High-safety weight-reducing packaging material for double-high device, preparation method of high-safety weight-reducing packaging material and battery

Abstract

The invention provides a high-safety weight-reducing packaging material for a double-high device, a preparation method of the high-safety weight-reducing packaging material and a battery. The packaging material comprises a sandwich type layered composite structure composed of a modified aluminum foil layer, an activated carbon fiber layer and a modified aluminum foil layer. Wherein the activated carbon fiber layer is located between the upper modified aluminum foil layer and the lower modified aluminum foil layer, the face, in direct contact with the activated carbon fiber layer, of each modified aluminum foil layer is of a micro-nano hole structure, and silicon is deposited in a hole channel of each micro-nano hole structure; and hydrophilic active groups are arranged on the surface of the activated carbon fiber layer. According to the prepared packaging material, the light weight of the packaging material is achieved, the high temperature resistance, the aging resistance and the structural strength performance of the packaging material are improved, and reliable guarantee is provided for stable operation of equipment of the type.

Description

Technical Field

[0001] This invention specifically relates to a high-safety, weight-reducing packaging material for dual-high-performance devices, its preparation method, and a battery. Background Technology

[0002] As the new energy industry extends to high-power applications, the demand for high-energy and high-power "dual-high" energy storage devices is rapidly increasing for high-power equipment such as laser power supplies and peak-shaving / frequency-modulating power supplies. These devices not only require energy storage devices with high energy density to support continuous operation, but also need to meet stringent operating conditions such as instantaneous high-power output and frequent charge-discharge cycles. Packaging materials, as the outer protective layer and structural framework of energy storage devices, directly determine the operational stability, volume integration, and safety reliability of the equipment. Currently, packaging materials for energy storage devices suitable for high-power equipment have three main performance requirements: First, lightweight design. Laser power supplies are often used in precision machining and mobile detection scenarios, where the equipment is highly sensitive to size and weight. Excessively heavy packaging materials limit the portability and installation flexibility of the equipment. Peak-shaving / frequency-modulating power supplies often require multi-module stacking deployment. Lightweight packaging materials can reduce the load on the overall equipment's supporting structure and reduce its footprint. Traditional metal packaging materials, due to their high density, have become a key factor restricting the miniaturization and integration of such high-power equipment. Second, high safety. During instantaneous high-power output, dual-high power supplies are prone to generating localized high temperatures inside the energy storage devices, and these temperatures can persist for extended periods at high frequencies. Start-up and shutdown will exacerbate stress fluctuations at the material interface. Peak-shaving and frequency-modulated power supplies need to continuously switch charging and discharging states when the grid load fluctuates. Under long-term dynamic operating conditions, the packaging materials must withstand aging and corrosion in complex environments to avoid electrolyte leakage due to interface delamination and structural damage, which could lead to equipment failure or even safety accidents. Thirdly, high structural strength is required. Laser power supply operation may be accompanied by equipment vibration and instantaneous impact. The packaging materials must have sufficient impact resistance to protect the internal battery cells. In the scenario of multi-module stacking of peak-shaving and frequency-modulated power supplies, the packaging materials must withstand the pressure of the upper module and resist structural fatigue during long-term use to prevent short circuits or performance degradation of the battery cells due to deformation.

[0003] From the perspective of existing technology, current packaging materials for high-power equipment still face significant technical bottlenecks and cannot meet the aforementioned comprehensive requirements. Pure metal packaging materials have obvious limitations. While mainstream pure aluminum foil packaging offers a certain degree of sealing and corrosion resistance, its high density is unfavorable for the lightweight design of high-power equipment. Furthermore, its structural strength is limited, making it prone to deformation or damage under the instantaneous impact of laser power supplies or the long-term stacking pressure of peak-modulated and frequency-modulated power supplies, failing to provide stable structural support. On the other hand, while stainless steel foil offers higher strength, its density is even greater, and its welding process is complex, making it difficult to meet the packaging flexibility requirements of high-power equipment. Traditional polymer composite packaging materials have safety defects. In pursuit of lightweighting, the industry has tried to use metal composite structures. Although these materials have some optimization in terms of weight, polymer materials have poor high temperature resistance. Under the local high temperature environment generated by the instantaneous high power operation of the laser power supply, they are prone to melting and aging. In addition, the interfacial bonding stability between polymer and metal foil is insufficient. During the frequent charge and discharge cycles of peak-modulated and frequency-modulated power supplies, interfacial delamination is likely to occur, leading to packaging protection failure and increasing the risk of equipment failure. Furthermore, the structural strength of these materials is weak and cannot withstand the vibration impact and stacking pressure of high-power equipment. Additional support components are required, which negates the advantages of lightweighting.

[0004] Aluminum / carbon fiber composite technology is an ideal choice for balancing lightweight and strength. However, due to the significant differences in surface properties between the two materials, there is a serious "non-wetting" problem. Traditional processing methods struggle to form a stable interfacial bond. Some solutions only involve simple mechanical polishing of the carbon fiber surface, resulting in weak interfacial bonding. Under the high-frequency vibration or cyclic conditions of high-power equipment, delamination is highly likely to occur. Another solution modifies the aluminum surface with chemical reagents, but without optimizing the microstructure of the aluminum surface, the interfacial bonding stability is insufficient, making it susceptible to environmental corrosion and performance degradation during long-term use. Still other solutions can improve the roughness of the aluminum surface, but without targeted activation of the carbon fiber. Furthermore, the corrosion resistance of the modified material is insufficient to meet the long-term operating requirements of laser power supplies and peak-shaving / frequency-modulating power supplies, making it unsuitable for the harsh operating conditions of such high-power equipment.

[0005] Currently, no existing technology can simultaneously meet the comprehensive requirements of lightweight, high safety, and high strength for packaging materials of such high-energy, high-power energy storage devices, leaving a technological gap to be filled. Therefore, developing a packaging material that can solve the aluminum / carbon fiber impregnation problem and is compatible with the needs of high-energy, high-power devices such as laser power supplies and peak-shaving / frequency-modulating power supplies is crucial for promoting the industrial application of high-energy, high-power energy storage devices in these scenarios. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a high-safety, weight-reducing packaging material for dual-high-performance devices, its preparation method, and a battery. This invention utilizes a synergistic technical solution involving carbon fiber surface activation, aluminum surface microstructure optimization, and silicon interface composite modification to construct a stable interfacial bonding mechanism. This achieves both lightweight packaging material and improved high-temperature resistance, aging resistance, and structural strength. It is effectively adapted to the operating conditions of dual-high-performance energy storage devices used in laser power supplies and peak-shaving / frequency-modulation applications, filling a gap in existing technologies and providing reliable assurance for the stable operation of such devices.

[0007] The present invention solves the above-mentioned technical problems through the following technical solutions:

[0008] This invention provides a high-safety, weight-reducing packaging material for dual-high-performance devices, comprising a sandwich-like layered composite structure of a modified aluminum foil layer, an activated carbon fiber layer, and a modified aluminum foil layer.

[0009] The activated carbon fiber layer is located between the upper and lower modified aluminum foil layers. The side of the modified aluminum foil layer that is in direct contact with the activated carbon fiber layer has a micro-nano pore structure, and silicon is deposited in the pores of the micro-nano pore structure.

[0010] The surface of the activated carbon fiber layer has hydrophilic active groups.

[0011] In this invention, the "dual-high device" generally refers to a high-energy, high-power energy storage device, such as a high-power lithium-ion battery, a supercapacitor, or a hybrid energy storage device.

[0012] In this invention, the overall thickness of the encapsulation material is preferably 0.8-1.2 mm, for example 0.9 mm, 1 mm, or 1.1 mm; the sum of the thicknesses of the modified aluminum foil layers accounts for 18-22% of the total thickness of the encapsulation material, for example 19%, 20%, or 21%; the thickness of a single modified aluminum foil layer can be the same or different depending on the applicable situation, as long as the sum of the thicknesses of the upper and lower modified aluminum foil layers is within the corresponding range; the activated carbon fiber layer accounts for 78-82% of the total thickness of the encapsulation material, for example 79%, 80%, or 81%.

[0013] In one specific embodiment, the overall thickness of the encapsulation material is 1 mm, the activated carbon fiber layer accounts for 80% of the total thickness of the encapsulation material, and the thickness of a single modified aluminum foil layer accounts for 10% of the total thickness of the encapsulation material.

[0014] In this invention, the micro / nanopore structure on the modified aluminum foil layer refers to a porous structure with micropores and / or nanopores. The modified aluminum foil layer has a side with the micro / nanopore structure. The depth of the pores can be 280-320 nm, for example, 290 nm, 300 nm, or 310 nm; the spacing between the pores can be 120-180 nm, for example, 140 nm, 150 nm, or 160 nm; and the diameter of the pores can be 5-40 nm, for example, 10 nm, 15 nm, 20 nm, 25 nm, or 30 nm. The presence of the micro / nanopore structure can significantly increase the physical anchoring area between the aluminum foil and carbon fibers, while also providing adhesion sites for subsequent silicon deposition.

[0015] In this invention, the modified aluminum foil layer has a micro-nano porous structure on one side, and the surface contact angle can be 60-80°, for example 62°, 63°, 65° or 70°.

[0016] In this invention, the method for preparing the modified aluminum foil layer preferably includes the following steps: laser drilling the surface of the aluminum foil, and then depositing silicon on one side of the drilled hole.

[0017] Preferably, the purity of the aluminum foil is ≥99.6%. After laser drilling and before silicon deposition, the specific surface area of ​​the aluminum foil can be 500-1000 m² / g, for example, 600 m² / g, 700 m² / g, 750 m² / g, 780 m² / g, or 820 m² / g; the diameter of the pores can be 5-20 nm, for example, 10 nm or 15 nm.

[0018] The aluminum foil generally needs to be washed and dried before use. The washing method can be conventional in the art, such as ultrasonic cleaning with anhydrous ethanol and / or deionized water; the ultrasonic time can be 10-60 minutes, for example 20 minutes or 30 minutes; the drying method can be conventional in the art, such as air drying at room temperature.

[0019] The laser drilling can be performed using a femtosecond laser or a nanosecond laser. The laser wavelength for laser drilling is, for example, 1064 nm. The drilling spacing can be 50-300 nm, such as 100 nm, 150 nm, or 200 nm. During the laser drilling process, the etch depth per pulse can be 4-6 nm, such as 5 nm. By controlling the number of pulses, the hole depth can be ensured to be 280-320 nm, such as 300 nm. If the laser drilling is a femtosecond laser, the energy density can be 6-10 J / cm², such as 8 J / cm²; the scanning speed can be 400-600 μm / s, such as 500 μm / s. If the laser drilling is a nanosecond laser, the energy density can be 10-14 J / cm², such as 12 J / cm²; the scanning speed can be 280-320 μm / s, such as 300 μm / s.

[0020] In one specific implementation, the laser drilling is a femtosecond laser with a laser energy density of 8 J / cm² and a scanning speed of 500 μm / s.

[0021] In a preferred embodiment, the laser drilling is a femtosecond laser with a laser energy density of 8 J / cm², a scanning speed of 500 μm / s, and a drilling spacing of 150 nm. The drilling depth is controlled to be 300 nm by etching a depth of 5 nm per pulse and accumulating 60 pulses.

[0022] In one specific implementation, the laser drilling is a nanosecond laser with a laser energy density of 12 J / cm² and a scanning speed of 300 μm / s.

[0023] In a preferred embodiment, the laser drilling is a nanosecond laser with a laser energy density of 12 J / cm², a scanning speed of 300 μm / s, and a drilling spacing of 150 nm. The drilling depth is controlled to be 300 nm by etching a depth of 5 nm per pulse and accumulating 60 pulses.

[0024] After laser drilling, washing and drying are generally required. The washing method can be conventional in the art, such as ultrasonic cleaning with deionized water; the ultrasonic cleaning time can be 3-10 minutes, for example, 5 minutes or 10 minutes. The drying temperature can be 40-80℃; the drying time can be 0.5-4 hours. This is to avoid residue affecting the uniformity of silicon deposition.

[0025] The silicon deposition method is preferably chemical vapor deposition (CVD). The silicon deposition is generally performed in a CVD apparatus, such as a plasma-enhanced CVD apparatus. The presence of the silicon layer can form a dense protective film on the aluminum foil surface, improving resistance to electrolyte corrosion and high-temperature stability. Simultaneously, the hydroxyl groups on the silicon layer surface can form chemical bonds with the active sites of the carbon fibers, further enhancing interfacial adhesion.

[0026] In the chemical vapor deposition process, the silicon source used can be conventional in the art, preferably one or more of tetraethoxysilane, tetramethoxysilane, silane, and hexamethyldisiloxane; the carrier gas can be conventional in the art, such as argon; the carrier gas flow rate can be 20-100 sccm, such as 30 sccm, 40 sccm, 50 sccm, 60 sccm, or 80 sccm; the reaction temperature can be 150-380℃, such as 180℃, 200℃, 220℃, 250℃, 300℃, or 350℃; the working gas pressure can be 4-20 Pa, such as 5 Pa, 8 Pa, 10 Pa, 15 Pa, or 20 Pa; the radio frequency power can be 75-105 W, such as 80 W or 90 W; and the deposition time can be 30-90 min, such as 30 min, 35 min, 40 min, 60 min, or 85 min. The deposition temperature must be matched with the heat resistance of the aluminum foil to avoid deformation of the aluminum foil.

[0027] In one specific implementation, the chemical vapor deposition process involves a reaction temperature of 250°C and a deposition time of 40 minutes.

[0028] In a preferred embodiment, during the chemical vapor deposition process, the reaction temperature is 250°C, the working pressure is 5Pa, the radio frequency power is 80W, and the deposition time is 40min.

[0029] In one specific implementation, during the chemical vapor deposition process, the reaction temperature is 200°C, the working pressure is 5Pa, the radio frequency power is 80W, and the deposition time is 40min.

[0030] In a preferred embodiment, the chemical vapor deposition process is carried out at a reaction temperature of 200°C and a deposition time of 40 min.

[0031] In this invention, the hydrophilic active groups on the surface of the activated carbon fiber layer can be hydroxyl and / or carboxyl groups; the surface contact angle of the activated carbon fiber layer can be 30-55°, for example, 35°, 40°, 42°, 45°, 46°, 48°, or 50°; the surface roughness Ra of the activated carbon fiber layer can be 0.4-1 μm, for example, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, or 0.9 μm. The synergistic effect of active sites such as hydroxyl and carboxyl groups with the rough surface can significantly improve the interfacial affinity between carbon fibers and modified aluminum foil, solving the core problem of non-wetting in traditional composites.

[0032] In this invention, the diameter of the single filament of the carbon fiber in the activated carbon fiber layer can be 6-8 μm, for example 6.5 μm, 7 μm or 7.5 μm; the carbon fibers in the activated carbon fiber layer are preferably arranged in a unidirectional layup; the layup density of the activated carbon fiber layer can be 180-220 g / m², for example 190 g / m², 200 g / m² or 210 g / m²; unidirectional layup can ensure that the strength of the composite material is maximized in the direction of stress, which is suitable for the impact and stacking pressure requirements of high-pressure equipment.

[0033] In one specific implementation, the layup density of the activated carbon fiber layer is 200 g / m².

[0034] In this invention, the activated carbon fiber layer is preferably obtained by plasma etching or chemical etching of the carbon fiber.

[0035] The carbon fiber can be a carbon fiber bundle, such as a T700 type PAN-based carbon fiber bundle; the specification of the carbon fiber bundle can be 12K.

[0036] In one specific implementation, the carbon fiber is a T700 type PAN-based carbon fiber bundle with a diameter of 7μm.

[0037] The carbon fibers generally need to be cleaned and dried before use. The cleaning method can be conventional in the art, such as ultrasonic treatment followed by washing with deionized water. The ultrasonic treatment power can be 140-160W; the ultrasonic treatment time can be 15-95min; and the ultrasonic treatment frequency can be conventional in the art, such as 40kHz.

[0038] The plasma etching process is typically performed in a plasma etching machine. The gas used is preferably a mixture of argon and oxygen. The volume ratio of argon to oxygen can be (2-4):1, for example, 3:1. The operating voltage during plasma etching can be 0.8-1.2 Pa, for example, 0.9 Pa, 1 Pa, or 1.1 Pa. The radio frequency power can be 140-160 W, for example, 150 W. The etching time can be 20-100 min, for example, 25 min, 30 min, 40 min, 60 min, or 95 min. After plasma etching, washing and drying are generally required. The washing method can be conventional in the art, such as ultrasonic cleaning with deionized water. During the plasma etching process, argon plasma can physically bombard the carbon fiber surface, forming a rough surface, while oxygen plasma can oxidize and generate hydroxyl and carboxyl active sites.

[0039] In one specific implementation, the plasma etching process uses argon and oxygen in a volume ratio of 3:1, with a working pressure of 1 Pa, a radio frequency power of 150 W, and an etching time of 30 min.

[0040] The chemical etching process generally refers to the surface treatment of carbon fibers using chemical reagents, and preferably includes the following steps: immersing the carbon fibers in an acid solution for ultrasonic treatment.

[0041] The acid in the acid solution includes one or a combination of nitric acid, sulfuric acid, and phosphoric acid; the mass fraction of the acid can be 10%-30%, for example, 10%, 12%, or 15%. The power of the ultrasonic treatment can be 90-130W, for example, 100W, 110W, or 120W; the time of the ultrasonic treatment can be 30-120min, for example, 50min, 60min, or 90min. The frequency of the ultrasonic treatment can be conventional in the art, for example, 40kHz. The acid solution can remove the inert layer on the carbon fiber surface through oxidation, while simultaneously introducing active groups.

[0042] In one specific implementation, the acid solution is a concentrated nitric acid solution with a mass fraction of 12%.

[0043] Following the ultrasonic treatment, according to conventional practice, washing and drying are generally required. The washing preferably includes the following process: first washing with deionized water until neutral, then washing with an alkaline solution, and finally washing with deionized water again. The alkaline solution may be a sodium bicarbonate solution; the mass fraction of the sodium bicarbonate solution may be 0.2-1.5%, for example, 0.5%. The alkaline washing time may be 2-10 minutes, for example, 5 minutes or 10 minutes. The drying is generally carried out in a vacuum dryer; the drying temperature may be 40-80°C; and the drying time may be 0.5-3 hours.

[0044] In this invention, the high-safety, weight-reducing packaging material for dual-high-performance devices can be configured as a sandwich-like layered composite structure of modified aluminum foil layer / activated carbon fiber layer / modified aluminum foil layer according to actual usage requirements. For example, it can be configured as modified aluminum foil layer / activated carbon fiber layer / modified aluminum foil layer / activated carbon fiber layer / modified aluminum foil layer, where the activated carbon fiber layer is located between the upper and lower modified aluminum foil layers, and the outermost layer is the modified aluminum foil layer.

[0045] The present invention also provides a method for preparing a high-safety, weight-reducing packaging material for dual-high-performance devices as described above, which includes the following steps: covering the upper and lower sides of the activated carbon fiber layer with the modified aluminum foil layer and then performing composite molding.

[0046] In this invention, the composite molding process must ensure a tight bond between the layers. The composite molding is generally performed in a hot press laminating machine. It is typically carried out under argon protection to prevent material oxidation during the molding process. During the composite molding process, the hot pressing temperature can be 250-360℃, for example, 280℃ or 300℃; the pressure can be 12-28MPa, for example, 15 MPa or 20 MPa; the heat preservation and pressure holding time can be 35-95min, for example, 45min or 60min; after the heat preservation and pressure holding is completed, it is preferably cooled slowly to room temperature at a rate of 4-6℃ / min to avoid excessive temperature difference leading to interlayer stress cracking. After demolding, an aluminum / carbon fiber composite packaging material is obtained.

[0047] The present invention also provides a battery comprising a battery core and a dual-high device, high safety, and weight-reducing encapsulation material as described above for encapsulation.

[0048] In this invention, the battery core can be a single cell or a battery module.

[0049] In this invention, when the battery is a solid-state battery, the battery core generally includes a positive electrode, a negative electrode, and a solid electrolyte; when the battery is a non-solid-state battery, the battery core generally includes a positive electrode, a negative electrode, a separator, and an electrolyte.

[0050] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present invention.

[0051] The reagents and raw materials used in this invention are all commercially available.

[0052] The positive and progressive effects of this invention are as follows:

[0053] In terms of lightweighting, the composite packaging material of this invention can reduce density and achieve a high weight reduction rate. The low density of the carbon fiber layer and the micro-nano porous structure of the modified aluminum foil contribute to the weight reduction effect. It is suitable for the portability requirements of laser power supplies and the load reduction requirements of multi-module stacking of peak-modulation and frequency-modulation power supplies, while avoiding the problem of traditional polymer composite materials requiring additional support structures.

[0054] In terms of safety, the composite material interface shear strength is greatly improved through the synergistic design of activated carbon fiber, micro-nano porous aluminum foil and silicon layer. The dense protective effect of silicon layer makes the material difficult to be corroded by electrolyte, effectively solving the problems of electrolyte erosion and high temperature aging in the long-term use of high-temperature equipment.

[0055] In terms of structural strength, the unidirectionally laid carbon fiber and modified aluminum foil form a synergistic reinforcement, which greatly improves the tensile strength and flexural strength of the composite material. The instantaneous impact and stacking load during high-power power supply operation will not cause material deformation, ensuring that the internal battery cell is not damaged by external forces, and has significant potential for industrial applications. Attached Figure Description

[0056] Figure 1 This is a schematic diagram of the aluminum / carbon fiber composite materials prepared in Examples 1-4. Detailed Implementation

[0057] The present invention is further illustrated below by way of embodiments, but the invention is not limited to the scope of the embodiments described herein. Experimental methods in the following embodiments that do not specify specific conditions were performed according to conventional methods and conditions, or as selected according to the product instructions.

[0058] Example 1

[0059] Step (1): Take T700 type PAN-based carbon fiber bundle (Toray, single filament diameter 7μm), put it into analytical grade anhydrous ethanol (Sinopharm, analytical grade), and ultrasonically clean it for 30 min at 150W power and 40kHz frequency to remove surface oil. Then rinse it three times with deionized water and vacuum dry it at 80℃ for 2 h. Place the dried carbon fiber bundle in a plasma etching machine (PT-100 type, Zhongke Keyi), with a working gas pressure of 0.1-10Pa, and introduce a mixture of argon and oxygen with a volume ratio of 3:1 and a purity of 99.99%. Adjust the working gas pressure to 1Pa and the radio frequency power to 150W, and etch for 30 min. After etching, take it out and ultrasonically clean it with deionized water for 10 min, and vacuum dry it at 60℃ for 1 h to obtain surface activated carbon fiber with a surface contact angle reduced to 45° and a surface roughness Ra=0.8μm.

[0060] Step (2): Take 1060 pure aluminum foil (China Aluminum, thickness 0.2mm, purity ≥99.6%, initial specific surface area 0.8m² / g), and ultrasonically clean it for 20min each with analytical grade anhydrous ethanol and deionized water. After air-drying at room temperature, use a femtosecond laser drilling device (YL-FEM-1064, Han's Laser, wavelength 1064nm, pulse width 50fs, maximum power 50W) to drill holes on one side. Set the laser energy density to 8J / cm², scanning speed to 500μm / s, and drilling spacing to 150nm. Control the drilling depth to 300nm by etching a depth of 5nm per pulse and accumulating 60 pulses. After drilling, ultrasonically clean it with deionized water for 5min to remove residues in the holes, and dry it at 60℃ for 1h. Then, use a specific surface area and porosity analyzer (BET-3000) to analyze the surface area and porosity. The surface area of ​​the perforated aluminum foil was confirmed to be 780 m² / g and the pore size to be 20 nm after testing with a McMurray Technology (MTT). The perforated aluminum foil was then placed in a plasma-enhanced chemical vapor deposition (PECVD-300, Shenyang Keyi) system with the perforated side facing up. Tetraethoxysilane (Aladdin, 99.9% purity) was used as the silicon source, and argon gas with 99.99% purity was used as the carrier gas. The carrier gas flow rate was 50 sccm, the reaction temperature was set to 250℃, the working pressure to 5 Pa, and the radio frequency power to 80 W. The deposition time was 40 min, resulting in a modified aluminum foil with silicon-loaded pores and a surface contact angle of 62°.

[0061] Step (3): The activated carbon fiber bundles are arranged in a unidirectional layup manner with a layup density of 200 g / m². Modified aluminum foil is covered on both sides of the carbon fiber layer. The aluminum foil has a porous structure and the side with the silicon deposited layer is in contact with the carbon fiber layer to form an "aluminum foil-carbon fiber-aluminum foil" sandwich structure with a total thickness of 1.0 mm. Each layer of aluminum foil accounts for 10% and carbon fiber accounts for 80%. The layup structure is placed in a hot press laminating machine (HP-50 type, Shanghai Bairuo), and argon gas with a purity of 99.99% and a flow rate of 100 sccm is introduced. The temperature is set at 280℃ and the pressure is 15 MPa. The temperature and pressure are maintained for 45 min. Then, the temperature is reduced to room temperature at a rate of 5℃ / min. The aluminum-carbon fiber composite packaging material is demolded.

[0062] Performance tests were conducted on the material: the composite interfacial shear strength was measured to be 28 MPa using an interfacial shear strength tester (IST-2000, Shimadzu), indicating that aluminum and carbon fiber achieved effective wetting and bonding; the material density was 2.1 g / cm³ (pure aluminum foil density is 2.7 g / cm³), with a weight reduction rate of 22.2%; the tensile strength was 520 MPa and the flexural strength was 480 MPa, meeting the impact resistance and deformation resistance requirements for battery module packaging materials; after aging for 1000 hours at 85℃ and 85% relative humidity, the interfacial shear strength retention rate was ≥90%, with no delamination.

[0063] Example 2

[0064] Step (1): Take T700 type PAN-based carbon fiber bundle (Toray, single filament diameter 7μm), put it into analytical grade anhydrous ethanol (Sinopharm, analytical grade), and ultrasonically clean it for 30 min at 150W power and 40kHz frequency to remove surface oil. Then rinse it three times with deionized water and vacuum dry it at 80℃ for 2 h. Put the dried carbon fiber bundle into a 12% mass fraction concentrated nitric acid solution (Sinopharm, analytical grade), and ultrasonically immerse it at 100W power and 40kHz frequency for 60 min at room temperature. After etching, rinse it with deionized water until pH=7, then neutralize it with 0.5% mass fraction sodium bicarbonate solution for 5 min, and finally rinse it clean with deionized water and vacuum dry it at 60℃ for 1 h to obtain surface activated carbon fiber with a surface contact angle reduced to 48° and a surface roughness Ra=0.6μm.

[0065] Step (2): Completely consistent with Step (2) of Prototype Implementation Example 1.

[0066] Step (3): Completely consistent with Step (3) of Prototype Example 1.

[0067] Performance test results: interfacial shear strength 25 MPa; material density 2.09 g / cm³ (weight reduction rate 22.6%, slightly better than the prototype); tensile strength 490 MPa, flexural strength 450 MPa; after aging at 85℃ and 85% relative humidity for 1000 h, the interfacial shear strength retention rate is 88%, with no delamination.

[0068] Example 3

[0069] Step (1): Step (1) of Example 1 is completely identical.

[0070] Step (2): Take 1060 pure aluminum foil (China Aluminum, thickness 0.2mm, purity ≥99.6%, initial specific surface area 0.8m² / g), and ultrasonically clean it for 20min each with analytical grade anhydrous ethanol and deionized water. After air drying at room temperature, use a nanosecond laser drilling device (YL-NEM-1064 type, Han's Laser, wavelength 1064nm, pulse width 10ns, maximum power 30W) to drill holes on one side. Set the laser energy density to 12J / cm², scanning speed to 300μm / s, and drilling spacing to 150nm. Control the drilling depth to 300nm by etching a depth of 5nm per pulse and accumulating 60 pulses. After drilling, ultrasonically clean it with deionized water for 5min to remove residues in the holes, and dry it at 60℃ for 1h. The specific surface area of ​​the aluminum foil after drilling is confirmed to be 750m² / g by BET analyzer. Then, put the drilled aluminum foil into PECVD. The equipment is set with the perforated side of the aluminum foil facing upwards. Tetraethoxysilane (Aladdin, 99.9% purity) is used as the silicon source, and argon gas with 99.99% purity is used as the carrier gas. The carrier gas flow rate is 50 sccm. The reaction temperature is set to 250℃, the working pressure to 5Pa, and the radio frequency power to 80W. After deposition for 40 minutes, a modified aluminum foil with silicon-loaded channels and a contact angle of 63° is obtained.

[0071] Step (3): Completely consistent with step (3) of prototype embodiment 1, the aluminum-carbon fiber composite packaging material is obtained by demolding.

[0072] Performance test results: interfacial shear strength 26MPa; material density 2.1g / cm³ (weight reduction rate 22.2%); tensile strength 505MPa, flexural strength 465MPa; after aging at 85℃ and 85% relative humidity for 1000h, the interfacial shear strength retention rate is 89%, with no delamination; and the aluminum foil perforation efficiency is 40% higher than that of Example 1, and the single sheet processing time is shortened from 15min to 9min.

[0073] Example 4

[0074] Step (1): Completely consistent with Step (1) of Example 1.

[0075] Step (2): Take 1060 pure aluminum foil (China Aluminum, thickness 0.2mm, purity ≥99.6%, initial specific surface area 0.8m² / g), and clean it with analytical grade anhydrous ethanol and deionized water for 20min each. After air drying at room temperature, the femtosecond laser drilling parameters are completely consistent with Step (2) of Example 1, with a drilling depth of 300nm and a specific surface area of ​​780m² / g. Then, place the drilled aluminum foil into a plasma enhanced chemical vapor deposition equipment (PECVD-300, Shenyang Keyi), using tetraethoxysilane (Aladdin, purity 99.9%) as the silicon source and argon gas with purity of 99.99% as the carrier gas (flow rate 50sccm). Set the reaction temperature to 200℃, the working pressure to 5Pa, and the radio frequency power to 80W. Deposit for 40min to obtain modified aluminum foil with silicon-loaded channels and a surface contact angle of 65°.

[0076] Step (3): Completely consistent with step (3) of prototype embodiment 1, the aluminum-carbon fiber composite packaging material is obtained by demolding.

[0077] Performance test results: interfacial shear strength 24MPa; material density 2.1g / cm³ (weight reduction rate 22.5%); tensile strength 485MPa, flexural strength 440MPa; after aging at 85℃ and 85% relative humidity for 1000h, the interfacial shear strength retention rate is 86%, with no delamination.

[0078] Comparative Example 1

[0079] As a control group for pure aluminum foil, 1060 pure aluminum foil (China Aluminum, thickness 1.0 mm, purity ≥99.6%) was used to ultrasonically clean the foil for 20 min each with analytical grade anhydrous ethanol (China National Pharmaceutical Group Co., Ltd., analytical grade) and deionized water. After being air-dried at room temperature, it was used directly as the packaging material for comparison without any surface modification or composite treatment.

[0080] The performance test results are as follows: density 2.7 g / cm³, no weight reduction effect, weight is 28.6% higher than that of Example 1, tensile strength 125 MPa, only 24.1% of that of Example 1, structural strength is significantly insufficient, bending strength 130 MPa, only 27.1% of that of Example 1, unable to withstand the stacking pressure and vibration impact of high power equipment, after aging for 1000 hours at 85℃ and 85% relative humidity, slight oxidation corrosion appeared on the surface, tensile strength retention rate 85%, although corrosion resistance is acceptable, the shortcoming in strength cannot meet the requirements of high power equipment.

[0081] Comparative Example 2

[0082] This serves as the control group for untreated aluminum / carbon fiber composites.

[0083] Step (1): Take T700 type PAN-based carbon fiber bundle (Toray, single filament diameter 7μm), ultrasonically clean it for 30min with analytical grade anhydrous ethanol (Sinopharm, analytical grade) and vacuum dry it at 80℃ for 2h. No plasma etching or chemical activation treatment was performed. The surface contact angle is still 105° and the surface roughness Ra=0.1μm.

[0084] Step (2): Take 1060 pure aluminum foil (China Aluminum, thickness 0.2mm, purity ≥99.6%) and ultrasonically clean it for 20 minutes using only analytical grade anhydrous ethanol and deionized water.

[0085] Step (3): Following the layup method of prototype Example 1, composite molding is performed using the same hot pressing parameters to obtain aluminum / carbon fiber composite material.

[0086] The performance test results are as follows: density 2.08 g / cm³, weight loss rate 22.9%, interfacial shear strength 4.8 MPa, only 17.1% of that of Example 1. Due to the non-wetting of aluminum and carbon fiber surfaces, the interfacial bonding is extremely weak. The tensile strength is 180 MPa, only 34.6% of that of Example 1. Interfacial peeling leads to a significant decrease in overall strength. The flexural strength is 165 MPa, only 34.4% of that of the prototype Example 1. The interface is prone to cracking under stress, resulting in poor structural stability. After aging for 1000 hours at 85°C and 85% relative humidity, the interface completely delaminates, and the carbon fiber peels off from the aluminum foil, losing its packaging and protective function. The untreated interface cannot resist environmental erosion and has extremely poor stability.

[0087] Effect Example

[0088] (1) Schematic diagram of aluminum / carbon fiber composite structure

[0089] Schematic diagrams of the aluminum / carbon fiber composite materials prepared in Examples 1-4 are shown below. Figure 1 As shown.

[0090] (2) Performance testing

[0091] Density test: According to GB / T 2951.11-2008 "General test methods for insulation and sheath materials of cables and optical cables - Part 11: Density determination method - density bottle method", an electronic densitometer (MDJ-300A, Shanghai Jingke) was used. Three 10mm×10mm samples were taken, their masses were measured, and they were placed in a density bottle. The volume of water displaced was recorded, and the average density was calculated.

[0092] Tensile strength test: According to GB / T 1447-2005 "Test method for tensile properties of fiber reinforced plastics", a universal testing machine (CMT5105, METS industrial system) was used to prepare 5 dumbbell-shaped specimens (gauge length 25mm, width 6mm), with a loading rate of 2mm / min. The maximum load at fracture was recorded, and the average tensile strength was calculated.

[0093] Bending strength test: According to GB / T 1449-2005 "Test method for bending properties of fiber reinforced plastics", the three-point bending method was adopted, the sample size was 80mm×10mm×1.0mm, the support span was 40mm, the loading rate was 2mm / min, and the average bending strength was calculated.

[0094] High temperature and high humidity aging performance test: According to GB / T 2423.4-2008 "Environmental testing - Part 2: Test methods - Test Db: Alternating damp heat (12h + 12h cycle)", the sample was placed in a constant temperature and humidity chamber (THB-1000, Dongguan Qinzhuo) with the temperature set at 85℃ and relative humidity at 85%. After aging for 1000h, the above tensile strength test was repeated, the tensile strength retention rate was calculated, and the surface condition of the sample was recorded.

[0095] Based on the above experimental results, it can be seen that although Comparative Example 1 has basic corrosion resistance, its high density and low strength cannot meet the requirements of lightweighting and structural support for high-power equipment. Although Comparative Example 2 achieves lightweighting due to the addition of carbon fiber, it does not solve the problem of non-wetting between aluminum and carbon fiber, resulting in extremely poor interfacial bonding and failure to meet the standards for strength and stability. In contrast, the embodiments of the present invention achieve weight reduction and improve interfacial shear strength through the synergistic treatment of carbon fiber plasma etching, aluminum foil surface treatment, and PECVD silicon deposition. The tensile / bending strength meets the stringent operating conditions of high-power equipment, highlighting the necessity and innovation of the process of the present invention.

[0096] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A high-safety, weight-reducing packaging material for dual-high-performance devices, characterized in that, It includes a sandwich-like layered composite structure consisting of a modified aluminum foil layer, an activated carbon fiber layer, and a modified aluminum foil layer. The activated carbon fiber layer is located between the upper and lower modified aluminum foil layers. The side of the modified aluminum foil layer that is in direct contact with the activated carbon fiber layer has a micro-nano pore structure, and silicon is deposited in the pores of the micro-nano pore structure. The surface of the activated carbon fiber layer has hydrophilic active groups.

2. The dual-high device high-safety weight-reducing packaging material as described in claim 1, characterized in that, The encapsulation material satisfies one or more of the following conditions: (1) The overall thickness of the encapsulation material is 0.8-1.2 mm, for example 0.9 mm, 1 mm or 1.1 mm; (2) The activated carbon fiber layer accounts for 78-82% of the total thickness of the encapsulation material, for example, 79%, 80% or 81%; (3) The modified aluminum foil layer has a micro-nano pore structure on one side, and the pore depth is 280-320nm, for example 290nm, 300nm or 310nm; (4) The modified aluminum foil layer has a micro-nano pore structure on one side, and the pore spacing is 120-180nm, for example 140nm, 150nm or 160nm; (5) The modified aluminum foil layer has a micro-nano pore structure on one side, with the diameter of the pores being 5-40 nm, for example 10 nm, 15 nm, 20 nm, 25 nm or 30 nm; (6) The modified aluminum foil layer has a micro-nano pore structure on one side, and the surface contact angle is 60-80°, for example 62°, 63°, 65° or 70°; (7) The hydrophilic active groups on the surface of the activated carbon fiber layer are hydroxyl and / or carboxyl groups; (8) The surface contact angle of the activated carbon fiber layer is 30-55°, for example 35°, 40°, 42°, 45°, 46°, 48° or 50°; (9) The surface roughness Ra of the activated carbon fiber layer is 0.4-1 μm, for example 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm or 0.9 μm; (10) The diameter of the single filament of the carbon fiber in the activated carbon fiber layer is 6-8 μm, for example 6.5 μm, 7 μm or 7.5 μm; (11) The carbon fibers in the activated carbon fiber layer are arranged in a unidirectional layup manner; (12) The layup density of the activated carbon fiber layer is 180-220 g / m², for example 190 g / m², 200 g / m² or 210 g / m².

3. The dual-high device high-safety weight-reducing packaging material as described in claim 1, characterized in that, The method for preparing the modified aluminum foil layer includes the following steps: laser drilling holes in the surface of the aluminum foil, and then depositing silicon on one side of the drilled holes; And / or, the activated carbon fiber layer is obtained by plasma etching or chemical etching of carbon fibers.

4. The dual-high device high-safety weight-reducing packaging material as described in claim 3, characterized in that, The purity of the aluminum foil is ≥99.6%; And / or, after the laser drilling and before the silicon deposition, the specific surface area of ​​the aluminum foil is 500-1000 m² / g, for example 600 m² / g, 700 m² / g, 750 m² / g, 780 m² / g or 820 m² / g. And / or, after the laser drilling and before the silicon deposition, the diameter of the hole is 5-20 nm, for example 10 nm or 15 nm.

5. The dual-high device high-safety weight-reducing packaging material as described in claim 3, characterized in that, The laser drilling meets one or more of the following conditions: (1) The laser drilling equipment used is a femtosecond laser or a nanosecond laser; (2) The drilling spacing of the laser drilling is 50-300nm, for example 100nm, 150nm or 200nm; (3) During the laser drilling process, the etch depth per pulse is 4-6 nm, for example 5 nm; (4) During the laser drilling process, the hole depth is ensured to be 280-320nm, for example, 300nm, by controlling the number of pulses; (5) If the laser drilling is a femtosecond laser with an energy density of 6-10 J / cm², for example 8 J / cm²; (6) If the laser drilling is a femtosecond laser, the scanning speed is 400-600 μm / s, for example 500 μm / s; (7) If the laser drilling is a nanosecond laser with an energy density of 10-14 J / cm², for example 12 J / cm²; (8) If the laser drilling is a nanosecond laser, the scanning speed is 280-320μm / s, for example 300μm / s.

6. The dual-high device high-safety weight-reducing packaging material as described in claim 3, characterized in that, The silicon deposition method is chemical vapor deposition; In the chemical vapor deposition process, the silicon source used is preferably one or more of tetraethoxysilane, tetramethoxysilane, silane, and hexamethyldisiloxane; the carrier gas flow rate is preferably 20-100 sccm; the reaction temperature is preferably 150-380℃, for example 180℃, 200℃, 220℃, 250℃, 300℃, or 350℃; the working gas pressure is preferably 4-20 Pa; the radio frequency power is preferably 75-105 W; and the deposition time is preferably 30-90 min.

7. The dual-high device high-safety weight-reducing packaging material as described in claim 3, characterized in that, The method for preparing the activated carbon fiber layer satisfies one or more of the following conditions: (1) The carbon fiber is a carbon fiber bundle, for example, a T700 type PAN-based carbon fiber bundle; (2) The gas used in the plasma etching process is a mixture of argon and oxygen; The volume ratio of argon to oxygen is preferably (2-4):1, for example 3:1; (3) During the plasma etching process, the working voltage is 0.8-1.2 Pa, for example 0.9 Pa, 1 Pa or 1.1 Pa; (4) During the plasma etching process, the radio frequency power is 140-160W, for example 150W; (5) The plasma etching time is 20-100 min, for example 25 min, 30 min, 40 min, 60 min or 95 min; (6) The chemical etching process includes the following steps: placing the carbon fiber in an acid solution for ultrasonic treatment.

8. A method for preparing a dual-high device high-security weight-reducing packaging material as described in any one of claims 1-7, characterized in that, The process includes the following steps: covering the upper and lower sides of the activated carbon fiber layer with the modified aluminum foil layer and then performing composite molding.

9. The method for preparing the high-safety, weight-reducing packaging material for dual-high-performance devices as described in claim 8, characterized in that, The composite molding satisfies one or more of the following conditions: (1) The composite molding is carried out in a hot press composite machine; (2) During the composite molding process, the hot pressing temperature is 250-360℃, for example 280℃ or 300℃; (3) During the composite molding process, the pressure is 12-28 MPa, for example 15 MPa or 20 MPa; (4) During the composite molding process, the heat preservation and pressure preservation time is 35-95 min, for example 45 min or 60 min.

10. A battery, characterized in that, It includes the battery core and the dual-high device high safety weight reduction packaging material as described in any one of claims 1-7.

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