aluminum foil layer 30 has a thickness of 40 μm, the second adhesive layer 40 has a thickness of 8 μm, and the heat-sealing layer 50 has a thickness of 40 μm. The functional layer 60 has a weight percentage of 8 wt% based on the total weight of the outer sealing layer 10, the first adhesive layer 20, the aluminum foil layer 30, the second adhesive layer 40, and the heat-sealing layer 50.

[0081] Example 5

[0082] The difference from Example 4 is that in step (2), the heat-sensitive material is a mixture of silicon nitride and aluminum nitride, wherein the average particle size of silicon nitride is 50 nm, the average particle size of aluminum nitride is 35 nm, and the weight ratio of silicon nitride to aluminum nitride is 1:1; the remaining steps are the same as in Example 4, and a composite aluminum-plastic film is obtained.

[0083] Example 6

[0084] The difference from Example 4 is that in step (2), the heat-sensitive material is a mixture of silicon nitride and aluminum nitride, wherein the average particle size of silicon nitride is 50 nm, the average particle size of aluminum nitride is 35 nm, and the weight ratio of silicon nitride to aluminum nitride is 1:10; the remaining steps are the same as in Example 4, and a composite aluminum-plastic film is obtained.

[0085] Example 7

[0086] The difference from Example 4 is that in step (2), the weight ratio of silicon nitride and liquid crystal polyurethane elastomer is 1:1; the remaining steps are the same as in Example 4, and a composite aluminum-plastic film is obtained.

[0087] Example 8

[0088] The difference from Example 4 is that in step (2), the weight ratio of silicon nitride and liquid crystal polyurethane elastomer is 1:10; the remaining steps are the same as in Example 4, and a composite aluminum-plastic film is obtained.

[0089] Example 9

[0090] The difference from Example 4 is that in step (2), the weight ratio of silicon nitride and liquid crystal polyurethane elastomer is 2:3; the remaining steps are the same as in Example 4, and a composite aluminum-plastic film is obtained.

[0091] Example 10

[0092] The difference from Example 4 is that in step (2), the thermosensitive material is a mixture of trimethyloctane and liquid crystal polyurethane elastomer, and the weight ratio of trimethyloctane to liquid crystal polyurethane elastomer is 1:0.1.

[0093] Example 11

[0094] The difference from Example 4 is that in step (2), the thermosensitive material is a mixture of trimethyloctane and liquid crystal polyurethane elastomer, and the weight ratio of trimethyloctane to liquid crystal polyurethane elastomer is 1:2.

[0095] Example 12

[0096] The difference from Example 4 is that in step (2), the thermosensitive material is a mixture of trimethyloctane and liquid crystal polyurethane elastomer, and the weight ratio of trimethyloctane to liquid crystal polyurethane elastomer is 1:3.

[0097] Example 13

[0098] The difference from Example 4 is that in step (3), the pressure of the pressing process is 0.10 MPa, the temperature is 50°C, and the time is 50 min.

[0099] Example 14

[0100] The difference from Example 4 is that in step (3), the pressure of the pressing process is 0.35 MPa, the temperature is 70°C, and the time is 25 min.

[0101] Example 15

[0102] The difference from Example 4 is that in step (3), the pressure of the pressing process is 0.40 MPa, the temperature is 40°C, and the time is 35 min.

[0103] Example 16

[0104] The difference from Example 4 is that in step (3), the pressure of the pressing process is 0.25 MPa, the temperature is 60°C, and the time is 45 min; in step (4), the temperature of the heat treatment is 40°C and the time is 10 days; the remaining steps are the same as in Example 5, and a composite aluminum-plastic film is obtained.

[0105] Example 17

[0106] The difference from Example 4 is that in step (3), the pressure of the pressing process is 0.45 MPa, the temperature is 55°C, and the time is 15 min; in step (4), the temperature of the heat treatment is 45°C and the time is 3 days; the remaining steps are the same as in Example 5, and a composite aluminum-plastic film is obtained.

[0107] Example 18

[0108] The difference from Example 4 is that in step (3), the pressure of the pressing process is 0.10 MPa and the temperature is 65°C; in step (4), the temperature of the heat treatment is 55°C; the remaining steps are the same as in Example 5, and a composite aluminum-plastic film is obtained.

[0109] Comparative Example 1

[0110] The difference from Example 1 is that the outer sealing layer 10 is made of nylon 66 with a weight average molecular weight of 20,000 by casting, that is, the outer sealing layer 10 does not contain heat-sensitive material components; the thickness of the outer sealing layer 10 is the same as the thickness of the functional layer 60 in Example 1, and the rest of the preparation process is also the same as in Example 1, to obtain an aluminum-plastic film.

[0111] Comparative Example 2

[0112] The difference from Example 2 is that the heat-sealing layer 50 is made of polypropylene with a weight average molecular weight of 3500 by casting, that is, the heat-sealing layer 50 does not contain heat-sensitive material components; the thickness of the heat-sealing layer 50 is the same as that of Example 1, and the rest of the preparation process is also the same as that of Example 1, to obtain an aluminum-plastic film.

[0113] Comparative Example 3

[0114] The difference from Example 3 is that the first adhesive layer 20 is made by casting polyurethane adhesive (Dongguan Yantai Chemical Co., Ltd., TS-9015), that is, the first adhesive layer 20 does not contain heat-sensitive material components; the thickness of the first adhesive layer 20 is the same as that of Example 1, and the rest of the preparation process is also the same as that of Example 1, to obtain aluminum-plastic film.

[0115] The average thermal conductivity of the composite aluminum-plastic films prepared in all the above embodiments and comparative examples of this application was tested at different temperature ranges using ASTM D5470. The test results are shown in Table 1.

[0116] Table 1

[0117]

[0118] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects: Compared with traditional aluminum-plastic films, the composite aluminum-plastic film provided in this application also adds a thermosensitive material or includes a functional layer 60 formed of a thermosensitive material. The addition of the thermosensitive material or the setting of the functional layer 60 can improve the thermosensitive performance of the composite aluminum-plastic film, so that the soft-pack battery has a stronger heat absorption capacity in the first temperature range of 50 to 120°C and a stronger heat dissipation capacity in the second temperature range above 120°C. That is, by adjusting the balance between heat absorption and heat dissipation of the functional layer 60 in different temperature ranges, the thermal conductivity of the soft-pack battery under different temperature environments is improved, thereby significantly improving the safety of the soft-pack battery.

[0119] Compared to other ranges, limiting the difference between the average thermal conductivity of the first temperature range and the average thermal conductivity of the second temperature range to the above range (i.e., strictly controlling the value range of (k2-k1) / k1 within the above range) is beneficial to improving the thermal conductivity of the pouch battery under different temperature environments, thereby improving the safety of the pouch battery.

[0120] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0121] The above description is merely a preferred 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 principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite aluminum-plastic film, characterized in that, The composite aluminum-plastic film includes a basic layer structure, which includes an outer sealing layer (10), a first adhesive layer (20), an aluminum foil layer (30), a second adhesive layer (40), and a heat-sealing layer (50) stacked sequentially. In the basic layer structure, one or more layers other than the aluminum foil layer (30) contain a heat-sensitive material. Alternatively, the composite aluminum-plastic film may also include at least one functional layer (60) formed of the heat-sensitive material, and each functional layer (60) is located on the surface of the basic layer structure or between any two layers. The thermosensitive material is a mixture of inorganic and organic thermosensitive materials, and the thermosensitive material is a mixture of silicon nitride and liquid crystal polyurethane elastomer in a weight ratio of 1:(1-10); or, the thermosensitive material is a mixture of silicon carbide and liquid crystal acrylate elastomer in a weight ratio of 1:(1-10); or, The thermosensitive material is an inorganic thermosensitive material, and the thermosensitive material is a mixture of silicon carbide and aluminum silicate in a weight ratio of 1:(1-15); or, The thermosensitive material is an organic thermosensitive material, and the thermosensitive material is C4-C4 with a weight ratio of 1:(0.1-2). 20 A mixture of aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomers; or, the thermosensitive material is a C6-C4 mixture with a weight ratio of 1:(0.1-2). 12 A mixture of fatty acid compounds and liquid crystal polyurethane elastomers; The composite aluminum-plastic film has an average thermal conductivity of k1 in the first temperature range and an average thermal conductivity of k2 in the second temperature range. k1 is 0.15 to 0.45 W / (m·k) and (k2-k1) / k1 ≥ 30%. The temperature in the first temperature range is 50 to 120°C, and the temperature in the second temperature range is higher than 120°C.

2. The composite Al-plastic film according to claim 1, characterized in that, The composite aluminum-plastic film further includes at least one of the functional layers (60), wherein the functional layer (60) comprises 0.5–15 wt% of the total weight of the basic layer structure; and / or, The thickness of the functional layer (60) is 10-50 μm.

3. The composite aluminum-plastic film according to claim 1, characterized in that, The outer sealing layer (10) is a composite layer of the thermosensitive material and polyamide fiber, wherein the weight ratio of the thermosensitive material to the polyamide fiber is 1:(1-10); and / or, The heat-sealing layer (50) is a composite layer of the thermosensitive material and the polyolefin, wherein the weight ratio of the thermosensitive material to the polyolefin is 1:(0.5-2); and / or, The first adhesive layer (20) is a composite layer of the heat-sensitive material and the polyurethane adhesive, wherein the weight ratio of the heat-sensitive material to the polyurethane adhesive is 1:(1-10); and / or, The second adhesive layer (40) is a composite layer of the heat-sensitive material and the polyolefin adhesive, and the weight ratio of the heat-sensitive material to the polyolefin adhesive is 1:(1~10).

4. The composite Al-plastic film according to claim 1, wherein The outer sealing layer (10) has a thickness of 8-50 μm, the first adhesive layer (20) has a thickness of 2-10 μm, the aluminum foil layer (30) has a thickness of 10-100 μm, the second adhesive layer (40) has a thickness of 3-15 μm, the heat-sealing layer (50) has a thickness of 15-80 μm, and the functional layer has a thickness of 10-50 μm; or, the outer sealing layer (10) has a thickness of 8-100 μm, the first adhesive layer (20) has a thickness of 2-60 μm, the aluminum foil layer (30) has a thickness of 10-100 μm, the second adhesive layer (40) has a thickness of 3-65 μm, and the heat-sealing layer (50) has a thickness of 15-130 μm.

5. A method for producing the composite aluminum laminate film according to any one of claims 1 to 4, characterized by, The method for preparing the composite aluminum-plastic film includes: Step S1: Prepare each layer in the basic layer structure; Step S2: When preparing one or more optional layers other than the aluminum foil layer (30) in the basic layer structure, a thermosensitive material is added; or, the thermosensitive material is coated on the surface of the basic layer structure or between any two optional layers, and a laminated structure is obtained after pressing. The thermosensitive material is selected from inorganic thermosensitive materials and / or organic thermosensitive materials; and the thermosensitive material has the same definition as in claim 1. Step S3: Perform heat treatment on the laminated structure to obtain the composite aluminum-plastic film.

6. The method for preparing the composite aluminum-plastic film according to claim 5, characterized in that, The pressing process is carried out at a pressure of 0.10–0.45 MPa, a temperature of 50–70 °C, and a time of 5–45 min; and / or, The heat treatment is performed at a temperature of 30–50°C for 3–10 days.

7. The method for preparing the composite aluminum-plastic film according to claim 5, characterized in that, The average particle size of the inorganic thermosensitive material is 10–50 nm.

8. The method for preparing the composite aluminum-plastic film according to claim 5, characterized in that, The heat-sensitive material is added when preparing one or more optional layers other than the aluminum foil layer (30) in the basic layer structure. The outer sealing layer (10) is a composite layer made by mixing and casting the heat-sensitive material and polyamide fiber; and / or, the heat-sealing layer (50) is a composite layer made by mixing and casting the heat-sensitive material and polyolefin; and / or, the first adhesive layer (20) is a composite layer made by mixing and casting the heat-sensitive material and polyurethane adhesive; and the second adhesive layer (40) is a composite layer made by mixing and casting the heat-sensitive material and polyolefin adhesive.

9. The method for preparing the composite aluminum-plastic film according to claim 5, characterized in that, When the thermosensitive material is a mixture of silicon nitride and liquid crystal polyurethane elastomer, the pressure of the pressing process is 0.25–0.45 MPa, the temperature is 55–60°C, and the time is 15–45 min; the temperature of the heat treatment is 40–45°C, and the time is 3–10 days; and / or, the thermosensitive material is C4–C 20 When the mixture of aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomer is used, the pressure of the pressing process is 0.15-0.35 MPa, the temperature is 40-60°C, and the time is 5-35 min; the temperature of the heat treatment is 40-45°C, and the time is 3-8 days.

10. The method for preparing the composite aluminum-plastic film according to claim 5, characterized in that, When the thermosensitive material is coated onto the surface of the base layer structure or optionally between two layers, and the thermosensitive material is a mixture of silicon nitride and liquid crystal polyurethane elastomer, the pressing process is performed at a pressure of 0.35–0.40 MPa, a temperature of 55–60°C, and a time of 30–45 min; the heat treatment is performed at a temperature of 40–45°C and a time of 5–7 days; and / or, The thermosensitive material is C4~C 20 When the mixture of aliphatic hydrocarbon compounds and liquid crystal polyurethane elastomer is used, the pressure of the pressing process is 0.15-0.20 MPa, the temperature is 40-50°C, and the time is 10-25 min; the temperature of the heat treatment is 40-45°C, and the time is 3-8 days.

11. The method for preparing the composite aluminum-plastic film according to claim 5, characterized in that, The heat treatment process is followed by a settling process.

12. The method for preparing the composite aluminum-plastic film according to claim 11, characterized in that, The settling process is carried out at a temperature of 20–25°C for 1–7 days.

13. The application of a composite aluminum-plastic film according to any one of claims 1 to 4, or a composite aluminum-plastic film prepared by the method of any one of claims 5 to 12, in the field of lithium-ion battery packaging.

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