A lithium battery case material and a method for manufacturing the same

Abstract

This invention relates to a lithium battery casing material and its preparation method, belonging to the field of materials technology. By weight, the lithium battery casing material comprises 95-105 parts of a matrix resin, 10-15 parts of a modified thermally conductive filler, and 2-5 parts of additives. The modified thermally conductive filler includes a thermally conductive filler and a coating layer located on at least a portion of the surface of the thermally conductive filler. Based on existing matrix resin systems, this invention mainly modifies the surface of the thermally conductive filler by using at least two different fatty alcohol polyoxyethylene ethers containing specific numbers of polyoxyethylene chain units and a silane coupling agent. This not only achieves effective filling of a high proportion of thermally conductive filler but also significantly improves the mechanical properties and thermal conductivity of the lithium battery casing material while ensuring its leak-proof sealing, thereby improving the safety and reliability of lithium battery use.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and in particular to a lithium battery casing material and its preparation method. Background Technology

[0002] Lithium-ion batteries, as key devices in modern energy storage and conversion, are widely used in electric vehicles, portable electronic devices, energy storage systems, and many other fields. The battery casing, a crucial component, not only protects the internal cells, prevents electrolyte leakage, and avoids adverse effects from external environmental factors on battery performance, but also performs important functions such as heat dissipation and structural support. Its performance directly affects the safety, reliability, and lifespan of the lithium-ion battery. Therefore, developing high-performance lithium-ion battery casing materials is of paramount importance for promoting the development and application of lithium-ion battery technology.

[0003] Currently, the selection of materials for lithium battery casings mainly falls into two categories: metals and plastics. Metals include aluminum alloys and stainless steel, while plastics include polypropylene and polycarbonate. Among them, polypropylene and other plastic materials have become a research hotspot in the field of lithium battery casings in recent years due to their significant advantages such as low cost and light weight. However, existing lithium battery casing materials such as polypropylene have significant shortcomings in terms of mechanical strength and thermal conductivity. These defects weaken the safety and reliability of lithium batteries to some extent, thus limiting their wider application prospects. Summary of the Invention

[0004] To address the above problems, this invention provides a lithium battery casing material and its preparation method.

[0005] In a first aspect, the present invention provides a lithium battery casing material, wherein, by weight parts, the lithium battery casing material comprises:

[0006] 95-105 parts of matrix resin, 10-15 parts of modified thermally conductive filler, and 2-5 parts of additives;

[0007] The modified thermally conductive filler includes a thermally conductive filler and a coating layer located on at least a portion of the surface of the thermally conductive filler, wherein the raw material of the coating layer includes:

[0008] Silane coupling agents; and

[0009] At least one of the general formulas is R1-O-(CH2CH2O). x H's first fatty alcohol polyoxyethylene ether; and

[0010] At least one of the general formulas is R2-O-(CH2CH2O). y H's second fatty alcohol polyoxyethylene ether;

[0011] Wherein, R1 and R2 are each independently an alkyl group, x is any natural number selected from 3 to 5, and y is any natural number selected from 10 to 15.

[0012] Furthermore, the lithium battery casing material includes:

[0013] The matrix resin consists of 100 parts, the modified thermally conductive filler consists of 13 parts, and the additives consists of 3.5 parts.

[0014] Furthermore, the weight ratio of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether, and the second fatty alcohol polyoxyethylene ether is 100:(1~3):(0.5~1):(0.5~1).

[0015] Furthermore, the thermally conductive filler includes at least one selected from aluminum oxide, magnesium oxide, zinc oxide, aluminum nitride, and boron nitride;

[0016] And / or, the silane coupling agent comprises at least one of 3-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane;

[0017] And / or, the first fatty alcohol polyoxyethylene ether includes at least one of fatty alcohol polyoxyethylene ether-3, fatty alcohol polyoxyethylene ether-4, and fatty alcohol polyoxyethylene ether-5;

[0018] And / or, the second fatty alcohol polyoxyethylene ether includes at least one of fatty alcohol polyoxyethylene ether-10, fatty alcohol polyoxyethylene ether-11, fatty alcohol polyoxyethylene ether-12, fatty alcohol polyoxyethylene ether-13, fatty alcohol polyoxyethylene ether-14, and fatty alcohol polyoxyethylene ether-15.

[0019] Furthermore, the matrix resin is composed of polypropylene, hydrogenated styrene-butadiene-styrene block copolymer and polyethylene in a weight ratio of (5~8):(1~2):(1~2).

[0020] Furthermore, the additives include at least one of antioxidants, lubricants, and compatibilizers.

[0021] Secondly, based on the same inventive concept, the present invention provides a method for preparing the lithium battery casing material as described in any one of the first aspects above, the method for preparing the lithium battery casing material comprising the following steps:

[0022] Thermally conductive filler, silane coupling agent, first fatty alcohol polyoxyethylene ether and second fatty alcohol polyoxyethylene ether are added to an alcohol-water solution and heated and stirred, then filtered, dried and ground to obtain the modified thermally conductive filler.

[0023] The modified thermally conductive filler, matrix resin, and additives are melt-extruded to obtain the lithium battery casing material.

[0024] Furthermore, the pH of the alcohol-water solution is 4.5 to 5.5, and the weight ratio of the thermally conductive filler to the alcohol-water solution is 1:(4 to 8).

[0025] Furthermore, the working conditions parameters for heating and stirring include: stirring speed of 500~600 rpm, stirring time of 1~2 h, and stirring temperature of 60~75℃;

[0026] And / or, the working conditions parameters for the grinding include: a grinding speed of 50~100 rpm and a grinding time of 20~40 min.

[0027] Further, the modified thermally conductive filler, matrix resin, and additives are added to a twin-screw extruder for melt extrusion to obtain the lithium battery casing material; wherein, the operating parameters of the twin-screw extruder include: screw diameter of 15~25mm, screw length-to-diameter ratio of (35~45):1, temperature settings as follows: first stage 168~172℃, second stage 178~182℃, third stage 188~192℃, fourth stage 198~202℃, fifth stage 208~212℃, melt temperature 204~206℃, and die head temperature 210~215℃.

[0028] The technical solutions provided in the embodiments of the present invention have at least the following advantages compared with the prior art:

[0029] This invention provides a lithium battery casing material. Based on existing matrix resin systems, this invention mainly modifies the surface of the thermally conductive filler by using at least two different fatty alcohol polyoxyethylene ethers containing specific numbers of polyoxyethylene chain units and a silane coupling agent. One end of the silane coupling agent molecule can chemically bond with the metal oxide on the surface of the thermally conductive filler, while the other end can physically or chemically interact with the resin matrix, acting as a "bridge" to enhance interfacial bonding. The first fatty alcohol polyoxyethylene ether with 3-5 polyoxyethylene chain units and the second fatty alcohol polyoxyethylene ether with 10-15 polyoxyethylene chain units are used in combination to effectively suppress physical entanglement between long molecular chains, reduce the surface energy of the thermally conductive filler, and prevent its agglomeration. The synergistic effect of these three components enables the thermally conductive filler to achieve high filling, high dispersion, and high-strength interfacial bonding in the matrix resin. This significantly improves the mechanical properties and thermal conductivity of the lithium battery casing material while ensuring its leak-proof sealing, thereby enhancing the safety and reliability of lithium battery use. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention can be purchased commercially or prepared using existing methods. Furthermore, unless otherwise specified or detailed, the steps and parameters involved in this invention can be performed according to existing preparation processes or directly using existing equipment; these will not be elaborated upon further in this document.

[0032] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0033] Example 1

[0034] This example provides a lithium battery casing material, which, by weight, comprises:

[0035] The matrix resin consists of 100 parts, the modified thermally conductive filler consists of 13 parts, and the additives consists of 3.5 parts.

[0036] The matrix resin is composed of polypropylene (specific product model R200P), hydrogenated styrene-butadiene-styrene block copolymer (specific product model G7720 GI-N) and polyethylene (specific product model 2200J) in a weight ratio of 7:1:1.5.

[0037] The modified thermally conductive filler includes a thermally conductive filler (specifically alumina powder) and a coating layer located on the thermally conductive filler. The raw materials of the coating layer include a silane coupling agent (specifically γ-glycidyl etheroxypropyltrimethoxysilane), a first fatty alcohol polyoxyethylene ether (specifically fatty alcohol polyoxyethylene ether-4, AEO-4), and a second fatty alcohol polyoxyethylene ether (specifically fatty alcohol polyoxyethylene ether-12, AEO-12). The weight ratio of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether, and the second fatty alcohol polyoxyethylene ether is 100:2:0.7:0.7 (the specific weights of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether, and the second fatty alcohol polyoxyethylene ether are 100g, 2g, 0.7g, and 0.7g, respectively).

[0038] The additive is composed of an antioxidant (specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, antioxidant 1010) and a lubricant (specifically calcium stearate) in a weight ratio of 1:0.5.

[0039] The preparation method of the above-mentioned lithium battery casing material includes the following steps:

[0040] Thermally conductive filler, silane coupling agent, first fatty alcohol polyoxyethylene ether, and second fatty alcohol polyoxyethylene ether were added to an alcohol-water solution (prepared by mixing water and ethanol in a volume ratio of 1:1, and then adjusting the pH to 5.0 with an appropriate amount of glacial acetic acid; the weight of the alcohol-water solution added was 5 times that of the thermally conductive filler). The mixture was heated and stirred at 65°C and 560 rpm for 1.5 h, then washed with anhydrous ethanol, filtered, and dried. The resulting solid was ground at 80 rpm for 30 min to obtain the modified thermally conductive filler.

[0041] The modified thermally conductive filler, matrix resin, and additives are mixed and then added to a twin-screw extruder for melt extrusion to obtain the lithium battery casing material. The operating parameters of the twin-screw extruder include: screw diameter of 20 mm, screw length-to-diameter ratio of 40:1, temperature settings of: 170°C for the first stage, 180°C for the second stage, 190°C for the third stage, 200°C for the fourth stage, and 210°C for the fifth stage, melt temperature of 205°C, and die head temperature of 212°C.

[0042] Example 2

[0043] This example provides a lithium battery casing material, which, by weight, comprises:

[0044] 95 parts of matrix resin, 10 parts of modified thermally conductive filler and 2 parts of additives;

[0045] The matrix resin is composed of polypropylene (specific product model R200P), hydrogenated styrene-butadiene-styrene block copolymer (specific product model G7720 GI-N), and polyethylene (specific product model 2200J) in a weight ratio of 5:1:2.

[0046] The modified thermally conductive filler includes a thermally conductive filler (specifically alumina powder) and a coating layer located on the thermally conductive filler. The raw materials of the coating layer include a silane coupling agent (specifically 3-aminopropyltriethoxysilane), a first fatty alcohol polyoxyethylene ether (specifically fatty alcohol polyoxyethylene ether-3, AEO-3), and a second fatty alcohol polyoxyethylene ether (specifically fatty alcohol polyoxyethylene ether-10, AEO-10). The weight ratio of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether, and the second fatty alcohol polyoxyethylene ether is 100:1:0.5:0.5 (the specific weights of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether, and the second fatty alcohol polyoxyethylene ether are 100g, 1g, 0.5g, and 0.5g, respectively).

[0047] The additive is composed of an antioxidant (specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, antioxidant 1010) and a lubricant (specifically calcium stearate) in a weight ratio of 1:0.5.

[0048] The preparation method of the above-mentioned lithium battery casing material includes the following steps:

[0049] Thermally conductive filler, silane coupling agent, first fatty alcohol polyoxyethylene ether, and second fatty alcohol polyoxyethylene ether were added to an alcohol-water solution (prepared by mixing water and ethanol in a volume ratio of 1:1, and then adjusting the pH to 4.5 with an appropriate amount of glacial acetic acid; the weight of the alcohol-water solution added was 4 times that of the thermally conductive filler). The mixture was heated and stirred at 60°C and 500 rpm for 2 hours. The mixture was then washed with anhydrous ethanol, filtered, and dried. The resulting solid was ground at 80 rpm for 30 minutes to obtain the modified thermally conductive filler.

[0050] The modified thermally conductive filler, matrix resin, and additives are mixed and then added to a twin-screw extruder for melt extrusion to obtain the lithium battery casing material. The operating parameters of the twin-screw extruder include: screw diameter of 20 mm, screw length-to-diameter ratio of 40:1, temperature settings of: 170°C for the first stage, 180°C for the second stage, 190°C for the third stage, 200°C for the fourth stage, and 210°C for the fifth stage, melt temperature of 205°C, and die head temperature of 212°C.

[0051] Example 3

[0052] This example provides a lithium battery casing material, which, by weight, comprises:

[0053] 105 parts of matrix resin, 15 parts of modified thermally conductive filler, and 5 parts of additives;

[0054] The matrix resin is composed of polypropylene (specific product model R200P), hydrogenated styrene-butadiene-styrene block copolymer (specific product model G7720 GI-N), and polyethylene (specific product model 2200J) in a weight ratio of 8:2:1.

[0055] The modified thermally conductive filler includes a thermally conductive filler (specifically alumina powder) and a coating layer located on the thermally conductive filler. The raw materials of the coating layer include a silane coupling agent (specifically 3-aminopropyltriethoxysilane), a first fatty alcohol polyoxyethylene ether (specifically fatty alcohol polyoxyethylene ether-5, AEO-5), and a second fatty alcohol polyoxyethylene ether (specifically fatty alcohol polyoxyethylene ether-15, AEO-15). The weight ratio of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether, and the second fatty alcohol polyoxyethylene ether is 100:3:1:1 (the specific weights of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether, and the second fatty alcohol polyoxyethylene ether are 100g, 3g, 1g, and 1g, respectively).

[0056] The additive is composed of an antioxidant (specifically pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, antioxidant 1010), a lubricant (specifically calcium stearate), and a compatibilizer (specifically maleic anhydride-grafted polypropylene) in a weight ratio of 1:0.5:1.

[0057] The preparation method of the above-mentioned lithium battery casing material includes the following steps:

[0058] Thermally conductive filler, silane coupling agent, first fatty alcohol polyoxyethylene ether, and second fatty alcohol polyoxyethylene ether were added to an alcohol-water solution (prepared by mixing water and ethanol in a volume ratio of 1:1, and then adjusting the pH to 5.5 with an appropriate amount of glacial acetic acid; the weight of the alcohol-water solution added was 8 times that of the thermally conductive filler). The mixture was heated and stirred at 75°C and 600 rpm for 1 hour, then washed with anhydrous ethanol, filtered, and dried. The resulting solid was ground at 80 rpm for 30 minutes to obtain the modified thermally conductive filler.

[0059] The modified thermally conductive filler, matrix resin, and additives are mixed and then added to a twin-screw extruder for melt extrusion to obtain the lithium battery casing material. The operating parameters of the twin-screw extruder include: screw diameter of 20 mm, screw length-to-diameter ratio of 40:1, temperature settings of: 170°C for the first stage, 180°C for the second stage, 190°C for the third stage, 200°C for the fourth stage, and 210°C for the fifth stage, melt temperature of 205°C, and die head temperature of 212°C.

[0060] Example 4

[0061] This example provides a lithium battery casing material and its preparation method, which differs from Example 1 only in that:

[0062] (1) The weight ratio of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether and the second fatty alcohol polyoxyethylene ether is 100:5:3:3 (that is, the specific weights of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether and the second fatty alcohol polyoxyethylene ether are 100g, 5g, 3g and 3g respectively).

[0063] Comparative Example 1

[0064] This example provides a lithium battery casing material and its preparation method, which differs from Example 1 only in that:

[0065] (1) The modified thermally conductive filler was not subjected to surface coating modification treatment; that is, the alumina powder raw material in Example 1 was ground at 80 rpm for 30 min to obtain the modified thermally conductive filler.

[0066] Comparative Example 2

[0067] This example provides a lithium battery casing material and its preparation method, which differs from Example 1 only in that:

[0068] (1) No first fatty alcohol polyoxyethylene ether (i.e., no fatty alcohol polyoxyethylene ether-4, AEO-4) was added.

[0069] Comparative Example 3

[0070] This example provides a lithium battery casing material and its preparation method, which differs from Example 1 only in that:

[0071] (1) No second fatty alcohol polyoxyethylene ether (i.e., no fatty alcohol polyoxyethylene ether-12, AEO-12) was added.

[0072] Test Example 1

[0073] This example demonstrates the performance testing of the lithium battery casing materials obtained in Examples 1-4 and Comparative Examples 1-3. The testing methods are as follows:

[0074] Leakage and sealing performance test: The lithium battery shell materials obtained in Examples 1-3 and Comparative Examples 1-4 were used to injection mold a box with a length, width and height of 0.3m x 0.3m x 0.1m and a pipe interface on one side wall; the box was filled with electrolyte through the pipe interface and a pressure of 0.3MPa was applied and maintained for 24h. The side wall of the box was then observed to see if there was any liquid leakage.

[0075] Thermal conductivity test: The lithium battery shell materials obtained in Examples 1-3 and Comparative Examples 1-4 were injection molded into film samples of the same size on one side and placed in the middle of a heat source with a fixed temperature of 80°C at one end and a temperature sensing probe at the other end. The test was conducted for 20 seconds, and the temperature rise data was recorded. The temperature rise value ΔT was calculated according to Formula 1. Wherein, Formula 1: ΔT=T2-T1, T1 is the temperature before the start of the test (time is 0s), T2 is the temperature after the start of the test (time is 15s), and the larger ΔT is, the better the thermal conductivity.

[0076] The test results are shown in Table 1.

[0077] Table 1

[0078]

[0079] As shown in Table 1:

[0080] 1) Compared with comparative examples 1 to 3, the lithium battery casing materials provided in Examples 1 to 4 of this application achieve effective filling of high proportion of thermally conductive filler by using at least two different fatty alcohol polyoxyethylene ethers containing specific polyoxyethylene chain units and silane coupling agents to coat and modify the surface of the thermally conductive filler. Moreover, the materials have good anti-seepage sealing performance and significantly improve the thermal conductivity of the lithium battery casing material.

[0081] 2) The thermal conductivity test results of Examples 1 and 4 show that when the amount of modified thermally conductive filler such as fatty alcohol polyoxyethylene ether and silane coupling agent is too large, it will lead to an excessively thick coating layer, thereby reducing the thermal conductivity of the lithium battery shell material to a certain extent.

[0082] Test Example 2

[0083] In this example, the tensile strength of the lithium battery casing materials obtained in Examples 1-3 above was further tested in accordance with ASTM D638 standard, and the test results are shown in Table 2.

[0084] Table 2

[0085]

[0086] As shown in Table 2, the tensile strength of the lithium battery casing material provided in the embodiments of the present invention is maintained at 87~106 MPa, and the tensile strength of Embodiment 1 is the highest, reaching 106 MPa, which can meet the requirements for use of lithium battery casing materials (>60 MPa).

[0087] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0088] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A lithium battery case material, characterized by, The lithium battery casing material comprises, by weight parts: 95-105 parts of matrix resin, 10-15 parts of modified thermally conductive filler, and 2-5 parts of additives; The modified thermally conductive filler includes a thermally conductive filler and a coating layer located on at least a portion of the surface of the thermally conductive filler, wherein the raw material of the coating layer includes: Silane coupling agents; and at least one fatty alcohol polyoxyethylene ether of the general formula R1-O-(CH2CH2O) x a first fatty alcohol polyoxyethylene ether of the general formula R1-O-(CH2CH2O) at least one fatty alcohol polyoxyethylene ether of the general formula R2-O-(CH2CH2O) y a second fatty alcohol polyoxyethylene ether of H; Wherein, R1 and R2 are each independently an alkyl group, x is any natural number selected from 3 to 5, and y is any natural number selected from 10 to 15; The weight ratio of the thermally conductive filler, the silane coupling agent, the first fatty alcohol polyoxyethylene ether, and the second fatty alcohol polyoxyethylene ether is 100:(1~3):(0.5~1):(0.5~1). The matrix resin is composed of polypropylene, hydrogenated styrene-butadiene-styrene block copolymer and polyethylene in a weight ratio of (5~8):(1~2):(1~2).

2. The lithium battery enclosure material of claim 1, wherein, include: The matrix resin consists of 100 parts, the modified thermally conductive filler consists of 13 parts, and the additives consists of 3.5 parts.

3. The lithium battery enclosure material of claim 1, wherein, The thermally conductive filler includes at least one of aluminum oxide, magnesium oxide, zinc oxide, aluminum nitride, and boron nitride; And / or, the silane coupling agent comprises at least one of 3-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane.

4. The lithium battery enclosure material of claim 1, wherein, The additives include at least one of antioxidants, lubricants, and compatibilizers.

5. A method of producing the lithium battery case material according to any one of claims 1 to 4, characterized by, The method for preparing the lithium battery casing material includes the following steps: Thermally conductive filler, silane coupling agent, first fatty alcohol polyoxyethylene ether and second fatty alcohol polyoxyethylene ether are added to an alcohol-water solution and heated and stirred. Then, the mixture is filtered, dried and ground to obtain the modified thermally conductive filler. The modified thermally conductive filler, matrix resin, and additives are melt-extruded to obtain the lithium battery casing material.

6. The method for preparing the lithium battery casing material according to claim 5, characterized in that, The pH of the alcohol-water solution is 4.5-5.5, and the weight ratio of the thermally conductive filler to the alcohol-water solution is 1:(4-8).

7. The method for preparing the lithium battery casing material according to claim 5, characterized in that, The working conditions parameters for heating and stirring include: stirring speed of 500~600 rpm, stirring time of 1~2 h, and stirring temperature of 60~75℃. And / or, the working conditions parameters for the grinding include: a grinding speed of 50~100 rpm and a grinding time of 20~40 min.

8. The method for preparing the lithium battery casing material according to claim 5, characterized in that, The modified thermally conductive filler, matrix resin, and additives are added to a twin-screw extruder for melt extrusion to obtain the lithium battery casing material. The operating parameters of the twin-screw extruder include: screw diameter of 15~25mm, screw length-to-diameter ratio of (35~45):1, temperature settings as follows: first stage 168~172℃, second stage 178~182℃, third stage 188~192℃, fourth stage 198~202℃, fifth stage 208~212℃, melt temperature 204~206℃, and die head temperature 210~215℃.

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