Preparation method of electrode sheet, positive electrode sheet, battery cell and solid-state battery, and overhang slurry

Abstract

The present application relates to the field of solid-state battery technology and discloses a method for preparing an electrode plate, a positive electrode plate, a battery cell, a solid-state battery, and an overhang slurry. The method for preparing the electrode plate comprises intermittently coating an electrode active slurry on an electrode current collector to obtain a first plate structure, wherein the first plate structure has an electrode active material layer and a hollow foil area surrounding the electrode active material layer; printing the overhang slurry on the hollow foil area of ​​the first plate structure by a 3D printing method to form a support structure to obtain an electrode plate; wherein the support structure is used to support the overhang area. The present application adopts a combination of intermittent coating and 3D printing to prepare the electrode plate, which can effectively prevent short circuits caused by pressurization during battery assembly and use, improve the safety performance of the solid-state battery, and increase the battery yield.

Description

Technical Field

[0001] The present application relates to the field of solid-state battery technology, for example, to a method for preparing an electrode pole piece, a positive electrode pole piece, a battery cell and a solid-state battery, and an overhang slurry. Background Art

[0002] As the global energy landscape shifts toward green, low-carbon, clean, efficient, intelligent, and diversified, high-energy-density energy storage devices have become key to achieving renewable energy consumption and promoting the electrification of terminal applications. All-solid-state lithium batteries, as the next-generation mainstream high-energy-density technology solution, have received widespread attention in the industry. All-solid-state batteries use solid electrolytes instead of liquid electrolytes, providing better thermal stability and lower internal resistance, thereby effectively reducing the safety risks of batteries under high-temperature conditions and enhancing battery reliability. Current solid-state batteries use traditional liquid batteries with overhanging negative electrodes. During pressurized assembly testing, due to the different sizes of the positive and negative electrodes and uneven force, the edges of the electrodes and solid electrolytes are easily deformed, which may seriously cause a short circuit inside the battery, greatly affecting the safety of the solid-state battery.

[0003] Currently, in order to solve the problem that the negative electrode overhang area is prone to collapse during the solid-state battery assembly process, resulting in contact between the positive and negative electrodes and then causing a battery short circuit, most of the methods are to stack the electrode sheets together first, and then fill the gaps corresponding to the negative electrode overhang area with supporting slurry to form a supporting structure to avoid the collapse of the negative electrode overhang area during the solid-state battery assembly process.

[0004] However, in the actual research and development process, the electrode plates are first stacked and then the supporting slurry is filled into the gaps corresponding to the overhang area. It is impossible to intuitively observe the degree of fit between the supporting structure and the electrode plates and the final shape of the supporting structure. This makes it difficult to accurately control the quality of the electrode plates, affecting the yield of the electrode plates.

[0005] 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

[0006] 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.

[0007] The embodiments of the present disclosure provide a method for preparing an electrode plate, a positive electrode plate, a battery cell, a solid-state battery, and an overhang slurry to solve the problem of electrode plate edge collapse and short circuit caused by uneven force at the overhang in solid-state batteries, and to ensure the formation area and final shape of the support structure, thereby reducing the yield rate of the electrode plate.

[0008] In some embodiments, a method for preparing an electrode plate includes: intermittently coating an electrode active slurry on an electrode current collector to obtain a first plate structure, wherein the first plate structure has an electrode active material layer and an empty foil area around the electrode active material layer; printing an overhang slurry on the empty foil area of ​​the first plate structure by a 3D printing method to form a support structure to obtain an electrode plate; wherein the support structure is used to support the overhang area.

[0009] In some embodiments, an overhang slurry is used as an overhang slurry in the method for preparing an electrode plate as described in any of the above embodiments, the overhang slurry includes a polymer base, an insulating inorganic filler and a solvent, the solid content of the overhang slurry is 50% to 80%, and the mass ratio of the polymer base and the insulating inorganic filler is (70 to 90): (10 to 30); or, the overhang slurry includes a hot-melt material.

[0010] In some embodiments, a positive electrode plate is prepared using the method for preparing an electrode plate as described in any one of the above embodiments, or the support structure of the positive electrode plate is prepared using the overhang slurry described in any one of the above embodiments.

[0011] In some embodiments, a 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, and the battery cell is provided with a hanging gap area corresponding to the overhang area, and the support structure is located in the hanging gap area; wherein the positive electrode sheet adopts the positive electrode sheet as described in any one of the above embodiments.

[0012] In some embodiments, the solid-state battery includes: the aforementioned battery cell.

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

[0014] In the preparation method of the electrode pole piece of the embodiment of the present disclosure, the electrode pole piece is prepared by combining intermittent coating and 3D printing. The electrode active slurry is coated on the electrode current collector by intermittent coating, and intermittent coating realizes the precise coating of the electrode active material and reduces the loss of the electrode active slurry. Then, a support structure is precisely constructed on the empty foil area of ​​the electrode pole piece by 3D printing, which effectively solves the edge thinning effect produced during the coating process, reduces the reservation of the empty foil area during coating, improves the utilization rate of the electrode current collector, and reduces production costs. The support structure is first constructed on the electrode pole piece by 3D printing before the electrode pole pieces are stacked, so that the size, shape and fit of the support structure with the electrode active material layer can be precisely controlled, which can effectively prevent short circuits caused by pressurization of the battery during assembly and use, improve the safety performance of the solid-state battery, and improve the battery yield.

[0015] 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

[0016] 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,

[0017] Figure 1 This is a schematic structural diagram of an electrode plate provided by an embodiment of the present disclosure from one perspective;

[0018] Figure 2 This is a structural schematic diagram of an electrode plate provided by an embodiment of the present disclosure from another perspective;

[0019] Figure 3 Schematic diagram of the structure of multiple electrode active material layers after intermittent coating of the electrode current collector provided by an embodiment of the present disclosure;

[0020] Figure 4 This is a schematic diagram of another electrode plate structure provided by an embodiment of the present disclosure;

[0021] Figure 5 This is a schematic flow chart of a method for preparing an electrode sheet provided by an embodiment of the present disclosure;

[0022] Figure 6 This is a schematic flow chart of another method for preparing an electrode sheet provided by an embodiment of the present disclosure;

[0023] Figure 7 It is a flow chart of another method for preparing an electrode plate provided in an embodiment of the present disclosure.

[0024] Reference numerals:

[0025] 10. Positive electrode current collector; 11. Positive electrode sheet; 111. Support structure; 112. Positive electrode active material layer; 113. Tab. DETAILED DESCRIPTION

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] Unless otherwise stated, the term "plurality" means two or more.

[0031] 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.

[0032] 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.

[0033] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present disclosure can be combined with each other.

[0034] Combine Figure 5 As shown, the embodiment of the present disclosure provides a method for preparing an electrode plate, comprising the following steps:

[0035] S110 , intermittently coating the electrode active slurry on the electrode current collector to obtain a first electrode sheet structure, wherein the first electrode sheet structure has an electrode active material layer and a hollow foil area around the electrode active material layer.

[0036] S120. Print overhang slurry on the empty foil area of ​​the first electrode structure using a 3D printing method to form a support structure to obtain an electrode electrode; wherein the support structure is used to support the overhang area.

[0037] In the disclosed embodiment, the electrode pole piece is prepared by combining intermittent coating of electrode active slurry with 3D printing support structure. The intermittent coating method realizes the precise regional coating of the electrode active material layer, reduces the waste of electrode active slurry and retains the empty foil area to facilitate the subsequent setting of the support structure. In the empty foil area, the support structure is constructed by 3D printing overhang slurry to obtain the electrode pole piece, which realizes effective support for the overhang area of ​​the electrode pole piece, improves the structural stability of the electrode pole piece, avoids deformation and poor contact of the pole piece due to lack of support in the overhang area during subsequent use, and is beneficial to improving the overall performance and safety of the battery. The support structure is directly constructed by 3D printing method in the empty foil area of ​​the electrode pole piece, so that the support structure can fit on the edge of the electrode active material, and the shape and size of the support structure are controllable, thereby improving the utilization rate of the electrode current collector and the yield rate of the solid-state battery.

[0038] In some optional embodiments, step S110 includes: intermittently coating the electrode active slurry on a coating area on the electrode current collector to obtain an electrode current collector having multiple electrode active material layers, wherein the multiple electrode active material layers are spaced apart. Drying and rolling the electrode current collector having multiple electrode active material layers, and die-cutting along the gap between two adjacent electrode active material layers, with a blank foil area reserved around each electrode active material layer, to obtain multiple first electrode sheet structures.

[0039] In the embodiment of the present disclosure, an interval coating technology is used to form a plurality of interval-arranged electrode active material layers on the electrode current collector, and the electrode current collector after intermittent coating is dried and rolled, thereby improving the setting stability of the electrode active material layer. The electrode current collector is then die-cut along the gap between adjacent electrode active material layers and an empty foil area is retained around each electrode active material layer. The empty foil area of ​​each electrode active material layer is then printed with overhang slurry using 3D printing technology to form a support structure. This ensures the uniformity and consistency of the distribution of the electrode active material layer of each first electrode sheet structure, and the size of the empty foil area of ​​each electrode active material layer, thereby ensuring the size and shape of the support structure, and also facilitates the printing of the support structure, thereby improving the stability and controllability of the electrode sheet preparation process.

[0040] Optionally, the distance between two adjacent electrode active material layers is greater than or equal to 3 mm, so that the gap between the two adjacent electrode active material layers is large enough to ensure the width of the empty foil area corresponding to the two adjacent electrode active material layers, thereby ensuring the width of the support structure.

[0041] Optionally, step S120 includes: printing an overhang slurry onto the empty foil area of ​​each first electrode structure using a 3D printing method to obtain a printed first electrode structure; drying or curing the printed first electrode structure to obtain a first electrode structure having a support structure; and rolling the first electrode structure having the support structure to obtain an electrode electrode.

[0042] In the disclosed embodiment, an overhang slurry is placed in the empty foil area of ​​each first electrode structure by 3D printing and then cured or dried. This allows the overhang slurry to quickly and stably form a support structure. The electrode electrode formed with the support structure is then rolled to make the thickness of the electrode electrode uniform and flat. This also allows the support structure to be tightly combined with the electrode current collector and the electrode active material layer, ultimately preparing the electrode electrode. This enhances the overall strength and reliability of the electrode electrode, ensuring that the support structure can continue to effectively play a supporting role during subsequent use. At the same time, the cured or dried support structure can meet the requirements of different processes and usage environments. The rolling process helps to improve the physical properties of the electrode, such as compaction density.

[0043] like Figure 6 As shown, the embodiment of the present disclosure also provides a method for preparing an electrode plate, comprising the following steps:

[0044] S111. Intermittently coating the electrode active slurry on the coating area on the electrode current collector to obtain an electrode current collector having a plurality of electrode active material layers, wherein the plurality of electrode active material layers are arranged at intervals.

[0045] S112 , drying and rolling the electrode current collector having multiple electrode active material layers, performing die-cutting along the gaps between adjacent electrode active material layers, and reserving an empty foil area around each electrode active material layer to obtain multiple first electrode sheet structures.

[0046] S121. Print overhang slurry on the empty foil area of ​​each first pole piece structure by a 3D printing method to obtain a printed first pole piece structure.

[0047] S122, drying or curing the printed first electrode structure to obtain a first electrode structure with a support structure;

[0048] S123 , rolling the first pole piece structure with the support structure to obtain an electrode pole piece.

[0049] In other optional embodiments, step S110 includes: intermittently coating the electrode active slurry on the coating area on the electrode current collector to obtain a first electrode sheet structure having multiple electrode active material layers; wherein the first electrode sheet structure includes multiple spaced electrode active material layers and empty foil areas arranged between adjacent electrode active material layers.

[0050] In the disclosed embodiment, the first electrode sheet structure includes multiple electrode active material layers and multiple empty foil areas, which facilitates the subsequent printing of multiple support structures on the same electrode current collector, thereby improving the preparation efficiency of the electrode sheet.

[0051] Optionally, step S120 includes: printing an overhang slurry on an empty foil area of ​​the first electrode structure by a 3D printing method to obtain a second electrode structure; curing or drying the second electrode structure to form a second electrode structure with a support structure; rolling the second electrode structure with the support structure, and die-cutting along the printing area to obtain a plurality of electrode plates; wherein the printing area is located on the outside of the electrode active material layer, and a support structure is left around the electrode active material layer of each electrode plate.

[0052] In the disclosed embodiment, a support structure is first formed in the empty foil area of ​​the first electrode structure by 3D printing to obtain a second electrode structure. After solidification or drying and rolling, die-cutting is performed along the printed area on the outside of the electrode active material layer to obtain multiple electrode plates. A support structure is left around the electrode active material layer of each electrode plate. This enables the simultaneous production of multiple electrode plates, improves production efficiency, and the support structure of each plate is uniform, ensuring the consistency of battery quality, which is conducive to large-scale production. At the same time, the presence of the support structure improves the stability and reliability of the electrode plates, and helps to extend the service life of the battery. In addition, the printing of the support structure is more accurate, which can avoid the situation where the support structure strength is insufficient due to insufficient space in the empty foil area, and can also avoid waste caused by excessive size of the empty foil area.

[0053] In some embodiments, a second pole piece structure is obtained by printing an overhang slurry in an empty foil area of ​​a first pole piece structure through a 3D printing method, including: when the printing area is an empty foil area, setting the overhang slurry in all the printing areas of the first pole piece structure through a 3D printing method to obtain the second pole piece structure.

[0054] In the disclosed embodiment, the first electrode sheet structure has multiple electrode active material layers spaced apart, so that multiple printing areas are formed between adjacent electrode active material layers and on the outer edges of the electrode active material layers. When the printing areas are all empty foil areas, the entire printing area is printed with overhang slurry, thereby achieving complete filling of the printing area of ​​the first electrode sheet structure, and the support structure can form a continuous and complete structural system in the printing area, effectively increasing the support stability and support strength of the support structure. In addition, this "full coating" method does not require reserving blank areas in the printing area, further improving the preparation efficiency of the electrode sheet.

[0055] Optionally, when the printed area is a blank foil area, die-cutting is performed along the printed area, including: die-cutting along the blank foil area. Here, when the printed area is fully coated with overhang slurry, die-cutting is performed on the printed area, that is, die-cutting is performed in the blank foil area, so that the support structures between adjacent electrode active material layers are cut, so that each electrode active material layer is provided with a corresponding support structure.

[0056] In other optional embodiments, the printing area includes a blank foil area and a cutting area, and the cutting area is located on the side of the blank foil area away from the electrode active material layer corresponding to the blank foil area, and no overhang slurry is provided in the cutting area. In this way, the printing area between adjacent electrode active material layers includes both a blank foil area and a cutting area, and the overhang slurry is only printed on the blank foil area, while the overhang slurry is not provided in the cutting area. This facilitates die-cutting in the cutting area and improves die-cutting accuracy.

[0057] Optionally, in the case that the printing area includes a cutting area and a blank foil area, die-cutting is performed along the printing area, including: die-cutting along the cutting area.

[0058] like Figure 7 As shown, the embodiment of the present disclosure also provides another method for preparing an electrode plate, comprising the following steps:

[0059] S211. Intermittently apply the electrode active slurry to the coating area on the electrode current collector to obtain a first electrode sheet structure having multiple electrode active material layers; wherein the first electrode sheet structure includes multiple electrode active material layers arranged at intervals and empty foil areas arranged between adjacent electrode active material layers.

[0060] S212, printing the overhang slurry on the empty foil area of ​​the first pole piece structure by a 3D printing method to obtain a second pole piece structure.

[0061] S213 , curing or drying the second pole piece structure to form a second pole piece structure with a support structure.

[0062] S214. Roll-press the second electrode sheet structure with the support structure, and die-cut along the printing area to obtain a plurality of electrode sheets; wherein the printing area is located outside the electrode active material layer, and a support structure is left around the electrode active material layer of each electrode sheet.

[0063] Optionally, the width of the empty foil area is 0.5 mm to 1 mm, that is, the width of the support structure is 0.5 mm to 1 mm, so as to ensure the strength of the support structure.

[0064] Optionally, the height of the support structure is 40 μm to 60 μm to ensure that the support structure can contact and support the overhang area. In practical applications, the height of the support structure is set according to the gap between the pole pieces.

[0065] Optionally, the distance between two adjacent electrode active material layers is greater than or equal to 3 mm, that is, when the electrode active slurry is intermittently coated on the electrode current collector, the distance between two adjacent electrode active layers is greater than or equal to 3 mm. The above-mentioned distance is adopted when any of the above-mentioned preparation methods is adopted, so that the width of the empty foil area can be ensured and sufficient space can be reserved for cutting.

[0066] Optionally, the length of any electrode active material layer is 80 mm to 100 mm, and the width of the electrode active material layer is 35 mm to 50 mm.

[0067] Optionally, the length of any electrode active material layer is 85 mm to 95 mm, and the width of the electrode active material layer is 40 mm to 50 mm.

[0068] Optionally, the length of any electrode active material layer is 92 mm, and the width of the electrode active material layer is 46 mm.

[0069] The embodiments of the present disclosure also provide an overhang slurry, which is used as the overhang slurry in the method for preparing the electrode plate described in any of the above embodiments. The overhang slurry includes a polymer base, an insulating inorganic filler, and a solvent. The solid content of the overhang slurry is 50% to 80%, and the mass ratio of the polymer base to the insulating inorganic filler is (70~90): (10~30).

[0070] In the disclosed embodiments, the overhang slurry utilizes a polymer substrate, an insulating inorganic filler, and a solvent. The polymer substrate provides a skeletal support and bonding function. The insulating inorganic filler primarily adjusts the mechanical properties of the support structure to achieve a certain mechanical strength, while the solvent is primarily used to form a uniformly dispersed and stable slurry, ensuring fluidity for the overhang slurry and facilitating 3D printing. The solids content of the polymer substrate is between 50% and 80%, which balances the solids content and rheological properties of the slurry, making the overhang slurry suitable for 3D printing methods. This ensures both printing strength and smoothness, enabling the desired support structure to be achieved in the overhang gaps, addressing the issue of edge collapse and short circuiting in solid-state batteries. The mass ratio of the polymer substrate to the insulating inorganic filler is (70-90):(10-30), which further ensures the strength of the support structure while also imparting a certain degree of elasticity and stress buffering.

[0071] Optionally, the polymer substrate includes a polymer adhesive that cures in situ to form a film. During the electrode plate fabrication process, the polymer adhesive that cures in situ can form an effective bond between the electrode active material layer and the support structure, and between the support structure and the current collector. Through in situ curing, the polymer substrate tightly bonds with the various components of the electrode plate, increasing the contact area and bonding strength, thereby effectively enhancing the stability of the entire electrode plate, preventing the support structure from falling off or shifting during use, and improving the reliability and safety of the battery.

[0072] Optionally, the overhang slurry includes a thermofusible material. The thermofusible material can improve the contact interface between the support structure and the electrode active material, thereby improving the performance of the battery.

[0073] Optionally, the hot-melt material may be a composite hot-melt material, such as a composite hot-melt material obtained by melting a mixture of thermoplastic polyurethane and flame-retardant phosphate ester.

[0074] Optionally, the polymer substrate includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyisobutylene, polyetheretherketone, styrene-butadiene rubber, polyethylene oxide, polyimide, polyacrylonitrile, sodium carboxymethyl cellulose, UV adhesive, photosensitive adhesive, and thermal crosslinking.

[0075] Optionally, the insulating inorganic filler includes one or more of aluminum oxide, boron nitride and silicon dioxide.

[0076] Optionally, the solvent includes one or more of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, isopropyl alcohol, toluene, xylene and dimethylformamide.

[0077] Optionally, the overhang slurry further comprises functional additives, wherein the functional additives include one or more of a toughening agent, a surfactant and a cross-linking agent.

[0078] In the disclosed embodiments, the toughening agent can improve the toughness of the overhang slurry after curing, so that it is not easy to break or damage when it is subjected to external impact or volume changes during battery charging and discharging, thereby enhancing the durability of the support structure. The surfactant helps to improve the rheological properties and wettability of the overhang slurry, so that the overhang slurry can be more evenly filled into the empty foil area during the 3D printing process, forming better contact with the electrode current collector and the electrode active material layer, and improving the bonding strength. The cross-linking agent can promote the cross-linking reaction between the molecular chains in the polymer substrate to form a more stable three-dimensional network structure, thereby improving the mechanical strength, thermal stability and chemical stability of the overhang slurry, so that the support structure can still maintain good performance under a variety of harsh conditions.

[0079] Optionally, the insulating inorganic filler includes a two-dimensional layered powder, and the overhang slurry also includes inorganic solid electrolyte particles, and 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 μm to 2 μm, of which the mass percentage of the first inorganic solid electrolyte particles with a particle size in the range of 0.01 μm to 0.3 μm is 25% to 50%; the two-dimensional size of the two-dimensional layered powder is 0.6 μm to 2 μm; some inorganic solid electrolyte particles are embedded in the interlayer and / or lamellar surface of the two-dimensional layered powder.

[0080] The overhang slurry of the embodiment of the present disclosure is a compound of inorganic solid electrolyte particles with a large particle size distribution range and a two-dimensional layered powder. Then, the inorganic solid electrolyte particles that are compatible with the interlayer spacing and lamellae surface defects of the two-dimensional layered powder can be embedded into the interlayer and / or lamellae surface of the two-dimensional layered powder. Then, the lamellae surface defects of the two-dimensional layered powder provide affinity sites for lithium ions, and the embedded inorganic solid electrolyte particles cooperate to 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 side, and achieving the expected effect of filling the overhang voids.

[0081] 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.

[0082] 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.

[0083] In some embodiments, 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 75% of the inorganic solid electrolyte particles. In this embodiment, the proportion of the second inorganic solid electrolyte particles with a particle size range of 0.3 to 0.6 μm is limited so that they are compounded with the first inorganic solid electrolyte particles in a smaller particle size range to further improve the rheological properties of the overhang slurry, construct a more optimal continuous ion transport path, and further increase the density and strength of the support structure.

[0084] 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.

[0085] 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.

[0086] 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.

[0087] 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 0.01μm to 0.6μm. 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%.

[0088] 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).

[0089] 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%.

[0090] 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%.

[0091] 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, etc. By limiting the first particle size ratio, the rheological properties of the overhang slurry are further improved, a more optimal continuous ion transport path is constructed, and the density and strength of the support structure are further increased.

[0092] 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 μm 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 μm 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.

[0093] 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%.

[0094] 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).

[0095] 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.

[0096] 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%.

[0097] 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%.

[0098] 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.

[0099] 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 support structure are further improved.

[0100] 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.

[0101] In the disclosed embodiment, the two-dimensional layered powder includes a two-dimensional powder having a certain thickness and composed of multiple sheets, with a certain inter-sheet spacing between adjacent sheets, and at least some of the first inorganic solid electrolyte particles with a particle size in the range of 0.01 μm to 0.3 μm can be embedded in the interlayers and / or sheet surfaces of the two-dimensional layered powder. In addition, the two-dimensional layered powder generally has surface defects on the two-dimensional sheet surface. These surface defects cooperate with the embedded inorganic solid electrolyte particles to 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 side, and achieving the expected effect of filling the overhang gap.

[0102] 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.

[0103] In some embodiments, the two-dimensional size of the two-dimensional layered powder is 0.8 μm to 2 μm. Alternatively, the two-dimensional size of the two-dimensional layered powder is 1 μm to 1.5 μm.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] 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.

[0108] Optionally, the two-dimensional layered nitride inorganic material includes hexagonal boron nitride, two-dimensional layered aluminum nitride or two-dimensional layered carbon nitride.

[0109] Optionally, the layered silicate material comprises montmorillonite.

[0110] Optionally, the layered sulfide includes molybdenum disulfide or tungsten disulfide.

[0111] 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.

[0112] In the overhang slurry of the embodiment of the present disclosure, the polymer base can bond the insulating inorganic filler and the inorganic solid electrolyte particles. By controlling the ratio of the insulating inorganic filler and the inorganic solid electrolyte particles to the polymer base, the overhang slurry can have rheological properties suitable for the 3D printing method, and can ensure the stability of the formed support structure as well as the heat dissipation and ion transmission functions.

[0113] In some embodiments, the overhang slurry of the disclosed embodiments further includes a lithium salt; the mass ratio of the lithium salt to the polymer substrate is 0.05 to 0.15:1. In this embodiment, lithium salt is added as a supplementary lithium source for the overhang support structure to provide sufficient lithium ions, and cooperates with the interface of the polymer substrate, 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 support structure.

[0114] Optionally, the mass ratio of the lithium salt to the polymer substrate is 0.08 to 0.12: 1. Optionally, the mass ratio of the lithium salt to the polymer substrate is 0.1:1.

[0115] 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.

[0116] In some embodiments, when the electrode plate is prepared by first 3D printing an overhang slurry and then die-cutting, the overhang slurry includes a polymer base, an insulating inorganic filler, a solvent, a cross-linking agent, a toughening agent, and a surfactant. This provides the overhang slurry with a certain toughness, allowing the support structure to withstand the shear force and stress during the die-cutting process, thereby preventing the stress generated during the die-cutting process from causing the support structure to fracture, thereby ensuring the stability and reliability of the support structure.

[0117] Optionally, the solid content of the overhang slurry is 60% to 75%, or the solid content of the overhang slurry is 65% to 75%, or the solid content of the overhang slurry is 60% to 70%.

[0118] In the disclosed embodiments, the solid content of the overhang slurry is within the above-mentioned range, achieving a balance between the rheological properties of the slurry and the high solid content, so that the overhang slurry has a reasonable number of solid phase particles and an appropriate particle spacing, thereby having reasonable 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 support structure. It is understandable that the solid content of the overhang slurry can be either mass solid content or volume solid content, without limitation.

[0119] Optionally, the solid content of the overhang slurry is the mass solid content. The solid content is adjusted by the amount of solvent added, that is, the amount of solvent used in the overhang slurry of the present disclosure is determined according to the solid content of the slurry. The type of solvent is not limited.

[0120] Optionally, the solids content of the overhang slurry is 60%, 65%, 68%, 69%, 70%, 71%, 73%, 74% or 75%, or any value within the range of 60% to 75%.

[0121] Optionally, the mass ratio of the polymer substrate, the insulating inorganic filler, the cross-linking agent, the toughening agent, and the surfactant is (40-60):(20-30):(5-15):(5-10):(1-3).

[0122] In the embodiments of the present disclosure, each raw material is within the above-mentioned range, and the polymer base can provide sufficient bonding force to tightly bond the overhang slurry to the electrode pole piece to ensure structural stability. The insulating inorganic filler can effectively improve the insulation of the overhang slurry and avoid the risk of battery short circuit. The proportion of the two is coordinated to achieve a balance between bonding and insulation performance, meeting the safety and stability requirements of the battery. The content of the toughening agent can significantly improve the toughness of the overhang slurry after curing, so that the support structure can withstand the mechanical stress and shear stress during battery use and die-cutting, and prevent the support structure from breaking. The cross-linking agent can promote polymer cross-linking to form a stable network, enhance mechanical strength and thermal stability, and make the support structure both strong and flexible. Although the proportion of surfactant is low, it can significantly improve the wettability and dispersibility of the overhang slurry, so that the overhang slurry can better fill the empty foil area during 3D printing, fit closely with the electrode current collector and electrode active material layer, improve the bonding strength, and at the same time make the surface of the support structure smoother and reduce defects. In summary, by setting the above raw materials and reasonably configuring the mass ratio, the strength of the support structure can be guaranteed, and the support structure can also have a certain elasticity and flexibility, which can not only relieve the stress generated when the battery is subjected to force, but also resist the shear force and stress generated during die-cutting, thereby avoiding the support structure from breaking.

[0123] Optionally, the polymer substrate includes one or more of polytetrafluoroethylene, polyimide, polyisobutylene and polyetheretherketone.

[0124] In the embodiments of the present disclosure, the above-mentioned polymer substrate has good chemical stability and thermal stability, as well as good flexibility and elasticity. It can also take into account high strength, high rigidity and high toughness, ensure the mechanical strength of the supporting structure, resist various external stresses, avoid breakage or damage, and ensure the stable operation of the battery.

[0125] Optionally, the solvent includes one or more of N-methylpyrrolidone, isopropyl alcohol, toluene, and xylene.

[0126] In the disclosed embodiments, the aforementioned solvent exhibits excellent solubility, effectively dispersing and dissolving the polymer substrate and other components, resulting in a slurry with uniform rheological properties, facilitating a smooth 3D printing process. It also possesses low surface tension and excellent wetting properties, facilitating uniform spreading and filling of the overhang slurry within the bare foil area. Furthermore, its rapid evaporation allows for rapid drying of the slurry, improving production efficiency.

[0127] Optionally, the crosslinking agent includes one or more of epoxy resin, polyurethane, acrylate, and silane crosslinking agent.

[0128] In the embodiment of the present disclosure, the above-mentioned cross-linking agent can form a highly cross-linked three-dimensional network structure after cross-linking, which significantly improves the mechanical strength and thermal stability of the overhang slurry, makes the support structure have higher hardness and rigidity, and can better resist external impact and high temperature influence. At the same time, it has good bonding properties and can enhance the bonding force between the support structure and the electrode material.

[0129] Optionally, the toughening agent includes one or more of polyurethane, polyethylene, polypropylene and ethylene-vinyl acetate copolymer.

[0130] In the embodiments of the present disclosure, the toughening agent has a unique molecular structure and has the characteristics of both hard segments and soft segments, which enables it to have excellent wear resistance and high elasticity, and can effectively improve the impact resistance and flexibility of the supporting structure, making it less likely to break when subjected to external force. At the same time, it has good compatibility with a variety of polymer substrates, can be evenly dispersed in the slurry, and exert a good toughening effect.

[0131] Optionally, the surfactant includes one or more of polyvinyl alcohol, sodium lauryl sulfate, sodium alkylbenzene sulfonate, polyoxyethylene alcohol ether and silane coupling agent.

[0132] In the embodiments of the present disclosure, the above-mentioned surfactant has good water solubility and film-forming properties, can improve the surface properties of the overhang slurry, reduce the surface tension of the overhang slurry, improve its wettability and spreadability on the empty foil area, enable the overhang slurry to be more evenly filled in the empty foil area, and enhance the surface properties of the support structure.

[0133] like Figures 1 to 4 As shown, the embodiment of the present disclosure further provides a positive electrode plate 11, which is prepared using the electrode plate preparation method as described in any one of the above embodiments, or the support structure 111 of the positive electrode material adopts the overhang slurry described in any one of the above embodiments.

[0134] The positive electrode plate 11 of the embodiment of the present disclosure includes the overhang slurry or electrode plate of any of the aforementioned embodiments. The battery cell has all the technical effects of the overhang slurry and electrode plate, which will not be repeated here.

[0135] An embodiment of the present disclosure provides a battery cell, which includes a laminate structure and a support structure 111. The laminate structure includes alternatingly stacked positive electrode sheets 11 and negative electrode sheets, and a solid electrolyte layer is arranged between adjacent positive electrode sheets 11 and negative electrode sheets; at least one side of the negative electrode sheet extends beyond the positive electrode sheet 11 in a circumferential direction to form an overhang area; wherein a support structure 111 is arranged in a hanging gap area corresponding to the overhang area; wherein the support structure 111 is obtained by arranging an overhang slurry on the positive electrode sheet 11; the overhang slurry is the overhang slurry of any of the aforementioned embodiments.

[0136] Alternatively, as Figures 1 to 4 As shown, the positive electrode sheet 11 includes a positive electrode current collector 10 and a positive electrode active material layer 112 disposed on the positive electrode current collector 10. The positive electrode active material layer 112 is covered on one side or both sides of the positive electrode current collector 10, depending on actual needs.

[0137] In this embodiment, the positive electrode current collector 10 is typically made of a metal material. Optionally, the material of the positive electrode current collector 10 includes aluminum foil. The thickness of the positive electrode current collector 10 can be controlled to be between 6 μm and 20 μm. Optionally, the thickness of the positive electrode current collector 10 is between 10 μm and 20 μm. Optionally, the positive electrode current collector 10 includes aluminum foil with a thickness of 10 μm to 20 μm.

[0138] Optionally, the positive electrode active material layer 112 includes a positive electrode active slurry, which is mainly composed of one or more complexes of lithium iron phosphate, lithium cobaltate, lithium manganese oxide, lithium vanadate, lithium nickelate, lithium manganese oxide, lithium nickel manganese oxide, lithium-rich manganese base, lithium iron manganese phosphate, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium vanadium phosphate, sulfur, lithium sulfide and sulfur iodide.

[0139] Optionally, the negative electrode plate includes a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector. The negative electrode active material layer includes a negative electrode active slurry, which is determined according to actual needs.

[0140] In this embodiment, the negative electrode current collector is typically made of a metal material. Optionally, the negative electrode current collector comprises copper foil. The thickness of the negative electrode current collector can be controlled to be between 6 μm and 10 μm. Optionally, the thickness of the negative electrode current collector is between 6 μm and 8 μm. Optionally, the negative electrode current collector comprises copper foil having a thickness of 6 μm to 10 μm.

[0141] Optionally, the negative electrode active material layer is not limited and is determined according to actual needs. Optionally, the negative electrode active material layer includes a negative electrode active material and other additives, and the other additives include one or more composites of components such as pure silicon material, graphite material, carbon material, silicon-carbon material, and silicon-oxygen material.

[0142] Optionally, a negative electrode plate includes a negative electrode active material layer. Specifically, the negative electrode plate of this embodiment consists solely of a negative electrode active material layer. The negative electrode active material layer is designed to reversibly accommodate and release lithium ions and function as an external conductor, eliminating the need for a negative electrode current collector to provide conductivity. In this case, the negative electrode active material layer is composed of a composite of one or more conductive materials, such as lithium metal and carbon materials.

[0143] Optionally, the negative electrode plate includes one or more of a lithium metal negative electrode, a lithium alloy negative electrode, a graphite negative electrode, a pure silicon negative electrode, a pure SiO negative electrode, a pure SiC negative electrode, a silicon-graphite mixed negative electrode, a SiO-graphite negative electrode, a SiC-graphite negative electrode, a silicon alloy negative electrode, a pure tin negative electrode and a tin alloy negative electrode.

[0144] In the battery cell of the disclosed embodiment, the solid electrolyte layer connects the negative electrode active material layer and the positive electrode active material layer 112 to each other, providing lithium ion transport. The solid electrolyte layer comprises a composite of one or more components selected from sulfide electrolytes, oxide electrolytes, polymer electrolytes, and halide electrolytes.

[0145] The embodiments of the present disclosure further provide a solid-state battery, comprising: the electrode plate of any of the aforementioned embodiments; or, the battery cell of any of the aforementioned embodiments.

[0146] The following specific examples are given to specifically illustrate the overhang slurry, electrode plate, battery cell and its preparation method and solid-state battery of the embodiments of the present disclosure, so as to more clearly illustrate the technical problems, technical solutions and beneficial effects solved by the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. 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.

[0147] 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.

[0148] Example 1:

[0149] A solid-state battery, the specific preparation method is as follows:

[0150] (1) Preparation of positive electrode sheet:

[0151] According to the weight ratio of nickel-based composite positive electrode material (Ni90): lithium chloride phosphosulfide solid electrolyte (LPSCl): vapor-grown carbon fiber (VGCF): styrene-ethylene-butylene-styrene block copolymer (SEBS) = 76:20:2:2, weigh the component materials, dissolve the binder SEBS in anisole solvent, and stir magnetically to obtain a 5wt% binder solution. Then, Ni90, LPSCl and conductive agent VGCF are mixed and dispersed in a ball mill for 30 minutes. The binder solution is mixed with the mixed materials after ball milling. The solvent anisole is calculated and added to prepare a 65wt% wet-process positive electrode slurry. The slurry is dispersed in a degassing machine for 2 hours. The obtained positive electrode active slurry is intermittently coated on the surface of the positive electrode current collector 10, as shown in FIG. Figure 3 As shown, a positive electrode active material layer 112 arranged in an array on the positive electrode current collector 10 is obtained. The size of the positive electrode active material layer 112 is 90*44mm, and the coating area interval, that is, the interval between two adjacent positive electrode active material layers 112 is 3mm. The positive electrode sheet 11 is obtained by vacuum drying at 80℃ for 3h to remove the solvent. When die-cutting, a blank foil area is left around the electrode active material layer. The blank foil area around the four sides is 1mm. The die-cut size is 92*46mm. When die-cutting, the tab 113 (as shown in FIG. 11) must also be left. Figure 4 shown).

[0152] (2) 3D printing support structure:

[0153] Polyvinylidene fluoride (PVDF) and aluminum oxide nanoparticles are added to N-methylpyrrolidone (NMP) in a mass ratio of (70-90): (10-30), placed in a magnetic stirrer and stirred for 4 hours to obtain an overhang slurry. Using a 3D printing device with micron-level precision, the overhang slurry is accurately printed on the four sides of the positive active material layer 112 of the positive electrode plate 11, that is, the empty foil area, by extrusion printing. The height of the printed support structure 111 is 50μm, the printing accuracy is controlled at ±5μm, and the printing speed is 5mm / s. The printed positive electrode plate 11 is placed in a vacuum oven at 120°C and dried for 4 hours to remove the solvent, and then roller pressed to make the thickness of the positive electrode plate 11 uniform and flat, to obtain a positive electrode plate 11 with a support structure 111 (such as Figure 1 and Figure 2 shown).

[0154] (3) Preparation of negative electrode sheet:

[0155] According to the weight ratio of micron silicon particles: polyvinylidene fluoride (PVDF): vapor-grown carbon fiber (VGCF) = 92:5:3, the components were weighed, PVDF was dissolved in NMP, and a 7wt% binder solution was prepared. The micron silicon and VGCF were ball-milled for 30 minutes. The binder glue was added to the mixed powder to prepare a 68wt% negative electrode slurry. The slurry was homogenized and dispersed in a degassing machine for 3 hours to obtain the negative electrode active slurry. The obtained negative electrode active slurry was applied to the negative electrode current collector, and the negative electrode sheet was dried in a vacuum oven at 85℃ for 3 hours to remove the solvent. After drying, the negative electrode sheet was roller-cut to obtain the negative electrode sheet. The die-cut size was 92*46mm, and the tabs needed to be left during die-cutting.

[0156] (4) Preparation of solid electrolyte layer:

[0157] The components of lithium phosphosulfide chloride solid electrolyte (LPSCl) and styrene-ethylene-butylene-styrene block copolymer (SEBS) were weighed in a 98:2 weight ratio. 5wt% of SEBS was dissolved in anisole solvent and magnetically stirred for 30 minutes to prepare a glue solution. Electrolyte powders were then added to the glue solution according to the weight ratio and dispersed in a degassing machine for 1 hour to prepare an electrolyte slurry. The electrolyte slurry was then coated on a 15µm stainless steel foil using a 100µm scraper and baked in a vacuum oven at 80°C to evaporate the solvent, resulting in an electrolyte membrane. The resulting solid electrolyte layer was then cut into 92x46mm squares.

[0158] (5) Battery assembly and testing:

[0159] The positive electrode sheet with a supporting structure, the solid electrolyte layer, and the negative electrode sheet are assembled together through a stacking process to form a solid-state battery cell; then the tabs are welded, vacuum packaged, and isostatically pressed at 500 MPa for 8 minutes to obtain a soft-pack battery, and charge and discharge tests are carried out under a pressure of 50 MPa.

[0160] Example 2:

[0161] The difference from Example 1 is that in step (2), the overhang slurry uses a hot-melt material. The remaining steps are the same. Step (2) is specifically as follows:

[0162] (2) 3D printing overhang support structure:

[0163] A composite hot-melt material, obtained by melting a mixture of thermoplastic polyurethane (TPU) and flame-retardant phosphate, is used as the overhang slurry. Using a hot-melt extrusion printer, the overhang slurry is precisely printed around the positive active material layer of the positive electrode plate, forming a support structure. The support structure has a height of 50μm, with a printing accuracy of ±5μm, a printing speed of 5mm / s, and a printing nozzle diameter of 20μm. After printing, the printed area is rapidly cooled by a directional cold air flow, solidifying the hot-melt material into shape. Subsequently, a roller pressing process is performed to ensure a uniform and flat electrode thickness, resulting in a positive electrode plate with a support structure.

[0164] Example 3:

[0165] The difference from Example 1 is that in step (1), the positive electrode active slurry is intermittently coated and then not die-cut. In step (2), the overhang slurry uses improved materials and components, and the overhang structure is printed before die-cutting. The remaining steps are the same. Steps (1) and (2) are specifically as follows:

[0166] (1) Preparation of positive electrode sheet:

[0167] The nickel-based composite positive electrode material (Ni90): lithium chloride phosphosulfide solid electrolyte (LPSCl): vapor-grown carbon fiber (VGCF): styrene-ethylene-butylene-styrene block copolymer (SEBS) were weighed in a weight ratio of 76:20:2:2. The binder SEBS was dissolved in anisole solvent and magnetically stirred to obtain a 5 wt% binder solution. The Ni90, LPSCl, and conductive agent VGCF were then mixed and dispersed in a ball mill for 30 minutes. The binder solution was then ball-milled and mixed with the mixed materials. The solvent anisole was added to prepare a 65 wt% wet-process positive electrode slurry. The slurry was homogenized and dispersed in a degassing machine for 2 hours. The obtained positive electrode active slurry was intermittently coated on the surface of the positive electrode collector 10 to obtain an array of positive electrode active material layers on the positive electrode collector 10. The size of the positive electrode active material layer was 90*44 mm, and the coating area interval, that is, the interval between two adjacent positive electrode active material layers 112, was 3 mm.

[0168] (2) 3D printing support structure:

[0169] Polytetrafluoroethylene (PTFE), alumina nanoparticles, epoxy resin, polyurethane, and silane coupling agent were added to N-methylpyrrolidone (NMP) in a mass ratio of 50:25:15:7:3 and stirred in a magnetic stirrer for 4 hours to produce an overhang slurry. Using micron-level precision 3D printing equipment, the overhang slurry was precisely printed onto the printed area surrounding the positive active material layer of the positive electrode sheet using an extrusion printing method. The printed area was a hollow foil area, and the overhang slurry filled the empty foil area. The printed support structure had a height of 50μm, with a printing accuracy of ±5μm and a printing speed of 5mm / s. After printing, the sheet was vacuum-dried at 80°C for 5 hours to remove the solvent. The sheet was then roller-pressed to achieve a uniform and flat thickness. The sheet was then die-cut to a size of 92*46 mm, leaving space for the tabs. This resulted in a positive electrode sheet with a support structure.

[0170] Example 4:

[0171] The difference from Example 3 is that in step (2), the overhang slurry uses the slurry in Example 1. Step (2) is specifically as follows:

[0172] (2) 3D printing support structure:

[0173] Polyvinylidene fluoride (PVDF) and aluminum oxide nanoparticles were added to N-methylpyrrolidone (NMP) in a mass ratio of (70-90):(10-30) and stirred in a magnetic stirrer for 4 hours to produce an overhang slurry. Using micron-level precision 3D printing equipment, the overhang slurry was precisely printed onto the printed area surrounding the positive active material layer of the positive electrode sheet using an extrusion printing method. The printed area was a hollow foil area, and the overhang slurry filled the empty foil area. The printed support structure had a height of 50μm, with a printing accuracy of ±5μm and a printing speed of 5mm / s. After printing, the sheet was vacuum-dried at 80℃ for 5 hours to remove the solvent. The sheet was then roller-pressed to achieve a uniform and flat thickness. The sheet was then die-cut to a size of 92*46 mm, leaving the tabs open during die-cutting to produce a positive electrode sheet with a support structure.

[0174] Comparative Example 1:

[0175] The difference from Example 1 is that step (2) is not included, that is, no supporting structure is constructed on the positive electrode sheet, and the remaining steps are the same as those in Example 1.

[0176] The short-circuit rate test results and charge-discharge test results of the solid-state batteries made from the positive electrode sheets of each embodiment and comparative example are shown in Table 1, where the short-circuit rate is tested using a multimeter:

[0177]

[0178] It can be seen from the data in Table 1 that, compared with Comparative Example 1, the solid-state batteries made from the positive electrode sheets of Examples 1 to 4 of the present invention greatly reduced the short-circuit rate, indicating that the 3D printed support structure can alleviate the short-circuit problem caused by pressure during battery assembly testing, reduce the short-circuit risk, and improve the safety of the battery.

[0179] In addition, the use of hot-melt material as the supporting structure in Example 2 can improve interface contact and further enhance battery performance.

[0180] The electrode plates of the present invention are prepared by a method combining 3D printing and intermittent coating, which greatly improves the utilization rate of the electrode collector. The improvement of the utilization rate of the electrode collector also reduces the waste of raw materials and greatly reduces production costs.

[0181] The process used in Example 3 and Example 4 is to print the overhang support structure first and then perform die-cutting. The electrochemical performance of Example 3 and Example 4 is not much different from that of Example 1 and 2, indicating that different die-cutting orders can guarantee the final electrochemical performance of the solid-state battery. However, the rates of available pole pieces prepared in Example 3 and Example 4 are different. Due to the large difference in the toughness of the overhang slurry, the number of available pole pieces obtained during die-cutting is quite different. Example 3 uses the improved overhang slurry, so the available pole piece rate is 95%, and the available pole piece rate obtained by die-cutting in Example 4 is 40%, and the battery yield is low. It can be seen that by improving the overhang slurry, the process can be simplified, efficiency can be improved, while the waste of pole pieces can be reduced and the battery yield can be improved.

[0182] 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.

[0183] 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.

[0184] 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 boxes 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 method for preparing an electrode plate, characterized in that: include: intermittently coating the electrode active slurry on the electrode current collector to obtain a first electrode sheet structure, wherein the first electrode sheet structure comprises an electrode active material layer and a hollow foil area around the electrode active material layer; An electrode electrode is obtained by printing an overhang slurry on a hollow foil area of ​​the first electrode structure using a 3D printing method to form a support structure; wherein the support structure is used to support the overhang area, at least one side of the negative electrode extends beyond the positive electrode to form the overhang area, and the battery cell is provided with an overhang gap area corresponding to the overhang area, and the support structure is located in the overhang gap area; The height of the support structure is 40 μm to 60 μm; Among them, the overhang slurry includes a polymer base, an insulating inorganic filler and a solvent, the solid content of the overhang slurry is 50% to 80%, and the mass ratio of the polymer base and the insulating inorganic filler is (70 to 90): (10 to 30); or, the overhang slurry includes a hot-melt material; the insulating inorganic filler includes a two-dimensional layered powder, and the overhang slurry also includes inorganic solid electrolyte particles, 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 0.01μm to 2μm, wherein the mass percentage of the first inorganic solid electrolyte particles with a particle size in the range of 0.01μm to 0.3μm is 25% to 50%; the two-dimensional size of the two-dimensional layered powder is 0.6μm to 2μm; some inorganic solid electrolyte particles are embedded in the interlayer and / or sheet surface of the two-dimensional layered powder.

2. The method for preparing an electrode sheet according to claim 1, wherein: The electrode active slurry is intermittently coated on the electrode current collector to obtain a first electrode sheet structure, including: intermittently coating the electrode active slurry on the coating area of ​​the electrode current collector to obtain an electrode current collector having multiple electrode active material layers, wherein the multiple electrode active material layers are arranged at intervals; The electrode current collector having multiple electrode active material layers is dried and rolled, and die-cut along the gap between two adjacent electrode active material layers, and an empty foil area is reserved around each electrode active material layer to obtain multiple first electrode sheet structures.

3. The method for preparing an electrode sheet according to claim 2, wherein: The overhang slurry is printed and arranged on the empty foil area of ​​the first electrode structure by a 3D printing method to form a support structure, thereby obtaining an electrode electrode, including: The overhang slurry is printed on the empty foil area of ​​each first pole piece structure by a 3D printing method to obtain a printed first pole piece structure; Drying or curing the printed first pole piece structure to obtain a first pole piece structure with a support structure; The first pole piece structure with the support structure is rolled to obtain an electrode pole piece.

4. The method for preparing an electrode sheet according to claim 1, wherein: The electrode active slurry is intermittently coated on the electrode current collector to obtain a first electrode sheet structure, including: The electrode active slurry is intermittently coated on the coating area on the electrode current collector to obtain a first electrode sheet structure having multiple electrode active material layers; wherein the first electrode sheet structure includes multiple spaced electrode active material layers and a printing area around the electrode active material layer, and the printing area includes a hollow foil area.

5. The method for preparing an electrode sheet according to claim 4, characterized in that: The overhang slurry is printed and arranged on the empty foil area of ​​the first electrode structure by a 3D printing method to form a support structure, thereby obtaining an electrode electrode, including: The second pole piece structure is obtained by printing the overhang slurry on the empty foil area of ​​the first pole piece structure by a 3D printing method; curing or drying the second pole piece structure to form a second pole piece structure having a support structure; The second electrode plate structure with the support structure is rolled and die-cut along the printing area to obtain multiple electrode plates; wherein the printing area is located outside the electrode active material layer, and a support structure is left around the electrode active material layer of each electrode plate.

6. The method for preparing an electrode sheet according to claim 5, characterized in that: The printing area is an empty foil area, or the printing area includes an empty foil area and a cutting area, the cutting area is located on a side of the empty foil area away from the electrode active material layer corresponding to the empty foil area, and no overhang slurry is provided in the cutting area.

7. The method for preparing an electrode sheet according to claim 6, wherein: In the case where the printed area is a blank foil area, die-cutting is performed along the printed area, comprising: die-cutting along the blank foil area; and / or, In the case that the printing area includes the cutting area and the empty foil area, die-cutting is performed along the printing area, including: die-cutting is performed along the cutting area.

8. The method for preparing an electrode sheet according to any one of claims 1 to 7, characterized in that: The width of the support structure is 0.5 mm to 1 mm; and / or, The distance between two adjacent electrode active material layers is greater than or equal to 3 mm; and / or, The length of any electrode active material layer is 80 mm to 100 mm, and the width of the electrode active material layer is 35 mm to 50 mm.

9. An overhang slurry, characterized in that: As an overhang slurry for the method for preparing an electrode sheet according to any one of claims 1 to 8, wherein the overhang slurry comprises a polymer substrate, an insulating inorganic filler, and a solvent, the solid content of the overhang slurry is 50% to 80%, and the mass ratio of the polymer substrate to the insulating inorganic filler is (70-90):(10-30); or, the overhang slurry comprises a hot-melt material; The insulating inorganic filler includes a two-dimensional layered powder, and the overhang slurry also includes inorganic solid electrolyte particles. 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 0.01μm to 2μm, of which the mass percentage of the first inorganic solid electrolyte particles with a particle size in the range of 0.01μm to 0.3μm is 25% to 50%; the two-dimensional size of the two-dimensional layered powder is 0.6μm to 2μm; some inorganic solid electrolyte particles are embedded in the interlayer and / or sheet surface of the two-dimensional layered powder.

10. The overhang slurry according to claim 9, characterized in that The polymer substrate comprises a polymer binder that cures in situ to form a film; and / or, The polymer substrate includes one or more of polytetrafluoroethylene, polyvinylidene fluoride, polyisobutylene, polyetheretherketone, styrene-butadiene rubber, polyethylene oxide, polyimide, polyacrylonitrile, sodium carboxymethyl cellulose, UV adhesive, photosensitive adhesive, and thermal crosslinking; and / or, The insulating inorganic filler comprises one or more of alumina, boron nitride and silicon dioxide; and / or, The solvent includes one or more of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, isopropyl alcohol, toluene, xylene and dimethylformamide; and / or, The overhang slurry further comprises functional additives, which include one or more of a toughening agent, a surfactant and a cross-linking agent.

11. The overhang slurry according to claim 10, characterized in that 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 μm 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 μm 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%.

12. The overhang slurry according to claim 11, characterized in that The particle size ratio of the second inorganic solid electrolyte particles having a particle size in the range of 0.3 μm to 0.6 μm to the first inorganic solid electrolyte particles is 1:(0.03-0.4); and / or, The particle size ratio of the third inorganic solid electrolyte particles having a particle size in the range of 0.6 μm to 2 μm to the second inorganic solid electrolyte particles having a particle size in the range of 0.3 μm to 0.6 μm is 1:(0.25-0.6); and / or, The mass ratio of the second inorganic solid electrolyte particles having a particle size within the range of 0.3 μm 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 0.6μm to 2μm, the second inorganic solid electrolyte particles with a particle size in the range of 0.3μm to 0.6μm, and the first inorganic solid electrolyte particles is (0~2):(4~7):(3~6); and the mass ratio of the third inorganic solid electrolyte particles is not 0.

13. The overhang slurry according to any one of claims 9 to 12, characterized in that When the electrode plate is prepared by the electrode material preparation method according to any one of claims 4 to 8, the overhang slurry includes a polymer base, an insulating inorganic filler, a solvent, a cross-linking agent, a toughening agent and a surfactant.

14. The overhang slurry according to claim 13, characterized in that The solid content of the overhang slurry is 60% to 75%, or the solid content of the overhang slurry is 65% to 75%, or the solid content of the overhang slurry is 60% to 70%; and / or, The mass ratio of polymer substrate, insulating inorganic filler, crosslinking agent, toughening agent and surfactant is (40-60):(20-30):(5-15):(5-10):(1-3); and / or, The polymer substrate comprises one or more of polytetrafluoroethylene, polyimide, polyisobutylene and polyetheretherketone; and / or, The solvent includes one or more of N-methylpyrrolidone, isopropyl alcohol, toluene, and xylene; and / or, The crosslinking agent includes one or more of epoxy resin, polyurethane, acrylate, and silane crosslinking agent; and / or, The toughening agent includes one or more of polyurethane, polyethylene, polypropylene and ethylene-vinyl acetate copolymer; and / or, The surfactant includes one or more of polyvinyl alcohol, sodium lauryl sulfate, sodium alkylbenzene sulfonate, polyoxyethylene alcohol ether and silane coupling agent.

15. A positive electrode plate, characterized in that: The positive electrode sheet is prepared using the method for preparing an electrode sheet according to any one of claims 1 to 8, or the support structure of the positive electrode sheet is prepared using the overhang slurry according to any one of claims 9 to 14.

16. A battery cell, characterized in that: The battery cell comprises alternating stacked positive and negative electrode sheets, with a solid electrolyte layer disposed 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 region, the battery cell is provided with an overhang gap region corresponding to the overhang region, and the support structure is located in the overhang gap region; Wherein, the positive electrode plate adopts the positive electrode plate as claimed in claim 15.

17. A solid-state battery, characterized in that: include: The battery cell according to claim 16.

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