3D printing suspension for overhanging elements, electrode sheet, battery cell, and solid-state battery
Patent Information
- Application Number
- RU2025130775
- Authority / Receiving Office
- RU · RU
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2025-06-20
- Filing Date
- 2025-09-22
- Publication Date
- 2026-09-29
- Estimated Expiration
- 2045-09-22
Smart Images
Figure 00000001_ABST
Abstract
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present invention claims foreign priority of Chinese Patent Application No. 202510833229.1, filed on June 20, 2025, and entitled "3D PRINTING OVERHANG SLURRY, ELECTRODE SHEET, BATTERY CELL, PREPARATION METHODS THEREOF, AND SOLID-STATE BATTERY", the contents of which are incorporated herein by reference in their entirety. TECHNICAL FIELD
[0002] The present invention relates to the technical field of solid-state batteries, such as a slurry for 3D printing overhanging elements, an electrode sheet, a battery element, and a solid-state battery.BACKGROUND OF THE INVENTION
[0003] The negative electrode overhang section is the portion of the negative electrode sheet that extends beyond the positive electrode sheet in the length and / or width directions. This design is intended to prevent problems and improve battery safety. The problem is that during charging, lithium ions deposit on the surface of the negative electrode, forming lithium dendrites that can puncture the separator, cause an internal short circuit in the battery, and lead to thermal runaway. However, a fully solid-state battery requires relatively high pressure during the assembly process.In this field of technology, a larger negative electrode sheet and a smaller positive electrode sheet are used in the sealing and assembly of a solid-state battery, but due to the uneven size and force distribution on the electrode sheets, such a design can easily cause the overhanging portion of the negative electrode to break, resulting in contact between the positive and negative electrodes and leading to a short circuit of the battery.
[0004] To solve the problem that the negative electrode overhang portion may collapse during the assembly process of a solid-state battery, causing contact between the positive and negative electrodes and leading to a short circuit in the battery, a common solution is to place / load a support material in the overhang gap corresponding to the negative electrode overhang portion to reduce the collapse of the negative electrode overhang portion during the assembly process of the solid-state battery. Currently, the method for placing / loading a material in the overhang gap includes a coating method and a casting method. However, these placement / loading methods cannot effectively control the amount of the placed / loaded material during the placement / loading process, resulting in a failure to achieve the desired effect of filling the overhang gap.
[0005] It should be noted that the information disclosed above in the "Background of the Invention" section is used only to enhance the understanding of the background of the present invention and, thus, may include information that is not related to the prior art known to those skilled in the art. SUMMARY OF THE INVENTION
[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary of the invention is provided below. This summary is not an exhaustive overview and is not intended to identify key / critical elements or describe the scope of these embodiments, but rather serves as a preface to the detailed description that follows.
[0007] In some embodiments, the present invention provides a 3D printing slurry for overhanging elements, an electrode sheet, a battery cell, and a solid-state battery. The 3D printing slurry for overhanging elements may be suitable for a 3D printing method. The 3D printing method can precisely control printing parameters, such as the discharge rate, thereby achieving the desired gap-filling effect for the overhanging element.
[0008] In a first aspect, the present invention provides a slurry for 3D printing overhanging features, characterized in that it contains: composite powders, a binder, a surfactant and a solvent; wherein the mass ratio of the composite powders and the binder is 4-20:1, the mass ratio of the surfactant and the binder is 0.0005-0.02:1, and the solids percentage of the slurry for 3D printing overhanging features is 60%-75%;the composite powders contain inorganic particles of a solid electrolyte and two-dimensional layered powders, the mass ratio of the inorganic particles of the solid electrolyte and the two-dimensional layered powders is 0.5-1.5:1, the range of particle size distribution of each of the inorganic particles of the solid electrolyte is 0.01-2 μm, the mass fraction of the first inorganic particles of the solid electrolyte with a particle size of each of the first inorganic particles of the solid electrolyte in the range of 0.01-0.3 μm is 25%-50%, the two-dimensional size of each of the two-dimensional layered powders is 0.6-2 μm, and some of the inorganic particles of the solid electrolyte are embedded in the intermediate layer and / or the surface of the sheet layer of the two-dimensional layered powders.
[0009] In a preferred embodiment, in the inorganic solid electrolyte particles, the mass fraction of the second inorganic solid electrolyte particles with a particle size of each of the second inorganic solid electrolyte particles in the range of 0.3-0.6 μm is 40%-75%; and / or in the inorganic solid electrolyte particles, the mass fraction of the third inorganic solid electrolyte particles with a particle size of each of the third inorganic solid electrolyte particles in the range of 0.6-2 μm is 0%-20%;when the mass fraction of the third inorganic solid electrolyte particles is not equal to 0, the inorganic solid electrolyte particles contain the first inorganic solid electrolyte particles, the second inorganic solid electrolyte particles and the third inorganic solid electrolyte particles, and the sum of the mass fraction of the first inorganic solid electrolyte particles, the mass fraction of the second inorganic solid electrolyte particles and the mass fraction of the third inorganic solid electrolyte particles is 100%.;
[0010] In a preferred embodiment, the particle size ratio of each of the second inorganic solid electrolyte particles in the range of 0.3-0.6 μm and each of the first inorganic solid electrolyte particles is 1:0.03-0.4; and / or the particle size ratio of each of the third inorganic solid electrolyte particles in the range of 0.6-2 μm and each of the second inorganic solid electrolyte particles in the range of 0.3-0.6 μm is 1:0.25-0.6; and / or the mass ratio of the second inorganic solid electrolyte particles with the particle size of each of the second inorganic solid electrolyte particles in the range of 0.3-0.6 μm and the first inorganic solid electrolyte particles is 4-7:3-6;and / or the mass ratio of the third inorganic particles of the solid electrolyte with a particle size of each of the third inorganic particles of the solid electrolyte in the range of 0.6-2 μm, the second inorganic particles of the solid electrolyte with a particle size of each of the second inorganic particles of the solid electrolyte in the range of 0.3-0.6 μm and the first inorganic particles of the solid electrolyte is 0-2:4-7:3-6; and the third inorganic particles of the solid electrolyte are not equal to 0.
[0011] In a preferred embodiment, the inorganic solid electrolyte particles include one or more of an oxide-based solid electrolyte particle, a halide-based solid electrolyte particle, a sulfide-based solid electrolyte particle, a hydride-based solid electrolyte particle, and a nitride-based solid electrolyte particle; and / or the two-dimensional layered powders include two-dimensional layered heat-conducting powders; and / or the two-dimensional layered powders contain one or more of a two-dimensional layered nitride inorganic material, a layered silicate material, a layered sulfide, and a two-dimensional metal-organic framework; and / or two-dimensional layered powders include one or more of hexagonal boron nitride, two-dimensional layered aluminum nitride, two-dimensional layered carbon nitride, montmorillonite, MXene, molybdenum disulfide, tungsten disulfide, and a two-dimensional metal-organic framework;and / or the binder comprises one or more of polyvinylidene fluoride, nitrile rubber, butadiene rubber, styrene-butadiene rubber, poly(propylene carbonate), poly(tert-butyl acrylate), poly(ethylene glycol) diacrylate, poly(ethylene oxide), poly(ethylene methyl acrylate), poly(methyl methacrylate), poly(ethylene glycol) diacrylate, polyacrylonitrile, polyisobutylene, poly(ethylene vinyl acetate) and derivatives thereof; and / or the solvent comprises one or more of N,N-dimethylacetamide, N-methylpyrrolidone, acetonitrile, toluene, xylene, butyl butyrate, isobutyl butyrate, ethyl acetate, chloroform, tetrahydrofuran and alkanes; and / or the surfactant comprises one or more of a linear alkyl primary thiol, polyethylene glycol octylphenyl ether, polysorbate 20, sorbitan monooleate, oleic acid, stearic acid, and a hydroxy-functionalized alkyl ammonium salt.
[0012] In a preferred embodiment, the suspension further comprises a lithium salt; wherein the weight ratio of the lithium salt to the binder is 0.05-0.15:1.
[0013] In a preferred embodiment, the weight ratio of the lithium salt to the binder is 0.08-0.12:1 or 0.1:1; and / or the lithium salt includes one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate and lithium trifluoromethanesulfonate.
[0014] In a preferred embodiment, the weight ratio of the composite powders to the binder is 4-18:1, 5-15:1, 8-12:1, or 9-10:1; and / or the weight ratio of the surfactant to the binder is 0.001-0.02:1, 0.005-0.02:1, or 0.01-0.02:1.
[0015] In the second aspect of the present invention, there is provided an electrode sheet, characterized in that it comprises: a positive electrode sheet or a negative electrode sheet; wherein when the electrode sheet comprises a positive electrode sheet, the positive electrode sheet comprises an uncoated foil portion, and a 3D printing slurry for overhanging features is located on the uncoated foil portion; when the electrode sheet comprises a negative electrode sheet, the negative electrode sheet comprises an overhang portion, and a 3D printing slurry for overhanging features is located on the overhang portion of the negative electrode sheet;when the electrode sheet comprises a negative electrode sheet, which is a negative electrode composite sheet, which contains a solid electrolyte layer located on each of the two side surfaces of the negative electrode sheet, the 3D printing slurry for overhanging elements is located on the surface of the solid electrolyte layer of the negative electrode composite sheet, corresponding to the overhang portion of the negative electrode sheet; and wherein the 3D printing slurry for overhanging elements is the above-mentioned 3D printing slurry for overhanging elements.
[0016] In a third aspect of the present invention, there is provided a battery element, characterized in that it comprises: alternately laid positive electrode sheets and negative electrode sheets; wherein one of the solid electrolyte layers is located between each adjacent of the positive electrode sheets and one of the negative electrode sheets; each of the negative electrode sheets extends beyond each of the positive electrode sheets on at least one side in the circumferential direction to form an overhang portion; the encapsulation structure is located in a gap portion for the overhanging element corresponding to the overhang portion; the encapsulation structure is obtained by placing a slurry for 3D printing of overhanging elements in the gap portion for the overhanging element, and the slurry for 3D printing of overhanging elements is the above-mentioned slurry for 3D printing of overhanging elements.
[0017] In a preferred embodiment, the positive electrode sheet comprises a foil section without coating, and the slurry for 3D printing of overhanging elements is located on the foil section without coating; or the negative electrode sheet comprises an overhanging section, and the slurry for 3D printing of overhanging elements is located on the overhanging section of the negative electrode sheet; or the negative electrode sheet is a negative electrode composite sheet comprising a solid electrolyte layer located on each of the two side surfaces of the negative electrode sheet, the slurry for 3D printing of overhanging elements is located on the surface of the solid electrolyte layer of the negative electrode composite sheet corresponding to the overhanging section of the negative electrode sheet.
[0018] In a fourth aspect of the present invention, a solid-state battery is provided, characterized in that it comprises the above-mentioned electrode sheet; or the above-mentioned battery element.
[0019] The 3D printing suspension of overhanging elements, electrode sheet, battery element and solid-state battery provided in the aspects of the present invention can achieve the following technical effects.
[0020] The 3D printing slurry for overhanging features in some embodiments of the present invention provides a balance between a high solids content and rheological properties, making the 3D printing slurry for overhanging features suitable for the 3D printing method by providing printability and high strength of the slurry with a high solids content, i.e., ensuring both the print strength and the print smoothness, which makes it possible to obtain an encapsulation structure with the desired effect in the gap for the overhanging feature. In addition, the combination of inorganic solid electrolyte particles with a wide range of particle size distribution and two-dimensional layered powders allows the inorganic solid electrolyte particles, which correspond to defects in the gap between the layers and the surface of the sheet layer of the two-dimensional layered powders, to be embedded in the intermediate layer and / or the surface of the sheet layer of the two-dimensional layered powders.Thus, the defects in the sheet layer surface of the two-dimensional layered powders provide affinity sites for lithium ions and interact with the embedded inorganic solid electrolyte particles to create a continuous transport path for lithium ions, thereby reducing the risk of short circuit and capacity loss caused by lithium deposition on the edge of the negative electrode side, achieving the desired gap filling effect for the overhanging element.
[0021] In some embodiments of the present invention, inorganic solid electrolyte particles and two-dimensional layered powders are uniformly mixed by ball milling to form composite powders, and the composite powders are then uniformly mixed with other raw materials. During the ball milling process, strong collisions and friction between the inorganic solid electrolyte particles and the two-dimensional thermally conductive material further create multiple defects on the surface of the two-dimensional layered material, providing a large number of affinity sites for lithium ions.In addition, under the action of the shear force during milling, the amount of inorganic solid electrolyte particles embedded in the intermediate layer and / or the surface of the sheet layer of the two-dimensional layered powders can be increased, thereby jointly creating a better continuous transport path for lithium ions, reducing the risk of short circuit and capacity loss caused by lithium deposition on the edge of the negative electrode side.
[0022] In some embodiments of the present invention, the encapsulation structure of the overhanging element can be placed on the electrode sheet using a 3D printing method, wherein the 3D printing method allows for precise control of the printing volume, which ensures good control of parameters such as the thickness and uniformity of the encapsulation structure, and also ensures high printing speed and high efficiency.
[0023] The foregoing general description and the following description are illustrative and explanatory only and are not intended to limit the present invention.BRIEF DESCRIPTION OF THE DRAWINGS
[0024] One or more embodiments are shown by way of example with the accompanying drawings. These exemplary illustrations and drawings do not limit the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not limit the relationship.
[0025] Fig. 1 shows a structural schematic view of some composite powders in suspension for 3D printing overhanging features according to some embodiments of the present invention.
[0026] Fig. 2 shows a flow chart of a method for producing a slurry for 3D printing overhanging elements according to some embodiments of the present invention.
[0027] Fig. 3 shows a block diagram of a method for manufacturing a battery cell according to some embodiments of the present invention.
[0028] Fig. 4 shows a graph of the rheological property curves of suspensions for 3D printing of overhanging elements according to some embodiments of the present invention.
[0029] Reference positions: 11 - two-dimensional layered powder; 12 - inorganic solid electrolyte particle.DETAILED DESCRIPTION
[0030] For a more detailed understanding of the features and technical solution of embodiments of the present invention, the implementation of some embodiments of the present invention is described in detail below with reference to the drawings. The drawings are for reference and illustration only and are not intended to limit the embodiments of the present invention. In the following technical description, for the convenience of explanation, numerous details are provided to ensure a thorough understanding of the disclosed embodiments. However, one or more embodiments can be practiced without these details. In other cases, well-known structures and devices are shown in a simplified form to simplify the drawings.
[0031] The terms "first," "second," etc., in the description of the embodiments, the claims, and the above drawings are used to distinguish similar objects and are not used to describe a specific sequence or chronological order. It should be understood that the terms used are interchangeable in appropriate circumstances for understanding the embodiments of the present invention described herein. Furthermore, the terms "comprise" and "have," and any variations thereof, are intended to encompass non-exclusive inclusion.
[0032] In the embodiments of the present invention, the terms "upper," "lower," "inner," "middle," "outer," "front," "rear," etc., indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the present invention and embodiments and are not intended to limit the said devices, elements, or components to a specific orientation or their design and operation in a specific orientation. Moreover, the above terms can be used to express meanings other than indicating an orientation or positional relationship. For example, the term "upper" in some cases can also be used to indicate a specific fastening or coupling relationship. Those skilled in the art can understand the specific meanings of these terms in the embodiments of the present invention according to specific situations.
[0033] Furthermore, the terms "located," "connect," and "fix" should be understood in a broad sense. For example, "connect" may involve a fixed connection, a detachable connection, or an integral structure; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium; or an internal connection between two devices, elements, or components. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present invention according to specific situations.
[0034] Unless otherwise specified, the term "several" means two or more.
[0035] In embodiments of the present invention, the symbol " / " indicates an "or" relationship between the preceding and following objects. For example, A / B means: A or B.
[0036] The term "and / or" describes the associative relationship between related objects, indicating the possibility of three types of relationship. For example, A and / or B can refer to either A alone, B alone, or both A and B.
[0037] It should be noted that, unless there is a contradiction, the embodiments and features in the present invention can be combined with each other.
[0038] As shown in Fig. 1, in some embodiments of the present invention, a slurry for 3D printing overhanging features is provided, which may contain composite powders, a binder, a surfactant, and a solvent. The weight ratio of the composite powders and the binder is 4-20:1, the weight ratio of the surfactant and the binder is 0.0005-0.02:1, and the solids percentage of the slurry for the overhanging features is 60%-75%. The composite powders may contain inorganic solid electrolyte particles and two-dimensional layered powders. The weight ratio of the inorganic solid electrolyte particles and the two-dimensional layered powders is 0.5-1.5:1.The particle size distribution range of each of the inorganic solid electrolyte particles is 0.01-2 μm, and the mass fraction of the first inorganic solid electrolyte particles with a particle size of each of the first inorganic solid electrolyte particles in the range of 0.01-0.3 μm is 25%-50%. The two-dimensional size of each of the two-dimensional layered powders is 0.6-2 μm. Some of the inorganic solid electrolyte particles 12 are embedded in the intermediate layer and / or the surface of the sheet layer of the two-dimensional layered powders 11.
[0039] The 3D printing slurry for overhanging features in some embodiments of the present invention provides a balance between a high solids content and rheological properties, which makes the 3D printing slurry for overhanging features suitable for the 3D printing method, ensuring printability and high strength of the slurry with a high solids content, i.e., ensuring both the print strength and the print smoothness, which makes it possible to obtain an encapsulation structure with the desired effect in the gap for the overhanging feature. In addition, the combination of inorganic solid electrolyte particles with a wide range of particle size distribution and two-dimensional layered powders allows the inorganic solid electrolyte particles, which correspond to defects in the gap between the layers and the surface of the sheet layer of the two-dimensional layered powders, to be embedded in the intermediate layer and / or the surface of the sheet layer of the two-dimensional layered powders.Thus, the defects in the sheet layer surface of the two-dimensional layered powders provide affinity sites for lithium ions and interact with the embedded inorganic solid electrolyte particles to create a continuous transport path for lithium ions, thereby reducing the risk of short circuit and capacity loss caused by lithium deposition on the edge of the negative electrode side, achieving the desired gap filling effect for the overhanging element.
[0040] The solids content of the 3D printing slurry for overhanging features in some embodiments of the present invention is 60% to 75%, which is very high. By combining inorganic solid electrolyte particles of varying sizes and a two-dimensional material, as well as adjusting the surfactant, the rheological properties of the slurry are significantly improved, achieving a balance between the rheological properties and the high solids content of the 3D printing slurry for overhanging features with such a solids content.Thus, the 3D printing slurry for overhanging features has the appropriate amount of solids and the appropriate distance between the particles and, thus, has the appropriate rheological properties, which makes the 3D printing slurry for overhanging features suitable for the 3D printing method, ensuring the manufacturability and stability of 3D printing, as well as ensuring the strength and density of the encapsulation structure of the printed overhanging feature. It should be understood that the percentage of solids of the 3D printing slurry for overhanging features can be, without limitation, the percentage of solids by weight or the percentage of solids by volume. In some embodiments, the percentage of solids of the 3D printing slurry for overhanging features is the percentage of solids by weight. The percentage of solids can be adjusted by the amount of solvent added, i.e.The amount of solvent in the 3D printing slurry for overhanging elements in some embodiments of the present invention is determined based on the percentage of solids in the slurry. The type of solvent is not limited.
[0041] In some embodiments, the solvent may include one or more of N,N-dimethylacetamide, N-methylpyrrolidone, acetonitrile, toluene, xylene, butyl butyrate, isobutyl butyrate, ethyl acetate, chloroform, tetrahydrofuran, and alkanes.
[0042] In some embodiments, the percentage solids content of the 3D printing slurry for overhanging features is 60%-70%. In some embodiments, the percentage solids content of the 3D printing slurry for overhanging features is 60%-65%.
[0043] In some embodiments, the solids percentage of the 3D printing slurry for overhanging elements is 60%, 62%, 65%, 70%, or 75%, or any value in the range of 60%-75%.
[0044] The viscosity of the slurry for 3D printing overhanging elements in some embodiments of the present invention is 2-10 Pa s -1 Low viscosity, good rheological properties.
[0045] In a suspension for 3D printing of overhanging elements in some embodiments of the present invention, by controlling the mass fraction of the first inorganic solid electrolyte particles with a particle size of each of the first inorganic solid electrolyte particles in the range of 0.01-0.3 μm, the used amount of the first inorganic solid electrolyte particles is guaranteed to be in the range of small particle sizes, so that at least some of the nano-sized first inorganic solid electrolyte particles can be embedded in the intermediate layer and / or surface of the sheet layer of two-dimensional layered powders, allowing the nano-sized inorganic small particles of the solid electrolyte to serve as "bridges" in the two-dimensional layered material.The anisotropy of the two-dimensional material and the random orientation of the nanoscale inorganic solid electrolyte particles complement each other, providing a quasi-isotropic three-dimensional network with ionic conductivity, effectively reducing ion transport resistance within the battery and improving battery safety and service life. Furthermore, small solid electrolyte particles can flow into the gaps between larger solid electrolyte particles, reducing interparticle flow resistance and further reducing suspension viscosity and improving rheological properties.In addition, the two-dimensional layered heat-conducting material can serve as a lubricant, in combination with a combination of different sizes of inorganic solid electrolyte particles, improve the rheological properties of the suspension, which helps to create a continuous ion transport path in the gap for the overhanging element and increase the density and strength of the encapsulation structure of the overhanging element.
[0046] In some embodiments, the mass fraction of the first inorganic solid electrolyte particles is 30%-50%. In some embodiments, the mass fraction of the first inorganic solid electrolyte particles is 30%-40%. In some embodiments, the mass fraction of the first inorganic solid electrolyte particles is 25%, 30%, 35%, 40%, 45%, 50%, or any value within 25%-50%. It should be understood that the mass fraction of the first inorganic solid electrolyte particles refers to the mass fraction of the first inorganic solid electrolyte particles relative to the total mass of all inorganic solid electrolyte particles.
[0047] In the inorganic solid electrolyte particles, excluding the first inorganic solid electrolyte particles, the particle size range of the remaining inorganic solid electrolyte particles is 0.3-2 μm. The inorganic solid electrolyte particles within this particle size range are not limited and can be determined based on the actual situation.
[0048] In some embodiments, in the inorganic solid electrolyte particles, the mass fraction of the second inorganic solid electrolyte particles with a particle size of each of the second inorganic solid electrolyte particles in the range of 0.3-0.6 μm is 40%-75%. In this embodiment, the ratio of the second inorganic solid electrolyte particles to the particle size of each of the second inorganic solid electrolyte particles is limited, which, in combination with the first inorganic solid electrolyte particles with a small particle size range, can further improve the rheological properties of the suspension, create a better continuous ion transport path, and further increase the density and strength of the encapsulation structure of the overhanging element.
[0049] In some embodiments, composite powders are obtained by uniformly mixing inorganic solid electrolyte particles and two-dimensional layered powders through milling. During milling, strong collisions and friction between the inorganic solid electrolyte particles and the two-dimensional thermally conductive material further create multiple defects on the surface of the two-dimensional layered material, providing a large number of affinity sites for lithium ions. Furthermore, under the action of shear force during milling, the number of inorganic solid electrolyte particles embedded in the intermediate layer and / or surface of the sheet layer of the two-dimensional layered powders can be increased, thereby jointly creating a better continuous transport path for lithium ions and reducing the risk of short circuits and capacity loss caused by lithium deposition on the edge of the negative electrode.
[0050] In some embodiments, composite powders are produced by uniformly mixing inorganic solid electrolyte particles and two-dimensional layered powders using ball milling. In some embodiments, the composite powders are produced using high-energy ball milling. The ball milling parameters are determined based on actual needs.
[0051] In some embodiments, the ball milling parameters may include: a ball to material ratio of 10-40:1; and / or a rotation speed of 400-600 rpm; and / or a ball milling duration of 1-2 hours. In some embodiments, the ball to material ratio is 20-40:1.
[0052] In some embodiments, the inorganic solid electrolyte particles may comprise first inorganic solid electrolyte particles and second inorganic solid electrolyte particles, that is, the particle size distribution range of the inorganic solid electrolyte particles may be 0.01-0.6 μm. In this embodiment, the inorganic solid electrolyte particles are composite particles with a two-level particle size, which are defined as two-level composite inorganic solid electrolyte particles. In this embodiment, the mass fraction of the first inorganic solid electrolyte particles is 25%-50%, and the mass fraction of the second inorganic solid electrolyte particles is 50%-75%.
[0053] In some embodiments, in the two-level composite inorganic solid electrolyte particles, the weight ratio of the second inorganic solid electrolyte particles to the first inorganic solid electrolyte particles is (4-7):(3-6). In some embodiments, the weight ratio of the second inorganic solid electrolyte particles to the first inorganic solid electrolyte particles is (5-6):(3-4).
[0054] In some embodiments, in the two-level composite inorganic solid electrolyte particles, the mass fraction of the first inorganic solid electrolyte particles is 30%-50%, and the mass fraction of the second inorganic solid electrolyte particles is 50%-70%.
[0055] In some embodiments, in the two-level composite inorganic solid electrolyte particles, the mass fraction of the first inorganic solid electrolyte particles is 30%-40%, and the mass fraction of the second inorganic solid electrolyte particles is 60%-70%.
[0056] In some embodiments, in the two-level composite inorganic solid electrolyte particles, the particle size ratio (defined as the first particle size ratio) of each of the second inorganic solid electrolyte particles and each of the first inorganic solid electrolyte particles is 1:0.03-0.4. That is, the particle sizes of the second and first inorganic solid electrolyte particles are determined within this range of particle size ratio. In some embodiments, the first particle size ratio is 1:0.03-0.3. In some embodiments, the first particle size ratio is 1:0.03-0.2. In some embodiments, the first particle size ratio is 1:0.03, 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25 or 1:0.3, etc.By limiting the first particle size ratio, the rheological properties of the suspension are further improved, a better continuous ion transport path is created, and the density and strength of the encapsulation structure of the overhanging element are further increased.
[0057] In some embodiments, the inorganic solid electrolyte particles may comprise third inorganic solid electrolyte particles with a particle size of each of the third inorganic solid electrolyte particles in the range of 0.6-2 μm, and the mass fraction of the third inorganic solid electrolyte particles is 0-20% and is not equal to 0. In this embodiment, in the inorganic solid electrolyte particles, the mass fraction of the second inorganic solid electrolyte particles with a particle size of each of the second inorganic solid electrolyte particles in the range of 0.3-0.6 μm is not limited, provided that the sum of the mass fractions of the first, second and third inorganic solid electrolyte particles is 100%. The inorganic solid electrolyte particles in this embodiment are defined as three-level composite inorganic solid electrolyte particles.
[0058] In the three-level composite inorganic solid electrolyte particles in this embodiment, the mass fraction of the first inorganic solid electrolyte particles is 25%-50%, the mass fraction of the second inorganic solid electrolyte particles is 40%-75%, and the mass fraction of the third inorganic solid electrolyte particles is 0%-20% and is not equal to 0; and the sum of the three mass fractions is 100%.
[0059] In some embodiments, in the three-level composite inorganic solid electrolyte particles, the weight ratio of the third inorganic solid electrolyte particles, the second inorganic solid electrolyte particles and the first inorganic solid electrolyte particles is (0-2):(4-7):(3-6); and the third inorganic solid electrolyte particles are not equal to 0. In some embodiments, the weight ratio of the third inorganic solid electrolyte particles, the second inorganic solid electrolyte particles and the first inorganic solid electrolyte particles is (1-2):(5-6):(3-4).
[0060] In some embodiments, in the three-level composite inorganic solid electrolyte particles, the mass fraction of the first inorganic solid electrolyte particles is 25%-50%, the mass fraction of the second inorganic solid electrolyte particles is 40%-60%, and the mass fraction of the third inorganic solid electrolyte particles is 0%-20% and is not equal to 0.
[0061] In some embodiments, in the three-level composite inorganic solid electrolyte particles, the mass fraction of the first inorganic solid electrolyte particles is 25%-40%, the mass fraction of the second inorganic solid electrolyte particles is 40%-60%, and the mass fraction of the third inorganic solid electrolyte particles is 5%-20%.
[0062] In some embodiments, in the three-level composite inorganic solid electrolyte particles, the mass fraction of the first inorganic solid electrolyte particles is 30%-40%, the mass fraction of the second inorganic solid electrolyte particles is 45%-60%, and the mass fraction of the third inorganic solid electrolyte particles is 10%-20%.
[0063] In the three-level composite inorganic solid electrolyte particles, the particle size ratio (defined as the second particle size ratio) of each of the third inorganic solid electrolyte particles and each of the second inorganic solid electrolyte particles is 1:0.25-0.6, and the particle size ratio (the same as the aforementioned first particle size ratio) of each of the second inorganic solid electrolyte particles and each of the first inorganic solid electrolyte particles is 1:0.03-0.4.
[0064] In some embodiments, the second particle size ratio is 1:0.3-0.5. In some embodiments, the second particle size ratio is 1:0.35-0.45. In some embodiments, the second particle size ratio is 1:0.4. In some embodiments, the second particle size ratio is 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55 or 1:0.6, etc. By limiting the second particle size ratio and the first particle size ratio, the rheological properties of the suspension are further improved, a better continuous ion transport path is created, and the density and strength of the encapsulation structure of the overhanging element are further increased.
[0065] In the embodiments of the present invention, the type of inorganic solid electrolyte particles is not limited. In some embodiments, the inorganic solid electrolyte particles may include, but are not limited to, one or more of an oxide-based solid electrolyte particle, a halide-based solid electrolyte particle, a sulfide-based solid electrolyte particle, a hydride-based solid electrolyte particle, and a nitride-based solid electrolyte particle, which can be determined based on actual requirements.
[0066] In some embodiments of the present invention, two-dimensional layered powders may comprise two-dimensional powders with a certain thickness, and each of the two-dimensional powders may comprise multiple sheet layers. A certain gap exists between adjacent sheet layers. At least some of the first inorganic solid electrolyte particles with a particle size in the range of 0.01-0.3 μm may be embedded in the intermediate layer and / or the surface of the sheet layer of the two-dimensional layered powders. In addition, the two-dimensional layered powders may have surface defects on the two-dimensional surface of the sheet layer. These surface defects interact with the embedded inorganic solid electrolyte particles to create a continuous transport path for lithium ions, reducing the risk of short circuits and capacity loss caused by lithium deposition on the edge of the negative electrode side, achieving the desired effect of filling the gap for the overhanging element.
[0067] In some embodiments, the two-dimensional layered powders may include two-dimensional layered thermally conductive powders. The two-dimensional layered thermally conductive powders need only have certain thermal conductivity properties and are not limited. In this embodiment, the use of two-dimensional layered thermally conductive powders enables a quasi-isotropic three-dimensional network with an ionic conductivity function, formed by the two-dimensional layered thermally conductive powders and nanoscale inorganic solid electrolyte particles, to have a thermal conductivity function. Thus, a quasi-isotropic dual-functional three-dimensional network with ionic conductivity and thermal conductivity is created, effectively reducing heat concentration and ion transport resistance within the battery, improving battery safety and service life.
[0068] In some embodiments, the two-dimensional size of each of the two-dimensional layered powders is 0.8-2 μm. In some embodiments, the two-dimensional size of each of the two-dimensional layered powders is 1-1.5 μm.
[0069] In some embodiments, the thickness of each particle of the two-dimensional layered powder (or two-dimensional layered thermally conductive powder) is 0.7-20 nm. The thickness refers to the thickness of each particle of the two-dimensional layered powder in a direction perpendicular to the two-dimensional direction. Each particle of the two-dimensional layered powder may be a single-layer two-dimensional powder or a multi-layer two-dimensional powder.
[0070] In some embodiments, the two-dimensional layered powders may include multilayer two-dimensional powders (or multilayer two-dimensional thermally conductive powders), wherein the thickness of each powder particle of the multilayer two-dimensional powders is 2-20 nm. In some embodiments, the thickness of each powder particle of the multilayer two-dimensional powders is 5-20 nm. In some embodiments, the thickness of each powder particle of the multilayer two-dimensional powders is 10-20 nm.
[0071] In some embodiments, the mass ratio (defined as the first mass ratio) of the inorganic solid electrolyte particles and the two-dimensional layered powders is 0.5-1.5:1. For example, the first mass ratio is 0.5:1, 0.8:1, 1:1, 1.2:1, or 1.5:1.
[0072] In some embodiments, the two-dimensional layered powders may comprise one or more of a two-dimensional layered nitride inorganic material, a layered silicate material, a layered sulfide, and a two-dimensional metal-organic framework, which can be determined based on the actual situation.
[0073] In some embodiments, the two-dimensional layered inorganic nitride material may include hexagonal boron nitride, two-dimensional layered aluminum nitride, or two-dimensional layered carbon nitride.
[0074] In some embodiments, the layered silicate material may include montmorillonite.
[0075] In some embodiments, the layered sulfide may include molybdenum disulfide or tungsten disulfide.
[0076] In some embodiments, the two-dimensional layered powders may include one or more of hexagonal boron nitride, two-dimensional layered aluminum nitride, two-dimensional layered carbon nitride, montmorillonite, MXene, molybdenum disulfide, tungsten disulfide, and two-dimensional metal-organic frameworks.
[0077] In some embodiments of the present invention, a binder is used to bind composite powders in a 3D printing slurry for overhanging elements. By controlling the ratio of composite powders to binder, the slurry can have rheological properties suitable for the 3D printing method, and the stability, heat dissipation, and ion transport of the formed overhanging element encapsulation structure can be ensured. Thus, the weight ratio of composite powders to binder can be controlled at a level of (4-20):1.
[0078] In some embodiments, the weight ratio of the composite powders and binder is (4-18):1. In some embodiments, the weight ratio of the composite powders and binder is (5-15):1. In some embodiments, the weight ratio of the composite powders and binder is (8-12):1. In some embodiments, the weight ratio of the composite powders and binder is (9-10):1.
[0079] In some embodiments, the binder may include, but is not limited to, one or more of polyvinylidene fluoride, nitrile rubber, butadiene rubber, styrene-butadiene rubber, poly(propylene carbonate), poly(tert-butyl acrylate), poly(ethylene glycol) diacrylate, poly(ethylene oxide), poly(ethylene methyl acrylate), poly(methyl methacrylate), poly(ethylene glycol) diacrylate, polyacrylonitrile, polyisobutylene, poly(ethylene vinyl acetate), and derivatives thereof.
[0080] In a 3D printing slurry for overhanging elements in some embodiments of the present invention, a surfactant can reduce the interfacial tension between the slurry and the printing substrate (for example, not the uncoated foil portion of the positive electrode or the overhang portion of the negative electrode) and the side surface (or end surface) of the electrode, improve the wettability of the slurry, improve the adhesion strength between the overhang portion and the side surface (or end surface) of the electrode and the intermediate layer, and increase the stability of the encapsulation structure of the overhanging element.In addition, the surfactant can form a self-assembled lubricating layer on the surface of each inorganic solid electrolyte particle and each two-dimensional layered powder (or two-dimensional layered thermally conductive powder), reducing interparticle friction and improving the dispersion uniformity and rheological properties of the suspension. The surfactant ratio in the suspension must be controlled, for example, the weight ratio of surfactant to binder is (0.0005-0.02):1. The surfactant ratio in the suspension should not be too large, otherwise, the fluidity of the suspension may become excessive, making it difficult to maintain the shape accuracy of the printed structure. In addition, when the weight ratio of surfactant in the suspension is too large, bubbles are easily formed in the suspension, which adversely affects the printing density and strength after molding.
[0081] In some embodiments, the weight ratio of the surfactant to the binder is 0.001-0.02:1. In some embodiments, the weight ratio of the surfactant to the binder is 0.005-0.02:1. In some embodiments, the weight ratio of the surfactant to the binder is 0.01-0.02:1.
[0082] In some embodiments, the weight ratio of the surfactant to the binder is 0.005:1, 0.008:1, 0.01:1, 0.015:1, 0.02:1.
[0083] In some embodiments, the surfactant may include one or more of a linear alkyl primary thiol, polyethylene glycol octylphenyl ether, polysorbate 20, sorbitan monooleate, oleic acid, stearic acid, and a hydroxy-functionalized alkyl ammonium salt.
[0084] In some embodiments, the 3D printing slurry for overhanging elements may contain a lithium salt. The weight ratio of the lithium salt to the binder is 0.05-0.15:1. In this embodiment, by adding the lithium salt as an additional lithium source, a sufficient amount of lithium ions is provided in the encapsulation structure of the overhanging element, and the lithium salt interacts with the binder, inorganic solid electrolyte particles, and the two-dimensional layered material (or two-dimensional layered thermal conductive powders) to construct a continuous three-dimensional ion transport network. By controlling the amount of the lithium salt, an appropriate lithium ion concentration can be ensured, ensuring the lithium ion transport capacity without adversely affecting the ductility of the binder, and ensuring the strength and stability of the encapsulation structure of the overhanging element.
[0085] In some embodiments, the weight ratio of the lithium salt to the binder is 0.08-0.12:1. In some embodiments, the weight ratio of the lithium salt to the binder is 0.1:1.
[0086] In some embodiments, the lithium salt may include one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, and lithium trifluoromethanesulfonate.
[0087] As shown in Fig. 2, in some embodiments of the present invention, a method for producing a slurry for 3D printing overhanging elements is provided, and the method may include the following steps.
[0088] Operation S110 may include: preparing raw materials based on any of the suspensions for 3D printing of overhanging elements in the above-mentioned embodiments. In this operation S110, the raw materials may at least include inorganic solid electrolyte particles, two-dimensional layered powders, a binder, a surfactant, and a solvent. In some embodiments, the raw materials may include a lithium salt. The amounts of materials correspond to the amounts described with respect to any of the suspensions for 3D printing of overhanging elements in the above-mentioned embodiments.
[0089] Operation S120 may include: ball milling and mixing inorganic solid electrolyte particles and two-dimensional layered powders to produce composite powders.
[0090] Operation S130 may include: uniformly mixing the composite powders with other raw materials to form a slurry for 3D printing overhanging features. In this embodiment, the other raw materials may at least include a binder, a surfactant, and a solvent. In this embodiment, the other raw materials may include a lithium salt.
[0091] In some embodiments of the present invention, inorganic solid electrolyte particles and two-dimensional layered powders are uniformly mixed by ball milling to form composite powders, and the composite powders are then uniformly mixed with other raw materials. During the ball milling process, strong collisions and friction between the inorganic solid electrolyte particles and the two-dimensional thermally conductive material (or two-dimensional layered thermally conductive powders) further create multiple defects on the surface of the two-dimensional layered material, providing a large number of affinity sites for lithium ions.In addition, under the action of the shear force during milling, the amount of inorganic solid electrolyte particles embedded in the intermediate layer and / or the surface of the sheet layer of the two-dimensional layered powders can be increased, thereby jointly creating a better continuous transport path for lithium ions, reducing the risk of short circuit and capacity loss caused by lithium deposition on the edge of the negative electrode side.
[0092] In some embodiments, during operation S120, the ball milling parameter may include: a ball to material ratio of 10-40:1; and / or a rotation speed of 400-600 rpm; and / or a ball milling duration of 1-2 hours.
[0093] In some embodiments, the ratio of balls to material is 20-40:1.
[0094] During operation S130, uniformly mixing the composite powders with other raw materials may include: uniformly mixing the composite powders with other raw materials by stirring. In this embodiment, the stirring method is determined based on the actual situation.
[0095] In some embodiments of the present invention, an electrode sheet is provided. The electrode sheet may include a positive electrode sheet or a negative electrode sheet. When the electrode sheet includes a positive electrode sheet, the positive electrode sheet may comprise an uncoated foil portion, and a 3D printing slurry for overhanging elements is located on the uncoated foil portion. When the electrode sheet includes a negative electrode sheet, which is a negative electrode composite sheet containing a solid electrolyte layer located on each of the two side surfaces of the negative electrode sheet, the 3D printing slurry for overhanging elements is located on the surface of the solid electrolyte layer of the negative electrode composite sheet corresponding to the overhanging portion of the negative electrode sheet.The 3D printing suspension for overhanging elements is any of the 3D printing suspensions for overhanging elements described in the above embodiments, or a 3D printing suspension for overhanging elements prepared using any of the methods for producing a 3D printing suspension for overhanging elements in the above embodiments.
[0096] In some embodiments of the present invention, the 3D printing slurry for overhanging elements is located in a portion of the electrode sheet corresponding to the overhang portion, for example, the portion where the 3D printing slurry for overhanging elements is located is a portion of the uncoated foil of the positive electrode sheet, a surface of the overhang portion of the negative electrode sheet, or a surface of the solid electrolyte layer of the composite negative electrode sheet corresponding to the overhang portion, so that the 3D printing slurry for overhanging elements is located in a gap for an overhanging element related to a battery cell obtained by stacking, and the 3D printing slurry for overhanging elements is cured to obtain an overhanging element encapsulation structure.
[0097] In some embodiments of the present invention, the 3D printing slurry of overhanging elements may be located on the electrode sheet via a 3D printing method.
[0098] The 3D printing slurry for overhanging features located on the electrode sheet may, in some embodiments of the present invention, remain in a slurry state for subsequent processes. In some embodiments, the 3D printing slurry for overhanging features may be solidified before entering subsequent processes, which is not limited and can be determined based on the actual situation.
[0099] In some embodiments of the present invention, a battery cell is provided, and the battery cell may comprise alternately stacked positive electrode sheets and negative electrode sheets. Each layer of solid electrolyte is located between each adjacent positive electrode sheet and one negative electrode sheet. The negative electrode sheet extends beyond the positive electrode sheet on at least one side in the circumferential direction to form an overhang portion. An encapsulation structure is located in a gap portion for the overhanging element, corresponding to the overhang portion. The encapsulation structure is obtained by placing a slurry for 3D printing overhanging elements in the gap portion for the overhanging element.The 3D printing slurry for overhanging features may be any of the 3D printing slurries for overhanging features described in the above embodiments, or a 3D printing slurry for overhanging features produced by any of the methods for producing the 3D printing slurry for overhanging features in the above embodiments.
[00100] The battery cell in some embodiments of the present invention may comprise any of the 3D printing slurries for overhanging features in the above embodiments, and the battery cell has all the technical effects of the 3D printing slurry for overhanging features, which will not be repeated here.
[00101] In the battery cell in some embodiments of the present invention, the 3D printing slurry for overhanging features is cured to obtain an encapsulation structure. Curing is a process of evaporating a solvent in the slurry.Therefore, the curing temperature is determined depending on the type of solvent used. In some embodiments, the temperature is 60-150°C.
[00102] In some embodiments, the positive electrode sheet may be a positive electrode sheet of any of the electrode sheets in the above-mentioned embodiments. In some embodiments, the negative electrode sheet may be a negative electrode sheet or a composite negative electrode sheet in any of the electrode sheets in the above-mentioned embodiments.
[00103] As shown in Fig. 3, in some embodiments of the present invention, a method of manufacturing a battery cell is provided, and the method may include the following steps.
[00104] Operation S210 may include: preparing positive electrode sheets, negative electrode sheets, and solid electrolyte layers; a size of each of the negative electrode sheets is larger than a size of each of the positive electrode sheets on at least one side in a circumferential direction, so that each of the negative electrode sheets has an overhang portion; each of the positive electrode sheets is any of the positive electrode sheets in the above-mentioned embodiments; or each of the negative electrode sheets is any of the negative electrode sheets or the negative electrode composite sheets in the above-mentioned embodiments.
[00105] Operation S220 may include: alternately laying positive electrode sheets and negative electrode sheets, and placing one of the layers of solid electrolyte between each adjacent positive electrode sheet and one negative electrode sheet to obtain a battery element; the 3D printing slurry for overhanging elements after curing is placed in a gap portion for an overhanging element related to the battery element.
[00106] In some embodiments, during operation S210, preparing the positive electrode sheets may include: placing an active slurry for the positive electrode on the positive electrode current collector to form a layer of the positive electrode active material and leaving a portion of the foil without coating on the positive electrode current collector around the layer of the positive electrode active material; and printing the slurry for 3D printing overhanging elements onto the portion of the foil without coating of the positive electrode sheet by a 3D printing method to form the positive electrode sheet.
[00107] In some embodiments, during operation S210, preparing the negative electrode sheets may include: placing an active slurry for the negative electrode on a current collector of the negative electrode to obtain a layer of active material of the negative electrode; and printing the slurry for 3D printing overhanging features onto the surface of the overhang portion of the negative electrode sheet by a 3D printing method to obtain a negative electrode sheet.
[00108] In some embodiments, operation S210 may include: transfer printing a solid electrolyte layer onto both surfaces of the negative electrode sheet; and printing the slurry for 3D printing overhanging features onto the surface of the solid electrolyte layer corresponding to the overhang portion of the negative electrode sheet by a 3D printing method to obtain a composite negative electrode sheet.
[00109] In some embodiments, during operation S220, before alternately stacking the positive electrode sheets and the negative electrode sheets, the method may include: curing a slurry for 3D printing overhanging elements located on the positive electrode sheet or the negative electrode sheet to obtain a positive electrode sheet or a negative electrode sheet with an encapsulation structure. In some embodiments, during operation S220, after alternately stacking the positive electrode sheets and the negative electrode sheets, the method may include: curing a multilayer structure of the battery cell to obtain a battery cell with an encapsulation structure. Operation S220 is determined based on the actual situation.
[00110] In some embodiments of the present invention, a solid-state battery is provided, and the solid-state battery may comprise any of the electrode sheets in the above-mentioned embodiments; or any of the battery elements in the above-mentioned embodiments; or a battery element obtained by any of the methods for producing a battery element in the above-mentioned embodiments.
[00111] Some embodiments are given below to illustrate a 3D printing slurry of overhanging elements, an electrode sheet, a battery element, methods for producing the same, and a solid-state battery in order to more clearly explain the technical problems, technical solutions, and advantageous effects. It is obvious that the described embodiments are only some embodiments of the present invention, and not all embodiments.The following description of at least one illustrative embodiment is for illustrative purposes only and does not in any way limit the present invention or the scope of application of the present invention.
[00112] Technical solutions or conditions not specified in the embodiments are implemented in accordance with technical solutions or conditions described in the prior art literature or in accordance with the corresponding product specification. Reagents or devices without manufacturer indication are common products that can be obtained by commercial purchase.
[00113] Embodiment 1
[00114] A suspension for 3D printing of overhanging elements comprises composite powders, a binder, a lithium salt, a surfactant, and a solvent.The mass ratio of composite powders to binder is 4-20:1, the mass ratio of surfactant to binder is 0.0005-0.02:1, the mass ratio of lithium salt to binder is 0.05-0.15:1, and the solids content of the suspension for overhanging elements is 60%-75%. Composite powders contain inorganic solid electrolyte particles and two-dimensional layered powders. The mass ratio of inorganic solid electrolyte particles to two-dimensional layered powders is 0.5-1.5:1.The particle size distribution range of each of the inorganic particles of the solid electrolyte is 0.01-2 μm, the mass fraction of the first inorganic particles of the solid electrolyte with a particle size of each of the first inorganic particles of the solid electrolyte in the range of 0.01-0.3 μm is 25%-50%; the mass fraction of the second inorganic particles of the solid electrolyte with a particle size of each of the second inorganic particles of the solid electrolyte in the range of 0.3-0.6 μm is 40%-60%; the mass fraction of the third inorganic particles of the solid electrolyte with a particle size of each of the third inorganic particles of the solid electrolyte in the range of 0.6-2 μm is 0%-20% and is not equal to 0.The particle size ratio of each of the third inorganic solid electrolyte particles and each of the second inorganic solid electrolyte particles is 1:0.25-0.6; the particle size ratio of each of the second inorganic solid electrolyte particles and each of the first inorganic solid electrolyte particles is 1:0.03-0.4.
[00115] Each two-dimensional size of the two-dimensional layered powders is 0.6-2 μm. Some of the inorganic solid electrolyte particles are embedded in the intermediate layer and / or the surface of the sheet layer of the two-dimensional layered powders.
[00116] The 3D printing suspension of overhanging elements according to embodiment 1 is defined as having three-level composite inorganic solid electrolyte particles.
[00117] In embodiment 1, four suspensions are provided.The inorganic solid electrolyte particles are LATP oxide solid electrolyte, the binder is graft-modified polyvinylidene fluoride, the lithium salt is lithium bis(trifluoromethanesulfonyl)imide, the surfactant is polyethyleneglycol octylphenyl ether, and the solvent is low-boiling point tetrahydrofuran. The mass ratios of the composite powders, binder, lithium salt, surfactant, and solvent are successively 90:10:1:0.2:43, and the solids percentage of the suspension for overhanging elements is 60%-65%. The remaining raw material compositions are shown in Table 1. the first inorganic solid electrolyte particles second inorganic particles of solid electrolyte third inorganic particles of solid electrolyte two-dimensional layered powders first mass ratio suspension I 0.01 µm; 30% 0.3 µm; 60% 0.8 µm; 10% hexagonal boron nitride; 1.3 µm; 1,5:1 suspension II 0.01 µm; 30% 0.3 µm; 60% 0.8 µm; 10% montmorillonite; 1.3 µm; 1,5:1 suspension III 0.01 µm; 30% 0.3 µm; 60% 0.8 µm; 10% hexagonal boron nitride; 1.3 µm; 0,7:1 IV suspension 0.1 µm; 36% 0.5 µm; 46% 1.2 µm; 18% hexagonal boron nitride; 1.3 µm; 1,5:1
[00118] A method for producing a slurry for 3D printing overhanging features in embodiment 1 includes the following operations: preparing raw materials based on the slurry for 3D printing overhanging features in embodiment 1; the raw materials include inorganic particles of a solid electrolyte, two-dimensional layered powders, a binder, a lithium salt, a surfactant, and a solvent; mixing and high-energy ball milling the inorganic particles of a solid electrolyte and the two-dimensional layered powders to obtain composite powders; the high-energy ball milling parameters include: a ball-to-material ratio of 40:1; a rotation speed of 500 rpm; a ball milling duration of 1.5 hours; mixing the composite powders, a binder, a lithium salt, a surfactant, and a solvent to obtain a slurry for 3D printing overhanging features.
[00119] In embodiment 1, a test is performed to determine the rheological properties with respect to the suspension for 3D printing of overhanging elements. As shown in the graph of the rheological property curves of the suspensions for 3D printing of overhanging elements in Fig. 4, the viscosity of the suspension for 3D printing of overhanging elements in embodiment 1 (suspension I and suspension II) is 2-10 Pa s. -1. The viscosity is low, the rheological properties are good.
[00120] Embodiment 2
[00121] A suspension for 3D printing overhanging features contains composite powders, a binder, a lithium salt, a surfactant and a solvent. The mass ratio of the composite powders and the binder is 4-20:1, the mass ratio of the surfactant and the binder is 0.0005-0.02:1, the mass ratio of the lithium salt and the binder is 0.05-0.15:1, and the solids percentage of the suspension for the overhanging features is 60%-75%. The composite powders contain inorganic particles of a solid electrolyte and two-dimensional layered powders. The mass ratio of the inorganic particles of a solid electrolyte and two-dimensional layered powders is 0.5-1.5:1.The particle size distribution range of each of the inorganic solid electrolyte particles is 0.01-0.6 μm, the mass fraction of the first inorganic solid electrolyte particles with a particle size of each of the first inorganic solid electrolyte particles in the range of 0.01-0.3 μm is 25%-50%; the mass fraction of the second inorganic solid electrolyte particles with a particle size of each of the second inorganic solid electrolyte particles in the range of 0.3-0.6 μm is 50%-75%. The ratio of the particle sizes of each of the second inorganic solid electrolyte particles and each of the first inorganic solid electrolyte particles is 1:0.03-0.4. The two-dimensional size of each of the two-dimensional layered powders is 0.6-2 μm. Some of the inorganic solid electrolyte particles are embedded in the intermediate layer and / or the surface of the sheet layer of the two-dimensional layered powders.
[00122] The 3D printing suspension of overhanging elements in embodiment 2 is defined as having two-layer composite inorganic solid electrolyte particles.
[00123] In embodiment 2, suspension V is provided. Suspension V differs from suspension I in that the inorganic solid electrolyte particles only include first inorganic solid electrolyte particles with a mass fraction of 40% and second inorganic solid electrolyte particles with a mass fraction of 60%, the particle size of each of the first inorganic solid electrolyte particles is 0.01 μm, and the particle size of each of the second inorganic solid electrolyte particles is 0.3 μm. Other raw materials, quantities and manufacturing method are the same as those of suspension I.
[00124] Comparative Example 1
[00125] Comparative suspension I in Comparative Example 1 differs from suspension I in Embodiment 1 in that, in the manufacturing method, the inorganic solid electrolyte particles and the two-dimensional layered powders are mixed by mechanical stirring at a stirring speed of 500 rpm. Other raw materials, composition, and manufacturing method are the same as those of suspension I.
[00126] Comparative Example 2
[00127] Comparative suspension II in Comparative Example 1 differs from suspension I in Embodiment 1 in that the surfactant is excluded. Other raw materials, composition, and manufacturing method are the same as those of suspension I.
[00128] The rheological property curve of comparative suspension II in Comparative Example 2 is shown in Fig. 4.It can be seen that, compared with the suspension I according to Embodiment 1, the rheological properties of the comparative suspension II without a surfactant are significantly worse. This is because the surfactant can form a lubricating layer obtained by self-assembly on the surface of each of the inorganic solid electrolyte particles and each of the two-dimensional layered heat-conducting powders, reducing the friction between the particles and improving the rheological properties of the suspension.
[00129] Comparative Example 3
[00130] Comparative suspension III in Comparative Example 3 differs from suspension I in Embodiment 1 in that the raw materials do not include the two-dimensional layered powders, that is, the ratio of the two-dimensional layered powders in the composite powders is 0. Other raw materials, composition and manufacturing method are the same as those of suspension I.
[00131] The rheological property curve of comparative suspension III in comparative example 3 is shown in Fig. 4. It can be seen that the viscosity of comparative suspension III without the two-dimensional material is higher, but the processability is poor. This is because the suspension according to embodiment 1 combines the two-dimensional material and solid electrolyte particles with multiple particle sizes. Under the action of shear force, the two-dimensional material serves as a lubricant, effectively reducing the resistance to movement of solid powders in the suspension. Moreover, the solid electrolyte particles with multiple particle sizes allow the solid electrolyte particles with small particle sizes to flow into the gaps between the solid electrolyte particles with large particle sizes, reducing the flow resistance between the particles, which further reduces the viscosity of the suspension and improves the rheological properties.
[00132] Comparative Example 4
[00133] Comparative suspension IV in Comparative Example 4 differs from comparative suspension III in Comparative Example 3 in that the inorganic solid electrolyte particles include only one oxide solid electrolyte LATP with a particle size of 0.5 μm. Other raw materials, composition and manufacturing method are the same as those of comparative suspension III.
[00134] The rheological property curve of comparative suspension IV in Comparative Example 4 is shown in Fig. 4. It can be seen that the viscosity of comparative suspension IV, which does not contain either a two-dimensional material or a combination of multiple particle sizes, is higher and the processability is poorer. The reason is that the suspension in Embodiment 1 combines a two-dimensional material and solid electrolyte particles with multiple particle sizes. Under the action of a shear force, the two-dimensional material serves as a lubricant, effectively reducing the resistance to movement of solid powders in the suspension.Moreover, solid electrolyte particles with multiple particle sizes allow solid electrolyte particles with small particle sizes to flow into the gaps between solid electrolyte particles with large particle sizes, reducing the flow resistance between the particles, which further reduces the viscosity of the slurry and improves the rheological properties.
[00135] Embodiment 3
[00136] The positive electrode sheet may comprise an uncoated foil portion. An overhang member encapsulation structure is disposed on the uncoated foil portion. The overhang member encapsulation structure is obtained by printing an overhang member 3D printing slurry onto the uncoated foil portion using a 3D printing method and then curing the overhang member 3D printing slurry.
[00137] In embodiment 3, the suspensions IV in embodiment 1 and embodiment 2 are respectively used as a suspension for 3D printing of overhanging members, printed on the uncoated foil portion and cured, thereby respectively obtaining positive electrode sheets IV. In addition, the comparative suspensions I to IV in comparative examples 1 to 4 are respectively used as a suspension for 3D printing of overhanging members, printed on the uncoated foil portion and cured, thereby respectively obtaining comparative positive electrode sheets I to IV.
[00138] In embodiment 3, for subsequent assembly of a solid-state battery and testing for determining battery characteristics, a positive electrode sheet is prepared as follows.
[00139] The positive electrode sheet comprises a positive electrode current collector (e.g., an aluminum foil current collector) and a positive electrode active material layer disposed on the positive electrode current collector. Specifically, the positive electrode slurry was applied to the positive electrode current collector, placed in an air-blown oven and dried at 70°C for 2 hours, then transferred to a vacuum oven and dried at 60°C for at least 6 hours. The resulting dried electrode sheet was rolled, then cut to the appropriate size to obtain a positive electrode sheet in a semi-finished state with an uncoated foil portion left around the positive electrode active material layer, and then stored in a vacuum oven.A positive electrode suspension was obtained by uniformly dispersing a binder in the form of graft-modified polyvinylidene fluoride, Super P, a solid electrolyte LATP and an active material NCM811 in a weight ratio of 1:1:10:88 in a solvent in the form of N-methylpyrrolidone.
[00140] By means of a 3D printing method, the suspension for 3D printing overhanging elements is printed onto a portion of the uncoated foil of the positive electrode sheet in a semi-finished state with a printing width of 0.5 mm and a thickness corresponding to the thickness of the semi-finished positive electrode sheet. After drying and curing molding, a positive electrode sheet with an overhanging element encapsulation structure is obtained.
[00141] Embodiment 4
[00142] The battery cell comprises alternately laid positive electrode sheets and negative electrode sheets. A layer of solid electrolyte is located between each adjacent sheet of the positive electrode and one sheet of the negative electrode.The negative electrode sheet extends beyond the positive electrode sheet on at least one side in the circumferential direction to form an overhang portion. The encapsulation structure is located in a gap portion for the overhanging element corresponding to the overhang portion.
[00143] In embodiment 4, the positive electrode sheets IV in embodiment 3 are used as the positive electrode sheets, thereby respectively obtaining battery cells IV. In addition, comparative positive electrode sheets I-IV are used, thereby respectively obtaining comparative battery cells I-IV.
[00144] In embodiment 4, for subsequent assembly of the solid-state battery and testing for determining the battery characteristics, a lithium-indium alloy with a protective layer of silver and carbon is selected as the negative electrode sheet, and a solid electrolyte membrane Li6PS5Cl prepared using PTFE as a binder is selected as the solid electrolyte layer.
[00145] Embodiment 5
[00146] The solid-state battery comprises a battery cell.
[00147] In embodiment 5, the process of assembling the battery cell into a solid-state battery includes: isostatic pressing, tongue welding, and final encapsulation. The isostatic pressing parameters in the assembly process are 500 MPa, 15 minutes, and conventional operations are used in other assembly processes.
[00148] In embodiment 5, the battery cells IV in embodiment 4 are assembled into solid-state batteries IV, respectively.In addition, the comparative battery cells I to IV were assembled into comparative solid-state batteries I to IV, respectively.
[00149] Comparative Example 5
[00150] Comparative Example 5 differs from Embodiment 5 in that the battery cell is a multilayer battery cell without encapsulation of the overhang member, i.e., the positive electrode sheet is the positive electrode sheet in a semi-finished state in Embodiment 3 to obtain a comparative solid-state battery V.
[00151] Characterization Test:
[00152] 1. Rheological Property Test of Suspension for 3D Printing of Overhang Members:
[00153] The rheological property of the suspension was measured in a test using a rheometer at room temperature, using a fixture with a 40 mm plate size, a test gap of 150 μm, and a shear rate scanning mode. The rheological property curves of several suspensions are shown in Fig. 4.
[00154] 2.A test was conducted to determine the rheological properties of suspensions IV in embodiments 1 and 2 and comparative suspensions I-IV in comparative examples 1-4 during the actual 3D printing process. Under the conditions of a 3D printing nozzle aperture of 100 μm, a constant extrusion pressure of 0.3 MPa, a straight-line path planning, a line width of 80 μm, a layer height of 20 μm, and a printing speed of 25 mm / s, the test determined the duration of continuous printing without nozzle clogging and the number of nozzle clogging incidents over 10 hours for suspensions IV and comparative suspensions I-IV. The test results are presented in Table 2. suspension continuous printing time (min) number of clogging events (times / 10 hours) suspension I 723 0 suspension II 749 0 suspension III 775 0 IV suspension 681 0 suspension V 674 0 comparative suspension I 587 1 comparative suspension II 516 1 comparative suspension III 394 3 comparative suspension IV 323 4
[00155] It can be seen from Table 2 that the suspensions IV have a longer continuous printing time and a lower number of clogging incidents within 10 hours compared to the comparative suspensions I-IV. Thus, the combination of a two-dimensional layered material with inorganic solid electrolyte particles having multiple particle sizes and a self-assembled lubricating layer formed by a surfactant on the powder surface can significantly improve the rheological properties of the suspensions, increasing the feasibility and efficiency of 3D printing.
[00156] 3. Solid-State Battery Performance Test:
[00157] The solid-state batteries IV in Embodiment 5 and the comparative solid-state batteries I-IV are tested to determine the initial short-circuit probability and cyclic performance.
[00158] The short-circuit probability is determined by testing using a multimeter.The test results are shown in Table 3. Compared with Comparative Example 5 without the overhang structure, the short-circuit probabilities of the solid-state batteries in Embodiments 1 to 5 and Comparative Examples 1 to 4 with the overhang structure are significantly reduced. The short-circuit probabilities of the solid-state batteries produced from the overhang 3D printing slurry containing a two-dimensional material and solid electrolyte particles with different particle sizes in Embodiments 1 to 5 are 0%. This indicates that the overhang made from the overhang 3D printing slurry according to the present invention can significantly reduce the short-circuit problem of the solid-state batteries, improving the yield and safety of the solid-state batteries. Table 3. number of batteries (pcs.) probability of short circuit (%) solid-state battery I 50 0 solid-state battery II 50 0 solid-state battery III 50 0 solid-state battery IV 50 0 solid-state battery V 50 0 Comparative solid-state battery I 50 2 Comparative solid-state battery II 50 4 Comparative solid-state battery III 50 4 comparative solid-state battery IV 50 8 Comparative solid-state battery V 50 38
[00159] Cyclic performance is determined using a test cabinet for charging and discharging batteries. The batteries are assembled in a mold, the voltage range is set to 2.8 V to 4.3 V, the charge / discharge current is set to 0.1 C, and the test is performed to determine the charge / discharge cycle. Process data, such as the gram capacity of the batteries during charging and discharging, are recorded. The test results are presented in Table 4. Table 4 number of batteries (pcs.) gram capacity at the first discharge cycle (mAh / g) capacity retention rate after 100 cycles (%) probability of short circuit after 100 cycles (%) solid-state battery I 50 187 89 2 solid-state battery II 50 189 90 2 solid-state battery III 50 183 87 2 solid-state battery IV 50 179 88 4 solid-state battery V 50 181 90 2 Comparative solid-state battery I 50 172 79 10 Comparative solid-state battery II 50 163 77 14 Comparative solid-state battery III 50 159 71 20 comparative solid-state battery IV 50 151 69 26 Comparative solid-state battery V 50 148 63 54
[00160] From the data provided in Table 4, it can be seen that, compared with the comparative IV solid-state batteries, the IV solid-state batteries have significantly higher capacity retention rates and lower short-circuit probabilities after 100 cycles. Thus, the overhang cell structure according to the present invention can reduce the short-circuit probability in solid-state batteries and improve the cycling performance of the battery. The IV solid-state batteries are manufactured from a 3D-printed overhang cell slurry containing a two-dimensional material in combination with inorganic solid electrolyte particles having multiple particle sizes. Thus, the IV solid-state batteries have better rheological properties and better processability in 3D printing, and the resulting overhang cell has higher density and strength, as well as a more pronounced ability to suppress edge curling and the formation of lithium dendrites.In addition, the synergistic effect generated after high-energy ball milling of the two-dimensional material and the solid electrolyte particles can create a continuous transport path for lithium ions in the overhanging element, equalize the deposition of lithium ions at the edge of the negative electrode, which helps to reduce the formation of lithium dendrites, thereby prolonging the service life and improving the safety of batteries.
[00161] In the embodiments of the present invention, when the final values of the particle size ranges of the first, second, and third inorganic solid electrolyte particles in the inorganic solid electrolyte particles overlap, by default, the maximum final value of the particle size range may not be included, or the minimum final value of the particle size range may not be included, in order to avoid overlapping of the particle size values.
[00162] The above description and drawings fully illustrate some embodiments of the present invention so that those skilled in the art can put them into practice. Other embodiments may include structural, logical, electrical, technological and other changes. The embodiments represent only possible variations. Unless expressly required, individual components and functions are optional, and the sequence of operations may change. Parts and features of some embodiments may be included or replaced by parts and features of other embodiments. Moreover, the words used in the present invention are intended to describe embodiments and do not limit the claims.As used in the description of embodiments and the claims, unless the context clearly indicates otherwise, the singular forms "a" and "an" are intended to include the plural forms. Also, "and / or" in the context of this application refers to any possible combination of one or more related listed items. Furthermore, when used in this invention, the term "comprises" and its variants "comprise" and / or "comprising" indicate the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Without further limitation, an element defined by the statement "includes..." does not exclude the existence of other identical elements in a process, method, or device that may include the element.In this document, each embodiment may highlight differences from other embodiments, and the same or similar parts between different embodiments may refer to each other. For methods, products, etc., disclosed in the embodiments, if they correspond to parts of the methods disclosed in the embodiments, the corresponding information can be found in the description of the parts of the method.
[00163] Those skilled in the art can understand that the blocks and steps in the examples described in connection with the embodiments disclosed herein can be implemented using electronic hardware or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific applications and design limitations of the technical solution.Those skilled in the art may use different methods to implement the described functions for each specific application, but such implementation should not be considered as going beyond the scope of the embodiments of the present invention. Those skilled in the art may clearly understand that, for convenience and brevity of description, specific operational processes of the systems, devices and blocks described above may refer to the corresponding processes in the above-mentioned embodiments of the method, and will not be repeated here.
[00164] The block diagram and block diagrams in the figures show a possible implementation architecture, functions and operations of the systems, methods and computer program products according to embodiments of the present invention. In this regard, each block in the block diagram or block diagram may represent a module, a program segment or a portion of code containing one or more executable instructions for implementing a specific logical function.In some alternative embodiments, the functions indicated in the blocks may also occur in an order different from that shown in the drawings. For example, two successive blocks may be performed substantially simultaneously, or they may sometimes be performed in reverse order, depending on the functions involved. In descriptions corresponding to the flowchart and block diagrams in the drawings, operations or steps corresponding to different blocks may also occur in an order different from that disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two successive operations or steps may be performed substantially simultaneously, or they may sometimes be performed in reverse order, depending on the functions involved.Each block in the block diagrams and / or flow chart, and combinations of blocks in the block diagrams and / or flow chart, may be implemented using a specialized hardware-based system that performs specific functions or actions, or using a combination of specialized hardware and computer instructions.
Claims
1. A suspension for 3D printing of overhanging elements, characterized in that it contains: composite powders, binder, surfactant and solvent; wherein the mass ratio of composite powders to binder is 4-20:1, the mass ratio of surfactant to binder is 0.0005-0.02:1, and the solids percentage of the 3D printing suspension for overhanging elements is 60-75%; the composite powders contain inorganic particles of a solid electrolyte and two-dimensional layered powders, the mass ratio of the inorganic particles of the solid electrolyte and the two-dimensional layered powders is 0.5-1.5:1, the range of particle size distribution of each of the inorganic particles of the solid electrolyte is 0.01-2 μm, the mass fraction of the first inorganic particles of the solid electrolyte with a particle size of each of the first inorganic particles of the solid electrolyte in the range of 0.01-0.3 μm is 25-50%, the two-dimensional size of each of the two-dimensional layered powders is 0.6-2 μm, and Some of the inorganic solid electrolyte particles are embedded in the intermediate layer and / or surface of the sheet layer of the two-dimensional layered powders.
2. A suspension for 3D printing of overhanging elements according to paragraph 1, characterized in that in the inorganic particles of the solid electrolyte, the mass fraction of the second inorganic particles of the solid electrolyte with a particle size of each of the second inorganic particles of the solid electrolyte in the range of 0.3-0.6 μm is 40-75%; and / or in the inorganic particles of the solid electrolyte, the mass fraction of the third inorganic particles of the solid electrolyte with a particle size of each of the third inorganic particles of the solid electrolyte in the range of 0.6-2 μm is 0-20%; when the mass fraction of the third inorganic solid electrolyte particles is not equal to 0, the inorganic solid electrolyte particles contain the first inorganic solid electrolyte particles, the second inorganic solid electrolyte particles and the third inorganic solid electrolyte particles, and the sum of the mass fraction of the first inorganic solid electrolyte particles, the mass fraction of the second inorganic solid electrolyte particles and the mass fraction of the third inorganic solid electrolyte particles is 100%.
3. A suspension for 3D printing of overhanging elements according to paragraph 2, characterized in that the ratio of the particle sizes of each of the second inorganic particles of the solid electrolyte in the range of 0.3-0.6 μm and each of the first inorganic particles of the solid electrolyte is 1:0.03-0.4; and / or the ratio of the particle sizes of each of the third inorganic particles of the solid electrolyte in the range of 0.6-2 μm and each of the second inorganic particles of the solid electrolyte in the range of 0.3-0.6 μm is 1:0.25-0.6; and / or the mass ratio of the second inorganic particles of the solid electrolyte with a particle size of each of the second inorganic particles of the solid electrolyte in the range of 0.3-0.6 μm and the first inorganic particles of the solid electrolyte is 4-7:3-6; and / or the mass ratio of the third inorganic particles of the solid electrolyte with the particle size of each of the third inorganic particles of the solid electrolyte in the range of 0.6-2 μm, the second inorganic particles of the solid electrolyte with the particle size of each of the second inorganic particles of the solid electrolyte in the range of 0.3-0.6 μm and the first inorganic particles of the solid electrolyte is 0-2:4-7:3-6; and the third inorganic particles of the solid electrolyte are not equal to 0.
4. A suspension for 3D printing of overhanging elements according to paragraph 1, characterized in that the inorganic solid electrolyte particles comprise one or more of an oxide-based solid electrolyte particle, a halide-based solid electrolyte particle, a sulfide-based solid electrolyte particle, a hydride-based solid electrolyte particle, and a nitride-based solid electrolyte particle; and / or two-dimensional layered powders include two-dimensional layered thermally conductive powders; and / or the two-dimensional layered powders comprise one or more of a two-dimensional layered nitride inorganic material, a layered silicate material, a layered sulfide, and a two-dimensional metal-organic framework; and / or the two-dimensional layered powders comprise one or more of hexagonal boron nitride, two-dimensional layered aluminum nitride, two-dimensional layered carbon nitride, montmorillonite, MXene, molybdenum disulfide, tungsten disulfide, and a two-dimensional metal-organic framework; and / or the binder comprises one or more of polyvinylidene fluoride, nitrile rubber, butadiene rubber, styrene-butadiene rubber, poly(propylene carbonate), poly(tert-butyl acrylate), poly(ethylene glycol) diacrylate, poly(ethylene oxide), poly(ethylene methyl acrylate), poly(methyl methacrylate), poly(ethylene glycol) diacrylate, polyacrylonitrile, polyisobutylene, poly(ethylene vinyl acetate) and derivatives thereof; and / or the solvent comprises one or more of N,N-dimethylacetamide, N-methylpyrrolidone, acetonitrile, toluene, xylene, butyl butyrate, isobutyl butyrate, ethyl acetate, chloroform, tetrahydrofuran and alkanes; and / or the surfactant comprises one or more of a linear alkyl primary thiol, polyethylene glycol octylphenyl ether, polysorbate 20, sorbitan monooleate, oleic acid, stearic acid, and a hydroxy-functionalized alkyl ammonium salt.
5. A suspension for 3D printing of overhanging elements according to any of paragraphs 1-4, characterized in that it additionally contains a lithium salt; wherein the weight ratio of the lithium salt to the binder is 0.05-0.15:
1.
6. A suspension for 3D printing of overhanging elements according to paragraph 5, characterized in that the mass ratio of lithium salt to binder is 0.08-0.12:1 or 0.1:1; and / or The lithium salt includes one or more of lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium difluoro(oxalato)borate, lithium bis(oxalato)borate, and lithium trifluoromethanesulfonate.
7. A suspension for 3D printing of overhanging elements according to any of paragraphs 1-4, characterized in that the mass ratio of composite powders to binder is 4-18:1, 5-15:1, 8-12:1 or 9-10:1; and / or the mass ratio of surfactant to binder is 0.001-0.02:1, 0.005-0.02:1 or 0.01-0.02:
1.
8. An electrode sheet, characterized in that it contains: positive electrode sheet or negative electrode sheet; and when the electrode sheet comprises a positive electrode sheet, the positive electrode sheet comprises an uncoated foil portion, and the 3D printing slurry of the overhanging elements is located on the uncoated foil portion; when the electrode sheet comprises a negative electrode sheet, the negative electrode sheet comprises an overhang portion, and the 3D printing slurry for overhanging elements is located on the overhang portion of the negative electrode sheet; when the electrode sheet comprises a negative electrode sheet, which is a negative electrode composite sheet, comprising a solid electrolyte layer located on each of the two side surfaces of the negative electrode sheet, the 3D printing slurry of overhanging elements is located on the surface of the solid electrolyte layer of the negative electrode composite sheet corresponding to the overhang portion of the negative electrode sheet; and wherein the suspension for 3D printing of overhanging elements is a suspension for 3D printing of overhanging elements according to any of paragraphs 1-7.
9. A battery element, characterized in that it contains: alternately laid sheets of the positive electrode and sheets of the negative electrode; and one of the solid electrolyte layers is located between each adjacent sheet of the positive electrode and one of the sheets of the negative electrode; each of the sheets of the negative electrode extends beyond each of the sheets of the positive electrode on at least one side in the peripheral direction to form an overhang section; the encapsulation structure is located in the section of the gap for the overhanging element corresponding to the overhang section; the encapsulation structure is obtained by placing the 3D printing slurry for overhanging elements in the gap section for the overhanging element, and the 3D printing slurry for overhanging elements is the 3D printing slurry for overhanging elements according to any one of claims 1-7.
10. A battery element according to paragraph 9, characterized in that the positive electrode sheet comprises an uncoated foil portion, and the 3D printing slurry for overhanging features is located on the uncoated foil portion; or the negative electrode sheet comprises an overhang portion, and the 3D printing slurry for overhanging elements is located on the overhang portion of the negative electrode sheet; or the negative electrode sheet is a composite negative electrode sheet containing a solid electrolyte layer located on each of the two side surfaces of the negative electrode sheet, the 3D printing suspension of overhanging elements is located on the surface of the solid electrolyte layer of the composite negative electrode sheet corresponding to the overhang section of the negative electrode sheet.
11. A solid-state battery, characterized in that it contains an electrode sheet according to paragraph 8 or a battery element according to paragraph 9 or 10.
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