CN109786854B - A kind of fast charging lithium ion battery and preparation method thereof - Google Patents

Abstract

The invention discloses a quick-charging lithium ion battery and a preparation method thereof. The quick-charging lithium ion battery is prepared by the following preparation method: 1) respectively preparing positive/negative conductive materials; 2) preparing conductive slurry; 3) mixing the conductive slurry with a conductive material, and coating the mixture on a base material to obtain a positive/negative plate; reserving a blank at the edge of the coating of the pole piece; 4) cutting a reserved blank of the pole piece to form an electrode connecting sheet; 5) coiling the square battery cell, and leading out an electrode connecting sheet; 6) welding the connecting sheet with the metal composite sheet; 7) cutting the connecting sheet; 8) bending and molding the connecting sheet; 9) the exposed connecting sheet is protected by rubberizing; 10) performing top side edge sealing on the semi-finished product of the battery cell; 11) and baking the battery cell, injecting electrolyte, and grading to obtain the quick-charging lithium ion battery. The invention discloses a lithium ion battery capable of being charged at an ultra-fast speed, which can shorten the charging time to be within 15 minutes, and can be charged in 6 minutes to reach more than 90% of the total electric quantity of the battery.

Description

A kind of fast charging lithium ion battery and preparation method thereof

technical field

The invention relates to a lithium ion battery, in particular to a fast charge lithium ion battery and a preparation method thereof.

Background technique

A lithium-ion battery is a secondary battery that mainly relies on the movement of lithium ions between the positive and negative electrodes to work. During the charging and discharging process, Li ⁺ intercalates and deintercalates back and forth between the two electrodes: during charging, Li+ is deintercalated from the positive electrode, intercalated into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; during discharge, the opposite is true.

The advantage of traditional lithium-ion batteries is high energy density, but in order to improve the cruising range, when the battery capacity of the electrical appliance is relatively high, it will face the problem of long charging time. Charging is an important step for battery reuse. The charging process of lithium-ion batteries is divided into two stages: constant current fast charging stage and constant voltage current decreasing stage. In the constant current fast charging stage, the battery voltage gradually increases to the standard voltage of the battery, and then switches to the constant voltage stage under the control chip, the voltage does not increase to ensure that it will not be overcharged, and the current gradually decreases as the battery power increases. to the set value, and finally complete the charging.

Generally speaking, the charging time of current high-capacity lithium-ion batteries is 2 to 5 hours, or even higher, and the user experience is less favorable. Therefore, how to prepare a lithium-ion battery that can achieve fast charging has become a hot issue for industry workers.

SUMMARY OF THE INVENTION

In order to overcome the problems existing in the prior art, the purpose of the present invention is to provide a fast-charging lithium-ion battery and a preparation method thereof.

The technical scheme adopted by the present invention is:

A preparation method of a fast-charging lithium-ion battery, comprising the following steps:

1) carbon coating treatment is performed on the positive electrode active material and the negative electrode active material, respectively, to obtain a positive electrode conductive material and a negative electrode conductive material;

2) mixing graphene, superconducting carbon black, carbon nanotubes, dispersant and solvent to obtain conductive slurry;

3) mixing the conductive slurry with the positive electrode conductive material, and the obtained positive electrode coating is coated on the positive electrode substrate to obtain a positive electrode sheet; the conductive slurry is mixed with the negative electrode conductive material, and the obtained negative electrode coating is coated on the negative electrode substrate to obtain a negative electrode sheet; the coating edges of the positive sheet and the negative sheet are left blank respectively;

4) Cut the reserved blanks of the positive electrode sheet and the negative electrode sheet respectively to form the electrode connecting sheet;

5) Roll the cut positive electrode sheet, negative electrode sheet and separator into a square cell, and the electrode connecting sheets are respectively drawn out in a stacked manner perpendicular to the length of the electrode;

6) Weld the connecting piece drawn from the positive electrode and the negative electrode to the metal composite piece with sealant;

7) Cut the excess connecting piece after welding;

8) Bend the connecting piece in a direction perpendicular to the cross section of the cell;

9) Protect the exposed connecting piece of the cell with glue to obtain the semi-finished product of the cell;

10) Seal the top side of the semi-finished battery cell, and reserve the liquid injection side;

11) Bake the edge-sealed battery cells, then inject electrolyte, and divide the capacity to obtain a fast-charging lithium-ion battery.

Preferably, in step 1) of the preparation method of the fast-charging lithium ion battery, the carbon coating treatment method is specifically: soaking the positive electrode active material or the negative electrode active material in the dispersion liquid of the carbon material respectively, and coating by mixing and dipping. treatment to obtain a positive electrode or a negative electrode composite electrode material coated on the surface, and then spray drying and granulation to obtain a positive electrode or a negative electrode conductive material.

Preferably, in step 1) of the preparation method of the fast-charging lithium ion battery, the mass ratio of the active material (positive electrode or negative electrode) to the carbon material used for carbon coating is 1:(0.05-0.3).

Preferably, in step 1) of the preparation method of the fast-charging lithium-ion battery, the positive active material is lithium cobalt oxide (LCO), lithium manganate (LMO), lithium iron phosphate (LFP), nickel cobalt lithium manganate (NCM) ) at least one of them.

Preferably, in step 1) of the preparation method of the fast-charging lithium ion battery, the negative electrode active material is at least one of amphiphilic carbon material (ACM) and mesocarbon microspheres (MCMB); further preferably, the negative electrode The active material is mesocarbon microspheres.

Preferably, in step 1) of the preparation method of the fast-charging lithium ion battery, the mass concentration of the carbon material in the dispersion liquid is 1% to 10%.

Preferably, in step 1) of the preparation method of the fast-charging lithium ion battery, the carbon material is at least one of carbon nanotubes, carbon fibers, carbon balls, and soft carbon.

Preferably, in step 1) of the preparation method of the fast-charging lithium ion battery, the dispersion liquid of the carbon material may be an alcohol solution, a ketone solution or an amide solution of the carbon material.

Preferably, in step 2) of the preparation method of the fast-charging lithium ion battery, the mass ratio of graphene, superconducting carbon black, carbon nanotubes, dispersant and solvent is (0.5-1): (0.5-2): (0.5 to 1): (0.5 to 1): 100.

Preferably, in step 2) of the preparation method of the fast-charging lithium ion battery, the dispersant is at least one of polyvinylpyrrolidone, polyethylene glycol, polyacrylic acid, and polyacrylate.

Preferably, in step 2) of the preparation method of the fast-charging lithium ion battery, the solvent is N-methylpyrrolidone (NMP), propylene carbonate (PC), ethylene carbonate (EC), dimethyl carbonate (DMC) , at least one of diethyl carbonate (DEC) and ethyl methyl carbonate (EMC).

Preferably, in step 3) of the preparation method of the fast-charging lithium ion battery, the amount of the conductive slurry used accounts for 3% to 20% of the total mass of the positive electrode conductive material or the negative electrode conductive material, respectively.

Preferably, in step 3) of the preparation method of the fast-charging lithium ion battery, after pre-coating a conductive layer on the positive electrode substrate or the negative electrode substrate, the positive electrode coating or the negative electrode coating is applied; the thickness of the conductive layer is 0.5 μm ~3 μm, and the conductive layer is a composite composed of at least two of graphene, superconducting carbon black, carbon nanotubes, Ketjen black, carbon fiber, and carbon microspheres.

Preferably, in step 3) of the preparation method of the fast-charging lithium ion battery, the thickness of the positive electrode substrate is 10 μm˜30 μm, and the material of the positive electrode substrate is preferably aluminum.

Preferably, in step 3) of the preparation method of the fast-charging lithium ion battery, the thickness of the negative electrode substrate is 5 μm˜20 μm, and the material of the negative electrode substrate is preferably copper.

Preferably, in step 3) of the preparation method of the fast-charging lithium ion battery, the coating thickness of the positive electrode sheet or the negative electrode sheet is respectively 70 μm～150 μm, and the reserved length of the coating edge is 10 mm～30 mm blank.

Preferably, in step 4) of the preparation method of the fast-charging lithium ion battery, the length of the electrode connecting sheet is 10 mm˜15 mm.

Preferably, in step 5) of the preparation method of the fast-charging lithium ion battery, the separator is a polyethylene separator with a porosity of 45% to 65% and an air permeability of ≤200s.

Preferably, in step 6) of the preparation method of the fast-charging lithium ion battery, the metal composite sheet with sealant is a copper-aluminum composite sheet with polyacrylate sealant.

Preferably, in step 11) of the preparation method of the fast-charging lithium ion battery, the baking temperature is 70°C to 100°C.

Preferably, in step 11) of the preparation method of the fast-charging lithium ion battery, the injection amount of the electrolyte is 4g/Ah～6g/Ah; the electrolyte is a conventional electrolyte, such as lithium hexafluorophosphate electrolyte.

A fast-charging lithium-ion battery is prepared by the above-mentioned preparation method.

The beneficial effects of the present invention are:

The invention discloses an ultra-fast rechargeable lithium ion battery, which can shorten the charging time within 15 minutes, and can charge more than 90% of the total battery power in 6 minutes.

Compared with the prior art, the present invention has the following advantages:

1. The positive electrode material used is pre-coated and doped with carbon nano-particles to form an excellent conductive layer on the surface of the particles; 2. The negative electrode material used is pre-coated with soft carbon to form an excellent conductive layer on the surface of the particles; 3. The conductive agent used is graphite Alkene, superconducting carbon black and CNT are combined in a certain proportion and added to the electrode sheet. Before use, it needs to be mixed with a specific dispersant and solvent to disperse; 4. The separator used is a special separator with a porosity of 45% to 65%. %, the air permeability is less than or equal to 200s; 5. The structure of the battery cell: the tab is a full tab structure, which is composed of the white edge of the electrode sheet; than ≥90% of the total charge capacity.

Description of drawings

Fig. 1 is the schematic diagram of forming electric core;

Fig. 2 is a schematic diagram of the preparation steps for welding the connecting sheet and the copper-aluminum composite sheet;

Fig. 3 is a schematic diagram of the preparation steps of the cutting of the connecting piece;

Figure 4 is a schematic diagram of the preparation steps of the bending and forming of the connecting piece;

Figure 5 is a schematic diagram of the preparation steps for the protection of exposed metal sheet stickers;

Fig. 6 is the charging voltage-time-temperature curve diagram of the battery of Example 1 at 50A/9C;

7 is a graph of the charging capacity-voltage curve of the battery of Example 1 at 50A/9C.

Detailed ways

FIG. 1 is a schematic diagram of a formed cell of the fast-charging lithium-ion battery of the present invention. In the electric core of the present invention, the pole lugs are of a full lug structure, and the connecting piece is led out by double-headed lugs.

2 to 5 are schematic diagrams of a certain step of preparing the fast-charging lithium-ion battery of the present invention, wherein FIG. 2 corresponds to step 6) of the above-mentioned preparation method, FIG. 3 corresponds to step 7) of the above-mentioned preparation method, and FIG. 4 corresponds to the step of the above-mentioned preparation method 8), Figure 5 corresponds to step 9) of the above preparation method.

The content of the present invention will be described in further detail below with reference to the accompanying drawings 1 to 5 through specific embodiments. The raw materials/devices used in the examples can be obtained from conventional commercial channels unless otherwise specified.

Example 1

A preparation method of a fast-charging lithium-ion battery, comprising the following steps:

1) Mix the NCM523 positive electrode material and the DMF dispersion liquid containing 5wt% carbon nanotubes evenly, the mass ratio of the NCM523 positive electrode material and the carbon nanotubes is 1:0.1, and the obtained mixture is spray-dried and granulated, and graded to obtain a positive electrode conductive material ; Mix the mesocarbon microspheres with the ethanol dispersion liquid containing 2wt% soft carbon, and the mass ratio of the mesocarbon microspheres to the soft carbon is 1:0.05, and the obtained mixture is spray-dried and granulated, and graded to obtain a negative electrode conductive Material.

2) Mix graphene, superconducting carbon black, carbon nanotubes, polyvinylpyrrolidone and N-methylpyrrolidone solvent in a mass ratio of 0.8:2:1:0.8:100 to obtain a conductive slurry.

3) Mix the conductive slurry and the positive electrode conductive material in a mass ratio of 15:100, and uniformly disperse and mix at a high speed. The obtained positive electrode coating is coated on a 12-20 μm substrate, and dried to obtain a positive electrode sheet. The thickness of the positive electrode coating is 100 μm The main material of the base material used is aluminum foil and a conductive layer with a thickness of 1 to 2 μm is pre-coated on its surface, and the conductive layer is a composite of graphene and carbon nanotubes, and its mass ratio is 1:3; the conductive slurry and the negative electrode are conductive The materials are mixed at a mass ratio of 6:100, and are uniformly dispersed and mixed at a high speed. The obtained negative electrode coating is coated on a 6-10 μm substrate to obtain a negative electrode sheet. The thickness of the negative electrode coating is 85 μm; the main material of the substrate used is copper foil. A conductive layer with a thickness of 1 to 2 μm is pre-coated on its surface. The conductive layer is a composite of superconducting carbon black and carbon nanotubes, and its mass ratio is 1:0.5; length of whitespace.

4) Use a laser to cut the reserved blanks of the positive electrode sheet and the negative electrode sheet respectively to form an electrode connecting sheet with a length of 15 mm.

5) Roll the cut positive electrode sheet, negative electrode sheet and separator into a square cell, and the electrode connecting sheets are respectively drawn out in a laminated manner perpendicular to the length of the electrode; the separator used is a high porosity of 53% and an air permeability of 150s Breathable polyethylene diaphragm.

6) Ultrasonic welding the connecting sheets drawn from the positive electrode and the negative electrode and the copper-aluminum composite sheet with polyacrylate sealant respectively, the preparation steps can be seen in FIG. 2 .

7) Cut the excess connection piece after welding, the preparation step can be seen in Figure 3.

8) Bend and shape the connecting sheet in a direction perpendicular to the cross section of the cell. See Figure 4 for this preparation step.

9) Protect the exposed connecting piece of the cell with glue to obtain the semi-finished product of the cell. This preparation step can be seen in Figure 5; the glue used is a corrosion-resistant polyacrylate glue.

10) Put the semi-finished battery cell into the aluminum-plastic film box for edge sealing on the top side, and reserve a side edge for liquid injection.

11) Bake the edge-sealed cells at a temperature of 80° C., and then inject 5Ah/g electrolyte to divide the capacity to obtain a fast-charging lithium-ion battery.

Example 2

A preparation method of a fast-charging lithium-ion battery, comprising the following steps:

1) uniformly mix the lithium iron phosphate positive electrode material with the ethanol dispersion liquid containing 5wt% carbon nanotubes, the mass ratio of the lithium iron phosphate positive electrode material to the carbon nanotubes is 1:0.12, and the obtained mixture is spray-dried and granulated, and classified, A positive electrode conductive material is obtained; the mesocarbon microspheres are uniformly mixed with an ethanol dispersion containing 3 wt % soft carbon, the mass ratio of the mesocarbon microspheres to the soft carbon is 1:0.15, the obtained mixture is spray-dried and granulated, and classified , to obtain a negative electrode conductive material.

2) Mix graphene, superconducting carbon black, carbon nanotubes, polyvinylpyrrolidone and N-methylpyrrolidone solvent in a mass ratio of 0.8:2:0.8:0.5:100 to obtain a conductive slurry.

3) Mix the conductive slurry and the positive electrode conductive material in a mass ratio of 20:100, and uniformly disperse and mix at a high speed. The obtained positive electrode coating is coated on a 12-20 μm substrate, and dried to obtain a positive electrode sheet. The thickness of the positive electrode coating is 100 μm The main material of the base material used is aluminum foil and a conductive layer with a thickness of 1 to 2 μm is pre-coated on its surface, and the conductive layer is a composite of graphene and carbon nanotubes, and its mass ratio is 1:3; the conductive slurry and the negative electrode are conductive The materials are mixed at a mass ratio of 7:100, and are uniformly dispersed and mixed at a high speed. The obtained negative electrode coating is coated on a 6-10 μm substrate to obtain a negative electrode sheet. The thickness of the negative electrode coating is 85 μm; the main material of the substrate is copper foil. A conductive layer with a thickness of 1-2 μm is pre-coated on its surface. The conductive layer is a composite of superconducting carbon black and carbon nanotubes, and its mass ratio is 1:0.5; length of whitespace.

4) Use a laser to cut the reserved blanks of the positive electrode sheet and the negative electrode sheet respectively to form an electrode connecting sheet with a length of 10 mm.

5) Roll the cut positive electrode sheet, negative electrode sheet and separator into a square cell, and the electrode connecting sheets are respectively drawn out in a laminated manner perpendicular to the length of the electrode; the separator used has a porosity of 55% and a high air permeability of 180s. Breathable polyethylene diaphragm.

6) Ultrasonic welding the connecting sheets drawn from the positive electrode and the negative electrode and the copper-aluminum composite sheet with polyacrylate sealant respectively, the preparation steps can be seen in FIG. 2 .

7) Cut the excess connection piece after welding, the preparation step can be seen in Figure 3.

8) Bend and shape the connecting sheet in a direction perpendicular to the cross section of the cell. See Figure 4 for this preparation step.

9) Protect the exposed connecting piece of the cell with glue to obtain the semi-finished product of the cell. This preparation step can be seen in Figure 5; the glue used is a corrosion-resistant polyacrylate glue.

10) Put the semi-finished battery cell into the aluminum-plastic film box for edge sealing on the top side, and reserve a side edge for liquid injection.

11) Bake the edge-sealed cell at a temperature of 90° C., then inject 5Ah/g electrolyte, and divide the capacity to obtain a fast-charging lithium-ion battery.

Example 3

A preparation method of a fast-charging lithium-ion battery, comprising the following steps:

1) Mix the lithium manganate and lithium cobalt oxide cathode materials with a DMF dispersion containing 5 wt % carbon nanotubes evenly, the mass ratio of lithium manganate cathode material and carbon nanotubes is 1:0.12, and the lithium cobalt oxide cathode material and carbon nanotubes are mixed uniformly. The mass ratio of the nanotubes is 1:0.12, and the obtained mixture is spray-dried and granulated, and graded to obtain a positive electrode conductive material; the mesocarbon microspheres are uniformly mixed with an ethanol dispersion containing 4.5 wt % soft carbon, and the mesocarbon microspheres are mixed uniformly. The mass ratio of the ball to the soft carbon is 1:0.1, and the obtained mixture is spray-dried and granulated, and classified to obtain a negative electrode conductive material.

2) Mix graphene, superconducting carbon black, carbon nanotubes, polyvinylpyrrolidone and N-methylpyrrolidone solvent in a mass ratio of 0.5:1:1:0.5:100 to obtain a conductive slurry.

3) Mix the conductive slurry and the positive electrode conductive material in a mass ratio of 20:100, and uniformly disperse and mix at a high speed. The obtained positive electrode coating is coated on a 12-20 μm substrate, and dried to obtain a positive electrode sheet. The thickness of the positive electrode coating is 110 μm ; The main material of the base material used is aluminum foil and a conductive layer with a thickness of 1 to 2 μm is pre-coated on its surface, and the conductive layer is a composite of graphene and carbon nanotubes, and its mass ratio is 1:3; The conductive slurry and the negative electrode are conductive The materials are mixed at a mass ratio of 7:100, and are uniformly dispersed and mixed at a high speed. The obtained negative electrode coating is coated on a 6-10 μm substrate to obtain a negative electrode sheet. The thickness of the negative electrode coating is 80 μm; the main material of the substrate used is copper foil. A conductive layer with a thickness of 1-2 μm is pre-coated on its surface. The conductive layer is a composite of superconducting carbon black and carbon nanotubes, and its mass ratio is 1:0.5; length of whitespace.

4) Use a laser to cut the reserved blanks of the positive electrode sheet and the negative electrode sheet respectively to form an electrode connecting sheet with a length of 10 mm.

5) Roll the cut positive electrode sheet, negative electrode sheet and separator into a square cell, and the electrode connecting sheets are respectively drawn out in a laminated manner perpendicular to the length of the electrode; the separator used is a high porosity of 55% and an air permeability of 180s Breathable polyethylene diaphragm.

6) Ultrasonic welding the connecting sheets drawn from the positive electrode and the negative electrode and the copper-aluminum composite sheet with polyacrylate sealant respectively, the preparation steps can be seen in FIG. 2 .

7) Cut the excess connection piece after welding, the preparation step can be seen in Figure 3.

8) Bend and shape the connecting sheet in a direction perpendicular to the cross section of the cell. See Figure 4 for this preparation step.

9) Protect the exposed connecting piece of the cell with glue to obtain a semi-finished product of the cell. This preparation step can be seen in Figure 5; the glue used is a corrosion-resistant polyacrylate glue.

10) Put the semi-finished battery cell into the aluminum-plastic film box for edge sealing on the top side, and reserve a side edge for liquid injection.

11) Bake the edge-sealed battery cells at a temperature of 90° C., then inject 5Ah/g electrolyte, and divide the capacity to obtain a fast-charging lithium-ion battery.

The finished cell of the fast-charging lithium-ion battery prepared by the embodiment can be seen in FIG. 1 .

Performance Testing

Battery capacity and internal resistance: Table 1 shows the capacity and internal resistance test results of the batteries prepared in Examples 1 to 3 at room temperature.

Table 1 Battery capacity and internal resistance of Examples 1-3

Sample serial number Example 1 Example 2 Example 3 Capacity (Ah) 5.543 5.542 5.530 Internal resistance (mΩ) 0.82 0.82 0.77

High and low temperature rate discharge test: carry out the high and low temperature rate discharge test of the battery of Example 1, fully charge with 1C current, constant current and constant voltage, and then discharge with different rate currents at different temperatures. The discharge capacity and retention rate are shown in the table. 2.

Table 2 Example 1 battery high and low temperature rate discharge test results

Room temperature charging performance: FIG. 6 is a graph showing the charging voltage-time-temperature curve of the battery of Example 1 at 50A/9C. It can be seen from Figure 6 that the voltage of the battery can be raised to 4.20V in only 5 minutes and 45 seconds under the condition of 50A constant current charging, and the battery surface temperature is lower than 45°C during the whole charging process. FIG. 7 is a graph showing the charging capacity-voltage curve of the battery of Example 1 at 50A/9C. Combining with the charging capacity ratio at 4.20V in Figure 7, it can be known that when the charging voltage reaches 4.20V, the charging ratio of the battery is >90%.

Charging rate at different temperatures: First, the battery of Example 1 was discharged at a current of 1C, and then left at different temperatures for 12 hours, respectively, and then charged with constant current at different rates to test its charging performance. The results are shown in Table 3.

Table 3 Charging performance of the battery of Example 1 at different temperatures

Cycle performance: The batteries of Examples 1, 2 and 3 were subjected to a cyclic charge-discharge test at 1C. After 300 cycles of the cycle test, the cycle retention rates of the batteries of Examples 1, 2 and 3 were 93.6%, 92.7% and 93.1, respectively. %, good cycle performance.

Claims (3)

1. a preparation method of fast charging lithium ion battery, is characterized in that: comprise the following steps: 1) The positive electrode active material and the negative electrode active material are respectively subjected to carbon coating treatment to obtain a positive electrode conductive material and a negative electrode conductive material; 2) Mix graphene, superconducting carbon black, carbon nanotubes, dispersant and solvent to obtain conductive slurry; 3) Mix the conductive slurry with the positive electrode conductive material, and coat the obtained positive electrode coating on the positive electrode substrate to obtain a positive electrode sheet; mix the conductive slurry with the negative electrode conductive material, and coat the obtained negative electrode coating on the negative electrode substrate to obtain a negative electrode sheet; the coating edges of the positive sheet and the negative sheet are left blank respectively; 4) Cut the reserved blanks of the positive electrode sheet and the negative electrode sheet respectively to form the electrode connecting sheet; 5) Roll the cut positive electrode sheet, negative electrode sheet and separator into a square cell, and the electrode connecting sheet is drawn out in a laminated manner perpendicular to the length direction of the positive electrode sheet and the negative electrode sheet respectively; 6) Weld the electrode connecting sheet drawn from the positive electrode and the negative electrode respectively to the metal composite sheet with sealant; 7) Cut the excess electrode connection piece after welding; 8) Bend and shape the electrode connecting sheet in the direction perpendicular to the cross section of the cell; 9) Protect the exposed electrode connection sheet of the cell with glue to obtain the semi-finished product of the cell; 10) Seal the top side of the semi-finished battery cell, and reserve the side for liquid injection; 11) Bake the edge-sealed cells, then inject the electrolyte, and divide the capacity to obtain a fast-charging lithium-ion battery; In the step 1), the method of carbon coating treatment is specifically: immersing the positive electrode active material or the negative electrode active material in the dispersion liquid of the carbon material respectively, and obtaining the surface-coated positive electrode or negative electrode composite by mixing the dipping and coating treatment. The electrode material is then granulated by spray drying to obtain a positive electrode or a negative electrode conductive material; wherein, the positive electrode active material is at least one of lithium cobaltate, lithium manganate, lithium iron phosphate, and lithium nickel cobalt manganate; the negative electrode active material is At least one of amphiphilic carbon materials and mesophase carbon microspheres; the carbon material is at least one of carbon nanotubes, carbon fibers, carbon spheres, and soft carbon; In the step 2), the mass ratio of graphene, superconducting carbon black, carbon nanotubes, dispersant and solvent is (0.5~1):(0.5~2):(0.5~1):(0.5~1) : 100; the dispersant is at least one of polyvinylpyrrolidone, polyethylene glycol, polyacrylic acid, and polyacrylate; In the step 3), the coating thickness of the positive electrode sheet or the negative electrode sheet is respectively 70 μm~150 μm, and the reserved length of the coating edge is 10 mm~30 mm blank; In the step 4), the length of the electrode connecting piece is 10mm~15mm; In the step 5), the diaphragm is a polyethylene diaphragm with a porosity of 45% to 65% and an air permeability of ≤200s; In the step 6), the metal composite sheet with sealant is a copper-aluminum composite sheet with polyacrylate sealant; In the step 11), the baking temperature is 70°C~100°C; the injection amount of the electrolyte is 4g/Ah~6g/Ah; The tabs of the battery core are of a full tab structure, and the electrode connecting pieces are drawn out from the double-ended tabs. 2. The method for preparing a fast-charging lithium-ion battery according to claim 1, wherein in step 3), the amount of the conductive slurry accounts for 3% to 20% of the total mass of the positive electrode conductive material or the negative electrode conductive material, respectively. . 3. A fast-charging lithium-ion battery, characterized in that: it is prepared by the preparation method described in any one of claims 1-2.

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