Curved-surface solid-state lithium ion battery and manufacturing method thereof

Abstract

The invention provides a curved-surface solid-state lithium ion battery and a manufacturing method thereof, the manufacturing method is an electric field driving 3D printing method based on a five-axis mechanical platform, the five-axis mechanical platform is composed of a printing nozzle part moving in the X-axis direction, the Y-axis direction and the Z-axis direction and a part rotating in the A-axis direction and the C-axis direction, and high-precision electric field driving 3D printing is combined. The high-precision manufacturing of the conformal object on the curved-surface substrate can be realized, and the formed curved-surface solid-state lithium ion battery can be applied to the fields of Internet of Things, wearable electronic equipment and the like.

Description

Technical Field

[0001] The present invention belongs to the field of solid-state battery manufacturing, and in particular relates to a curved solid-state lithium-ion battery and a manufacturing method thereof. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] The manufacture of traditional lithium-ion batteries is based on the slurry coating process, which can mass-produce cylindrical or square batteries with fixed shapes. With the development of the Internet of Things and wearable electronic devices, the application scenarios of energy storage batteries have been further expanded, and the demand for curved batteries has increased. For example, if the battery is embedded in the casing of a smartphone, the space occupied by the battery can be greatly reduced, making the phone thinner and lighter. For another example, the battery can be combined with the frame of smart glasses, which serves as a structural component and can also provide energy for the operation of the smart glasses. The above requirements all require that the battery shape is not limited to the current cylindrical or square shape, but can fit perfectly with the actual object, that is, a curved battery. However, the current traditional slurry coating process cannot realize the manufacture of curved batteries.

[0004] In addition, battery safety is also a key point to consider. The organic liquid electrolytes used in traditional lithium-ion batteries have potential safety issues, such as flammability, poor thermal stability, and liquid leakage. In order to solve the inherent safety defects of traditional batteries and further improve the energy density and service life of batteries, using solid electrolytes to replace traditional organic liquid electrolytes, namely solid-state lithium-ion batteries, is an effective solution. Solid electrolytes have many advantages over traditional organic liquid electrolytes: (i) they are non-flammable, high-temperature stable, and non-volatile, eliminating the potential risk of combustion or explosion of organic liquid electrolytes; (ii) wide electrochemical window, which can be better compatible with high-voltage positive electrode materials, thereby greatly improving energy density; (iii) when using metallic lithium as the negative electrode, the high mechanical stiffness and adjustable elastic modulus of the solid electrolyte can inhibit the dendrite growth of the metallic lithium negative electrode.

[0005] In summary, based on the needs of the future Internet of Things and wearable electronic devices, it is extremely urgent to develop curved solid-state lithium-ion batteries, which requires innovation in battery manufacturing processes. 3D printing, also known as additive manufacturing, is a strategic new technology for manufacturing complex three-dimensional objects from the bottom up. This technology can customize the printing of micro-nano structures of different dimensions and shapes according to needs and application scenarios, thereby effectively solving the manufacturing problems of the above-mentioned curved solid-state batteries. Summary of the invention

[0006] In order to solve the above problems, the present invention proposes a curved solid-state lithium-ion battery and a manufacturing method thereof. The present invention proposes an electric field-driven 3D printing technology based on a five-axis mechanical platform to realize the manufacture of conformal curved batteries on any curved surface. The 3D printing technology adopted by the present invention is not a traditional simple extrusion 3D printing, but a high-precision 3D printing driven by an electric field. The printing needle component is connected to a high-voltage power supply, and an electric field is formed between the needle and the substrate under the action of electrostatic force. The extruded ink is simultaneously subjected to the electric field force, back pressure, and surface tension at the nozzle tip. When the electric field force exceeds the surface tension, a Taylor cone jet is formed at the ink tip, which can be sprayed and deposited onto the printing substrate with higher precision.

[0007] The proposed curved battery is composed of a lithium titanate negative electrode, a solid electrolyte, a lithium iron phosphate positive electrode and an outer packaging layer, which is obtained by 3D printing and assembly layer by layer. The shape of the curved battery can be arbitrarily changed according to the shape of the printed substrate, and it fits perfectly with the substrate shape.

[0008] According to some embodiments, the present invention adopts the following technical solutions:

[0009] A curved solid-state lithium-ion battery and a manufacturing method thereof, comprising the following steps:

[0010] A certain amount of polyimide is dispersed in dimethylacetamide, heated for a certain period of time in a sealed state, and then cooled to room temperature to obtain a uniform viscous polyimide solution;

[0011] Using an electric field to drive 3D printing of the polyimide solution to obtain a thin film polyimide layer conforming to the substrate, and heating to remove the solvent dimethylacetamide to obtain a polyimide film substrate;

[0012] After the lithium titanate negative electrode active material is mixed with the conductive carbon and the binder and ground evenly, N-methylpyrrolidone is added and wet-ground until uniform to obtain a viscous printable negative electrode ink;

[0013] On the polyimide film, the negative electrode ink is 3D printed using an electric field to form a negative electrode, and then dried;

[0014] Dispersing polyethylene oxide, lithium salt and oxide inorganic solid electrolyte in acetonitrile, stirring for a certain period of time in an oil bath heating, and obtaining a uniform, viscous printing ink;

[0015] Using electric field driven 3D printing technology, printing the printing ink on the negative electrode according to a preset circular path to form an electrolyte membrane;

[0016] The lithium iron phosphate positive electrode active material is mixed with the conductive carbon and the binder and ground evenly, and then N-methylpyrrolidone is added and wet-ground until uniform to obtain a viscous printable positive electrode ink;

[0017] Using an electric field to drive 3D printing of the positive electrode ink to form a positive electrode, and drying it;

[0018] A uniform viscous polyimide solution is prepared, and a polyimide layer is printed on top of the printed positive electrode along the shape of the device to complete the packaging of the solid-state lithium-ion battery.

[0019] As an optional implementation, the mass fraction of polyimide in the polyimide solution is 10% to 30%, the heating temperature is 60-90° C., and the heating time is 1-6 hours.

[0020] As an optional implementation, a five-axis mechanical platform is used for electric field driven 3D printing. During the printing of the polyimide substrate, the printing speed is 5-20 mm / s, the air compressor provides an air pressure of 100-200 kPa, and the number of printing layers is 1;

[0021] The printing needle diameter is 100-400μm, the obtained printing height is 50-250μm, and the printing line width is 5-100μm.

[0022] As an optional embodiment, during the printing of the polyimide substrate, the voltage introduced by the print head is 800-1500V.

[0023] As an optional implementation manner, the mass fraction of the lithium titanate is 50-90%, the mass fraction of the conductive carbon is 5-30%, and the mass fraction of the binder is 5-20%.

[0024] As a further feature, the conductive carbon is a combination of one or more of Super P, Ketjen black, graphene and carbon nanotubes, and the binder is polyvinylidene fluoride.

[0025] As a further feature, the drying temperature is 60-120° C., and the drying time is 1-24 hours.

[0026] As an optional implementation, during the printing of the lithium titanate negative electrode, the printing speed is 5-20 mm / s, the air compressor provides an air pressure of 100-200 kPa, and the number of printing layers is 1-5;

[0027] The printing needle diameter is 100-400μm, the obtained printing height is 50-250μm, and the printing line width is 5-100μm.

[0028] As an optional implementation, during the printing of lithium titanate negative electrode, the voltage introduced by the printing nozzle is 800-1500V.

[0029] As an optional embodiment, after polyethylene oxide, lithium salt and oxide inorganic solid electrolyte are dispersed in acetonitrile, they are stirred for a certain period of time in an oil bath heating until the electrolyte printing ink has a uniform texture.

[0030] As a further example, the lithium salt is one or a combination of lithium perchlorate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, lithium hexafluorophosphate, and lithium tetrafluoroborate.

[0031] As a further example, the oxide inorganic solid electrolyte material is garnet-type Li7La3Zr2O 12 (LLZO), NAS I CON type Li 1.3 A l 0.3 T i 1.7 (PO4)3(LATP) and NAS I CON type Li 1.5 A l 0.5 Ge 1.5 One of (PO4)3(LAGP).

[0032] As a further step, the amount of polyethylene oxide and lithium salt is controlled between EO and Li + The molar ratio is 10:1 to 40:1.

[0033] As a further feature, the inorganic solid electrolyte is added in an amount of 5 to 10 wt % of the total mass of the composite solid electrolyte.

[0034] As a further example, the heating temperature is 40-60°C; and the stirring time is 6-24h.

[0035] As an optional embodiment, during the printing of the electrolyte membrane, the printing speed is 5-20 mm / s, the air compressor provides an air pressure of 100-200 kPa, and the number of printing layers is 1;

[0036] The printing needle diameter is 100-400μm, the obtained printing height is 50-250μm, and the printing line width is 5-100μm.

[0037] As an optional embodiment, during the printing of the electrolyte membrane, the voltage introduced by the print head is 800-1500V.

[0038] As an optional embodiment, the drying temperature is 40-60° C. and the drying time is set to 24-48 hours.

[0039] As an optional implementation manner, the mass fraction of the lithium iron phosphate is 50-90%, the mass fraction of the conductive carbon is 5-30%, and the mass fraction of the binder is 5-20%.

[0040] As a further feature, the conductive carbon is a combination of one or more of Super P, Ketjen black, graphene and carbon nanotubes, and the binder is polyvinylidene fluoride.

[0041] As a further feature, the drying temperature is 60-120° C., and the drying time is 1-24 hours.

[0042] As an optional implementation, during the printing of the lithium iron phosphate positive electrode, the printing speed is 5-20 mm / s, the air compressor provides an air pressure of 100-200 kPa, and the number of printing layers is 1-5;

[0043] The printing needle diameter is 100-400μm, the obtained printing height is 50-250μm, and the printing line width is 5-100μm.

[0044] As an optional implementation, during the printing of the lithium iron phosphate positive electrode, the voltage introduced by the print head is 800-1500V.

[0045] A curved solid-state lithium-ion battery is obtained by the above method and is composed of a substrate, a lithium titanate negative electrode, a solid electrolyte, a lithium iron phosphate positive electrode and a polyimide packaging layer stacked together.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] The electric field driven 3D printing manufacturing process based on a five-axis mechanical platform proposed in the present invention solves the problem of curved battery manufacturing that cannot be achieved by the traditional lithium-ion battery slurry coating method, and realizes the efficient manufacturing of curved batteries of any shape that is conformal to the substrate.

[0048] Compared with traditional 3D printing technology, the electric field driven jet micro-nano 3D printing technology adopted in the present invention has the advantages of high resolution and high printing accuracy, and can significantly improve the surface flatness of the printed curved battery.

[0049] The present invention can change the printing path according to actual application requirements to achieve rapid customization of curved solid-state lithium-ion batteries of different shapes and sizes, and is very suitable for the manufacture of power sources for personalized electronic products.

[0050] The curved solid-state lithium-ion battery obtained by the present invention has the advantage of high safety. At the same time, it can fit the shape of the structural components of electronic products during use, or even replace the structural components, playing the dual role of energy supply and load bearing, greatly reducing the size and weight of electronic products.

[0051] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] The accompanying drawings in the specification, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0053] Figure 1 The present invention is a process flow chart of manufacturing curved solid-state lithium-ion batteries by electric field driven 3D printing based on a five-axis mechanical platform in one embodiment;

[0054] Figure 2 The diagram is a schematic diagram of the principle of electric field driven 3D printing adopted in one embodiment.

[0055] Figure 3 It is a schematic diagram of the curved battery printing process and the solid-state lithium-ion battery structure. DETAILED DESCRIPTION

[0056] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0057] It should be noted that the following detailed descriptions are all illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0058] Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0059] In the absence of conflict, the embodiments in this application and the features in the embodiments may be combined with each other.

[0060] Embodiment 1

[0061] A curved solid-state lithium-ion battery and a manufacturing method thereof, wherein the curved solid-state lithium-ion battery structure is composed of a substrate, a lithium titanate negative electrode, a solid electrolyte, a lithium iron phosphate positive electrode and a polyimide encapsulation layer. The curved battery refers to a battery that conformally fits with the substrate on any non-flat plane.

[0062] The manufacturing method includes:

[0063] S1, polyimide substrate printing.

[0064] Disperse 10g of polyimide into 90g of dimethylacetamide and heat at 60℃ for 3h in a sealed state. After heating, cool to room temperature to obtain a uniform viscous polyimide solution;

[0065] The polyimide solution is loaded into the printing barrel, and electric field-driven 3D printing is completed on a five-axis mechanical platform to obtain a thin film polyimide layer that conforms to the substrate. Finally, the solvent dimethylacetamide is removed by high-temperature heating to obtain a polyimide film substrate. The printing speed is 5mm / s, the air compressor provides an air pressure of 100kpa, and the number of printing layers is 1. The printing needle diameter is 100μm, and the set printing height is 50μm. The voltage introduced by the print nozzle is 1000V.

[0066] S2, lithium titanate negative electrode printing

[0067] The lithium titanate negative electrode active material is mixed with Ketjen black and polyvinylidene fluoride in a mass ratio of 7:2:1 and ground evenly, and then N-methylpyrrolidone is added and wet grinding is continued until uniform to obtain a viscous printable negative electrode ink.

[0068] The ink was loaded into the printing cartridge, and the electric field-driven 3D printing based on the five-axis mechanical platform was completed on the polyimide film in the same manner as above. Subsequently, the printed negative electrode was dried at 80°C for 12 hours to remove the solvent.

[0069] During the printing of lithium titanate negative electrode, the printing speed is 10mm / s, the air compressor provides an air pressure of 200kpa, the number of printing layers is 1, the printing needle diameter is 100μm, and the obtained printing height is 50μm. The voltage introduced by the printing nozzle is 1000V.

[0070] S3, solid electrolyte printing

[0071] S31 disperses polyethylene oxide (PEO), lithium salt and oxide inorganic solid electrolyte in acetonitrile, stirs for a certain period of time in an oil bath heating, and obtains a uniform and viscous printing ink.

[0072] In some embodiments, the lithium salt in step S31 is one or a combination of lithium perchlorate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, lithium hexafluorophosphate, and lithium tetrafluoroborate.

[0073] Furthermore, in some embodiments, the inorganic solid electrolyte material in step S31 is garnet-type Li7La3Zr2O 12 (LLZO), NAS I CON type Li 1.3 A l 0.3 T i 1.7 (PO4)3(LATP) and NAS I CON type Li 1.5 Al 0.5 Ge 1.5 One of (PO4)3(LAGP).

[0074] Further, in some embodiments, the amount of polyPEO and lithium salt in step S31 is controlled to be between EO and Li + The molar ratio is 20:1.

[0075] Furthermore, in some embodiments, the addition ratio of the inorganic solid electrolyte in step S31 is 5 wt % of the total mass of the composite solid electrolyte.

[0076] Furthermore, in some embodiments, the heating temperature in step S31 is 40°C.

[0077] Furthermore, in some embodiments, the stirring time in step S31 is 6-24 hours.

[0078] S32, the solid electrolyte printing ink prepared in S31 is loaded into the printing barrel, and the electrolyte membrane is printed according to a preset circular path using electric field driven jet 3D printing technology. The printing speed is 5 mm / s, the air compressor provides an air pressure of 100 kPa, and the number of printing layers is 1.

[0079] S4, lithium iron phosphate cathode printing

[0080] The lithium iron phosphate positive electrode active material is mixed with Ketjen black and polyvinylidene fluoride in a mass ratio of 7:2:1 and ground evenly, and then N-methylpyrrolidone is added and wet grinding is continued until uniform to obtain a viscous printable negative electrode ink.

[0081] The ink was loaded into the printing cartridge, and the electric field-driven 3D printing based on the five-axis mechanical platform was completed on the polyimide film in the same manner as above. Subsequently, the printed positive electrode was dried at 60°C for 6 hours to remove the solvent.

[0082] During the printing of lithium iron phosphate cathode, the printing speed was 10 mm / s, the air compressor provided an air pressure of 200 kPa, the number of printing layers was 1, the printing needle diameter was 100 μm, and the obtained printing height was 50 μm. The voltage introduced by the print head was 1000 V.

[0083] S5, polyimide encapsulation layer

[0084] Similar to the above step S1, a uniform viscous polyimide solution is prepared, and a polyimide layer is printed on top of the printed positive electrode along the shape of the device to complete the packaging of the solid-state lithium-ion battery.

[0085] In some embodiments, the electric field driven 3D printing manufacturing technology based on the five-axis mechanical platform can realize the manufacturing of conformal solid-state lithium-ion batteries on any curved surface. The size of the battery can be adjusted as needed.

[0086] This embodiment uses electric field driven jet micro-nano 3D printing technology and adopts a five-axis mechanical platform. The platform is divided into two parts, namely the printing nozzle component that moves along the three axes of X, Y, and Z and the rotating moving component along the A and C axes. During the printing process, the printing nozzle discharges downward and is perpendicular to the tangent direction of the base surface. The printed object is conformal to the base surface. Figure 2 As shown, the print head is connected to a high-voltage power supply, and the print head with a positive dot generates electrostatic induction with the printing substrate, forming an electric field between the two. During the printing process, the ink curved liquid surface at the tip of the nozzle is simultaneously affected by the electric field force, surface tension and viscosity, and gradually forms a Taylor cone. When the electric field force exceeds the surface tension, the printing ink forms an extremely fine jet from the top of the Taylor cone and deposits on the substrate. Compared with traditional 3D printing, electric field-driven jet 3D printing technology can significantly improve printing accuracy, thereby obtaining solid-state curved lithium-ion batteries with low surface roughness.

[0087] Embodiment 2

[0088] A curved solid-state lithium-ion battery and a manufacturing method thereof are based on an electric field-driven 3D printing technology of a five-axis mechanical platform. The five-axis mechanical platform consists of a printing nozzle component that moves along three axes of X, Y, and Z and a rotational moving component along the A and C axes. Combined with high-precision electric field-driven 3D printing, high-precision manufacturing of conformal objects on curved substrates can be achieved.

[0089] The specific process is as follows Figure 3 As shown, including:

[0090] S1, polyimide substrate printing.

[0091] Disperse 20g of polyimide into 80g of dimethylacetamide, heat at 80℃ for 5h in a sealed state, and cool to room temperature to obtain a uniform viscous polyimide solution;

[0092] The polyimide solution is loaded into the printing barrel, and electric field-driven 3D printing is completed on a five-axis mechanical platform to obtain a thin film polyimide layer that conforms to the substrate. Finally, the solvent dimethylacetamide is removed by high-temperature heating to obtain a polyimide film substrate. The printing speed is 10mm / s, the air compressor provides an air pressure of 150kpa, and the number of printing layers is 1. The printing needle diameter is 250μm, and the set printing height is 100μm. The voltage introduced by the print nozzle is 1200V.

[0093] S2, lithium titanate negative electrode printing

[0094] The lithium titanate negative electrode active material is mixed with Ketjen black and polyvinylidene fluoride in a mass ratio of 7:2:1 and ground evenly, and then N-methylpyrrolidone is added and wet grinding is continued until uniform to obtain a viscous printable negative electrode ink.

[0095] The ink was loaded into the printing cartridge, and the electric field-driven 3D printing based on the five-axis mechanical platform was completed on the polyimide film in the same manner as above. Subsequently, the printed negative electrode was dried at 80°C for 12 hours to remove the solvent.

[0096] During the printing of lithium titanate negative electrode, the printing speed is 10mm / s, the air compressor provides an air pressure of 150kpa, and the number of printing layers is 3. The printing needle diameter is 250μm, and the set printing height is 100μm. The voltage introduced by the printing nozzle is 1200V.

[0097] S3, solid electrolyte printing

[0098] S31 disperses polyethylene oxide (PEO), lithium salt and oxide inorganic solid electrolyte in acetonitrile, stirs for a certain period of time in an oil bath heating, and obtains a uniform and viscous printing ink.

[0099] In some embodiments, the lithium salt in step S31 is one or a combination of lithium perchlorate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, lithium hexafluorophosphate, and lithium tetrafluoroborate.

[0100] Furthermore, in some embodiments, the inorganic solid electrolyte material in step S31 is garnet-type Li7La3Zr2O 12 (LLZO), NAS I CON type Li 1.3 A l 0.3 T i 1.7 (PO4)3(LATP) and NAS I CON type Li 1.5 Al 0.5 Ge 1.5 One of (PO4)3(LAGP).

[0101] Further, in some embodiments, the amount of polyPEO and lithium salt in step S31 is controlled to be between EO and Li + The molar ratio is 20:1.

[0102] Furthermore, in some embodiments, the addition ratio of the inorganic solid electrolyte in step S31 is 8 wt % of the total mass of the composite solid electrolyte.

[0103] Furthermore, in some embodiments, the heating temperature in step S31 is 50°C.

[0104] Furthermore, in some embodiments, the stirring time in step S31 is 12 hours.

[0105] S32, the solid electrolyte printing ink prepared in S31 is loaded into the printing barrel, and the electrolyte membrane is printed according to a preset circular path using electric field driven jet 3D printing technology. The printing speed is 5 mm / s, the air compressor provides an air pressure of 100 kPa, and the number of printing layers is 1.

[0106] S4, lithium iron phosphate cathode printing

[0107] The lithium iron phosphate positive electrode active material is mixed with Ketjen black and polyvinylidene fluoride in a mass ratio of 7:2:1 and ground evenly, and then N-methylpyrrolidone is added and wet grinding is continued until uniform to obtain a viscous printable negative electrode ink.

[0108] The ink was loaded into the printing cartridge, and the electric field-driven 3D printing based on the five-axis mechanical platform was completed on the polyimide film in the same manner as above. Subsequently, the printed positive electrode was dried at 80°C for 12 hours to remove the solvent.

[0109] During the printing of lithium iron phosphate cathode, the printing speed is 10mm / s, the air compressor provides an air pressure of 150kpa, and the number of printing layers is 3. The printing needle diameter is 250μm, and the set printing height is 100μm. The voltage introduced by the print head is 1200V.

[0110] S5, polyimide encapsulation layer

[0111] Similar to the above step S1, a uniform viscous polyimide solution is prepared, and a polyimide layer is printed on top of the printed positive electrode along the shape of the device to complete the packaging of the solid-state lithium-ion battery.

[0112] Embodiment 3

[0113] A curved solid-state lithium-ion battery and a manufacturing method thereof, comprising:

[0114] S1, polyimide substrate printing.

[0115] Disperse 30g of polyimide into 70g of dimethylacetamide, heat at 90℃ for 6h in a sealed state, and cool to room temperature to obtain a uniform viscous polyimide solution;

[0116] The polyimide solution is loaded into the printing barrel, and electric field-driven 3D printing is completed on a five-axis mechanical platform to obtain a thin film polyimide layer that conforms to the substrate. Finally, the solvent dimethylacetamide is removed by high-temperature heating to obtain a polyimide film substrate. The printing speed is 20mm / s, the air compressor provides an air pressure of 200kpa, and the number of printing layers is 1. The printing needle diameter is 400μm, and the set printing height is 250μm. The voltage introduced by the print nozzle is 1500V.

[0117] S2, lithium titanate negative electrode printing

[0118] The lithium titanate negative electrode active material is mixed with Ketjen black and polyvinylidene fluoride in a mass ratio of 8:1:1 and ground evenly, and then N-methylpyrrolidone is added and wet grinding is continued until uniform to obtain a viscous printable negative electrode ink.

[0119] The ink was loaded into the printing cartridge, and the electric field-driven 3D printing based on the five-axis mechanical platform was completed on the polyimide film in the same manner as above. Subsequently, the printed negative electrode was dried at 120°C for 24 hours to remove the solvent.

[0120] During the printing of lithium titanate negative electrode, the printing speed is 20mm / s, the air compressor provides an air pressure of 200kpa, and the number of printing layers is 5. The printing needle diameter is 400μm, and the set printing height is 250μm. The voltage introduced by the printing nozzle is 1500V.

[0121] S3, solid electrolyte printing

[0122] S31 disperses polyethylene oxide (PEO), lithium salt and oxide inorganic solid electrolyte in acetonitrile, stirs for a certain period of time in an oil bath heating, and obtains a uniform and viscous printing ink.

[0123] In some embodiments, the lithium salt in step S31 is one or a combination of lithium perchlorate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, lithium hexafluorophosphate, and lithium tetrafluoroborate.

[0124] Furthermore, in some embodiments, the inorganic solid electrolyte material in step S31 is garnet-type Li7La3Zr2O 12 (LLZO), NAS I CON type Li 1.3 A l 0.3 T i 1.7 (PO4)3(LATP) and NAS I CON type Li 1.5 Al 0.5 Ge 1.5 One of (PO4)3(LAGP).

[0125] Further, in some embodiments, the amount of polyPEO and lithium salt in step S31 is controlled to be between EO and Li + The molar ratio is 40:1.

[0126] Furthermore, in some embodiments, the addition ratio of the inorganic solid electrolyte in step S31 is 10 wt % of the total mass of the composite solid electrolyte.

[0127] Furthermore, in some embodiments, the heating temperature in step S31 is 60°C.

[0128] Furthermore, in some embodiments, the stirring time in step S31 is 24 hours.

[0129] S32, the solid electrolyte printing ink prepared in S31 is loaded into the printing barrel, and the electric field driven jet 3D printing technology is used to complete the printing of the electrolyte membrane according to the preset circular path. The printing speed is 20mm / s, the air compressor provides an air pressure of 200kpa, and the number of printing layers is 1. The printing needle diameter is 400μm, and the set printing height is 250μm. The voltage introduced by the printing nozzle is 1500V.

[0130] S4, lithium iron phosphate cathode printing

[0131] The lithium iron phosphate positive electrode active material is mixed with Ketjen black and polyvinylidene fluoride in a mass ratio of 7:2:1 and ground evenly, and then N-methylpyrrolidone is added and wet grinding is continued until uniform to obtain a viscous printable negative electrode ink.

[0132] The ink was loaded into the printing cartridge, and the electric field-driven 3D printing based on the five-axis mechanical platform was completed on the polyimide film in the same manner as above. Subsequently, the printed positive electrode was dried at 120°C for 24 hours to remove the solvent.

[0133] During the printing of lithium iron phosphate cathode, the printing speed is 20mm / s, the air compressor provides an air pressure of 200kpa, and the number of printing layers is 5. The printing needle diameter is 400μm, and the set printing height is 250μm. The voltage introduced by the print head is 1500V.

[0134] S5, polyimide encapsulation layer

[0135] Similar to the above step S1, a uniform viscous polyimide solution is prepared, and a polyimide layer is printed on top of the printed positive electrode along the shape of the device to complete the packaging of the solid-state lithium-ion battery.

[0136] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made by those skilled in the art within the spirit and principle of the present invention without creative labor shall be included in the protection scope of the present invention.

Claims

1. A curved solid-state lithium-ion battery and a method for manufacturing the same, characterized in that: The following steps are involved: A certain amount of polyimide is dispersed in dimethylacetamide, heated for a certain period of time in a sealed state, and then cooled to room temperature to obtain a uniform viscous polyimide solution; Using an electric field to drive 3D printing of the polyimide solution to obtain a thin film polyimide layer conforming to the substrate, and heating to remove the solvent dimethylacetamide to obtain a polyimide film substrate; The lithium titanate negative electrode active material is mixed with the conductive carbon and the binder and ground evenly, and then N-methylpyrrolidone is added and wet-ground until uniform to obtain a viscous printable negative electrode ink; On the polyimide film, the negative electrode ink is 3D printed using an electric field to form a negative electrode, and then dried; Dispersing polyethylene oxide, lithium salt and oxide inorganic solid electrolyte in acetonitrile, stirring for a certain period of time in an oil bath heating, and obtaining a uniform, viscous printing ink; Using electric field driven 3D printing technology, printing the printing ink on the negative electrode according to a preset circular path to form an electrolyte membrane; The lithium iron phosphate positive electrode active material is mixed with the conductive carbon and the binder and ground evenly, and then N-methylpyrrolidone is added and wet-ground until uniform to obtain a viscous printable positive electrode ink; Using an electric field to drive 3D printing of the positive electrode ink to form a positive electrode, and drying it; A uniform viscous polyimide solution is prepared, and a polyimide layer is printed on top of the printed positive electrode along the shape of the device to complete the packaging of the solid-state lithium-ion battery.

2. A curved solid-state lithium-ion battery and a method for manufacturing the same as claimed in claim 1, characterized in that: The mass fraction of polyimide in the polyimide solution is 10% to 30%; Or, the drying temperature is 60-120° C., and the drying time is 1-24 h; The heating temperature is 40-60°C; the stirring time is 6-24h.

3. A curved solid-state lithium-ion battery and a method for manufacturing the same as claimed in claim 1, characterized in that: Using a five-axis mechanical platform for electric field driven 3D printing, during the printing of the polyimide substrate, the printing speed is 5-20mm / s, the air compressor provides an air pressure of 100-200kpa, and the number of printing layers is 1; The print tip diameter is 100-400μm, the print height is 50-250μm, and the print line width is 5-100μm; During the printing of the polyimide substrate, the voltage introduced by the print head is 800-1500V.

4. A curved solid-state lithium-ion battery and a method for manufacturing the same as claimed in claim 1, characterized in that: The mass fraction of the lithium titanate is 50-90%, the mass fraction of the conductive carbon is 5-30%, and the mass fraction of the binder is 5-20%; The conductive carbon is a combination of one or more of Super P, Ketjen black, graphene and carbon nanotubes, and the binder is polyvinylidene fluoride.

5. A curved solid-state lithium-ion battery and a method for manufacturing the same as claimed in claim 1, characterized in that: During the printing of lithium titanate negative electrode, the printing speed is 5-20mm / s, the air compressor provides an air pressure of 100-200kpa, and the number of printing layers is 1-5; The print tip diameter is 100-400μm, the print height is 50-250μm, and the print line width is 5-100μm; During the printing process of lithium titanate negative electrode, the voltage introduced by the printing nozzle is 800-1500V.

6. A curved solid-state lithium-ion battery and a method for manufacturing the same as claimed in claim 1, characterized in that: The lithium salt is one or a combination of lithium perchlorate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethylsulfonyl)imide, lithium hexafluorophosphate, and lithium tetrafluoroborate; The oxide inorganic solid electrolyte material is garnet-type Li7La3Zr2O 12 、NASICON type Li 1.3 Al 0.3 Ti 1.7 (PO4)3 and NAS ICON type Li 1.5 Al 0.5 Ge 1.5 One of (PO4)3; Or further, the amount of polyethylene oxide and lithium salt is controlled at EO and Li + The molar ratio is 10:1 to 40:1; The addition ratio of the inorganic solid electrolyte is 5-10wt% of the total mass of the composite solid electrolyte.

7. A curved solid-state lithium-ion battery and a method for manufacturing the same as claimed in claim 1, characterized in that: During the printing of the electrolyte membrane, the printing speed is 5-20 mm / s, the air compressor provides an air pressure of 100-200 kPa, and the number of printing layers is 1; The print tip diameter is 100-400μm, the print height is 50-250μm, and the print line width is 5-100μm; During the printing of the electrolyte membrane, the voltage introduced by the print head is 800-1500V.

8. A curved solid-state lithium-ion battery and a method for manufacturing the same as claimed in claim 1, characterized in that: The mass fraction of the lithium iron phosphate is 50-90%, the mass fraction of the conductive carbon is 5-30%, and the mass fraction of the binder is 5-20%; The conductive carbon is a combination of one or more of Super P, Ketjen black, graphene and carbon nanotubes, and the binder is polyvinylidene fluoride.

9. A curved solid-state lithium-ion battery and a method for manufacturing the same as claimed in claim 1, characterized in that: During the printing of lithium iron phosphate cathode, the printing speed is 5-20mm / s, the air compressor provides an air pressure of 100-200kpa, and the number of printing layers is 1-5; The print tip diameter is 100-400μm, the print height is 50-250μm, and the print line width is 5-100μm; During the printing process of lithium iron phosphate positive electrode, the voltage introduced by the printing nozzle is 800-1500V.

10. A curved solid-state lithium-ion battery, characterized in that: The invention is prepared by the manufacturing method according to any one of claims 1 to 9, and is composed of a substrate, a lithium titanate negative electrode, a solid electrolyte, a lithium iron phosphate positive electrode and a polyimide encapsulation layer stacked together.

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