Method for 3D printing of solid-state battery and prepared solid-state battery

Abstract

The invention relates to the technical field of solid-state batteries, in particular to a method for 3D printing of a solid-state battery and the prepared solid-state battery. The method for 3D printing of the solid-state battery comprises the following steps: integrally printing a whole solid-state battery cell by adopting 3D printing to obtain a solid-state battery cell block; then laminating the solid-state battery cell blocks; wherein the solid-state battery core block sequentially comprises a first bipolar current collector layer, a first fiberization binder layer, a positive electrode layer, a solid-state electrolyte layer, a negative electrode layer, a second fiberization binder layer and a second bipolar current collector layer from bottom to top.

Description

Technical Field

[0001] The present invention relates to the technical field of solid-state batteries, and in particular to a method for 3D printing a solid-state battery and a solid-state battery produced therefrom. Background Art

[0002] All-solid-state batteries refer to the use of solid electrolytes to replace the electrolyte and separator of traditional lithium-ion batteries, while matching high-capacity positive and negative electrodes to intrinsically improve the safety and energy density of the battery. The emerging 3D printing technology can customize complex three-dimensional structures of electrodes and solid electrolyte structures according to demand, which can improve the performance of solid-state batteries.

[0003] However, the current 3D printing technology for preparing lithium-ion batteries is relatively complicated. Usually, the positive and negative electrodes are printed separately and then assembled into batteries with solid electrolytes in a glove box. The process is cumbersome and time-consuming, and cannot fully utilize the advantages of 3D printing.

[0004] In the prior art, patent application CN 115224369 A designs convex and concave features at the interface between the electrode and the solid electrolyte to increase the interface contact area. The positive electrode slurry is coated at the interface between the positive electrode and the solid electrolyte to improve the interface wettability. The positive electrode and the solid electrolyte are formed by an indirect 3D printing process to achieve batch manufacturing; the positive electrode and the electrolyte are densified by sintering to improve the ionic conductivity. However, it still prints the positive and negative electrodes and the solid electrolyte separately, and then assembles them, which reduces production efficiency.

[0005] Therefore, although the prior art has disclosed the use of 3D printing methods to prepare solid-state batteries, existing applications cannot take into account both production efficiency and battery performance, and there is still room for further improvement. At the same time, the traditional dry electrode process usually premixes the active material, conductive agent, and binder and then fiberizes the binder through long-term high-speed stirring and shearing. This method not only has low fiberization efficiency, but also long-term high-speed shearing will also destroy the surface structure of the active material with a coating layer such as carbon, affecting the material performance. Summary of the invention

[0006] The present invention provides a method for 3D printing a solid-state battery and a solid-state battery prepared therefrom, so as to solve the defect that the production efficiency and battery performance cannot be taken into account when the 3D printing method is used to prepare solid-state batteries in the prior art; at the same time, the problem of low dry electrode fiberization efficiency and destructive effect on active materials is overcome, and the advantages of 3D printing are fully utilized.

[0007] In a first aspect, the present invention provides a method for 3D printing solid-state batteries, comprising: using 3D printing to print the entire solid-state battery cell in an integrated manner to obtain a solid-state battery cell block; and then laminating the solid-state battery cell block; wherein the solid-state battery cell block includes, from bottom to top, a first bipolar current collector layer, a first fiberized binder layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, a second fiberized binder layer, and a second bipolar current collector layer.

[0008] According to a method for 3D printing solid-state batteries provided by the present invention, the raw material of the first fiberized binder layer and the raw material of the second fiberized binder layer are independently and differently fiberized binders, and the binder includes one or more of polytetrafluoroethylene, polyvinyl pyrrolidone and polyvinylidene fluoride; the fiberization includes: high-speed shearing of a high mixer and air flow crushing of an air pulverizer.

[0009] According to the present invention, a method for 3D printing solid-state batteries comprises: when 3D printing solid-state batteries, each 3D printing nozzle corresponds to a raw material, and multiple layers are printed simultaneously; preferably, when 3D printing is performed, from bottom to top, first print the first bipolar current collector layer, and 0.5 to 2 minutes later print the positive electrode layer on the first bipolar current collector layer; then 0.5 to 2 minutes later print the first fibrous binder layer on the positive electrode layer; then 0.5 to 2 minutes later print the solid electrolyte layer on the first fibrous binder layer; then 0.5 to 2 minutes later print the negative electrode layer on the solid electrolyte layer; then 0.5 to 2 minutes later print the second fibrous binder layer on the negative electrode layer; then 0.5 to 2 minutes later print the second bipolar current collector layer on the second fibrous binder layer, so as to achieve simultaneous printing of multiple layers, and a battery unit is obtained after the printing is completed.

[0010] According to a method for 3D printing a solid-state battery provided by the present invention, the lamination includes a roller pressing or isostatic pressing process, and the lamination pressure is greater than 200 MPa.

[0011] According to a method for 3D printing a solid-state battery provided by the present invention, during the 3D printing process, a single layer rolling is performed while printing each layer; preferably, the pressure of the single layer rolling is 5-15 MPa.

[0012] According to a method for 3D printing solid-state batteries provided by the present invention, the 3D printing process includes one or more of a binder jet printing process, a fused deposition printing process and a selective laser sintering printing process; preferably, the positive electrode layer, the negative electrode layer, the first fiberized binder layer and the second fiberized binder layer are printed using the binder jet printing process.

[0013] According to a method for 3D printing a solid-state battery provided by the present invention, the raw material of the first bipolar current collector layer and the raw material of the second bipolar current collector layer independently, identically or differently include stainless steel foil and / or aluminum-copper composite foil.

[0014] According to a method for 3D printing solid-state batteries provided by the present invention, the raw materials of the positive electrode layer include a positive electrode active material and a conductive agent; preferably, the positive electrode active material includes lithium iron phosphate, lithium cobalt oxide, lithium nickel manganese oxide, ternary nickel cobalt manganese oxide or lithium-rich manganese base; the conductive agent includes one or more of super-p, conductive carbon black, acetylene black, graphene and carbon nanotubes.

[0015] According to a method for 3D printing solid-state batteries provided by the present invention, the raw materials of the solid electrolyte layer include one or more of oxide solid electrolytes, sulfide solid electrolytes and halide solid electrolytes; preferably, the oxide solid electrolyte includes one or more of lithium lanthanum zirconium oxide with garnet structure, lithium lanthanum zirconium tantalum oxide with garnet structure, lithium aluminum titanium phosphate with NASICON structure and lithium aluminum germanium phosphate with NASICON structure; the sulfide solid electrolyte includes one or more of lithium phosphorus sulfur chlorine, lithium germanium phosphorus sulfur, lithium tin phosphorus sulfur, lithium phosphorus sulfur and lithium tin sulfur; the halide solid electrolyte includes one or more of lithium indium chloride, lithium holmium chloride, lithium yttrium chloride, lithium scandium chloride and lithium erbium chloride.

[0016] According to a method for 3D printing a solid-state battery provided by the present invention, the raw material of the negative electrode includes one or more of graphite, silicon carbon, metallic lithium and lithium alloy.

[0017] According to a method for 3D printing a solid-state battery provided by the present invention, when the raw material of the solid electrolyte layer is an oxide solid electrolyte, sintering is further performed after the lamination, and the sintering temperature is 200-1000 degrees Celsius; and other solid electrolytes except the oxide solid electrolyte are not sintered after the lamination.

[0018] According to a method for 3D printing a solid-state battery provided by the present invention, the method for 3D printing a solid-state battery comprises: S1: preparing raw material powder of the first bipolar current collector layer, raw material powder of the first fiberized binder layer, raw material powder of the positive electrode layer, raw material powder of the solid electrolyte layer, raw material powder of the negative electrode layer, raw material powder of the second fiberized binder layer, and raw material powder of the second bipolar current collector layer; using 3D printing to print the entire solid-state battery cell in an integrated manner, during the 3D printing process, single-layer rolling is performed while printing each layer, and a solid-state battery cell block is obtained after printing; S2: laminating the solid-state battery cell blocks; S3: Cut the laminated solid battery cell blocks according to the battery cell size requirements; S4: Encapsulating the cut battery cells to obtain solid-state battery cells connected in series; When the raw material of the solid electrolyte layer is an oxide solid electrolyte, the cutting in S3 further includes sintering, and the sintering temperature is 200-1100 degrees Celsius.

[0019] In a second aspect, the present invention provides a solid-state battery, which is produced by the method of 3D printing solid-state batteries.

[0020] The method for 3D printing solid-state batteries and the solid-state batteries obtained by the present invention directly obtain solid-state battery cells including a bipolar current collector layer, a fiberized binder layer, a positive electrode layer, a solid electrolyte layer and a negative electrode layer by adopting multi-nozzle integrated printing. Not only can the manufacturing efficiency be greatly improved and batch manufacturing can be realized, but the bipolar current collectors can realize internal series connection of the solid-state battery, thereby increasing the output voltage and further increasing the energy density of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are 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.

[0022] Figure 1 This is a schematic diagram of a 3D printed solid-state battery provided in Example 1 of the present invention.

[0023] Figure 2 This is a process flow chart of 3D printing solid-state batteries provided in Example 3 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are 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.

[0025] At present, although the prior art has disclosed the use of 3D printing methods to prepare solid-state batteries, the existing applications cannot take into account both production efficiency and battery performance. The present invention finds that this is mainly because the prior art uses a single nozzle printing method to prepare solid-state batteries using a 3D printing method, and the positive electrode, negative electrode, and solid electrolyte are formed layer by layer; at the same time, in order to effectively wrap the electrode active material and the conductive agent, the electrode active material, the conductive agent, and the binder are usually premixed, and the obtained electrode material is sheared by long-term high-speed stirring to achieve binder fiberization. Although this can solve the problem of binder agglomeration, the overall fiberization of the electrode material will lead to low efficiency, and long-term high-speed shearing will also destroy the surface structure of the active material with a coating layer such as carbon, affecting the material performance.

[0026] In this regard, the present invention first discovered and proposed the integrated 3D printing of the negative electrode layer, solid electrolyte layer, positive electrode layer and bipolar current collector layer by multiple nozzles, which does not require further assembly and can significantly improve production efficiency; at the same time, the present invention can not only ensure that the binder is fully fiberized by pre-fiberizing the binder, but also only fiberize the binder in advance, which greatly improves the fiberization efficiency; ultimately effectively improving the battery performance.

[0027] Based on this, the present invention has the following technical solutions: In a first aspect, the present invention provides a method for 3D printing solid-state batteries, comprising: using 3D printing to print the entire solid-state battery cell in an integrated manner to obtain a solid-state battery cell block; and then laminating the solid-state battery cell block; wherein the solid-state battery cell block includes, from bottom to top, a first bipolar current collector layer, a first fiberized binder layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, a second fiberized binder layer, and a second bipolar current collector layer.

[0028] The present invention finds that by pre-fiberizing the binder separately and then using 3D printing to print the entire solid-state battery cell in an integrated manner, not only can the advantages of 3D printing be effectively utilized, but also the production efficiency and battery performance of the solid-state battery can be improved.

[0029] In the present invention, unlike the existing solid-state batteries which directly perform 3D printing on the solid current collector plate of the finished product, the present invention performs integrated custom printing on the current collector. The integrated printing process increases the composite effect of the electrode material and the current collector, thereby enhancing the performance of the battery cell.

[0030] In the specific implementation process, when the current collector is 3D printed, the structure of the current collector can be customized and a three-dimensional structure of the current collector can be designed. For example, for the negative electrode lithium metal, the three-dimensional structure is similar to the porous structure of a sponge, which can also alleviate the volume change problem caused by lithium deposition during the subsequent battery charging and discharging process.

[0031] According to a preferred embodiment provided by the present invention, the raw material of the first fiberized binder layer and the raw material of the second fiberized binder layer are independently and differently fiberized binders, and the binder includes one or more of polytetrafluoroethylene, polyvinyl pyrrolidone and polyvinylidene fluoride; the fiberization includes: high-speed shearing of a high mixer or air flow crushing of an air pulverizer.

[0032] More preferably, the fiberization is performed by high-speed shearing, wherein the shearing speed is 1000-2000 rpm.

[0033] According to a preferred embodiment provided by the present invention, when 3D printing a solid-state battery, each 3D printing nozzle corresponds to one raw material, and multiple layers are printed simultaneously.

[0034] In the present invention, printing multiple layers simultaneously does not mean that multiple layers start printing at the same time, but that the first bipolar current collector layer is printed from bottom to top, and the positive electrode layer is printed after waiting for 0.5 to 2 minutes, at which time the first bipolar current collector layer is still being printed; and so on, the subsequent first fibrous binder layer, solid electrolyte layer, negative electrode layer, second fibrous binder layer and second bipolar current collector layer are printed in sequence until the top second bipolar current collector layer is printed, that is, the integrated printing of a battery unit is completed.

[0035] In the present invention, multiple 3D printing nozzles are provided according to the performance requirements of the solid-state battery, and multiple battery cells can be printed simultaneously, which not only omits the subsequent further assembly but also further improves the battery performance.

[0036] According to a preferred embodiment provided by the present invention, when performing 3D printing, from bottom to top, the first bipolar current collector layer is printed first, and the positive electrode layer is printed on the first bipolar current collector layer 0.5 to 2 minutes later; then the first fiberized binder layer is printed on the positive electrode layer 0.5 to 2 minutes later; then the solid electrolyte layer is printed on the first fiberized binder layer 0.5 to 2 minutes later; then the negative electrode layer is printed on the solid electrolyte layer 0.5 to 2 minutes later; then the second fiberized binder layer is printed on the negative electrode layer 0.5 to 2 minutes later; then the second bipolar current collector layer is printed on the second fiberized binder layer 0.5 to 2 minutes later, to achieve simultaneous printing of multiple layers, and a battery unit is formed after printing is completed.

[0037] According to a preferred embodiment provided by the present invention, the lamination includes a roller pressing or isostatic pressing process, and the lamination pressure is greater than 200 MPa.

[0038] Further preferably, the lamination pressure is 200-500 MPa, specifically 200 MPa, 250 MPa, 300 MPa, 350 MPa, 400 MPa, 450 MPa or 500 MPa.

[0039] In the present invention, by controlling the lamination pressure within the above range, the density of the electrode and the solid electrolyte layer can be further improved, the grain gap can be reduced, and the ion transmission capacity of the battery cell can be improved; when the lamination pressure is low, it may cause the grain gap to be too large, thereby reducing the ion transmission capacity of the battery cell.

[0040] According to a preferred embodiment provided by the present invention, during the 3D printing process, single-layer rolling is performed while printing each layer; preferably, the pressure of the single-layer rolling is 5 to 15 MPa, for example, it can be 5 MPa, 6 MPa, 7 MPa, 8 MPa, 9 MPa, 10 MPa, 11 MPa, 12 MPa, 13 MPa, 14 MPa or 15 MPa.

[0041] In the present invention, the thickness of the first bipolar current collector layer and the second bipolar current collector layer are independently, the same or different, 5 to 20 microns; the thickness of the positive electrode layer can be adjusted according to demand, preferably 50 to 400 microns; the thickness of the solid electrolyte layer is 5 to 30 microns; the thickness of the negative electrode layer is determined according to the positive electrode capacity; specifically, the thickness of the silicon-carbon negative electrode is 70 to 400 microns, and the thickness of the lithium metal is 20 to 100 microns; the thickness of the first fiberized binder layer and the second fiberized binder layer are independently, the same or different, 1 to 20 microns.

[0042] According to a preferred embodiment provided by the present invention, the 3D printing process includes one or more of a binder jet printing process, a fused deposition printing process and a selective laser sintering printing process. Those skilled in the art may use the above-mentioned process technologies disclosed in the prior art to perform 3D printing, and the specific process technology scheme is not limited herein.

[0043] More preferably, the positive electrode layer, the negative electrode layer, the first fiberized binder layer and the second fiberized binder layer are formed by the binder jet printing process.

[0044] According to a preferred embodiment provided by the present invention, the raw material of the first bipolar current collector layer and the raw material of the second bipolar current collector layer independently, identically or differently include stainless steel foil and / or aluminum-copper composite foil.

[0045] According to a preferred embodiment provided by the present invention, the raw materials of the positive electrode layer include positive electrode active materials and conductive agents; preferably, the positive electrode active materials include lithium iron phosphate, lithium cobalt oxide, lithium nickel manganese oxide, ternary nickel cobalt manganese oxide or lithium-rich manganese base; the conductive agent includes one or more of super-p, conductive carbon black, acetylene black, graphene and carbon nanotubes.

[0046] According to a preferred embodiment provided by the present invention, the raw materials of the solid electrolyte layer include one or more of an oxide solid electrolyte, a sulfide solid electrolyte and a halide solid electrolyte; preferably, the oxide solid electrolyte includes one or more of lithium lanthanum zirconium oxide with a garnet structure, lithium lanthanum zirconium tantalum oxide with a garnet structure, lithium aluminum titanium phosphate with a NASICON structure and lithium aluminum germanium phosphate with a NASICON structure; the sulfide solid electrolyte includes one or more of lithium phosphorus sulfur chlorine, lithium germanium phosphorus sulfur, lithium tin phosphorus sulfur, lithium phosphorus sulfur and lithium tin sulfur; the halide solid electrolyte includes one or more of lithium indium chloride, lithium holmium chloride, lithium yttrium chloride, lithium scandium chloride and lithium erbium chloride.

[0047] According to a preferred embodiment provided by the present invention, the raw material of the negative electrode includes one or more of graphite, silicon carbon, metallic lithium and lithium alloy.

[0048] More preferably, the raw material of the negative electrode is metallic lithium and / or lithium alloy.

[0049] According to a preferred embodiment provided by the present invention, when the raw material of the solid electrolyte layer is an oxide solid electrolyte, sintering is further performed after the lamination, and the sintering temperature is 200~1000 degrees Celsius; and other solid electrolytes except the oxide solid electrolyte are not sintered after the lamination.

[0050] More preferably, the sintering time is 5 to 20 hours.

[0051] In the present invention, only when the raw material of the solid electrolyte layer is an oxide solid electrolyte, the lamination further includes sintering, which can make the positive electrode and the solid electrolyte layer more compact on the one hand, and make the positive and negative electrodes in closer contact with the solid electrolyte layer on the other hand, thereby improving ion conductivity, reducing the internal impedance of the battery, and improving the rate performance and energy density of the battery cell; other solid electrolytes can be directly cut and packaged after lamination.

[0052] According to a preferred embodiment provided by the present invention, the method for 3D printing a solid-state battery comprises: S1: preparing raw material powder of the first bipolar current collector layer, raw material powder of the first fiberized binder layer, raw material powder of the positive electrode layer, raw material powder of the solid electrolyte layer, raw material powder of the negative electrode layer, raw material powder of the second fiberized binder layer, and raw material powder of the second bipolar current collector layer; using 3D printing to print the entire solid-state battery cell in an integrated manner, during the 3D printing process, single-layer rolling is performed while printing each layer, and a solid-state battery cell block is obtained after printing; S2: laminating the solid-state battery cell blocks; S3: Cut the laminated solid battery cell blocks according to the battery cell size requirements; S4: Encapsulating the cut battery cells to obtain solid-state battery cells connected in series; When the raw material of the solid electrolyte layer is an oxide solid electrolyte, the cutting in S3 further includes sintering, and the sintering temperature is 200-1100 degrees Celsius.

[0053] In the present invention, the cutting refers to cutting the large battery cell horizontally and vertically to make it into completely separated independent battery cells. The production efficiency can be further improved by first manufacturing large-area battery cells and then cutting them according to needs.

[0054] In a second aspect, the present invention provides a solid-state battery, which is produced by the method of 3D printing solid-state batteries.

[0055] In order to further illustrate the technical solution of the present invention, the present invention provides the following specific embodiments and comparative examples.

[0056] Unless otherwise specified, the various raw materials used in the examples and comparative examples are commercially available conventional raw materials, and the technical means used are conventional means well known to those skilled in the art.

[0057] In the following embodiments, the thickness of the first bipolar current collector layer is 10 microns, the thickness of the second bipolar current collector layer is 6 microns, the thickness of the first fiberized binder layer is 10 microns, the thickness of the second fiberized binder layer is 8 microns, the thickness of the positive electrode layer is 150 microns, the thickness of the solid electrolyte layer is 20 microns; the thickness of the negative electrode is 100 microns.

[0058] In the following embodiments, the raw materials of the first bipolar current collector layer and the second bipolar current collector layer are both stainless steel current collector powder; the raw materials of the first fiberized binder layer and the second fiberized binder layer are both fiberized PTFE binder.

[0059] Example 1

[0060] This embodiment provides a solid-state battery, and the preparation method thereof includes: 1. Prepare stainless steel current collector powder, lithium iron phosphate positive electrode powder (including 70 parts of lithium iron phosphate powder and 2 parts of conductive carbon black), silicon carbon negative electrode powder (including 80 parts of silicon carbon powder and 1 part of conductive carbon black), lithium lanthanum zirconium oxygen solid electrolyte powder and fiberized PTFE binder for use.

[0061] The preparation method of the fiberized PTFE binder includes: high-speed shearing in a high mixer: wherein the shearing speed is 2000 rpm.

[0062] 2. Set up 13 3D printing nozzles to prepare 2 layers of solid-state battery core blocks: Nozzle 1 uses selective laser sintering technology to print the first bipolar current collector layer. After 1 to 2 minutes, Nozzle 2 uses binder injection molding technology to print the positive electrode layer on the first bipolar current collector layer. After 1 to 2 minutes, Nozzle 3 uses binder injection molding technology to print the fiberized binder layer on the positive electrode material layer. After 1 to 2 minutes, Nozzle 4 uses selective laser sintering technology to print the solid electrolyte layer on the fiberized binder layer. After 1 to 2 minutes, Nozzle 5 uses binder injection molding technology to print the negative electrode layer on the solid electrolyte layer. After 1 to 2 minutes, The rear nozzle 6 uses a binder injection molding process to print a fibrous binder layer on the negative electrode layer, repeating the above preparation unit to print a total of 13 layers, from bottom to top, in order: the first bipolar current collector layer, the positive electrode layer, the first fibrous binder layer, the solid electrolyte layer, the negative electrode layer, the second fibrous binder layer, the second bipolar current collector layer, the positive electrode layer, the first fibrous binder layer, the solid electrolyte layer, the negative electrode layer, the second fibrous binder layer and the second bipolar current collector layer, finally obtaining a solid-state battery cell block; when printing layer by layer, each layer is printed with a roller behind the nozzle, and rolling is performed immediately after printing, and the rolling pressure of a single layer is 10 MPa.

[0063] 3. The obtained solid-state battery cell block is subjected to isostatic pressing at a pressure of 300 MPa, a temperature of 25 degrees Celsius, and a time of 10 minutes; 4. Cut the block to obtain a solid-state battery cell with a size of 4 cm × 4 cm; 5. The obtained solid-state battery cell is sintered at 1000 degrees Celsius for 6 hours, and then the pole ears are welded on both sides of the solid-state battery cell and packaged with an aluminum-plastic film to obtain a finished battery cell.

[0064] Figure 1 is a schematic diagram of a 3D printed solid-state battery provided in this embodiment. It should be noted that: Figure 1 The figure does not show the complete printing of all solid-state batteries, but is just a schematic diagram of the process of printing to the first battery cell. Figure 2 This is a process flow chart of 3D printing solid-state batteries provided in this embodiment.

[0065] Example 2

[0066] This embodiment provides a solid-state battery, and the preparation method thereof includes: 1. Prepare stainless steel current collector powder, NCM811 positive electrode powder (including 80 parts of NCM811 powder and 2 parts of conductive carbon black), lithium indium metal alloy negative electrode powder (including 80 parts of silicon carbon powder and 2 parts of conductive carbon black), lithium phosphorus sulfur chlorine solid electrolyte powder and fiberized PTFE binder for use.

[0067] The preparation method of the fiberized PTFE binder includes: high-speed shearing in a high mixer: wherein the shearing speed is 2000 rpm.

[0068] 2. Set up 19 3D printing nozzles to prepare 2 layers of solid-state battery cells: Nozzle 1 uses selective laser sintering technology to print the first bipolar current collector layer. After 1 to 2 minutes, nozzle 2 uses binder injection molding technology to print the positive electrode layer on the first bipolar current collector layer. After 1 to 2 minutes, nozzle 3 uses binder injection molding technology to print the fiberized binder layer on the positive electrode material layer. After 1 to 2 minutes, nozzle 4 uses selective laser sintering technology to print the solid electrolyte layer on the fiberized binder layer. After 1 to 2 minutes, nozzle 5 uses binder injection molding technology to print the negative electrode layer on the solid electrolyte layer. After 1 to 2 minutes, nozzle 6 uses binder injection molding technology to print the negative electrode layer. Fiberized binder layer, repeat the above preparation unit, print a total of 19 layers, from bottom to top, in order: the first bipolar current collector layer, the positive electrode layer, the first fibrous binder layer, the solid electrolyte layer, the negative electrode layer, the second fibrous binder layer, the second bipolar current collector layer, the positive electrode layer, the first fibrous binder layer, the solid electrolyte layer, the negative electrode layer, the second fibrous binder layer, the second bipolar current collector layer, the positive electrode layer, the first fibrous binder layer, the solid electrolyte layer, the negative electrode layer, the second fibrous binder layer, the second bipolar current collector layer, the positive electrode layer, the first fibrous binder layer, the solid electrolyte layer, the negative electrode layer, the second fibrous binder layer and the second bipolar current collector layer, finally obtaining a solid-state battery cell block; when printing layer by layer, each layer is printed with a roller behind the nozzle, and rolling is performed immediately after printing, and the rolling pressure of a single layer is 10 MPa.

[0069] 3. The obtained solid-state battery cell block is subjected to isostatic pressing at a pressure of 500 MPa, a temperature of 25 degrees Celsius, and a time of 5 minutes; 4. Cut the block to obtain a solid-state battery cell with a size of 6 cm × 8 cm; 5. Weld the pole ears on both sides of the solid-state battery cell and encapsulate it with an aluminum-plastic film to obtain a finished battery cell.

[0070] Example 3

[0071] This embodiment provides a solid-state battery, the preparation of which is different from that of Embodiment 1 only in that no sintering step is included after cutting, and packaging is performed directly.

[0072] Example 4

[0073] This embodiment provides a solid-state battery, and the preparation method thereof is different from that of Embodiment 2 only in that sintering is performed after cutting, the sintering temperature is 200 degrees Celsius, the sintering time is 5 hours, and packaging is performed after sintering.

[0074] Example 5

[0075] This embodiment provides a solid-state battery, and the preparation method thereof is different from that of Embodiment 2 only in that the lamination pressure is 100 MPa.

[0076] Example 6

[0077] This embodiment provides a solid-state battery, and the preparation method thereof is different from that of Embodiment 2 only in that: during layer-by-layer printing, no single-layer rolling is performed.

[0078] Comparative Example 1 (Compared with Example 2)

[0079] This comparative example provides a solid-state battery, and its preparation method comprises the following steps: 1. Prepare stainless steel current collector powder, NCM811 positive electrode powder (including 80 parts of NCM811 powder and 2 parts of conductive carbon black), lithium indium metal alloy negative electrode powder (including 80 parts of silicon carbon powder and 2 parts of conductive carbon black), lithium phosphorus sulfur chlorine solid electrolyte powder and the fiberized PTFE binder in Example 2 for use.

[0080] 2. Set up 1 nozzle to prepare 4 layers of solid-state battery cell blocks: first, use the selective laser sintering process to print the bipolar current collector. After the current collector is printed and completely cured for 15 minutes, use the binder injection molding process to print NCM811 ternary positive electrode powder on the current collector. After the positive electrode is printed and completely cured for 30 minutes, use the binder injection molding process to print the fiberized binder layer on the positive electrode layer. After the printing is completed and completely cured for 5 minutes, use the selective laser sintering process to print the solid electrolyte powder on the positive electrode layer. After the solid electrolyte is printed and completely cured for 15 minutes, use the binder injection molding process to print lithium indium alloy powder on the solid electrolyte layer. Repeat the above preparation unit to obtain a solid-state battery cell block; 3. The obtained solid-state battery cell block is subjected to isostatic pressing at a pressure of 500 MPa, a temperature of 25 degrees Celsius, and a time of 15 minutes; 4. Cut the block to obtain a solid-state battery cell with a size of 6 cm × 8 cm; 5. Weld the pole ears on both sides of the solid-state battery cell and encapsulate it with an aluminum-plastic film to obtain a finished battery cell.

[0081] Comparative Example 2

[0082] This comparative example provides a solid-state battery, and the preparation method thereof is different from that of Example 2 only in that the first bipolar current collector layer and the second bipolar current collector layer are not obtained by 3D printing, but are directly coated with ready-made stainless steel foil.

[0083] Test Example 1

[0084] The present invention tests the performance and output voltage of the solid-state batteries prepared in the embodiments and comparative examples, and the results are shown in Table 1.

[0085] Detection methods include: Output voltage: Use a universal digital meter to measure the positive and negative voltages of the battery cell; Rate performance: The battery cell is charged and discharged to test the capacity retention rate at a 3C discharge rate; Production efficiency: the time taken to produce a single battery cell (unit: min).

[0086] Table 1

[0087] It should be noted that according to the 3D printing method of the present invention, raw materials such as positive and negative electrodes, fiberized binders and solid electrolytes can be arbitrarily replaced with other raw materials specified in the present invention, which is equivalent to the effect of the embodiment.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for 3D printing a solid-state battery, characterized in that: include: The entire solid-state battery cell is printed in an integrated manner using 3D printing to obtain a solid-state battery cell block; the solid-state battery cell block is then laminated; wherein the solid-state battery cell block includes, from bottom to top, a first bipolar current collector layer, a first fibrous binder layer, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, a second fibrous binder layer, and a second bipolar current collector layer.

2. The method for 3D printing a solid-state battery according to claim 1, characterized in that: The raw material of the first fiberized binder layer and the raw material of the second fiberized binder layer are independently and differently fiberized binders, and the binder includes one or more of polytetrafluoroethylene, polyvinyl pyrrolidone and polyvinylidene fluoride; the fiberization includes: high-speed shearing in a high mixer or air flow crushing in an air pulverizer.

3. The method for 3D printing a solid-state battery according to claim 1, characterized in that: When 3D printing a solid-state battery, each 3D printing nozzle corresponds to a raw material, and multiple layers are printed simultaneously; preferably, when 3D printing a solid-state battery, each 3D printing nozzle corresponds to a raw material, and multiple layers are printed simultaneously; preferably, when 3D printing is performed, from bottom to top, first print the first bipolar current collector layer, and then print the positive electrode layer on the first bipolar current collector layer 0.5 to 2 minutes later; then print the first fiberized binder layer on the positive electrode layer 0.5 to 2 minutes later; then print the solid electrolyte layer on the first fiberized binder layer 0.5 to 2 minutes later; then print the negative electrode layer on the solid electrolyte layer 0.5 to 2 minutes later; then print the second fiberized binder layer on the negative electrode layer 0.5 to 2 minutes later; then print the second bipolar current collector layer on the second fiberized binder layer 0.5 to 2 minutes later, to achieve simultaneous printing of multiple layers, and after printing, it is a battery unit.

4. The method for 3D printing a solid-state battery according to any one of claims 1 to 3, characterized in that: The lamination comprises a rolling or isostatic pressing process, and the lamination pressure is greater than 200 MPa.

5. The method for 3D printing a solid-state battery according to any one of claims 1 to 3, characterized in that: During the 3D printing process, a single layer rolling is performed while printing each layer; preferably, the pressure of the single layer rolling is 5-15 MPa.

6. The method for 3D printing a solid-state battery according to any one of claims 1 to 3, characterized in that: The 3D printing process includes one or more of a binder jet printing process, a fused deposition printing process, and a selective laser sintering printing process; Preferably, the positive electrode layer, the negative electrode layer, the first fiberized binder layer and the second fiberized binder layer are formed by the binder jet printing process.

7. The method for 3D printing a solid-state battery according to claim 2, characterized in that: The raw material of the first bipolar current collector layer and the raw material of the second bipolar current collector layer independently, identically or differently comprise stainless steel foil and / or aluminum-copper composite foil; And / or, the raw materials of the positive electrode layer include positive electrode active material and conductive agent; preferably, the positive electrode active material includes lithium iron phosphate, lithium cobalt oxide, lithium nickel manganese oxide, ternary nickel cobalt manganese oxide or lithium-rich manganese base; the conductive agent includes one or more of super-p, conductive carbon black, acetylene black, graphene and carbon nanotubes; And / or, the raw material of the solid electrolyte layer includes one or more of an oxide solid electrolyte, a sulfide solid electrolyte and a halide solid electrolyte; preferably, the oxide solid electrolyte includes one or more of lithium lanthanum zirconium oxide with a garnet structure, lithium lanthanum zirconium tantalum oxide with a garnet structure, lithium aluminum titanium phosphate with a NASICON structure and lithium aluminum germanium phosphate with a NASICON structure; the sulfide solid electrolyte includes one or more of lithium phosphorus sulfur chlorine, lithium germanium phosphorus sulfur, lithium tin phosphorus sulfur, lithium phosphorus sulfur and lithium tin sulfur; the halide solid electrolyte includes one or more of lithium indium chloride, lithium holmium chloride, lithium yttrium chloride, lithium scandium chloride and lithium erbium chloride; And / or, the raw material of the negative electrode includes one or more of graphite, silicon carbon, metallic lithium and lithium alloy.

8. The method for 3D printing a solid-state battery according to claim 7, characterized in that: When the raw material of the solid electrolyte layer is an oxide solid electrolyte, sintering is further performed after lamination, and the sintering temperature is 200-1000 degrees Celsius; and other solid electrolytes except the oxide solid electrolyte are not sintered after lamination.

9. The method for 3D printing a solid-state battery according to claim 8, characterized in that: include: S1: preparing raw material powder of the first bipolar current collector layer, raw material powder of the first fiberized binder layer, raw material powder of the positive electrode layer, raw material powder of the solid electrolyte layer, raw material powder of the negative electrode layer, raw material powder of the second fiberized binder layer, and raw material powder of the second bipolar current collector layer; using 3D printing to print the entire solid-state battery cell in an integrated manner, during the 3D printing process, single-layer rolling is performed while printing each layer, and a solid-state battery cell block is obtained after printing; S2: laminating the solid-state battery cell blocks; S3: Cut the laminated solid battery cell blocks according to the battery cell size requirements; S4: Encapsulating the cut battery cells to obtain solid-state battery cells connected in series; When the raw material of the solid electrolyte layer is an oxide solid electrolyte, the cutting in S3 further includes sintering, and the sintering temperature is 200-1100 degrees Celsius.

10. A solid-state battery, characterized in that: It is prepared by the method for 3D printing solid-state batteries according to any one of claims 1 to 9.

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