Composite nylon material and preparation method thereof, aluminum-plastic film, battery, battery pack and electric equipment

Abstract

The invention provides a composite nylon material and a preparation method thereof, an aluminum-plastic film, a battery, a battery pack and electric equipment. The composite nylon material comprises a filler and nylon, the critical shear rate of the composite nylon material is 1s <-1 >-1200s <-1 >, and the viscosity increase of the composite nylon material is greater than 0. The composite nylon material has good impact resistance, and can significantly improve the safety of the battery on the premise of meeting application requirements.

Description

Technical Field

[0001] This invention belongs to the field of battery energy technology, and relates to a composite nylon material, and more particularly to a composite nylon material and its preparation method, aluminum-plastic film, battery, battery pack and electrical equipment. Background Technology

[0002] Currently, nylon is widely used in aluminum-plastic films for batteries due to its high strength, puncture resistance, and high-temperature resistance, resulting in explosive growth in its usage. However, during long-term use, nylon's insufficient impact resistance can lead to a decline in the mechanical properties of the aluminum-plastic film, posing safety risks and affecting battery safety.

[0003] Therefore, it is necessary to develop a new composite nylon material to effectively improve the impact resistance of nylon. Summary of the Invention

[0004] To address the aforementioned shortcomings, this invention provides a composite nylon material with good impact resistance, which can significantly improve battery safety while meeting application requirements.

[0005] The present invention also provides a method for preparing the above-mentioned composite nylon material. The composite nylon material prepared by this method has good impact resistance and can effectively improve the safety of the battery.

[0006] The present invention also provides an aluminum-plastic film, comprising the above-mentioned composite nylon material or the composite nylon material prepared by the above-mentioned preparation method. Therefore, the aluminum-plastic film has high impact resistance and can effectively improve the safety of the battery.

[0007] The present invention also provides a battery comprising the above-mentioned composite nylon material, or the composite nylon material prepared by the above-mentioned preparation method, or the above-mentioned aluminum-plastic film, thus the battery has a long service life and high safety.

[0008] The present invention also provides a battery pack comprising the above-mentioned composite nylon material, or the composite nylon material prepared by the above-mentioned preparation method, or the above-mentioned aluminum-plastic film, or the above-mentioned battery, thus the battery pack has a long service life and high safety.

[0009] The present invention also provides an electrical device comprising the above-mentioned composite nylon material, or the composite nylon material prepared by the above-mentioned preparation method, or the above-mentioned aluminum-plastic film, or the above-mentioned battery, or the above-mentioned battery pack. Therefore, the electrical device has a long service life and high safety.

[0010] The first aspect of this invention provides a composite nylon material, comprising a filler and nylon; the critical shear rate of the composite nylon material is 1 s. -1-1200s -1 The viscosity increase of the composite nylon material is greater than 0.

[0011] The composite nylon material described above, wherein the viscosity increase of the composite nylon material is 5-600, preferably 50-600; and / or, the critical shear rate of the composite nylon material is 1 s. -1 -1000s -1 .

[0012] The composite nylon material described above, wherein the filler includes at least one of inorganic fillers and biodegradable fillers.

[0013] The composite nylon material described above, wherein the filler surface contains at least one of amino, carboxyl, epoxy, isocyanate, amide, siloxane, long-chain alkyl, quaternary ammonium salt, and phosphate ester groups, preferably amino and / or epoxy.

[0014] The composite nylon material as described above, wherein the inorganic filler includes at least one of silicon dioxide, titanium dioxide, aluminum oxide, zinc oxide, calcium carbonate, and magnesium calcium carbonate; and / or, the biodegradable filler includes at least one of corn starch, potato starch, and sweet potato starch.

[0015] In the composite nylon material described above, when the filler includes inorganic filler, the inorganic filler accounts for 0.5wt%-11wt% of the mass percentage of the composite nylon material, preferably 1wt%-11wt%; when the filler includes biodegradable filler, the biodegradable filler accounts for 3wt%-35wt% of the mass percentage of the composite nylon material, preferably 5wt%-35wt%.

[0016] The composite nylon material as described above further includes a dispersant, wherein the dispersant accounts for 10wt%-40wt% of the mass of the composite nylon material.

[0017] The composite nylon material as described above, wherein the dispersant includes at least one selected from polyols, polyurethanes, polydimethylsiloxanes, silicone oils, ethanol, isopropanols, ethylene glycol, and mineral oils.

[0018] The composite nylon material as described above, wherein the nylon includes at least one of polycaprolactam, polyhexamethylene adipamide, polydecanolactam, polyundecanolactam, polydodecanolactam, polyhexamethylene adipamide, polydodecanoylhexamethylene diamine, polyhexamethylene terephthalamide, polynonadiamine terephthalamide, and polydecanoyl terephthalamide.

[0019] A second aspect of the present invention provides a method for preparing a composite nylon material according to the first aspect, comprising the following steps:

[0020] Nylon and filler are mixed to obtain a mixture, which is then melted and shaped to obtain a composite nylon material.

[0021] In the preparation method described above, the filler and dispersant are mixed before mixing the nylon and filler to obtain the mixture.

[0022] A third aspect of the present invention provides an aluminum-plastic film comprising an aluminum foil and a composite nylon layer disposed on one side of the aluminum foil, wherein the composite nylon layer comprises a composite nylon material as described in the first aspect or a composite nylon material prepared by the preparation method described in the second aspect.

[0023] The aluminum-plastic film as described above, wherein the aluminum-plastic film meets any of the following conditions: the thickness of the aluminum foil is 30μm-50μm; the thickness of the composite nylon layer is 8μm-30μm, preferably 10μm-30μm.

[0024] The aluminum-plastic film as described above further includes a polymer layer disposed on the other side of the aluminum foil.

[0025] The aluminum-plastic film as described above, wherein the polymer layer includes at least one of polypropylene and polyethylene; and / or, the thickness of the polymer layer is 20μm-60μm.

[0026] In the aluminum-plastic film described above, the peel strength of the composite nylon layer is 5N / cm-8N / cm.

[0027] A fourth aspect of the present invention provides a battery comprising the composite nylon material described in the first aspect, or the composite nylon material prepared by the preparation method described in the second aspect, or the aluminum-plastic film described in the third aspect.

[0028] The fifth aspect of the present invention provides a battery pack comprising the composite nylon material described in the first aspect, or the composite nylon material prepared by the preparation method described in the second aspect, or the aluminum-plastic film described in the third aspect, or the battery described in the fourth aspect.

[0029] The sixth aspect of the present invention provides an electrical device comprising the composite nylon material described in the first aspect, or the composite nylon material prepared by the preparation method described in the second aspect, or the aluminum-plastic film described in the third aspect, or the battery described in the fourth aspect, or the battery pack described in the fifth aspect.

[0030] The composite nylon material provided by this invention comprises filler and nylon; the critical shear rate of the composite nylon material is 1 s. -1 -1200s -1The viscosity increase of the composite nylon material is greater than 0. In this invention, the composite nylon material obtained by modifying nylon with filler has a low critical shear rate and a viscosity increase greater than 0. The impact resistance of the composite nylon material is greatly improved, which can significantly improve the safety of the battery while meeting application requirements. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the composite nylon material of the present invention in one embodiment.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1-Composite nylon layer; 2-Aluminum foil; 3-Polymer layer. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0035] Currently, nylon is widely used in aluminum-plastic films for batteries due to its high strength, puncture resistance, and high-temperature resistance, resulting in explosive growth in its usage. However, during long-term use, nylon's insufficient tumescence can lead to a decline in the mechanical properties of the aluminum-plastic film, posing safety risks and affecting battery safety. Existing technologies often improve nylon's impact resistance through chemical modification, but it is difficult to balance strength and toughness. Furthermore, long-term use can lead to migration and peeling, reducing service life and severely impacting the mechanical properties and lifespan of the aluminum-plastic film.

[0036] The inventors discovered through research that adding fillers to nylon can reduce the critical shear rate of the material, allowing the material to undergo flow instability at low shear rates, resulting in changes in viscosity. When the viscosity increase is greater than 0, the material has good bulging properties, which can improve the mechanical properties of aluminum-plastic films when used in aluminum-plastic films.

[0037] Based on the above analysis, the first aspect of the present invention provides a composite nylon material, comprising a filler and nylon; the critical shear rate of the composite nylon material is 1 s. -1 -1200s -1 The viscosity increase of the composite nylon material is greater than 0.

[0038] For example, the critical shear rate of the composite nylon material can be 1 s. -1 10s -1 50s-1 100s -1 150s -1 200s -1 250s -1 300s -1 350s -1 400s -1 450s -1 500s -1 550s -1 600s -1 650s -1 700s -1 750s -1 800s -1 850s -1 900s -1 950s -1 1000s -1 1100s - Or 1200s -1 The viscosity increase of the composite nylon material can be 0.01, 5, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500 or 1000, or a range of any two values.

[0039] Critical shear rate refers to the point at which a fluid transitions from steady to unstable flow. When the actual shear rate exceeds the critical shear rate, the fluid viscosity changes from linear to nonlinear at this point. For dilatant fluids, the critical shear rate is the point at which viscosity increases rapidly and nonlinearly. Viscosity increase refers to the relative increase in viscosity as the shear rate increases after the shear rate exceeds the critical shear rate. When the viscosity increase is greater than 0, the material viscosity increases when the shear rate exceeds the critical shear rate. In this invention, the composite nylon material has a low critical shear rate and a viscosity increase greater than 0. Its viscosity increases under external pressure, improving its impact resistance. Therefore, the composite nylon material in this invention exhibits good impact resistance and can significantly improve battery safety while meeting application requirements.

[0040] In some embodiments, the critical shear rate and viscosity increase of the composite nylon material can be tested using a rotational rheometer (RS-CPS), as follows:

[0041] After uniformly heating the surface of the nylon layer and the interface between the nylon and aluminum foil layers for 3 minutes using a hair dryer on high heat, the nylon layer was peeled off from the aluminum foil layer. The resulting nylon layer was pulverized into nylon particles of approximately 1 mm using a liquid nitrogen cryogenic ball mill (YDQM-60). A solution was prepared according to the mass ratio of nylon particles:KH500:ethanol = 40:0.1:59.9. The resulting solution was dispersed in an ultrasonic homogenizer (VCX750) for 30 minutes, and then defoamed in an inert atmosphere to obtain a fluid solution. This fluid solution was then placed on the rotating rheometer (RS-CPS) turntable to test its rheological curve, with a shear rate set to 0.01 s⁻¹. -1 -1500s -1 The shear rate at which viscosity increases nonlinearly is the critical shear rate, and the viscosity at this point is η0. The highest viscosity value on the rheological curve is taken as the maximum viscosity η. max Viscosity increase = (η) max -η0) / η0.

[0042] In one specific embodiment, the viscosity increase of the composite nylon material is 5-600, preferably 50-600; and / or, the critical shear rate of the composite nylon material is 1 s. -1 -1000s -1 .

[0043] For example, the viscosity increase of the composite nylon material can be 5, 50, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, or 600, or a range of any two of these values. When the viscosity increase of the composite nylon material is within the above range, the viscosity increases within a certain range when subjected to external impact, which can effectively alleviate the stress generated by impact and collision on the battery cell and improve the impact resistance of the composite nylon material. The effect is even better when the viscosity increase of the composite nylon material is in the range of 50-600.

[0044] For example, the critical shear rate of the composite nylon material can be 1 s. -1 10s -1 50s -1 100s -1 150s -1 200s -1 250s -1 300s -1 350s -1 400s -1 450s -1 500s -1 550s -1 600s -1 650s -1 700s -1750s -1 800s -1 850s -1 900s -1 950s -1 Or 1000s -1 The critical shear rate of the composite nylon material is within the range specified above, or any two of these values ​​form a range. When the critical shear rate of the composite nylon material falls within this range, the composite nylon material exhibits superior impact resistance.

[0045] In one specific embodiment, the packing material includes at least one of inorganic packing material and biodegradable packing material.

[0046] Understandably, when the filler includes inorganic fillers, the inorganic fillers improve the ductility of the composite nylon material through physical filling and / or interfacial bonding, resulting in a higher viscosity increase and a stronger effect in relieving external stress, thus significantly improving the impact resistance of the composite nylon material. When the filler includes biodegradable fillers, the biodegradable fillers improve the ductility of the composite nylon material through biodegradation mechanisms and / or molecular structure design, achieving a certain viscosity increase while being biodegradable and environmentally friendly.

[0047] Specifically, the filler in this invention can be either unmodified or modified. There is no limitation on whether the filler is modified or not, nor is there any limitation on the specific modification method.

[0048] In one specific embodiment, the filler surface contains at least one of amino, carboxyl, epoxy, isocyanate, amide, siloxane, long-chain alkyl, quaternary ammonium salt, and phosphate ester groups, preferably amino and / or epoxy.

[0049] It is understandable that when the modified filler surface contains at least one of amino, carboxyl, epoxy, isocyanate, amide, siloxane, long-chain alkyl, quaternary ammonium salt, or phosphate ester groups, it is beneficial to strengthen the bonding force between the filler and nylon and improve the expansion plasticity of the composite nylon material. Specifically, the amino groups on the filler surface can form hydrogen bonds / covalent bonds with the amide bonds in nylon, and the epoxy groups on the filler surface can undergo ring-opening reactions with the amino / carboxyl groups in nylon. This results in a stronger bonding force between the filler and nylon, and superior expansion plasticity of the composite nylon material. Therefore, the effect is better when the filler surface contains amino and / or epoxy groups.

[0050] In one specific embodiment, the inorganic filler includes at least one of silicon dioxide, titanium dioxide, aluminum oxide, zinc oxide, calcium carbonate, and magnesium calcium carbonate; and / or, the biodegradable filler includes at least one of corn starch, potato starch, and sweet potato starch.

[0051] Specifically, when the inorganic filler includes at least one of silica, titanium dioxide, alumina, zinc oxide, calcium carbonate, and magnesium calcium carbonate, it has a better effect on improving the performance of the composite nylon material and is more conducive to commercialization; when the biodegradable filler includes at least one of corn starch, potato starch, and sweet potato starch, it has a better effect on improving the performance of the composite nylon material and is more conducive to commercialization.

[0052] In one specific embodiment, when the filler includes inorganic filler, the inorganic filler accounts for 0.5wt%-11wt% of the mass percentage of the composite nylon material, preferably 1wt%-11wt%; when the filler includes biodegradable filler, the biodegradable filler accounts for 3wt%-35wt% of the mass percentage of the composite nylon material, preferably 5wt%-35wt%.

[0053] For example, when the filler includes inorganic filler, the mass percentage of the inorganic filler in the composite nylon material can be 0.5 wt%, 1 wt%, 3 wt%, 5 wt%, 7 wt%, 9 wt%, or 11 wt%, or any combination of two of these values. When the mass percentage of the inorganic filler in the composite nylon material is greater than or equal to 0.5 wt%, it ensures a lower critical shear threshold and a faster response rate to external forces, thus improving the impact resistance of the composite nylon material. When the mass percentage of the inorganic filler in the composite nylon material is less than or equal to 11 wt%, the inorganic filler can be uniformly dispersed in the composite nylon material, avoiding the impact of uneven distribution on the mechanical properties of the composite nylon material. When the mass percentage of the inorganic filler in the composite nylon material is in the range of 0.5 wt% to 11 wt%, both advantages are achieved. When the mass percentage of the inorganic filler in the composite nylon material is in the range of 1 wt% to 11 wt%, the effect is even better.

[0054] For example, when the filler includes biodegradable filler, the mass percentage of the biodegradable filler in the composite nylon material can be 3 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, or 35 wt%, or any combination of two of these values. When the mass percentage of the biodegradable material in the composite nylon material is greater than or equal to 3 wt%, it ensures a lower critical shear threshold and a faster response rate to external forces, thus improving the impact resistance of the composite nylon material. When the mass percentage of the biodegradable material in the composite nylon material is less than or equal to 35 wt%, the biodegradable material can be uniformly dispersed in the composite nylon material, avoiding the impact of uneven distribution on the mechanical properties of the composite nylon material. When the mass percentage of the biodegradable material in the composite nylon material is in the range of 3 wt% to 35 wt%, both advantages are achieved. When the mass percentage of the biodegradable material in the composite nylon material is in the range of 5 wt% to 35 wt%, the effect is even better.

[0055] In some embodiments, the mass percentage of inorganic fillers and biodegradable materials in the composite nylon material can be tested using an infrared spectrometer (Avatar 360FITR Fourier transform infrared spectrometer), and the specific operation is as follows:

[0056] After uniformly heating the surface of the nylon layer and the interface between the nylon and aluminum foil layers for 3 minutes using a hair dryer on high heat, the nylon layer was peeled off from the aluminum foil layer. A 1.5cm diameter nylon disc was obtained by sampling with a φ1.5cm sampler. This nylon disc was then quantitatively characterized using an infrared spectrometer (Avatar 360FITR Fourier transform infrared spectrometer) to obtain an infrared spectrum. The spectrum is shown at 1100cm. -1 The absorption peaks around 3500-3000 cm⁻¹ are stretching vibration peaks of the Si-O-Si group, which can characterize SiO₂ in fluids; -1 The absorption peaks around 2920 cm⁻¹ are stretching vibration peaks of the -OH group. -1 The left and right sides are the vibrational peaks of CH, which can be used to jointly characterize starch; 1680-1650 cm⁻¹ -1 The absorption band at 670 cm⁻¹ is a characteristic absorption peak of the unsaturated C=O bond in NH₃CO (amide), which can characterize nylon. The peak area is obtained by integrating the corresponding absorption bands. Based on the ratio of the characteristic peak areas mentioned above, the content of SiO₂, starch, and nylon (polyamide) in the outer layer of nylon can be determined. The content of other fillers, such as TiO₂ at 670 cm⁻¹, can also be confirmed using a similar method. -1 There is a Ti-O absorption peak, and Al2O3 has an absorption peak at 640 cm⁻¹. -1 There is an Al-O absorption peak, and ZnO has an absorption peak at 540 cm⁻¹. -1 There is a Zn-O absorption peak, and CaCO3 has an absorption peak at 1420 cm⁻¹. -1 There is CO3 2- Absorption peak.

[0057] In one specific embodiment, the composite nylon material further includes a dispersant, wherein the dispersant accounts for 10wt%-40wt% of the mass of the composite nylon material.

[0058] For example, the dispersant can account for 10 wt%, 20 wt%, 30 wt%, or 40 wt% of the composite nylon material, or any combination of two of these values. When the dispersant accounts for the mass percentage of the composite nylon material within the above range, it can ensure that the filler is uniformly dispersed, avoid agglomeration, and maintain a reasonable spacing between particles, thereby improving the impact resistance and mechanical properties of the composite nylon material.

[0059] In some embodiments, the test method for the mass percentage of dispersant in the composite nylon material is the same as that for the mass percentage of filler in the composite nylon material, and will not be repeated here. For example, alcohol compounds at 3450 cm⁻¹ -1 There is an OH absorption peak; polyurethane has an absorption peak at 3320 cm⁻¹. -1 and 1705cm -1 It exhibits absorption peaks for NH and CO; polydimethylsiloxane shows an absorption peak at 2960 cm⁻¹. -1 and 1080cm -1 It exhibits absorption peaks for CH3 and Si-O-Si.

[0060] In one specific embodiment, the dispersant includes at least one selected from polyols, polyurethanes, polydimethylsiloxanes, silicone oils, ethanol, isopropanols, ethylene glycol, and mineral oils.

[0061] In one specific embodiment, the nylon includes at least one of polycaprolactam, polyhexamethylene adipamide, polydecanolactam, polyundecanolactam, polydodecanolactam, polyhexamethylene adipamide, polydodecanoylhexamethylene diamine, polyhexamethylene terephthalamide, polynonyl terephthalamide, and polydecanoyl terephthalamide.

[0062] The second aspect of the present invention provides a method for preparing a composite nylon material according to the first aspect, comprising the following steps: mixing nylon and filler to obtain a mixture, melting the mixture and then shaping it to obtain a composite nylon material.

[0063] In one specific embodiment, the filler and dispersant are mixed before the nylon and filler are mixed to obtain a mixture.

[0064] A third aspect of the present invention provides an aluminum-plastic film comprising an aluminum foil and a composite nylon layer disposed on one side of the aluminum foil, wherein the composite nylon layer comprises the composite nylon material as described above or the composite nylon material prepared by the preparation method as described above.

[0065] The present invention does not impose any special limitation on the aluminum foil, and commonly used materials in the field can be used; preferably, aluminum foil with a thickness of 30 to 50 μm is selected.

[0066] In one specific embodiment, the aluminum-plastic film meets any of the following conditions: the thickness of the aluminum foil is 30μm-50μm; the thickness of the composite nylon layer is 8μm-30μm, preferably 10μm-30μm.

[0067] For example, the thickness of the aluminum foil can be 30μm, 35μm, 40μm, 45μm, or 50μm, or any combination of two of these values. When the thickness of the aluminum foil is within the above range, it can effectively prevent the internal battery cell from contacting the outside world, ensuring the mechanical strength and corrosion resistance of the aluminum-plastic film. When used in batteries, it can improve the safety performance of the battery while also taking cost into consideration.

[0068] For example, the thickness of the composite nylon layer can be 8μm, 10μm, 15μm, 20μm, 25μm, or 30μm, or any combination of two of these values. When the thickness of the composite nylon layer is in the range of 8μm-30μm, it ensures that the aluminum-plastic film has good mechanical properties and stability (such as puncture resistance, abrasion resistance, and heat-sealing stability), and when used in batteries, it can also maintain the energy density of the cell. The effect is even better when the thickness of the composite nylon layer is in the range of 10μm-30μm.

[0069] In some embodiments, the thickness of the aluminum foil and the thickness of the composite nylon layer can be tested using a scanning electron microscope (FlexSEM1000), as follows:

[0070] The aluminum-plastic film was cut into 2cm × 1cm samples and treated with a CP ion polisher (IB-19510) to expose the cross-section. The ion beam energy was set to 5kV and the polishing speed was set to 500μm / h. The cross-section was then placed in a SEM (FlexSEM1000) and the thickness of different layers of the aluminum-plastic film was measured using the SEM scale to obtain the thickness of the aluminum foil and the composite nylon layer.

[0071] In one specific embodiment, the aluminum-plastic film further includes a polymer layer disposed on the other side of the aluminum foil.

[0072] It is understandable that, such as Figure 1 As shown, the aluminum-plastic film is composed of a composite nylon layer 1, an aluminum foil 2, and a polymer layer 3 in sequence. Adhesives are provided between the composite nylon material and the aluminum foil, and between the aluminum foil and the polymer layer, to enhance the bonding strength between the different layers. This invention does not impose special limitations on the adhesive; commonly used materials in the art can be used. Preferably, polyurethane-based adhesives, epoxy-polyolefin composite adhesives, or silane-modified polyether adhesives are selected, and the thickness of the adhesive layer is 5μm-10μm.

[0073] In one specific embodiment, the polymer layer includes at least one of polypropylene and polyethylene; and / or, the thickness of the polymer layer is 20 μm-60 μm.

[0074] It is understandable that when the polymer layer includes at least one of polypropylene and polyethylene, because polypropylene and polyethylene have good mechanical strength and chemical stability, the polymer layer can better meet the battery's requirements for encapsulation materials, thereby improving the battery's safety and durability.

[0075] For example, the thickness of the polymer layer can be 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, or 60μm, or any range of two of these values. When the thickness of the polymer layer is within the above range, it can ensure heat sealing reliability, prevent internal electrolyte penetration, buffer thermal deformation caused by cell temperature rise, and improve battery safety performance.

[0076] The testing method for the thickness of the polymer layer is the same as that for the thickness of aluminum foil and the thickness of the composite nylon layer, and will not be repeated here.

[0077] In one specific embodiment, the peel force of the composite nylon layer is 5N / cm-8N / cm.

[0078] For example, the peel force of the composite nylon layer can be 5 N / cm, 5.5 N / cm, 6 N / cm, 6.5 N / cm, 7 N / cm, 7.5 N / cm, or 8 N / cm, or a range of any two of these values. When the peel force of the composite nylon layer is within the above range, the composite nylon layer can adhere tightly to the aluminum foil, maintaining the integrity of the aluminum-plastic film during the use of the battery cell, protecting the internal battery cell, and improving the safety performance of the battery.

[0079] In some embodiments, the peel strength of the composite nylon layer can be tested using a universal testing machine (Instron 5965), as follows:

[0080] Cut the aluminum-plastic film into 25cm×10cm samples. Apply adhesive to one side of the nylon layer of the aluminum-plastic film. Fold the free end of the adhesive layer back 180° and clamp it into the upper clamp. Fix the other side of the substrate to the lower clamp. Fix the clamp on the universal testing machine (Instron5965). Pull the tape on the nylon layer and peel the nylon layer off the aluminum-plastic film at a 180° angle. The peeling speed is 500mm / min, and the effective peeling length is ≥100mm. Record the maximum peeling force.

[0081] The fourth aspect of the present invention provides a battery that has high safety because it comprises a composite nylon material of the first aspect, or a composite nylon material prepared by the preparation method of the second aspect, or an aluminum-plastic film of the third aspect.

[0082] It is understandable that a battery also includes a positive electrode, a negative electrode, and an electrolyte housed in an aluminum-plastic film.

[0083] It should be noted that the battery in this invention can be a pouch battery or a blade battery; specifically, the aforementioned battery can be any alkali metal ion battery such as a lithium-ion battery or a sodium-ion battery. More specifically, the aforementioned battery can be a liquid battery using a liquid electrolyte, or a solid-state battery or a semi-solid-state battery. The positive electrode, negative electrode, and electrolyte in the battery can be any known positive electrode, negative electrode, and electrolyte in a corresponding battery.

[0084] A fifth aspect of this invention provides a battery pack comprising a composite nylon material as described in the first aspect, or a composite nylon material prepared by the method described in the second aspect, or an aluminum-plastic film as described in the third aspect, or a battery as described in the fourth aspect. Therefore, this battery pack has high safety.

[0085] Generally, a battery pack includes at least one of the aforementioned batteries. This can be a battery pack consisting of at least one of the aforementioned batteries combined with conventional batteries, or a battery pack consisting of at least two or more of the aforementioned batteries. These batteries, as individual units, are connected to form the battery pack. These batteries can be electrically connected using methods conventional in the art, such as series connection, parallel connection, or a hybrid connection including both of these methods, without particular limitation.

[0086] The sixth aspect of the present invention provides an electrical device comprising a composite nylon material of the first aspect, or a composite nylon material prepared by the preparation method of the second aspect, or an aluminum-plastic film of the third aspect, or a battery of the fourth aspect, or a battery pack of the fifth aspect. Therefore, the electrical device has a long service life and high safety.

[0087] This invention does not impose any special limitation on the specific types of electrical equipment, and can be any conventional electrical equipment in the field, such as power equipment (e.g., electric vehicles, electric cars), electronic equipment (e.g., mobile phones, tablets, laptops, digital cameras, etc.), wearable devices (e.g., watches, bracelets, VR glasses, etc.), energy storage power stations, etc., without any particular limitation.

[0088] The following detailed description of the composite nylon material, aluminum-plastic film, and battery including the composite nylon material provided by the present invention will be provided through specific embodiments.

[0089] Example 1

[0090] 1) Preparation of composite nylon material. Inorganic filler (specifically silica) and coupling agent (specifically KH500) are uniformly dispersed in anhydrous ethanol at a mass ratio of 100:1. After drying and sieving, a dispersant (specifically polypolyol) is added, with a silica:polypolyol mass ratio of 1:40. Deionized water is added, and the mixture is subjected to high-speed stirring, shearing, emulsification, and vacuum degassing to remove the solvent, yielding a mixture of filler and dispersant. Nylon (specifically polycaprolactam) is sliced ​​and mixed uniformly according to the mass ratio of nylon:filler and dispersant mixture:antioxidant (specifically butylated hydroxytoluene):lubricant (specifically stearic acid):nucleating agent (specifically talc) = 58:41:0.2:0.2:0.6. The mixture is then vacuum dried, melt-plasticized at 200℃~300℃, and extruded through a T-die to form a cast sheet, obtaining the composite nylon material.

[0091] 2) Preparation of the composite nylon layer. First, the composite nylon material is longitudinally stretched at 90℃ and 15m / min, with a stretch ratio of 3. Then, it is transversely stretched at 105℃ and 15m / min, with a stretch ratio of 3, to obtain a stretched nylon film. The stretched film is then heat-treated at 180℃ for 30s and cooled at 10m / s. Finally, the film is subjected to corona treatment at 2kW power and 30m / min to obtain the composite nylon layer.

[0092] 3) Preparation of aluminum-plastic film

[0093] 3.1) Aluminum foil pretreatment. The aluminum foil was washed sequentially with 5wt% NaOH solution, 15wt% dilute nitric acid solution and pure water to remove foreign matter from the aluminum foil surface. Then, the aluminum foil was treated with acidic chromate (specifically, CrO3:NaF:H3PO4 mass ratio = 10:1:4) to form a passivation layer on the aluminum foil surface, thus obtaining passivated aluminum foil.

[0094] 3.2) Coating the nylon film layer. A two-component polyurethane (main agent: hydroxy acrylate, curing agent: isocyanate, mass ratio of 1.3:1) was prepared as an adhesive. The adhesive was applied to the passivated aluminum foil using a coating machine, and the nylon film layer was bonded to the passivated aluminum foil through a dry lamination process and the adhesive.

[0095] 3.3) Adhesive polymer layer (specifically polypropylene layer). Using a multi-layer co-extrusion coating process, the acidic polypropylene layer and the multi-layer polypropylene layer are co-extruded, and one side of the acidic polypropylene layer is coated onto the aluminum foil surface, so that the multi-layer polypropylene layer adheres to the passivated aluminum foil.

[0096] 3.4) Curing treatment. Curing at 30℃ for 30 hours yields aluminum-plastic film.

[0097] Example 2

[0098] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 1), the mass ratio of silica to polyol in the mixture of filler and dispersant is 5:30, and the mass ratio of nylon to mixture of filler and dispersant to antioxidant to lubricant to nucleating agent is 64:35:0.2:0.2:0.6.

[0099] Example 3

[0100] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 1), the mass ratio of silica to polyol in the mixture of filler and dispersant is 9:20, and the mass ratio of nylon to the mixture of filler and dispersant to antioxidant to lubricant to nucleating agent is 70:29:0.2:0.2:0.6.

[0101] Example 4

[0102] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 1), the mass ratio of silica to polyol in the mixture of filler and dispersant is 11:10, and the mass ratio of nylon to mixture of filler and dispersant to antioxidant to lubricant to nucleating agent is 78:21:0.2:0.2:0.6.

[0103] Example 5

[0104] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 1), the mass ratio of silica to polyol in the mixture of filler and dispersant is 0.5:40.5, and the mass ratio of nylon to the mixture of filler and dispersant to antioxidant to lubricant to nucleating agent is 58:41:0.2:0.2:0.6.

[0105] Example 6

[0106] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 1), 60g of biodegradable filler (specifically, linear corn starch) is uniformly dispersed in 40g of deionized water, 12g of acetic anhydride and 6g of concentrated sulfuric acid with a concentration of 1mol / L are added, and the mixture is stirred and mixed for 5h. After washing until neutral, a dispersant (specifically, a polypolyol) is added, with a linear corn starch:polypolyol mass ratio of 3:40. The solvent is removed to obtain a mixture of filler and dispersant. Then, nylon (specifically, polycaprolactam) is sliced ​​and mixed according to the mass ratio of nylon:mixture of filler and dispersant:antioxidant (specifically, butylated hydroxytoluene):lubricant (specifically, stearic acid):nucleating agent (specifically, talc) = 56:43:0.2:0.2:0.6.

[0107] Example 7

[0108] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 6. The difference is that in step 1), the mass ratio of linear corn starch to polyol in the mixture of filler and dispersant is 5:35, and the mass ratio of nylon to mixture of filler and dispersant to antioxidant to lubricant to nucleating agent is 59:40:0.2:0.2:0.6.

[0109] Example 8

[0110] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 6. The difference is that in step 1), the mass ratio of linear corn starch to polyol in the mixture of filler and dispersant is 30:20, and the mass ratio of nylon to mixture of filler and dispersant to antioxidant to lubricant to nucleating agent is 49:50:0.2:0.2:0.6.

[0111] Example 9

[0112] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 6. The difference is that in step 1), the mass ratio of linear corn starch to polyol in the mixture of filler and dispersant is 35:10, and the mass ratio of nylon to mixture of filler and dispersant to antioxidant to lubricant to nucleating agent is 54:45:0.2:0.2:0.6.

[0113] Example 10

[0114] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in embodiment 1. The difference is that in step 2), the stretching ratio of the longitudinal stretching and transverse stretching of the composite nylon material is 4.2.

[0115] Example 11

[0116] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in embodiment 1. The difference is that in step 2), the stretching ratio of the longitudinal stretching and transverse stretching of the composite nylon material is 4.

[0117] Example 12

[0118] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in embodiment 1. The difference is that in step 2), the stretching ratio of the longitudinal stretching and transverse stretching of the composite nylon material is 2.

[0119] Example 13

[0120] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 3), the thickness of the aluminum foil is adjusted to 30 μm and the thickness of the polymer layer is adjusted to 20 μm.

[0121] Example 14

[0122] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 3), the thickness of the aluminum foil is adjusted to 50 μm and the thickness of the polymer layer is adjusted to 60 μm.

[0123] Example 15

[0124] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 1), silicon dioxide is replaced with titanium dioxide and the dispersant is replaced with polyurethane.

[0125] Example 16

[0126] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 1), silicon dioxide is replaced with zinc oxide and the dispersant is replaced with silicone oil.

[0127] Example 17

[0128] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in embodiment 6. The difference is that in step 1), the straight-chain corn starch is replaced with straight-chain potato starch and the dispersant is replaced with ethylene glycol.

[0129] Example 18

[0130] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in embodiment 6. The difference is that in step 1), the linear corn starch is replaced with linear sweet potato starch and the dispersant is replaced with isopropanol.

[0131] Comparative Example 1

[0132] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that no inorganic filler is prepared, and the aluminum-plastic film is made directly from nylon (specifically polycaprolactam) slices.

[0133] Comparative Example 2

[0134] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1. The difference is that in step 1), the mass ratio of silica to polyol in the mixture of filler and dispersant is 30:50, and the mass ratio of nylon to mixture of filler and dispersant to antioxidant to lubricant to nucleating agent is 19:80:0.2:0.2:0.6.

[0135] Comparative Example 3

[0136] The preparation method of the aluminum-plastic film in this embodiment is basically the same as that in Example 1, except that in step 1), the dispersant is changed to sodium dodecyl sulfate.

[0137] Test case

[0138] Using lithium iron phosphate as the positive electrode, graphite as the negative electrode, an NP ratio of 1.1, an E / PP membrane as the ion exchange membrane, and LiPF6 as the electrolyte, a 7+8 layer stacked battery was assembled, with 7 layers of positive electrode and 8 layers of negative electrode. The aluminum-plastic film prepared in the examples and comparative examples was used as the shell to assemble a soft-pack battery.

[0139] (I) Physical property testing

[0140] 1. Percentage of inorganic fillers, biodegradable materials, and dispersants by mass in composite nylon materials.

[0141] After uniformly heating the surface of the nylon layer and the interface between the nylon and aluminum foil layers for 3 minutes using a hair dryer on high heat, the nylon layer was peeled off from the aluminum foil layer. A 1.5cm diameter nylon disc was obtained by sampling with a φ1.5cm sampler. This nylon disc was then quantitatively characterized using an infrared spectrometer (Avatar 360FITR Fourier transform infrared spectrometer) to obtain an infrared spectrum. The spectrum is shown at 1100cm. -1 The absorption peaks around 3500-3000 cm⁻¹ are stretching vibration peaks of the Si-O-Si group, which can characterize SiO₂ in fluids; -1 The absorption peaks around 2920 cm⁻¹ are stretching vibration peaks of the -OH group. -1 The left and right sides are the vibrational peaks of CH, which can be used to jointly characterize starch; 1680-1650 cm⁻¹ -1 The absorption band at 670 cm⁻¹ is a characteristic absorption peak of the unsaturated C=O bond in NH₃CO (amide), which can characterize nylon. The peak area is obtained by integrating the corresponding absorption bands. Based on the ratio of the characteristic peak areas mentioned above, the content of SiO₂, starch, and nylon (polyamide) in the outer layer of nylon can be determined. The content of other fillers, such as TiO₂ at 670 cm⁻¹, can also be confirmed using a similar method. -1 There is a Ti-O absorption peak, and Al2O3 has an absorption peak at 640 cm⁻¹. -1 There is an Al-O absorption peak, and ZnO has an absorption peak at 540 cm⁻¹. -1 There is a Zn-O absorption peak, and CaCO3 has an absorption peak at 1420 cm⁻¹. -1 There is CO3 2- Absorption peak. Alcohols show an absorption peak at 3450 cm⁻¹. -1 There is a broad OH absorption peak; polyurethane shows an absorption peak at 3320 cm⁻¹. -1 and 1705cm -1 It exhibits absorption peaks for NH and CO; polydimethylsiloxane shows an absorption peak at 2960 cm⁻¹. -1 and 1080cm -1 It exhibits absorption peaks for CH3 and Si-O-Si.

[0142] 2. Critical shear rate and viscosity increase of composite nylon materials

[0143] After uniformly heating the surface of the nylon layer and the interface between the nylon and aluminum foil layers for 3 minutes using a hair dryer on high heat, the nylon layer was peeled off from the aluminum foil layer. The resulting nylon layer was pulverized into nylon particles of approximately 1 mm using a liquid nitrogen cryogenic ball mill (YDQM-60). A solution was prepared according to the mass ratio of nylon particles:KH500:ethanol = 40:0.1:59.9. The resulting solution was dispersed in an ultrasonic homogenizer (VCX750) for 30 minutes, and then defoamed in an inert atmosphere to obtain a fluid solution. This fluid solution was then placed on the rotating rheometer (RS-CPS) turntable to test its rheological curve, with a shear rate set to 0.01 s⁻¹. -1 -1500s -1 The shear rate at which viscosity increases nonlinearly is the critical shear rate, and the viscosity at this point is η0. The highest viscosity value on the rheological curve is taken as the maximum viscosity η. max Viscosity increase = (η) max -η0) / η0.

[0144] 3. Thickness of the composite nylon layer, aluminum foil, and polymer layer

[0145] The aluminum-plastic film was cut into 2cm × 1cm samples and treated with a CP ion polisher (IB-19510) to expose the cross-section. The ion beam energy was set to 5kV and the polishing speed was set to 500μm / h. The cross-section was then placed in a SEM (FlexSEM1000) and the thickness of different layers of the aluminum-plastic film was measured using the SEM scale to obtain the thickness of the composite nylon layer, aluminum foil, and polymer layer.

[0146] The test results are detailed in Table 1.

[0147] Table 1

[0148]

[0149]

[0150] (II) Mechanical and Electrochemical Performance Testing

[0151] 1. Peel force of composite nylon layer

[0152] Cut the aluminum-plastic film into 25cm×10cm samples. Apply adhesive to the nylon layer of the aluminum-plastic film. Fold the free end of the adhesive layer back 180° and clamp it into the upper clamp. Fix the other side of the substrate to the lower clamp. Fix the clamp on the universal testing machine (Instron 5965). Pull the tape on the nylon layer and peel the nylon layer off the aluminum-plastic film at a 180° angle. The peeling speed is 500mm / min, and the effective peeling length is ≥100mm. Record the maximum peeling force.

[0153] 2. Low temperature stability test

[0154] The aluminum-plastic film was cut into 25cm × 10cm samples, and the maximum puncture force of the samples at 25℃ was tested. The samples were then stored in a -30℃ oven for 24 hours, and the maximum puncture force of the samples was tested again. Multiple tests were performed, and the average value was taken.

[0155] The maximum puncture force test was performed using a universal testing machine (Instron 5965). The specific operation was as follows: the aluminum-plastic film was cut into 10cm×10cm samples, the aluminum-plastic film was fixed in the fixture, the aluminum-plastic film was perpendicular to the needle, the polymer layer was facing the puncture needle, a needle with a punch diameter of 1mm was selected and pressed vertically at a speed of 50mm / min until the needle completely penetrated the aluminum-plastic film, the puncture pressure curve was collected, and the peak value of the curve was recorded as the maximum puncture force.

[0156] 3. Drop test

[0157] Place a fully charged pouch cell on a cell drop tester (GX-6052), with all six sides of the cell facing the ground, and drop it vertically from a height of 1.2m six times. After the six drops, let it stand for 1 hour. Record the initial state and the battery voltage and DC impedance ACR after standing for 1 hour. Calculate the voltage difference and ACR change rate of the battery after the drop test and observe whether there is any leakage or fire in the cell.

[0158] The performance test results are detailed in Table 2.

[0159] Table 2

[0160]

[0161]

[0162] Based on the above analysis, it can be seen that the experimental examples in this invention have better puncture resistance and drop resistance compared to the comparative examples, which can effectively improve the safety of the battery.

[0163] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite nylon material, characterized in that, The composite nylon material comprises filler and nylon; the critical shear rate of the composite nylon material is 1 s. -1 -1200s -1 The viscosity increase of the composite nylon material is greater than 0.

2. The composite nylon material according to claim 1, characterized in that, The viscosity increase of the composite nylon material is 5-600, preferably 50-600; And / or, the critical shear rate of the composite nylon material is 1 s. -1 -1000s -1 .

3. The composite nylon material according to claim 1 or 2, characterized in that, The packing material includes at least one of inorganic packing material and biodegradable packing material.

4. The composite nylon material according to claim 3, characterized in that, The filler surface contains at least one of amino, carboxyl, epoxy, isocyanate, amide, siloxane, long-chain alkyl, quaternary ammonium salt, and phosphate ester groups, preferably amino and / or epoxy.

5. The composite nylon material according to claim 3 or 4, characterized in that, The inorganic filler includes at least one of silicon dioxide, titanium dioxide, aluminum oxide, zinc oxide, calcium carbonate, and magnesium calcium carbonate. And / or, the biodegradable filler includes at least one of corn starch, potato starch, and sweet potato starch.

6. The composite nylon material according to claim 3 or 4, characterized in that, When the filler includes the inorganic filler, the inorganic filler accounts for 0.5wt%-11wt% of the mass percentage of the composite nylon material, preferably 1wt%-11wt%. When the filler includes the biodegradable filler, the biodegradable filler accounts for 3wt%-35wt% of the mass percentage of the composite nylon material, preferably 5wt%-35wt%.

7. The composite nylon material according to any one of claims 1-6, characterized in that, The composite nylon material also includes a dispersant, which accounts for 10wt%-40wt% of the mass of the composite nylon material.

8. The composite nylon material according to any one of claims 1-7, characterized in that, The dispersant includes at least one of polyols, polyurethanes, polydimethylsiloxanes, silicone oils, ethanol, isopropanols, ethylene glycol, and mineral oils.

9. The composite nylon material according to any one of claims 1-8, characterized in that, The nylon includes at least one of polycaprolactam, polyhexamethylene adipamide, polydecanolactam, polyundecanolactam, polydodecanolactam, polyhexamethylene adipamide, polydodecanoylhexamethylene adipamide, polyhexamethylene terephthalamide, polynonyl terephthalamide, and polydecanoyl terephthalamide.

10. A method for preparing the composite nylon material according to any one of claims 1-9, characterized in that, Includes the following steps: Nylon and filler are mixed to obtain a mixture, which is then melted and shaped to obtain a composite nylon material.

11. The method for preparing the composite nylon material according to claim 10, characterized in that, Before mixing the nylon and filler to obtain the mixture, the filler and dispersant are mixed first.

12. An aluminum-plastic film, characterized in that, It includes an aluminum foil and a composite nylon layer disposed on one side of the aluminum foil, wherein the composite nylon layer comprises the composite nylon material according to any one of claims 1-9 or the composite nylon material prepared by the preparation method according to claim 10 or 11.

13. The aluminum-plastic film according to claim 12, characterized in that, The aluminum-plastic film meets any of the following conditions: The thickness of the aluminum foil is 30μm-50μm; The thickness of the composite nylon layer is 8μm-30μm, preferably 10μm-30μm.

14. The aluminum-plastic film according to claim 12 or 13, characterized in that, The aluminum-plastic film also includes a polymer layer, which is disposed on the other side of the aluminum foil.

15. The aluminum-plastic film according to claim 14, characterized in that, The polymer layer includes at least one of polypropylene and polyethylene; And / or, the thickness of the polymer layer is 20μm-60μm.

16. The aluminum-plastic film according to any one of claims 12-15, characterized in that, The peel strength of the composite nylon layer is 5N / cm-8N / cm.

17. A battery, characterized in that, Includes the composite nylon material according to any one of claims 1-9, or the composite nylon material prepared by the preparation method according to claim 10 or 11, or the aluminum-plastic film according to any one of claims 12-16.

18. A battery pack, characterized in that, Includes the composite nylon material according to any one of claims 1-9, or the composite nylon material prepared by the preparation method according to claim 10 or 11, or the aluminum-plastic film according to any one of claims 12-16, or the battery according to claim 17.

19. An electrical appliance, characterized in that, This includes the composite nylon material according to any one of claims 1-9, or the composite nylon material prepared by the preparation method according to claim 10 or 11, or the aluminum-plastic film according to any one of claims 12-16, or the battery according to claim 17, or the battery pack according to claim 18.

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