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

Abstract

The invention relates to the technical field of solid-state batteries, and discloses 3D printing overhang slurry which comprises a polymer substrate, a functional material and a solvent, the functional material comprises one or more of an oxygen adsorbent, a water adsorbent and a heat absorbent, the solid content of the 3D printing overhang slurry is 20%-80%, and the mass ratio of the polymer substrate to the functional material is (70-90): (10-30). The packaging structure has the functions of adsorbing water and oxygen, absorbing heat, relieving stress and the like, so that an effective prevention means is provided for the problems of leakage, temperature rise, expansion and the like which are easy to occur in the running process of the solid-state battery, an overhang gap is fully utilized, and the function of the solid-state battery is improved. The invention further discloses an electrode plate, a battery cell, a preparation method of the battery cell and a solid-state battery.

Description

Technical Field

[0001] The present application relates to the technical field of solid-state batteries, for example, to a 3D printing overhang paste, an electrode sheet, a battery cell, and their preparation methods and solid-state batteries. Background Art

[0002] In recent years, with the continuous growth of energy storage demand and the increasingly stringent performance requirements for battery safety, energy density, etc., solid-state batteries, as a new battery technology with great development potential, have received extensive attention and in-depth research. Compared with traditional liquid batteries, solid-state batteries use solid electrolytes to replace liquid electrolytes and have many significant advantages, such as higher energy density, better safety, and a wider operating temperature range, etc., and are expected to be widely applied in many fields such as electric vehicles, portable electronic devices, and large-scale energy storage systems. However, in the development process of solid-state batteries, there are also some technical challenges that need to be solved urgently. For example, the problem of short circuit caused by uneven stress due to the overhang region is one of the key factors affecting the performance and safety of solid-state batteries. There are also problems such as the instability of sulfide electrolytes to water and oxygen, and the easy occurrence of thermal runaway when paired with ternary cathodes, etc., which pose challenges to the battery operating environment, the control of oxygen release from the cathode, the control of battery temperature, etc.

[0003] The negative overhang region refers to the part where the negative electrode sheet extends beyond the positive electrode sheet in the length and / or width direction. This design is mainly to prevent lithium dendrites from precipitating on the surface of the negative electrode during charging, piercing the separator and causing internal short circuit of the battery, triggering thermal runaway, and improving the safety of the battery. However, the height difference generated in the overhang region will cause uneven stress in the solid-state battery during pressure forming and pressure operation. This uneven stress easily leads to deformation of the edges of the electrode and the solid electrolyte, and may even cause local delamination, cracking, etc., ultimately resulting in a short circuit fault inside the battery, seriously affecting the service life, charge and discharge performance, and overall safety of the battery.

[0004] To address the problem of easy occurrence of battery short circuit in the negative overhang region of solid-state batteries, most methods are to set / fill substances (corresponding to the encapsulation structure of the present application) in the overhang gap corresponding to the negative overhang region for support, relieve the uneven stress caused by the overhang, ensure the interfacial stability between the electrode and the solid electrolyte, and thus reduce the occurrence of short circuits. Or, an insulating coating is set at the edge of the positive electrode sheet, and its insulating property is used to replace the role of the overhang region, which can effectively avoid the risk of short circuit caused by abnormal contact at the edge of the electrode sheet.

[0005] Currently, methods for setting / filling substances in the overhang gap generally include coating methods, pouring methods, etc. However, these methods for setting / filling substances cannot effectively control the amount of substances set / filled during the setting / filling process, resulting in the filling of the overhang gap not achieving the expected effect. Setting an insulating coating on the edge of the positive electrode tab alleviates the stress problem caused by the overhang region to a certain extent. However, the area where the insulating coating is set is not utilized, and it will also cause an increase in the battery mass.

[0006] It should be noted that the information disclosed in the above background art section is only used to enhance the understanding of the background of the present application. Therefore, it may include information that does not constitute the prior art known to those of ordinary skill in the art. Summary of the Invention

[0007] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. The summary is not a comprehensive review, nor is it intended to identify key / important elements or delineate the scope of protection of these embodiments. Instead, it serves as a prelude to the detailed description that follows.

[0008] Embodiments of the present disclosure provide a 3D printing overhang slurry, an electrode tab, a battery cell, and their preparation methods, and a solid-state battery. The 3D printing overhang slurry is applicable to 3D printing methods, can absorb the stress of the volume change of the electrodes of the solid-state battery, alleviate the interface failure problem caused by local stress, and improve the performance of the solid-state battery.

[0009] In some embodiments, the 3D printing overhang slurry includes: a polymer substrate, a functional material, and a solvent. The functional material includes one or more of an oxygen adsorbent, a water adsorbent, and an endothermic agent. Among them, the solid content of the 3D printing overhang slurry is 20% - 80%, and the mass ratio of the polymer substrate to the functional material is (70 - 90):(10 - 30).

[0010] In some embodiments, the preparation method of the 3D printing overhang slurry includes: preparing each raw material according to the aforementioned 3D printing overhang slurry; adding the polymer substrate to the solvent to obtain solution A; adding the functional material to solution A to obtain the 3D printing overhang slurry.

[0011] In some embodiments, the electrode tab, the electrode tab is a positive electrode tab or a negative electrode tab; when the electrode tab includes a positive electrode tab, the positive electrode tab includes an empty foil area, and a 3D printed overhang paste is provided in the empty foil area; when the electrode tab includes a negative electrode tab, the negative electrode tab includes an overhang area, and a 3D printed overhang paste is provided in the overhang area of the negative electrode tab; when the electrode tab includes a negative electrode tab and the negative electrode tab is a combined negative electrode tab provided with solid electrolyte layers on both of its side surfaces, a 3D printed overhang paste is provided on the surface of the solid electrolyte layer of the combined negative electrode tab corresponding to the overhang area of the negative electrode tab; wherein, the 3D printed overhang paste is the aforementioned 3D printed overhang paste or the 3D printed overhang paste obtained by the preparation method of the aforementioned 3D printed overhang paste.

[0012] In some embodiments, the battery cell includes a stacked structure, the stacked structure includes alternately stacked positive electrode tabs and negative electrode tabs, and a solid electrolyte layer is provided between adjacent positive electrode tabs and negative electrode tabs; at least one side of the negative electrode tab in the circumferential direction extends beyond the positive electrode tab to form an overhang area; wherein, a packaging structure is provided in the overhang void area corresponding to the overhang area; wherein, the packaging structure is obtained by disposing the 3D printed overhang paste in the overhang void area; the 3D printed overhang paste is the aforementioned 3D printed overhang paste or the 3D printed overhang paste obtained by the preparation method of the aforementioned 3D printed overhang paste.

[0013] In some embodiments, the preparation method of the battery cell includes: preparing a positive electrode tab, a negative electrode tab and a solid electrolyte layer; wherein, the size of the negative electrode tab is larger than that of the positive electrode tab at least on one side in the circumferential direction, so that the negative electrode tab has an overhang area; wherein, the positive electrode tab uses the aforementioned positive electrode tab, or the negative electrode tab uses the aforementioned negative electrode tab or a combined negative electrode tab; alternately stacking the positive electrode tab and the negative electrode tab, and providing a solid electrolyte layer between adjacent positive electrode tabs and negative electrode tabs to obtain a battery cell; wherein, a cured 3D printed overhang paste is provided at the overhang void of the battery cell.

[0014] In some embodiments, the preparation method of the battery cell includes: stacking a positive electrode tab, a solid electrolyte layer, a negative electrode tab and a solid electrolyte layer in this order to obtain a stacked structure; wherein, an overhang void area is formed on the circumferential side surface of the stacked structure; disposing a 3D printed overhang paste in the overhang void area of the stacked structure to obtain a battery cell with a packaging structure.

[0015] In some embodiments, the solid-state battery includes: the aforementioned electrode sheet; or, the aforementioned battery cell; or a battery cell obtained by the preparation method of the aforementioned battery cell.

[0016] The 3D printing overhang paste, electrode sheet, battery cell, their preparation methods, and solid-state battery provided by the embodiments of the present disclosure can achieve the following technical effects: In the 3D printing overhang paste of the embodiments of the present disclosure, the paste has fluidity through the polymer substrate and the solvent. When the solid content of the 3D printing overhang paste is between 20% and 80%, the solid content and rheological properties of the paste can be taken into account, enabling the overhang paste to be suitable for the 3D printing method, ensuring both the printing strength and the smoothness of printing, so as to obtain a packaging structure with the expected effect at the overhang gap and solve the problem of edge collapse and short circuit of the solid-state battery.

[0017] Meanwhile, the 3D printing overhang paste also contains functional materials, and the mass ratio of the polymer substrate to the functional materials is maintained within the scope of this solution. In this way, the packaging structure can also take into account functions such as adsorbing water and oxygen, absorbing heat, and relieving stress, providing an effective preventive means for problems such as leakage, temperature rise, and expansion that are likely to occur during the operation of the solid-state battery. In this way, the 3D printing overhang paste provided by the embodiments of the present disclosure can not only play a supporting role, but also enable the packaging structure formed by the 3D printing overhang paste to have other functions to ensure the stable and safe operation of the solid-state battery, making full use of the overhang gap, and thus improving the performance of the solid-state battery.

[0018] The electrode sheet of the embodiments of the present disclosure can print and set an overhang packaging structure through the 3D printing method, can accurately control the printing amount, and thus can well control parameters such as the thickness and uniformity of the packaging structure, and has a fast printing speed and high efficiency.

[0019] The above general description and the following description are only exemplary and explanatory, and are not used to limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] One or more embodiments are exemplarily illustrated by corresponding drawings. These exemplary illustrations and the drawings do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a scale limitation, and among them: Figure 1 is a schematic structural diagram of an existing solid-state battery provided by the embodiments of the present disclosure; Figure 2 is a schematic structural diagram of a packaging structure provided by the embodiments of the present disclosure; Figure 3It is a schematic diagram of a partial structure of a solid-state battery prepared in Example 1 provided by an embodiment of the present disclosure; Figure 4 It is a schematic diagram of a partial structure of a solid-state battery prepared in Example 2 provided by an embodiment of the present disclosure; Figure 5 It is a schematic diagram of a partial structure of a solid-state battery prepared in Example 3 provided by an embodiment of the present disclosure; Figure 6 It is a schematic diagram of an exploded structure of a solid-state battery prepared in Example 1 provided by an embodiment of the present disclosure; Figure 7 It is a schematic diagram of an exploded structure of a solid-state battery prepared in Example 2 provided by an embodiment of the present disclosure; Figure 8 It is a schematic diagram of an exploded structure of a solid-state battery prepared in Example 3 provided by an embodiment of the present disclosure; Figure 9 It is a schematic diagram of the structure of an electric core provided by an embodiment of the present disclosure; Figure 10 It is a schematic diagram of a partially enlarged structure of another electric core provided by an embodiment of the present disclosure; Figure 11 It is a flowchart of a preparation method of a 3D printed overhang slurry provided by an embodiment of the present disclosure; Figure 12 It is a flowchart of a preparation method of an electric core provided by an embodiment of the present disclosure; Figure 13 It is a flowchart of a preparation method of another electric core provided by an embodiment of the present disclosure; Figure 14 It is a flowchart of a preparation method of yet another electric core provided by an embodiment of the present disclosure.

[0021] Reference numerals: 10: Stacked structure; 11: Negative electrode tab; 111: Overhang region; 112: Negative electrode active material layer; 113: Negative electrode current collector; 12: Positive electrode tab; 121: Positive electrode active material layer; 122: Positive electrode current collector; 13: Solid electrolyte layer; 2: Encapsulation structure; 21: Filling part; 211: Support part; 212: Penetration part; 22: Coating part. Detailed implementation manners

[0022] In order 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 will be described in detail below with reference to the accompanying drawings. The attached drawings are for reference and illustration only, and are not intended to limit the embodiments of the present disclosure. In the following technical description, for the sake of explanation, numerous details are provided to give a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be shown in a simplified manner to simplify the drawings.

[0023] In the description of the embodiments of the present disclosure, the terms "first", "second", etc. in the specification, claims and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances so as to understand the embodiments of the present disclosure described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0024] In the embodiments of the present disclosure, the orientation or positional relationships indicated by the terms "upper", "lower", "inner", "middle", "outer", "front", "rear", etc. are based on the orientation or positional relationships shown in the drawings. These terms are mainly used to better describe the embodiments of the present disclosure and their implementations, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation. And, in addition to being able to represent orientation or positional relationships, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. 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.

[0025] In addition, the terms "arranged", "connected", "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0026] Unless otherwise specified, the term "plurality" means two or more.

[0027] In the embodiments of the present disclosure, the character " / " indicates that the objects before and after are in an "or" relationship. For example, A / B means: A or B.

[0028] The term "and / or" is an associative relationship describing an object, indicating that there can be three relationships. For example, A and / or B means: A or B, or, A and B these three relationships.

[0029] It should be noted that, without conflict, the embodiments in the present disclosure and the features in the embodiments may be combined with each other.

[0030] The embodiments of the present disclosure provide a 3D printing overhang slurry, including: a polymer substrate, a functional material, and a solvent, wherein the functional material includes one or more of an oxygen adsorbent, a water adsorbent, and an endothermic agent.

[0031] In the 3D printing overhang slurry, the polymer substrate and the solvent take into account both high solid content and rheological properties, enabling it to be applicable to 3D printing methods, achieving printability and high strength of the high-solid-content slurry, ensuring both printing strength and printing smoothness, and thus enabling an encapsulation structure 2 with the desired effect to be obtained at the overhang gap, solving the problem of edge collapse and short circuit of the solid-state battery. At the same time, the 3D printing overhang slurry also contains functional materials, so that the encapsulation structure 2 can also take into account functions such as adsorbing water, oxygen, endothermic heat, and relieving stress, providing effective preventive means for problems such as leakage, temperature rise, and expansion that are likely to occur during the operation of the battery. During the cycling of the solid-state battery, the functional materials can quench the oxygen generated in the positive electrode or the water / oxygen leaked from the environment, slow down the decomposition of the solid electrolyte, especially the sulfide solid electrolyte, reduce side reactions in the solid-state battery, and also improve the thermal stability of the solid electrolyte. Combining with the elastic characteristics of the polymer, it absorbs the stress of the volume change of the electrodes of the solid-state battery, relieves the interface failure problem caused by local stress, and improves the performance of the solid-state battery.

[0032] Optionally, the solid content of the 3D printing overhang slurry is 20% - 80%, or the solid content of the 3D printing overhang slurry is 20% - 60%, or the solid content of the 3D printing overhang slurry is 35% - 60%, or the solid content of the 3D printing overhang slurry is 60% - 75%, or the solid content of the 3D printing overhang slurry is 60% - 80%, or any value within the range of 20% - 80% of the solid content of the 3D printing overhang slurry.

[0033] The 3D printing overhang slurry of the embodiments of the present disclosure, with the solid content within the above range, realizes the balance of the rheological properties and high solid content of the slurry, enables a reasonable number of solid-phase particles in the 3D printing overhang slurry, suitable particle spacing, and thus reasonable rheology, making it applicable to 3D printing methods, ensuring the processability and stability of 3D printing, and ensuring the strength and density of the printed overhang encapsulation structure 2. It can be understood that the solid content of the 3D printing overhang slurry can be mass solid content or volume solid content, without limitation.

[0034] Optionally, the solid content of the 3D printed overhang paste is a mass solid content. The adjustment of the solid content is achieved by the addition amount of the solvent, that is, the amount of the solvent in the 3D printed overhang paste of the present disclosure is determined according to the solid content of the paste. The type of the solvent is not limited.

[0035] Optionally, the solid content of the 3D printed overhang paste is any value within the range of 20%, 30%, 35%, 40%, 45%, 50%, 60%, 65%, 75% or 20% - 80%.

[0036] Optionally, the mass percentage of the polymer substrate in the dry solid content of the 3D printed overhang paste is 60% - 90%, or the mass percentage of the polymer substrate in the dry solid content of the 3D printed overhang paste is 70% - 90%, or the mass percentage of the polymer substrate in the dry solid content of the 3D printed overhang paste is 60% - 80%, or the mass percentage of the polymer substrate in the dry solid content of the 3D printed overhang paste is any value within the range of 60% - 90%.

[0037] For the 3D printed overhang paste of the embodiments of the present disclosure, the overall proportion of the polymer substrate in the solid content in the 3D printed overhang paste is within the above range, which can provide sufficient elasticity and strength for the encapsulation structure 2, thereby ensuring that the encapsulation structure has sufficient supporting force and buffering force, and ensuring that the encapsulation structure 2 has sufficient mechanical strength and thermal stability.

[0038] Optionally, the mass percentage of the polymer substrate in the dry solid content of the 3D printed overhang paste is 60%, 65%, 70%, 75%, 80%, 90% or any value within the range of 60% - 90%.

[0039] The mass of the solid content in the 3D printed overhang paste refers to the mass of the solid after drying in the 3D printed overhang paste.

[0040] Optionally, the mass percentage of the functional material in the solid content of the 3D printed overhang paste is 5% - 40%, or the mass percentage of the functional material in the solid content of the 3D printed overhang paste is 10% - 40%, or the mass percentage of the functional material in the solid content of the 3D printed overhang paste is 10% - 35%, or the mass percentage of the functional material in the solid content of the 3D printed overhang paste is 10% - 30%, or the mass percentage of the functional material in the solid content of the 3D printed overhang paste is any value within the range of 5% - 40%.

[0041] For the 3D printed overhang slurry according to the embodiments of the present disclosure, when the content of the functional material is within the above range, it can not only regulate the microenvironment inside the battery to protect the battery, but also ensure the mechanical strength and stability of the encapsulation structure 2, and ensure the supporting effect of the encapsulation structure 2 on the overhang.

[0042] Optionally, the mass percentage of the functional material in the solid content of the 3D printed overhang slurry is 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40% or any value within 5% - 40%.

[0043] Optionally, the mass ratio of the polymer substrate to the functional material is (70 - 90) : (10 - 30).

[0044] For the 3D printed overhang slurry according to the embodiments of the present disclosure, the mass of the polymer substrate is greater than that of the functional material. In this way, the polymer substrate absorbs the stress of the volume change of the electrodes of the solid-state battery, alleviates the interfacial failure problem caused by local stress, and improves the performance of the solid-state battery. The functional material enables the encapsulation structure 2 to also have specific functions, providing effective preventive means for problems such as leakage, temperature rise, and expansion that are prone to occur during the operation of the battery. The mass ratio of the polymer substrate to the functional material within the above range realizes the balance of the mechanical strength and function of the encapsulation structure 2.

[0045] Optionally, the mass ratio of the polymer substrate to the functional material is 70:30, 80:30, 90:30, 70:20, 80:20, 90:20, 70:10, 80:10, 90:10, etc.

[0046] Optionally, the polymer substrate includes one or more of polyisobutylene, polyphenylene ether, polyimide, polyacrylonitrile, polyvinylidene fluoride, polyethylene glycol, polyethylene oxide, sodium carboxymethyl cellulose, styrene-butadiene rubber, and polyacrylic acid.

[0047] For the 3D printed overhang slurry according to the embodiments of the present disclosure, using the above materials for the polymer substrate enables the encapsulation structure 2 to have sufficient strength to ensure the supporting effect on the overhang. And these materials also have a moderate elastic modulus and viscoelasticity, so that the encapsulation structure 2 can provide support but is not brittle, can provide good stress buffering, ensure the interfacial stability between the electrode and the solid electrolyte, and thus reduce the occurrence of short-circuit situations.

[0048] Optionally, the solvent includes one or more of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethylformamide.

[0049] Optionally, the water adsorbent includes one or more of zeolite, calcium chloride, magnesium chloride, sodium polyacrylate, and polyvinyl alcohol.

[0050] For the 3D printed overhang slurry according to the embodiments of the present disclosure, the above materials can be used as the water adsorbent, which can efficiently adsorb the residual moisture in the battery and reduce side reactions in the solid-state battery.

[0051] Optionally, the oxygen adsorbent includes one or more of polydopamine, lithium phytate, 4-tert-butylcatechol, N-phenyl-N'-phenyl-p-phenylenediamine, naphthylamine, diphenylamine, and p-phenylenediamine.

[0052] For the 3D printed overhang slurry according to the embodiments of the present disclosure, when the above materials are used as the oxygen adsorbent, during the cycling of the solid-state battery, the oxygen adsorbent may be able to quench the oxygen generated in the positive electrode or the oxygen leaked from the environment, avoid the oxidation reaction of the active substances in the electrode with oxygen, thereby preventing the electrode from being oxidized and corroded, slowing down the decomposition of the solid electrolyte, especially the sulfide solid electrolyte, reducing side reactions in the solid-state battery, and also improving the thermal stability of the solid electrolyte.

[0053] Optionally, the heat absorbent includes one or more of polyethylene glycol and polyvinyl alcohol.

[0054] For the 3D printed overhang slurry according to the embodiments of the present disclosure, using the above materials as the heat absorbent can effectively absorb the heat generated during the operation of the battery, absorb local hot spots, and ensure the safety of the battery.

[0055] Optionally, when the polymer substrate includes a first polymer and a second polymer, the elastic modulus of the first polymer is greater than that of the second polymer, and the strength of the second polymer is greater than that of the first polymer; wherein, the mass percentage of the first polymer in the polymer substrate is 50% - 80%, or the mass percentage of the first polymer in the polymer substrate is 50% - 75%, or the mass percentage of the first polymer in the polymer substrate is 60% - 75%; the mass percentage of the second polymer in the polymer substrate is 20% - 60%, or the mass percentage of the second polymer in the polymer substrate is 25% - 50%, or the mass percentage of the second polymer in the polymer substrate is 25% - 40%.

[0056] For the 3D printed overhang slurry according to the embodiments of the present disclosure, the polymer substrate can use a variety of polymer composites, combining high-elasticity and high-strength materials, so that the encapsulation structure 2 can not only resist external impacts and restrain expansion, but also has good flexibility and can adapt to the overall expansion and contraction of the battery without cracking.

[0057] Optionally, the mass percentage of the first polymer in the polymer substrate is 50%, 55%, 60%, 65%, 70%, 75%, 80% or any value within 50% - 80%.

[0058] Optionally, the mass percentage of the second polymer in the polymer substrate is 20%, 25%, 20%, 30%, 35%, 40%, 45%, 50%, 60% or any value within 20% - 60%.

[0059] Optionally, when the functional material includes an oxygen adsorbent, the mass percentage of the oxygen adsorbent in the functional material is 10% - 60%, or the mass percentage of the oxygen adsorbent in the functional material is 10% - 50%, or the mass percentage of the oxygen adsorbent in the functional material is 20% - 50%, or any range within 10% - 60% of the mass percentage of the oxygen adsorbent in the functional material.

[0060] For the 3D printing overhang slurry of the embodiments of the present disclosure, within the above ranges, the oxygen adsorbent can effectively ensure the oxygen adsorption of the oxygen adsorbent and inhibit the role of oxidation side reactions. At the same time, the functional material can also be mixed with other functional materials to improve the versatility of the encapsulation structure 2 and comprehensively protect the safety, use stability and service life of the battery.

[0061] Optionally, when the functional material includes an oxygen adsorbent, the mass percentage of the oxygen adsorbent in the functional material is 10%, 20%, 30%, 40%, 50%, 60% or any value within the range of 10% - 60%.

[0062] Optionally, when the functional material includes a water adsorbent, the mass percentage of the water adsorbent in the functional material is 20% - 70%, or the mass percentage of the water adsorbent in the functional material is 20% - 60%, or the mass percentage of the water adsorbent in the functional material is 30% - 60%, or any range within 20% - 70% of the mass percentage of the water adsorbent in the functional material.

[0063] For the 3D printing overhang slurry of the embodiments of the present disclosure, when the content of the water adsorbent is within the above ranges, it can effectively prevent water vapor from entering the internal of the battery cell and prevent hydrolysis reactions of the electrode materials and electrolytes in the battery cell, so as to maintain the appropriate viscosity and stability of the 3D printed slurry.

[0064] Optionally, when the functional material includes a water adsorbent, the mass percentage of the water adsorbent in the functional material is 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 70% or any value within 20% - 70%.

[0065] Optionally, when the functional material includes a heat absorber, the mass percentage of the heat absorber in the functional material is 20% to 100%, or the mass percentage of the heat absorber in the functional material is 20% to 40%, or the mass percentage of the heat absorber in the functional material is 60% to 100%, or the mass percentage of the heat absorber in the functional material is 80% to 100%, or any value within the range of 20% to 100% of the mass percentage of the heat absorber in the functional material.

[0066] For the 3D printing overhang slurry of the embodiments of the present disclosure, within the above range, the heat absorber can effectively absorb part of the heat during the operation of the battery cell, reduce the local temperature of the battery cell, and prevent safety problems such as thermal runaway caused by overheating of the battery cell. Moreover, it can also relieve the thermal stress generated due to the temperature difference between the slurry and the inside of the battery cell, reduce phenomena such as cracking and deformation of the encapsulation structure 2, and improve the integrity and reliability of the encapsulation structure 2.

[0067] Optionally, the mass percentage of the heat absorber in the functional material is 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% or any value within the range of 20% to 100%.

[0068] Optionally, the functional material includes auxiliary additives, and the auxiliary additives include one or more of a reinforcing agent, a compatibilizer, a coupling agent, a surfactant, and an inorganic filler. This can further improve the function of the encapsulation structure 2.

[0069] Optionally, the functional material includes auxiliary additives, and the mass percentage of the auxiliary additives in the functional material is 0 to 40%, or the mass percentage of the auxiliary additives in the functional material is 10% to 40%, or the mass percentage of the auxiliary additives in the functional material is 20% to 40%. By mixing different auxiliary additives, the function of the 3D printing overhang slurry is further improved. When there are multiple auxiliary additives, the ratio of each auxiliary additive is not limited.

[0070] Optionally, the reinforcing agent includes hydrophobic fumed silica, which can enhance the barrier property and wear resistance of the coating.

[0071] In some alternative embodiments, the 3D printing overhang slurry includes a first slurry, and the solid content of the first slurry is 20% to 65%, or the solid content of the first slurry is 30% to 60%, or the solid content of the first slurry is 35% to 60%, or any range within 20% to 65% of the solid content of the first slurry. For the battery cell of the embodiments of the present disclosure, within the above range of the solid content of the first slurry, the 3D printing overhang slurry has good fluidity and wettability, can penetrate into the inside of the layers of the battery material, and can also take into account the mechanical strength to provide sufficient support stress.

[0072] Optionally, the solid content of the first slurry is 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 65% or any value within the range of 20% to 65%.

[0073] Optionally, the polymer substrate in the first slurry includes one or more of polyvinylidene fluoride, polyacrylonitrile, and polyethylene oxide. Using the above several polymer substrates in the first slurry forms a packaging structure with a certain elastic modulus and viscoelasticity, which can provide flexible support and stress buffering to avoid the fracture of the packaging structure.

[0074] In some embodiments, the solid content of the first slurry is 35% to 60%, and the polymer substrate in the first slurry includes one or more of polyvinylidene fluoride, polyacrylonitrile, and polyethylene oxide. Such a solid content of 35% to 60% enables the 3D printing overhang slurry to have good fluidity, which can not only fill the overhang void area but also penetrate into the interior of the sheet layer, improving the bonding strength between the packaging structure and the battery cell. In addition, using one or more of polyvinylidene fluoride, polyacrylonitrile, and polyethylene oxide in the first slurry makes the 3D printing overhang slurry have a certain elasticity, enabling the formed packaging structure to have a certain deformation ability, improving the cohesion, which can solve the problem of uneven stress caused by the overhang, ensure the interface stability between the electrode and the solid electrolyte, thereby reducing the occurrence of short circuits, and further adapting to the forming pressure of the battery cell and the volume change of the active material, avoiding the detachment and excessive deformation of the packaging structure 2 from the sheet layer and the generation of new edge stresses, thus improving the performance of the solid-state battery.

[0075] Optionally, the functional material in the first slurry includes one or more of an oxygen adsorbent, a water adsorbent, and an endothermic agent.

[0076] In the embodiments of the present disclosure, the functional material enables the packaging structure to not only support the overhang region 111 but also regulate the microenvironment inside the battery cell, reduce side reactions inside the solid-state battery, and improve the thermal stability of the solid-state battery. When the first slurry is disposed inside the sheet layer of the battery cell and can even penetrate between the sheet layers, therefore, adding one or more of an oxygen adsorbent, a water adsorbent, and an endothermic agent to the first slurry can be used to synergistically regulate the environment inside the battery cell. The water adsorbent can efficiently capture the residual moisture inside the battery cell. The oxygen adsorbent can inhibit the oxidation side reactions inside the battery cell, while the endothermic agent can absorb local hot spots, thereby regulating the environment inside the battery cell, and further improving the performance and safety of the solid-state battery while solving the stress problem caused by the overhang region 111.

[0077] Optionally, the mass percentage of the oxygen adsorbent in the first slurry to the functional material is 10% to 60%, or the mass percentage of the oxygen adsorbent in the first slurry to the functional material is 10% to 50%, or the mass percentage of the oxygen adsorbent in the first slurry to the functional material is 20% to 50%, or the mass percentage of the oxygen adsorbent in the first slurry to the functional material is 30% to 60%, or the mass percentage of the oxygen adsorbent in the first slurry to the functional material is any range within 10% to 60%.

[0078] The mass percentage of the oxygen adsorbent in the first slurry to the functional material can be flexibly selected within the above multiple ranges to meet the requirements of oxygen adsorption capacity and comprehensive slurry performance in different application scenarios. For example, for lithium iron phosphate batteries with a relatively low oxygen release intensity at the positive electrode, etc., an oxygen adsorbent with a relatively low content can be used to achieve basic protection and block the slow oxidation of trace oxygen. For some ternary batteries with a general oxygen release intensity at the positive electrode, etc., an oxygen adsorbent with a medium content can be used to inhibit the oxidation and decomposition reaction of ions in the battery. For ternary batteries with a relatively high oxygen release intensity at the positive electrode, an oxygen adsorbent with a relatively high content can be used to strongly capture the release of lattice oxygen and avoid the reaction of oxygen with the electrolyte.

[0079] Optionally, the mass percentage of the oxygen adsorbent in the first slurry to the functional material is 10%, 20%, 30%, 40%, 50%, 60% or any value within the range of 10% to 60%.

[0080] Optionally, the oxygen adsorbent in the first slurry includes one or more of polydopamine nanoparticles, lithium phytate, 4-tert-butylcatechol, N-phenyl-N'-phenyl-p-phenylenediamine, naphthylamine, diphenylamine, p-phenylenediamine.

[0081] Preferably, the oxygen adsorbent in the first slurry includes polydopamine nanoparticles. As an oxygen adsorbent, polydopamine nanoparticles can provide a super high specific surface area and adsorption efficiency, improve the oxygen capture ability per unit mass, and can respond to changes in oxygen concentration as needed, extending the validity period.

[0082] Optionally, the mass percentage of the water adsorbent in the first slurry to the functional material is 20% to 70%, or the mass percentage of the water adsorbent in the first slurry to the functional material is 20% to 60%, or the mass percentage of the water adsorbent in the first slurry to the functional material is 30% to 60%, or the mass percentage of the water adsorbent in the first slurry to the functional material is any range within 20% to 70%.

[0083] The mass percentage of the water adsorbent in the first slurry to the functional material can be adjusted according to various application scenarios. For some special battery cells with extremely high requirements for moisture-proof (such as battery cells working in high-humidity environments), a high proportion of water adsorbent can be selected; while for battery cells in general environments or scenarios with higher requirements for other functions (such as heat absorption, enhancement, etc.), the proportion of the water adsorbent can be appropriately reduced to highlight the role of other functional materials.

[0084] Optionally, the mass percentage of the water adsorbent in the first slurry to the functional material is 20%, 30%, 40%, 50%, 60%, 70% or any value within the range of 20% - 70%.

[0085] Optionally, the water adsorbent in the first slurry includes one or more of zeolite, calcium chloride, magnesium chloride, sodium polyacrylate and polyvinyl alcohol.

[0086] Optionally, the water adsorbent in the first slurry includes zeolite. Zeolite has a low cost, strong adsorption and high adsorption capacity. Zeolite can be well compatible with a variety of polymer substrates and be evenly dispersed in the slurry to form a stable system, without problems such as stratification and precipitation, ensuring the uniformity and consistency of the slurry. It can also work synergistically with other functional materials such as oxygen adsorbents and heat absorbers to jointly perform multiple functions such as adsorbing moisture, oxygen and heat absorption, and realizing the comprehensive optimization of the slurry performance.

[0087] Optionally, the mass percentage of the heat absorber in the first slurry to the functional material is 10% - 50%, or the mass percentage of the heat absorber in the first slurry to the functional material is 20% - 50%, or the mass percentage of the heat absorber in the first slurry to the functional material is 20% - 40%, or the mass percentage of the heat absorber in the first slurry to the functional material is any range within 10% - 50%.

[0088] For the battery cells of the embodiments of the present disclosure, when the mass percentage of the heat absorber is in a relatively high range, the slurry can absorb a large amount of heat, which is suitable for encapsulating battery cells that generate more heat during charge and discharge, such as high-rate lithium-ion batteries or large-capacity energy storage batteries, and can effectively reduce the temperature of the battery cells, avoid safety problems caused by overheating, and maintain the stable operation of the battery cells. When the mass percentage of the heat absorber is in a relatively low range, it can meet the temperature control requirements of battery cells with general heat generation levels, prevent the temperature of the battery cells from being too high, and at the same time reduce the possible changes in the slurry performance or other adverse effects caused by excessive heat absorption, and is applicable to the encapsulation scenarios of most ordinary battery cells.

[0089] Optionally, the mass percentage of the heat absorber in the first slurry to the functional material is 10%, 20%, 30%, 40%, 50% or any value within the range of 10% - 50%.

[0090] Optionally, the heat absorbent in the first slurry includes polyethylene glycol. Polyethylene glycol can absorb a large amount of heat during the phase change between solid and liquid states, effectively reducing the heat generated by the battery cell during charging and discharging, preventing safety problems caused by overheating of the battery cell, maintaining the stable operation of the battery cell, and being able to automatically adjust the heat absorption process according to the temperature change of the battery cell. When the temperature of the battery cell rises, polyethylene glycol absorbs heat and slows down the temperature rise; when the temperature of the battery cell drops, it does not release heat too quickly, which helps to maintain the relative stability of the battery cell temperature.

[0091] In some alternative embodiments, the functional materials in the first slurry include zeolite, polydopamine nanoparticles, and a heat absorbent. Among them, the mass percentage of zeolite in the functional materials is 30–60% to enable zeolite to efficiently capture residual moisture; the mass percentage of polydopamine nanoparticles in the functional materials is 20–50%, which can effectively inhibit oxidation side reactions; the mass percentage of polyethylene glycol in the functional materials is 20–40%, which can absorb local hot spots.

[0092] In another alternative embodiment, the 3D printing overhang slurry further includes a second slurry, and the solid content of the second slurry is 60%–80%, or the solid content of the second slurry is 60%–80%, or the solid content of the second slurry is 60%–75%, or the solid content of the second slurry is within any range of 60%–80%.

[0093] For the battery cell of the embodiments of the present disclosure, with the solid content of the second slurry within the above range, a rigid and tough dense encapsulation structure 2 can be formed, which can better seal the edge of the electrode sheet or the bonding part of the diaphragm end face, etc., improve the sealing effect of the battery cell, and isolate oxygen, water, etc. in the external environment.

[0094] Optionally, the solid content of the second slurry is 60%, 65%, 70%, 75%, 80%, 85%, 90% or any value within the range of 60%–90%.

[0095] Optionally, the polymer substrate in the second slurry includes a first polymer and a second polymer. The elastic modulus of the first polymer is greater than that of the second polymer, and the strength of the second polymer is greater than that of the first polymer. Among them, the content of the first polymer is greater than that of the second polymer, or the mass percentage of the first polymer in the polymer substrate is 50%–80%, or the mass percentage of the first polymer in the polymer substrate is 50%–75%, or the mass percentage of the first polymer in the polymer substrate is 60%–75%; the mass percentage of the second polymer in the polymer substrate is 20%–60%, or the mass percentage of the second polymer in the polymer substrate is 25%–50%, or the mass percentage of the second polymer in the polymer substrate is 25%–40%.

[0096] For the battery cell of the embodiments of the present disclosure, the polymer matrix in the second slurry is a composite of multiple polymers, combining a high-elasticity body and a high-strength material. In this way, the content of the first polymer with a high elastic modulus is higher than that of the second polymer with a higher strength, so that the formed encapsulation structure has a sufficient elastic modulus and toughness, can provide sufficient expansion adaptability, resist external impacts and restrain expansion, and also has good flexibility, and can adapt to the overall expansion and contraction without cracking. The second polymer can endow the encapsulation structure with sufficient mechanical strength and thermal stability.

[0097] Optionally, the mass percentage of the first polymer in the polymer matrix is 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any value in the range of 50% to 80%.

[0098] Optionally, the mass percentage of the second polymer in the polymer matrix is 20%, 25%, 30%, 35%, 40%, 45%, 50%, or any value in the range of 20% to 60%.

[0099] In some embodiments, the solid content of the second slurry is 60% to 75%. The polymer matrix in the second slurry includes a first polymer and a second polymer. The first polymer includes polyisobutene, and the second polymer includes polyimide or polyphenylene ether. The mass percentage of polyisobutene in the polymer matrix is 60% to 75%, and the mass percentage of polyimide or polyphenylene ether in the polymer matrix is 25% to 40%. Polyisobutene provides expansion adaptability, and polyimide or polyphenylene ether endows mechanical strength and thermal stability. Polyisobutene has good flexibility, enabling the encapsulation structure to adapt to the slight expansion and contraction of the battery cell during charge and discharge, and avoiding cracking of the encapsulation structure 2 due to excessive rigidity. While polyimide or polyphenylene ether has relatively high strength and rigidity, providing good mechanical support for the encapsulation structure 2 and enhancing the stability of the encapsulation structure 2.

[0100] Optionally, in the second slurry, the mass percentage of the functional material in the dry solid content of the 3D printing overhang slurry is 5% to 40%, or the mass percentage of the functional material in the dry solid content of the 3D printing overhang slurry is 10% to 40%, or the mass percentage of the functional material in the dry solid content of the 3D printing overhang slurry is 10% to 35%, or the mass percentage of the functional material in the dry solid content of the 3D printing overhang slurry is 10% to 30%.

[0101] Optionally, the functional material in the second slurry includes a heat absorber. The mass percentage of the heat absorber in the functional material is 60% to 100%, or the mass percentage of the heat absorber in the functional material is 80% to 100%, or the mass percentage of the heat absorber in the functional material is 60% to 90%.

[0102] The second slurry has a high heat absorbent and can be disposed on the outer periphery of the battery cell structure to play an overall protective role. The second slurry contains a high content of heat absorbent, enabling the slurry to absorb a large amount of heat during the charging and discharging process of the battery cell, quickly reducing the surface temperature of the battery cell, and preventing safety problems such as thermal runaway caused by overheating of the battery cell. This is particularly important for battery cells with high power output and can ensure the stability of the battery cell during high-load operation.

[0103] Optionally, the functional material in the second slurry includes a heat absorbent, and the mass percentage of the heat absorbent in the functional material is 60%, 70%, 80%, 90%, 100% or any value within the range of 60% - 100%.

[0104] Optionally, the functional material in the second slurry includes a heat absorbent, and the heat absorbent includes polyethylene glycol or polyvinyl alcohol. Both polyethylene glycol and polyvinyl alcohol have a high specific heat capacity and good thermal conductivity, can quickly absorb the heat generated during the charging and discharging process of the battery cell, reduce the surface temperature of the battery cell, and prevent safety problems such as thermal runaway caused by overheating of the battery cell. Both polyethylene glycol and polyvinyl alcohol have a certain viscosity adjustment effect, can improve the rheological properties of the slurry, and make it more suitable for the requirements of 3D printing process. On the premise of ensuring the heat absorption performance, by adjusting the dosage of polyethylene glycol or polyvinyl alcohol, the viscosity and fluidity of the slurry can be adjusted to ensure that the slurry can uniformly cover the outer side surface of the battery cell during the printing process and form a complete coating layer.

[0105] Optionally, the functional material in the second slurry further includes a reinforcing agent, and the reinforcing agent includes hydrophobic fumed silica, which can improve the barrier property and wear resistance of the encapsulation structure.

[0106] Optionally, the functional material of the second slurry includes a reinforcing agent, and the mass percentage of the reinforcing agent in the functional material is 0 - 40%.

[0107] In some alternative embodiments, the mass percentage of the functional material in the second slurry in the dry solids content of the second slurry is 10% - 30%, the functional material includes high molecular weight polyethylene glycol or polyvinyl alcohol, and the mass percentage of high molecular weight polyethylene glycol or polyvinyl alcohol in the functional material is 60% - 100%. Optionally, the functional material further includes hydrophobic fumed silica, and the mass percentage of hydrophobic fumed silica in the functional material is 0 - 40%.

[0108] Combined Figure 11 As shown, the embodiments of the present disclosure provide a method for preparing a 3D printing overhang slurry, including the following steps: S110. Prepare each raw material for the 3D printed overhang slurry according to any of the foregoing embodiments. In this step S110, each raw material at least includes a polymer substrate, a solvent, and a functional material, and the functional material at least includes one or more of an oxygen adsorbent, a water adsorbent, and an endothermic agent. The dosage of each raw material meets the dosage of each raw material of the 3D printed overhang slurry according to any of the foregoing embodiments.

[0109] S120. Add the polymer substrate to the solvent and dissolve to obtain solution A; S130. Add the functional material to solution A to obtain the 3D printed overhang slurry.

[0110] In the method of the embodiment of the present disclosure, the polymer substrate is added to the solvent and dissolved to obtain solution A, so that the polymer chains in solution A are fully extended to form a three-dimensional network structure. Then the functional material is added to solution A, so that the functional material is wrapped by the three-dimensional network structure in solution A, improving the mixing uniformity and avoiding density differences. And the Brownian motion of the functional material in solution A is weakened, and the steric hindrance effect can inhibit agglomeration, ensuring the uniformity and particle size of the 3D printed overhang slurry. Optionally, in S120, the polymer substrate is slowly added to the solvent and placed in a magnetic stirrer for 4 h. After the polymer is completely dissolved, solution A is obtained to improve the solubility of the polymer substrate.

[0111] Optionally, in S130, after the functional material is added to solution A, it is stirred at a high speed for 1 h to obtain the 3D printed overhang slurry.

[0112] Combined with Figures 2 to 8 As shown, the embodiment of the present disclosure provides an electrode tab, and the electrode tab is a positive electrode tab 12 or a negative electrode tab 11. Among them, when the electrode tab includes the positive electrode tab 12, the positive electrode tab 12 includes an empty foil area, and the 3D printed overhang slurry is provided in the empty foil area. When the electrode tab includes the negative electrode tab 11, the negative electrode tab 11 includes an overhang area 111, and the 3D printed overhang slurry is provided in the overhang area 111 of the negative electrode tab 11. The electrode tab includes a combined negative electrode tab with the negative electrode tab 11 having solid electrolyte layers 13 provided on both of its side surfaces, and the 3D printed overhang slurry is provided on the surface of the solid electrolyte layer 13 of the combined negative electrode tab corresponding to the overhang area 111 of the negative electrode tab 11. Among them, the 3D printed overhang slurry is the 3D printed overhang slurry according to any of the foregoing embodiments or the 3D printed overhang slurry prepared by the preparation method of the 3D printed overhang slurry according to any of the foregoing embodiments.

[0113] In the embodiment of the present disclosure, a 3D printed overhang paste is disposed in a region corresponding to the overhang region 111 of the electrode tab. For example, in the empty foil region of the positive electrode tab 12, on the surface of the overhang region 111 of the negative electrode tab 11, or on the surface of the solid electrolyte layer corresponding to the overhang region 111 of the composite negative electrode tab, so that the 3D printed overhang paste is disposed in the overhang void of the cell obtained by lamination, and an overhang encapsulation structure 2 is obtained after curing.

[0114] The 3D printed overhang paste disposed on the electrode tab in the embodiment of the present disclosure can be printed and disposed by a 3D printing method.

[0115] The 3D printed overhang paste disposed on the electrode tab in the embodiment of the present disclosure can enter the subsequent process while remaining in a paste state; or the 3D printed overhang paste can be cured and then enter the subsequent process, which is not limited and is determined according to the actual situation.

[0116] In the cell of the embodiment of the present disclosure, the 3D printed overhang paste will obtain an encapsulation structure 2 after curing. Curing is a process of evaporating the solvent in the paste. Therefore, the curing temperature is determined according to the type of solvent used. Optionally, the temperature is 60°C to 150°C.

[0117] In some embodiments, the positive electrode tab 12 uses the positive electrode tab 12 in the electrode tab of any of the foregoing embodiments; or, the negative electrode tab 11 uses the negative electrode tab 11 in the electrode tab of any of the foregoing embodiments or a composite negative electrode tab.

[0118] The existing cell structure is as Figure 1 shown. The cell includes alternately stacked positive electrode tabs 12 and negative electrode tabs 11, and a solid electrolyte layer 13 is disposed between adjacent positive electrode tabs 12 and negative electrode tabs 11; at least one side of the negative electrode tab 11 extends beyond the positive electrode tab 12 in the circumferential direction to form an overhang region 111. The positive electrode tab 12 includes a positive current collector 122 and a positive active material layer 121 disposed on the positive current collector 122. The negative electrode tab 11 includes a negative current collector 113 and a negative active material layer 112 disposed on the negative current collector 113. The solid electrolyte layer 13 connects the negative active material layer 112 and the positive active material layer 121 to provide the function of lithium ion transmission.

[0119] An embodiment of the present disclosure provides an electric core, which includes a stacked structure 10 and a packaging structure 2. The stacked structure 10 includes alternately stacked positive electrode sheets 12 and negative electrode sheets 11, and a solid electrolyte layer 13 is disposed between adjacent positive electrode sheets 12 and negative electrode sheets 11; at least one side of the negative electrode sheet 11 in the circumferential direction extends beyond the positive electrode sheet 12 to form an overhang region 111; wherein, a packaging structure 2 is disposed in the overhanging void region corresponding to the overhang region 111; wherein, the packaging structure 2 is obtained by 3D printing an overhang slurry in the overhanging void region; the 3D printing overhang slurry is the 3D printing overhang slurry of any of the foregoing embodiments or the 3D printing overhang slurry prepared by the preparation method of the 3D printing overhang slurry of any of the foregoing embodiments.

[0120] The electric core in the embodiment of the present disclosure includes the 3D printing overhang slurry of any of the foregoing embodiments, and the electric core has all the technical effects of the 3D printing overhang slurry, which will not be elaborated here.

[0121] Optionally, the packaging structure 2 includes a connected filling portion 21 and a covering portion 22. At least part of the filling portion 21 is located in the overhanging void region, and the covering portion 22 covers the circumferential side surface of the stacked structure 10.

[0122] In the embodiment of the present disclosure, the overhanging void region is the overhanging void region (i.e., the overhang void) corresponding to the overhang region 111 formed by at least one side of the negative electrode sheet 11 in the circumferential direction extending beyond the positive electrode sheet 12. In this case, the negative electrode sheet 11 is designed to be larger than the positive electrode sheet 12, so that at least one side of the negative electrode sheet 11 in the circumferential direction extends beyond the positive electrode sheet 12 to form an overhang region 111. Relative to the circumferential outer contour of the stacked structure 10, the overhanging void region extends inwardly of the stacked structure 10 and has a certain depth (see the depth d1 shown in Figure 10 ), and stress concentration is likely to occur under the forming pressure during the assembly of the solid-state battery, resulting in a short circuit problem of the electric core, thereby reducing the manufacturing yield and performance consistency of the electric core. The filling portion 21 of the packaging structure 2 fills the overhanging void region, thereby being able to solve the problem that stress concentration is likely to occur in these overhanging void regions under the forming pressure, resulting in a short circuit of the electric core.

[0123] The wrapping part 22 of the encapsulation structure 2 compensates for defects left over from previous process steps such as defects at the edges of the electrode tabs, burrs on the foil, and misalignment of the stacked sheets by wrapping around the peripheral end faces of the battery cell. Moreover, the fully enclosed outer frame encapsulation design not only protects the internal environment of the battery cell but also accommodates the volume changes during the operation of the battery cell, comprehensively improving the yield of battery cell manufacturing and the safety performance of the battery cell. For example, the wrapping part 22 can wrap the burrs on the negative current collector 113, the defects at the edges of the electrode tabs, as well as the misaligned protrusions and depressions generated when the stacked sheets are misaligned. Burrs are extremely likely to pierce the solid electrolyte layer, resulting in micro-shorts between the positive and negative electrodes, causing self-discharge of the battery and deterioration of the electrochemical performance; in terms of safety, the local current density at the micro-short exceeds 100 A / cm 2 (far exceeding 1 - 5 A / cm 2 during normal charge and discharge), which will quickly accumulate heat and may cause thermal runaway of the battery in severe cases.

[0124] Optionally, the filling part 21 includes a support part 211 and a penetration part 212. The support part 211 is located in the overhanging void area, and the penetration part 212 is the part that extends from the support part 211 and penetrates into the interior of the sheet layer surrounding the overhanging void area; the penetration depth of the penetration part 212 is greater than or equal to 1 μm.

[0125] In the battery cell of the embodiment of the present disclosure, in addition to the support part 211 disposed in the overhanging void area, the encapsulation structure 2 further includes a penetration part 212 that penetrates into the sheet layer surrounding the overhanging void area. The setting of the penetration part 212 ensures the interfacial bonding effect between the encapsulation structure 2 and the sheet layer of the stacked sheet structure 10, improves the bonding strength between the encapsulation structure 2 and the sheet layer, and the penetration part 212 penetrates into the active material area of the electrode tab to enhance the cohesive force and has a certain deformation ability to adapt to the forming pressure of the stacked battery cell and the volume changes of the active material (including volume changes caused by the forming pressure and charge and discharge), avoiding the detachment of the encapsulation structure 2 from the sheet layer (electrode tab and / or solid electrolyte layer 13) and excessive deformation resulting in the generation of new edge stresses, thereby improving the performance of the solid-state battery.

[0126] In the battery cell of the embodiment of the present disclosure, the bonding strength between the encapsulation structure 2 and the sheet layer of the stacked sheet structure 10 reaches 1.2 MPa or more. The first-cycle discharge specific capacity of the solid-state battery obtained by assembling the battery cells of the embodiment of the present disclosure can be improved.

[0127] In the battery cell of the embodiment of the present disclosure, "inside the sheet layer" refers to the inside of the positive electrode tab 12, the negative electrode tab 11, and the solid electrolyte layer 13, and more specifically, the positive active material layer 121, the negative active material layer 112, and the solid electrolyte layer 13.

[0128] In the battery cell of the embodiments of the present disclosure, the filling rate of the encapsulation structure 2 for the overhang void area is greater than or equal to 60%. Optionally, the filling rate is greater than or equal to 70%. Optionally, the filling rate is greater than or equal to 80%. Optionally, the filling rate is greater than or equal to 90%.

[0129] The battery cell of the embodiments of the present disclosure is a stacked battery cell and can be used as the battery cell of a solid-state battery. Optionally, the stacking structure 10 includes one or more stacking units, and each stacking unit includes a negative electrode tab 11, a solid electrolyte layer 13, and a positive electrode tab 12 stacked in sequence. When the stacking structure 10 includes multiple stacking units, the positive electrode tab 12 of one stacking unit and the negative electrode tab 11 of an adjacent stacking unit are stacked through the solid electrolyte layer 13. That is, the stacking structure 10 is arranged and stacked in the manner of negative electrode tab 11 / solid electrolyte layer 13 / positive electrode tab 12 / solid electrolyte layer 13 / negative electrode tab 11 / solid electrolyte layer 13 / positive electrode tab 12 / .... Generally, the electrode tabs on the two surfaces of the stacking structure 10 are negative electrode tabs 11, but this is not limited thereto.

[0130] The penetration part 212 of the encapsulation structure 2 penetrates into the layers around the overhang void area of the stacking structure 10. For example, the penetration part 212 penetrates into the active material of the positive electrode tab 12, the solid electrolyte layer 13, and the active material of the negative electrode tab 11 around the overhang void area. Therefore, theoretically, the 3D printing overhang slurry penetrating into the layers may cause the positive electrode tab 12 to lose part of its theoretical capacity. However, in practical applications, the setting of the penetration part 212 can not only improve the bonding strength between the encapsulation structure 2 and the stacking structure 10, improve the yield of the battery cell, but also greatly improve the actual capacity of the battery cell, improve the first-cycle specific capacity and cycle performance of the battery, and thus improve the battery performance.

[0131] In some embodiments, such as Figure 10As shown, the penetration depth d2 of the penetration part 212 is greater than or equal to 1 μm. By controlling the penetration depth, the theoretical capacity loss is balanced with the actual capacity improvement, ensuring that the battery performance can be improved. Optionally, the penetration depth of the penetration part 212 is greater than or equal to 1 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part 212 is greater than or equal to 10 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part 212 is greater than or equal to 50 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part 212 is greater than or equal to 100 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part 212 is greater than or equal to 150 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part 212 is greater than or equal to 200 μm and less than or equal to 250 μm. By controlling the penetration depth of the penetration part 212, the theoretical capacity loss is controlled, and while ensuring the bonding strength to provide a high cell yield, the battery performance can be better improved.

[0132] In some embodiments, the penetration percentage of the penetration area of the penetration part 212 in the area of the electrode tab is less than or equal to 1%. In this embodiment, by controlling the penetration percentage of the penetration part 212, the theoretical capacity loss is balanced with the actual capacity improvement, ensuring that the battery performance can be improved. Optionally, the penetration percentage of the penetration area of the penetration part 212 in the area of the electrode tab is less than or equal to 0.8%.

[0133] Optionally, the penetration depth d2 of the penetration part 212 is less than or equal to 300 μm, and the penetration percentage of the penetration area of the penetration part 212 in the area of the electrode tab is less than or equal to 1%.

[0134] The cell of the embodiment of the present disclosure is more suitable for large-sized cells. It can be understood that the larger the cell size, the smaller the ratio of the penetration depth / penetration area of the penetration part 212 to the area of the electrode tab, and the smaller the theoretical capacity loss. However, the bonding strength between the encapsulation structure 2 and the stacked structure 10 is not affected. While the cell yield is improved, the actual capacity of the cell capacity can be greatly improved, the first-cycle specific capacity and cycle performance of the battery can be improved, and thus the battery performance can be improved.

[0135] Optionally, as Figure 2 and Figure 9As shown, when the encapsulation structure 2 includes a connected filling part 21 and a covering part 22, and the filling part 21 includes a supporting part 211 and a permeating part 212, the supporting part 211 and the permeating part 212 are made of the same material, and the covering part 22 is made of a material different from that of the filling part 21. The filling part 21 needs to be filled into the overhang void area and a 3D printing overhang paste with a certain permeability is required to ensure that the 3D printing overhang paste can enter the overhang void area and penetrate into the sheet layer. The covering part 22 covers the circumferential side surface of the stacked sheet structure 10, and a 3D printing overhang paste without permeability can be used.

[0136] Optionally, the filling part is formed by a first paste, and the covering part is formed by a second paste. The solid content of the first paste is less than or equal to the solid content of the second paste.

[0137] In the battery cell of the embodiment of the present disclosure, when the filling part is formed by the first paste, the solid content of the first paste is small, which can ensure the fluidity and wettability of the 3D printing overhang paste, so that the filling part 21 can penetrate into the overhang void area and even into the inside of the sheet layer, and can also take into account the mechanical strength, provide sufficient support stress, and improve the filling effect. The covering part uses the second paste with a higher solid content to form a rigid, tough and dense thick coating on the circumferential side surface of the stacked sheet structure 10, which can better seal the edge of the electrode sheet or the bonding of the diaphragm end face, etc., cover the circumferential side surface of the battery cell, improve the sealing effect of the battery cell, and isolate oxygen, water, etc. in the external environment. Improve the safety performance of the battery cell.

[0138] The filling part of the embodiment of the present disclosure uses the first paste. The polymer base of the first paste includes one or more of polyvinylidene fluoride, polyacrylonitrile, and polyethylene oxide, so that the filling part 21 has a certain elastic modulus and viscoelasticity, can provide flexible support and stress buffering, and avoid the fracture of the supporting part 211.

[0139] In some embodiments, when the filling portion is formed from the first slurry, the solid content of the first slurry is 35% to 60%, and the polymer base in the first slurry includes one or more of polyvinylidene fluoride, polyacrylonitrile, and polyethylene oxide. Such a solid content of 35% to 60% enables the filling portion 21, especially the permeating portion 212, to have good fluidity, which can not only fill the overhanging void area but also penetrate into the interior of the sheet layer, improving the bonding strength between the encapsulation structure 2 and the stacked sheet structure 10. Additionally, the first slurry uses one or more of polyvinylidene fluoride, polyacrylonitrile, and polyethylene oxide, which endows the filling portion 21 with a certain elasticity. This not only enables the supporting portion 211 to have a certain deformation ability but also enables the permeating portion 212 to have a certain deformation ability, improving the cohesion force. This can solve the problem of uneven stress caused by overhang, ensure the interface stability between the electrode and the solid electrolyte, thereby reducing the occurrence of short circuits, and further adapting to the forming pressure of the stacked battery cell and the volume change of the active material, avoiding the detachment of the encapsulation structure 2 from the sheet layer and excessive deformation that may lead to the generation of new edge stresses, thus enhancing the performance of the solid-state battery.

[0140] Optionally, when the filling portion is formed from the first slurry, the functional materials in the first slurry include multiple types of oxygen adsorbents, water adsorbents, and heat absorbers. The functional materials enable the filling portion 21 not only to support the overhanging area 111 but also to regulate the microenvironment inside the battery cell, reducing side reactions in the solid-state battery and improving the thermal stability of the solid-state battery. Since the filling portion 21 is located inside the stacked sheet structure 10 and can even penetrate between the sheet layers, one or more of oxygen adsorbents, water adsorbents, and heat absorbers can be added to the filling portion 21 to synergistically regulate the environment inside the battery cell. The water adsorbent can efficiently capture the residual moisture inside the battery cell. The oxygen adsorbent can inhibit oxidation side reactions inside the battery cell, while the heat absorber can absorb local hot spots, thereby regulating the environment inside the battery cell. While solving the stress problem caused by the overhanging area 111, it further improves the performance and safety of the solid-state battery.

[0141] Optionally, when the filling portion is formed from the first slurry, the water adsorbent in the first slurry includes zeolite. Zeolite has a low cost, strong adsorption, and high adsorption capacity. Zeolite can be well compatible with various polymer bases, uniformly dispersed in the slurry, forming a stable system without problems such as delamination and precipitation, ensuring the uniformity and consistency of the slurry. It can also work synergistically with other functional materials such as oxygen adsorbents and heat absorbers to jointly perform multiple functions such as adsorbing moisture, oxygen, and heat, achieving comprehensive optimization of the slurry performance.

[0142] In some alternative embodiments, when the filling portion is formed of the first slurry, the functional materials include zeolite, polydopamine nanoparticles, and an endothermic agent. Among them, the mass percentage of zeolite in the functional materials is 30–60% to efficiently capture residual moisture; the mass percentage of polydopamine nanoparticles in the functional materials is 20–50% to effectively inhibit oxidation side reactions; and the mass percentage of polyethylene glycol in the functional materials is 20–40% to absorb local hot spots.

[0143] The coating portion of the embodiments of the present disclosure is formed of the second slurry. The polymer substrate in the second slurry is a composite of multiple polymers, combining a high-elasticity body and a high-strength material. In this way, the content of the first polymer with a high elastic modulus is higher than that of the second polymer with a higher strength, so that the coating portion 22 has sufficient elastic modulus and toughness, can provide sufficient expansion adaptability, resist external impacts and restrain expansion, and also has good flexibility to adapt to the overall expansion and contraction without cracking. The second polymer can endow the coating portion 22 with sufficient mechanical strength and thermal stability.

[0144] In some embodiments, when the coating portion is formed of the second slurry, the solid content of the second slurry is 60%–75%. The polymer substrate in the second slurry includes a first polymer and a second polymer. The first polymer includes polyisobutene, and the second polymer includes polyimide or polyphenylene ether. The mass percentage of polyisobutene in the polymer substrate is 60%–75%, and the mass percentage of polyimide or polyphenylene ether in the polymer substrate is 25%–40%. Polyisobutene provides expansion adaptability, and polyimide or polyphenylene ether endows mechanical strength and thermal stability. Polyisobutene has good flexibility, enabling the coating portion 22 to adapt to the slight expansion and contraction of the battery cell during charging and discharging, and avoiding cracking of the encapsulation structure 2 due to excessive rigidity. Polyimide or polyphenylene ether has relatively high strength and rigidity, providing good mechanical support for the coating portion 22 and enhancing the stability of the encapsulation structure 2.

[0145] Optionally, when the coating portion is formed of the second slurry, the functional material in the second slurry includes an endothermic agent, and the mass percentage of the endothermic agent in the functional material is 60%, 70%, 80%, 90%, 100% or any value within the range of 60%–100%.

[0146] Optionally, when the coating part is formed from the second slurry, the functional material in the second slurry includes a heat absorber, and the heat absorber includes polyethylene glycol or polyvinyl alcohol. Both polyethylene glycol and polyvinyl alcohol have a high specific heat capacity and good thermal conductivity, can quickly absorb the heat generated by the battery cell during charge and discharge, reduce the surface temperature of the battery cell, and prevent safety problems such as thermal runaway caused by overheating of the battery cell. Both polyethylene glycol and polyvinyl alcohol have a certain viscosity regulating effect, can improve the rheological properties of the slurry, and make it more suitable for the requirements of the 3D printing process. On the premise of ensuring the heat absorption performance, by adjusting the dosage of polyethylene glycol or polyvinyl alcohol, the viscosity and fluidity of the slurry can be adjusted to ensure that the slurry can evenly cover the circumferential side of the battery cell during printing to form a complete coating layer.

[0147] Optionally, when the coating part is formed from the second slurry, the functional material in the second slurry further includes a reinforcing agent, and the reinforcing agent includes hydrophobic fumed silica, which can improve the barrier property and wear resistance of the coating part 22.

[0148] In some alternative embodiments, when the coating part is formed from the second slurry, the mass percentage of the functional material in the second slurry in the dry solid content of the second slurry is 10% - 30%, the functional material includes high molecular weight polyethylene glycol or polyvinyl alcohol, and the mass percentage of high molecular weight polyethylene glycol or polyvinyl alcohol in the functional material is 60% - 100%. Optionally, the functional material further includes hydrophobic fumed silica, and the mass percentage of hydrophobic fumed silica in the functional material is 0 - 40%.

[0149] It can be understood that the filling part 21 and the coating part 22 of the encapsulation structure 2 can also adopt any components and ratios in the above-mentioned 3D printing overhang slurry, and the components and ratios in the 3D printing overhang slurry can be adjusted according to different battery materials and types in practical applications.

[0150] Optionally, the positive electrode plate 12 includes a positive electrode current collector 122 and a positive electrode active material layer 121 provided on the positive electrode current collector 122. Among them, one or both sides of the positive electrode current collector 122 are covered with the positive electrode active material layer 121, which is determined according to actual needs.

[0151] In this embodiment, the positive electrode current collector 122 is usually composed of a metal material. Optionally, the material of the positive electrode current collector 122 includes aluminum foil. The thickness of the positive electrode current collector 122 can be controlled within 6 - 20 μm. Optionally, the thickness of the positive electrode current collector 122 is 10 - 20 μm. Optionally, the positive electrode current collector 122 includes an aluminum foil with a thickness of 10 - 20 μm.

[0152] Optionally, the positive electrode active material layer 121 includes a positive electrode active paste, which is mainly composed of one or more composites of lithium iron phosphate, lithium cobaltate, lithium manganate, lithium vanadate, lithium nickelate, lithium manganese oxide, lithium nickel manganate, lithium-rich manganese-based, lithium manganese iron phosphate, lithium nickel cobalt aluminate, lithium nickel cobalt manganate, lithium iron phosphate, lithium vanadium phosphate, sulfur, lithium sulfide, and sulfur iodide.

[0153] Optionally, the negative electrode sheet 11 includes a negative electrode current collector 113 and a negative electrode active material layer 112 provided on the negative electrode current collector 113. The negative electrode active material layer 112 includes a negative electrode active paste, which is determined according to actual requirements.

[0154] In this embodiment, the negative electrode current collector 113 is usually made of a metal material. Optionally, the material of the negative electrode current collector 113 includes copper foil. The thickness of the negative electrode current collector 113 can be controlled within 6 - 10 μm. Optionally, the thickness of the negative electrode current collector 113 is 6 - 8 μm. Optionally, the negative electrode current collector 113 includes a copper foil with a thickness of 6 - 10 μm.

[0155] Optionally, the negative electrode active material layer 112 is not limited and is determined according to actual requirements. Optionally, the negative electrode active material layer 112 includes a negative electrode active material and other additive substances. The other additive substances include one or more composites of components such as pure silicon materials, graphite materials, carbon materials, silicon-carbon materials, and silicon-oxygen materials.

[0156] Optionally, a negative electrode sheet includes a negative electrode active material layer 112. That is, the negative electrode sheet of this embodiment is only composed of the negative electrode active material layer 112. The negative electrode active material layer 112 is designed to reversibly accommodate and release lithium ions and can play the role of external conduction, and no longer requires the negative electrode current collector 113 to provide a conduction function. At this time, the negative electrode active material layer 112 is composed of one or more composites of conductive materials such as lithium metal and carbon materials.

[0157] Optionally, the negative electrode sheet 11 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 hybrid 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.

[0158] In the battery cell of the present disclosure embodiment, the solid electrolyte layer 13 connects the negative electrode active material layer 112 and the positive electrode active material layer 121 to each other and provides the function of lithium ion transmission. The solid electrolyte layer 13 is obtained by compounding one or more of components such as sulfide electrolytes, oxide electrolytes, polymer electrolytes, and halide electrolytes.

[0159] Preferably, the solid electrolyte layer 13 comprises a sulfide electrolyte, and the sulfide electrolyte comprises one or more of lithium phosphorus chlorine sulfur, lithium phosphorus bromine sulfur, lithium phosphorus iodine sulfur, lithium phosphorus silicon sulfur, lithium phosphorus aluminum sulfur, lithium phosphorus germanium sulfur, lithium phosphorus boron sulfur, lithium phosphorus sulfur, lithium silicon sulfur, and lithium silicon indium sulfur.

[0160] Optionally, the width of the filling portion 21 is smaller than the width of the overhang region 111. Optionally, the width of the filling portion 21 is 1 mm to 2 mm.

[0161] Combined Figure 12 As shown, an embodiment of the present disclosure provides a method for preparing an electric core, including the following steps: S210. Prepare a positive electrode sheet 12, a negative electrode sheet, and a solid electrolyte layer 13; wherein, the size of the negative electrode sheet is at least larger than the size of the positive electrode sheet 12 on at least one circumferential side, so that the negative electrode sheet has an overhang region 111; wherein, the positive electrode sheet 12 adopts the positive electrode sheet 12 of any one of the foregoing embodiments, or the negative electrode sheet adopts the negative electrode sheet 11 or the combined negative electrode sheet of any one of the foregoing embodiments.

[0162] S220. Stack the positive electrode sheet 12 and the negative electrode sheet alternately, and a solid electrolyte layer 13 is disposed between adjacent positive electrode sheets 12 and negative electrode sheets to obtain an electric core; wherein, a cured 3D printed overhang paste is disposed at the overhang gap of the electric core.

[0163] Optionally, in step S210, preparing the positive electrode sheet 12 includes: disposing a positive electrode active paste on the positive electrode current collector 122 to obtain a positive electrode active material layer 121, and leaving an empty foil area on the positive electrode current collector 122 around the positive electrode active material layer 121; printing and disposing a 3D printed overhang paste on the empty foil area of the positive electrode sheet 12 by a 3D printing method to obtain the positive electrode sheet 12.

[0164] Optionally, in step S210, preparing the negative electrode sheet includes: disposing a negative electrode active paste on the negative electrode current collector 113 to obtain a negative electrode active material layer 112, and obtaining the negative electrode sheet by printing and disposing a 3D printed overhang paste on the surface of the overhang region 111 of the negative electrode sheet by a 3D printing method.

[0165] Optionally, in step S210, it further includes: transferring the solid electrolyte layer 13 to both surfaces of the negative electrode sheet, and printing and disposing a 3D printed overhang paste on the surface of the solid electrolyte layer corresponding to the overhang region 111 of the negative electrode sheet by a 3D printing method to obtain a combined negative electrode sheet.

[0166] Optionally, before the positive electrode sheet 12 and the negative electrode sheet are alternately stacked in step S220, it further includes: performing 3D printing on the positive electrode sheet 12 or the negative electrode sheet with a first slurry, and curing the first slurry provided on the positive electrode sheet 12 or the negative electrode sheet to obtain a positive electrode sheet 12 or a negative electrode sheet having a filling portion 21. Alternatively, after the positive electrode sheet 12 and the negative electrode sheet are alternately stacked in step S220, it further includes: curing the stacked laminated battery cell structure to obtain a battery cell having a packaging structure 2. It is determined according to the actual situation.

[0167] Optionally, after obtaining the positive electrode sheet 12 or the negative electrode sheet having the filling portion 21 in step S220, it further includes: performing 3D printing on the circumferential side surface of the battery cell with a second slurry, and curing the second slurry to form a coating portion, and the coating portion is connected to the filling portion.

[0168] First, the first slurry is printed onto the positive electrode sheet or the negative electrode sheet to form the filling portion to support the overhang region, and the functional materials added in the filling portion can adjust the internal environment of the battery cell, such as adsorbing oxygen, water, heat, etc., to improve the stability and safety of the battery. Then, the positive electrode sheet, the negative electrode sheet, and the solid electrolyte layer are alternately stacked to form a battery cell, and then a second slurry is provided on the outer circumference of the battery cell by 3D printing to form a coating portion. In this way, the coating portion can not only coat the battery cell from the outside to make up for the defects left in the previous process sections such as the edge defects of the electrode sheet, burrs of the foil, and misalignment of the laminations, but also the fully enclosed outer frame packaging design can protect the internal environment of the battery cell and accommodate the volume change during the operation of the battery cell, comprehensively improving the yield of battery cell manufacturing and the safety performance of the battery cell.

[0169] Combined Figure 13 As shown, the embodiments of the present disclosure also provide another method for preparing a battery cell, including the following steps: S310. Stack the positive electrode sheet, the solid electrolyte layer, the negative electrode sheet, and the solid electrolyte layer in this order to obtain a stacked structure; wherein, a hanging void area is formed on the circumferential side surface of the stacked structure.

[0170] S320. Set 3D printing overhang slurry into the hanging void area of the stacked structure to obtain a battery cell having a packaging structure.

[0171] In the method for preparing an electric core according to an embodiment of the present disclosure, first, a positive electrode sheet, a negative electrode sheet, and a solid electrolyte layer are stacked in a specific order to obtain a stacked sheet structure, and then a 3D printing overhang paste is disposed in the hanging void area of the stacked sheet structure. The method for preparing an electric core according to an embodiment of the present disclosure is more practical. It can use a continuously coated electrode sheet, and is compatible with the overhang design and size equal design of the positive electrode sheet and the negative electrode sheet. It can simplify the short-circuit prevention treatment of the edge of a single electrode sheet into the edge short-circuit prevention encapsulation of the stacked sheet structure, greatly reducing the battery manufacturing process difficulty, cycle, and cost.

[0172] In the method for preparing an electric core according to an embodiment of the present disclosure, in step S310, the positive electrode sheet, the solid electrolyte layer, and the negative electrode sheet can each be obtained by a conventional method, which is not limited herein. Among them, the sizes of the positive electrode sheet and the negative electrode sheet can be an equal-size design, or an overhang design in which at least one side of the circumferential direction of the negative electrode sheet is larger than that of the positive electrode sheet.

[0173] In step S320, the manner of disposing the 3D printing overhang paste in the hanging void area of the stacked sheet structure is not limited, as long as the encapsulation paste can be disposed in the hanging void area and penetrate into the surrounding sheet layers. In some embodiments, disposing the 3D printing overhang paste in the hanging void area of the stacked sheet structure includes: using a 3D printing method to dispose the 3D printing overhang paste in the hanging void area of the stacked sheet structure.

[0174] Optionally, a 3D printing method is used to print and dispose the 3D printing overhang paste in the hanging void area of the stacked sheet structure. Compared with other methods, the edge encapsulation of the electric core of the stacked solid-state battery by 3D printing technology can accurately control the amount of deposited material. When introducing the 3D printing overhang paste into the circumferential side surface and the hanging void area of the stacked sheet structure, an appropriate amount of the 3D printing overhang paste can be accurately delivered according to the requirements of different positions. At the same time, the non-contact 3D printing manufacturing technology will not cause mechanical damage to the electrode sheet. Moreover, the 3D printing method can construct a support structure in a micron-level gap, so as to effectively ensure the filling rate of the interlayer voids and enable the 3D printing overhang paste to penetrate deep into the hanging void area and penetrate into the surrounding sheet layers, thereby more effectively solving the edge stress concentration problem during the pressurized manufacturing or high-voltage operation of the solid-state electric core. Moreover, the 3D printing method has high processing efficiency and high material utilization rate, and can take into account the permeability and anti-overflow problems of the fluid 3D printing overhang paste during the printing process. In the embodiment of the present disclosure, the printing path and printing parameters are set according to the actual situation in the 3D printing method, which is not limited.

[0175] In some embodiments, in step S320, setting the 3D printing overhang slurry in the overhang void area of the laminated structure includes: setting a first slurry in the overhang void area of the laminated structure to obtain a first laminated structure having a filling portion; setting a second slurry in the overhang void area of the first laminated structure to form a coating portion outside the filling portion and obtain an electric core having a packaging structure; wherein, the outer surface of the coating portion is flush with the peripheral side surface of the laminated structure, or the coating portion protrudes from the peripheral side surface of the laminated structure and coats the peripheral side surface of the laminated structure.

[0176] In the method for preparing the electric core of this embodiment, first, the first slurry is filled and set, so that the first slurry can penetrate into the peripheral layers of the overhang void area, and then the second slurry is used to completely fill the overhang void area, thereby being able to controllably control the depth of the 3D printing overhang slurry penetrating into the layers, ensuring both the interfacial bonding effect of deep penetration and avoiding the edge overflow defect, and forming a dense and pore-free packaging structure.

[0177] In one example, a 3D printing device is used to set the 3D printing overhang slurry in the void area of the laminated structure by a 3D printing method for a dynamic control preparation method. Among them, the 3D printing device can be a 3D printing device including one discharge head (for example, a single-nozzle 3D printing device) or multiple discharge heads (for example, a multi-nozzle 3D printing device). Optionally, a multi-nozzle 3D printing device is used to set the 3D printing overhang slurry in the overhang void area of the laminated structure for dynamic control packaging, wherein the first discharge head (the first printing head) is used to output the first slurry, and the second discharge head (the second printing head) is used to output the second slurry. During the 3D printing process, the printing path and printing parameters (such as printing speed, layer height, line width, print head aperture, etc.) are determined according to the depth and width of the overhang void area and the actual situation of the 3D printing overhang slurry, and are not limited. For example, the printing speed is 25 - 45 mm / s, the layer height is 10μm - 30μm, and the line width is 80 - 120μm. In the 3D dynamic control preparation method of this embodiment, the printing paths of the first slurry and the second slurry can be the same or different. Optionally, the printing path of the first slurry is a loop trajectory, and the printing path of the second slurry is a straight line trajectory.

[0178] In some embodiments, in step S320, after "setting 3D printing overhang slurry in the overhang void area of the laminated structure", the following steps are further included: a step of thermally pressing the laminated structure with the 3D printing overhang slurry set thereon. In this embodiment, the laminated structure with the 3D printing overhang slurry set thereon is thermally pressed to strengthen the bonding between the 3D printing overhang slurry and the cavity at the edge of the electrode tab, refill the microscopic depressions (such as cracks less than 5 μm) on the surface of the electrode tab, and reduce the interfacial void ratio; at the same time, by adding this thermal pressing step, the contact of each solid-solid interface in the battery cell can be improved, and the problem of lithium dendrite growth can be alleviated and the ion transport path can be shortened by repairing the poor contact interface. The thermal pressing treatment in this embodiment can be defined as a secondary curing treatment.

[0179] Optionally, thermally pressing the laminated structure with the 3D printing overhang slurry set thereon includes: placing the laminated structure with the 3D printing overhang slurry set thereon on a heating plate at a first preset temperature and treating for a first preset time. The thermal pressing treatment in this embodiment is denoted as the first type of thermal pressing treatment, where the pressure is the self-pressure of the laminated structure with the 3D printing overhang slurry set thereon.

[0180] Optionally, thermally pressing the laminated structure with the 3D printing overhang slurry set thereon includes: placing the laminated structure with the 3D printing overhang slurry set thereon on a heating plate at a first preset temperature and applying vibration, and treating for a second preset time. The thermal pressing treatment in this embodiment is denoted as the second type of thermal pressing treatment.

[0181] Optionally, thermally pressing the laminated structure with the 3D printing overhang slurry set thereon includes: placing the laminated structure with the 3D printing overhang slurry set thereon on a heating plate at a first preset temperature and applying pressure, and treating for a second preset time. The thermal pressing treatment in this embodiment is denoted as the third type of thermal pressing treatment.

[0182] Optionally, thermally pressing the laminated structure with the 3D printing overhang slurry set thereon includes: placing the laminated structure with the 3D printing overhang slurry set thereon on a heating plate at a first preset temperature and applying pressure and vibration, and treating for a second preset time. The thermal pressing treatment in this embodiment is denoted as the fourth type of thermal pressing treatment.

[0183] In the first hot pressing process to the fourth hot pressing process, the first preset temperature can make the 3D printed overhang slurry soften again to have a certain fluidity. It can be understood that a heating groove is provided on the heating plate, and the groove body of the heating groove is consistent with the outer contour of the stacked structure provided with the 3D printed overhang slurry. The stacked structure provided with the 3D printed overhang slurry is placed in the heating groove, then the inner wall of the heating groove can define the stacked structure, that is, it can avoid the slippage and dislocation of the laminas when pressure is applied, and can also avoid the 3D printed overhang slurry softened by reheating from flowing out of the lamina gap. Optionally, the first preset temperature is greater than or equal to Tmin and less than or equal to T′, T′ = Tm in +δ×(T max -T min )), where T max is the upper limit value of the melting point range of the 3D printed overhang slurry, T min is the lower limit value of the melting point range of the 3D printed overhang slurry, and the value range of δ is [0, 1 / 3]. The specific value of δ is determined according to the melting point range of the 3D printed overhang slurry, that is, the first preset temperature is the lower limit value of the melting point range of the 3D printed overhang slurry or a certain temperature higher than the lower limit value, which can make the 3D printed overhang slurry soften to have a certain fluidity. Optionally, δ is 0, 1 / 5, 1 / 4 or 1 / 3, etc.

[0184] Optionally, the first preset temperature is 60°C to 70°C. Optionally, the first preset temperature is 60°C.

[0185] Optionally, the first preset time is 20s to 60s. Optionally, the first preset time is 20s to 50s. The first preset time is 20s to 40s. The first preset time is 30s.

[0186] Optionally, the hot pressing treatment of the stacked structure provided with the 3D printed overhang slurry includes: applying a low pressure of 0.3 to 0.5 MPa and a low-frequency vibration of 20 Hz to 50 Hz to the stacked structure provided with the 3D printed overhang slurry for the first preset time, and then boosting the pressure to a high pressure of 1 to 3 MPa and a high-frequency vibration of 500 Hz to 2000 Hz for the first preset time.

[0187] In one example, as Figure 14 shown, a 3D printing control preparation method includes: S410. Stack the positive electrode plate, solid electrolyte layer, negative electrode plate and solid electrolyte layer in this order to obtain a stacked structure; wherein, a hanging void area is formed on the peripheral side surface of the stacked structure.

[0188] S420. Vertically set the laminated structure in the printing area of the 3D printing device with the side to be printed facing up. S430. Obtain the contour solid data of the side to be printed of the laminated structure; obtain the contour 3D model based on the contour solid data; perform slicing processing on the contour 3D model, conduct path planning and printing parameter design to obtain printing information. S440. The 3D printing device prints the 3D printing overhang slurry on the side to be printed according to the printing information, completing the encapsulation printing of the side to be printed of the laminated structure and obtaining a laminated structure with the 3D printing overhang slurry set thereon.

[0189] In this embodiment, the side to be printed of the laminated structure is one of the peripheral sides of the laminated structure. Repeat the above steps to perform encapsulation printing on each side one by one to complete the encapsulation of the laminated structure.

[0190] In step S430 of this embodiment, the solid contour data of the side to be printed includes data of key structural nodes such as the edge, layers, and overhang void area that can reflect the side to be printed. Optionally, obtaining the solid contour data of the side to be printed of the laminated structure includes: scanning the side to be printed of the laminated structure with a high-precision vision scanner or a 3D scanner, and at the same time combining the solid parameters of the laminated structure to obtain the solid contour data of the side to be printed. Among them, the solid parameters of the laminated structure include the size of the laminated structure, the number of laminated layers, etc. The side of the laminated structure is not a flat surface and has an overhang void area. Therefore, the solid contour data includes 3D solid data.

[0191] In step S430, obtaining the contour 3D model based on the contour solid data includes: importing the solid contour data of the side to be printed into 3D modeling software and performing modeling to obtain the contour 3D model. The 3D modeling software is not limited. For example, MeshLab, Blender, etc. During the modeling process, the solid contour data can be processed, including removing noise, filling holes, optimizing the mesh, etc., which is not limited.

[0192] Optionally, in step S430, the contour 3D model is sliced by slicing software. Among them, the slicing software generates printing information according to the shape, size, and printing parameters of the model. The printing parameters include printing layer height, filling density, printing speed, print head temperature, printing bed temperature, etc. The printing information includes the printing path and printing parameters. The printing path determines the movement trajectory of the print head. The printing parameters include printing speed, extrusion amount of the material, printing layer height, material heating temperature, print head temperature, etc. Among them, the printing path is output in the form of G-code instructions that can be recognized by the 3D printing device.

[0193] Optionally, the slicing software includes Cura, PrusaSlicer, etc.

[0194] It can be understood that the circumferential side surface of the stacked sheet structure includes four side surfaces in different directions, and each side surface is a side surface to be encapsulated.

[0195] Optionally, if the solid contour data of the side surface to be printed obtained in step 430 is the solid contour data of the side surface to be printed that is currently facing up in step S420, then the printing path obtained in step S430 is the printing path of the side surface to be printed that is currently facing up; then the 3D printing control preparation method further includes: repeating steps S420 to S440 to encapsulate and print the side surfaces to be printed of the stacked sheet structure one by one to complete the encapsulation of the stacked sheet structure; obtaining the encapsulated stacked sheet structure. In this embodiment, in step S420, when encapsulating different side surfaces to be printed, it is necessary to adjust the side surface to be printed that is facing up. For example, rotate the stacked sheet structure to make the side surface to be printed face up.

[0196] Optionally, if the solid contour data of the side surface to be printed obtained in step S430 is the solid contour data of the entire circumferential side surface of the stacked sheet structure in step S410, then the printing path obtained in step S430 is the printing path of all the side surfaces to be printed of the entire circumferential side surface. Then, when encapsulating different side surfaces to be printed, it is only necessary to adjust the current side surface to be printed to face up. For example, rotate the stacked sheet structure to make the side surface to be printed face up.

[0197] In some embodiments, the 3D printing control preparation method further includes: performing a hot pressing treatment on the stacked sheet structure provided with the 3D printing overhang slurry. In this embodiment, the relevant content of the hot pressing treatment can refer to the foregoing relevant content and will not be elaborated here.

[0198] In the preparation method of the battery cell according to the embodiment of the present disclosure, after the encapsulation is completed, for example, after step S440 or after performing a hot pressing treatment on the stacked sheet structure provided with the 3D printing overhang slurry, a compression treatment can also be performed on the stacked sheet structure provided with the 3D printing overhang slurry, such as isostatic pressing treatment, so that the layers in the stacked sheet structure are pressed and connected to each other.

[0199] In the preparation method according to the embodiment of the present disclosure, the operation of placing the stacked sheet structure provided with the 3D printing overhang slurry obtained by printing on the hot pressing device can be completed manually or through an automated transfer device, which can be determined according to the actual situation.

[0200] The embodiment of the present disclosure further provides a solid-state battery, including: the electrode tab of any one of the foregoing embodiments; or, the battery cell of any one of the foregoing embodiments; or the battery cell prepared by the preparation method of the battery cell of any one of the foregoing embodiments.

[0201] Specific embodiments are given below to specifically illustrate the 3D printing overhang slurry, electrode sheet, battery cell and their preparation methods and solid-state batteries 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 a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present application and its application.

[0202] For those not specifying specific techniques or conditions in the embodiments, follow the techniques or conditions described in the literature in the art or according to the product specifications. For reagents or instruments not indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0203] Example 1 As Figure 3 and Figure 6 shown, a solid-state battery, the specific preparation method is as follows: (1) Preparation of the positive electrode sheet The positive electrode active material layer is prepared by a dry process. The positive electrode active slurry is mixed in a glove box in a ratio of NCM:LPSCl:SP:PTFE = 70:24:5:1 to form a mixture. Among them, the NCM material refers to lithium nickel cobalt manganese oxide material, LPSCl is a thioargentite-type electrolyte, SP is conductive carbon black, and PTFE is polytetrafluoroethylene. After being uniformly mixed by a high-speed dispersion and kneading machine for 2 h, the mixture is then ball-milled to make the PTFE fibrous, and a fibrillated powder is obtained; the fibrillated powder is extruded at 80 °C to form a sheet with a thickness of 250-400 μm, and then rolled to 97 μm to obtain the positive electrode active material layer. The positive electrode active material layer is die-cut into a size of 112 mm * 84 mm, and it is thermally roll-compounded with a positive electrode current collector of 116 mm * 88 mm. In the same way, an active material layer is thermally roll-pressed on the other side of the positive electrode current collector to obtain a dry-process electrode sheet.

[0204] (2) Processing of the positive electrode sheet Weigh 7 g of polyisobutylene and slowly add it to 40 g of N-methylpyrrolidone (NMP) solvent, place it on a magnetic stirrer and stir for 4 h. The obtained mixed solution is placed in the barrel of a 3D printer, and a packaging structure is printed in the empty foil area around the electrode sheet obtained in step (1). The single-sided processed electrode is transferred to an oven and cured at a low temperature of 60 °C for 1 h. After cooling, the single-sided packaging structure has a thickness of 97 μm and a width of 2 mm. Print on the other side of the electrode sheet in the same way, and finally obtain a positive electrode sheet with packaging structures on both sides.

[0205] (3) Preparation of the combined negative electrode sheet Weigh each component material according to the weight ratio of micro - silicon: polyvinylidene fluoride (PVDF): vapor - grown carbon fiber (VGCF) = 95:3:2. Dissolve PVDF in NMP to prepare a 7wt% binder solution. Ball - mill and mix micro - silicon and VGCF for 30 min. Add the binder solution to the mixed powder to prepare a 68wt% negative electrode slurry. Homogenize and disperse it in a degassing machine for 3 h to obtain the negative electrode active slurry. Coat the obtained negative electrode active slurry on the surface of the copper foil, dry it, and then roll - press and die - cut it into 116 mm * 88 mm. Weigh each component according to the weight ratio of sulfide solid electrolyte (LPSCl): styrene - butadiene - styrene block copolymer (SEBS) = 98:2. Dissolve SEBS in anisole solvent at 5wt% and prepare a glue solution by magnetic stirring for 30 min. Then add the electrolyte powder according to the weight ratio to the glue solution and disperse it with a degassing machine for 1 h to prepare the electrolyte slurry. Use a 50um blade to scrape - coat the electrolyte slurry on a 15um stainless - steel foil, and bake it in a vacuum oven at 80°C to volatilize the solvent to obtain the solid electrolyte layer. Align the above - prepared solid electrolyte layer with the negative electrode and perform cold pressing under a pressure of 3T on a rolling press. Manually tear the stainless - steel sheet and transfer the solid electrolyte layer to the negative electrode interface to obtain the combined negative electrode sheet.

[0206] (4)Cell assembly Assemble the processed positive electrode sheet and the transferred combined negative electrode sheet together through the stacking process to form a solid - state cell; vacuum - encapsulate the solid - state cell with an aluminum - plastic film; apply the isostatic pressing process, and then heat - treat it under a certain pressure to obtain a solid - state lithium - ion battery with a packaging structure.

[0207] Example 2: As Figure 4 and Figure 7 shown, a solid - state battery, the specific preparation method is as follows: (1)Positive electrode sheet preparation Prepare the positive electrode sheet by the wet method: Disperse NCM, LPSCl, carbon nanotubes (CNT), and styrene - butadiene rubber (SBR) in the solvent NMP according to the mass ratio of 68.6:29.4:1:1, control the solid content at about 50%, and coat the slurry on the conductive carbon layer by the traditional wet method. Vacuum - dry the coated sheet at 120°C for 10 h, roll - press and die - cut it into a size of 112 mm * 84 mm to obtain the wet - method positive electrode sheet.

[0208] (2)Negative electrode sheet preparation Weigh each component material according to the weight ratio of micro-silicon:PVDF:VGCF = 95:3:2. Dissolve PVDF in NMP to prepare a 7wt% binder solution. Ball-mill and mix micro-silicon and VGCF for 30 minutes. Add the binder solution to the mixed powder to prepare a 68wt% negative electrode slurry, and homogenize and disperse it in a degassing machine for 3 hours to obtain a negative electrode active slurry. Coat the obtained negative electrode active slurry on the surface of the copper foil, dry it, and then roll and die-cut it into 116 mm * 88 mm.

[0209] (3)Negative electrode sheet processing Weigh 7 g of polyisobutylene and slowly add it to 40 g of N-methylpyrrolidone solvent. Place it on a magnetic stirrer and stir for 4 hours. Put the obtained mixed solution into the barrel of a 3D printer and print an encapsulation structure on the edge of the negative electrode sheet obtained in step (2). Transfer the singly processed electrode sheet to an oven and cure it at a low temperature of 60 °C for 1 hour. After cooling, the encapsulation structure on one side has a thickness of 124 μm and a width of 2 mm. Print on the other side of the sheet in the same way, and finally obtain a negative electrode sheet with encapsulation structures on both sides.

[0210] (4)Preparation of self-supporting sulfide solid electrolyte layer Mix PTFE powder and LPSCl electrolyte powder evenly by hand grinding according to a mass ratio of 10:90; knead the obtained electrolyte mixture by a kneader at 160 °C under shear, and then process the sheared and kneaded electrolyte mixture into a sheet shape at 260 °C by flat plate static pressure (500 MPa, 50 min); the obtained electrolyte sheet is densified by isostatic pressing to obtain a 20 μm LPSCl solid electrolyte layer.

[0211] (5)Cell assembly Assemble the positive electrode sheet, solid electrolyte layer, and processed negative electrode sheet together by a stacking process to form a solid-state cell; vacuum package the solid-state cell with an aluminum-plastic film; process it by an isostatic pressing process, and then heat-treat it under a certain pressure to obtain a solid-state lithium-ion battery with an encapsulation structure.

[0212] Example 3: As Figure 5 and Figure 8 shown, a solid-state battery, the specific preparation method is as follows: (1)Positive electrode sheet preparation Disperse NCM, LPSCl, CNT, and SBR according to a mass ratio of 68.6:29.4:1:1 into the solvent NMP, control the solid content at about 50%, coat the slurry on the conductive carbon layer by the traditional wet method, vacuum dry the coated sheet at 120 °C for 10 hours, roll and die-cut it into a size of 112 mm * 84 mm to obtain a wet-process positive electrode sheet.

[0213] (2) Preparation of Composite Anode Plate Weigh the component materials according to the weight ratio of micron silicon: PVDF: VGCF = 95:3:2. Dissolve PVDF in NMP to prepare a 7wt% binder solution. Ball-mill and mix micron silicon and VGCF for 30 min. Add the binder solution to the mixed powder to prepare a 68wt% anode slurry, and homogenize and disperse it in a degassing machine for 3 h to obtain the anode slurry. Coating the obtained slurry on the surface of copper foil, drying and then roll-pressing and die-cutting it into 116 mm * 88 mm. Weigh each component according to the weight ratio of LPSCl: SEBS = 98:2. Dissolve SEBS in anisole solvent at 5wt% and prepare a glue solution by magnetic stirring for 30 min. Subsequently, add the electrolyte powder according to the weight ratio to the glue solution and disperse it with a degassing machine for 1 h to prepare the electrolyte slurry. Use a 50um blade to scrape the electrolyte slurry on a 15um stainless steel foil, and bake it in a vacuum oven at 80 °C to volatilize the solvent to obtain a solid electrolyte layer. Align the above-prepared solid electrolyte layer with the anode, and perform cold pressing under a pressure of 3T on a roll press. Manually tear the stainless steel sheet to transfer the solid electrolyte layer to the anode interface to obtain a composite anode plate.

[0214] (3) Processing of Composite Anode Plate Weigh 7g of polyisobutylene and slowly add it to 40g of NMP solvent, place it on a magnetic stirrer and stir for 4 h. Put the obtained mixed solution into the barrel of a 3D printer, and print the encapsulation structure on the edge of the composite anode plate obtained in step (2). Transfer the single-sided processed electrode to an oven and cure it at a low temperature of 60 °C for 1 h. After cooling, the single-sided encapsulation structure has a thickness of 104 μm and a width of 2 mm. Print on the other side of the anode plate in the same way, and finally obtain a composite anode plate with encapsulation structures on both sides.

[0215] (4) Cell Assembly Assemble the positive electrode plate and the processed composite anode plate together through the lamination process to form a solid-state cell; vacuum encapsulate the solid-state cell with an aluminum-plastic film; apply the isostatic pressing process and then heat-treat it under a certain pressure to obtain a solid-state lithium-ion battery with an encapsulation structure.

[0216] Example 4: The difference between the solid-state battery of this embodiment and that of Embodiment 1 lies only in that in step (2) for preparing the encapsulation structure, 7 g of polyisobutylene is slowly added to 40 g of NMP solvent, and the mixture is placed on a magnetic stirrer and stirred for 4 h. After the polyisobutylene is completely dissolved, 3 g of lithium phytate is added, and stirring is continued for 1 h. The resulting mixed solution is placed in the cartridge of a 3D printer, and the encapsulation structure is printed in the empty foil area around the electrode sheet obtained in step (1) of Embodiment 1. The electrode sheet processed on one side is transferred to an oven and cured at a low temperature of 60 °C for 1 h. After cooling, the encapsulation structure on one side has a thickness of 97 μm and a width of 2 mm, and is printed on the other side of the electrode sheet in the same manner. Finally, a positive electrode sheet with encapsulation structures on both sides is obtained. The remaining steps and parameters are the same as those in Embodiment 1.

[0217] Embodiment 5: The difference between the solid-state battery of this embodiment and that of Embodiment 2 lies only in that in step (3) for preparing the encapsulation structure, 7 g of polyisobutylene is slowly added to 40 g of NMP solvent, and the mixture is placed on a magnetic stirrer and stirred for 4 h. After the polyisobutylene is completely dissolved, 3 g of lithium phytate is added, and stirring is continued for 1 h. The resulting mixed solution is placed in the cartridge of a 3D printer, and the encapsulation structure is printed at the edge of the negative electrode sheet obtained in step (2) of Embodiment 2. The electrode sheet processed on one side is transferred to an oven and cured at a low temperature of 60 °C for 1 h. After cooling, the encapsulation structure on one side has a thickness of 124 μm and a width of 2 mm, and is printed on the other side of the negative electrode sheet in the same manner. Finally, a negative electrode sheet with encapsulation structures on both sides is obtained. The remaining steps and parameters are the same as those in Embodiment 2.

[0218] Embodiment 6: The difference between the solid-state battery of this embodiment and that of Embodiment 3 lies only in that in step (3) for preparing the encapsulation structure, 7 g of isobutene is slowly added to 40 g of NMP solvent, and the mixture is placed on a magnetic stirrer and stirred for 4 h. After the isobutene is completely dissolved, 3 g of lithium phytate is added, and stirring is continued for 1 h. The resulting mixed solution is placed in the cartridge of a 3D printer, and the encapsulation structure is printed at the edge of the combined negative electrode sheet obtained in step (2) of Embodiment 3. The electrode processed on one side is transferred to an oven and cured at a low temperature of 60 °C for 1 h. After cooling, the support encapsulation structure on one side has a thickness of 104 μm and a width of 2 mm, and is printed on the other side of the electrode sheet in the same manner. Finally, a combined negative electrode sheet with encapsulation structures on both sides is obtained. The remaining steps and parameters are the same as those in Embodiment 3.

[0219] Comparative Example 1: The difference from Embodiment 1 is that step (2) is not included, that is, the printing of the encapsulation structure in step (2) is not carried out. The remaining steps and parameters are the same as those in Embodiment 1.

[0220] Comparative Example 2: The difference from Example 2 is that step (3) is not included, that is, the printing of the encapsulation structure in step (3) is not carried out. The remaining steps and parameters are the same as those in Example 2.

[0221] Comparative Example 3: The difference from the example is that step (3) is not included, that is, the printing of the encapsulation structure in step (3) is not carried out. The remaining steps and parameters are the same as those in Example 3.

[0222] The solid-state batteries of the above Examples 1 to 6 and Comparative Examples 1 to 3 were subjected to charge and discharge tests. The charge and discharge interval was 2.1V to 4.3V, and the test temperature was 30 °C. The test results are shown in Table 1 (0.1C cycle), and the obtained charge and discharge test performance data are shown in Table 1.

[0223] Table 1

[0224] From the results of the above examples and comparative examples, it can be found that the sulfide solid-state battery with an encapsulation structure can effectively avoid the short-circuit phenomenon of the battery during the pressurized assembly and pressurized operation processes. The yield of the battery cores in the 6 examples with the encapsulation structure has been greatly improved. Even though the battery in Comparative Example 1 passed the short-circuit test during the trial production process, its capacity performance was poor in the subsequent charge and discharge cycles, indicating that there was a micro short-circuit inside the battery. The specific capacity, first efficiency, etc. of the battery cores in Examples 4 to 6 are similar to those in Examples 1 to 3, indicating that the addition of the functional material does not affect the function of the encapsulation structure. After 100 cycles, the capacity performance of Examples 4 to 6 with the addition of the functional material (lithium phytate) is better than that of Examples 1 to 3. The reason is that lithium phytate quenches the oxygen free radicals or oxygen released during the positive electrode cycle process, reducing the decomposition and side reactions of the sulfide electrolyte, thus showing better capacity performance and cycle performance.

[0225] From the above description, it can be seen that the above examples of the present invention achieve the following technical effects: The D printing 3D printing overhang paste provided by this application solves the short-circuit problem of the solid-state battery caused by the overhang problem, and at the same time, further improves the performance of the battery core through the addition of the functional material.

[0226] The above description and the accompanying drawings fully illustrate the embodiments of the present disclosure, enabling those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, process, and other changes. The embodiments only represent possible variations. Unless explicitly required, the individual components and functions are optional, and the order of operations may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terms used in this application are only for describing the embodiments and do not limit the claims. As used in the description of the embodiments and the claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to also include the plural forms. Similarly, as used in this application, the term "and / or" refers to any and all possible combinations of one or more of the associated listed items. Additionally, when used in this application, the term "comprise" and its variants "comprises" and / or "comprising" etc. mean the presence of the 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 of these. Without further limitation, an element defined by the statement "comprising one..." does not exclude the presence of additional identical elements in the process, method, or device comprising the element. Herein, each embodiment may focus on the differences from other embodiments, and the same or similar parts among the embodiments may be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method part disclosed in the embodiments, the relevant parts may refer to the description of the method part.

[0227] Those skilled in the art can realize that the units and steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner can depend on the specific application and design constraints of the technical solution. The skilled person can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the embodiments of the present disclosure. The skilled person can 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 foregoing method embodiments, and will not be elaborated herein.

[0228] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a segment of a program, or a portion of code, which contains one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions noted in the blocks may occur in a different order than noted in the accompanying drawings. For example, two consecutive blocks may in fact be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending 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 blocks may also occur in a different order than disclosed in the description, and sometimes there is no specific order between different operations or steps. For example, two consecutive operations or steps may in fact be executed substantially in parallel, or they may sometimes be executed in the reverse order, depending on the functions involved. Each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system that performs the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

Claims

1. A 3D printing overhang paste, characterized in that, Comprising: A polymer substrate, a functional material, and a solvent. The functional material includes one or more of an oxygen adsorbent, a water adsorbent, and an endothermic agent. Among them, the solid content of the 3D printing overhang slurry is 20% - 80%, and the mass ratio of the polymer substrate to the functional material is (70 - 90):(10 - 30).

2. The 3D printing overhang slurry according to claim 1, wherein The mass percentage of the polymer substrate in the dry solid content of the 3D printing overhang slurry is 60% - 90%, or the mass percentage of the polymer substrate in the dry solid content of the 3D printing overhang slurry is 70% - 90%, or the mass percentage of the polymer substrate in the dry solid content of the 3D printing overhang slurry is 60% - 80%; and / or, The mass percentage of the functional material in the dry solid content of the 3D printing overhang slurry is 5% - 40%, or the mass percentage of the functional material in the dry solid content of the 3D printing overhang slurry is 10% - 40%, or the mass percentage of the functional material in the dry solid content of the 3D printing overhang slurry is 10% - 35%, or the mass percentage of the functional material in the dry solid content of the 3D printing overhang slurry is 10% - 30%; and / or, The polymer substrate includes one or more of polyisobutene, polyphenylene ether, polyimide, polyacrylonitrile, polyvinylidene fluoride, polyethylene glycol, polyethylene oxide, sodium carboxymethyl cellulose, styrene-butadiene rubber, and polyacrylic acid; and / or, The solvent includes one or more of dimethyl sulfoxide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethylformamide; and / or, The water adsorbent includes one or more of zeolite, calcium chloride, magnesium chloride, sodium polyacrylate, and polyvinyl alcohol; and / or, The oxygen adsorbent includes one or more of polydopamine, lithium phytate, 4-tert-butylcatechol, N-phenyl-N'-phenyl-p-phenylenediamine, naphthylamine, diphenylamine, and p-phenylenediamine; and / or, The endothermic agent includes one or more of polyethylene glycol and polyvinyl alcohol.

3. The 3D printing overhang slurry according to claim 2, wherein The solid content of the 3D printing overhang slurry is ​ The functional materials include a water adsorbent, and the mass percentage of the water adsorbent in the functional materials is 20% - 70%, or the mass percentage of the water adsorbent in the functional materials is 20% - 60%, or the mass percentage of the water adsorbent in the functional materials is 30% - 60%; and / or, The functional materials include an endothermic agent, and the mass percentage of the endothermic agent in the functional materials is 10% - 50%, or the mass percentage of the endothermic agent in the functional materials is 20% - 50%, or the mass percentage of the endothermic agent in the functional materials is 20% - 40%; and / or, The polymer substrate includes one or more of polyvinylidene fluoride, polyacrylonitrile, and polyethylene oxide; and / or, The oxygen adsorbent includes one or more of polydopamine nanoparticles and lithium phytate; and / or, The water adsorbent includes zeolite; and / or, The endothermic agent includes polyethylene glycol.

4. The 3D printing overhang paste according to claim 2, wherein The solid content of the 3D printing overhang paste is 60% - 80%, or the solid content of the 3D printing overhang paste is 65% - 80%, or the solid content of the 3D printing overhang paste is 60% - 75%; and / or, The polymer substrate includes a first polymer and a second polymer. The elastic modulus of the first polymer is greater than that of the second polymer, and the strength of the second polymer is greater than that of the first polymer. Wherein, the content of the first polymer is greater than that of the second polymer, or the mass percentage of the first polymer in the polymer substrate is 50% - 80%, or the mass percentage of the first polymer in the polymer substrate is 50% - 75%, or the mass percentage of the first polymer in the polymer substrate is 60% - 75%; and / or, the mass percentage of the second polymer in the polymer substrate is 20% - 60%, or the mass percentage of the second polymer in the polymer substrate is 25% - 50%, or the mass percentage of the second polymer in the polymer substrate is 25% - 40%; and / or, The functional materials include an endothermic agent, and the mass percentage of the endothermic agent in the functional materials is 60% - 100%, or the mass percentage of the endothermic agent in the functional materials is 80% - 100%, or the mass percentage of the endothermic agent in the functional materials is 60% - 90%.

5. The 3D printing overhang paste according to claim 4, wherein The first polymer includes polyisobutene, and the second polymer includes polyimide or polyphenylene ether; and / or, The endothermic agent includes polyethylene glycol or polyvinyl alcohol; and / or, The functional materials further include a reinforcing agent, and the reinforcing agent includes hydrophobic fumed silica; and / or, The functional materials further include a reinforcing agent, and the mass percentage of the reinforcing agent in the functional materials is 0 - 40%.

6. The preparation method of the 3D printing overhang paste according to any one of claims 1 to 5, characterized in that, Comprising: Preparing each raw material according to the 3D printing overhang paste as described in any one of claims 1 to 5; Adding the polymer substrate to a solvent and dissolving to obtain solution A; Adding the functional materials to solution A to obtain the 3D printing overhang paste.

7. An electrode sheet, characterized in that, The electrode plate is a positive electrode plate or a negative electrode plate; When the electrode plate includes a positive electrode plate, the positive electrode plate includes an empty foil area, and a 3D printed overhang paste is provided in the empty foil area; When the electrode plate includes a negative electrode plate, the negative electrode plate includes an overhang area, and a 3D printed overhang paste is provided in the overhang area of the negative electrode plate; When the electrode plate includes a negative electrode plate and the negative electrode plate is a composite negative electrode plate with solid electrolyte layers provided on both of its side surfaces, a 3D printed overhang paste is provided on the surface of the solid electrolyte layer of the composite negative electrode plate corresponding to the overhang area of the negative electrode plate; Wherein, the 3D printed overhang paste is the 3D printed overhang paste according to any one of claims 1 to 5 or the 3D printed overhang paste obtained by the preparation method of the 3D printed overhang paste according to claim 6.

8. A battery cell, characterized in that, It includes a stacked structure, the stacked structure includes alternately stacked positive electrode plates and negative electrode plates, and a solid electrolyte layer is provided between adjacent positive electrode plates and negative electrode plates; at least one side in the circumferential direction of the negative electrode plate extends beyond the positive electrode plate to form an overhang area; wherein, a packaging structure is provided in the overhang void area corresponding to the overhang area; Wherein, the packaging structure is obtained by providing a 3D printed overhang paste in the overhang void area; the 3D printed overhang paste is the 3D printed overhang paste according to any one of claims 1 to 5 or the 3D printed overhang paste obtained by the preparation method of the 3D printed overhang paste according to claim 6.

9. The battery cell according to claim 8, wherein, The packaging structure includes a connected filling part and a covering part, the filling part is located in the overhang void area, the covering part covers the circumferential side surface of the stacked structure, the filling part is formed by the 3D printed overhang paste according to any one of claims 1 to 3, and / or, the covering part is formed by the 3D printed overhang paste according to any one of claims 1, 2, 4 and 5.

10. The battery cell according to claim 8 or 9, characterized in that, The positive electrode plate adopts the positive electrode plate in the electrode plate according to claim 7; or, the negative electrode plate adopts the negative electrode plate or the composite negative electrode plate in the electrode plate according to claim 7.

11. The method for preparing an electric core according to any one of claims 8 to 10, characterized in that, It includes: Preparing a positive electrode plate, a negative electrode plate and a solid electrolyte layer; wherein, the size of the negative electrode plate is larger than that of the positive electrode plate at least on one side in the circumferential direction, so that the negative electrode plate has an overhang area; wherein, the positive electrode plate adopts the positive electrode plate according to claim 7, or, the negative electrode plate adopts the negative electrode plate or the composite negative electrode plate according to claim 7; Stacking the positive electrode plate and the negative electrode plate alternately, and providing a solid electrolyte layer between adjacent positive electrode plates and negative electrode plates to obtain a battery cell; wherein, a cured 3D printed overhang paste is provided at the overhang void of the battery cell.

12. The method for preparing a battery cell according to claim 11, wherein, Before the positive electrode plate and the negative electrode plate are alternately stacked, it further includes: 3D printing an overhang paste as described in any one of claims 1 to 3 on the positive electrode plate or the negative electrode plate, and curing the 3D printed overhang paste to obtain a positive electrode plate or a negative electrode plate with a filling part; or, After the positive electrode plate and the negative electrode plate are alternately stacked, the stacked battery cell structure after stacking is cured to obtain a battery cell with a packaging structure.

13. The method for preparing a battery cell according to claim 12, wherein, After obtaining a positive electrode plate or a negative electrode plate with a filling part, it further includes: 3D printing an overhang paste as described in claim 1, 2, 4 or 5 on the circumferential side surface of the battery cell, and curing the 3D printed overhang paste to form a coating part, and the coating part is connected to the filling part.

14. The method for preparing an electric core according to claim 8 or 9, characterized in that, It includes: Stacking the positive electrode plate, the solid electrolyte layer, the negative electrode plate and the solid electrolyte layer in this order to obtain a stacked structure; wherein, a hanging void area is formed on the circumferential side surface of the stacked structure; Setting an overhang paste for 3D printing into the hanging void area of the stacked structure to obtain a battery cell with a packaging structure.

15. The method for preparing a battery cell according to claim 14, wherein, Setting an overhang paste for 3D printing into the hanging void area of the stacked structure to obtain a battery cell with a packaging structure; it includes: Setting an overhang paste for 3D printing as described in any one of claims 1 to 3 into the hanging void area of the stacked structure to obtain a first stacked structure with a filling part; Setting an overhang paste for 3D printing as described in claim 1, 2, 4 or 5 into the hanging void area of the first stacked structure, and connecting and forming a coating part outside the filling part to obtain a battery cell with a packaging structure; wherein, the outer surface of the coating part is flush with the circumferential side surface of the stacked structure, or the coating part protrudes from the circumferential side surface of the stacked structure and wraps the circumferential side surface of the stacked structure.

16. The method for preparing an electric cell according to claim 14 or 15, characterized in that, Using a 3D printing method to set an overhang paste for 3D printing into the hanging void area of the stacked structure to obtain a 3D printing control preparation method, which includes: Stacking the positive electrode plate, the solid electrolyte layer, the negative electrode plate and the solid electrolyte layer in this order to obtain a stacked structure; wherein, a hanging void area is formed on the circumferential side surface of the stacked structure; Vertically arranging the stacked structure in the printing area of the 3D printing device with the side to be printed facing upwards; Obtaining the contour solid data of the side to be printed of the stacked structure; obtaining a contour three-dimensional model according to the contour solid data; performing slicing processing on the contour three-dimensional model, performing path planning and printing parameter design to obtain printing information; The 3D printing device prints and sets the overhang paste for 3D printing on the side to be printed according to the printing information, completes the encapsulation printing of the side to be printed of the stacked structure, and obtains a stacked structure provided with the overhang paste for 3D printing.

17. A solid-state battery, characterized in that, It includes: The electrode sheet according to claim 7; or, the battery cell according to any one of claims 8 to 10; or the battery cell obtained by the preparation method of the battery cell according to any one of claims 11 to 16.

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