Soft package lithium slurry battery prepared based on 3D printing technology and preparation method of soft package lithium slurry battery

Abstract

The invention provides a soft package lithium slurry battery prepared based on a 3D printing technology and a preparation method of the soft package lithium slurry battery. The soft package lithium slurry battery comprises a positive electrode current collector, a positive electrode slurry electrode layer, a diaphragm, a negative electrode slurry electrode layer and a negative electrode current collector. And the positive / negative electrode slurry electrode layer is obtained by shearing and mixing materials such as positive and negative electrode active substances, a conductive agent and an additive with an electrolyte at a high speed. Positive and negative electrode slurry electrodes are printed on a current collector through battery 3D printing equipment, and the battery can be directly packaged after a diaphragm is placed between the positive and negative electrode slurry electrodes and the current collector. The lithium slurry battery prepared by the method does not need baking and liquid injection links in the manufacturing process, the battery can be manufactured after slurry homogenization is completed, multi-layer amplification preparation can be realized, uniform distribution and accurate structure control of materials are realized, the capacity and the performance of the battery are improved, meanwhile, the production process is simplified, and material waste is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to a soft-pack lithium slurry battery prepared based on 3D printing technology and a preparation method thereof. Background Art

[0002] The traditional lithium-ion battery manufacturing process usually includes multiple steps such as coating, drying, die-cutting, injection, and packaging, which have many steps and complex production processes. In addition, the energy consumption of the pole piece baking is high during the battery preparation process, and the organic solvent is volatile and there is a risk of environmental pollution.

[0003] All or part of the electrodes of lithium slurry batteries are composed of slurry consisting of active material particles, conductive agents, additive binders and electrolytes. In the preparation process, the expensive preparation steps of traditional lithium-ion battery thin electrodes, such as precision coating and pole piece baking, can be eliminated, simplifying the production process and significantly reducing battery costs. It is conducive to the recycling of scrapped batteries. After low-cost regeneration, the materials can be reused in the manufacture of new batteries, avoiding the high cost and high pollution recycling steps of acid and alkali treatment of scrapped lithium batteries.

[0004] With the continuous development and maturity of 3D printing technology, its application in the field of battery manufacturing has also emerged. 3D battery printing technology can build complex three-dimensional structures by stacking materials layer by layer, thereby realizing the customization of battery shape and size. The use of battery 3D printing technology for lithium slurry battery development can simplify the lithium battery production process, improve material utilization, and make the shape and size of the battery flexibly customized according to actual needs, which has important industrial strategic significance.

[0005] Patent CN 110752354 A discloses a universal 3D printed nano-electrode slurry and its preparation method; the nano-electrode active material, conductive agent, binder, dispersant, the weight ratio of the nano-electrode active material, the conductive agent and the binder is 5-7:2-4:1, and the volume of the dispersant is 2-5mL:1g to the total weight of the nano-electrode active material, the conductive agent and the binder; the above raw materials are made into 3D printed nano-electrode slurry by high-speed grinding and shearing; when applied, the electrode slurry is printed on the carrier by 3D printing, then soaked in deionized water, taken out and freeze-dried to obtain the electrode. In this invention, the solvent or water in the electrode slurry needs to be removed by drying or freeze-drying, and the subsequent preparation of the battery requires injection and other operations, which are cumbersome and energy-intensive. Compared with the traditional method of preparing battery electrodes, the preparation method of this 3D printed electrode does not have much advantage. Summary of the invention

[0006] In view of the technical problems of traditional lithium batteries and the above lithium batteries with complex preparation processes, high energy consumption and high production costs, the present invention proposes a soft-pack lithium slurry battery prepared based on 3D printing technology and a preparation method thereof. The traditional lithium battery production process is optimized, thereby improving the lithium battery production efficiency and reducing production costs and environmental pollution.

[0007] In order to achieve the above object, the technical solution of the present invention is achieved as follows: A method for preparing a soft-pack lithium slurry battery based on 3D printing technology, the steps are as follows: (1) Preparation of electrode slurry: Dry-mix the positive / negative electrode active material and conductive agent at an ambient temperature of 20-30°C and a dew point temperature below -50°C by high-speed stirring, and then wet-mix them with additives and electrolyte by high-speed shearing to form uniform positive / negative electrode slurry; (2) Preparing a slurry electrode positive / negative electrode: The positive / negative electrode slurry of step (1) is printed on the positive / negative current collector by using 3D printing technology to obtain a slurry electrode positive / negative electrode; (3) Assembling batteries: stacking the slurry electrode positive electrode, separator, and slurry electrode negative electrode in order, and vacuum packaging to obtain a soft-pack lithium slurry battery cell.

[0008] Preferably, in step (2), the positive / negative electrode slurry is printed on both sides of the positive / negative current collector respectively using 3D printing technology, and in step (3), the slurry electrode positive electrode, the separator, and the slurry electrode negative electrode are stacked in multiple layers to obtain a soft-pack lithium slurry battery cell.

[0009] Preferably, the rotation speed of the high-speed stirring dry mixing in step (1) is 800-2500 rpm, and the stirring time is 60-120 seconds.

[0010] Preferably, the high-speed shear wet mixing program in step (1) is set to three stages, which are: a rotation speed of 400-1000 rpm and a stirring time of 10-60 s; a rotation speed of 1200-2500 rpm and a stirring time of 20-120 s; a rotation speed of 1000-2000 rpm and a stirring time of 180-600 s; and the viscosity of the electrode slurry is 3000-10000 mPa·S.

[0011] Preferably, in step (1), the mass ratio of the positive / negative electrode active material, the conductive agent and the additive is (30-80): (1-5): (0.1-5); the electrolyte comprises a solvent and a lithium salt; the molar concentration of the lithium salt in the electrolyte is 0.5-3 mol / L; and the mass of the electrolyte accounts for 20%-70% of the mass of the electrode slurry.

[0012] Preferably, in step (1), the solvent is any one or more of ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate and ethylene glycol dimethyl ether; the lithium salt is any one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium bis(oxalate)borate, lithium bis(fluorosulfonyl)imide, lithium difluorooxalatoborate, lithium bis(trifluoromethanesulfonyl)imide and lithium difluorophosphate.

[0013] Preferably, in step (1), the positive electrode active material is any one or more of lithium iron phosphate, lithium manganese phosphate, lithium silicate, lithium iron silicate, doped lithium manganese oxide, lithium cobalt oxide, lithium titanium oxide, lithium vanadium oxide, lithium nickel manganese oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel aluminum oxide, lithium nickel cobalt manganese oxide or lithium iron nickel manganese oxide; the negative electrode active material is any one or more of graphite, silicon carbon, silicon oxygen, lithium titanate, lithium carbonate, carbon nanotubes, nano alloy materials, nano oxides, sulfur-carbon complexes, sulfur, titanium sulfur compounds, molybdenum sulfur compounds, iron sulfur compounds, tin-based compounds, lithium-containing transition metal nitrides, tin-based alloys, silicon-based alloys, germanium-based alloys, aluminum-based alloys, antimony-based alloys and magnesium-based alloys.

[0014] Preferably, in step (1), the conductive agent is one or more of carbon black, Ketjen black, acetylene black, carbon nanotubes, carbon fibers, graphene, graphene oxide and metal conductive particles; the additive is one or more of polyvinyl pyrrolidone, sodium polyacrylate, polyurethane, polyvinyl alcohol, amino acid dispersant, Triton X-100, polyethylene oxide, polyacrylonitrile, polymethyl methacrylate and polyvinylidene fluoride.

[0015] Preferably, in step (2), the positive electrode current collector is any one of aluminum foil and carbon-coated aluminum foil, and the negative electrode current collector is any one of aluminum foil, copper foil, carbon-coated aluminum foil and carbon-coated copper foil; and the separator in step (3) is any one of single-layer PP, single-layer PE, PP ceramic coating, PE ceramic coating, double-layer PP / PE, double-layer PP / PP and triple-layer PP / PE / PP.

[0016] Preferably, the thickness of the positive electrode slurry or negative electrode slurry on the current collector in step (2) is 50-500 μm; the temperature of the vacuum packaging in step (3) is 85-185° C., the vacuum range is 0.1-101.3 KPa, the pressure holding time is 2-10S, and the vacuum sealing time is 1-3S.

[0017] Preferably, the soft-pack lithium slurry battery prepared by the method is manufactured based on 3D printing technology, and the soft-pack lithium slurry battery is printed and stacked in multiple layers in a cycle.

[0018] The present invention has the following beneficial effects: (1) In the present invention, the electrolyte and the electrode active material are subjected to a high-speed stirring process to prepare an electrode slurry. The obtained electrode slurry can be used to print the positive and negative electrode slurry electrodes on the current collector using a battery 3D printing device to obtain a battery electrode. The prepared electrode does not need to be subsequently baked, saving energy. After placing a separator between the positive and negative electrodes of the obtained battery, the battery can be directly packaged and the battery can be manufactured. The battery does not need to be injected with electrolyte to prepare the battery, shortening the lithium battery production process.

[0019] (2) The lithium slurry battery manufacturing process adopted by the present invention replaces the traditional wet coating process in the manufacturing process, and does not require baking and liquid injection steps, thereby simplifying equipment investment, reducing costs, and shortening the battery manufacturing time.

[0020] (3) The battery 3D printing process used in this application can realize multi-layer enlarged preparation, and can also manufacture complex-shaped and customized batteries to meet different application requirements, achieve uniform distribution of materials and precise structural control, improve battery capacity and performance, and reduce material waste.

[0021] (4) The battery 3D printing and battery packaging technology adopted by the present invention can be applied to slurry electrodes with a wide range of solid content and viscosity, and can effectively control the thickness of the slurry electrode in the lithium slurry soft-pack battery, so that the slurry electrode maintains its original state in the lithium slurry battery, is not prone to deformation and casting, and ensures the consistency of the battery.

[0022] (5) The battery 3D printing technology adopted in the present invention can fill the gap of the lack of dedicated equipment for the large-scale preparation of lithium slurry batteries, and can solve the problem of the inability to accurately coat high-solid content and high-viscosity slurry when preparing lithium slurry batteries, thereby realizing the large-scale production of lithium slurry batteries and improving the energy density of lithium slurry batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 It is a schematic diagram of the preparation process of the lithium slurry battery of the present invention.

[0025] Figure 2 is a scanning electron microscope image of the positive / negative electrode slurry, where Figure 2 The left picture is an electron microscope image of the positive lithium iron phosphate slurry electrode. Figure 2 The right picture is an electron microscope image of the negative electrode lithium titanate slurry electrode.

[0026] Figure 3 This is the electrical performance diagram of lithium slurry battery. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1 This embodiment provides a method for preparing a soft-pack lithium slurry battery based on 3D printing technology, and its preparation process diagram is as follows: Figure 1 As shown, the steps are as follows: (1) In an environment with an ambient temperature of 25°C and a dew point temperature below -50°C, 40g of the positive electrode active material lithium iron phosphate and 5g of the conductive agent carbon black are respectively stirred and dry-mixed at high speed until a powder mixture is obtained. The conditions for high-speed stirring and dry-mixing using a vacuum degassing machine are: stirring at a speed of 1000rpm for 100s; (2) In the electrolyte, propylene carbonate is used as a solvent and lithium bis(trifluoromethanesulfonyl)imide is used as a lithium salt to prepare an electrolyte solution with a lithium salt concentration of 0.5M (mol / L); 45g of the powder mixture in the above step (1) and 0.45g of the additive TritonX-100 are mixed with 27.5g of the electrolyte at an ambient temperature of 25°C and a dew point temperature below -50°C for high-speed shear wet mixing. The equipment used is a vacuum degassing mixer. The high-speed shear wet mixing program is set to three stages, which are: stirring at a speed of 800 rpm for 20 seconds; stirring at a speed of 2200 rpm for 50 seconds; stirring at a speed of 1800 rpm for 200 seconds; forming a fluid electrode slurry, and the viscosity of the electrode slurry is 4900 mPa·S; (3) placing the fluid electrode slurry in the above step (2) into the nozzle of the battery 3D printing equipment at an ambient temperature of 25°C and a dew point temperature below -50°C, and extruding it through the nozzle onto the positive electrode current collector carbon-coated aluminum foil in an environment at an ambient temperature of 25°C and a dew point temperature below -50°C to form a positive electrode slurry electrode layer with a thickness of 300 μm, and placing a PP ceramic coated diaphragm on top; (4) The negative electrode active material used in the preparation of the negative electrode slurry is 20g of lithium titanate, and the remaining steps are the same as the preparation process of the positive electrode self-supporting electrode sheet. The negative electrode current collector is carbon-coated aluminum foil; the negative electrode slurry is extruded through a nozzle to form a negative electrode slurry electrode layer with a thickness of 300μm.

[0029] (5) The positive / negative electrode sheets and the diaphragm sheets prepared by the battery 3D printing equipment are stacked to form a single-cell battery with a battery specification size of 75*105cm.

[0030] The battery cells were placed in a thermoplastic film and sealed by vacuum sealing. The temperature of the vacuum sealing was 85°C, the vacuum was 0.5 Kpa, the pressure holding time was 3s, and the vacuum sealing time was 1s. The battery assembly process was completed.

[0031] like Figure 2 The following is a scanning electron microscope image of the positive / negative electrode slurry of the battery. It can be seen that the active material and the conductive agent in the positive and negative electrode material slurry are evenly mixed and are below the micron level, making it easy to prepare the corresponding electrodes by 3D printing. Figure 3 As shown, the initial charge and discharge efficiency of the lithium slurry battery prepared by battery 3D printing technology is 87.75%.

[0032] Example 2 The preparation method of the soft-pack lithium slurry battery based on 3D printing technology in this embodiment comprises the following steps: (1) In an environment with an ambient temperature of 30°C and a dew point temperature below -50°C, 30g of positive electrode active material lithium manganese phosphate and 1g of conductive agent Ketjen black were dry mixed and dry mixed at high speed to obtain a powder mixture. The conditions for high-speed stirring and dry mixing using a vacuum degassing machine are: stirring at a speed of 800 rpm for 120 seconds; (2) The electrolyte solution is prepared with propylene carbonate as solvent and lithium bis(trifluoromethanesulfonyl)imide as lithium salt to form an electrolyte solution with a lithium salt concentration of 2M (mol / L); 31 g of the powder mixture in the above step (1) and 0.1 g of the additive sodium polyacrylate are mixed with 20 g of the electrolyte at an ambient temperature of 25°C and a dew point temperature below -50°C by high-speed shear wet mixing, the equipment used is a vacuum degassing machine, and the high-speed shear wet mixing program is set to three stages, namely: stirring time at 400 rpm for 60 s; stirring time at 2500 rpm for 20 s; stirring time at 2000 rpm for 180 s; forming a fluid electrode slurry, the viscosity of the electrode slurry is 5200 mPa·S; (3) The fluid electrode slurry in the above step (2) is placed in the nozzle of the battery 3D printing equipment at an ambient temperature of 25°C and a dew point temperature below -50°C, and extruded through the nozzle on the positive electrode current collector aluminum foil in an environment with an ambient temperature of 25°C and a dew point temperature below -50°C to form a positive electrode slurry electrode layer with a thickness of 100 μm, and a single-layer PP separator is placed on top; (4) The negative electrode active material used in the preparation of the negative electrode self-supporting electrode sheet is 30g of lithium carbonate, and the remaining steps are the same as the preparation of the positive electrode self-supporting electrode sheet. The negative electrode current collector is aluminum foil; the negative electrode slurry is extruded through a nozzle to form a negative electrode slurry electrode layer with a thickness of 100μm.

[0033] (5) The positive / negative electrode sheets and diaphragm laminates prepared by the battery 3D printing equipment are stacked. The number of laminate layers is 15. They are placed in a thermoplastic film and the battery cells are encapsulated by vacuum sealing. The vacuum sealing temperature is 85°C, the vacuum degree is 0.1 KPa, the pressure holding time is 2 s, and the vacuum sealing time is 1 s. The battery assembly process is completed.

[0034] Example 3 The preparation method of the soft-pack lithium slurry battery based on 3D printing technology in this embodiment comprises the following steps: (1) In an environment with an ambient temperature of 25°C and a dew point temperature below -50°C, 80g of lithium iron phosphate, a positive electrode active material, and 5g of carbon black, a conductive agent, are dry-mixed and mixed evenly until a powder mixture is obtained. The conditions for high-speed stirring and dry mixing using a vacuum degassing machine are: stirring at a speed of 2500rpm for 60s; (2) The electrolyte solution is prepared with propylene carbonate as solvent and lithium bis(trifluoromethanesulfonyl)imide as lithium salt to form an electrolyte solution with a lithium salt concentration of 3M (mol / L); 85g of the powder mixture in the above step (1), 5g of the additive polyvinyl alcohol and 23g of the electrolyte are subjected to high-speed shear wet mixing in a vacuum degassing machine at an ambient temperature of 25°C and a dew point temperature below -50°C. The high-speed shear wet mixing program is set to three stages, namely: stirring at a speed of 1000 rpm for 10s; stirring at a speed of 1200 rpm for 120s; stirring at a speed of 1000 rpm for 600s; to form a fluid electrode slurry, and the viscosity of the electrode slurry is 9000 mPa·S; (3) placing the fluid electrode slurry in the above step (2) into the nozzle of the battery 3D printing equipment at an ambient temperature of 25°C and a dew point temperature below -50°C, and extruding it through the nozzle onto the positive electrode current collector carbon-coated aluminum foil in an environment at an ambient temperature of 25°C and a dew point temperature below -50°C to form a positive electrode slurry electrode layer with a thickness of 300 μm, and placing a double-layer PP / PP separator on top; (4) The negative electrode active material used in the preparation of the negative electrode self-supporting electrode sheet is 20g of lithium titanate, and the remaining steps are the same as the preparation process of the positive electrode self-supporting electrode sheet. The negative electrode current collector is carbon-coated aluminum foil; the negative electrode slurry is extruded through a nozzle to form a negative electrode slurry electrode layer with a thickness of 300μm.

[0035] (5) The stacked positive / negative electrode sheets and diaphragm laminates prepared by the battery 3D printing equipment, with the number of laminate layers being 5, are placed in a thermoplastic film, and the battery cells are encapsulated by vacuum sealing. The vacuum sealing temperature is 185°C, the vacuum degree is 101.3 KPa, the pressure holding time is 1 s, and the vacuum sealing time is 3 s; thus completing the battery assembly process.

[0036] Example 4 The preparation method of the soft-pack lithium slurry battery based on 3D printing technology in this embodiment comprises the following steps: (1) In an environment with an ambient temperature of 25°C and a dew point temperature below -50°C, 20g of positive electrode active material lithium cobalt oxide and 1.5g of conductive agent carbon black are dry mixed and mixed evenly until a powder mixture is obtained. The conditions for high-speed stirring and dry mixing using a vacuum degassing machine are: stirring at a speed of 1500rpm for 100s; (2) The electrolyte solution is prepared with propylene carbonate as solvent and lithium bis(trifluoromethanesulfonyl)imide as lithium salt to form an electrolyte solution with a lithium salt concentration of 0.5M (mol / L); 21.5g of the powder mixture in the above step (1) and 1g of the additive polyvinyl pyrrolidone are mixed with 50g of the electrolyte in a vacuum degassing machine at an ambient temperature of 25°C and a dew point temperature below -50°C, and then subjected to high-speed shear wet mixing. The high-speed shear wet mixing program is set to three stages, namely: stirring time at a speed of 600 rpm for 40 seconds; stirring time at a speed of 1800 rpm for 80 seconds; stirring time at a speed of 1500 rpm for 300 seconds; to form a fluid electrode slurry, and the viscosity of the electrode slurry is 3200 mPa·S; (3) placing the fluid electrode slurry in the above step (2) into the nozzle of the battery 3D printing equipment at an ambient temperature of 25°C and a dew point temperature below -50°C, and extruding it onto the positive electrode current collector aluminum foil through the nozzle at an ambient temperature of 25°C and a dew point temperature below -50°C to form a positive electrode slurry electrode layer with a thickness of 300 μm, and placing three layers of PP / PE / PP separator on top; (4) The negative electrode active material used in the preparation of the negative electrode self-supporting electrode sheet is 20g of lithium titanate, and the remaining steps are the same as the preparation process of the positive electrode self-supporting electrode sheet. The negative electrode current collector is copper foil; the negative electrode slurry is extruded through a nozzle to form a negative electrode slurry electrode layer with a thickness of 300μm.

[0037] (5) The positive / negative electrode sheets and diaphragm stacks prepared by the battery 3D printing equipment, with 10 layers of stacks, are placed in a thermoplastic film, and the battery cells are encapsulated by vacuum sealing. The vacuum sealing temperature is 120°C, the vacuum degree is 50Kpa, the pressure holding time is 5S, and the vacuum sealing time is 23S; the battery assembly process is completed.

[0038] Example 5 The preparation method of the soft-pack lithium slurry battery based on 3D printing technology in this embodiment comprises the following steps: (1) In an environment with an ambient temperature of 25°C and a dew point temperature below -50°C, 20g of lithium iron phosphate, a positive electrode active material, and 2g of carbon black, a conductive agent, are dry-mixed and mixed evenly until a powder mixture is obtained. The conditions for high-speed stirring and dry mixing using a vacuum degassing machine are: stirring at a speed of 1300 rpm for 80 seconds; (2) The electrolyte solution is prepared with propylene carbonate as solvent and lithium bis(trifluoromethanesulfonyl)imide as lithium salt to form an electrolyte solution with a lithium salt concentration of 0.5M (mol / L); 22g of the powder mixture in the above step (1) and 2g of the additive polyurethane are mixed with 30g of the electrolyte in a vacuum degassing machine at an ambient temperature of 25°C and a dew point temperature below -50°C for high-speed shear wet mixing, and the high-speed shear wet mixing program is set to three stages, namely: stirring time at a speed of 600 rpm for 40s; stirring time at a speed of 1500 rpm for 60s; stirring time at a speed of 1200 rpm for 300s; to form a fluid electrode slurry, and the viscosity of the electrode slurry is 3400 mPa·S; (3) The fluid electrode slurry in the above step (2) is placed in the nozzle of the battery 3D printing equipment at an ambient temperature of 25°C and a dew point temperature below -50°C, and extruded through the nozzle on the positive electrode current collector aluminum foil in an environment with an ambient temperature of 25°C and a dew point temperature below -50°C to form a positive electrode slurry electrode layer with a thickness of 100 μm, and a PP ceramic coated separator is placed on top; (4) The negative electrode active material used in the preparation of the negative electrode self-supporting electrode sheet is 20g of lithium titanate, and the remaining steps are the same as the preparation process of the positive electrode self-supporting electrode sheet. The negative electrode current collector is a carbon-coated copper foil; the negative electrode slurry is extruded through a nozzle to form a negative electrode slurry electrode layer with a thickness of 300μm.

[0039] (5) The stacked positive / negative electrode sheets and diaphragm sheets prepared by the battery 3D printing equipment, with 20 layers of stacked sheets, are placed in a thermoplastic film, and the battery cells are encapsulated by vacuum sealing. The vacuum sealing temperature is 100°C, the vacuum degree is 20KPa, the pressure holding time is 5s, and the vacuum sealing time is 3s; the battery assembly process is completed.

[0040] Example 6 The preparation method of the soft-pack lithium slurry battery based on 3D printing technology in this embodiment comprises the following steps: (1) In an environment with an ambient temperature of 25°C and a dew point temperature below -50°C, 50g of positive electrode active material lithium nickel manganese oxide and 3g of conductive agent carbon black are dry mixed and mixed evenly until a powder mixture is obtained. The conditions for high-speed stirring and dry mixing using a vacuum degassing machine are: stirring at a speed of 1500rpm for 100s; (2) The electrolyte solution is prepared with propylene carbonate as solvent and lithium bis(trifluoromethanesulfonyl)imide as lithium salt to form an electrolyte solution with a lithium salt concentration of 0.5M (mol / L); 53g of the powder mixture in the above step (1) and 2g of the additive sodium polyacrylate are mixed with 25g of the electrolyte in a vacuum degassing machine at an ambient temperature of 25°C and a dew point temperature below -50°C, and then subjected to high-speed shear wet mixing. The high-speed shear wet mixing program is set to three stages, namely: stirring at a speed of 600 rpm for 50 seconds; stirring at a speed of 1800 rpm for 80 seconds; and stirring at a speed of 1200 rpm for 300 seconds to form a fluid electrode slurry, and the viscosity of the electrode slurry is 6300 mPa·S; (3) placing the fluid electrode slurry in the above step (2) into the nozzle of the battery 3D printing equipment at an ambient temperature of 25°C and a dew point temperature below -50°C, and extruding it through the nozzle onto the positive electrode current collector carbon-coated aluminum foil in an environment at an ambient temperature of 25°C and a dew point temperature below -50°C to form a positive electrode slurry electrode layer with a thickness of 300 μm, and placing a double-layer PP / PE separator on top; (4) The negative electrode active material used in the preparation of the negative electrode self-supporting electrode sheet is 20g of lithium titanate, and the remaining steps are the same as the preparation process of the positive electrode self-supporting electrode sheet. The negative electrode current collector is a carbon-coated copper foil; the negative electrode slurry is extruded through a nozzle to form a negative electrode slurry electrode layer with a thickness of 400μm.

[0041] (5) The positive / negative electrode sheets and diaphragm laminates prepared by the battery 3D printing equipment are stacked, with 20 layers, placed in a thermoplastic film, and the battery cells are encapsulated by vacuum sealing. The vacuum sealing temperature is 155°C, the vacuum degree is 10KPa, the pressure holding time is 2s, and the vacuum sealing time is 1s; the battery assembly process is completed.

[0042] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a soft-pack lithium slurry battery based on 3D printing technology, characterized in that: The steps include: (1) Preparation of electrode slurry: Dry-mix the positive / negative electrode active material and conductive agent at an ambient temperature of 20-30°C and a dew point temperature below -50°C by high-speed stirring, and then wet-mix them with additives and electrolyte by high-speed shearing to form uniform positive / negative electrode slurry; (2) Preparing a slurry electrode positive / negative electrode: The positive / negative electrode slurry of step (1) is printed on the positive / negative current collector by using 3D printing technology to obtain a slurry electrode positive / negative electrode; (3) Assembling batteries: stacking the slurry electrode positive electrode, separator, and slurry electrode negative electrode in order, and vacuum packaging to obtain a soft-pack lithium slurry battery cell.

2. The method for preparing a soft-pack lithium slurry battery based on 3D printing technology according to claim 1, characterized in that: In the step (1), the rotation speed of the high-speed stirring dry mixing is 800-2500 rpm, and the stirring time is 60-120 seconds.

3. The method for preparing a soft-pack lithium slurry battery based on 3D printing technology according to claim 1, characterized in that: The high-speed shear wet mixing program in step (1) is set to three stages, namely: a rotation speed of 400-1000 rpm and a stirring time of 10-60 s; a rotation speed of 1200-2500 rpm and a stirring time of 20-120 s; a rotation speed of 1000-2000 rpm and a stirring time of 180-600 s; the viscosity of the electrode slurry is 3000-10000 mPa·S.

4. The method for preparing a soft-pack lithium slurry battery based on 3D printing technology according to claim 1, characterized in that: In the step (1), the mass ratio of the positive / negative electrode active material, the conductive agent and the additive is (30-80): (1-5): (0.1-5); the electrolyte comprises a solvent and a lithium salt; the molar concentration of the lithium salt in the electrolyte is 0.5-3 mol / L; and the mass of the electrolyte accounts for 20%-70% of the mass of the electrode slurry.

5. The method for preparing a soft-pack lithium slurry battery based on 3D printing technology according to any one of claims 1 to 4, characterized in that: In the step (1), the solvent is any one or more of ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, propylene carbonate and ethylene glycol dimethyl ether; the lithium salt is any one or more of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium bis(oxalate)borate, lithium bis(fluorosulfonyl)imide, lithium difluorooxalatoborate, lithium bis(trifluoromethanesulfonyl)imide and lithium difluorophosphate.

6. The method for preparing a soft-pack lithium slurry battery based on 3D printing technology according to claim 5, characterized in that: In the step (1), the positive electrode active material is any one or more of lithium iron phosphate, lithium manganese phosphate, lithium silicate, lithium iron silicate, doped lithium manganese oxide, lithium cobalt oxide, lithium titanium oxide, lithium vanadium oxide, lithium nickel manganese oxide, lithium nickel cobalt oxide, lithium nickel cobalt aluminum oxide, lithium nickel aluminum oxide, lithium nickel cobalt manganese oxide or lithium iron nickel manganese oxide; the negative electrode active material is any one or more of graphite, silicon carbon, silicon oxygen, lithium titanate, lithium carbonate, nanocarbon tubes, nanoalloy materials, nanooxides, sulfur-carbon complexes, sulfur, titanium sulfur compounds, molybdenum sulfur compounds, iron sulfur compounds, tin-based compounds, lithium-containing transition metal nitrides, tin-based alloys, silicon-based alloys, germanium-based alloys, aluminum-based alloys, antimony-based alloys and magnesium-based alloys.

7. The method for preparing a soft-pack lithium slurry battery based on 3D printing technology according to claim 5, characterized in that: In step (1), the conductive agent is one or more of carbon black, ketjen black, acetylene black, carbon nanotubes, carbon fibers, graphene, graphene oxide and metal conductive particles; the additive is one or more of polyvinyl pyrrolidone, sodium polyacrylate, polyurethane, polyvinyl alcohol, amino acid dispersant, Triton X-100, polyethylene oxide, polyacrylonitrile, polymethyl methacrylate and polyvinylidene fluoride.

8. The method for preparing a soft-pack lithium slurry battery based on 3D printing technology according to claim 5, characterized in that: In the step (2), the positive electrode current collector is any one of aluminum foil and carbon-coated aluminum foil, and the negative electrode current collector is any one of aluminum foil, copper foil, carbon-coated aluminum foil and carbon-coated copper foil; the thickness of the positive electrode slurry or the negative electrode slurry on the current collector in the step (2) is 50-500 μm.

9. The method for preparing a soft-pack lithium slurry battery based on 3D printing technology according to claim 5, characterized in that: In the step (3), the diaphragm is any one of single-layer PP, single-layer PE, PP ceramic coating, PE ceramic coating, double-layer PP / PE, double-layer PP / PP and triple-layer PP / PE / PP; the vacuum packaging temperature is 85-185°C, the vacuum range is 0.1-101.3Kpa, the pressure holding time is 2-10S, and the vacuum sealing time is 1-3S.

10. A soft-pack lithium slurry battery prepared by the method based on 3D printing technology according to any one of claims 1 to 9.

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