3D printing overhang slurry, electrode plate, battery cell and preparation method thereof and solid-state battery

Abstract

The present application relates to the field of solid-state battery technology and discloses a 3D printing overhang slurry comprising: a composite powder, a binder, a surfactant, and a solvent, wherein the composite powder comprises inorganic solid electrolyte particles with a particle size distribution range of 0.01 to 2 μm and a two-dimensional layered powder with a two-dimensional size of 0.6 to 2 μm, and the mass percentage of particles with a particle size range of 0.01 to 0.3 μm is 25% to 50%; some inorganic solid electrolyte particles are embedded in the interlayers and / or sheet surfaces of the two-dimensional layered powder. The 3D printing overhang slurry takes into account both high solid content and rheological properties, making it suitable for 3D printing methods, achieving the printability and high strength of high-solid content slurries, that is, ensuring both printing strength and smoothness of printing, so that a packaging structure with the desired effect can be obtained in the gaps. The present application also discloses an electrode plate, a battery cell, a preparation method thereof, and a solid-state battery.

Description

Technical Field

[0001] The present application relates to the field of solid-state battery technology, for example, to a 3D printed overhang slurry, an electrode plate, a battery cell and a preparation method thereof, and a solid-state battery. Background Art

[0002] The negative electrode overhang area refers to the portion of the negative electrode sheet that exceeds the positive electrode sheet in the length and / or width direction. This design is mainly to prevent lithium ions from precipitating on the surface of the negative electrode to form lithium dendrites during charging, thereby piercing the diaphragm and causing a short circuit in the battery, triggering thermal runaway, and improving the safety of the battery. However, since all-solid-state batteries usually require a higher assembly pressure during the preparation process. When using traditional plates with a large negative electrode and a small positive electrode, when pressurizing and assembling solid-state batteries, due to the different sizes of the positive and negative electrode plates and uneven force, it is easy to cause the negative electrode overhang area to collapse, and the positive and negative electrodes to contact, resulting in a battery short circuit.

[0003] To address the problem of the negative electrode overhang area easily collapsing during the solid-state battery assembly process, causing contact between the positive and negative electrodes and subsequently causing a battery short circuit, most methods use a method of providing support by placing / filling materials in the overhang gap corresponding to the negative electrode overhang area to prevent the negative electrode overhang area from collapsing during the solid-state battery assembly process. Currently, the methods for placing / filling materials in the overhang gap generally include coating and pouring methods, but these methods cannot effectively control the amount of material placed / filled during the placement / filling process, resulting in the overhang gap filling failing to achieve the desired effect.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0005] In order to provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not an extensive review, nor is it intended to identify key / critical elements or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0006] The embodiments of the present disclosure provide a 3D printed overhang slurry, an electrode plate, a battery cell, a preparation method thereof, and a solid-state battery. The 3D printed overhang slurry can be applied to a 3D printing method, and the 3D printing method can accurately control printing parameters such as the output amount, thereby achieving the expected overhang gap filling effect.

[0007] In some embodiments, the 3D printing overhang slurry includes: a composite powder, a binder, a surfactant and a solvent, the mass ratio of the composite powder to the binder is 4 to 20:1, the mass ratio of the surfactant to the binder is 0.0005 to 0.02:1, and the solid content of the overhang slurry is 60% to 75%; wherein, the composite powder includes inorganic solid electrolyte particles and two-dimensional layered powder, wherein the mass ratio of the inorganic solid electrolyte particles to the two-dimensional layered powder is 0.5 to 1.5:1, and the particle size distribution range of the inorganic solid electrolyte particles is 0.01 to 2 μm, wherein the mass percentage of the first inorganic solid electrolyte particles with a particle size in the range of 0.01 to 0.3 μm is 25% to 50%; the two-dimensional size of the two-dimensional layered powder is 0.6 to 2 μm; some inorganic solid electrolyte particles are embedded in the interlayer and / or sheet surface of the two-dimensional layered powder.

[0008] In some embodiments, the method for preparing the 3D printing overhang slurry includes: preparing various raw materials according to the aforementioned 3D printing overhang slurry; ball-milling and mixing the inorganic solid electrolyte particles and the two-dimensional layered powder to obtain a composite powder; and mixing the composite powder with other raw materials to obtain the 3D printing overhang slurry.

[0009] In some embodiments, the electrode plate is a positive electrode plate or a negative electrode plate; when the electrode plate includes a positive electrode plate, the positive electrode plate includes a hollow foil area, and the hollow foil area is provided with a 3D printed overhang slurry; when the electrode plate includes a negative electrode plate, the negative electrode plate includes an overhang area, and the overhang area of ​​the negative electrode plate is provided with a 3D printed overhang slurry; the electrode plate includes a negative electrode plate and a combined negative electrode plate having a solid electrolyte layer on both sides of the negative electrode plate, and a 3D printed overhang slurry is provided on the surface of the solid electrolyte layer of the combined negative electrode plate corresponding to the overhang area of ​​the negative electrode plate; wherein the 3D printed overhang slurry is the aforementioned 3D printed overhang slurry or a 3D printed overhang slurry prepared by the aforementioned method for preparing the 3D printed overhang slurry.

[0010] In some embodiments, the battery cell includes alternatingly stacked positive electrode sheets and negative electrode sheets, and a solid electrolyte layer is arranged between adjacent positive electrode sheets and negative electrode sheets; at least one side of the negative electrode sheet extends beyond the positive electrode sheet to form an overhang area; wherein a packaging structure is provided in the overhang gap area corresponding to the overhang area; wherein the packaging structure is obtained by arranging a 3D printed overhang slurry in the overhang gap area; the 3D printed overhang slurry is the aforementioned 3D printed overhang slurry or a 3D printed overhang slurry prepared by the aforementioned method for preparing the 3D printed overhang slurry.

[0011] In some embodiments, the preparation method of the battery cell includes: preparing a positive electrode sheet, a negative electrode sheet and a solid electrolyte layer; wherein the size of the negative electrode sheet is larger than the size of the positive electrode sheet on at least one circumferential side, so that the negative electrode sheet has an overhang area; wherein the positive electrode sheet adopts the aforementioned positive electrode sheet, or the negative electrode sheet adopts the aforementioned negative electrode sheet or a combination of negative electrode sheets; the positive electrode sheets and the negative electrode sheets are alternately stacked, and a solid electrolyte layer is provided between adjacent positive electrode sheets and negative electrode sheets to obtain a battery cell; wherein the overhang gap of the battery cell is provided with a solidified 3D printed overhang slurry.

[0012] In some embodiments, the solid-state battery includes: the aforementioned electrode plate; or the aforementioned battery cell; or a battery cell prepared by the aforementioned battery cell preparation method.

[0013] The 3D printed overhang slurry, electrode sheet, battery cell, preparation method thereof, and solid-state battery provided in the embodiments of the present disclosure can achieve the following technical effects:

[0014] The 3D printing overhang slurry of the disclosed embodiment takes into account both high solid content and rheological properties, making it suitable for 3D printing methods, achieving the printability and high strength of the high solid content slurry, that is, ensuring the printing strength and the smoothness of the printing, so that the packaging structure with the expected effect can be obtained at the overhang gap. At the same time, the inorganic solid electrolyte particles with a large particle size distribution range are compounded with the two-dimensional layered powder. Then, the inorganic solid electrolyte particles that are adapted to the interlayer spacing and the surface defects of the two-dimensional layered powder can be embedded in the interlayer and / or layer surface of the two-dimensional layered powder. Then, the surface defects of the two-dimensional layered powder provide affinity sites for lithium ions, and the synergistic embedded inorganic solid electrolyte particles construct a continuous lithium ion transmission path, reducing the short circuit risk and capacity loss caused by lithium precipitation at the edge of the negative electrode, and achieving the expected effect of filling the overhang gap.

[0015] In the preparation method of the 3D printing overhang slurry of the embodiment of the present disclosure, the inorganic solid electrolyte particles and the two-dimensional layered powder are mixed by ball milling to obtain a composite powder, and then the composite powder is mixed with other raw materials. During the ball milling process, the strong collision and friction between the inorganic solid electrolyte particles and the two-dimensional thermal conductive material will further construct rich 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 grinding shear force, the amount of inorganic solid electrolyte particles embedded in the interlayer and / or sheet surface of the two-dimensional layered powder can be increased, thereby synergistically constructing a better continuous lithium ion transmission path, reducing the short circuit risk and capacity loss caused by lithium precipitation at the edge of the negative electrode side.

[0016] The electrode plates of the disclosed embodiment can be printed to set up an overhang packaging structure through a 3D printing method, and the printing volume can be precisely controlled, thereby being able to well control parameters such as the thickness and uniformity of the packaging structure, with fast printing speed and high efficiency.

[0017] The above general description and the following description are exemplary and explanatory only and are not intended to limit the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] One or more embodiments are exemplarily described by corresponding drawings. These exemplary descriptions 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 constitute a scale limitation. In addition,

[0019] Figure 1 1 is a schematic structural diagram of a portion of a composite powder in a 3D printing overhang slurry provided by an embodiment of the present disclosure;

[0020] Figure 2 This is a flowchart of a method for preparing a 3D printing overhang slurry provided by an embodiment of the present disclosure;

[0021] Figure 3 This is a flowchart of a method for preparing a battery cell provided by an embodiment of the present disclosure;

[0022] Figure 4 3D printing overhang slurry rheological properties curve provided by the embodiment of the present disclosure.

[0023] Reference numerals:

[0024] 11. Two-dimensional layered powder; 12. Inorganic solid electrolyte particles. DETAILED DESCRIPTION

[0025] In order to be able to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure is described in detail below in conjunction with the accompanying drawings. The accompanying drawings are for reference only and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of convenience of explanation, a full understanding of the disclosed embodiments is provided through multiple details. However, one or more embodiments can still be implemented without these details. In other cases, to simplify the drawings, well-known structures and devices can be simplified for display.

[0026] In the description and claims of the embodiments of the present disclosure, as well as in the accompanying drawings, the terms "first," "second," and the like are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate to facilitate understanding of the embodiments of the present disclosure described herein. In addition, the terms "including," "having," and any variations thereof are intended to cover non-exclusive inclusions.

[0027] In the embodiments of the present disclosure, the terms "upper", "lower", "inside", "middle", "outside", "front", "back" and the like indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. These terms are mainly intended to better describe the embodiments of the present disclosure and their embodiments, and are not intended to limit the indicated devices, elements or components to having a specific direction, or to be constructed and operated in a specific direction. Moreover, in addition to being used to indicate directions or positional relationships, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in certain circumstances. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0028] Furthermore, the terms "disposed," "connected," and "fixed" should be interpreted broadly. For example, "connected" can mean a fixed connection, a removable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediary, or an internal connection between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the embodiments of this disclosure based on the specific circumstances.

[0029] Unless otherwise stated, the term "plurality" means two or more.

[0030] In the embodiment of the present disclosure, the character " / " indicates that the preceding and following objects are in an "or" relationship. For example, A / B means: A or B.

[0031] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0032] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0033] Combine Figure 1 As shown, an embodiment of the present disclosure provides a 3D printing overhang slurry, including: a composite powder, a binder, a surfactant and a solvent, the mass ratio of the composite powder to the binder is 4 to 20:1, the mass ratio of the surfactant to the binder is 0.0005 to 0.02:1, and the solid content of the overhang slurry is 60% to 75%; wherein, the composite powder includes inorganic solid electrolyte particles and two-dimensional layered powder, wherein the mass ratio of the inorganic solid electrolyte particles to the two-dimensional layered powder is 0.5 to 1.5:1; the particle size distribution range of the inorganic solid electrolyte particles is 0.01 to 2 μm, wherein the mass percentage of the first inorganic solid electrolyte particles with a particle size in the range of 0.01 to 0.3 μm is 25% to 50%; the two-dimensional size of the two-dimensional layered powder is 0.6 to 2 μm; some inorganic solid electrolyte particles 12 are embedded in the interlayer and / or sheet surface of the two-dimensional layered powder 11.

[0034] The 3D printing overhang slurry of the disclosed embodiment takes into account both high solid content and rheological properties, making it suitable for 3D printing methods, achieving the printability and high strength of the high solid content slurry, that is, ensuring the printing strength and the smoothness of the printing, so that the packaging structure with the expected effect can be obtained at the overhang gap. At the same time, the inorganic solid electrolyte particles with a large particle size distribution range are compounded with the two-dimensional layered powder. Then, the inorganic solid electrolyte particles that are adapted to the interlayer spacing and the surface defects of the two-dimensional layered powder can be embedded in the interlayer and / or layer surface of the two-dimensional layered powder. Then, the surface defects of the two-dimensional layered powder provide affinity sites for lithium ions, and the synergistic embedded inorganic solid electrolyte particles construct a continuous lithium ion transmission path, reducing the short circuit risk and capacity loss caused by lithium precipitation at the edge of the negative electrode, and achieving the expected effect of filling the overhang gap.

[0035] The 3D printing overhang slurry of the disclosed embodiments has a solid content of 60% to 75%, a very high solid content. The combination of inorganic solid electrolyte particles of varying particle sizes and a two-dimensional material, along with surfactant regulation, significantly improves the slurry's rheological properties, resulting in a 3D printing overhang slurry with this solid content that achieves a balance between rheological properties and high solids content. This results in a reasonable number of solid phase particles and appropriate interparticle spacing in the 3D printing overhang slurry, resulting in optimal rheological properties, making it suitable for 3D printing methods, ensuring the processability and stability of 3D printing, and ensuring the strength and density of the printed overhang packaging structure. It is understood that the solid content of the 3D printing overhang slurry can be expressed in terms of either mass or volume, with no limitation. Alternatively, the solid content of the 3D printing overhang slurry can be expressed in terms of mass. Adjustment of the solid content is achieved by adjusting the amount of solvent added; that is, the amount of solvent used in the 3D printing overhang slurry of the disclosed embodiments is determined based on the slurry's solid content. The type of solvent is not limited.

[0036] Optionally, the solvent includes one or more of N,N-dimethylacetamide, N-methylpyrrolidone, acetonitrile, toluene, xylene, butyl butyrate, butyl isobutyrate, ethyl acetate, chloroform, tetrahydrofuran and alkanes.

[0037] Optionally, the solid content of the 3D printing overhang slurry is 60% to 70%. Optionally, the solid content of the 3D printing overhang slurry is 60% to 65%.

[0038] Optionally, the solid content of the 3D printing overhang slurry is 60%, 62%, 65%, 70% or 75%, or any value within the range of 60% to 75%.

[0039] The viscosity of the 3D printing overhang slurry in the embodiment of the present disclosure is 2-10 Pa·s -1 . Low viscosity and good rheological properties.

[0040] In the 3D printing overhang slurry of the disclosed embodiment, by controlling the mass percentage of the first inorganic solid electrolyte particles with a particle size in the range of 0.01 to 0.3 μm, the amount of the first inorganic solid electrolyte particles in the small particle size range is ensured, so that at least a portion of the nano-scale first inorganic solid electrolyte particles can be embedded in the interlayer and / or sheet surface of the two-dimensional layered powder, so that the small nano-inorganic solid electrolyte particles act as a "bridge" between the two-dimensional layered materials, and the anisotropy of the two-dimensional material complements the random orientation of the nano-scale inorganic solid electrolyte particles to achieve a quasi-isotropic ion-conducting functional three-dimensional network, effectively reducing the ion transport obstacles inside the battery and improving the safety and cycle life of the battery. In addition, the small-particle-size solid electrolyte particles can flow in the gaps between the large-particle-size solid electrolyte particles, weakening the flow resistance between the particles, further reducing the slurry viscosity and improving the slurry rheological properties. In addition, the two-dimensional layered thermal conductive material can also be used as a lubricant and combined with a combination of inorganic solid electrolyte particles of different particle sizes to improve the rheological properties of the slurry, which is beneficial for constructing a continuous ion transmission path in the Overhang voids after molding and improving the density and strength of the Overhang packaging structure.

[0041] Optionally, the mass percentage of the first inorganic solid electrolyte particles is 30% to 50%. Optionally, the mass percentage of the first inorganic solid electrolyte particles is 30% to 40%. Optionally, the mass percentage of the first inorganic solid electrolyte particles is 25%, 30%, 35%, 40%, 45%, 50%, or any value within the range of 25% to 50%. It will be understood that the mass percentage of the first inorganic solid electrolyte particles refers to the mass percentage of the first inorganic solid electrolyte particles to all inorganic solid electrolyte particles.

[0042] Among the inorganic solid electrolyte particles, except for the first inorganic solid electrolyte, the particle size of the remaining inorganic solid electrolyte particles ranges from 0.3 to 2 μm. The particle size of the inorganic solid electrolyte particles within this particle size range is not limited and can be determined according to actual conditions.

[0043] In some embodiments, the mass percentage of the second inorganic solid electrolyte particles with a particle size in the range of 0.3 to 0.6 μm is 40% to 75% of the inorganic solid electrolyte particles. In this embodiment, the proportion of the second inorganic solid electrolyte particles with a particle size in the range of 0.3 to 0.6 μm is limited so that they are compounded with the first inorganic solid electrolyte particles in the smaller particle size range to further improve the rheological properties of the slurry, construct a more optimal continuous ion transport path, and further improve the density and strength of the Overhang packaging structure.

[0044] Optionally, the composite powder is obtained by grinding and mixing inorganic solid electrolyte particles and two-dimensional layered powder. Through grinding, for example, ball milling, the strong collision and friction between the inorganic solid electrolyte particles and the two-dimensional thermal conductive material will further construct rich 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 grinding shear force, the amount of inorganic solid electrolyte particles embedded in the interlayer and / or sheet surface of the two-dimensional layered powder can be increased, thereby synergistically constructing a better continuous lithium ion transmission path, reducing the short circuit risk and capacity loss caused by lithium precipitation at the edge of the negative electrode side.

[0045] Alternatively, the composite powder is obtained by mixing the inorganic solid electrolyte particles and the two-dimensional layered powder by ball milling. Alternatively, the composite powder is obtained by high-energy ball milling. The ball milling parameters are determined according to actual needs.

[0046] Optionally, the ball milling parameters include: a ball to material ratio of 10 to 40:1; and / or a rotation speed of 400 to 600 rpm; and / or a ball milling time of 1 to 2 hours. Optionally, the ball to material ratio is 20 to 40:1.

[0047] Optionally, the inorganic solid electrolyte particles are composed of a first inorganic solid electrolyte and a second inorganic solid electrolyte, that is, the particle size distribution range of the inorganic solid electrolyte particles is 0.01 to 0.6 μm. In this embodiment, the inorganic solid electrolyte particles are two-stage particle size composite particles, defined as two-stage composite inorganic solid electrolyte particles. In this embodiment, the mass percentage of the first inorganic solid electrolyte is 25% to 50%, and the mass percentage of the second inorganic solid electrolyte particles is 50% to 75%.

[0048] Optionally, in the two-stage composite inorganic solid electrolyte particles, the mass ratio of the second inorganic solid electrolyte particles to the first inorganic solid electrolyte particles is (4-7):(3-6). Optionally, the mass ratio of the second inorganic solid electrolyte particles to the first inorganic solid electrolyte particles is (5-6):(3-4).

[0049] Optionally, in the two-stage composite inorganic solid electrolyte particles, the mass percentage of the first inorganic solid electrolyte is 30% to 50%, and the mass percentage of the second inorganic solid electrolyte particles is 50% to 70%.

[0050] Optionally, in the two-stage composite inorganic solid electrolyte particles, the mass percentage of the first inorganic solid electrolyte is 30% to 40%, and the mass percentage of the second inorganic solid electrolyte particles is 60% to 70%.

[0051] Optionally, in the two-stage composite inorganic solid electrolyte particles, the particle size ratio of the second inorganic solid electrolyte particles to the first inorganic solid electrolyte particles (defined as the first particle size ratio) is 1:0.03-0.4. That is, the specific particle sizes of the second inorganic solid electrolyte particles and the first inorganic solid electrolyte particles are determined within this particle size ratio range. Optionally, the first particle size ratio is 1:0.03-0.3; alternatively, the first particle size ratio is 1:0.03-0.2. Alternatively, 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, among others. By defining the first particle size ratio, the rheological properties of the slurry are further improved, a more optimal continuous ion transport path is constructed, and the density and strength of the overhang packaging structure are further enhanced.

[0052] In some embodiments, among the inorganic solid electrolyte particles, the third inorganic solid electrolyte particles have a particle size in the range of 0.6 to 2 μm, and the mass percentage of the third inorganic solid electrolyte particles is 0 to 20% and is not 0. In this embodiment, among the inorganic solid electrolyte particles, the mass percentage of the second inorganic solid electrolyte particles with a particle size in the range of 0.3 to 0.6 μm is not limited, as long as the sum of the first inorganic solid electrolyte particles, the second inorganic solid electrolyte particles, and the third inorganic solid electrolyte particles is 100%. The inorganic solid electrolyte particles of this embodiment are defined as three-stage composite inorganic solid electrolyte particles.

[0053] In the three-stage composite inorganic solid electrolyte particles of this embodiment, the mass percentage of the first inorganic solid electrolyte particles is 25% to 50%, the mass percentage of the second inorganic solid electrolyte particles is 40% to 75%, and the mass percentage of the third inorganic solid electrolyte particles is 0 to 20% and is not 0; and the sum of the three is 100%.

[0054] Optionally, in the three-stage composite inorganic solid electrolyte particles, the mass 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 0. Optionally, the mass 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).

[0055] Optionally, in the three-stage composite inorganic solid electrolyte particles, the mass percentage of the first inorganic solid electrolyte particles is 25% to 50%, the mass percentage of the second inorganic solid electrolyte particles is 40% to 60%, and the mass percentage of the third inorganic solid electrolyte particles is 0% to 20% and is not 0.

[0056] Optionally, in the three-stage composite inorganic solid electrolyte particles, the mass percentage of the first inorganic solid electrolyte particles is 25% to 40%, the mass percentage of the second inorganic solid electrolyte particles is 40% to 60%, and the mass percentage of the third inorganic solid electrolyte particles is 5% to 20%.

[0057] Optionally, in the three-stage composite inorganic solid electrolyte particles, the mass percentage of the first inorganic solid electrolyte particles is 30% to 40%, the mass percentage of the second inorganic solid electrolyte particles is 45% to 60%, and the mass percentage of the third inorganic solid electrolyte particles is 10% to 20%.

[0058] In the three-stage composite inorganic solid electrolyte particles, the particle size ratio of the third inorganic solid electrolyte particles to the second inorganic solid electrolyte particles (defined as the second particle size ratio) is 1:0.25~0.6; the particle size ratio of the second inorganic solid electrolyte particles to the first inorganic solid electrolyte particles (the same as the aforementioned first particle size ratio) is 1:0.03~0.4.

[0059] Optionally, the second particle size ratio is 1:0.3 to 0.5. Optionally, the second particle size ratio is 1:0.35 to 0.45. Optionally, the second particle size ratio is 1:0.4. Optionally, 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 slurry are further improved, a more optimal continuous ion transport path is constructed, and the density and strength of the overhang packaging structure are further improved.

[0060] In the embodiments of the present disclosure, the type of inorganic solid electrolyte particles is not limited. Alternatively, the inorganic solid electrolyte particles include, but are not limited to, one or more of oxide solid electrolyte particles, halide solid electrolyte particles, sulfide solid electrolyte particles, hydride solid electrolyte particles, and nitride solid electrolyte particles. The type can be determined based on actual needs.

[0061] In the disclosed embodiments, the two-dimensional layered powder comprises a two-dimensional powder having a certain thickness and composed of a plurality of lamellae, with a certain interlamellar spacing between adjacent lamellae, and at least a portion of the first inorganic solid electrolyte particles having a particle size in the range of 0.01 to 0.3 μm being able to be embedded in the interlayers and / or lamellae surfaces of the two-dimensional layered powder. Furthermore, the two-dimensional layered powder generally has surface defects on the two-dimensional lamellae surfaces, and these surface defects cooperate with the embedded inorganic solid electrolyte particles to construct a continuous lithium ion transmission path, reducing the risk of short circuits and capacity loss caused by lithium precipitation at the edge of the negative electrode side, thereby achieving the desired effect of filling the overhang gap.

[0062] Optionally, the two-dimensional layered powder includes a two-dimensional layered thermally conductive powder. The two-dimensional layered thermally conductive powder is not limited as long as it has certain thermal conductivity. In this embodiment, the use of the two-dimensional layered thermally conductive powder can increase the thermal conductivity of the quasi-isotropic ion-conducting functional three-dimensional network constructed with the nano-scale inorganic solid electrolyte particles, that is, a quasi-isotropic ion-conducting and thermally conductive dual-functional three-dimensional network is constructed, which effectively reduces heat concentration and ion transport obstruction inside the battery, thereby improving the safety and cycle life of the battery.

[0063] In some embodiments, the two-dimensional size of the two-dimensional layered powder is 0.8 to 2 μm. Alternatively, the two-dimensional size of the two-dimensional layered powder is 1 to 1.5 μm.

[0064] Optionally, the two-dimensional layered powder (or two-dimensional layered thermally conductive powder) has a powder particle thickness of 0.7 to 20 nm. The thickness refers to the thickness of the two-dimensional layered powder in a direction perpendicular to the two-dimensional direction. The powder particles can be single-layer or multi-layer two-dimensional powders.

[0065] Optionally, the two-dimensional layered powder includes multiple layers of two-dimensional powder (or multiple layers of two-dimensional thermally conductive powder), and the thickness of the powder particles is 2 nm to 20 nm. Optionally, the thickness of the powder particles is 5 nm to 20 nm. Optionally, the thickness of the powder particles is 10 nm to 20 nm.

[0066] In some embodiments, the mass ratio of the inorganic solid electrolyte particles to the two-dimensional layered powder (defined as a first mass ratio) is 0.5 to 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.

[0067] Optionally, the two-dimensional layered powder includes one or more of two-dimensional layered nitride inorganic materials, layered silicate materials, layered sulfides, and two-dimensional metal-organic frameworks, which can be determined based on actual conditions.

[0068] Optionally, the two-dimensional layered nitride inorganic material includes hexagonal boron nitride, two-dimensional layered aluminum nitride or two-dimensional layered carbon nitride.

[0069] Optionally, the layered silicate material comprises montmorillonite.

[0070] Optionally, the layered sulfide includes molybdenum disulfide or tungsten disulfide.

[0071] Optionally, the two-dimensional layered powder includes 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 framework.

[0072] In the 3D printing overhang slurry of the disclosed embodiments, a binder is used to bond the composite powder. By controlling the ratio of the composite powder to the binder, the slurry can have rheological properties suitable for 3D printing methods, thereby ensuring the stability of the resulting overhang packaging structure, as well as heat dissipation and ion transport functions. Therefore, a controlled mass ratio of the composite powder to the binder of (4-20):1 is sufficient.

[0073] Optionally, the mass ratio of the composite powder to the binder is (4-18):1. Optionally, the mass ratio of the composite powder to the binder is (5-15):1. Optionally, the mass ratio of the composite powder to the binder is (8-12):1. Optionally, the mass ratio of the composite powder to the binder is (9-10):1.

[0074] In some embodiments, the binder includes but is not limited to one or more of polyvinylidene fluoride, nitrile rubber, butadiene rubber, styrene-butadiene rubber, polypropylene carbonate, poly-tert-butyl acrylate, polyethylene glycol diacrylate, polyethylene oxide, polyethylene methacrylate, polymethyl methacrylate, polyethylene glycol diacrylate, polyacrylonitrile, polyisobutylene, polyethylene vinyl acetate and their derivatives.

[0075] In the 3D printing overhang slurry of the disclosed embodiments, the surfactant can reduce the interfacial tension between the slurry and the printed substrate (e.g., the hollow foil area of ​​the positive electrode sheet, or the overhang area of ​​the negative electrode sheet) and the side (or end) surface of the electrode, improving the wettability of the slurry, increasing the bonding strength between the overhang and the side (or end) surface of the electrode and between layers, and enhancing the stability of the overhang packaging structure. At the same time, the surfactant can form a self-assembled lubricating layer on the surface of the inorganic solid electrolyte particles and the two-dimensional layered powder (or two-dimensional layered thermal conductive powder), reducing the friction between the particles and improving the dispersion uniformity and rheological properties of the slurry. The proportion of surfactant in the slurry needs to be controlled. For example, the mass ratio of surfactant to binder is (0.0005-0.02):1. The proportion of surfactant in the slurry should not be too large, otherwise it will easily make the slurry too fluid and make it difficult to maintain the shape fidelity of the printed structure. In addition, bubbles are easily generated in the slurry, affecting the density of the print and the strength after molding.

[0076] Optionally, the mass ratio of the surfactant to the binder is 0.001 to 0.02: 1. Optionally, the mass ratio of the surfactant to the binder is 0.005 to 0.02: 1. Optionally, the mass ratio of the surfactant to the binder is 0.01 to 0.02: 1.

[0077] Optionally, the mass ratio of the surfactant to the binder is 0.005:1, 0.008:1, 0.01:1, 0.015:1, or 0.02:1.

[0078] Optionally, the surfactant includes one or more of linear alkyl primary mercaptan, polyethylene glycol octylphenyl ether, polysorbate-20, sorbitan monooleate, oleic acid, stearic acid, and hydroxyl functionalized alkyl ammonium salts.

[0079] In some embodiments, the 3D printing overhang slurry of the disclosed embodiments further includes: a lithium salt; and a mass ratio of the lithium salt to the binder of 0.05 to 0.15:1. In this embodiment, lithium salt is added as a supplementary lithium source in the overhang packaging structure to provide sufficient lithium ions, and cooperates with the interface of the binder, inorganic solid electrolyte particles, and two-dimensional layered materials (or two-dimensional layered thermal conductive powders) to construct a continuous three-dimensional ion transport network. By controlling the amount of lithium salt, a suitable concentration of lithium ions can be provided to ensure the lithium ion transport capacity without affecting the plasticity of the binder, thereby ensuring the strength and stability of the overhang packaging structure.

[0080] Optionally, the mass ratio of the lithium salt to the binder is 0.08 to 0.12: 1. Optionally, the mass ratio of the lithium salt to the binder is 0.1:1.

[0081] Optionally, the lithium salt includes one or more of lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium oxalatodifluoroborate, lithium bis(oxalatoborate), and lithium trifluoromethylsulfonate.

[0082] Combine Figure 2 As shown, the embodiment of the present disclosure provides a method for preparing a 3D printing overhang slurry, comprising the following steps:

[0083] S110. Prepare the raw materials for the 3D printing overhang slurry according to any of the preceding embodiments. In this step S110, the raw materials include at least inorganic solid electrolyte particles, two-dimensional layered powder, a binder, a surfactant, and a solvent. Alternatively, a lithium salt may be included. The amounts of the raw materials used should meet the requirements of the 3D printing overhang slurry according to any of the preceding embodiments.

[0084] S120, ball-milling the inorganic solid electrolyte particles and the two-dimensional layered powder to obtain a composite powder;

[0085] S130: Mix the composite powder with other raw materials to obtain a 3D printing overhang slurry. In this embodiment, the other raw materials include at least a binder, a surfactant, and a solvent; or further include a lithium salt.

[0086] In the method of the embodiment of the present disclosure, the inorganic solid electrolyte particles and the two-dimensional layered powder are mixed by ball milling to obtain a composite powder, and then the composite powder is mixed with other raw materials. During the ball milling process, the strong collision and friction between the inorganic solid electrolyte particles and the two-dimensional layered material (or the two-dimensional layered thermal conductive powder) will further construct rich 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 grinding shear force, the amount of inorganic solid electrolyte particles embedded in the interlayer and / or sheet surface of the two-dimensional layered powder can be increased, thereby synergistically constructing a better continuous lithium ion transmission path, reducing the short circuit risk and capacity loss caused by lithium precipitation at the edge of the negative electrode side.

[0087] Optionally, in step S120, the ball milling parameters include: a ball-to-material ratio of 10 to 40:1; and / or a rotation speed of 400 to 600 rpm; and / or a ball milling time of 1 to 2 hours.

[0088] Optionally, the ball-to-material ratio is 20-40:1.

[0089] In step S130, the composite powder is mixed with other raw materials, including stirring the composite powder and other raw materials. In this embodiment, the stirring and mixing method is determined according to actual conditions.

[0090] An embodiment of the present disclosure provides an electrode plate, which is a positive electrode plate or a negative electrode plate. Wherein, when the electrode plate includes a positive electrode plate, the positive electrode plate includes a hollow foil area, and the hollow foil area is provided with a 3D printed overhang slurry. When the electrode plate includes a negative electrode plate, the negative electrode plate includes an overhang area, and the overhang area of ​​the negative electrode plate is provided with a 3D printed overhang slurry. The electrode plate includes a negative electrode plate and a combined negative electrode plate having a solid electrolyte layer provided on both sides of the negative electrode plate, and a 3D printed overhang slurry is provided on the surface of the solid electrolyte layer of the combined negative electrode plate corresponding to the overhang area of ​​the negative electrode plate. Wherein, the 3D printed overhang slurry is the 3D printed overhang slurry of any of the aforementioned embodiments or the 3D printed overhang slurry prepared by the preparation method of the 3D printed overhang slurry of any of the aforementioned embodiments.

[0091] In the embodiment of the present disclosure, 3D printed overhang slurry is set in the area corresponding to the overhang area of ​​the electrode plate, for example, the empty foil area of ​​the positive electrode plate, the surface of the overhang area of ​​the negative electrode plate, or the surface of the solid electrolyte layer corresponding to the overhang area of ​​the combined negative electrode plate, so that the 3D printed overhang slurry is set in the overhang gap of the stacked battery cell, and the overhang packaging structure is obtained after curing.

[0092] The 3D printing overhang slurry provided on the electrode plate of the embodiment of the present disclosure can be printed and provided using a 3D printing method.

[0093] The 3D printed overhang slurry provided on the electrode plate of the embodiment of the present disclosure can be kept in a slurry state before entering the subsequent process; or the 3D printed overhang slurry can be solidified before entering the subsequent process, which is not limited and is determined according to actual conditions.

[0094] An embodiment of the present disclosure provides a battery cell, comprising alternatingly stacked positive electrode sheets and negative electrode sheets, and a solid electrolyte layer is arranged between adjacent positive electrode sheets and negative electrode sheets; at least one side of the negative electrode sheet extends beyond the positive electrode sheet to form an overhang area; wherein a packaging structure is provided in the overhang gap area corresponding to the overhang area; wherein the packaging structure is obtained by arranging a 3D-printed overhang slurry in the overhang gap area; the 3D-printed overhang slurry is the 3D-printed overhang slurry of any of the aforementioned embodiments or a 3D-printed overhang slurry prepared by the preparation method of the 3D-printed overhang slurry of any of the aforementioned embodiments.

[0095] The battery cell of the embodiment of the present disclosure includes the 3D printed overhang slurry of any of the aforementioned embodiments. The battery cell has all the technical effects of the 3D printed overhang slurry, which will not be repeated here.

[0096] In the battery cell of the disclosed embodiment, the 3D-printed overhang slurry is cured to form the package structure. Curing is the process of evaporating the solvent in the slurry. Therefore, the curing temperature is determined by the type of solvent used. Optionally, the temperature is 60°C to 150°C.

[0097] In some embodiments, the positive electrode plate adopts the positive electrode plate of the electrode plate of any of the aforementioned embodiments; or, the negative electrode plate adopts the negative electrode plate of the electrode plate of any of the aforementioned embodiments or a combined negative electrode plate.

[0098] Combine Figure 3 As shown, the embodiment of the present disclosure provides a method for preparing a battery cell, comprising the following steps:

[0099] S210. Prepare a positive electrode sheet, a negative electrode sheet, and a solid electrolyte layer; wherein the size of the negative electrode sheet is larger than the size of the positive electrode sheet on at least one circumferential side, so that the negative electrode sheet has an overhang area; wherein the positive electrode sheet adopts the positive electrode sheet of any of the aforementioned embodiments, or the negative electrode sheet adopts the negative electrode sheet of any of the aforementioned embodiments or a combination of negative electrode sheets.

[0100] S220. Alternately stacking the positive electrode sheets and the negative electrode sheets, and providing a solid electrolyte layer between adjacent positive electrode sheets and negative electrode sheets, to obtain a battery cell; wherein, a solidified 3D printed overhang slurry is provided in the overhang gap of the battery cell.

[0101] Optionally, in step S210, a positive electrode sheet is prepared, including: setting a positive electrode active slurry on a positive electrode collector to obtain a positive electrode active material layer, and reserving an empty foil area on the positive electrode collector around the positive electrode active material layer; and printing a 3D printed overhang slurry on the empty foil area of ​​the positive electrode sheet by a 3D printing method to obtain a positive electrode sheet.

[0102] Optionally, in step S210, preparing a negative electrode plate includes: placing a negative electrode active slurry on a negative electrode current collector to obtain a negative electrode active material layer, and printing a 3D printing overhang slurry on the surface of the overhang area of ​​the negative electrode plate by a 3D printing method to obtain the negative electrode active material layer.

[0103] Optionally, step S210 further includes: transferring the solid electrolyte layer to the two surfaces of the negative electrode sheet, and printing the 3D printed overhang slurry on the surface of the solid electrolyte layer corresponding to the overhang area of ​​the negative electrode sheet by a 3D printing method to obtain a combined negative electrode sheet.

[0104] Optionally, before alternately stacking the positive and negative electrode sheets in step S220, the process further includes: curing the 3D-printed overhang slurry disposed on the positive or negative electrode sheet to obtain a positive or negative electrode sheet having an encapsulated structure. Alternatively, after alternately stacking the positive and negative electrode sheets in step S220, the process further includes: curing the stacked battery cell structure to obtain a battery cell having an encapsulated structure. The process may be determined based on actual circumstances.

[0105] The embodiments of the present disclosure further provide a solid-state battery, comprising: an electrode plate according to any of the aforementioned embodiments; or a battery cell according to any of the aforementioned embodiments; or a battery cell prepared by the method for preparing a battery cell according to any of the aforementioned embodiments.

[0106] The following specific examples are given to specifically illustrate the 3D printing overhang slurry, electrode pole piece, battery cell and its preparation method and solid-state battery of the embodiment of the present disclosure, so as to more clearly illustrate the technical problems, technical solutions and beneficial effects solved by this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. The following description of at least one exemplary embodiment is actually only illustrative and is in no way intended to limit the present application and its applications.

[0107] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. All reagents or instruments used without specifying the manufacturer are commercially available conventional products.

[0108] Example 1

[0109] A 3D printing overhang slurry includes a composite powder, a binder, a lithium salt, a surfactant, and a solvent. The mass ratio of the composite powder to the binder is 4 to 20:1, the mass ratio of the surfactant to the binder is 0.0005 to 0.02:1, the mass ratio of the lithium salt to the binder is 0.05 to 0.15:1, and the solid content of the overhang slurry is 60% to 75%. The composite powder includes inorganic solid electrolyte particles and two-dimensional layered powder. The mass ratio of the multi-dimensional layered powder is 0.5 to 1.5:1, and the particle size distribution range of the inorganic solid electrolyte particles is 0.01 to 2 μm. The mass percentage of the first inorganic solid electrolyte particles with a particle size range of 0.01 to 0.3 μm is 25% to 50%; the mass percentage of the second inorganic solid electrolyte particles with a particle size range of 0.3 to 0.6 μm is 40% to 60%; and the mass percentage of the third inorganic solid electrolyte particles with a particle size range of 0.6 to 2 μm is 0% to 20% and is not 0. The particle size ratio of the third inorganic solid electrolyte particles to the second inorganic solid electrolyte particles is 1:0.25 to 0.6; and the particle size ratio of the second inorganic solid electrolyte particles to the first inorganic solid electrolyte particles is 1:0.03 to 0.4.

[0110] The two-dimensional size of the two-dimensional layered powder is 0.6 to 2 μm; part of the inorganic solid electrolyte particles are embedded in the interlayers and / or the surface of the sheets of the two-dimensional layered powder.

[0111] The 3D printing overhang slurry of this embodiment 1 is defined as three-stage composite inorganic solid electrolyte particles.

[0112] In Example 1, four specific slurry compositions are described. The inorganic solid electrolyte particles are LATP oxide solid electrolytes, the binder is grafted polyvinylidene fluoride, the lithium salt is lithium bis(trifluoromethylsulfonyl)imide, the surfactant is polyethylene glycol octylphenyl ether, and the solvent is low-boiling-point tetrahydrofuran. The mass ratios of the composite powder, binder, lithium salt, surfactant, and solvent are, in order, 90:10:1:0.2:43. The solids content of the overhang slurry is 60% to 65%. The remaining raw material compositions are shown in Table 1.

[0113] Table 1

[0114]

[0115] The method for preparing the 3D printing overhang slurry of this embodiment 1 includes the following steps:

[0116] According to the 3D printing overhang slurry of Example 1, various raw materials are prepared: inorganic solid electrolyte particles, two-dimensional layered powder, binder, lithium salt, surfactant and solvent.

[0117] The inorganic solid electrolyte particles and the two-dimensional layered powder are mixed by high-energy ball milling to obtain a composite powder; wherein the high-energy ball milling parameters include: a ball-to-material ratio of 40:1; a rotation speed of 500 rpm; and a ball milling time of 1.5 h.

[0118] The composite powder, binder, lithium salt, surfactant and solvent are mixed to obtain a 3D printing overhang slurry.

[0119] In this Example 1, the rheological properties of the 3D printing overhang slurry were tested, such as Figure 4 The rheological properties curve of the 3D printing overhang slurry shown in FIG. 1 shows that the viscosity of the 3D printing overhang slurry (slurry I and slurry II) of Example 1 is 2-10 Pa·s. -1 . Low viscosity and good rheological properties.

[0120] Example 2

[0121] A 3D printing overhang slurry includes a composite powder, a binder, a lithium salt, a surfactant and a solvent, wherein the mass ratio of the composite powder to the binder is 4 to 20:1, the mass ratio of the surfactant to the binder is 0.0005 to 0.02:1, the mass ratio of the lithium salt to the binder is 0.05 to 0.15:1, and the solid content of the overhang slurry is 60% to 75%; wherein the composite powder includes inorganic solid electrolyte particles and two-dimensional layered powder, wherein the mass ratio of the inorganic solid electrolyte particles to the two-dimensional layered powder is 0.5 to 1.5:1, and the particle size distribution range of the inorganic solid electrolyte particles is 0.01 to 0.6 μm, wherein the mass percentage of the first inorganic solid electrolyte particles with a particle size within the range of 0.01 to 0.3 μm is 25% to 50%; and the mass percentage of the second inorganic solid electrolyte particles with a particle size within the range of 0.3 to 0.6 μm is 50% to 75%. The particle size ratio of the second inorganic solid electrolyte particles to the first inorganic solid electrolyte particles is 1:0.03-0.4. The two-dimensional size of the two-dimensional layered powder is 0.6-2 μm; some of the inorganic solid electrolyte particles are embedded in the interlayers and / or the surface of the layers of the two-dimensional layered powder.

[0122] The 3D printing overhang slurry of this embodiment 2 is defined as a two-stage composite inorganic solid electrolyte particle.

[0123] In this Example 2, a slurry V with a specific composition is given. The difference between slurry V and slurry I is that the inorganic solid electrolyte particles only include first inorganic solid electrolyte particles with a particle size of 0.01 μm and a mass percentage of 40% and second inorganic solid electrolyte particles with a particle size of 0.3 μm and a mass percentage of 60%. The remaining raw materials, amounts and preparation methods are the same as those of slurry I.

[0124] Comparative Example 1

[0125] Slurry Comparison I of this Comparative Example 1 differs from Slurry I in Example 1 in that, during the preparation method, the inorganic solid electrolyte particles and the two-dimensional layered powder were mixed using mechanical stirring at a stirring speed of 500 rpm. The remaining raw materials, composition, and preparation method were the same as for Slurry I.

[0126] Comparative Example 2

[0127] The slurry of Comparative Example 1, Comparative II, differs from the slurry of Example 1 in that the surfactant is removed. The remaining raw materials, composition, and preparation method are the same as those of slurry I.

[0128] The rheological property curve of the slurry of comparative example 2 is as follows: Figure 4 As shown, it can be seen that the rheological properties of the slurry comparison II without adding surfactant are significantly worse than those of the slurry I of Example 1. This is because the surfactant can form a self-assembled lubricating layer on the surface of the inorganic solid electrolyte particles and the two-dimensional layered thermal conductive powder, reducing the friction between the particles and improving the rheological properties of the slurry.

[0129] Comparative Example 3

[0130] Slurry Comparison III of this Comparative Example 3 differs from Slurry I in Example 1 in that the raw materials do not contain two-dimensional layered powder, that is, the proportion of two-dimensional layered powder in the composite powder is 0. The remaining raw materials, composition, and preparation method are the same as those of Slurry I.

[0131] The rheological property curve of the slurry of comparative example 3 is compared with that of III. Figure 4 As shown in the figure, it can be seen that the slurry without the addition of two-dimensional materials has a higher viscosity and worse processing performance than that of Example III. The reason is that the slurry of Example 1 is a composite of two-dimensional materials and solid electrolyte particles with different particle sizes. Under shear force, the two-dimensional material acts as a lubricant, effectively reducing the movement resistance of the solid powder in the slurry. In addition, the solid electrolyte particles with different particle sizes allow small-sized solid electrolyte particles to flow in the gaps between large-sized solid electrolyte particles, weakening the flow resistance between particles, further reducing the slurry viscosity and improving the slurry rheological properties.

[0132] Comparative Example 4

[0133] Slurry Comparison IV of this Comparative Example 4 differs from Slurry Comparison III of Comparative Example 3 in that the inorganic solid electrolyte particles consist only of a single LATP oxide solid electrolyte group with a particle size of 0.5 μm. The remaining raw materials, composition, and preparation method are the same as those of Slurry Comparison III.

[0134] The rheological property curve of the slurry of comparative example 4 is compared with that of IV. Figure 4 As shown, it can be seen that the slurry without adding two-dimensional materials and without multi-particle compounding has a higher viscosity and worse processing performance than Example Ⅳ. The reason is that the slurry of Example 1 is compounded with two-dimensional materials and solid electrolyte particles with multi-particle size. Under shear force, the two-dimensional material acts as a lubricant, effectively reducing the movement resistance of the solid powder in the slurry. In addition, the multi-particle size solid electrolyte particles allow small-particle size solid electrolyte particles to flow in the gaps between large-particle size solid electrolyte particles, weakening the flow resistance between particles, further reducing the slurry viscosity and improving the slurry rheological properties.

[0135] Example 3

[0136] A positive electrode plate includes a hollow foil area, the hollow foil area is provided with an overhang packaging structure, and the overhang packaging structure is obtained by printing a 3D printing overhang slurry into the hollow foil area through a 3D printing method and then curing it.

[0137] In this Example 3, slurries I to V of Examples 1 and 2 were respectively used as 3D printing overhang slurries and printed onto a hollow foil area and then cured, thereby obtaining positive electrode sheets I to positive electrode sheets V. Simultaneously, slurries Comparative I to Comparative IV of Comparative Examples 1 to 4 were respectively used as 3D printing overhang slurries and printed onto a hollow foil area and then cured, thereby obtaining positive electrode sheets Comparative I to positive electrode sheets Comparative IV.

[0138] In this embodiment 3, for the subsequent solid-state battery assembly and battery performance testing, the following positive electrode sheet was specifically prepared.

[0139] The positive electrode sheet includes a positive electrode current collector (e.g., aluminum foil) and a positive electrode active material layer disposed on the positive electrode current collector. Specifically, the positive electrode slurry is applied to the positive electrode current collector and dried in a 70°C forced air oven for 2 hours, then moved to a 60°C vacuum oven for at least 6 hours. The dried electrode sheet is roll-pressed and then cut to the appropriate size, resulting in a semi-finished positive electrode sheet with a reserved foil area around the positive electrode active material layer. The sheet is then stored in a vacuum oven. The positive electrode slurry is obtained by uniformly dispersing a graft-modified polyvinylidene fluoride binder, Super P, LATP solid electrolyte, and NCM811 active material in an N-methylpyrrolidone solvent in a mass ratio of 1:1:10:88.

[0140] A 3D printing method is used to print the 3D printed overhang slurry onto the empty foil area of ​​the semi-finished positive electrode sheet. The printing width is 0.5 mm and the thickness is consistent with the thickness of the semi-finished positive electrode sheet. After drying and curing, a positive electrode sheet with an overhang packaging structure is obtained.

[0141] Example 4

[0142] The battery cell includes alternatingly stacked positive and negative electrode sheets, and a solid electrolyte layer is arranged between adjacent positive and negative electrode sheets; at least one side of the negative electrode sheet extends beyond the positive electrode sheet to form an overhang area; wherein a packaging structure is provided in the overhang gap area corresponding to the overhang area.

[0143] In this embodiment 4, the positive electrode sheets were respectively the positive electrode sheets I to V of embodiment 3, and correspondingly obtained battery cells I to V. At the same time, the positive electrode sheets comparison I to comparison IV were respectively used, and correspondingly obtained battery cells comparison I to comparison IV.

[0144] In this embodiment 4, for the subsequent solid-state battery assembly and battery performance testing, a lithium-indium alloy with a silver-carbon protective layer is selected as the negative electrode plate, and a Li6PS5Cl solid electrolyte membrane prepared with PTFE as a binder is selected as the solid electrolyte layer.

[0145] Example 5

[0146] Solid-state batteries, including battery cells.

[0147] In this embodiment 5, the cells are assembled into a solid-state battery, including isostatic pressing, tab welding, and final packaging. The isostatic pressing parameters in the assembly process are 500 MPa and 15 minutes, and the remaining assembly processes can be performed using conventional operations.

[0148] In this Example 5, the battery cells I to V of Example 4 were respectively assembled into solid-state batteries I to solid-state batteries V. At the same time, the battery cells Comparative I to Comparative IV were respectively assembled into solid-state batteries Comparative I to Solid-state batteries Comparative IV.

[0149] Comparative Example 5

[0150] This comparative example 5 is different from Example 5 in that the battery cell uses a laminated battery cell that is not overhang packaged, that is, the positive electrode plate uses the semi-finished positive electrode plate in Example 3, and a solid-state battery comparison V is obtained.

[0151] Performance testing:

[0152] 1. Test of rheological properties of 3D printing overhang slurry:

[0153] The rheological properties of the slurry were tested at room temperature using a rheometer with a 40 mm plate fixture, a test gap of 150 µm, and a shear rate sweep mode. Figure 4 Rheological properties curves of various slurries shown.

[0154] 2. The rheological properties of slurries I to V from Examples 1 and 2 and Comparative Slurries I to Comparative Slurries IV from Comparative Examples 1 to 4 were tested during actual 3D printing. Under the conditions of a 3D printing needle aperture of 100 μm, a constant extrusion pressure of 0.3 MPa, a straight path planning, an 80 μm line width, a 20 μm layer height, and a printing speed of 25 mm / s, the continuous printing time without needle clogging and the number of needle clogging events within 10 hours for slurries I to V and Comparative Slurries I to Comparative Slurries IV were tested. The test results are shown in Table 2.

[0155] Table 2

[0156]

[0157] As can be seen from Table 2, slurries I to V have longer continuous printing times and fewer clogging times within 10 hours compared to slurry comparison I to slurry comparison IV, indicating that the rheological properties of the slurry can be significantly improved by combining two-dimensional layered materials with multi-particle-size composite inorganic solid electrolytes and adding a self-assembled lubricating layer formed by a surfactant on the powder surface, thereby enhancing the feasibility and printing efficiency of 3D printing.

[0158] 3. Solid-state battery performance test:

[0159] The solid-state batteries I to V of Example 5, and the solid-state battery comparisons I to IV were tested for initial short-circuit rate and cycle performance, respectively.

[0160] The short-circuit rate was tested using a multimeter. The test results are shown in Table 3. Compared with Comparative Example 5 without an Overhang design, the short-circuit rate of the solid-state batteries corresponding to Examples 1-5 and Comparative Examples 1-4 with an Overhang design was significantly reduced. In addition, the short-circuit rate of the solid-state batteries of Examples 1-5, which were prepared using 3D-printed Overhang slurries containing two-dimensional materials and solid electrolyte particles of different sizes, was 0%. This indicates that the Overhang prepared by the 3D-printed Overhang slurry of this application can significantly alleviate the short-circuit problem in solid-state batteries and improve the yield and safety of solid-state batteries.

[0161] Table 3

[0162]

[0163] Cycling performance testing was performed using a charge-discharge test cabinet. The molded battery was assembled and tested with a voltage range of 2.8V to 4.3V and a charge-discharge current of 0.1C. Data such as the battery's charge and discharge capacity in grams was recorded. The test results are shown in Table 4.

[0164] Table 4

[0165]

[0166] It can be seen from the data in Table 4 that, compared with solid-state battery comparison I to solid-state battery comparison V, the capacity retention rate of solid-state batteries I to solid-state battery V after 100 cycles is significantly higher, and the short-circuit rate is relatively lower, indicating that the Overhang design of this application has a beneficial effect on alleviating the short circuit of solid-state batteries and improving the cycle performance of batteries. Solid-state batteries I to solid-state batteries V all use 3D printed Overhang slurry composed of two-dimensional materials and multi-particle-size solid electrolyte particles, which has more excellent rheological properties and better 3D printing processing performance. The obtained Overhang has higher density and strength, and is more capable of suppressing edge curling and lithium dendrites. In addition, the synergistic effect of two-dimensional materials and solid electrolyte particles after high-energy ball milling can construct a continuous lithium ion transmission path in the Overhang, uniformly depositing lithium ions at the edge of the negative electrode, which is beneficial to suppressing the growth of lithium dendrites and further improving the cycle life and safety of the battery.

[0167] In the embodiment of the present disclosure, for the inorganic solid electrolyte particles, when the endpoint values ​​of the particle size ranges of the first inorganic solid electrolyte particles, the second inorganic solid electrolyte particles and the third inorganic solid electrolyte particles overlap, the default may be the particle size that does not include the maximum endpoint value of the particle size range, or the particle size that does not include the minimum endpoint value of the particle size range, so as to avoid overlapping particle size values.

[0168] The above description and the accompanying drawings sufficiently illustrate the embodiments of the present disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, process and other changes. The embodiments represent only possible variations. Unless expressly required, individual components and functions are optional, and the order of operations may vary. Portions and features of some embodiments may be included in or replace portions and features of other embodiments. Moreover, the terms used in this application are only used to describe the embodiments and are not used to limit the claims. As used in the description of the embodiments and claims, the singular forms "a", "an" and "the" are intended to also include the plural forms unless the context clearly indicates otherwise. Similarly, the term "and / or" as used in this application means any and all possible combinations of one or more of the associated listings. In addition, when used in this application, the term "comprise" and its variations "comprises" and / or comprising refer to the presence of stated features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or groups thereof. In the absence of further restrictions, an element defined by the sentence "comprising a..." does not exclude the presence of other identical elements in the process, method or device that includes the element. In this article, each embodiment may focus on the differences from other embodiments, and the same and similar parts between the various embodiments can be referenced to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method part disclosed in the embodiments, then the relevant parts can be referred to the description of the method part.

[0169] Those skilled in the art will appreciate that the units and steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software may depend on the specific application and design constraints of the technical solution. The technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the embodiments of the present disclosure. The technicians will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0170] The flowcharts and block diagrams in the accompanying drawings show the possible implementation architectures, functions and operations of the systems, methods and computer program products according to the embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram can represent a module, program segment or part of the code, and the module, program segment or part of the code contains one or more executable instructions for implementing the specified logical functions. In some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different boxes can 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 consecutive operations or steps can actually be executed substantially in parallel, or they can sometimes be executed in the opposite order, which can depend on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, may be implemented by a dedicated hardware-based system that performs the specified function or action, or may be implemented by a combination of dedicated hardware and computer instructions.

Claims

1. A 3D printing overhang slurry, characterized in that: include: Composite powder, binder, surfactant and solvent, the mass ratio of the composite powder to the binder is 4 to 20:1, the mass ratio of the surfactant to the binder is 0.0005 to 0.02:1, and the solid content of the overhang slurry is 60% to 75%; wherein the composite powder includes inorganic solid electrolyte particles and two-dimensional layered powder, wherein the mass ratio of the inorganic solid electrolyte particles to the two-dimensional layered powder is 0.5 to 1.5:1, the particle size distribution range of the inorganic solid electrolyte particles is 0.01 to 2 μm, wherein the mass percentage of the first inorganic solid electrolyte particles with a particle size in the range of 0.01 to 0.3 μm is 25% to 50%; the two-dimensional size of the two-dimensional layered powder is 0.6 to 2 μm; some inorganic solid electrolyte particles are embedded in the interlayer and / or lamella surface of the two-dimensional layered powder; the two-dimensional layered powder includes a two-dimensional powder with a certain thickness composed of multiple lamellae, and there is a certain lamellae spacing between adjacent lamellae; The viscosity of 3D printing overhang slurry is 2-10 Pa·s -1 ; The 3D printed overhang slurry is used to be set in the overhang gap area corresponding to the overhang area of ​​the negative electrode plate of the battery cell.

2. The 3D printing overhang slurry according to claim 1, characterized in that: Among the inorganic solid electrolyte particles, the mass percentage of the second inorganic solid electrolyte particles having a particle size in the range of 0.3 to 0.6 μm is 40% to 75%; and / or Among the inorganic solid electrolyte particles, the mass percentage of the third inorganic solid electrolyte particles having a particle size in the range of 0.6 to 2 μm is 0% to 20%; When the mass percentage of the third inorganic solid electrolyte particles is not 0, the inorganic solid electrolyte particles include 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 percentages is 100%.

3. The 3D printing overhang slurry according to claim 2, wherein: The particle size ratio of the second inorganic solid electrolyte particles having a particle size in the range of 0.3 to 0.6 μm to the first inorganic solid electrolyte particles is 1:0.03 to 0.4; and / or The particle size ratio of the third inorganic solid electrolyte particles having a particle size in the range of 0.6 to 2 μm to the second inorganic solid electrolyte particles having a particle size in the range of 0.3 to 0.6 μm is 1:0.25 to 0.6; and / or The mass ratio of the second inorganic solid electrolyte particles having a particle size within the range of 0.3 to 0.6 μm to the first inorganic solid electrolyte particles is 4 to 7:3 to 6; and / or The mass ratio of the third inorganic solid electrolyte particles with a particle size in the range of 0.6 to 2 μm, the second inorganic solid electrolyte particles with a particle size in the range of 0.3 to 0.6 μm, and the first inorganic solid electrolyte particles is 0 to 2:4 to 7:3 to 6; and the third inorganic solid electrolyte particles are not 0.

4. The 3D printing overhang slurry according to claim 1, characterized in that: The inorganic solid electrolyte particles include one or more of oxide solid electrolyte particles, halide solid electrolyte particles, sulfide solid electrolyte particles, hydride solid electrolyte particles and nitride solid electrolyte particles; and / or, The two-dimensional layered powder includes a two-dimensional layered thermally conductive powder; and / or The two-dimensional layered powder includes 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 powder includes 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 framework; and / or The binder includes one or more of polyvinylidene fluoride, nitrile rubber, butadiene rubber, styrene-butadiene rubber, polypropylene carbonate, poly-tert-butyl acrylate, polyethylene glycol diacrylate, polyethylene oxide, polyethylene methacrylate, polymethyl methacrylate, polyethylene glycol diacrylate, polyacrylonitrile, polyisobutylene, polyethylene vinyl acetate and derivatives thereof; and / or The solvent includes one or more of N,N-dimethylacetamide, N-methylpyrrolidone, acetonitrile, toluene, xylene, butyl butyrate, butyl isobutyrate, ethyl acetate, chloroform, tetrahydrofuran and alkanes; and / or The surfactant includes one or more of linear alkyl primary mercaptan, polyethylene glycol octylphenyl ether, polysorbate-20, sorbitan monooleate, oleic acid, stearic acid, and hydroxyl functionalized alkyl ammonium salt.

5. The 3D printing overhang slurry according to any one of claims 1 to 4, characterized in that: Also includes: Lithium salt; the mass ratio of lithium salt to binder is 0.05-0.15:

1.

6. The 3D printing overhang slurry according to claim 5, characterized in that: The mass ratio of lithium salt to binder is 0.08 to 0.12:1; or the mass ratio of lithium salt to binder is 0.1:1; and / or The lithium salt includes one or more of lithium bis(trifluoromethylsulfonyl)imide, lithium bis(fluorosulfonyl)imide, lithium hexafluorophosphate, lithium tetrafluoroborate, lithium oxalatodifluoroborate, lithium bis(oxalatoborate), and lithium trifluoromethylsulfonate.

7. The 3D printing overhang slurry according to any one of claims 1 to 4, characterized in that: The mass ratio of the composite powder to the binder is 4 to 18:1; or, the mass ratio of the composite powder to the binder is 5 to 15:1; or, the mass ratio of the composite powder to the binder is 8 to 12:1; or, the mass ratio of the composite powder to the binder is 9 to 10:1; and / or The mass ratio of the surfactant to the binder is 0.001 to 0.02:1; or, the mass ratio of the surfactant to the binder is 0.005 to 0.02:1; or, the mass ratio of the surfactant to the binder is 0.01 to 0.02:

1.

8. The method for preparing a 3D printing overhang slurry according to any one of claims 1 to 7, wherein: include: According to the 3D printing overhang slurry according to any one of claims 1 to 7, preparing various raw materials; The inorganic solid electrolyte particles and the two-dimensional layered powder are mixed by ball milling to obtain a composite powder; The composite powder is mixed with other raw materials to obtain 3D printing overhang slurry.

9. The preparation method according to claim 8, characterized in that The ball milling parameters include: a ball-to-material ratio of 10 to 40:1; and / or a rotation speed of 400 to 600 rpm; and / or a ball milling time of 1 to 2 hours.

10. An electrode plate, characterized in that: The electrode plate is a positive electrode plate or a negative electrode plate; When the electrode plate is a positive electrode plate, the positive electrode plate includes a hollow foil area, the hollow foil area is an area corresponding to the overhang area of ​​the negative electrode plate, and the hollow foil area is provided with 3D printed overhang slurry; When the electrode plate is a negative electrode plate, the negative electrode plate includes an overhang area, and the overhang area of ​​the negative electrode plate is provided with a 3D printed overhang slurry; The electrode plate is a negative electrode plate, and the negative electrode plate is a combined negative electrode plate having solid electrolyte layers disposed on both sides thereof, and a 3D printed overhang slurry is disposed on a surface of the solid electrolyte layer of the combined negative electrode plate corresponding to an overhang area of ​​the negative electrode plate; The 3D printing overhang slurry is the 3D printing overhang slurry according to any one of claims 1 to 7 or the 3D printing overhang slurry prepared by the preparation method of the 3D printing overhang slurry according to any one of claims 8 to 9.

11. A battery cell, characterized in that: The device comprises alternating stacked positive and negative electrode sheets, with a solid electrolyte layer disposed between adjacent positive and negative electrode sheets; the negative electrode sheet extends beyond the positive electrode sheet on at least one side in a circumferential direction to form an overhang region; and a packaging structure is disposed in the overhanging gap region corresponding to the overhang region; Wherein, the packaging structure is obtained by setting a 3D printing overhang slurry in the overhang gap area; the 3D printing overhang slurry is the 3D printing overhang slurry as described in any one of claims 1 to 7 or the 3D printing overhang slurry prepared by the preparation method of the 3D printing overhang slurry as described in any one of claims 8 to 9.

12. The battery cell according to claim 11, characterized in that The positive electrode sheet adopts the positive electrode sheet of the electrode sheet as claimed in claim 10; or, the negative electrode sheet adopts the negative electrode sheet of the electrode sheet as claimed in claim 10 or a combined negative electrode sheet.

13. The method for preparing a battery cell according to claim 11 or 12, wherein: include: Prepare a positive electrode sheet, a negative electrode sheet, and a solid electrolyte layer; wherein the size of the negative electrode sheet is larger than that of the positive electrode sheet on at least one circumferential side, so that the negative electrode sheet has an overhang area; wherein the positive electrode sheet is the positive electrode sheet according to claim 10, or the negative electrode sheet is the negative electrode sheet according to claim 10, or a combination of negative electrode sheets; Alternately stacking positive electrode sheets and negative electrode sheets, and providing a solid electrolyte layer between adjacent positive electrode sheets and negative electrode sheets, to obtain a battery cell; Among them, the overhang gap area of ​​the battery cell is provided with a cured 3D printed overhang slurry.

14. The method for preparing a battery cell according to claim 13, wherein: Before alternately stacking the positive electrode sheets and the negative electrode sheets, the method further includes: curing the 3D printed overhang slurry provided on the positive electrode sheets or the negative electrode sheets to obtain the positive electrode sheets or the negative electrode sheets having an encapsulation structure; or After the positive pole pieces and the negative pole pieces are alternately stacked, the method further includes: curing the stacked battery cell structure to obtain a battery cell with a packaging structure.

15. A solid-state battery, characterized in that: include: The electrode plate according to claim 10; or the battery cell according to claim 11 or 12; or the battery cell prepared by the method for preparing the battery cell according to claim 13 or 14.

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