Battery cells and their packaging methods, packaging systems, solid-state batteries, and hot-melt resin materials

Abstract

This application relates to the field of solid-state battery technology, disclosing a battery cell including a stacked structure and a packaging structure. The stacked structure includes alternately stacked negative and positive electrode sheets, with a solid electrolyte layer disposed between adjacent positive and negative electrode sheets. The peripheral surfaces of the stacked structure form sheet-like gaps. The packaging structure includes a filling portion and a permeation portion. The filling portion is disposed in the sheet-like gaps, and the permeation portion extends from the filling portion and permeates into the sheet layers. The permeation portion ensures the interfacial bonding effect between the packaging structure and the sheet layers of the stacked structure, improving the bonding strength. Furthermore, the permeation portion penetrates into the active material region of the electrode sheets, enhancing cohesion and providing a certain degree of deformation capability to adapt to the molding pressure of the stacked battery cell and the volume changes of the active material. This prevents the packaging structure from detaching from the sheet layers and avoids excessive deformation leading to new edge stress, thereby improving the performance of the solid-state battery. This application also discloses a packaging method, a packaging system, a solid-state battery, and a hot-melt resin material.

Description

Technical Field

[0001] This application relates to the field of solid-state battery technology, such as a battery cell and its packaging method, packaging system, solid-state battery, and hot-melt resin material. Background Technology

[0002] Extremely high energy density, high rate capability, high safety, long lifespan, wide temperature range, and low cost are the goals that power batteries have always pursued. With the rapid development of new energy vehicles, traditional lithium-ion batteries using liquid electrolytes are gradually failing to meet market demands for battery performance, necessitating the development of next-generation battery technologies. Solid-state batteries use solid electrolytes with higher mechanical strength, and the amount of electrolyte used and interfacial side reactions are far less than in liquid batteries, thus offering significant advantages in energy density, safety, lifespan, and climate adaptability. Due to the solid-solid contact between components and the high interfacial impedance, solid-state batteries require pressurized densification during manufacturing. Traditional winding processes are difficult to accommodate the enormous molding pressure; therefore, stacking processes based on roll forming or isostatic pressing have become the preferred choice for current solid-state batteries.

[0003] In solid-state battery stacking processes, the equal-sized positive and negative electrode sheets can become misaligned due to insufficient precision in the stacking equipment. This misalignment can lead to lithium plating at the negative electrode edge during charging and discharging, posing a short-circuit risk. To address this issue, the negative electrode area is typically designed to be slightly larger than the positive electrode area, allowing the negative electrode to completely cover the positive electrode (i.e., overhang design). However, due to the unequal size of the positive and negative electrodes, applying significant forming pressure (such as isostatic pressing or rolling) can easily induce stress concentration at the electrode edges. Under shear force, this can cause electrolyte membrane edge breakage, leading to internal short circuits at the positive and negative electrode edge contacts, reducing battery manufacturing yield, especially in the manufacture of multi-layer solid-state cells where the yield decline is more significant. To address the yield issues of overhang stacking and isostatic pressing processes in solid-state batteries, those skilled in the art have conducted corresponding research on short-circuit resistant solid-state batteries.

[0004] Currently, to address the issue of the negative electrode overhang region easily collapsing during solid-state battery assembly, leading to contact between the positive and negative electrodes and potentially causing a short circuit, most methods involve filling the gaps in the negative electrode overhang region with material for encapsulation and support to prevent collapse. However, in actual R&D, it has been found that existing encapsulation and support structures for the overhang region deform under stress during the electrostatic pressing process of stacked cells, resulting in significant shrinkage in size. This leads to inconsistent deformation / shrinkage between the electrode and the encapsulation and support structure, causing localized debonding of the encapsulation and support structure, and even complete detachment from the electrode edge. Consequently, the cell yield cannot be effectively improved, and it may even affect the subsequent improvement of battery performance.

[0005] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this application, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general commentary, nor is it intended to identify key / important components or describe the scope of protection of these embodiments, but rather as a prelude to the detailed description that follows.

[0007] This disclosure provides a battery cell and its packaging method, packaging system, solid-state battery, and hot-melt resin material to solve the problem that the existing laminated battery cell's layer gap packaging structure is prone to debonding, and may even easily fall off the entire sheet from the edge of the electrode, affecting battery yield and subsequent battery performance.

[0008] In some embodiments, the battery cell includes: a laminated structure comprising alternately stacked negative and positive electrode sheets, with a solid electrolyte layer disposed between adjacent positive and negative electrode sheets; a lamination gap is formed on the peripheral side of the laminated structure; and an encapsulation structure comprising a filling portion and a permeation portion, the filling portion being disposed in the lamination gap of the laminated structure, and the permeation portion being a portion extending from the filling portion into the lamination interior surrounding the lamination gap; the permeation depth of the permeation portion being greater than or equal to 1 μm.

[0009] In some embodiments, the encapsulation method of the battery cell includes: stacking a positive electrode sheet, a negative electrode sheet, and a solid electrolyte layer in the order of a positive electrode sheet, a solid electrolyte layer, a negative electrode sheet, and a solid electrolyte layer to obtain a stacked structure; wherein, a layer gap is formed on the peripheral side of the stacked structure; and dispensing an encapsulation material into the layer gap of the stacked structure to obtain a battery cell with an encapsulation structure; wherein, the encapsulation material can penetrate into the interior of the layers surrounding the layer gap to form a permeable portion.

[0010] In some embodiments, the solid-state battery includes: the aforementioned battery cell; or, a battery cell obtained by the aforementioned battery cell packaging method.

[0011] In some embodiments, the battery cell packaging system includes: a fluid material precision coating device; a conveying and positioning module for flipping the completed stacked structure to a vertical position and conveying it to the working area of ​​the fluid material precision coating device; a scanning module for scanning the contour entity data of the side of the stacked structure to be printed located in the working area of ​​the fluid material precision coating device; a control unit for obtaining a contour 3D model based on the contour entity data; slicing the contour 3D model, performing path planning and coating parameter design to obtain coating information; the fluid material precision coating device receiving the coating information from the control unit and, based on the coating information, setting molten packaging material heated to a preset temperature onto the side of the stacked structure to be printed located in the working area.

[0012] In some embodiments, the hot-melt resin material serves as the encapsulation material for the aforementioned battery cell encapsulation structure, or as the encapsulation material in the aforementioned battery cell encapsulation method; or as the encapsulation material used in the 3D printing equipment of the aforementioned battery cell encapsulation system; the hot-melt resin material comprises, by weight, 40-80 parts of matrix resin, 5-10 parts of compatibilizer, 0-3 parts of coupling agent, and 0-60 parts of inorganic filler; wherein the matrix resin comprises a polymer containing one or more polar functional groups selected from ester, carboxyl, anhydride, amide, amino, hydroxyl, and epoxy groups.

[0013] In some embodiments, the solid-state battery includes: the aforementioned battery cell; or, a battery cell packaged using the aforementioned battery cell packaging method; or, a battery cell packaged using the aforementioned battery cell packaging system.

[0014] The battery cell, its packaging method, packaging system, solid-state battery, and hot-melt resin material provided in this disclosure can achieve the following technical effects:

[0015] In the battery cell of this disclosure embodiment, the encapsulation structure includes, in addition to the filling portion disposed in the gaps between the layers of the stacked structure, a permeation portion that penetrates into the layers surrounding the gaps between the layers. The permeation portion ensures the interfacial bonding effect between the encapsulation structure and the layers of the stacked structure, improves the bonding strength between the encapsulation structure and the layers, and the permeation portion penetrates into the active material area of ​​the electrode sheet to enhance cohesion and has a certain deformation capability to adapt to the molding pressure of the stacked battery cell and the volume change of the active material (including the volume change caused by molding pressure and charging and discharging). This avoids the encapsulation structure from detaching from the layers (electrode sheets and / or solid electrolyte layer), especially in the static pressure molding process of solid-state batteries, where excessive deformation of the layers causes the encapsulation structure to detach from the layers, forming new edge stress. That is, the battery cell of this disclosure overcomes the technical limitations of the existing layered void encapsulation structure. By designing it so that the encapsulation material penetrates into the electrode material region, although theoretical calculations show a very small energy loss (generally controlled within 1%), the bonding strength between the encapsulation structure and the stacked structure is improved, and it will not detach. In particular, it will not detach even after the solid-state battery isostatic pressing process, which improves the battery yield and can also improve the utilization rate of electrode active materials and enhance the performance of solid-state batteries.

[0016] The cell packaging method of this disclosure is more practical. It can use continuously coated electrodes, is compatible with overhang design and size equal design of positive and negative electrodes, and can simplify the edge short-circuit protection treatment of a single electrode to edge short-circuit protection packaging of a stacked structure, which greatly reduces the difficulty, cycle and cost of battery manufacturing process.

[0017] The above general description and the description below are exemplary and illustrative only and are not intended to limit this application. Attached Figure Description

[0018] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations and drawings do not constitute a limitation on the embodiments. Elements having the same reference numerals in the drawings are shown as similar elements. The drawings are not to be scaled. And wherein:

[0019] Figure 1 This is a schematic diagram of the structure of a battery cell provided in an embodiment of this disclosure;

[0020] Figure 2 This is a partially enlarged structural schematic diagram of another battery cell provided in an embodiment of this disclosure;

[0021] Figure 3 This is a schematic diagram of another battery cell structure provided in an embodiment of this disclosure;

[0022] Figure 4 This is a schematic diagram of another battery cell structure provided in an embodiment of this disclosure;

[0023] Figure 5 This is a schematic flowchart of a battery cell packaging method provided in an embodiment of this disclosure;

[0024] Figure 6 This is a schematic flowchart of another battery cell packaging method provided in this embodiment of the present disclosure;

[0025] Figure 7 This is a schematic diagram of the structure of a hot pressing device provided in an embodiment of this disclosure;

[0026] Figure 8 This is a schematic diagram of the structure of a battery cell packaging system provided in an embodiment of this disclosure;

[0027] Figure 9a This is a cross-sectional scanning electron microscope image of the battery cell of Embodiment 1 of this disclosure;

[0028] Figure 9b This is an EDS elemental analysis photograph of a cross-section of the battery cell of Embodiment 1 of this disclosure;

[0029] Figure 10a This is a cross-sectional scanning electron microscope photograph of the battery cell of Comparative Example 5 disclosed herein;

[0030] Figure 10b This is an EDS elemental analysis photograph of a cross section of the battery cell of Comparative Example 5 disclosed herein;

[0031] Figure 11a and Figure 11b This is a schematic diagram of the battery cell's packaging structure under deformation or detachment conditions, as shown in Comparative Example 5 of this disclosure.

[0032] Figure 12 These are charge-discharge curves of the battery cells of Embodiment 1 and Comparative Example 1 of this disclosure;

[0033] Figure 13 This is a cycle performance diagram of the unshort-circuited cells of the cells of Embodiment 1 and Comparative Example 1 of this disclosure.

[0034] Figure label:

[0035] 10. Stacked structure; 11. Negative electrode; 111. Negative electrode active material layer; 112. Negative electrode current collector layer; 1121. Burr; 1122. Electrode edge defect; 12. Solid electrolyte layer; 13. Positive electrode; 131. Positive electrode active material layer; 132. Positive electrode current collector layer; 1301. Misaligned protrusion; 1302. Misaligned depression; 20. Encapsulation structure; 21. Filling portion; 210. Permeation portion; 22. Coating portion;

[0036] 30. Hot pressing device; 31. Heating plate; 310. Heating tank; 311. Vibrating structure; 32. Pressure plate;

[0037] 41. Precision coating equipment for fluid materials; 42. Scanning module; 43. Control unit. Detailed Implementation

[0038] To provide a more detailed understanding of the features and technical content of the embodiments of this disclosure, the implementation of the embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this disclosure. In the following technical description, for ease of explanation, several details are used to provide a full 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 simplified in their depiction to simplify the drawings.

[0039] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure 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 used interchangeably where appropriate to understand the embodiments of this disclosure described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion.

[0040] In this disclosure, the terms "upper," "lower," "inner," "middle," "outer," "front," and "rear," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for better description of the embodiments of this disclosure and their implementations, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to require them to be constructed and operated in a specific orientation. Furthermore, some of the aforementioned terms may be used to indicate other meanings besides orientation or positional relationship; for example, the term "upper" may in some cases indicate a dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in the embodiments of this disclosure according to the specific circumstances.

[0041] Furthermore, the terms "set up," "connect," and "fix" should be interpreted broadly. For example, "connection" 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 a direct connection or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this disclosure according to the specific circumstances.

[0042] Unless otherwise stated, the term "multiple" means two or more.

[0043] In this embodiment of the disclosure, the character " / " indicates that the objects before and after it are in an "or" relationship. For example, A / B means: A or B.

[0044] The term "and / or" describes an association between objects, indicating that three relationships can exist. For example, A and / or B means: A or B, or A and B.

[0045] It should be noted that, unless otherwise specified, the embodiments and features described in the present disclosure can be combined with each other.

[0046] Combination Figures 1 to 4 As shown, this embodiment of the present disclosure provides a battery cell, including a stacked structure 10 and a packaging structure 20. The stacked structure 10 includes alternately stacked negative electrode plates 11 and positive electrode plates 13, and a solid electrolyte layer 12 is disposed between adjacent positive electrode plates 13 and negative electrode plates 11; the peripheral side of the stacked structure 10 forms laminations. The packaging structure 20 includes a filling portion 21 and a permeation portion 210. The filling portion 21 is disposed in the laminations of the stacked structure 10, and the permeation portion 210 is the portion of the filling portion 21 that extends and permeates into the interior of the laminations surrounding the laminations; the permeation depth of the permeation portion 210 is greater than or equal to 1 μm.

[0047] In the battery cell of this embodiment, the encapsulation structure includes, in addition to the filling portion 21 disposed in the gaps between the layers of the stacked structure 10, a permeation portion 210 that penetrates into the layers surrounding the gaps between the layers. The permeation portion 210 ensures the interfacial bonding effect between the encapsulation structure 20 and the layers of the stacked structure 10, improves the bonding strength between the encapsulation structure and the layers, and the permeation portion penetrates into the active material area of ​​the electrode sheet to enhance the cohesive force and has a certain deformation capability to adapt to the molding pressure of the stacked battery cell and the volume change of the active material (including the volume change caused by molding pressure and charging and discharging). This avoids the encapsulation structure from losing contact with the layers (electrode sheets and / or solid electrolyte layer) and excessive deformation leading to the generation of new edge stress, thereby improving the performance of the solid-state battery.

[0048] In the battery cell of this disclosure embodiment, the bonding strength between the packaging structure and the laminated structure reaches 1.2 MPa or higher. The first-cycle discharge specific capacity of the solid-state battery obtained by assembling the battery cell of this disclosure embodiment can be improved.

[0049] In the battery cell of this disclosure, "inside the layers" refers to the interior of the positive electrode, negative electrode, and solid electrolyte layer, and more specifically, the positive active material layer, negative active material layer, and solid electrolyte layer.

[0050] In the battery cell of this embodiment, the filling rate of the lamination gaps in the packaging structure 20 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%.

[0051] The battery cell of this disclosure embodiment is a stacked battery cell, which can be used as a cell for a solid-state battery. Optionally, the stacked structure 10 includes one or more stacked units, each stacked unit including a negative electrode 11, a solid electrolyte layer 12, and a positive electrode 13 stacked sequentially. When the stacked structure 10 includes multiple stacked units, the positive electrode 13 of one stacked unit is stacked with the negative electrode of the adjacent stacked unit through the solid electrolyte layer. That is, the stacked structure 10 is arranged in the manner of negative electrode 11 / solid electrolyte layer 12 / positive electrode 13 / solid electrolyte layer 12 / negative electrode 11 / solid electrolyte layer 12 / positive electrode 13 / ... Generally, the electrode plates on the two surfaces of the stacked structure 10 are negative electrode plates 11, but this is not a limitation.

[0052] In the battery cell of this embodiment, the layers include electrodes (positive electrode and negative electrode) and a solid electrolyte layer. The gaps between the electrodes are the gaps formed between the electrodes or between the electrode and the solid electrolyte layer. The gaps vary depending on the size of the electrodes. Optionally, the gaps include misalignment gaps and / or overhanging gaps. Misalignment gaps are caused by misalignment of the negative electrode, solid electrolyte layer, and positive electrode during stacking. Generally, misalignment gaps are generated when positive and negative electrodes of the same size are not aligned during stacking (see [link to relevant documentation]). Figure 3 (As shown). Among these, "equal-size design" generally refers to the active material region having the same area. The overhang gap is the gap (i.e., overhang) corresponding to the overhang region formed by at least one side of the negative electrode extending beyond the positive electrode in the circumferential direction. In this case, the negative electrode is designed to be larger than the positive electrode, so that at least one side of the negative electrode extends beyond the overhang region formed by the positive electrode (see...). Figure 1 and Figure 4 (As shown). Relative to the peripheral outer contour of the laminated structure 10, the misaligned gaps and / or overhanging gaps extend inwards towards the laminated structure 10, having a certain depth (see...). Figure 2 (as shown in d1) Stress concentration can easily occur under the molding pressure during solid-state battery assembly, leading to short circuits in the cells and reducing cell manufacturing yield and performance consistency. The encapsulation structure 20 fills these misaligned gaps and / or overhanging gaps, thereby solving the problem of stress concentration and short circuits caused by these gaps under molding pressure. Furthermore, the encapsulation structure also has a penetration portion 210 that penetrates into the layers surrounding the gaps. The penetration portion 210 ensures the interfacial bonding effect between the encapsulation structure 20 and the stacked structure 10, improving the bonding strength between the encapsulation structure and the layers.

[0053] In the battery cell of this embodiment, the permeation portion 210 of the encapsulation structure 20 permeates into the layers surrounding the gaps in the laminated structure 10. For example, the permeation portion 210 permeates into the active material of the positive electrode sheet surrounding the gaps in the laminated structure, the solid electrolyte layer, and the active material of the negative electrode sheet (see [link]). Figure 2 As shown in the figure, theoretically, the encapsulation material penetrating into the layers will cause the positive electrode 13 to lose part of its theoretical capacity. However, in practical applications, the setting of the permeation part 210 can not only improve the bonding strength between the encapsulation structure and the stacked structure and improve the cell yield, but also greatly improve the actual capacity of the cell, improve the first-cycle specific capacity and cycle performance of the battery, and thus improve the battery performance.

[0054] In some embodiments, the penetration depth d2 of the permeation portion 210 is greater than or equal to 1 μm. By controlling the penetration depth to balance theoretical capacity loss and actual capacity gain, battery performance can be improved. Optionally, the penetration depth of the permeation portion is greater than or equal to 1 μm and less than or equal to 300 μm. Optionally, the penetration depth of the permeation portion is greater than or equal to 10 μm and less than or equal to 300 μm. Optionally, the penetration depth of the permeation portion is greater than or equal to 50 μm and less than or equal to 300 μm. Optionally, the penetration depth of the permeation portion is greater than or equal to 100 μm and less than or equal to 300 μm. Optionally, the penetration depth of the permeation portion is greater than or equal to 150 μm and less than or equal to 300 μm. Optionally, the penetration depth of the permeation portion is greater than or equal to 200 μm and less than or equal to 250 μm. By controlling the penetration depth of the permeation portion, theoretical capacity loss is controlled, and battery performance can be better improved while ensuring bonding strength to provide cell yield.

[0055] In some embodiments, the percentage of the electrode area occupied by the permeated portion is less than or equal to 1%. That is, the percentage of the permeated area of ​​the permeated portion relative to the electrode area is less than or equal to 1%. In this embodiment, by controlling the percentage of permeation of the permeated portion, the theoretical capacity loss and the actual capacity improvement are balanced, thereby ensuring improved battery performance. Optionally, the percentage of the permeated area of ​​the permeated portion relative to the electrode area is less than or equal to 0.8%. In this embodiment, the area (or permeation area) of the permeated portion is calculated using the permeation depth of the permeated portion as one of the multipliers. For example, taking the positive electrode as an example, the permeation area of ​​the permeated portion is the product of the permeation depth of the permeated portion and the peripheral length of the positive electrode.

[0056] Optionally, the penetration depth d2 of the permeation portion is less than or equal to 300 μm, and the penetration area of ​​the permeation portion accounts for less than or equal to 1% of the area of ​​the electrode sheet.

[0057] The battery cells of this disclosure are more suitable for large-size battery cells. It is understood that the larger the battery cell size, the smaller the ratio of the penetration depth / penetration area of ​​the permeation portion to the electrode area, and the smaller the theoretical capacity loss. However, the bonding strength between the packaging structure and the stacked structure is not affected. While improving the cell yield, it can also greatly improve the actual capacity of the cell, improve the first-cycle specific capacity and cycle performance of the battery, and thus improve the battery performance.

[0058] In some embodiments, such as Figure 1 and Figure 4 As shown, the encapsulation structure 20 also includes a covering portion 22, which is connected to the filling portion 21 and covers the peripheral side surface of the stacked structure 10. By wrapping the peripheral side surface of the cell, defects left over from previous processes, such as electrode edge defects, foil burrs, and misalignment of the stacked wafers, are compensated. Furthermore, the fully enclosed outer frame encapsulation design protects the internal environment of the cell and can accommodate volume changes during cell operation, comprehensively improving the yield and safety performance of the cell manufacturing process. For example, the covering portion 22 can cover... Figure 4 The diagram shows burrs 1121 and electrode edge defects 1122 on the negative electrode current collector layer 112, as well as misalignment protrusions 1301 and misalignment depressions 1302 caused by misalignment of the stacked electrodes. Burrs can easily puncture the electrolyte membrane, leading to micro-short circuits at the positive and negative electrode contacts, causing battery self-discharge and degradation of electrochemical performance; in terms of safety, the local current density at the micro-short circuit exceeds 100 A / cm². 2 (far exceeding the normal charging and discharging capacity of 1~5 A / cm) 2 This will rapidly accumulate heat, and in severe cases, cause thermal runaway of the battery.

[0059] In the battery cell of this embodiment, the encapsulation structure 20 is obtained by distributing encapsulation material into the gaps between the wafer layers. The encapsulation material used in the encapsulation structure 20 can be the same material or different materials. For example, when the encapsulation structure 20 includes a filling portion 21, a permeation portion 210, and a covering portion 22, the filling portion 21 and the permeation portion 210 are made of the same material, while the covering portion 22 is made of a different material. It is understood that the filling portion 21 and the permeation portion 210 need to fill into the gaps between the wafer layers, and therefore need to use an encapsulation material with a certain degree of permeability to ensure that the encapsulation material can enter into the gaps between the wafer layers and permeate into the wafer layers. The covering portion 22 covers the peripheral side surface of the stacked structure 10, and therefore can use an encapsulation material without permeability.

[0060] Optionally, the packaging structure 20 uses the same packaging material. This allows for a single packaging process, simplifying the packaging procedure.

[0061] In some embodiments, the encapsulation material of the encapsulation structure 20 includes an insulating material, i.e. a non-conductive material, for example, the encapsulation material is selected from one or a combination of oxides, polymers, thermoplastic polymers and composite materials.

[0062] In some embodiments, the encapsulation material of the encapsulation structure 20 includes a resin material whose permeability varies with temperature. Generally, the higher the heating temperature of the resin material, the better its flowability and permeability. The flowability and permeability of the resin material can be adjusted by controlling the heating temperature of the resin material. Optionally, the encapsulation material includes a resin material whose permeability is positively correlated with temperature; that is, the higher the temperature (heating temperature), the better the flowability and the stronger the permeability of the resin material; conversely, the lower the temperature (heating temperature), the worse the flowability and the weaker the permeability of the resin material.

[0063] In some embodiments, the encapsulation material of the encapsulation structure 20 includes a hot-melt resin material.

[0064] In some embodiments, the encapsulation material of the encapsulation structure 20 includes a polymer containing one or more of the following polar functional groups: ester (-COO-), carboxyl (-COOH), anhydride (-C(O)OC(O)-), amide (-NHCO-), amino (-NH2), hydroxyl (-OH), and epoxy (-CH(O)CH-), etc. In this embodiment, the polymer can be an insulating material or a resin material, etc., without limitation, as long as it has at least one of the above polar functional groups. Polymers containing the above-mentioned specific polar functional groups can further improve the permeability of the encapsulation material, more effectively penetrate into the interior of the sheet, and contact and penetrate with the substances inside the sheet (e.g., the active material of the electrode, adhesive, etc.), thereby improving the bonding strength of the encapsulation structure.

[0065] Optionally, the encapsulation material of the encapsulation structure 20 includes a resin material containing one or more of the following polar functional groups whose permeability can change according to temperature: ester group (-COO-), carboxyl group (-COOH), acid anhydride group (-C(O)OC(O)-), amide group (-NHCO-), amino group (-NH2), hydroxyl group (-OH) and epoxy group (-CH(O)CH-), etc.

[0066] Optionally, the encapsulation material of the encapsulation structure 20 includes a hot-melt resin material containing one or more of the following polar functional groups: ester group (-COO-), carboxyl group (-COOH), acid anhydride group (-C(O)OC(O)-), amide group (-NHCO-), amino group (-NH2), hydroxyl group (-OH), and epoxy group (-CH(O)CH-), etc.

[0067] In some embodiments, the encapsulation material of the encapsulation structure 20 includes one or more mixtures of ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), polyethylene terephthalate (PET), and ethylene-acrylic acid copolymer (EAA).

[0068] The above-mentioned insulating materials, resin materials, polymers, and other encapsulation materials can be used individually. During use, they are heated and melted into a fluid state, giving them a certain degree of permeability. The molten encapsulation material is then placed in the gaps between the layers, partially penetrating into the interior of the layers, and solidified to form an encapsulation structure. The application method is not limited and can include coating, potting, etc.

[0069] The above-mentioned insulating materials, resin materials, polymers and other encapsulation materials can also be compounded with other auxiliary additives to form composite encapsulation materials to improve their encapsulation effect.

[0070] In some embodiments, the encapsulation material of the encapsulation structure 20 further includes auxiliary additives, which include one or more of compatibilizers, coupling agents, surfactants, and inorganic fillers. The types of compatibilizers, coupling agents, surfactants, and inorganic fillers are not limited, and can be found in subsequent related content.

[0071] In some embodiments, the encapsulation material further includes auxiliary additives, wherein the mass percentage of the auxiliary additives is 20% to 60%. Controlling the amount of auxiliary additives ensures the encapsulation effect. Optionally, the mass percentage of the auxiliary additives is 20% to 50%. Optionally, the mass percentage of the auxiliary additives is 20% to 40%. Optionally, the mass percentage of the auxiliary additives is 20% to 30%. When there are multiple auxiliary additives, the proportion of each auxiliary additive is not limited.

[0072] Optionally, when the auxiliary additives include organic additives such as compatibilizers, coupling agents, and surfactants, the organic additives include polymers containing one or more polar functional groups selected from ester, carboxyl, acid anhydride, amide, amino, hydroxyl, and epoxy groups. Organic additives containing the aforementioned specific polar functional groups can further improve the permeability of the encapsulation material and more effectively penetrate into the interior of the film.

[0073] For example, compatibilizers include, but are not limited to, maleic anhydride-grafted polyolefins (MAH-g-PO / PP / PE), epoxy-modified polyolefins, etc.; coupling agents include, but are not limited to, γ-aminopropyltriethoxysilane, etc.

[0074] This disclosure provides a hot-melt resin material, comprising, by weight: 40-80 parts of a matrix resin, 5-10 parts of a compatibilizer, 1-3 parts of a coupling agent, and 0-60 parts of an inorganic filler. The matrix resin comprises a polymer containing one or more polar functional groups selected from ester, carboxyl, anhydride, amide, amino, hydroxyl, and epoxy groups.

[0075] The hot-melt resin material in this embodiment has a melting point of 60–100 °C, a melt index of 200–400 g / 10 min, and a melt viscosity of 2000–12000 mPa·s; and a contact angle with the battery electrode surface of ≤60°.

[0076] The hot-melt resin material of this disclosure has adjustable flowability, permeability, and mechanical strength after curing. It can be reshaped under temperature and / or vibration, enhancing the interaction with active materials and binders within the electrode of the stacked structure 10, improving interfacial contact, and increasing the bonding force with the foil and active material areas. Simultaneously, the contact angle between the hot-melt resin material and the battery electrode surface is ≤60°, allowing for rapid spreading and filling of gaps in the electrode layers, and easier penetration into the interior of the layers. This enables contact and penetration with substances within the layers (e.g., active materials and binders of the electrode), improving the bonding strength of the encapsulation structure.

[0077] The hot-melt resin material of this disclosure is made by mixing the components and heating it to the melting point to make it fluid during use, thus giving it fluidity and permeability.

[0078] In some embodiments of the hot-melt resin material, the matrix resin is selected from one or more mixtures of ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylate copolymer (EEA), polyethylene terephthalate (PET), and ethylene-acrylic acid copolymer (EAA). In this embodiment, the type of matrix resin provides better surface contact with the positive and negative electrode active materials and the polymer binder, and facilitates penetration to form a stable contact.

[0079] Optionally, the matrix resin is 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts or 80 parts by weight, or any number of parts in the range of 40 to 80 parts.

[0080] In some embodiments of the hot-melt resin material, the compatibilizer is selected from one or more of maleic anhydride-grafted polyolefin (MAH-g-PP / PE), epoxy-modified polyolefin, and polypropylene-grafted polystyrene (PP-g-PS). In this embodiment, the type of compatibilizer provides better surface contact with the positive and negative electrode active materials and the polymer binder, and facilitates penetration to form a stable contact.

[0081] Optionally, the compatibilizer is provided in parts by weight of 5, 6, 7, 8, 9 or 10 parts, or any number of parts in the range of 5 to 10.

[0082] In some embodiments of the hot-melt resin material, the coupling agent includes a silane coupling agent. Optionally, the silane coupling agent is selected from one or more of γ-aminopropyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane. In this embodiment, the silane coupling agent has relatively high chemical stability to the solid electrolyte and will not cause a significant reduction in the electrolyte's ionic conductivity.

[0083] In some embodiments of the hot-melt resin material, the coupling agent includes a titanate coupling agent. Optionally, the titanate coupling agent is selected from isopropyl triisostearate titanate and / or isopropyl dioleoyloxytitanate. In this embodiment, the titanate coupling agent has relatively high chemical stability to the solid electrolyte and will not cause a significant reduction in the electrolyte's ionic conductivity.

[0084] Optionally, the coupling agent may be 1 part, 2 parts, or 3 parts by weight, or any number of parts within the range of 1 to 3 parts.

[0085] Optionally, the compatibilizer and / or coupling agent are selected from polymers containing one or more polar functional groups selected from ester, carboxyl, anhydride, amide, amino, hydroxyl, and epoxy groups. Compatibilizers and / or coupling agents containing the aforementioned specific polar functional groups can further improve the permeability of the encapsulation material and more effectively penetrate into the interior of the film. For example, compatibilizers include, but are not limited to, maleic anhydride-grafted polyolefins (MAH-g-PO / PP / PE), epoxy-modified polyolefins, etc.; coupling agents include, but are not limited to, γ-aminopropyltriethoxysilane, etc.

[0086] In some embodiments of the hot-melt resin material, the inorganic filler is selected from one or more of barium sulfate, titanium dioxide, talc, bentonite, quartz sand, alumina, calcium carbonate, glass powder, and zinc oxide. In this embodiment, the inorganic filler can increase the strength and filling capacity of the hot-melt resin material, and the type of inorganic filler in this embodiment can also achieve better surface contact with the positive and negative electrode active materials and polymer binders, making it easier to penetrate and form a stable contact.

[0087] In some embodiments of the hot-melt resin material, the particle size of the inorganic filler is 20-50 nm, and the inorganic filler is selected from one or more of barium sulfate, titanium dioxide, talc, bentonite, quartz sand, alumina, calcium carbonate, glass powder, and zinc oxide.

[0088] Optionally, the inorganic filler includes alumina nanoparticles with a particle size of 20–50 nm.

[0089] Optionally, the inorganic filler is 1 to 60 parts by weight. Optionally, the inorganic filler is 1 part, 5 parts, 10 parts, 20 parts, 30 parts, 40 parts, 50 parts or 60 parts, or any number of parts within the range of 1 to 60 parts.

[0090] Optionally, a hot-melt resin material comprises, by weight: 50-80 parts of matrix resin, 6-10 parts of compatibilizer, 2-3 parts of coupling agent, and 10-50 parts of inorganic filler.

[0091] Optionally, a hot-melt resin material comprises, by weight: 60-80 parts of matrix resin, 8-10 parts of compatibilizer, 2-3 parts of coupling agent, and 10-30 parts of inorganic filler.

[0092] Optionally, a hot-melt resin material comprises, by weight: 70 parts of matrix resin, 10 parts of compatibilizer, 3 parts of coupling agent, and 17 parts of inorganic filler.

[0093] In the battery cell of this embodiment, the encapsulation structure 20 is obtained by curing an encapsulation material. The permeability of the encapsulation material is positively correlated with its heating temperature; that is, the higher the heating temperature, the better the fluidity and permeability of the encapsulation material.

[0094] In the battery cell of this embodiment, the specific structure and composition of the negative electrode 11, the solid electrolyte layer 12 and the positive electrode 13 are not limited and can be determined according to the actual situation.

[0095] Optionally, a negative electrode sheet 11 includes a negative electrode active material layer 111 and a negative electrode current collector layer 112, with the negative electrode active material layer 111 disposed on the negative electrode current collector layer 112. The negative electrode active material layer 111 may be disposed on one or both sides of the negative electrode current collector layer 112, depending on actual requirements.

[0096] In this embodiment, the negative electrode current collector layer 112 is typically made of a metallic material. Optionally, the material of the negative electrode current collector layer 112 includes copper foil. The thickness of the negative electrode current collector layer 112 can be controlled between 6 and 10 μm; optionally, the thickness of the negative electrode current collector layer 112 is 6 to 8 μm. Optionally, the negative electrode current collector layer 112 includes copper foil with a thickness of 6 to 10 μm.

[0097] The negative electrode active material layer 111 is not limited and is determined according to actual needs. Optionally, the negative electrode active material layer 111 includes a negative electrode active material and other additives, which include one or more composites of components such as pure silicon materials, graphite materials, carbon materials, silicon-carbon materials, and silicon-oxygen materials.

[0098] Optionally, a negative electrode sheet includes a negative electrode active material layer. That is, the negative electrode sheet in this embodiment consists only of a negative electrode active material layer 111, which is designed to reversibly accommodate and release lithium ions and can serve as an external conductor, eliminating the need for a negative electrode current collector layer 112 to provide conductivity. In this case, the negative electrode active material layer 111 is composed of one or more composites of conductive materials such as lithium metal and carbon materials.

[0099] Optionally, a positive electrode 13 includes a positive active material layer 131 and a positive current collector layer 132, with the positive active material layer 131 disposed on the positive current collector layer 132. The positive active material layer 131 may be disposed on one or both sides of the positive current collector layer 132, depending on actual requirements.

[0100] In this embodiment, the positive electrode current collector layer 132 is typically made of a metallic material. Optionally, the material of the positive electrode current collector layer 132 includes aluminum foil. The thickness of the positive electrode current collector layer 132 can be controlled between 6 and 20 μm; optionally, the thickness of the positive electrode current collector layer 132 is 10 to 20 μm. Optionally, the positive electrode current collector layer 132 includes an aluminum foil with a thickness of 10 to 20 μm.

[0101] Optionally, the positive electrode active material layer 131 is mainly composed of one or more complexes selected from lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium manganese oxide, lithium nickel manganese oxide, lithium-rich manganese-based oxide, lithium manganese iron phosphate, lithium nickel cobalt aluminum oxide, lithium nickel cobalt manganese oxide, lithium iron phosphate, lithium vanadium phosphate, sulfur, lithium sulfide, and sulfur iodide.

[0102] In the battery cell of this embodiment, the solid electrolyte layer 12 connects the negative electrode active material layer 111 and the positive electrode active material layer 131 to each other, providing lithium-ion transport. The solid electrolyte layer 12 is obtained by combining one or more components such as sulfide electrolyte, oxide electrolyte, polymer electrolyte, and halide electrolyte. Preferably, the solid electrolyte layer 12 is a sulfide electrolyte, selected from one or more combinations of lithium phosphorus chloride sulfide, lithium phosphorus bromine sulfide, lithium phosphorus iodine sulfide, lithium phosphorus silicon sulfide, lithium phosphorus aluminum sulfide, lithium phosphorus germanium sulfide, lithium phosphorus boron sulfide, lithium phosphorus sulfide, lithium silicon sulfide, and lithium silicon indium sulfide.

[0103] Combination Figure 5 As shown in the figure, this disclosure provides a battery cell packaging method, including the following steps:

[0104] S110. The positive electrode, the negative electrode, and the solid electrolyte layer are stacked in the order of positive electrode, solid electrolyte layer, negative electrode, and solid electrolyte layer to obtain a stacked structure; wherein, the periphery of the stacked structure has laminations.

[0105] S120. An encapsulation material is disposed within the gaps between the layers of the stacked structure to obtain a battery cell with an encapsulation structure; wherein the encapsulation material can penetrate into the layers surrounding the gaps to form a permeated portion.

[0106] In the cell packaging method of this disclosure, a positive electrode sheet, a negative electrode sheet, and a solid electrolyte layer are first stacked in a specific order to obtain a stacked structure. Then, packaging material is placed into the gaps between the layers of the stacked structure. Compared with existing methods that require insulation treatment on a single layer (such as a positive electrode sheet), the cell packaging method of this disclosure is more practical. It can use continuously coated electrodes, is compatible with overhang designs and size-equal designs for positive and negative electrodes, and simplifies the edge short-circuit protection treatment of a single electrode sheet to edge short-circuit protection packaging of the stacked structure, greatly reducing the difficulty, cycle, and cost of battery manufacturing processes.

[0107] In the cell packaging method of this disclosure, in step S110, the positive electrode, solid electrolyte layer, and negative electrode can all be obtained using conventional methods, and are not limited thereto. The positive and negative electrode sizes can be equal, or the negative electrode can have an overhang design where at least one side of the circumferential direction is larger than that of the positive electrode.

[0108] In step S120, the method of placing the encapsulation material into the gaps between the layers of the laminated structure is not limited, as long as the encapsulation slurry can be placed in the gaps between the layers and penetrate into the surrounding layers. In some embodiments, placing the encapsulation material into the gaps between the layers of the laminated structure includes: placing the encapsulation material into the gaps between the layers of the laminated structure using a 3D printing method, a potting method, or a filling method.

[0109] Optionally, 3D printing can be used to print encapsulation material into the gaps between the layers of the stacked structure. Compared to other methods, edge encapsulation of stacked solid-state battery cells using 3D printing technology allows for precise control of the amount of material deposited. When introducing encapsulation material into the peripheral surfaces and gaps between the layers of the stacked structure, the appropriate amount of encapsulation material can be accurately delivered according to the needs of different locations. Simultaneously, the non-contact 3D printing manufacturing technology will not cause mechanical damage to the electrodes. Moreover, the 3D printing method can construct support structures within micron-level gaps, effectively ensuring the filling rate of interlayer gaps and allowing the encapsulation material to penetrate deep into the gaps and permeate into the surrounding layers, thus more effectively solving the edge stress concentration problem during solid-state cell pressurization or high-voltage operation. Furthermore, the 3D printing method has high processing efficiency and high material utilization, and can address both the permeability and overflow prevention issues of the fluid-like encapsulation material during printing. In this embodiment, the printing path and printing parameters in the 3D printing method are set according to actual conditions and are not limited.

[0110] In some embodiments, step S120, depositing an encapsulation material into the gaps between the layers of the laminated structure, includes: depositing a first permeable encapsulation material into the gaps between the layers of the laminated structure to obtain a first laminated structure with a first encapsulation layer; wherein the first encapsulation layer has a permeable portion penetrating into the layers surrounding the gaps between the layers and a first filling portion located in the gaps between the layers, the thickness of the first filling portion being less than the depth of the gaps between the layers. A second permeable encapsulation material is then deposited into the gaps between the layers of the first laminated structure to obtain a second encapsulation layer outside the first encapsulation layer, thus obtaining an encapsulated laminated structure; wherein the outer surface of the second encapsulation layer is flush with the peripheral side surface of the laminated structure, or the second encapsulation layer protrudes from the peripheral side surface of the laminated structure and forms a covering portion encapsulating the peripheral side surface of the laminated structure; and the permeability of the second permeable encapsulation material is less than the permeability of the first permeable encapsulation material.

[0111] The cell packaging method in this embodiment is defined as a dynamic control packaging method. First, a first permeable packaging material with better permeability is used for filling, so that the packaging material can penetrate into the surrounding layers of the layer gaps. Then, a second permeable packaging material with lower permeability is used to completely fill the layer gaps. This allows for controllable control of the depth of the packaging material penetrating into the layer, ensuring the interface bonding effect of deep penetration and avoiding edge overflow defects, thus forming a dense, non-porous packaging structure 20.

[0112] In this embodiment, the first permeable encapsulating material and the second permeable encapsulating material can be the same material or different materials. For example, both the first permeable encapsulating material and the second permeable encapsulating material can be the aforementioned hot-melt resin material.

[0113] The permeability of the first and second permeable encapsulating materials can be achieved by heating. Specifically, the first and second permeable encapsulating materials are resin materials whose permeability (flowability) changes with temperature. Optionally, the first permeable encapsulating material is an encapsulating material heated to a first temperature, and the second permeable encapsulating material is an encapsulating material heated to a second temperature, where the first temperature is higher than the second temperature. In this embodiment, the first and second temperatures are selected from temperature values ​​within the melting point range of the encapsulating materials. Optionally, the first temperature is selected from a first sub-temperature range within the melting point range of the encapsulating material, closer to the high-temperature end; the second temperature is selected from a second sub-temperature range within the melting point range of the encapsulating material, closer to the low-temperature end. The first and second sub-temperature ranges may partially overlap.

[0114] Optionally, the first permeable encapsulating material is obtained by heating the aforementioned hot-melt resin material to 80°C to 100°C; and / or, the first permeable encapsulating material is obtained by heating the aforementioned hot-melt resin material to 60°C to 85°C. That is, the aforementioned hot-melt resin material is heated to its melting point to melt it into a fluid.

[0115] In the dynamic control encapsulation method of this embodiment, the permeation performance of the encapsulation material is controlled during the encapsulation process. For example, the permeation performance of the encapsulation material is controlled by adjusting the temperature. Therefore, a device / equipment capable of controlling the discharge temperature can be used for encapsulation.

[0116] Optionally, a 3D printing method or a potting method can be used for dynamic control encapsulation. In this embodiment, a 3D printing device or a potting machine is used for dynamic control encapsulation.

[0117] In one example, a 3D printing device is used to dynamically control the encapsulation process by applying encapsulation material into the gaps between the layers of a stacked structure using a 3D printing method. The 3D printing device can be one with a single ejector head (e.g., a single-nozzle 3D printer) or multiple ejector heads (e.g., a multi-nozzle 3D printer). Optionally, a multi-nozzle 3D printer is used to dynamically control the encapsulation process by applying encapsulation material into the gaps between the layers of the stacked structure. A first ejector head (first print head) outputs a first permeable encapsulation material, and a second ejector head (second print head) outputs a second permeable encapsulation material. During the 3D printing process, the printing path and printing parameters (e.g., printing speed, layer height, linewidth, print head aperture, etc.) are determined based on the depth and width of the gaps between the layers and the actual encapsulation material, and are not limited to any specific parameters. For example, the printing speed can be 25–45 mm / s, the layer height 10 μm–30 μm, and the linewidth 80–120 μm.

[0118] In the 3D dynamic control encapsulation method of this embodiment, the printing paths of the first permeable encapsulation material and the second permeable encapsulation material can be the same or different. Optionally, the printing path of the first permeable encapsulation material is a loop trajectory, and the printing path of the second permeable encapsulation material is a straight trajectory.

[0119] In another example, a dispensing machine is used to apply encapsulating material into the gaps between the layers of a laminated structure via a dispensing method, achieving dynamic control of the encapsulation process. The dispensing machine can be one with a single dispensing head (e.g., a single-nozzle dispensing machine) or multiple dispensing heads (e.g., a multi-nozzle dispensing machine). Optionally, a multi-nozzle dispensing machine is used to apply encapsulating material into the gaps between the layers of the laminated structure for dynamic control of the encapsulation. A first dispensing head (first dispensing needle) is used to dispense a first penetrating encapsulating material, and a second dispensing head (second dispensing needle) is used to dispense a second penetrating encapsulating material. During the dispensing process, the dispensing parameters (e.g., dispensing speed, dispensing volume, dispensing head orifice diameter, etc.) are determined based on the depth and width of the gaps between the layers and the actual encapsulating material, and are not limited to any specific parameters.

[0120] Different ejector heads use different heating temperatures and are rotated in conjunction with the printing path. Different ejector heads can be connected to different barrels, which can contain different encapsulation materials. Initially, a high-permeability hot melt resin ejector head is used for printing / filling to strengthen the connection between the encapsulation structure and the edge of the battery cell. Subsequently, an ejector head connected to a low-permeability and low-flow hot melt resin material is used for processing to avoid edge dripping.

[0121] In some embodiments, step S120, depositing encapsulation material into the gaps between the layers of the laminated structure, includes depositing encapsulation material layer by layer into the gaps between the layers of the laminated structure. In this embodiment, a layered depositing method is used, which facilitates control over the thickness and uniformity of the encapsulation structure. This embodiment can be performed using 3D printing or infusion methods.

[0122] The layered configuration method of this embodiment can be combined with the aforementioned dynamic control encapsulation method, that is, the first permeable encapsulation material and the second permeable encapsulation material are both configured using the layered configuration method of this embodiment.

[0123] Optionally, the encapsulation material includes an encapsulation material whose permeability is positively correlated with temperature; then, the encapsulation material is placed into the gaps between the layers of the stacked structure, including: placing the encapsulation material layer by layer into the gaps between the layers of the stacked structure, and decreasing the heating temperature of the encapsulation material from the inner layer to the outer layer. This embodiment can be performed using a 3D printing method or a potting method. In this embodiment, when printing for the first time on the peripheral side of the stacked cell (i.e., the stacked structure), the hot melt material is heated at a higher temperature or a hot melt material with higher permeability is used to improve fluidity and thus better fill the gaps and permeation areas. When printing for thickening, the hot melt material is heated at a lower temperature or a hot melt material with lower permeability is used to reduce fluidity and prevent overflow. That is, the cell encapsulation method with dynamic temperature regulation can better achieve the permeation of the encapsulation structure 20 into the layers, and by regulating the fluidity of the encapsulation material by heating temperature, the permeation ability can be adjusted, thereby enabling controllable adjustment of the permeation depth of the permeation section 210 and ensuring the improvement of battery performance.

[0124] In the cell packaging method of this embodiment, step S120, while "setting packaging material into the gaps between the layers of the stacked structure", also includes: acquiring permeation information that reflects the permeation of the packaging material; and adjusting the permeation capacity of the packaging material according to the permeation information. In this embodiment, by providing real-time feedback on the permeation of the packaging material, adaptive regulation of the permeation capacity (flowability) of the packaging material is achieved, which can effectively control the penetration depth of the packaging material, thereby ensuring the improvement of battery performance.

[0125] Optionally, the penetration information reflecting the penetration of the first permeable encapsulating material includes infrared imaging information. This embodiment uses infrared imaging to monitor the flow state and path of the encapsulating material (hot-melt resin material) in real time, dynamically adjusting the heating temperature.

[0126] In the encapsulation method of this disclosure embodiment, during the process of setting the encapsulation material in the gap between the layers, the encapsulation material begins to cool down and solidify. After the encapsulation is completed, the encapsulated stacked structure (the stacked structure with the encapsulation material) is left to stand for a period of time to solidify and form a cell with an encapsulation structure.

[0127] In some embodiments, after "setting encapsulation material in the gap area of ​​the stacked structure" in step S120, the method further includes a step of hot-pressing the stacked structure with encapsulation material. This embodiment performs hot-pressing on the stacked structure with encapsulation material to strengthen the bond between the encapsulation material (e.g., hot-melt resin material) and the electrode edge cavity, refilling microscopic depressions on the electrode surface (e.g., cracks <5 μm), and reducing interface void ratio. Simultaneously, by adding this hot-pressing step, the contact between solid-solid interfaces in the cell can be improved, thereby alleviating lithium dendrite growth problems and shortening ion transport paths by repairing poor contact interfaces. The hot-pressing process in this embodiment can be defined as a secondary curing process.

[0128] Optionally, the stacked structure containing the encapsulation material is subjected to hot pressing treatment, including: placing the stacked structure containing the encapsulation material on a heating plate at a first preset temperature and processing for a first preset time. The hot pressing treatment in this embodiment is referred to as the first type of hot pressing treatment, wherein the pressure is the self-pressure of the stacked structure containing the encapsulation material.

[0129] Optionally, the stacked structure containing the encapsulation material is subjected to hot pressing treatment, including: placing the stacked structure containing the encapsulation material on a heating plate at a first preset temperature, applying vibration, and processing for a second preset time. The hot pressing treatment in this embodiment is referred to as the second hot pressing treatment.

[0130] Optionally, the stacked structure containing the encapsulation material is subjected to hot pressing treatment, including: placing the stacked structure containing the encapsulation material on a heating plate at a first preset temperature, applying pressure, and processing for a second preset time. The hot pressing treatment in this embodiment is referred to as the third hot pressing treatment.

[0131] Optionally, the stacked structure containing the encapsulation material is subjected to hot pressing treatment, including: placing the stacked structure containing the encapsulation material on a heating plate at a first preset temperature, applying pressure and vibration, and processing for a second preset time. The hot pressing treatment in this embodiment is referred to as the fourth type of hot pressing treatment.

[0132] In the first to fourth hot-pressing processes, the first preset temperature is sufficient to soften the encapsulation material again, giving it a certain degree of fluidity. It is understood that a heating groove is provided on the heating plate, and the groove's body conforms to the outer contour of the stacked structure containing the encapsulation material. When the stacked structure containing the encapsulation material is placed inside the heating groove, the inner wall of the groove can confine the stacked structure, thus preventing slippage and misalignment of the layers under pressure, and also preventing the reheated and softened encapsulation material from flowing out of the gaps between the layers. Optionally, the first preset temperature is greater than or equal to T. min And less than or equal to T′, T′=T min +δ×(T max -T min ), where T max T represents the upper limit of the melting point range of the encapsulation material. min The lower limit of the melting point range of the encapsulation material is δ, which ranges from [0, 1 / 3]. The specific value of δ is determined based on the melting point range of the encapsulation material. That is, the first preset temperature is the lower limit of the melting point range of the encapsulation material or a certain temperature above the lower limit, which allows the encapsulation material to soften and have a certain degree of fluidity. Optionally, δ can be 0, 1 / 5, 1 / 4, or 1 / 3, etc.

[0133] Optionally, the first preset temperature is 60℃~70℃. Optionally, the first preset temperature is 60℃.

[0134] Optionally, the first preset time is 20s~60s. Optionally, the first preset time is 20s~50s. Optionally, the first preset time is 20s~40s. Optionally, the first preset time is 30s.

[0135] Optionally, a hot-pressing device is used to hot-press the laminated structure containing the encapsulation material, see [link to relevant documentation]. Figure 7 As shown, a hot pressing device 30 includes a heating plate 31 and a pressure plate 32. The heating plate 31 is provided with a heating groove 310, the cavity of which is consistent with the outer contour of the stacked structure on which the encapsulation material is disposed. The pressure plate 32 is movably disposed above the heating plate 31 and can be fastened to the heating plate 31 to apply pressure to the stacked structure placed in the heating groove 310.

[0136] Optionally, the bottom of the heating tank 310 is provided with a buffer structure. This provides flexible support for the stacked structure containing encapsulation material placed within the heating tank 310, protecting the stacked structure. In this embodiment, the buffer structure can be a buffer pad, such as a rubber pad, silicone pad, latex pad, or other elastically deformable buffer pad. Alternatively, it can be a support plate structure connected to the bottom wall of the heating tank 310 via a damping element, which can be a spring.

[0137] Optionally, the pressure plate 32 has a pressure protrusion on its pressure surface that is adapted to the shape of the heating tank 310, for directly pressurizing the stacked structure placed in the heating tank 310.

[0138] Optionally, a pressure sensor is provided on the pressure plate 32 to provide real-time feedback on the pressure applied to the laminated structure, ensuring that appropriate pressure is applied. Optionally, the pressure sensor is located on a pressure protrusion on the pressure surface of the pressure plate 32.

[0139] During hot pressing, appropriate pressure is applied to promote the flow and filling of the encapsulation material, and to promote the interaction between the encapsulation material and the active substances and binders in the electrode, thereby improving the bonding force.

[0140] Alternatively, the pressure can be applied by applying a constant pressure or by applying a gradient pressure.

[0141] Optionally, the constant pressure is selected from 0.3 to 0.5 MPa.

[0142] Optionally, the gradient pressure is applied by increasing the pressure gradient. Optionally, the pressure range of the gradient pressure is 0.3~3MPa. Optionally, applying the gradient pressure includes: applying a low pressure of 0.3~0.5MPa for a first preset time, and then increasing the pressure to a high pressure of 1~3MPa for a first preset time.

[0143] During hot pressing, vibration is added to further induce the encapsulation material to penetrate into the pores at the edge of the electrode sheet, increasing the interfacial adhesion strength and preventing breakage and material loss due to uneven stress in the edge material area. Optionally, when vibration is applied, the vibration includes vibration with a frequency of 10~50 Hz and an amplitude of less than or equal to 50 μm.

[0144] Optionally, when vibration is applied, the vibration includes: gradient step vibration. In this embodiment, gradient step vibration is applied by increasing the vibration frequency gradient. Optionally, in this embodiment, the gradient step vibration range is 20Hz to 2000Hz, and the gradient step vibration is performed from low frequency to high frequency within this range.

[0145] Optionally, gradient step vibration is applied, including: processing a first preset time under low-frequency vibration of 20 Hz to 50 Hz, and then processing a first preset time under high-frequency vibration of 500 Hz to 2000 Hz.

[0146] Optionally, the hot pressing device 30 further includes a vibration structure 311 for applying vibration to the stacked structure disposed on the heating plate 31. The form of the vibration structure is not limited, and the vibration structure 311 is disposed on the heating plate 31 to apply vibration to the stacked structure placed in the heating tank 310.

[0147] Optionally, the vibration structure 311 includes a flexible vibrating disc disposed within the heating groove of the heating plate 31, or the heating plate 31 is disposed on the flexible vibrating disc. The flexible vibrating disc includes a vibrating disc with a buffer structure on its surface. This makes the output vibration gentle and protects the laminated structure.

[0148] Optionally, the flexible vibratory feeder includes a flexible feeder body and a vibrating element. The vibration output end of the vibrating element is disposed on the flexible feeder body to output vibration to the flexible feeder body; the surface of the flexible feeder body has a buffer structure. In this embodiment, the vibration output object is a laminated battery cell structure, and the vibrating element is an element capable of outputting micro-vibrations such as small amplitude / small vibration frequency.

[0149] Optionally, the vibration element includes an electromagnetic vibration table, a piezoelectric vibrator, a spring vibration device, a pneumatic vibrator, a hydraulic vibrator, an ultrasonic device, etc. These vibration elements are capable of outputting micro-vibrations.

[0150] Optionally, the buffer structure on the surface of the flexible disc can be a buffer pad, such as a rubber pad, silicone pad, latex pad, or other elastically deformable buffer pad. Alternatively, it can be a support plate structure connected to the bottom wall of the heating tank 310 via a damping element, which can be a spring.

[0151] Optionally, the stacked structure containing the encapsulation material is subjected to hot pressing treatment, including: applying a low pressure of 0.3~0.5MPa and a low frequency vibration of 20 Hz~50 Hz to the stacked structure containing the encapsulation material for a first preset time, and then increasing the pressure to a high pressure of 1~3MPa and a high frequency vibration of 500Hz~2000Hz for a first preset time.

[0152] In one example, such as Figure 6 As shown, a 3D printing temperature-controlled encapsulation method includes:

[0153] S210. The positive electrode, the negative electrode, and the solid electrolyte layer are stacked in the order of positive electrode, solid electrolyte layer, negative electrode, and solid electrolyte layer to obtain a stacked structure; wherein, the periphery of the stacked structure has laminations.

[0154] S220. The stacked structure is vertically positioned in the printing area of ​​the 3D printing equipment with the side to be printed facing upwards.

[0155] S230. Obtain the outline entity data of the side of the stacked structure to be printed; obtain the outline 3D model based on the outline entity data; slice the outline 3D model, perform path planning and printing parameter design, and obtain printing information;

[0156] The S240 3D printing equipment prints molten encapsulation material heated to a preset temperature onto the side to be printed based on the printing information and the heating temperature of the encapsulation material, thus completing the encapsulation printing of the side to be printed of the stacked structure and obtaining a stacked structure with encapsulation material.

[0157] In this embodiment, the side to be printed of the laminated structure is one of the peripheral sides of the laminated structure. The above steps are repeated to encapsulate and print each side one by one to complete the encapsulation of the laminated structure.

[0158] In step S230 of this embodiment, the solid contour data of the side to be printed includes data that can represent key structural nodes such as edges, layers, and gaps between layers of 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 using a high-precision vision scanner or a 3D scanner, and simultaneously obtaining the solid contour data of the side to be printed by combining the solid parameters of the laminated structure. The solid parameters of the laminated structure include the dimensions of the laminated structure, the number of laminated layers, etc. Since the side of the laminated structure is not flat and has gaps between layers, the solid contour data includes 3D solid data.

[0159] In step S230, obtaining the 3D contour model based on the contour entity data includes: importing the entity contour data of the side to be printed into 3D modeling software, modeling, and obtaining the 3D contour model. The 3D modeling software is not limited; for example, MeshLab, Blender, etc. During the modeling process, the entity contour data can be processed, including noise removal, hole filling, mesh optimization, etc., without limitation.

[0160] Optionally, in step S230, the 3D contour model is sliced ​​using slicing software. The slicing software generates printing information based on the model's shape, size, and printing parameters. Printing parameters include layer height, infill density, printing speed, print head temperature, and print bed temperature. Printing information includes the printing path and printing parameters. The printing path determines the print head's movement trajectory, and the printing parameters include printing speed, material extrusion rate, layer height, material heating temperature, and print head temperature. The printing path is output in the form of G-code instructions recognizable by the 3D printing equipment.

[0161] Alternatively, slicing software includes Cura, PrusaSlicer, etc.

[0162] It is understandable that the periphery of the stacked structure includes four sides in different directions, each of which is a side to be packaged.

[0163] Optionally, if the solid contour data of the side to be printed obtained in step S230 is the solid contour data of the currently upward-facing side to be printed in step S220, then the printing path obtained in step S230 is the printing path of the currently upward-facing side to be printed; the 3D printing temperature control encapsulation method further includes: repeating steps S220 to S240 to encapsulate and print each side to be printed of the stacked structure, completing the encapsulation of the stacked structure; and obtaining the encapsulated stacked structure. In this embodiment, in step S220, when encapsulating different sides to be printed, it is necessary to adjust the upward-facing side to be printed. For example, rotate the stacked structure so that the side to be printed faces upward.

[0164] Optionally, if the solid contour data of the side to be printed obtained in step S230 is the solid contour data of the entire circumferential side of the stacked structure in step S210, then the printing path obtained in step S230 is the printing path of all the sides to be printed on the entire circumferential side. Therefore, when encapsulating different sides to be printed, simply adjust the current side to be printed to face upwards. For example, rotate the stacked structure so that the side to be printed faces upwards.

[0165] Optionally, step S240 further includes: simultaneously regulating the heating temperature of the encapsulation material. Specifically, simultaneously regulating the heating temperature of the encapsulation material includes: adjusting the heating temperature of the encapsulation material based on the obtained permeation information that reflects the permeation status of the encapsulation material. In this embodiment, by providing real-time feedback on the permeation status of the encapsulation material, adaptive regulation of the heating temperature (i.e., permeability and fluidity) of the encapsulation material is achieved, which can effectively control the penetration depth of the encapsulation material, thereby ensuring improved battery performance.

[0166] In some embodiments, the 3D printing temperature-controlled encapsulation method further includes: step S250, hot-pressing the stacked structure with encapsulation material. In this embodiment, the details of the hot-pressing process are as described above and will not be repeated here.

[0167] In the battery cell packaging method of this disclosure embodiment, after packaging is completed, for example after step S240 or step S250, the stacked structure with packaging material can be compressed, for example, isostatic pressing, so that the layers in the stacked structure are pressed together and connected to each other.

[0168] In the encapsulation method of this disclosure, the operation of placing the stacked structure on a 3D printing device and placing the printed stacked structure with encapsulation material on a hot pressing device can be done manually or through an automated conveying device, depending on the actual situation.

[0169] Combination Figure 8 As shown, this disclosure provides a battery cell packaging system for implementing the battery cell packaging method of any of the foregoing embodiments, including:

[0170] Fluid material precision coating equipment 41. Fluid material precision coating equipment 41 includes 3D printing equipment or dispensing machine.

[0171] A conveying and positioning module (not shown) is used to flip the completed stacked structure vertically and then convey it to the working area of ​​the fluid material precision coating equipment 41. Here, the working area refers to the area where coating is performed, such as the printing area of ​​a 3D printer or the dispensing area of ​​a glue dispensing machine.

[0172] Scanning module 42 is used to scan the outline entity data of the side of the stacked structure to be printed, which is set in the working area of ​​the fluid material precision coating equipment 41.

[0173] The control unit 43 obtains a three-dimensional contour model based on the contour entity data; slices the three-dimensional contour model, performs path planning and coating parameter (e.g., printing parameters) design, and obtains coating information (e.g., printing path and printing parameters).

[0174] The fluid material precision coating apparatus 41 receives coating information (e.g., printing path and printing parameters) from the control unit 43, and applies (e.g., printing or pouring) molten encapsulation material heated to a preset temperature onto the side of the stacked structure to be printed in the working area, according to the coating information. This allows the encapsulation material to penetrate into the interior of the layers around the gaps in the layers, forming a penetration portion. Thus, an encapsulation structure 20 is formed on the peripheral side of the stacked structure 10.

[0175] The packaging system in this embodiment automates the transfer between the wafer stacking process and the 3D printing equipment by incorporating a transfer and positioning module, thus achieving automation of the packaging system. The specific structure of the transfer and positioning module is not limited; for example, it may include a robotic arm.

[0176] Optionally, the conveying and positioning module includes a robotic arm, the end effector of which includes a flexible gripper for gripping the stacked structure. The flexible gripper refers to a gripper with a buffer structure on its gripping surface. Optionally, the buffer structure can be a buffer pad, such as a rubber pad, silicone pad, latex pad, or other elastically deformable buffer pad. This provides a certain buffering force during gripping, protecting the stacked structure.

[0177] Optionally, the flexible fixture can rotate relative to the main body of the robot arm. This allows the flexible fixture to rotate while the main body of the robot arm remains stationary, thereby rotating the stacked structure and adjusting the orientation of different printing sides of the stacked structure during the packaging process. In this embodiment, the method by which the flexible fixture can rotate relative to the robot arm is not limited.

[0178] Optionally, the scanning module 42 employs a high-precision vision scanner.

[0179] In the battery cell packaging system of this embodiment, the coating information obtained by the control unit 43 includes the coating path and coating parameters. Optionally, the control unit 43 can be used to perform the aforementioned step S230 to obtain printing information including the printing path and printing parameters.

[0180] In some embodiments, the fluid material precision coating equipment 41 includes a 3D printing device, and the coating information obtained by the control unit 43 includes a printing path and printing information; the printing information includes one or more of the following: a loop trajectory and / or a straight trajectory; a line width of 80 to 120 μm; a layer height of 5 to 20 μm; a printing speed of 25 to 45 mm / s; a heating temperature within the melting point range of the encapsulation material; and a print head temperature 1 to 50°C higher than the heating temperature;

[0181] Optionally, when the encapsulation material is the aforementioned hot-melt resin material, the heating temperature in the printed information is 60–100 °C.

[0182] Optionally, when the cell packaging system implements the aforementioned dynamically controlled packaging method, the heating temperature includes a first heating temperature and a second heating temperature, with the first heating temperature being greater than the second heating temperature; the first heating temperature is the heating temperature of the first permeable packaging material, and the second heating temperature is the heating temperature of the second permeable packaging material. For example, the first heating temperature is selected from 80℃ to 100℃, and the second heating temperature is selected from 60℃ to 100℃.

[0183] Optionally, when the battery cell packaging system implements the aforementioned dynamic control packaging method, the printing information may also include a printing temperature curve, and the heating temperature and the corresponding print head temperature are adjusted synchronously according to the printing temperature curve.

[0184] In some embodiments, the battery cell packaging system further includes a thermoforming device (such as...). Figure 7 As shown, the hot pressing device is used to perform hot pressing on the stacked structure with encapsulation material; the conveying and positioning module is also used to convey the printed stacked structure with encapsulation material to the hot pressing device for hot pressing.

[0185] In some embodiments, the delivery and positioning module is also used to deliver the packaged battery cell with the packaged structure to subsequent processes.

[0186] Understandably, the robotic end effector of the transfer and positioning module can also include a suction cup. After the stacked structure is packaged, the suction cup or other picking end effector can be used to pick up and transfer the packaged stacked structure, facilitating transfer.

[0187] In some embodiments, the battery cell packaging system further includes an infrared scanning device for performing infrared imaging scanning and monitoring of the gaps between the layers while the packaging material is being disposed within the gaps of the stacked structure, in order to obtain infrared imaging image information that reflects the permeation of the packaging material.

[0188] The following specific embodiments illustrate the battery cell and its packaging method, packaging system, solid-state battery, and hot-melt resin material of this disclosure, to more clearly explain the technical problems solved, technical solutions, and beneficial effects of this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this application or its applications.

[0189] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0190] Example 1

[0191] A battery cell includes a laminated structure and a packaging structure. The laminated structure includes alternately stacked negative and positive electrode sheets, with a solid electrolyte layer disposed between adjacent positive and negative electrode sheets. The negative electrode sheet extends beyond the positive electrode sheet on at least one side in the circumferential direction, forming an overhang region. A corresponding overhang gap is formed on the peripheral side of the laminated structure. The packaging structure includes a filling portion, a permeation portion, and a covering portion. The filling portion is disposed in the overhang gap of the laminated structure. The permeation portion extends from the filling portion into the layers surrounding the overhang gap. The covering portion is connected to the filling portion and covers the peripheral side of the laminated structure.

[0192] See Figure 1 and Figure 2 As shown, the battery cell of this embodiment 1 includes multiple stacked units, and the two surfaces of the stacked structure 10 are negative electrode plates.

[0193] In the battery cell of this embodiment 1, the encapsulation structure is formed by filling the overhanging gaps with molten hot-melt resin material, partially penetrating into the electrode layers, and then curing. The hot-melt resin material, by weight, includes: 70 parts of matrix resin, 10 parts of compatibilizer, 3 parts of coupling agent, and 17 parts of inorganic filler. The matrix resin is ethylene-vinyl acetate copolymer (EVA), the compatibilizer is maleic anhydride-grafted polyolefin (MAH-g-PP / PE), the silane coupling agent is γ-aminopropyltriethoxysilane, and the inorganic filler is 20-50 nm alumina nanoparticles. The melting point of this hot-melt resin material is 60-100 °C, the melt index is 200-400 g / 10 min, the melt viscosity is 2000-12000 mPa·s, and the contact angle with the battery electrode surface is ≤60°.

[0194] In this embodiment 1, for subsequent solid-state battery assembly and battery performance testing, the following negative electrode, positive electrode and solid electrolyte layer were specifically used.

[0195] Negative electrode sheet: The negative electrode active material layer is prepared using a wet process, and its composition is micron-sized silicon:PVDF:VGCF = 95:3:2 by mass ratio; the negative electrode current collector layer uses 6~10 μm copper foil; the size of the negative electrode sheet is 152mm×152mm. PVDF is polyvinylidene fluoride; VGCF is vapor-grown carbon fiber.

[0196] Positive electrode: The positive electrode active material layer is prepared using a dry process, and its composition is NCM:LPSCl:SP:PTFE = 85:10:3:2 by mass. The positive electrode current collector layer uses 10~20 μm aluminum foil. The size of the positive electrode is 148 mm × 148 mm. NCM refers to lithium nickel cobalt manganese oxide, LPSCl is a sulfide-germanium ore type electrolyte, SP is conductive carbon black, and PTFE is polytetrafluoroethylene.

[0197] The solid electrolyte layer is a sulfide electrolyte, selected from one or more of lithium phosphorus chlorine sulfide, lithium phosphorus bromine sulfide, lithium phosphorus iodine sulfide, lithium phosphorus silicon sulfide, lithium phosphorus aluminum sulfide, lithium phosphorus germanium sulfide, lithium phosphorus boron sulfide, lithium phosphorus sulfide, lithium silicon sulfide, and lithium silicon indium sulfide.

[0198] The battery cell in this embodiment 1 is packaged using a 3D temperature-controlled packaging method, which includes the following steps:

[0199] Stacking operation: A 6-positive-7-negative design is adopted. The positive electrode, the negative electrode, and the solid electrolyte layer are stacked in the order of positive electrode, solid electrolyte layer, negative electrode, and solid electrolyte layer to obtain a stacked structure. Among them, the negative electrode extends beyond the positive electrode in the circumferential direction to form an overhang region. The peripheral side of the stacked structure forms the overhang region corresponding to the overhang region. The width of the overhang region is 2mm.

[0200] The stacked structure is vertically positioned in the printing area of ​​the 3D printing equipment with the side to be printed facing upwards.

[0201] Constructing the printing path: A high-precision vision scanner (accuracy ±5 μm) is used to visually scan the side of the laminated structure to be printed, identifying the location of the layer gaps (the width of the layer gaps is approximately 200~300 μm). Simultaneously, combined with the solid parameters of the laminated structure (including the dimensions of the laminated structure and the number of laminated layers), the solid contour data of the side to be printed is obtained. The solid contour data of the side to be printed is imported into 3D modeling software to create a 3D contour model. The 3D contour model is sliced ​​using slicing software, which generates printing information based on the shape, size, and printing parameters of the model. The printing information includes the printing path and printing parameters. The printing path includes the movement trajectory of the print head, printing parameters such as printing speed, material extrusion rate, printing layer height, material heating temperature, and print head temperature. The movement trajectory includes loop trajectories and / or straight trajectories.

[0202] Printing and Encapsulation: Based on the printing information and the heating temperature of the encapsulation material, the 3D printing equipment uses a non-contact hot melt nozzle (100 μm aperture) to set the printing temperature to 85 ℃ (i.e., the heating temperature of the encapsulation material) and the initial extrusion pressure to 0.4 MPa. Along the side of the stacked structure, following the planned printing path and printing parameters (e.g., a loop or straight path, linewidth of 80–120 μm, layer height of 20 μm, and printing speed of 25–45 mm / s), it fills the gaps between the layers. The extrusion pressure and path are dynamically adjusted according to the model design until the gaps are filled, ultimately forming a covering layer approximately 40 μm thick on one side of the stacked structure (i.e., the thickness of the covering portion), completing the encapsulation of one side of the stacked structure. The stacked structure is rotated so that the side to be printed faces upwards, and the aforementioned steps are repeated to encapsulate each side of the stacked structure individually, obtaining a stacked structure with encapsulation material.

[0203] Hot pressing: Transfer the laminated structure to the hot pressing device 30 (e.g., Figure 7(As shown) Apply a pressure of 0.4 MPa, heat at 60 ℃ for 30 s, and simultaneously start the vibration structure 311 (e.g., frequency 30 Hz, amplitude 30 μm) to promote resin penetration. After completion, continue to pressurize to 2 MPa, adjust the vibration structure 311 to high frequency operation mode (e.g., 2 kHz), and continue hot pressing at high frequency for 30 s.

[0204] After hot pressing and cooling, the battery cell is obtained.

[0205] The packaging method in this embodiment 1 can be as follows: Figure 8 The packaging system shown.

[0206] Figure 9a This is a cross-sectional scanning electron microscope image of the battery cell in Example 1 of this embodiment. Figure 9b This is an EDS elemental analysis photograph of a cross-section of the battery cell in Example 1 of this embodiment. Figure 9a and Figure 9b It is evident that the penetration depth of the molten resin material reaches 200μm~300μm. CT scans show that the fill rate of the lamination voids reaches 91.5%. The resin-electrode interface bonding force measured using a tensile tester is 1.2 MPa (compared to 0.7 MPa for the traditional impregnation process). After encapsulation, the cell was tested under 20 MPa pressure for 24 hours, and no cracks were found at the electrode edges.

[0207] In the battery cell of this embodiment 1, the positive electrode sheet has a size of 148 mm × 148 mm, and the maximum penetration depth is 300 μm. Assuming that the penetrated positive electrode portion loses all capacity, the single-layer failure area is 177.6 mm². 2 This represents 0.81% of the total area of ​​the single-layer positive electrode. This indicates that even if the adhesive penetrates into the electrode, the theoretical capacity reduction is only 0.81%, far less than the actual capacity increase brought about by the encapsulation structure. As the electrode size increases, the failure area percentage will further decrease, making the embodiments of this disclosure particularly suitable for large-size cells. Therefore, by improving the penetration of the hot-melt encapsulation material into the layers, especially into the electrode active material and the solid electrolyte layer, through material design, vibration assistance, and other measures, the stability of the encapsulation structure is significantly improved.

[0208] In this embodiment 1, the processing time for 3D printing packaging of a single side (i.e., one side to be printed) is less than 1 minute, and the processing time for a single battery cell is 10 minutes (including printing and hot pressing). This is more than 3 times more efficient than the traditional electrode sheet processing process, and the material utilization rate reaches 95%. This is a significant improvement compared to the traditional spraying process, which has a material utilization rate of only 60% to 70%. Furthermore, traditional spraying and impregnation processes are difficult to control the gradient viscosity and quickly switch materials to balance penetration and on-site molding to prevent overflow.

[0209] Example 2

[0210] Compared to Example 1, the difference is that in one of the battery cells of Example 2, the negative electrode and the positive electrode are the same size, there is no overhang area design, and the periphery of the stacked structure forms misalignment gaps caused by the misalignment of the electrodes. Specifically, the negative electrode has a size of 148 mm × 148 mm, and the positive electrode has a size of 148 mm × 148 mm. The remaining steps and parameters are the same as in Example 1.

[0211] The cell structure of this embodiment 2 is shown below. Figure 3 As shown, the encapsulation structure is mainly used to wrap the burrs generated in the die-cutting process of the negative electrode current collector layer 112 or the positive electrode current collector layer 132, or to fill the misalignment gaps generated in the stacking process, and to penetrate into the layers to improve the bonding strength and prevent the insulation layer from separating from the cell under high pressure.

[0212] Example 3

[0213] The difference compared to Example 1 is that the combination Figure 4 As shown, in this embodiment 2, the positive and negative electrode sheets in the battery cell are made of electrode sheets with obvious defects for cell assembly. Typical electrode sheet defects include burrs generated during current collector die cutting, electrode edge defects such as missing material or cracks at the electrode edge, uneven thickness at the electrode edge causing local pressure imbalance during pressurization, resulting in electrode warping or breakage, and discontinuous coating also causing uneven current density distribution in the edge region. Local high current areas will accelerate polarization, affect charge and discharge efficiency, and may lead to the formation of lithium dendrites. Local exposure of the current collector may also lead to internal short circuits. The remaining steps and parameters are the same as in embodiment 1.

[0214] The positive and negative electrode sheets used in this embodiment 3 are those that would be discarded after screening in normal production. In this embodiment 3, these electrode sheets with obvious defects are used for cell assembly. At the same time, obvious misalignment defects are set in the stacking process. Other processes are consistent with normal cells. The packaging structure fills the misalignment protrusions 1301 and misalignment depressions 1302 caused by the misalignment, wraps the burrs 1121 of the current collector, and fills the edge defects 1122 of the electrode sheets, thereby greatly improving the survival rate of solid-state cells and improving the cell production yield and performance consistency.

[0215] Example 4

[0216] Compared to Example 1, the difference lies in the 3D temperature-controlled packaging method for the battery cell in Example 4. The 3D printing equipment used is a dual-needle 3D printing device with two independently temperature-controlled needles. The first needle (150 μm aperture) is connected to a high-permeability resin cylinder with a formulation of EVA:MAH-g-PP / PE:γ-aminopropyltriethoxysilane:alumina = 70:10:3:17 (same as the hot-melt resin material in Example 1). The heating temperature is a gradient decreasing temperature from 95 ℃ to 85 ℃, and the extrusion pressure is a gradient decreasing pressure from 0.6 MPa to 0.3 MPa. The printing path for the layer voids is planned as a loop trajectory with a linewidth of 120 μm, a layer height of 20 μm, and a printing speed of 45 mm / s. The second needle (100 μm aperture) is connected to a low-flowability resin cylinder with the same formulation. The heating temperature is a gradient decreasing temperature from 85 ℃ to 75 ℃, and the extrusion pressure is constant at 0.3 MPa. The pressure is MPa, the overprinting path is planned as a straight trajectory, the line width is 80 μm, the layer height is 20 μm, and the printing speed is 25 mm / s. The remaining steps and parameters are the same as in Example 1.

[0217] In the battery cell packaging method of this embodiment 4, a dual-printer (i.e. dual-needle) step-by-step printing strategy is adopted. By utilizing the different permeability and flowability of the packaging material at different heating temperatures, the synergistic optimization of cavity depth filling and high-precision surface molding is achieved. CT tomography shows that the layer void filling rate reaches 99.2% (higher than 91.5% of the single-needle solution in embodiment 1), and the interface bonding strength test reaches 1.8 MPa (50% higher than the single-needle solution in embodiment 1).

[0218] Example 5

[0219] The difference between Example 4 and Example 5 is that the encapsulation material for the battery cell in Example 5 is ethylene-vinyl acetate copolymer (EVA). All other steps and parameters are the same as in Example 4.

[0220] In the battery cell packaging method of this embodiment 5, a dual-printer (i.e. dual-needle) step-by-step printing strategy is adopted. By utilizing the different permeability and flowability of the packaging material at different heating temperatures, the synergistic optimization of cavity depth filling and high-precision surface forming is achieved.

[0221] Comparative Example 1

[0222] Unlike Example 1, after the wafer stacking is completed, the printing, packaging, and thermoforming processes of the wafer stack structure in Example 1 are not performed. Instead, the wafer stack structure is directly transferred to subsequent assembly processes such as isostatic pressing. All other steps and parameters are the same as in Example 1.

[0223] Comparative Example 2

[0224] Unlike Example 2, after the wafer stacking is completed, the printing, packaging, and thermoforming processes of the wafer stack structure in Example 1 are not performed. Instead, the wafer stack structure is directly transferred to subsequent assembly processes such as isostatic pressing. All other steps and parameters are the same as in Example 2.

[0225] Comparative Example 3

[0226] Unlike Example 3, after the wafer stacking is completed, the printing, packaging, and thermoforming processes of the wafer stack structure in Example 1 are not performed. Instead, the wafer stack structure is directly transferred to subsequent isostatic pressing processes. All other steps and parameters are the same as in Example 3.

[0227] Comparative Example 4

[0228] Unlike Example 1, after the wafer stacking is completed, the hot pressing process of Example 1 is not performed. Instead, the wafer structure with encapsulation material obtained by printing and packaging is directly cooled and solidified, and then transferred to subsequent assembly processes such as isostatic pressing. The remaining steps and parameters are the same as in Example 1.

[0229] Comparative Example 5

[0230] Unlike Example 1, in the printing and encapsulation step, the hot-melt resin material used is ethylene-vinyl acetate copolymer (EVA), and the printing temperature is set to 70 °C. All other steps and parameters are the same as in Example 1.

[0231] In this Comparative Example 5, ethylene-vinyl acetate copolymer (EVA) was used directly as the encapsulation material without any compounding. Figure 10a This is a cross-sectional scanning electron microscope image of the battery cell in Comparative Example 5. Figure 10b This is an EDS elemental analysis photograph of a cross-section of the battery cell in Comparative Example 5. (By...) Figure 10a and Figure 10b It is evident that the encapsulation structure formed by EVA packaging has a continuous, straight boundary with the stacked layers (active material layer). There is almost no element diffusion at the interface, resulting only in a mechanically stacked contact. The measured interfacial bonding strength is only 0.5 MPa. This weak bonding mode and interfacial bonding force are likely insufficient to withstand the volumetric deformation stress of the battery during isostatic pressing or charge / discharge processes, leading to a situation similar to... Figure 11a and Figure 11b Problems such as deformation and detachment of the packaging structure.

[0232] Solid-state batteries were obtained by assembling the cells of Examples 1 to 5 and Comparative Examples 1 to 5, and charge-discharge tests were conducted. The charge-discharge range was 2.1 to 4.3 V, and the test temperature was 30 °C. The test results are shown in Table 1 (0.1C cycle). The obtained charge-discharge test performance data are shown in Table 1.

[0233] Table 1

[0234]

[0235] The results of the above embodiments and comparative examples show that solid-state batteries with encapsulation structures can effectively avoid short circuits during pressurized assembly and pressurized operation. The cell yields of Embodiment 1 and Embodiment 2 with encapsulation structures are relatively high, while the cell manufacturing yields of Comparative Examples 1 and 2 are extremely low. Figure 12 The charging and discharging curves of the battery cells in Example 1 and Comparative Example 1 are shown. Figure 13 The cycling performance of the un-short-circuited cells in Example 1 and Comparative Example 1 shows that even if no short circuit is found during manufacturing, the cell performance is poor and the survival rate after cycling is low. This indicates that some cells will still short-circuit due to edge stress during cycling, and the capacity performance in subsequent charge and discharge cycles is also poor, which is also due to micro-short circuits occurring inside the battery.

[0236] Taking Example 1 as an example, the present invention improves the cell yield (from 34% in Comparative Example 1 to 75%) through the 3D printing packaging method, and directly reduces the average manufacturing cost per cell by 41%. Based on a 1 GWh solid-state battery production line per year (nominal capacity of 205 Wh per cell, equivalent to a production volume of 4,878,049 cells), and assuming an average cell price of 80 yuan per cell, the 41% yield improvement corresponds to a reduction in annual manufacturing costs of over 600 million yuan. From a performance perspective, the 94% cycle life after 100 cycles, compared to 64% in Comparative Example 1, results in a 35%–40% reduction in maintenance costs due to extended battery life.

[0237] Both Example 3 and Comparative Example 3 used defective electrode sheets for cell assembly. The cells in Comparative Example 3 were almost entirely ineffective, while the cells processed in Example 3 could improve the yield of these defective cells to 22%. That is, the present invention solves the problem of some electrode edge defects by insulating and encapsulating the edges. In actual production, this will inevitably play an important role in improving the overall yield of electrode sheets and the yield of cells.

[0238] Compared to Example 1, Comparative Example 4 lacked the secondary curing hot-pressing step. One purpose of this step is to enhance the filling of cavities by the hot-melt material, preventing incomplete filling of some cavities. Secondly, it strengthens the edge contact between the insulation structure and the original bare semi-finished cell. Hot pressing and vibration enhance resin penetration on the cell's sides, thereby improving the connection strength. Thirdly, it simultaneously improves the contact of other solid-solid interfaces within the cell, repairing some defects such as poor contact or surface cracks through high-frequency micro-vibration. Experimental results show that while the absence of the secondary curing hot-pressing step provides good short-circuit protection in the initial cell manufacturing stage, resulting in a relatively high initial cell yield, as cycling progresses, stresses such as volume changes in the solid cell may cause the insulation structure to detach, thus losing edge short-circuit protection and reducing the cell's post-cycle survival rate. Electrical performance data indicates that high-frequency micro-vibration can slightly improve the cell's capacity and other performance characteristics.

[0239] Through the detailed description of the embodiments of the present invention above, it is clear that the solid-state cell edge short-circuit protection encapsulation method provided in this application effectively and precisely solves the key problem of edge short circuits caused by overhang design in solid-state batteries at the design level. While solving the core problem, this method also fully considers various defects that may remain in the preceding processes such as electrode manufacturing and stacking, such as edge defects of the electrode, burrs generated at the edge of the foil, and misalignment during the stacking process. These defects are effectively compensated for through a reasonable and efficient encapsulation design. At the same time, the hot-melt material provided in this embodiment has excellent high permeability, enabling it to quickly and fully penetrate into every minute part of the cell edge, tightly bonding with the cell structure. Utilizing the elastic properties of the resin material, it effectively alleviates the stress generated inside the battery during actual operation, greatly reducing the risk of battery performance degradation or damage caused by stress. Practical verification shows that this method significantly improves the yield of cell manufacturing and also demonstrates excellent performance in cell performance, further enhancing the stability, safety, and service life of the cell. In summary, the embodiments proposed in this invention have achieved excellent technical results in many aspects, such as solving the key problem of overhang short circuit, making up for defects in previous processes, relieving operational stress, and improving manufacturing yield and cell performance.

[0240] In this embodiment of the disclosure, the method for determining the yield of the battery cell is: open circuit voltage matching design value ±0.05V, and DC internal resistance difference of the same type of battery cell ≤5%.

[0241] In this embodiment, differential scanning calorimetry (DSC) is used to measure the melting point of the hot-melt resin material, a melt indexer is used to measure the melt index, and a rotational viscometer is used to measure the viscosity of the material at 180°C, which is taken as the melt viscosity of the material. The contact angle is measured using a high-temperature contact angle meter at 90°C.

[0242] The battery cells in Embodiments 1 to 5 of this disclosure are designed to have a capacity of 5Ah for pouch cells.

[0243] In this embodiment of the disclosure, the steps of assembling the battery cells into a solid-state battery include: isostatic pressing, tab welding, and final packaging. The isostatic pressing parameters in the assembly process are 500 MPa and 15 min; the remaining assembly processes can be performed using conventional methods.

[0244] The foregoing description and accompanying drawings fully illustrate embodiments of this disclosure to enable those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, procedural, and other changes. The embodiments represent only possible variations. Individual components and functions are optional unless explicitly required, and the order of operation may vary. Parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terminology used in this application is for describing embodiments only and is not intended to limit the claims. As used in the description of embodiments and claims, the singular forms “a,” “an,” and “the” are intended to equally include the plural forms unless the context clearly indicates otherwise. Similarly, the term “and / or” as used in this application means including one or more of the associated listed items and all possible combinations thereof. Additionally, when used in this application, the term "comprise" and its variations "comprises" and / or "comprising" refer to the presence of stated features, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or groups thereof. Without further limitations, an element defined by the phrase "comprises a..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element. In this document, each embodiment may focus on the differences from other embodiments, and similar or identical parts between embodiments can be referred to mutually. For methods, products, etc., disclosed in the embodiments, if they correspond to the method section disclosed in the embodiments, the relevant parts can be referred to the description of the method section.

[0245] Those skilled in the art will recognize that the units and steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0246] 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 this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. In some alternative implementations, the functions marked in the blocks may occur in a different order than that shown in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in 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 actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. Each block in a block diagram and / or flowchart, and combinations of blocks in a block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.

Claims

1. A method for packaging a battery cell, characterized in that, include: A stacked structure is obtained by stacking the positive electrode sheet, the negative electrode sheet, and the solid electrolyte layer in the order of positive electrode sheet, negative electrode sheet, and solid electrolyte layer; wherein, the periphery of the stacked structure has lamellar gaps. An encapsulation material is placed into the gaps between the layers of a laminated structure using 3D printing or infusion methods to obtain an encapsulated laminated structure. The encapsulation material can penetrate into the interior of the layers surrounding the gaps, forming a permeable portion. The encapsulation material includes a hot-melt resin material, comprising, by weight: 40-80 parts of a base resin, 5-10 parts of a compatibilizer, 1-3 parts of a coupling agent, and 0-60 parts of an inorganic filler. The base resin includes a polymer containing one or more polar functional groups selected from ester, carboxyl, anhydride, amide, amino, hydroxyl, and epoxy groups. The compatibilizer and coupling agent include polymers containing one or more polar functional groups selected from ester, carboxyl, anhydride, amide, amino, hydroxyl, and epoxy groups. The hot-melt resin material has the following characteristics: melting point of 60-100℃; melt index of 200-400 g / 10 min; and melt viscosity of 2000-12000 g / min at a measurement temperature of 180℃. mPa·s; at a measurement temperature of 90℃, the contact angle with the battery electrode surface is ≤60°; wherein, an encapsulation material is placed into the gaps between the layers of the stacked structure using a 3D printing method or a potting method to obtain an encapsulated stacked structure; including: placing a first permeable encapsulation material into the gaps between the layers of the stacked structure using a 3D printing method or a potting method to obtain a first stacked structure with a first encapsulation layer; wherein, the first encapsulation layer has a permeable portion that penetrates into the layers surrounding the gaps between the layers and a first filling portion located in the gaps between the layers, the thickness of the first filling portion being less than the depth of the gaps between the layers; placing a second permeable encapsulation material into the gaps between the layers of the first stacked structure, and in the first... A second encapsulation layer is obtained outside the first encapsulation layer to obtain an encapsulated stack structure; wherein, the outer surface of the second encapsulation layer is flush with the peripheral side surface of the stack structure, or, the second encapsulation layer protrudes from the peripheral side surface of the stack structure and forms a covering portion that encapsulates the peripheral side surface of the stack structure; and the permeability of the second permeable encapsulation material is less than the permeability of the first permeable encapsulation material; wherein, the first permeable encapsulation material is obtained by heating a hot-melt resin material to a first temperature, and the second permeable encapsulation material is obtained by heating a hot-melt resin material to a second temperature, wherein the first temperature is greater than the second temperature; wherein, the first temperature and the second temperature are selected from temperature values ​​within the melting point range of the hot-melt resin material. The encapsulation stack structure is placed on a heating plate at a first preset temperature, and pressure and vibration are applied for a second preset time; then cooled to obtain a battery cell with an encapsulation structure; wherein, a heating groove is provided on the heating plate, the groove body of the heating groove is consistent with the outer contour of the battery cell with the encapsulation structure, the encapsulation stack structure is placed in the heating groove, and the first preset temperature can soften the hot melt resin material again to give it a certain fluidity. In the battery cell with a packaging structure, the packaging structure includes a filling part and a permeation part. The filling part is disposed in the gap between the layers of the stacked structure, and the permeation part is the part of the filling part that extends and permeates into the interior of the layers around the gap between the layers. The penetration depth of the permeation part is greater than or equal to 1 μm and less than or equal to 300 μm. The interior of the layers refers to the interior of the positive electrode active material layer, the interior of the negative electrode active material layer, and the interior of the solid electrolyte layer.

2. The packaging method according to claim 1, characterized in that, The first temperature is selected from a first sub-temperature range near the high-temperature end within the melting point range of the hot-melt resin material, and the second temperature is selected from a second sub-temperature range near the low-temperature end within the melting point range of the hot-melt resin material.

3. The packaging method according to claim 2, characterized in that, The first sub-temperature range is 80–100 ℃; the second sub-temperature range is 60–85 ℃.

4. The packaging method according to claim 1, characterized in that, The first preset temperature is greater than or equal to T. min And less than or equal to T′, T′=T min +δ×(T max -T min ), where T max T represents the upper limit of the melting point range of hot-melt resin materials. min δ represents the lower limit of the melting point range of hot-melt resin materials, and its value range is [0, 1 / 3].

5. The packaging method according to claim 4, characterized in that, The first preset temperature is 60℃~70℃.

6. The packaging method according to claim 5, characterized in that, The first preset temperature is 60℃.

7. The packaging method according to claim 1, characterized in that, The second preset time is 30 seconds.

8. The packaging method according to claim 1, characterized in that, A multi-head 3D printing device or a multi-head dispensing machine is used to apply encapsulation material into the gap area of ​​the stacked structure; wherein, the first dispensing head is used to output the first permeable encapsulation material, and the second dispensing head is used to output the second permeable encapsulation material.

9. The packaging method according to any one of claims 1 to 8, characterized in that, The encapsulation material is placed into the gaps between the layers of the laminated structure using 3D printing or infusion methods, including: placing the encapsulation material into the gaps between the layers of the laminated structure layer by layer, with the heating temperature of the encapsulation material decreasing from the inner layer to the outer layer.

10. The packaging method according to any one of claims 1 to 8, characterized in that, In addition to "using 3D printing or infusion methods to place encapsulation material into the gaps between the layers of a laminated structure," it also includes: Obtain penetration information that reflects the penetration status of the encapsulation material; Adjust the permeability of the encapsulation material based on permeation information.

11. The packaging method according to claim 10, characterized in that, Infiltration information that reflects the infiltration of the first permeable encapsulating material includes: infrared imaging image information.

12. The packaging method according to any one of claims 1 to 8, characterized in that, Methods of applying pressure include applying constant pressure.

13. The packaging method according to claim 12, characterized in that, The pressure includes a constant pressure of 0.3 to 0.5 MPa.

14. The packaging method according to any one of claims 1 to 8, characterized in that, One way to apply pressure is by applying gradient pressure.

15. The packaging method according to claim 14, characterized in that, The pressure includes a gradient pressure in the range of 0.3 to 3 MPa.

16. The packaging method according to any one of claims 1 to 8, characterized in that, Vibrations include those with a frequency of 10–50 Hz and an amplitude of less than or equal to 50 μm.

17. The packaging method according to any one of claims 1 to 8, characterized in that, The vibrations include gradient step vibrations in the frequency range of 20 Hz to 2000 Hz.

18. The packaging method according to any one of claims 1 to 8, characterized in that, A 3D printing temperature-controlled encapsulation method is obtained by placing encapsulation material into the gaps between the layers of a stacked structure using 3D printing, including: A stacked structure is obtained by stacking the positive electrode sheet, the negative electrode sheet, and the solid electrolyte layer in the order of positive electrode sheet, negative electrode sheet, and solid electrolyte layer; wherein, the periphery of the stacked structure has lamellar gaps. The stacked structure is vertically positioned in the printing area of ​​the 3D printing equipment with the side to be printed facing upwards. Obtain the outline entity data of the side of the stacked structure to be printed; obtain the outline 3D model based on the outline entity data; slice the outline 3D model, perform path planning and printing parameter design, and obtain printing information; The 3D printing equipment prints the encapsulation material onto the side to be printed based on the printing information and the heating temperature of the encapsulation material, thus completing the encapsulation printing of the side to be printed of the stacked structure and obtaining the stacked structure with the encapsulation material.

19. The packaging method according to any one of claims 1 to 8, characterized in that, In hot-melt resin materials, The matrix resin includes one or more mixtures of ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, polyethylene terephthalate, and ethylene-acrylic acid copolymer; and / or Compatibilizers include one or more of maleic anhydride-grafted polyolefins, epoxy-modified polyolefins, and polypropylene-grafted polystyrene; and / or Coupling agents include silane coupling agents; and / or Coupling agents include titanate coupling agents; and / or Inorganic fillers include one or more of the following: barium sulfate, titanium dioxide, talc, bentonite, quartz sand, alumina, calcium carbonate, glass powder, and zinc oxide.

20. The packaging method according to claim 19, characterized in that, In hot-melt resin materials, In cases where the coupling agent includes a silane coupling agent, the coupling agent includes one or more of γ-aminopropyltriethoxysilane, vinyltrimethoxysilane, and vinyltriethoxysilane; In cases where the coupling agent includes a titanate coupling agent, the coupling agent includes isopropyl triisostearate titanate and / or isopropyl dioleoyloxy titanate.

21. The packaging method according to any one of claims 1 to 8, characterized in that, In hot-melt resin materials, Inorganic fillers include alumina nanoparticles with a particle size of 20–50 nm.

22. A battery cell, characterized in that, Obtained by the packaging method of the battery cell as described in any one of claims 1 to 21; the battery cell comprises: The laminated structure includes alternating negative and positive electrode sheets, with a solid electrolyte layer disposed between adjacent positive and negative electrode sheets; the periphery of the laminated structure forms lamellar gaps. The encapsulation structure includes a filling portion and a permeation portion. The filling portion is disposed in the gaps between the layers of the stacked structure, and the permeation portion is the part of the filling portion that extends into the interior of the layers surrounding the gaps between the layers. The permeation depth of the permeation portion is greater than or equal to 1 μm and less than or equal to 300 μm. The interior of the sheet refers to the interior of the positive electrode active material layer, the interior of the negative electrode active material layer, and the interior of the solid electrolyte layer.

23. The battery cell according to claim 22, characterized in that, The penetration depth of the permeable portion is greater than or equal to 10 μm and less than or equal to 300 μm; and / or The percentage of the electrode sheet area occupied by the permeable portion is less than or equal to 1%.

24. The battery cell according to claim 23, characterized in that, The penetration depth of the permeable part is greater than or equal to 50 μm and less than or equal to 300 μm.

25. The battery cell according to claim 23, characterized in that, The penetration depth of the permeable part is greater than or equal to 100 μm and less than or equal to 300 μm.

26. The battery cell according to claim 23, characterized in that, The penetration depth of the permeable part is greater than or equal to 150 μm and less than or equal to 300 μm.

27. The battery cell according to claim 23, characterized in that, The penetration depth of the permeable part is greater than or equal to 200 μm and less than or equal to 250 μm.

28. The battery cell according to any one of claims 22 to 27, characterized in that, The lamination voids include misalignment voids caused by the misalignment of the negative electrode, solid electrolyte layer, and positive electrode during stacking, and / or overhang voids corresponding to the overhang region formed by the negative electrode extending beyond the positive electrode on at least one side in the circumferential direction; and / or The packaging structure also includes a covering portion, which is connected to the filling portion and covers the peripheral side of the stacked structure.

29. A battery cell packaging system for implementing the battery cell packaging method according to any one of claims 1 to 21, characterized in that, include: 3D printing equipment; The conveying and positioning module is used to flip the completed stacked structure vertically and then convey it to the working area of ​​the 3D printing equipment. The scanning module is used to scan the outline solid data of the side of the stacked structure to be printed, which is set in the working area of ​​the 3D printing equipment. The control unit obtains a 3D contour model based on the contour entity data; it slices the 3D contour model, performs path planning and coating parameter design, and obtains coating information; the 3D printing equipment receives the coating information from the control unit and, based on the coating information, places molten encapsulation material heated to a preset temperature on the side of the stacked structure to be printed in the working area, so that the encapsulation material can penetrate into the interior of the layers around the gaps in the layers to form a penetration part. and The hot pressing device includes a heating plate, a pressure plate, and a vibration structure. The heating plate is provided with a heating groove, the cavity of which is consistent with the outer contour of the stacked structure on which the encapsulation material is placed. The pressure plate is movably disposed above the heating plate and can be fastened to the heating plate to pressurize the stacked structure placed in the heating groove. The vibration structure is used to apply vibration to the stacked structure disposed on the heating plate.

30. The battery cell packaging system according to claim 29, characterized in that, The vibration structure includes a flexible vibrating disc, which is set in the heating groove of the heating plate, or the heating plate is set on the flexible vibrating disc.

31. The battery cell packaging system according to claim 29, characterized in that, Also includes: Infrared scanning equipment is used to perform infrared imaging scanning and monitoring of the gaps between the layers while placing encapsulation material into the gaps of the laminated structure, so as to obtain infrared imaging image information that can reflect the permeation information of the encapsulation material.

32. The battery cell packaging system according to claim 29, characterized in that, The coating information obtained by the control unit includes the printing path and printing information; the printing information includes one or more of the following: loop trajectory and / or straight trajectory; line width of 80-120 μm; layer height of 5-20 μm; printing speed of 25-45 mm / s; The heating temperature is within the melting point range of the encapsulation material; the printhead temperature is 1 to 50°C higher than the heating temperature.

33. The battery cell packaging system according to claim 32, characterized in that, The heating temperature in the printed information includes a first heating temperature and a second heating temperature, with the first heating temperature being greater than the second heating temperature; the first heating temperature is the heating temperature of the first permeable encapsulating material, and the second heating temperature is the heating temperature of the second permeable encapsulating material.

34. The battery cell packaging system according to claim 33, characterized in that, The first heating temperature is selected from 80℃ to 100℃, and the second heating temperature is selected from 60℃ to 100℃.

35. A solid-state battery, characterized in that, include: A battery cell packaged using the battery cell packaging method as described in any one of claims 1 to 21; Alternatively, the battery cell as described in any one of claims 22 to 28; or, the battery cell obtained by packaging using the battery cell packaging system as described in any one of claims 29 to 34.

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