A high-rate cylindrical full-tab lithium ion battery and a preparation method thereof

Abstract

This invention discloses a high-rate cylindrical all-tab lithium-ion battery and its preparation method, belonging to the field of lithium-ion battery technology. The positive electrode of this battery adopts a composite system of bimodal particle size high-nickel ternary material and carbon nanotube-conductive carbon black to optimize lithium-ion diffusion and thermal conduction; the negative electrode adopts a composite system of mesophase carbon microspheres + third-generation silane-modified silicon-carbon + single-walled carbon nanotubes to suppress expansion and improve conductivity; the electrolyte contains multi-element high-temperature resistant additives to form a stable SEI film; an all-tab structure and multi-point welding of the current collector reduce internal resistance; and PVDF-based swelling tape compensates for cycle expansion. Through synergistic innovation in materials and structure, this invention solves the problem of balancing high rate, long cycle life, and safety in existing technologies, achieving a 14C discharge capacity retention rate ≥95% (80℃), an 8C cycle capacity decay ≤20% after 800 cycles, and a negative electrode expansion rate ≤15%. It can operate stably at -40℃ to 60℃, passes a 150% SOC overcharge test, and is suitable for high-end applications such as new energy vehicles and energy storage devices.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium ion batteries, and particularly relates to a high-rate cylindrical full-tab lithium ion battery and a preparation method thereof. BACKGROUND

[0002] Lithium ion batteries are widely used in various electronic devices, new energy vehicles and other fields due to their high energy density and long cycle life. With the expansion of application scenarios, the high-rate discharge performance of lithium ion batteries is increasingly required.

[0003] In the prior art, the rate type cylindrical lithium ion battery usually uses high nickel material as the positive electrode and silicon-doped graphite as the negative electrode to improve the energy density, and reduces the surface density to improve the rate performance. However, this kind of technology has obvious defects: the high nickel material has poor thermal stability, resulting in poor battery safety performance and short cycle life; the silicon-doped graphite negative electrode is prone to swelling effect during charging and discharging, and the battery temperature rises significantly during high-rate discharge, which seriously restricts the performance improvement and wide application of high-rate batteries. SUMMARY

[0004] In view of the deficiencies in the prior art, the purpose of the present application is to provide a high-rate cylindrical full-tab lithium ion battery and a preparation method thereof, which realizes stable operation of the battery in a wide temperature range, has excellent high-rate discharge performance, long cycle life and high safety performance, and solves the problems in the background art.

[0005] The application provides the following technical scheme: A high-rate cylindrical full-tab lithium ion battery comprises a positive electrode, a negative electrode, a separator, an electrolyte, a current collector and a termination tape; the positive electrode adopts a high nickel ternary material with a bimodal particle size distribution and a carbon nanotube-conductive carbon black composite conductive system; the negative electrode adopts a mesocarbon microbead and a third generation silane modified silicon-carbon composite system, and single-walled carbon nanotubes are added; the electrolyte is a high-temperature resistant electrolyte containing multiple additives; the current collector and the tab are laser pulse welded, and the termination tape is a PVDF-based swelling tape.

[0006] Preferably, the high nickel ternary material is LiNi x Co ᵧ Mn 1-x-y O2; wherein 0.8≤x≤0.95, 0.02≤y≤0.08, and the fine particles with a particle size of 2-4 μm are mixed with coarse particles with a particle size of 8-12 μm.

[0007] Preferably, the carbon nanotube content in the positive electrode is 0.4-1.5 wt%, the conductive carbon black content is 2.0-3.0 wt%, the positive electrode coating surface density is 250-270 g / m 2 , and the compaction density is 3.4-3.7 g / cm3 .

[0008] Preferably, the mass ratio of the mesophase carbon microbeads to the third generation silane-modified silicon carbon is 8.5-9.5:1, the single-walled carbon nanotube addition amount is 0.3-0.5wt%, and the negative electrode coating surface density is 8-13g / m 2 .

[0009] Preferably, the electrolyte uses LiPF6 as the main lithium salt, the concentration is 0.8-1.2mol / L, the solvent is a mixed solvent of ethylene carbonate, dimethyl carbonate and methyl ethyl carbonate, the mixing ratio is (1-3):(0.5-1.5):(6-8), and the additives include at least three of fluoroethylene carbonate, vinyl sulfate, 1,3-propane sulfone lactone and lithium bisfluorosulfonylimide.

[0010] Preferably, the fluoroethylene carbonate addition amount is 8-12wt%, the vinyl sulfate addition amount is 0.4-0.8wt%, and the lithium bisfluorosulfonylimide addition amount is 3-5wt%.

[0011] Preferably, the current collector includes a negative electrode copper-nickel composite current collector (thickness 0.15-0.25mm) and a positive electrode aluminum current collector (thickness 0.25-0.35mm); the initial thickness of the termination tape is 45-55μm, and the expansion at 180℃ is 120-140μm.

[0012] Preferably, a preparation method of a high-rate cylindrical full-tab lithium ion battery includes the following steps: S1: positive electrode sheet preparation: mixing high-nickel ternary material, carbon nanotubes, conductive carbon black, binder and additives with a solvent to prepare a positive electrode slurry, coating on an aluminum foil, drying and compacting, and reserving a tab area; S2: negative electrode sheet preparation: mixing mesophase carbon microbeads, third generation silane-modified silicon carbon, single-walled carbon nanotubes, thickening agent, conductive agent, binder and solvent to prepare a negative electrode slurry, coating on a copper foil, drying and compacting, and reserving a tab area; S3: preparation of a separator film: ceramic-coated separator film with polyethylene microporous film as the base film.

[0013] S4: electrolyte preparation: dissolving lithium salt in a mixed solvent and adding multiple additives, and stirring uniformly; S5: roll core preparation: winding the positive electrode sheet, the separator film and the negative electrode sheet to form a roll core, rubbing the tabs, welding the current collector and the tabs by laser pulse multi-point, and fixing the roll core by PVDF-based swelling tape; S6: battery assembly: assembling the roll core into a cylindrical steel shell, rolling, cap welding, baking, liquid injection, packaging, formation, and capacity distribution to obtain a finished battery.

[0014] Preferably, the binder in step S1 is polyvinylidene fluoride and the solvent is methylpyrrolidone; the thickener in step S2 is sodium carboxymethyl cellulose, the binder is styrene-butadiene rubber latex, and the solvent is deionized water.

[0015] Preferably, the battery has a 14C continuous discharge capacity retention rate of ≥95%, an 8C cycle capacity decay of ≤20% after 800 cycles, a 10C cycle capacity decay of ≤20% after 500 cycles, can work effectively in an environment of -40℃ to 60℃, and passes the 150% SOC overcharge test without thermal runaway.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention discloses a high-rate cylindrical all-tab lithium-ion battery and its preparation method, which uses a positive electrode (single crystal and polycrystalline mixed) material: the single crystal small particle material has a large specific surface area, and the adsorption and desorption of lithium ions on its surface are easier. After doping with both, the diffusion channels of lithium ions inside the electrode material are optimized, thereby enhancing cycle stability.

[0017] Smaller particles can fill the gaps between larger particles, allowing for more thorough contact between the active material and the electrolyte. This reduces side reactions during the initial charge and discharge cycle, enabling more active lithium to participate in subsequent electrochemical reactions, thereby increasing the battery's actual usable capacity.

[0018] Doping with both large and small particles can alter the thermal conductivity of cathode materials. The presence of small particles increases the heat conduction path and contact area, which is beneficial for heat dissipation. This high-nickel material provides high capacity and ion diffusion channels. The doping with both large and small particles creates a "buffer zone" at the two-phase interface, which can alleviate volume expansion, reduce local current density, and improve thermal stability.

[0019] The material system adopts mesophase graphite + third-generation silicon-carbon Si@C + single-walled carbon nanotubes (SWCNT): third-generation silane silicon-carbon can reduce the negative electrode expansion rate, which can be controlled within 15% (traditional silicon-carbon reaches 25%, and graphite is about 10%); mesophase carbon microspheres (MCMB) have a nematic ordered carbon layer stacking structure, and their high specific surface area can reduce the diffusion path length and barrier of lithium, and have advantages such as good lithium-ion diffusion, conductivity and mechanical stability.

[0020] The all-tab structure and multi-point pulse welding of the current collector plate significantly shorten the electronic transmission channel, while the multi-point welding structure of the current collector plate increases the contact area and greatly reduces the internal resistance.

[0021] Using swelling tape in cycle testing can improve electrode damage and cell deformation caused by expansion, thereby enhancing cycle performance. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the flattening of the all-polar ear in this invention.

[0024] Figure 2 This is a schematic diagram of the welding of the positive and negative collector disks of the present invention.

[0025] Figure 3 This is a discharge rate data diagram of an embodiment of the present invention.

[0026] Figure 4 This is a comparative diagram of the results of high-rate charge-discharge cycle tests in the embodiments of the present invention.

[0027] Figure 5 This is a comparative diagram of the results of different high-rate charge-discharge cycle tests in the embodiments of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0030] like Figures 1-2 As shown, a high-rate cylindrical full-tab lithium-ion battery includes a positive electrode, a negative electrode, a separator, an electrolyte, a current collector, and a termination tape. The positive electrode uses a high-nickel ternary material with a bimodal particle size distribution and a carbon nanotube-conductive carbon black composite conductive system. The negative electrode uses a mesophase carbon microsphere and a third-generation silane-modified silicon-carbon composite system, with added single-walled carbon nanotubes. The electrolyte is a high-temperature resistant electrolyte containing multiple additives. The current collector and the tabs are laser pulse welded, and the termination tape is a PVDF-based swelling tape.

[0031] The cathode uses a high-nickel ternary material (LiNi) with a bimodal particle size distribution. 0.9 Co 0.05 Mn 0.05 O2 is a mixture of 3μm fine particles and 10μm coarse particles in an optimized ratio, combined with a carbon nanotube (CNT)-conductive carbon black (SP) composite conductive system. The high-nickel ternary material accounts for 95.2% by weight, carbon nanotubes are added at 0.6-1.2wt%, conductive carbon black (SP) at 2.2-2.8wt%, polyvinylidene fluoride (PVDF) is used as a binder (1.2wt%), and 0.3% lithium carbonate is added to suppress interfacial side reactions. The positive electrode slurry is dissolved and dispersed in methylpyrrolidone (NMP), then uniformly coated onto aluminum foil, leaving a 5.5mm empty foil area at the edge of the electrode. After drying and compaction, the coating surface density is controlled at 255-265 g / m². 2 The compacted density is 3.45-3.6 g / cm³. 3 .

[0032] The negative electrode employs a composite system of "mesophase carbon microspheres (MCMB) + third-generation silane-modified silicon-carbon (Si@C) + single-walled carbon nanotubes (SWCNTs)". MCMB and Si@C are compounded at a mass ratio of 9:1 (MCMB has a D50 of 10-14 μm, and Si@C has a particle size of 2-5 μm), with 0.4 wt% of SWCNTs added. The total active material content of the negative electrode is 95.6%, with sodium carboxymethyl cellulose (CMC) as a thickener (1.2 wt%), carbon black as a conductive agent (1.5 wt%), and styrene-butadiene rubber latex (SBR) as a binder (1.6 wt%). After dispersion and stirring with deionized water, a negative electrode slurry is prepared, coated onto copper foil with a 3 mm blank foil area reserved, and dried and compacted to a coating surface density of 9-12 g / m². 2 .

[0033] The electrolyte uses 1 mol / L LiPF6 as the main lithium salt, and the solvent is a mixture of ethylene carbonate (EC), dimethyl carbonate (DMC), and ethyl methyl carbonate (EMC) in a ratio of 2:1:7. 10 wt% fluoroethylene carbonate (FEC), 0.6 wt% ethylene sulfate (DTD), 0.2 wt% 1,3-propanesulfonate lactone (PS), 4 wt% lithium difluorosulfonylimide (LiFSI), and PST and other multi-component additives are added to form a high-temperature resistant and film-forming stable composite electrolyte system.

[0034] The following detailed explanation uses the cylindrical lithium-ion battery model 21700-4000mAh as an example.

[0035] When using cathode materials (a mixture of single-crystal and polycrystalline materials), the single-crystal small particles (3μm) have a large specific surface area (2.8 times higher than a single 10μm particle), more lithium-ion adsorption / desorption active sites, and a short diffusion path (only 1 / 3 that of large particles); the large particles (10μm) provide stable structural support. After doping, the two form a "gradient diffusion channel," which increases the lithium-ion diffusion coefficient from 1.2 × 10⁻⁶ for single-particle materials. -10 cm 2 / s increased to 3.5×10 -10 cm 2 / s, significantly improving rate performance; small particles fill the gaps between large particles, optimizing electrode porosity from 35% to 42% for single-particle sizes, increasing the contact area between active material and electrolyte by 30%, resulting in more uniform SEI film formation during the first charge-discharge process, reducing side reaction current from 0.8mA / g to 0.3mA / g, improving active lithium utilization by 8%, and increasing actual battery capacity from 392mAh to 400mAh (21700 model). The "two-phase interface buffer" formed by large and small particles can absorb the volume expansion of high-nickel materials during cycling (from 8% to 4.2%), reducing local current density (from 120mA / cm). 2 Reduced to 85 mA / cm 2 Small particles increase the heat conduction path, increasing the electrode thermal conductivity from 0.8 W / (m·K) to 1.3 W / (m·K). At 80°C and 14C discharge, the highest battery temperature is reduced from 92°C to 79.3°C, avoiding material phase change and thermal runaway.

[0036] When the anode uses a mesophase graphite + third-generation silicon-carbon (Si@C) + single-walled carbon nanotube (SWCNT) material system, the third-generation silane-modified silicon-carbon, through core-shell structure design (a 5-10 nm carbon layer coating the silicon core surface) and silane coupling agent modification, forms stable Si-C chemical bonds, reducing the volume expansion rate from 25% of second-generation silicon-carbon to 12%. The nematic ordered carbon layer stacking structure of MCMB has excellent mechanical stability, which can further buffer expansion stress, keeping the overall expansion rate of the composite anode below 15%. The high specific surface area (≤2.5 nm) of mesophase graphite... 2 ( / g) Shortening the lithium diffusion path, the diffusion coefficient reaches 2.1×10 -11 cm 2 / s, which is 1.8 times that of ordinary graphite; SWCNT has an aspect ratio (≥1000) and high conductivity (resistivity ≤1×10 4 A continuous conductive network (Ω·cm) is constructed, increasing the electron conductivity of the negative electrode from 10 S / cm to 80 S / cm, significantly reducing polarization loss. The carbon coating layer of third-generation silicon-carbon works synergistically with electrolyte additives (FEC, DTD) to form a dense and stable SEI film (thickness reduced from 80 nm to 45 nm), inhibiting electrolyte decomposition and silicon particle pulverization, and extending cycle life.

[0037] Employing an all-tab structure and multi-point pulse welding of the current collector, the electron transmission path is shortened: Traditional monopole / bipole structures require an electron transmission distance of 50-80mm, while the all-tab structure, through continuous tab design at the electrode edges, reduces this distance to 5-10mm, decreasing the transmission path length by over 80%. Contact resistance is also reduced: the multi-point pulse welding of the current collector and tabs (one welding point every 10mm) increases the contact area from 0.5cm² in traditional single-point welding. 2 Increased to 3.2cm 2 The contact resistance decreased from 8mΩ to 2mΩ, and the overall internal resistance of the battery decreased from 65mΩ to 38mΩ. Current distribution was made more uniform: the all-tab structure ensured that the current was evenly distributed across the electrode surface, avoiding hot spots caused by localized current concentrations. The maximum temperature difference on the electrode surface during 10C discharge decreased from 15℃ to 5℃, improving cycle stability and safety.

[0038] The tape uses PVDF-based swelling termination tape. PVDF-based tape undergoes crystallinity changes and molecular chain relaxation at high temperature (180℃), with a volume expansion rate of ≥150%. This can accurately compensate for the volume expansion during the positive and negative electrode cycling process (total expansion is about 5%-8%), avoiding core loosening and electrode displacement. At the same time, the strong polarity of PVDF can form hydrogen bonds with the electrolyte, improving the adhesion strength between the tape and the electrode (from 0.3N / cm to 0.8N / cm), preventing electrode edge peeling and short circuit risks.

[0039] The following are the experimental verification processes for the examples and comparative examples: Example: Preparation of 21700-4000mAh cylindrical lithium-ion batteries Cathode: High-nickel ternary material (3μm fine particles: 10μm coarse particles = 3:7) 95.2wt%, CNT 0.5wt%, SP 2.8wt%, PVDF 1.2wt%, lithium carbonate 0.3wt%; coating surface density 260g / m² 2 Compacted density 3.5 g / cm³ 3 ; Anode: MCMB 91.6wt%, third-generation silicon-carbon 4wt%, SWCNT 0.1wt%, CMC 1.2wt%, carbon black 1.5wt%, SBR 1.6wt%; coating surface density 10g / m² 2 ; Electrolyte: LiPF6 1mol / L, EC / EMC / DMC = 2:1:7, FEC 10wt%, DTD 0.6wt%, PS 0.2wt%, LiFSI 4wt%; Other: Ceramic-coated PE release film, PVDF swelling tape (50μm), laser pulse welding (welding points ≥20).

[0040] Comparative Example: The only difference from the Example is that the positive electrode uses a single-particle-size (8μm) NCM811 material, the negative electrode uses MCMB+ second-generation silicon carbide (without SWCNT), and the termination tape is ordinary PET tape. Other materials, parameters and processes are the same.

[0041] The performance test results of the examples and comparative examples are compared in the table below: Experimental verification, as shown in the table above, reveals that Example 14 achieved a 103% capacity retention rate at 80°C during 14C discharge, while the comparative example using a single-particle-size 811 cathode only achieved 82%. After 700 cycles, the cathode structure of Example 1 remained intact with no significant pulverization, while the cathode of the comparative example showed severe cracks and active material shedding. After 500 cycles, the anode expansion rate of Example 1 was 13.21%-14.71%, while that of the comparative example (second-generation silicon-carbon) was 21.32%-23.42%. Example 14 achieved a capacity retention rate of >65% after 600 cycles at 10C, while the capacity retention rate of the comparative example dropped to 55% after 400 cycles. The highest discharge rate of Example 1 reached 20C, while that of the comparative example was only 15C. After 500 cycles at 10C discharge, the internal resistance increase of Example 1 was 18%, while that of the comparative example was 42%. After 800 cycles, the cell deformation rate of the example was only 2.1%, while that of the comparative example (ordinary PET tape) was 8.3%. No short-circuit failures were observed in the example, while 30% of the samples in the comparative example showed micro-short circuits caused by electrode edge peeling. See the attached table for test results. Figures 3-5 .

[0042] For the comparison of negative electrode cyclic expansion test (the negative electrode process thickness is 111μm, and the thickness is tested after disassembly after 500 cycles: 10 points from left to right in the middle part of the electrode sheet), the expansion is controlled within 15%.

[0043] Example data: Comparative data: The safety performance test results are as follows; As one possible implementation method: A method for preparing a high-rate cylindrical all-tab lithium-ion battery includes the following steps: S1: Positive Electrode Preparation: A positive electrode slurry is prepared by mixing high-nickel ternary materials, carbon nanotubes, conductive carbon black, binder, and additives with a solvent. This slurry is then coated onto aluminum foil, dried, and compacted, leaving a tab area. The high-nickel positive electrode active material has a weight content (relative to powder weight) of 95.2%; polyvinylidene fluoride (PVDF) is used as a binder with a weight content of 1.2%; and carbon black (SP) is used as a conductive agent with a weight content of 2.8%. A small amount of lithium carbonate (0.3%) is added. The above materials are thoroughly mixed, and then methylpyrrolidone (NMP) is added and stirred thoroughly. Finally, 0.5% carbon nanotube (CNT) conductive paste is added to prepare the positive electrode slurry. The positive electrode slurry is uniformly coated onto the positive current collector aluminum foil, leaving a 5.5mm empty foil area at the edge of the electrode. After drying and compaction, the positive electrode is obtained. S2: Negative Electrode Preparation: A negative electrode slurry is prepared by mixing mesophase carbon microspheres, third-generation silane-modified silicon carbon, single-walled carbon nanotubes, thickener, conductive agent, binder, and solvent. This slurry is coated onto copper foil, dried, and compacted, leaving a tab area. Mesophase graphite (MCMB) with a particle size D50 ≤ 14µm and a specific surface area ≤ 2.5m² / g, with 4% third-generation silane silicon carbon (Si@C) added, serves as the negative electrode active material, with a total weight content of 95.6%. Sodium carboxymethyl cellulose (CMC) is used as the thickener, with a weight content of 1.2%. Carbon black is used as the conductive agent, with a weight content of 1.5%. After uniform mixing of the above materials, deionized water is added and continuously stirred until fully mixed. Single-walled carbon nanotubes (SWCNT, 0.1%) are then added and stirred until uniform. Finally, styrene-butadiene rubber latex (SBR, weight content 1.6%) is added and stirred until uniform to prepare the negative electrode slurry. The negative electrode slurry is evenly coated on the copper foil of the negative electrode current collector, leaving a 3mm empty foil area at the edge of the electrode sheet. After drying and compaction, the negative electrode sheet is obtained.

[0044] S3: Preparation of the separator membrane: Ceramic-coated separator membrane with polyethylene microporous membrane as base membrane.

[0045] S4: Electrolyte Preparation: Dissolve the lithium salt in a mixed solvent, add multi-component additives, and stir until homogeneous. Use lithium hexafluorophosphate as the lithium salt and a mixture of ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) as the solvent, with a ratio of EC / EMC / DMC = 2:1:7. After dissolving the lithium hexafluorophosphate in the mixed solvent (concentration of 1 mol / L), add 10 wt% of electrolyte additives fluoroethylene carbonate (FEC), 0.6 wt% ethylene sulfate (DTD), 0.2 wt% 1,3-propanesulfonate lactone (PS), and 4 wt% lithium salt lithium difluorosulfonylimide (LiFSI) to obtain an electrolyte with high-temperature resistance and film-forming stability.

[0046] S5: Core preparation: The positive electrode sheet, separator, and negative electrode sheet are wound to form a core. The tabs are flattened. The current collector and the tabs are welded to each other by laser pulse multi-point welding. The core is fixed with PVDF-based swelling tape. S6: Battery Assembly: The core is loaded into a cylindrical steel shell, and then subjected to grooving, cap welding, baking, electrolyte injection, encapsulation, formation, and capacity testing to obtain the finished battery.

[0047] The adhesive in step S1 is polyvinylidene fluoride, and the solvent is methylpyrrolidone; the thickener in step S2 is sodium carboxymethyl cellulose, the adhesive is styrene-butadiene rubber latex, and the solvent is deionized water.

[0048] The battery retains ≥95% capacity during 14C continuous discharge, with ≤20% capacity decay after 800 cycles at 8C and ≤20% capacity decay after 500 cycles at 10C. It can operate effectively in environments ranging from -40℃ to 60℃ and has passed the 150% SOC overcharge test without thermal runaway.

[0049] Other technical solutions not described in detail in this invention are all existing technologies in the field and will not be elaborated here.

[0050] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can be modified and varied in various ways. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-rate cylindrical all-tab lithium-ion battery, characterized in that, The device includes a positive electrode, a negative electrode, a separator, an electrolyte, a current collector, and a termination tape. The positive electrode is a high-nickel ternary material with a bimodal particle size distribution and a carbon nanotube-conductive carbon black composite conductive system. The negative electrode is a mesophase carbon microsphere and a third-generation silane-modified silicon-carbon composite system with added single-walled carbon nanotubes. The electrolyte is a high-temperature resistant electrolyte containing multiple additives. The current collector and the tabs are laser pulse welded, and the termination tape is a PVDF-based swelling tape.

2. A high-rate cylindrical all-tab lithium-ion battery according to claim 1, characterized in that, The high-nickel ternary material is LiNi. x Co ᵧ Mn 1-x-y O2; where 0.8≤x≤0.95, 0.02≤y≤0.08, is a mixture of fine particles with a diameter of 2-4μm and coarse particles with a diameter of 8-12μm.

3. A high-rate cylindrical all-tab lithium-ion battery according to claim 1 or 2, characterized in that, The positive electrode contains 0.4-1.5 wt% carbon nanotubes, 2.0-3.0 wt% conductive carbon black, and has a coating surface density of 250-270 g / m². 2 The compacted density is 3.4-3.7 g / cm³. 3 .

4. A high-rate cylindrical all-tab lithium-ion battery according to claim 1, characterized in that, The mass ratio of the mesophase carbon microspheres to the third-generation silane-modified silicon carbon is 8.5-9.5:1, the amount of single-walled carbon nanotubes added is 0.3-0.5 wt%, and the anode coating surface density is 8-13 g / m². 2 .

5. A high-rate cylindrical all-tab lithium-ion battery according to claim 1, characterized in that, The electrolyte uses LiPF6 as the main lithium salt with a concentration of 0.8-1.2 mol / L, and the solvent is a mixture of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate, with a mixing ratio of 1-3:0.5-1.5:6-8. The additives include at least three of the following: fluoroethylene carbonate, ethylene sulfate, 1,3-propanesulfonate lactone, and lithium difluorosulfonylimide.

6. A high-rate cylindrical all-tab lithium-ion battery according to claim 5, characterized in that, The amount of fluoroethylene carbonate added is 8-12 wt%, the amount of ethylene sulfate added is 0.4-0.8 wt%, and the amount of lithium difluorosulfonyl imide added is 3-5 wt%.

7. A high-rate cylindrical all-tab lithium-ion battery according to claim 1, characterized in that, The current collector includes a negative electrode copper-nickel composite current collector with a thickness of 0.15-0.25 mm, and a positive electrode aluminum current collector with a thickness of 0.25-0.35 mm; the termination tape has an initial thickness of 45-55 μm and expands to 120-140 μm at 180°C.

8. A method for preparing a high-rate cylindrical full-tab lithium-ion battery, used to prepare a lithium-ion battery as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Positive electrode preparation: High-nickel ternary material, carbon nanotubes, conductive carbon black, binder and additives are mixed with solvent to form a positive electrode slurry, which is then coated on aluminum foil, dried and compacted, leaving a tab area. S2: Negative electrode preparation: Mesophase carbon microspheres, third-generation silane-modified silicon carbon, single-walled carbon nanotubes, thickener, conductive agent, binder and solvent are mixed to form a negative electrode slurry, which is then coated on copper foil, dried and compacted, leaving a tab area. S3: Preparation of the separator membrane: Ceramic-coated separator membrane with polyethylene microporous membrane as base membrane; S4: Electrolyte preparation: Dissolve lithium salt in a mixed solvent, add multi-component additives, and stir until homogeneous; S5: Core preparation: The positive electrode sheet, separator, and negative electrode sheet are wound to form a core. The tabs are flattened. The current collector and the tabs are welded to each other by laser pulse multi-point welding. The core is fixed with PVDF-based swelling tape. S6: Battery Assembly: The core is loaded into a cylindrical steel shell, and then subjected to grooving, cap welding, baking, electrolyte injection, encapsulation, formation, and capacity testing to obtain the finished battery.

9. A method for preparing a high-rate cylindrical all-tab lithium-ion battery according to claim 1, characterized in that, The adhesive in step S1 is polyvinylidene fluoride, and the solvent is methylpyrrolidone; the thickener in step S2 is sodium carboxymethyl cellulose, the adhesive is styrene-butadiene rubber latex, and the solvent is deionized water.

10. The high-rate cylindrical all-tab lithium-ion battery according to any one of claims 1-7, characterized in that, The battery retains ≥95% capacity during 14C continuous discharge, with ≤20% capacity decay after 800 cycles at 8C and ≤20% capacity decay after 500 cycles at 10C. It can operate effectively in environments ranging from -40℃ to 60℃ and has passed the 150% SOC overcharge test without thermal runaway.

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