Composite copper foil current collector for aviation battery resistant to extreme temperature range and battery

Abstract

The invention discloses a composite copper foil current collector for an extreme temperature range resistant aviation battery and a battery, and relates to the technical field of batteries. Through the multi-layer structural design of the composite copper foil, the modified PI film is used as a base film, the composite copper foil has excellent extreme temperature range resistance and embrittlement and softening resistance by virtue of the synergistic effect of fluorine-containing groups and TiAlC, and the thermal expansion and cold contraction stress at the extreme temperature is further counteracted in cooperation with the structural buffering of the edge dovetail laser micro-carving grooves, so that the service life of the composite copper foil is prolonged, and the service life of the composite copper foil is prolonged. The performance failure of the traditional current collector at high and low temperatures is avoided; and meanwhile, the stress dispersion design of the dovetail grooves is combined, so that the rate capability and the cycle performance of the battery prepared from the composite copper foil current collector are remarkably improved, and the dual requirements of aviation scenes on extreme temperature range adaptability and mechanical stability are comprehensively met.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of batteries, in particular to a composite copper foil current collector for an aviation battery resistant to extreme temperature domains and a battery. BACKGROUND

[0002] In the past two years, domestic aviation aircraft have ushered in an opportunity for vigorous development, and as an indispensable component of aircraft equipment, the use environment of the battery is particularly harsh. The temperature range required by the aircraft battery is wide, covering -60 DEG C to 70 DEG C, and during takeoff and landing, the equipment and the battery will continuously receive impact, which makes the performance requirements of the aviation battery much higher than those of the conventional battery.

[0003] However, in the prior art, the traditional aluminum foil and copper foil current collector used in conventional batteries has the problems of high rigidity and large density, is prone to brittle fracture at -60 DEG C and softening at +70 DEG C, and is difficult to meet the requirements of cold and hot impact and vibration and impact in the aviation scene; although the existing PET and PP-based composite copper foil is light, PET will appear brittle at a temperature lower than -40 DEG C, and PP will creep at a temperature higher than 60 DEG C, and neither of them can cover the wide temperature domain of aviation. At the same time, the traditional current collector uses pure aluminum foil and copper foil, and the material thickness and surface density are large, resulting in a heavy weight of the entire battery cell; the PET and PP used in the existing composite copper foil have low elastic modulus and are prone to brittle or softening at extreme temperature domains, and the material elongation rate is low, the impact resistance is poor, and it is difficult to meet the use requirements of the aviation battery.

[0004] In summary, it is of great significance to solve the above problems and prepare a composite copper foil current collector for an aviation battery resistant to extreme temperature domains and a battery. SUMMARY

[0005] The application aims to provide a composite copper foil current collector for an aviation battery resistant to extreme temperature domains and a battery to solve the problems in the background art.

[0006] In order to solve the above technical problems, the application provides the following technical scheme: A composite copper foil current collector for an aviation battery resistant to extreme temperature domains, the composite copper foil current collector comprising a high-molecular-based film; the high-molecular-based film is provided with a Cu seed layer, an electroplated Cu thickening layer and an in-line coated conductive carbon-PI transition layer in sequence on both sides. More preferably, the high-molecular-based film is a modified PI film with a thickness of 3-20 mu m; the Cu seed layer further comprises nickel-chromium elements, the thickness of the seed layer is 20-30 nm, and the thickness of the Cu thickening layer is 0.2-1.0 mu m; the thickness of the conductive carbon-PI transition layer is 0.2-0.5 mu m.

[0007] More preferably, the preparation method of the modified PI film is: step 1: under a nitrogen atmosphere, 4,4'-(hexafluoroisopropyl) bis(p-phenoxy) diphenylamine is added to a tetrahydrofuran-dimethylacetamide mixed solution, stirred uniformly, and an amino-terminated polydimethylsiloxane solution is added and mixed uniformly; the temperature is set to 0-4℃, hexafluorodianhydride is slowly added, stirred for 24-30h, and a fluorine-containing solution is obtained; Step 2: under a nitrogen atmosphere, lithium fluoride is added to hydrochloric acid, stirred until completely dissolved, Ti3AlC2 powder is added, the temperature is set to 40-50℃, and stirred for 10-15h; water washing is performed until the supernatant pH is 5-6, freeze-drying is performed, the product is added to dimethylacetamide, polyvinylpyrrolidone is added, and ultrasonic dispersion is performed to obtain a Ti3AlC2 solution; Step 3: the fluorine-containing solution and the Ti3AlC2 solution are ultrasonically stirred at low temperature for 5-8h, filtered to obtain a solution; then the solution is spin-coated onto a glass sheet, pre-solidified, then a 3-(methacryloyloxy) propyl trimethoxysilane solution is sprayed on the surface, heat treatment is performed at a temperature of 70-80℃ for 30-40min, and stepwise heating is performed to obtain a modified PI film.

[0008] More preferably, in the raw materials of the fluorine-containing solution, by mass fraction: 10-20 parts of 4,4'-(hexafluoroisopropyl) bis(p-phenoxy) diphenylamine, 80-100 parts of a tetrahydrofuran-dimethylacetamide mixed solution, 2-4 parts of an amino-terminated polydimethylsiloxane solution, and 15-20 parts of hexafluorodianhydride; In the raw materials of the Ti3AlC2 solution, by mass fraction: 0.1-0.5 parts of lithium fluoride, 10-20 parts of hydrochloric acid, 0.5-1 parts of Ti3AlC2 powder, 3-4 parts of dimethylacetamide, and 0.01-0.05 parts of polyvinylpyrrolidone; In the raw materials of the modified PI film, the volume ratio of the fluorine-containing solution to the Ti3AlC2 solution is (5-10):1; the volume ratio of the Ti3AlC2 solution to the 3-(methacryloyloxy) propyl trimethoxysilane solution is 1:(0.1-0.3).

[0009] More preferably, in step 3, the pre-solidification temperature is 60-70℃, and the time is 3-5h; the stepwise heating process parameters are: the temperature is raised to 180-200℃ at a rate of 0.5-1.0℃ per minute, and maintained for 2-3h.

[0010] More preferably, the composite copper foil current collector edge uses continuous nanosecond laser to etch "dovetail" laser microgrooves; the process parameters of the continuous nanosecond laser are: cavity gas pressure is 40-60MPa, laser wavelength is 1000-1100nm, laser spot radius is 300-400μm, and laser power density is 100-150kW / cm 2The continuous laser irradiation time is 300-400 ms.

[0011] A battery prepared from a composite copper foil current collector for an aviation battery resistant to an extreme temperature range, and a preparation method of the battery is: Step 1: uniformly stirring and coating a positive active material on the composite copper foil current collector, setting the temperature to 120-150 DEG C, and vacuum drying to obtain a positive electrode sheet; Step 2: uniformly stirring and coating a negative active material on the metal sodium sheet, setting the temperature to 120-150 DEG C, and vacuum drying to obtain a negative electrode sheet; Step 3: assembling the battery in the following order in an argon-filled glove box: battery shell - placing the positive electrode sheet - adding electrolyte - placing the separator - adding electrolyte - placing the negative electrode sheet - placing the gasket spring - battery shell.

[0012] More preferably, the positive active material comprises NCM811 wrapped with gas-phase SiO2, the negative active material comprises a graphite-soft carbon composite, the battery shell comprises an embedded honeycomb aluminum reinforcing rib aluminum plastic film, and the separator comprises a PE double-sided ceramic separator.

[0013] More preferably, the electrolyte is composed of EC, EMC, DMC, PS and LiBF4, wherein the volume ratio of EC, EMC, DMC, PS and LiBF4 is (19-20):(19-20):(58-59):2:1.

[0014] Compared with the prior art, the present application has the following beneficial effects: The present application uses a modified PI film as a base film through the multi-layer structure design of the composite copper foil, which has excellent resistance to extreme temperature range performance, resists embrittlement and softening, and cooperates with the structure buffer of the edge "dovetail" laser micro-etching groove, further offsets the thermal expansion and cold shrinkage stress under extreme temperature, avoids the performance failure of the traditional current collector under high and low temperature; at the same time, the stress dispersion design of the dovetail groove significantly improves the rate performance and cycle performance of the battery prepared from the composite copper foil current collector, and fully meets the dual requirements of extreme temperature range adaptability and mechanical stability in aviation scenarios.

[0015] (1) The application adopts modified PI film as a polymer base film, introduces fluorine-containing groups into the main chain, side chains grafts siloxane segments and composite Ti3AlC2 nanomaterials, which significantly widens the temperature resistance range of the current collector, reduces the intermolecular force by using the strong electronegativity and steric hindrance effect of fluorine elements, and improves the high and low temperature resistance of the film; the amino-terminated polydimethylsiloxane improves the brittleness of the PI material through the "cushioning effect" of the flexible chain segment, and improves the impact resistance and brittle fracture resistance of the material at extreme temperatures; the Ti3AlC2 is uniformly dispersed after being treated by lithium fluoride and hydrochloric acid, and the excellent thermal conductivity and mechanical strength of the Ti3AlC2 itself enhance the overall rigidity and tensile properties of the film, improve the heat conduction efficiency of the base film, and avoid softening caused by local overheating; and 3-(methacryloyloxy) propyl trimethoxysilane is sprayed on the surface of the PI film, a covalent bond is formed by the reaction of the siloxane bond and the hydroxyl group on the surface of the PI, active groups are constructed on the surface of the film, the adhesion of the subsequent sputtered Cu seed layer and the electroplated Cu thickening layer is significantly improved, and the problem of peeling of the metal layer from the base film in the extreme temperature cold and hot cycle is avoided. (2) The dovetail structure of the edge of the current collector obtained by the application can disperse the stress received by the composite copper foil current collector in the vibration and impact process, avoid edge cracking or delamination caused by stress concentration, increase the conductive area of the edge of the current collector, guide the current along the groove body, reduce the contact resistance of the current collector, and improve the electrochemical performance stability of the battery at extreme temperature. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is the surface electron microscope graph of the composite copper foil current collector of the application.

[0017] Figure 2 It is the cross-section electron microscope graph of the composite copper foil current collector of the application.

[0018] Figure 3 It is the electron microscope graph of the "dovetail" laser micro-etching groove of the application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the application, not all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the application.

[0020] The following embodiments are parts by mass; it should be noted that there is no special restriction on the purchase manufacturer of all raw materials involved in the present application, which exemplarily includes: 4,4'-(hexafluoroisopropyl) bis (p-phenoxy) diphenylamine (CAS: 69563-88-8), amino-terminated polydimethylsiloxane (CAS: 106214-84-0), Ti3AlC2 powder (CAS: 196506-01-1), and other raw materials not specifically mentioned are commercially available.

[0021] Example 1: A preparation method of a composite copper foil current collector and a battery for an aviation battery resistant to an extreme temperature range, comprising the following steps: I. Preparation of modified PI film: Step 1: Under a nitrogen atmosphere, 10 parts of 4,4'-(hexafluoroisopropyl) bis (p-phenoxy) diphenylamine is added to 80 parts of a tetrahydrofuran-dimethylacetamide mixed solution (40 parts of tetrahydrofuran, 40 parts of dimethylacetamide), stirred uniformly, and 2 parts of an amino-terminated polydimethylsiloxane solution is added and mixed uniformly; the temperature is set to 2°C, 15 parts of hexafluoro dianhydride is slowly added, stirred for 24h, and a fluorine-containing solution is obtained; Step 2: Under a nitrogen atmosphere, 0.1 parts of lithium fluoride is added to 10 parts of hydrochloric acid, stirred until completely dissolved, 0.5 parts of Ti3AlC2 powder is added, the temperature is set to 40°C, and stirred for 10h; water washing is performed until the supernatant pH is 5, freeze-drying is performed, 3 parts of dimethylacetamide is added, 0.01 parts of polyvinylpyrrolidone is added, and ultrasonic dispersion is performed to obtain a Ti3AlC2 solution; Step 3: The fluorine-containing solution and the Ti3AlC2 solution are ultrasonically stirred at low temperature for 5h, filtered to obtain a solution; then the solution is spin-coated onto a glass sheet, the temperature is set to 60°C, and pre-curing is performed for 3h; then a 3-(methacryloyloxy) propyl trimethoxysilane solution is sprayed on the surface, the temperature is set to 70°C for heat treatment for 30min, the temperature is increased to 200°C at a rate of 0.5°C per minute, and maintained for 3h to obtain a modified PI film.

[0022] II. Preparation of a composite copper foil current collector: Cu seed layers, Cu thickening layers, and conductive carbon-PI transition layers are sputtered on both sides of the modified PI film in sequence, dried, and then a continuous nanosecond laser is used to etch "dovetail" laser microgrooves on the edges of the composite copper foil current collector; the parameters of the continuous nanosecond laser are as follows: cavity gas pressure is 50MPa, laser wavelength is 1064nm, laser spot radius is 400μm, laser power density is 120kW / cm 2 , and continuous laser irradiation time is 400ms to obtain a composite copper foil current collector.

[0023] III. Assembly to prepare a battery: Step 1: uniformly stir and coat the fumed SiO2-coated NCM811 on the composite copper foil current collector, set the temperature to 150℃, and vacuum dry to obtain a positive electrode sheet; Step 2: uniformly stir and coat the graphite-soft carbon composite on the metal sodium sheet, set the temperature to 150℃, and vacuum dry to obtain a negative electrode sheet; Step 3: (1) mix EC, EMC, DMC, PS, and LiBF4 in a volume ratio of 20:20:60:2:1 to configure an electrolyte; (2) in an argon-filled glove box, assemble a battery in the following order: fill the battery shell with a honeycomb aluminum reinforcing rib aluminum plastic film, place the positive electrode sheet, drop the electrolyte, place the PE double-sided ceramic separator, drop the electrolyte, place the negative electrode sheet, place the gasket spring, and the battery shell.

[0024] In this embodiment, the volume ratio of the fluorine-containing solution, Ti3AlC2 solution, and 3-(methacryloyloxy)propyl trimethoxysilane solution in the raw material of the modified PI film is 5:1:0.1; the thickness of the modified PI film is 3μm, the thickness of the Cu seed layer is 20nm, the thickness of the Cu thickening layer is 0.2μm, and the thickness of the conductive carbon-PI transition layer is 0.2μm.

[0025] Embodiment 2: A preparation method of a composite copper foil current collector and a battery for an extreme temperature range aviation battery, comprising the following steps: I. Preparation of modified PI film: Step 1: Under a nitrogen atmosphere, add 15 parts of 4,4'-(hexafluoroisopropyl) bis(p-phenoxy) diphenylamine to a 90 part tetrahydrofuran-dimethylacetamide mixed solution (45 parts tetrahydrofuran, 45 parts dimethylacetamide), stir uniformly, and add 3 parts of amino-terminated polydimethylsiloxane solution and mix uniformly; set the temperature to 2℃, slowly add 17 parts of hexafluoro dianhydride, stir for 27h, and obtain a fluorine-containing solution; Step 2: Under a nitrogen atmosphere, add 0.3 parts of lithium fluoride to 15 parts of hydrochloric acid, stir until completely dissolved, add 0.7 parts of Ti3AlC2 powder, set the temperature to 45℃, stir for 12h, wash with water until the supernatant pH is 5.5, freeze-dry, add to 3.5 parts of dimethylacetamide, add 0.03 parts of polyvinylpyrrolidone, and ultrasonic dispersion to obtain a Ti3AlC2 solution; Step 3: low-temperature ultrasonic stir the fluorine-containing solution and Ti3AlC2 solution for 7h, filter to obtain a solution; then spin coat it onto a glass sheet, set the temperature to 65℃, and pre-cure for 4h; then spray 3-(methacryloyloxy) propyl trimethoxysilane solution on the surface, set the temperature to 75℃ for heat treatment for 35min, increase the temperature to 200℃ at a rate of 0.5℃ per minute, and maintain for 3h to obtain a modified PI film.

[0026] II. Preparation of composite copper foil current collector: sputtering Cu seed layer, electroplating Cu thickening layer, and in-line coating conductive carbon-PI transition layer on both sides of the modified PI film in sequence, and then drying, and then using continuous nanosecond laser to etch a "dovetail" laser microgroove on the edge of the composite copper foil current collector, the parameters of the continuous nanosecond laser being: cavity gas pressure 50 MPa, laser wavelength 1064 nm, laser spot radius 400 μm, laser power density 120 kW / cm 2 , and continuous laser irradiation time 400 ms, to obtain the composite copper foil current collector.

[0027] III. Assembling to prepare a battery: Step 1: uniformly stirring and coating the gas-phase SiO2-wrapped NCM811 on the composite copper foil current collector, setting the temperature to 150℃, and vacuum drying to obtain a positive electrode sheet; Step 2: uniformly stirring and coating the graphite-soft carbon composite on the metal sodium sheet, setting the temperature to 150℃, and vacuum drying to obtain a negative electrode sheet; Step 3: (1) mixing and configuring EC, EMC, DMC, PS, and LiBF4 in a volume ratio of 20:20:60:2:1 to obtain an electrolyte; (2) in an argon-filled glove box, assembling the battery in the following order: placing an inner-embedded honeycomb aluminum reinforced aluminum plastic film battery shell - placing the positive electrode sheet - adding the electrolyte - placing a PE double-sided ceramic separator - adding the electrolyte - placing the negative electrode sheet - placing a gasket spring - battery shell.

[0028] In this embodiment, in the raw material of the modified PI film, the fluorine-containing solution, the Ti3AlC2 solution, and the 3-(methacryloyloxy)propyl trimethoxysilane solution are in a volume ratio of 7:1:0.2; the thickness of the PI film is 6 μm, the thickness of the Cu seed layer is 25 nm, the thickness of the Cu thickening layer is 0.4 μm, and the thickness of the conductive carbon-PI transition layer is 0.3 μm.

[0029] Example 3: A preparation method of a composite copper foil current collector for an aerospace battery resistant to extreme temperature domains and a battery, comprising the following steps: I. Preparation of a modified PI film: Step 1: under a nitrogen atmosphere, adding 20 parts of 4,4'-(hexafluoroisopropyl) bis(p-phenoxy) diphenylamine to 100 parts of a tetrahydrofuran-dimethylacetamide mixed solution (50 parts of tetrahydrofuran and 50 parts of dimethylacetamide), stirring uniformly, and then adding 4 parts of an amino-terminated polydimethylsiloxane solution and mixing uniformly; setting the temperature to 2℃, slowly adding 20 parts of hexafluorodiphthalic anhydride, and stirring for 30 h to obtain a fluorine-containing solution; Step 2: Under a nitrogen atmosphere, 0.5 parts of lithium fluoride was added to 20 parts of hydrochloric acid, stirred until completely dissolved, 1 part of Ti3AlC2 powder was added, the temperature was set to 50℃, and stirred for 15h, washed with water until the supernatant pH was 6, freeze-dried, added to 4 parts of dimethylacetamide, 0.05 parts of polyvinylpyrrolidone was added, ultrasonic dispersion, to obtain a Ti3AlC2 solution; Step 3: The fluorine-containing solution and the Ti3AlC2 solution were ultrasonically stirred at low temperature for 8h, filtered to obtain a solution; then it was spin-coated onto a glass sheet, the temperature was set to 70℃, and pre-solidified for 5h; then a 3-(methacryloyloxy)propyl trimethoxysilane solution was sprayed on the surface, the temperature was set to 80℃ for heat treatment for 40min, the temperature was raised to 200℃ at a rate of 0.5℃ per minute, and maintained for 3h, to obtain a modified PI film.

[0030] II. Preparation of composite copper foil current collector: A Cu seed layer, a Cu thickening layer, and an in-line conductive carbon-PI transition layer were sputtered on both sides of the modified PI film in sequence, dried, and then a continuous nanosecond laser was used to etch a "dovetail" laser microgroove on the edge of the composite copper foil current collector. The parameters of the continuous nanosecond laser were as follows: cavity gas pressure was 50MPa, laser wavelength was 1064nm, laser spot radius was 400μm, laser power density was 120kW / cm 2 , and continuous laser irradiation time was 400ms, to obtain a composite copper foil current collector.

[0031] III. Assembly to prepare a battery: Step 1: The gas phase SiO2-coated NCM811 was stirred and uniformly coated on the composite copper foil current collector, the temperature was set to 150℃, and vacuum drying was performed to obtain a positive electrode sheet; Step 2: The graphite-soft carbon composite was stirred and uniformly coated on the metal sodium sheet, the temperature was set to 150℃, and vacuum drying was performed to obtain a negative electrode sheet; Step 3: (1) EC, EMC, DMC, PS, and LiBF4 were mixed in a volume ratio of 20:20:60:2:1 to configure an electrolyte; (2) In an argon-filled glove box, an embedded honeycomb aluminum reinforced aluminum plastic film battery case was placed, followed by the positive electrode sheet, dropwise addition of electrolyte, placement of a PE double-sided ceramic separator, dropwise addition of electrolyte, placement of the negative electrode sheet, placement of a gasket spring, and assembly of the battery case in the order of assembly, to obtain a battery.

[0032] In the present embodiment, the volume ratio of the fluorine-containing solution, the Ti3AlC2 solution, and the 3-(methacryloyloxy)propyl trimethoxysilane solution in the raw materials of the modified PI film was 10:1:0.3; the thickness of the modified PI film was 10μm, the thickness of the Cu seed layer was 30nm, the thickness of the Cu thickening layer was 1.0μm, and the thickness of the conductive carbon-PI transition layer was 0.5μm.

[0033] Comparative Example 1: Based on Example 2, adjust the composition of the modified PI film, do not add amino-terminated polydimethylsiloxane; the rest is the same as Example 2.

[0034] Comparative Example 2: Based on Example 2, adjust the composition of the modified PI film, do not add Ti3AlC2; the rest is the same as Example 2.

[0035] Comparative Example 3: Based on Example 2, the composite copper foil current collector does not undergo nanosecond laser etching "dovetail" laser micro-etching groove; the rest is the same as Example 2.

[0036] Comparative Example 4: Based on Example 2, use a conventional commercially available PI film to assemble the battery; the rest is the same as Example 2.

[0037] Detection experiment: The battery was subjected to charge-discharge test by using a battery charge-discharge tester to test the rate performance: the temperature was set to -60°C, 70°C; the voltage range was 2.8-4.2V, the rate discharge current was 0.5C, and the capacity retention rate was tested. The capacity retention rate of the button cell was tested by using a battery charge-discharge tester to test the cycle performance: the voltage range was 2.8-4.2V, the cycle number was 500 times, the discharge current was 1C, and the capacity retention rate was tested. The data obtained are shown in the following table:

[0038] Conclusion: From the data in the above table, it can be seen that the battery assembled by the composite copper foil current collector prepared by the modified PI film realizes excellent performance of the aviation battery in the extreme temperature range. Among them, the comprehensive performance of Example 2 is the best, and the 0.5C capacity retention rate and 500 cycle performance at -60°C and 70°C are significantly better than those of Examples 1 and 3.

[0039] Comparing example 2 with comparative examples 1-4, no amino-terminated polydimethylsiloxane is added, because the polydimethylsiloxane segment can reduce the glass transition temperature of the film and improve the mechanical stability at low temperature, thus leading to the decrease of the flexibility and low-temperature resistance of the modified PI film, making the film brittle at-60℃, leading to poor contact of the current collector interface; no Ti3AlC2 is added, because Ti3AlC2 acts as a conductive reinforcing phase, and its absence reduces the conductivity and thermal stability of the PI film, and the accumulation of heat at high temperature accelerates the decomposition of the electrolyte, while the insufficient conductivity increases the resistance of the current collector; leading to the decrease of the capacity retention rate and cycle performance; the lack of laser micro-etched " swallow-tail " groove reduces the interfacial adhesion between the copper layer and the PI film, making the copper layer easy to separate from the PI film due to thermal expansion and contraction during charge and discharge cycles, leading to a sharp increase in the interface resistance; using a conventional commercially available PI film, because it does not contain fluorine groups, Ti3AlC2 and silane modification, the high and low temperature resistance is poor and the interfacial compatibility with the copper layer is insufficient, at extreme temperatures, the structural stability of the film decreases, and the capacity retention rate and cycle performance decrease significantly. Therefore, by modifying the PI film, the composite copper foil current collector for extreme temperature aviation battery is prepared, and the battery prepared therefrom has excellent capacity retention rate and cycle stability.

[0040] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments but can be implemented in other embodiments without departing from the scope of the application. The embodiments are to be considered in all respects as being illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the description above, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A composite copper foil current collector for extreme temperature-resistant aviation batteries, characterized by: The composite copper foil current collector comprises a polymer base film; a Cu seed layer is sputtered on both sides of the polymer base film, a Cu thickening layer is electroplated, and a conductive carbon-PI transition layer is coated online; The polymer base film is a modified PI film with a thickness of 3~20μm; the Cu seed layer also includes nickel and chromium elements, the thickness of the seed layer is 20~30nm, the thickness of the Cu thickening layer is 0.2~1.0μm; the thickness of the conductive carbon-PI transition layer is 0.2~0.5μm.

2. The composite copper foil current collector for extreme temperature resistant aviation batteries according to claim 1, characterized in that: The preparation method of the modified PI film is: Step 1: Under a nitrogen atmosphere, add 4,4'-(hexafluoroisopropyl)bis(p-phenyloxy)diphenylamine to a tetrahydrofuran-dimethylacetamide mixed solution, stir evenly, add amino-terminated polydimethylsiloxane solution and mix evenly; set the temperature to 0-4°C, slowly add hexafluorodianhydride, and stir for 24-30 hours to obtain a fluorine-containing solution; Step 2: Under a nitrogen atmosphere, add lithium fluoride to hydrochloric acid and stir until completely dissolved. Add Ti3AlC2 powder, set the temperature to 40-50°C, stir for 10-15 hours, wash with water until the pH of the supernatant is 5-6, freeze-dry, add to dimethylacetamide, add polyvinylpyrrolidone, and ultrasonically disperse to obtain a Ti3AlC2 solution. Step 3: Ultrasonic stirring of the fluorine-containing solution and Ti3AlC2 solution at low temperature for 5-8 hours, filtering to obtain a solution; then spin coating it onto a glass slide, pre-curing it, and then spraying 3-(methacryloyloxy)propyltrimethoxysilane solution on its surface. Set the temperature to 70-80°C for heat treatment for 30-40 minutes, and perform step-by-step heating to obtain a modified PI film.

3. The composite copper foil current collector for extreme temperature resistant aviation batteries according to claim 2, characterized in that: The raw materials of the fluorine-containing solution are, by mass, 10 to 20 parts of 4,4'-(hexafluoroisopropyl)bis(p-phenyloxy)diphenylamine, 80 to 100 parts of a tetrahydrofuran-dimethylacetamide mixed solution, 2 to 4 parts of an amino-terminated polydimethylsiloxane solution, and 15 to 20 parts of hexafluorodianhydride; The raw materials of the Ti3AlC2 solution are, by mass, 0.1-0.5 parts of lithium fluoride, 10-20 parts of hydrochloric acid, 0.5-1 parts of Ti3AlC2 powder, 3-4 parts of dimethylacetamide, and 0.01-0.05 parts of polyvinylpyrrolidone; In the raw materials of the modified PI film, the volume ratio of the fluorine-containing solution and the Ti3AlC2 solution is (5-10):1; the volume ratio of the Ti3AlC2 solution and the 3-(methacryloyloxy)propyltrimethoxysilane solution is 1:(0.1-0.3).

4. The composite copper foil current collector for extreme temperature resistant aviation batteries according to claim 2, characterized in that: In step 3, the pre-curing temperature is 60-70°C and the time is 3-5 hours; the process parameters of the step heating are: heating to 180-200°C at a heating rate of 0.5-1.0°C per minute and maintaining for 2-3 hours.

5. The composite copper foil current collector for extreme temperature resistant aviation batteries according to any one of claims 1 to 4, characterized in that: The edge of the composite copper foil current collector is etched with a continuous nanosecond laser to form a "swallowtail" laser micro-groove. The process parameters of the continuous nanosecond laser are: cavity pressure of 40-60 MPa, laser wavelength of 1000-1100 nm, laser spot radius of 300-400 μm, and laser power density of 100-150 kW / cm 2 , the continuous laser irradiation time is 300~400ms.

6. The battery prepared by the composite copper foil current collector for extreme temperature resistant aviation battery according to claim 1, characterized in that: The preparation method of the battery is as follows: Step 1: Stir and evenly coat the positive electrode active material on the composite copper foil current collector, set the temperature to 120-150°C, and vacuum dry to obtain the positive electrode sheet; Step 2: Stir and evenly coat the negative active material on the sodium metal sheet, set the temperature to 120-150°C, and vacuum dry to obtain the negative electrode sheet; Step 3: In a glove box filled with argon, assemble the battery in the following order: battery shell - place the positive electrode - add electrolyte - place the diaphragm - add electrolyte - place the negative electrode - place the gasket spring - battery shell.

7. The battery prepared by the composite copper foil current collector for extreme temperature resistant aviation battery according to claim 6, characterized in that: The positive electrode active material includes NCM811 wrapped in gas-phase SiO2, the negative active material includes a graphite-soft carbon composite, the battery shell includes an aluminum-plastic film with embedded honeycomb aluminum reinforcement ribs, and the diaphragm includes a PE double-sided ceramic diaphragm.

8. The battery prepared by the composite copper foil current collector for extreme temperature resistant aviation battery according to claim 6, characterized in that: The electrolyte consists of EC, EMC, DMC, PS, and LiBF4, wherein the volume ratio of EC, EMC, DMC, PS, and LiBF4 is (19-20):(19-20):(58-59):2:1.

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