Battery cell, packaging method and packaging system thereof, solid-state battery and hot-melt resin material

Abstract

The invention relates to the technical field of solid-state batteries, and discloses a battery cell which comprises a lamination structure and a packaging structure, the lamination structure comprises negative pole pieces and positive pole pieces which are alternately laminated, and a solid-state electrolyte layer is arranged between the adjacent positive pole pieces and negative pole pieces; lamellar gaps are formed in the peripheral side surface of the laminated structure; the packaging structure comprises a filling part and a permeation part, the filling part is arranged in the gap of the sheet layer, and the permeation part extends and permeates into the sheet layer from the filling part. The arrangement of the permeation part ensures the interface bonding effect of the packaging structure and the sheet layer of the lamination structure, the bonding strength is improved, and the permeation part permeates into the active material area of the electrode pole piece to improve the cohesion and has certain deformation capacity so as to adapt to the forming pressure of the lamination cell and the volume change of the active material; and new edge stress generation caused by contact separation and excessive deformation of the packaging structure and the sheet layer is avoided, so that the performance of the solid-state battery is improved. The invention 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 technical field of solid-state batteries, for example, to an electric core, its packaging method, packaging system, solid-state battery, and a hot-melt resin material. Background Art

[0002] The ultimate goals pursued by power batteries are extremely high energy density, high rate performance, high safety, long life, wide temperature range, and low cost. With the rapid development of new energy vehicles, traditional lithium-ion batteries using liquid electrolytes can no longer meet the market's requirements for battery performance, and there is an urgent need to develop the next-generation battery technology. The solid electrolytes used in solid-state batteries have high mechanical strength, and the amount of electrolyte used and interfacial side reactions are much less than those of liquid batteries. Therefore, solid-state batteries have significant advantages in terms of energy density, safety, life, and climate adaptability. Due to the solid-solid contact between components, the interfacial impedance is large, and solid-state batteries need to be densified under pressure during manufacturing. The traditional winding process is difficult to be compatible with the huge forming pressure. Therefore, the lamination process based on roll pressing or isostatic pressing has become the current preferred choice for solid-state batteries.

[0003] In the lamination process of solid-state batteries, the positive and negative electrode plates of equal size will be misaligned due to the insufficient accuracy of the lamination equipment. The misalignment of the electrode plates easily leads to lithium plating at the edge of the negative electrode during the charge and discharge process, bringing a short-circuit risk. To solve this problem, usually, the area of the negative electrode plate is designed to be slightly larger than that of the positive electrode plate, so that the negative electrode can completely cover the positive electrode (i.e., overhang design). However, due to the unequal size of the positive and negative electrode plates, when a large forming pressure (such as isostatic pressing or roll pressing) is applied, it is easy to induce stress concentration in the remaining part at the edge of the electrode plate, resulting in the fracture of the edge of the electrolyte film under the action of shear force, and then leading to the contact between the edges of the positive and negative electrode plates and causing an internal short circuit, reducing the manufacturing yield of the battery, especially when manufacturing multi-layer solid-state electric cores, the yield decline is more significant. Regarding the yield problem of overhang lamination and isostatic pressing process of solid-state batteries, those skilled in the art have conducted corresponding research on short-circuit prevention solid-state batteries.

[0004] Currently, for the problem that the overhang area of the negative electrode is prone to collapse during the assembly process of solid-state batteries, resulting in the contact between the positive and negative electrodes and then causing battery short circuit, most of them use filling substances in the voids corresponding to the overhang area of the negative electrode for packaging support to avoid the collapse of the overhang area of the negative electrode during the assembly process of solid-state batteries. However, in the actual R & D process, it is found that in the isostatic pressing process of the laminated electric core of the existing packaging support structure in the overhang area, the electrode plate / electrolyte layer will be deformed by force, and the size will shrink significantly, resulting in inconsistent deformation / shrinkage amplitude between the electrode plate and the packaging support structure, local debonding of the packaging support structure, and even causing the entire piece to fall off from the edge of the electrode plate, resulting in the ineffective improvement of the electric core yield and even affecting the improvement of subsequent battery performance.

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

[0006] To provide a basic understanding of some aspects of the disclosed embodiments, a simple summary is given below. This summary is not an extensive review nor is it intended to identify key / important elements or delineate the scope of protection of these embodiments, but rather serves as a prelude to the detailed description that follows.

[0007] Embodiments of the present disclosure provide an electrode cell, a packaging method thereof, a packaging system, a solid-state battery, and a hot-melt resin material, to solve the problem that the laminated void packaging structure of the existing laminated electrode cell is prone to debonding, and even prone to falling off entirely from the edge of the electrode sheet, affecting the battery yield and subsequent battery performance.

[0008] In some embodiments, the electrode cell includes: a laminated structure including alternately laminated negative electrode sheets and positive electrode sheets, and a solid electrolyte layer is disposed between adjacent positive electrode sheets and negative electrode sheets; a laminated void is formed on the circumferential side surface of the laminated structure; a packaging structure including a filling portion and a penetration portion, the filling portion is disposed in the laminated void of the laminated structure, and the penetration portion is a part that extends from the filling portion and penetrates into the interior of the sheet layer around the laminated void; the penetration depth of the penetration portion is greater than or equal to 1 μm.

[0009] In some embodiments, the packaging method of the electrode cell includes: stacking the positive electrode sheet, the negative electrode sheet, and the solid electrolyte layer in the order of the positive electrode sheet, the solid electrolyte layer, the negative electrode sheet, and the solid electrolyte layer to obtain a laminated structure; wherein, a laminated void is formed on the circumferential side surface of the laminated structure; a packaging material is disposed in the laminated void of the laminated structure to obtain an electrode cell with a packaging structure; wherein, the packaging material can penetrate into the interior of the sheet layer around the laminated void to form a penetration portion.

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

[0011] In some embodiments, the encapsulation system of the battery cell includes: a fluid material precision coating device; a transfer and positioning module configured to flip the stacked structure after stacking to a vertical position and then transfer it to the working area of the fluid material precision coating device; a scanning module configured to scan the contour entity data of the side to be printed of the stacked structure disposed in the working area of the fluid material precision coating device; a control unit configured to obtain a three-dimensional contour model based on the contour entity data, perform slicing processing on the three-dimensional contour model, conduct path planning and coating parameter design to obtain coating information; and the fluid material precision coating device receives the coating information from the control unit and sets the molten encapsulation material heated to a preset temperature on the side to be printed of the stacked structure located in the working area according to the coating information.

[0012] In some embodiments, the hot-melt resin material is used as the encapsulation material for the encapsulation structure of the battery cell described above, or as the encapsulation material in the encapsulation method of the battery cell described above; or as the encapsulation material used in the 3D printing device of the encapsulation system of the battery cell described above. By mass, the hot-melt resin material includes: 40 - 80 parts of a matrix resin, 5 - 10 parts of a compatibilizer, 0 - 3 parts of a coupling agent, and 0 - 60 parts of an inorganic filler; wherein, the matrix resin includes a polymer containing one or more polar functional groups among an ester group, a carboxyl group, an acid anhydride group, an amide group, an amino group, a hydroxyl group, and an epoxy group.

[0013] In some embodiments, the solid-state battery includes: the battery cell described above; or a battery cell encapsulated by using the encapsulation method of the battery cell described above; or a battery cell encapsulated by using the encapsulation system of the battery cell described above.

[0014] The battery cell, its encapsulation method, encapsulation system, solid-state battery, and hot-melt resin material provided by the embodiments of the present disclosure can achieve the following technical effects: In the battery cell of the embodiment of the present disclosure, the encapsulation structure includes, in addition to the filling part disposed in the voids between the layers of the stacked structure, a penetration part that penetrates into the layers around the voids between the layers. The provision of the penetration part 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 penetration part penetrates into the active material area of the electrode tab to enhance the cohesive force and has a certain deformation ability to adapt to the forming pressure of the stacked battery cell and the volume change of the active material (including the volume change caused by the forming pressure and charge and discharge), so as to avoid the encapsulation structure being separated from the layers (electrode tab and / or solid electrolyte layer), especially in the isostatic pressing process of a solid-state battery, the layers are deformed too much, resulting in the separation of the encapsulation structure from the layers and the formation of new edge stresses. That is, the battery cell of the embodiment of the present disclosure breaks through the technical limitations of the existing encapsulation structure for voids between layers. By design, the encapsulation material penetrates into the electrode material area. Although there will be a very small energy loss in theoretical calculation (generally controlled within 1%), the bonding strength between the encapsulation structure and the stacked structure is improved and separation will not occur, especially after the isostatic pressing process of a solid-state battery. The yield of the battery is improved, and at the same time, the utilization rate of the electrode active material can be increased, and the performance of the solid-state battery can be enhanced.

[0015] The battery cell encapsulation method of the embodiment of the present disclosure is more practical. It can use continuously coated electrode tabs, be compatible with the overhang design and size equalization design of the positive electrode tab and the negative electrode tab, and can simplify the edge short-circuit prevention treatment of a single electrode tab into the edge short-circuit prevention encapsulation of the stacked structure, greatly reducing the difficulty, cycle and cost of the battery manufacturing process.

[0016] The above general description and the following description are only exemplary and explanatory, and are not used to limit the present application. Description of the Drawings

[0017] One or more embodiments are exemplarily illustrated by corresponding drawings. These exemplary illustrations and the drawings do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are shown as similar elements. The drawings do not constitute a proportional limitation, and among them: Figure 1 is a schematic structural diagram of a battery cell provided by an embodiment of the present disclosure; Figure 2 is a partially enlarged schematic structural diagram of another battery cell provided by an embodiment of the present disclosure; Figure 3 is a schematic structural diagram of another battery cell provided by an embodiment of the present disclosure; Figure 4 is a schematic structural diagram of another battery cell provided by an embodiment of the present disclosure; Figure 5 is a schematic flow diagram of a battery cell encapsulation method provided by an embodiment of the present disclosure; Figure 6 It is a schematic flowchart of another method for encapsulating an electric core provided by an embodiment of the present disclosure; Figure 7 It is a schematic structural diagram of a hot pressing device provided by an embodiment of the present disclosure; Figure 8 It is a schematic structural diagram of an electric core encapsulation system provided by an embodiment of the present disclosure; Figure 9a It is a cross-sectional scanning electron microscope photograph of the electric core of Embodiment 1 of the present disclosure; Figure 9b It is an EDS element analysis photograph of the cross-section of the electric core of Embodiment 1 of the present disclosure; Figure 10a It is a cross-sectional scanning electron microscope photograph of the electric core of Comparative Example 5 of the present disclosure; Figure 10b It is an EDS element analysis photograph of the cross-section of the electric core of Comparative Example 5 of the present disclosure; Figure 11a and Figure 11b It is a schematic structural diagram of the deformation or detachment of the encapsulation structure of the electric core of Comparative Example 5 of the present disclosure; Figure 12 It is a charge and discharge curve graph of the electric cores of Embodiment 1 and Comparative Example 1 of the present disclosure; Figure 13 It is a cycle performance graph of the non-shorted electric cores of Embodiment 1 and Comparative Example 1 of the present disclosure.

[0018] Reference numerals: 10. Laminated structure; 11. Negative electrode tab; 111. Negative electrode active material layer; 112. Negative electrode current collector layer; 1121. Burr; 1122. Edge defect of the tab; 12. Solid electrolyte layer; 13. Positive electrode tab; 131. Positive electrode active material layer; 132. Positive electrode current collector layer; 1301. Dislocation protrusion; 1302. Dislocation depression; 20. Encapsulation structure; 21. Filling part; 210. Penetration part; 22. Coating part; 30. Hot pressing device; 31. Heating plate; 310. Heating groove; 311. Vibration structure; 32. Pressing plate; 41. Precision fluid material coating equipment; 42. Scanning module; 43. Control unit. Detailed implementation manners

[0019] In order to understand the features and technical content of the embodiments of the present disclosure in more detail, the implementation of the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The accompanying drawings are only for reference and explanation, and are not used to limit the embodiments of the present disclosure. In the following technical description, for the sake of explanation, numerous details are provided to give a thorough understanding of the disclosed embodiments. However, one or more embodiments may still be implemented without these details. In other cases, well-known structures and devices may be shown in a simplified manner to simplify the drawings.

[0020] In the description of the embodiments of the present disclosure, the terms "first", "second", etc. in the specification, claims and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that such terms may be interchanged when appropriate, so as to understand the embodiments of the present disclosure described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion.

[0021] In the embodiments of the present disclosure, the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "middle", "outer", "front", "rear", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe the embodiments of the present disclosure and their embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation. And, in addition to being able to represent an orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0022] In addition, the terms "arranged", "connected", "fixed" should be understood in a broad sense. For example, "connected" may be a fixed connection, a detachable connection, or an integral structure; it may be a mechanical connection or an electrical connection; it may be directly connected, or indirectly connected through an intermediate medium, or there may be internal communication between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present disclosure can be understood according to specific circumstances.

[0023] Unless otherwise specified, the term "plurality" means two or more.

[0024] In the embodiments of the present disclosure, the character " / " indicates that the objects before and after are in an "or" relationship. For example, A / B means: A or B.

[0025] The term "and / or" is an associative relationship describing objects, indicating that three relationships may exist. For example, A and / or B means: A or B, or, A and B these three relationships.

[0026] It should be noted that, without conflict, the embodiments in the present disclosure and the features in the embodiments may be combined with each other.

[0027] Combined Figures 1 to 4 As shown, the embodiments of the present disclosure provide a battery cell, including a laminated structure 10 and a packaging structure 20. The laminated structure 10 includes alternately stacked negative electrode sheets 11 and positive electrode sheets 13, and a solid electrolyte layer 12 is disposed between adjacent positive electrode sheets 13 and negative electrode sheets 11; a sheet layer gap is formed on the circumferential side surface of the laminated structure 10. The packaging structure 20 includes a filling portion 21 and a penetration portion 210. The filling portion 21 is disposed in the sheet layer gap of the laminated structure 10, and the penetration portion 210 is a part that extends from the filling portion 21 and penetrates into the interior of the sheet layer around the sheet layer gap; the penetration depth of the penetration portion 210 is greater than or equal to 1 μm.

[0028] In the battery cell of the embodiments of the present disclosure, in addition to the filling portion 21 disposed in the sheet layer gap of the laminated structure 10, the packaging structure further includes a penetration portion 210 that penetrates into the interior of the sheet layer around the sheet layer gap. The setting of the penetration portion 210 ensures the interfacial bonding effect between the packaging structure 20 and the sheet layer of the laminated structure 10, improves the bonding strength between the packaging structure and the sheet layer, and the penetration portion penetrates into the active material area of the electrode sheet to enhance the cohesive force and has a certain deformation ability to adapt to the forming pressure of the laminated battery cell and the volume change of the active material (including the volume change caused by the forming pressure and charge and discharge), avoiding the separation contact between the packaging structure and the sheet layer (electrode sheet and / or solid electrolyte layer) and excessive deformation resulting in the generation of new edge stresses, thereby improving the performance of the solid-state battery.

[0029] In the battery cell of the embodiments of the present disclosure, the bonding strength between the packaging structure and the sheet layer of the laminated structure reaches 1.2 MPa or more. The first-cycle discharge specific capacity of the solid-state battery assembled from the battery cell of the embodiments of the present disclosure can be improved.

[0030] In the battery cell of the embodiments of the present disclosure, "inside the sheet layer" refers to the inside of the positive electrode sheet, negative electrode sheet, and solid electrolyte layer, and more specifically, the positive active material layer, negative active material layer, and solid electrolyte layer.

[0031] In the battery cell of the embodiments of the present disclosure, the filling rate of the packaging structure 20 for the sheet layer gap 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%.

[0032] The battery cell in the embodiments of the present disclosure is a stacked battery cell and can be used as the battery cell of a solid-state battery. Optionally, the stacking structure 10 includes one or more stacking units, and each stacking unit includes a negative electrode tab 11, a solid electrolyte layer 12, and a positive electrode tab 13 stacked in sequence. When the stacking structure 10 includes multiple stacking units, the positive electrode tab 13 of one stacking unit and the negative electrode tab of an adjacent stacking unit are stacked through the solid electrolyte layer. That is, the stacking structure 10 is arranged and stacked in the manner of negative electrode tab 11 / solid electrolyte layer 12 / positive electrode tab 13 / solid electrolyte layer 12 / negative electrode tab 11 / solid electrolyte layer 12 / positive electrode tab 13 / .... Generally, the electrode tabs on the two surfaces of the stacking structure 10 are negative electrode tabs 11, but this is not limited thereto.

[0033] In the battery cell of the embodiments of the present disclosure, the sheet layer includes electrode tabs (positive electrode tabs and negative electrode tabs) and a solid electrolyte layer, and the sheet layer void is the void formed between the electrode tabs or between the electrode tab and the solid electrolyte layer. The sheet layer voids vary according to the size design of the electrode tabs. Optionally, the sheet layer voids include misalignment voids and / or overhang voids. The misalignment voids are generated due to misalignment when the negative electrode tab, the solid electrolyte layer, and the positive electrode tab are stacked. Generally, misalignment voids are generated when the positive electrode tab and the negative electrode tab of the same size design are misaligned during stacking (see Figure 3 shown). Among them, the same size design generally means that the areas of the active material regions are the same. The overhang void is the overhang void corresponding to the overhang region formed when at least one side of the circumferential direction of the negative electrode tab extends beyond the positive electrode tab (i.e., the overhang void). In this case, the negative electrode tab is designed to be larger than the positive electrode tab, so that at least one side of the circumferential direction of the negative electrode tab extends beyond the positive electrode tab to form an overhang region (see Figure 1 and Figure 4 shown). Relative to the circumferential outer contour of the stacking structure 10, the misalignment voids and / or overhang voids extend inwardly of the stacking structure 10 and have a certain depth (see the depth d1 shown in Figure 2 ). Under the forming pressure during the assembly of the solid-state battery, stress concentration is likely to occur, causing the problem of short circuit of the battery cell, thereby reducing the manufacturing yield and performance consistency of the battery cell. The encapsulation structure 20 fills these misalignment voids and / or overhang voids, thereby being able to solve the problem that these sheet layer voids are likely to cause stress concentration and result in short circuit of the battery cell under the forming pressure. At the same time, the encapsulation structure also has a penetration part 210 formed by penetrating into the sheet layer around the sheet layer voids. The setting of the penetration part 210 ensures the interfacial bonding effect between the encapsulation structure 20 and the sheet layer of the stacking structure 10 and improves the bonding strength between the encapsulation structure and the sheet layer.

[0034] In the battery cell of the embodiments of the present disclosure, the penetration part 210 of the encapsulation structure 20 penetrates into the sheets around the voids between the sheets of the stacked sheet structure 10. For example, the penetration part 210 penetrates into the active material of the positive electrode sheet, the solid electrolyte layer, and the active material of the negative electrode sheet around the voids between the sheets (see Figure 2 as shown). Therefore, theoretically, the encapsulating material penetrating into the sheets will cause the positive electrode sheet 13 to lose part of its theoretical capacity. However, in practical applications, the setting of the penetration part 210 can not only improve the bonding strength between the encapsulation structure and the stacked sheet structure, improve the yield of the battery cell, but also greatly improve the actual capacity of the battery cell, improve the first-cycle specific capacity and cycling performance of the battery, and thus improve the battery performance.

[0035] In some embodiments, the penetration depth d2 of the penetration part 210 is greater than or equal to 1 μm. By controlling the penetration depth, the loss of theoretical capacity and the improvement of the actual capacity are balanced to ensure that the battery performance can be improved. Optionally, the penetration depth of the penetration part is greater than or equal to 1 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part is greater than or equal to 10 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part is greater than or equal to 50 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part is greater than or equal to 100 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part is greater than or equal to 150 μm and less than or equal to 300 μm. Optionally, the penetration depth of the penetration part is greater than or equal to 200 μm and less than or equal to 250 μm. By controlling the penetration depth of the penetration part, the loss of theoretical capacity is controlled, and while ensuring the bonding strength to provide the yield of the battery cell, the battery performance can be better improved.

[0036] In some embodiments, the area percentage of the penetration part in the electrode sheet is less than or equal to 1%. That is, the penetration percentage of the penetration area of the penetration part in the area of the electrode sheet is less than or equal to 1%. In this embodiment, by controlling the penetration percentage of the penetration part, the loss of theoretical capacity and the improvement of the actual capacity are balanced to ensure that the battery performance can be improved. Optionally, the penetration percentage of the penetration area of the penetration part in the area of the electrode sheet is less than or equal to 0.8%. In this embodiment, the area (or penetration area) of the penetration part is calculated by taking the penetration depth of the penetration part as one of the multipliers. For example, taking the positive electrode sheet as an example, the penetration area of the penetration part is the product of the penetration depth of the penetration part and the peripheral length of the positive electrode sheet.

[0037] Optionally, the penetration depth d2 of the penetration part is less than or equal to 300 μm, and the penetration percentage of the penetration area of the penetration part in the area of the electrode sheet is less than or equal to 1%.

[0038] The battery cell of the embodiments of the present disclosure is more suitable for large-sized battery cells. It can be understood that the larger the size of the battery cell, the smaller the ratio of the penetration depth / penetration area of the penetration part to the area of the electrode tab, and thus the smaller the theoretical capacity loss. However, the bonding strength between the encapsulation structure and the laminated structure is not affected. While the yield of the battery cell is improved, the actual capacity of the battery cell can be greatly enhanced, the first-cycle specific capacity and the cycling performance of the battery can be improved, and thus the battery performance can be enhanced.

[0039] In some embodiments, as Figure 1 and Figure 4 shown, the encapsulation structure 20 further includes a covering part 22. The covering part 22 is connected to the filling part 21 and covers the peripheral side surface of the laminated structure 10. By wrapping the peripheral side end surface of the battery cell, defects left in the previous process sections such as defects at the edges of the tabs, burrs of the foil, and misalignment of the laminations are compensated. Moreover, with the fully enclosed outer frame encapsulation design, it not only protects the internal environment of the battery cell but also can accommodate the volume change during the operation of the battery cell, comprehensively improving the yield of battery cell manufacturing and the safety performance of the battery cell. For example, the covering part 22 can cover the burrs 1121 and the tab edge defects 1122 on the negative current collector layer 112 as shown in Figure 4 , as well as the misaligned protrusions 1301 and misaligned depressions 1302 generated when the laminations are misaligned. Burrs are extremely likely to pierce the electrolyte film, resulting in micro-short circuits due to the contact between the positive and negative electrodes, causing self-discharge of the battery and deterioration of the electrochemical performance. In terms of safety, the local current density at the micro-short circuit exceeds 100 A / cm 2 (far exceeding 1 - 5 A / cm 2 during normal charge and discharge), which will quickly accumulate heat and may trigger thermal runaway of the battery in severe cases.

[0040] In the battery cell of the embodiments of the present disclosure, the encapsulation structure 20 is obtained by setting the encapsulation material into the voids between the layers. The encapsulation material used for the encapsulation structure 20 can be the same material or different materials. For example, in the case where the encapsulation structure 20 includes a filling part 21, a penetration part 210, and a covering part 22, the filling part 21 and the penetration part 210 use the same material, and the covering part 22 uses a different material. It can be understood that the filling part 21 and the penetration part 210 need to be filled into the voids between the layers, and an encapsulation material with a certain permeability needs to be used to ensure that the encapsulation material can enter the voids between the layers and penetrate into the layers. While the covering part 22 covers the peripheral side surface of the laminated structure 10, a non-permeable encapsulation material can be used.

[0041] Optionally, the encapsulation material used for the encapsulation structure 20 is the same material. It can be completed by one encapsulation process, simplifying the encapsulation process.

[0042] 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.

[0043] In some embodiments, the encapsulation material of the encapsulation structure 20 includes a resin material whose permeability can vary with temperature. Generally, the higher the heating temperature of the resin material, the better its flowability and permeability. By controlling the heating temperature of the resin material, the flowability and permeability of the resin material can be adjusted. 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.

[0044] In some embodiments, the encapsulation material of the encapsulation structure 20 includes a hot-melt resin material.

[0045] 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 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. 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. The polymer containing the above specific polar functional groups can further improve the permeability of the encapsulation material, more effectively penetrate into the interior of the sheet layer, contact and penetrate with the substances inside the sheet layer (such as the active material and binder of the electrode sheet), and improve the bonding strength of the encapsulation structure.

[0046] Optionally, the encapsulation material of the encapsulation structure 20 includes a resin material whose permeability can vary with temperature and contains 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.

[0047] 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.

[0048] 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).

[0049] The above encapsulation materials such as insulating materials, resin materials, polymers, etc. can be used alone. When in use, they are heated and melted into a fluid to make them have a certain permeability. The molten encapsulation material is set in the sheet layer voids and partially penetrates into the sheet layer interior, and is cured to form an encapsulation structure. The setting method is not limited and can be coating, perfusion, etc.

[0050] The above encapsulation materials such as insulating materials, resin materials, polymers, etc. can also be compounded with other auxiliary additives to form a composite encapsulation material to improve its encapsulation effect.

[0051] In some embodiments, the encapsulation material of the encapsulation structure 20 further includes auxiliary additives, and the auxiliary additives include one or more of compatibilizers, coupling agents, surfactants, and inorganic fillers. Among them, the types of compatibilizers, coupling agents, surfactants, and inorganic fillers are not limited, and reference can be made to the subsequent relevant content.

[0052] In some embodiments, the encapsulation material further includes auxiliary additives, wherein the mass percentage content of the auxiliary additives is 20% - 60%. Controlling the dosage of the auxiliary additives ensures the encapsulation effect. Optionally, the mass percentage content of the auxiliary additives is 20% - 50%. Optionally, the mass percentage content of the auxiliary additives is 20% - 40%. Optionally, the mass percentage content of the auxiliary additives is 20% - 30%. When there are multiple auxiliary additives, the ratio of each auxiliary additive is not limited.

[0053] Optionally, when the auxiliary additives include organic additives such as compatibilizers, coupling agents, surfactants, etc., the organic additives include polymers containing one or more polar functional groups such as ester groups, carboxyl groups, acid anhydride groups, amide groups, amino groups, hydroxyl groups, and epoxy groups. The organic additives containing the above specific polar functional groups can further improve the permeability of the encapsulation material and more effectively penetrate into the sheet layer interior.

[0054] For example, the compatibilizer includes but is not limited to maleic anhydride grafted polyolefin (MAH-g-PO / PP / PE), epoxy modified polyolefin, etc.; the coupling agent includes but is not limited to γ-aminopropyltriethoxysilane, etc.

[0055] An embodiment of the present disclosure provides a hot-melt resin material, which, by mass fraction, includes: 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. Among them, the matrix resin includes a polymer containing one or more polar functional groups among ester groups, carboxyl groups, acid anhydride groups, amide groups, amino groups, hydroxyl groups, and epoxy groups.

[0056] The melting point of the hot-melt resin material of this embodiment is 60-100 °C, the melt index is 200-400 g / 10 min, and the melt viscosity is 2000-12000 mPa·s; the contact angle with the surface of the battery electrode sheet is ≤60°.

[0057] The fluidity, permeability of the hot-melt resin material of the embodiment of the present disclosure after melting and the mechanical strength after curing are adjustable, and it can be reshaped under the action of temperature and / or vibration, enhancing the interaction with active substances, binders, etc. inside the electrode sheet of the laminated structure 10, improving the interfacial contact, and enhancing the bonding force with the foil material and the active substance area. At the same time, the contact angle between the hot-melt resin material of the embodiment of the present disclosure and the surface of the battery electrode sheet is ≤60°, which can quickly spread and fill the voids between the layers, and more easily penetrate into the interior of the layers, realizing contact and penetration with the substances inside the layers (for example, active substances, binders, etc. of the electrode sheet), and improving the bonding strength of the packaging structure.

[0058] The hot-melt resin material of the embodiment of the present disclosure can be obtained by mixing each component. During use, it is heated to the melting point until it becomes a fluid, making it have fluidity and permeability.

[0059] In the hot-melt resin material of some embodiments, 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 the matrix resin has better surface contact with the positive and negative active substances and the polymer binder, and is more likely to penetrate to form a stable contact.

[0060] Optionally, by weight fraction, the matrix resin is 40 parts, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, or 80 parts, or any number of parts within the range of 40-80 parts.

[0061] In the hot-melt resin material of some embodiments, 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 the compatibilizer has better surface contact with the positive and negative active substances and the polymer binder, and is more likely to penetrate to form a stable contact.

[0062] Optionally, by weight, the compatibilizer is 5 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts, or any number of parts within the range of 5 to 10 parts.

[0063] In the hot-melt resin material of some embodiments, 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 large reduction in the ionic conductivity of the electrolyte.

[0064] In the hot-melt resin material of some embodiments, the coupling agent includes a titanate coupling agent. Optionally, the titanate coupling agent is selected from isopropyltriisostearoyl titanate and / or isopropyl dioleoyl titanate. In this embodiment, the titanate coupling agent has relatively high chemical stability to the solid electrolyte and will not cause a large reduction in the ionic conductivity of the electrolyte.

[0065] Optionally, by weight, the coupling agent is 1 part, 2 parts or 3 parts, or any number of parts within the range of 1 to 3 parts.

[0066] Optionally, the compatibilizer and / or the coupling agent are selected from polymers containing one or more polar functional groups among ester groups, carboxyl groups, acid anhydride groups, amide groups, amino groups, hydroxyl groups, and epoxy groups. The compatibilizer and / or the coupling agent containing the above specific polar functional groups can further improve the permeability of the encapsulating material and penetrate more effectively into the interior of the sheet. For example, the compatibilizer includes, but is not limited to, maleic anhydride grafted polyolefin (MAH-g-PO / PP / PE), epoxy modified polyolefin, etc.; the coupling agent includes, but is not limited to, γ-aminopropyltriethoxysilane, etc.

[0067] In the hot-melt resin material of some embodiments, the inorganic filler is selected from one or more of barium sulfate, titanium dioxide, talc, bentonite, quartz sand, alumina, calcium carbonate, glass powder, zinc oxide. In this embodiment, the inorganic filler can increase the strength and filling ability of the hot-melt resin material, and the types of inorganic fillers in this embodiment can also have better surface contact with the positive and negative active materials and the polymer binder and are more likely to penetrate to form a stable contact.

[0068] In the hot-melt resin material of some embodiments, the particle size of the inorganic filler is 20 to 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, zinc oxide.

[0069] Optionally, the inorganic filler includes alumina nanoparticles with a particle size of 20 to 50 nm.

[0070] Optionally, by weight, the inorganic filler is 1 to 60 parts. 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.

[0071] Optionally, a hot-melt resin material, by weight, includes: 50 to 80 parts of a matrix resin, 6 to 10 parts of a compatibilizer, 2 to 3 parts of a coupling agent, and 10 to 50 parts of an inorganic filler.

[0072] Optionally, a hot-melt resin material, by weight, includes: 60 to 80 parts of a matrix resin, 8 to 10 parts of a compatibilizer, 2 to 3 parts of a coupling agent, and 10 to 30 parts of an inorganic filler.

[0073] Optionally, a hot-melt resin material, by weight, includes: 70 parts of a matrix resin, 10 parts of a compatibilizer, 3 parts of a coupling agent, and 17 parts of an inorganic filler.

[0074] In the battery cell of the embodiment of the present disclosure, the encapsulation structure 20 is obtained by curing the encapsulation material. The permeability of the encapsulation material is positively correlated with the heating temperature of the encapsulation material, that is, the higher the heating temperature, the better the fluidity of the encapsulation material and the better the permeability.

[0075] In the battery cell of the embodiment of the present disclosure, the specific structures and compositions of the negative electrode sheet 11, the solid electrolyte layer 12, and the positive electrode sheet 13 are not limited and are determined according to actual situations.

[0076] Optionally, a negative electrode sheet 11 includes a negative electrode active material layer 111 and a negative electrode current collector layer 112, and the negative electrode active material layer 111 is disposed on the negative electrode current collector layer 112. Among them, one or both sides of the negative electrode current collector layer 112 are covered with the negative electrode active material layer 111, which is determined according to actual needs.

[0077] In this embodiment, the negative electrode current collector layer 112 is usually made of a metal 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 within 6 to 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 a copper foil with a thickness of 6 to 10 μm.

[0078] 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 additive substances, and the other additive substances include one or more composites of components such as pure silicon materials, graphite materials, carbon materials, silicon-carbon materials, and silicon-oxygen materials.

[0079] Optionally, a negative electrode sheet includes a negative electrode active material layer. That is, the negative electrode sheet of this embodiment is only composed of the negative electrode active material layer 111. The negative electrode active material layer 111 is designed to reversibly accommodate and release lithium ions and can play the role of external conduction, and there is no need for the negative electrode current collector layer 112 to provide the conduction function. At this time, the negative electrode active material layer 111 is composed of one or more composites of conductive materials such as lithium metal and carbon materials.

[0080] Optionally, a positive electrode sheet 13 includes a positive electrode active material layer 131 and a positive electrode current collector layer 132, and the positive electrode active material layer 131 is arranged on the positive electrode current collector layer 132. Among them, one or both sides of the positive electrode current collector layer 132 are covered with the positive electrode active material layer 131, which is determined according to actual needs.

[0081] In this embodiment, the positive electrode current collector layer 132 is usually composed of a metal 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 within 6 - 20 μm. Optionally, the thickness of the positive electrode current collector layer 132 is 10 - 20 μm. Optionally, the positive electrode current collector layer 132 includes an aluminum foil with a thickness of 10 - 20 μm.

[0082] Optionally, the positive electrode active material layer 131 is mainly composed of one or more composites of lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium manganate, lithium nickel manganate, lithium-rich manganese-based, lithium iron manganese phosphate, lithium nickel cobalt aluminate, lithium nickel cobalt manganate, lithium iron phosphate, lithium vanadium phosphate, sulfur, lithium sulfide, and lithium iodide sulfide.

[0083] In the battery cell of the embodiment of the present disclosure, the solid electrolyte layer 12 connects the negative electrode active material layer 111 and the positive electrode active material layer 131 to each other and provides the function of lithium ion transmission. The solid electrolyte layer 12 is obtained by compounding one or more of components such as sulfide electrolytes, oxide electrolytes, polymer electrolytes, and halide electrolytes. Preferably, the solid electrolyte layer 12 is a sulfide electrolyte, selected from one or a combination of lithium phosphorus chlorine sulfur, lithium phosphorus bromine sulfur, lithium phosphorus iodine sulfur, lithium phosphorus silicon sulfur, lithium phosphorus aluminum sulfur, lithium phosphorus germanium sulfur, lithium phosphorus boron sulfur, lithium phosphorus sulfur, lithium silicon sulfur, and lithium silicon indium sulfur.

[0084] Combined Figure 5 As shown, the embodiment of the present disclosure provides a packaging method for a battery cell, including the following steps: S110: Stack the positive electrode sheet, the solid electrolyte layer, the negative electrode sheet, and the solid electrolyte layer in this order to obtain a stacked structure; wherein, a sheet layer gap is formed on the circumferential side surface of the stacked structure.

[0085] S120. Set a packaging material into the voids between the laminations of the laminated structure to obtain an electric cell with a packaging structure; wherein, the packaging material can penetrate into the laminations surrounding the voids between the laminations to form a penetration part.

[0086] In the electric cell packaging method of the embodiments of the present disclosure, first, a positive electrode sheet, a negative electrode sheet, and a solid electrolyte layer are stacked in a specific order to obtain a laminated structure, and then a packaging material is set into the voids between the laminations of the laminated structure. Compared with the existing method that requires insulation treatment on a single lamination (such as a positive electrode sheet), the electric cell packaging method of the embodiments of the present disclosure is more practical. It can use continuously coated electrode sheets, be compatible with the overhang design and size design of the positive electrode sheet and the negative electrode sheet, and can simplify the short-circuit prevention treatment of the edge of a single electrode sheet into the edge short-circuit prevention packaging of the laminated structure, greatly reducing the difficulty, cycle, and cost of the battery manufacturing process.

[0087] In the electric cell packaging method of the embodiments of the present disclosure, in step S110, the positive electrode sheet, the solid electrolyte layer, and the negative electrode sheet can all be obtained by conventional methods respectively, which are not limited herein. Among them, the sizes of the positive electrode sheet and the negative electrode sheet can be of equal size design, or the overhang design in which at least one side of the circumferential direction of the negative electrode sheet is larger than that of the positive electrode sheet.

[0088] In step S120, there is no limit to the manner of setting the packaging material into the voids between the laminations of the laminated structure, as long as the packaging paste can be set in the voids between the laminations and penetrate into the surrounding laminations. In some embodiments, setting the packaging material into the voids between the laminations of the laminated structure includes: setting the packaging material into the voids between the laminations of the laminated structure by using a 3D printing method, a perfusion method, or a filling method.

[0089] Optionally, use a 3D printing method to print and set the packaging material into the voids between the laminations of the laminated structure. Compared with other methods, through 3D printing technology for the edge packaging of the electric cell of a laminated solid-state battery, the amount of deposited material can be accurately controlled. When introducing the packaging material into the circumferential side surface and the voids between the laminations of the laminated structure, an appropriate amount of packaging material can be accurately delivered according to the requirements of different positions. At the same time, the non-contact 3D printing manufacturing technology will not cause mechanical damage to the electrode sheets. Moreover, the 3D printing method can construct a support structure within a micron-level gap, so as to effectively ensure the filling rate of the interlayer voids and enable the packaging material to penetrate deep into the voids between the laminations and into the surrounding laminations, thereby more effectively solving the edge stress concentration problem during the pressurized manufacturing or high-voltage operation of the solid-state electric cell. Moreover, the 3D printing method has high processing efficiency and high material utilization rate, and can take into account the permeability and anti-overflow problems of the fluid-like packaging material during the printing process. In the embodiments of the present disclosure, in the 3D printing method, the printing path and printing parameters are set according to the actual situation, which are not limited.

[0090] In some embodiments, in step S120, setting an encapsulation material into the voids between the laminations of the lamination structure includes: setting a first permeable encapsulation material into the voids between the laminations of the lamination structure to obtain a first lamination structure having a first encapsulation layer; wherein, the first encapsulation layer has a penetration portion that penetrates into the laminations surrounding the voids between the laminations and a first filling portion located in the voids between the laminations, and the thickness of the first filling portion is less than the depth of the voids between the laminations. Setting a second permeable encapsulation material into the voids between the laminations of the first lamination structure to obtain a second encapsulation layer outside the first encapsulation layer and obtain an encapsulated lamination structure; wherein, the outer surface of the second encapsulation layer is flush with the circumferential side surface of the lamination structure, or the second encapsulation layer protrudes from the circumferential side surface of the lamination structure and forms a covering portion that covers the circumferential side surface of the lamination structure; and, the penetration ability of the second permeable encapsulation material is less than the penetration ability of the first permeable encapsulation material.

[0091] The battery cell encapsulation method of this embodiment is defined as a dynamic regulation encapsulation method. First, by using a first permeable encapsulation material with better penetration ability for filling and setting, the encapsulation material can penetrate into the laminations surrounding the voids between the laminations, and then a second permeable encapsulation material with low penetration ability is used to continue to completely fill the voids between the laminations, so that the depth of the encapsulation material penetrating into the laminations can be controllably controlled, which not only ensures the interface bonding effect of deep penetration but also can avoid edge overflow defects and form a dense and pore-free encapsulation structure 20.

[0092] In this embodiment, the first permeable encapsulation material and the second permeable encapsulation material can be made of the same material or different materials. For example, both the first permeable encapsulation material and the second permeable encapsulation material are made of the aforementioned hot-melt resin material.

[0093] The penetration ability of the first permeable encapsulation material and the second permeable encapsulation material can be achieved by heating temperature, that is, the first permeable encapsulation material and the second permeable encapsulation material use a resin material whose penetration performance (fluidity) can change according to temperature. Optionally, the first permeable encapsulation material is an encapsulation material heated to a first temperature, and the second permeable encapsulation material is an encapsulation material heated to a second temperature, and the first temperature is greater than the second temperature. In this embodiment, the first temperature and the second temperature are selected from temperature values within the melting point range of the encapsulation material. Optionally, the first temperature is selected from a first sub-temperature range near the high-temperature end within the melting point range of the encapsulation material; the second temperature is selected from a second sub-temperature range near the low-temperature end within the melting point range of the encapsulation material. The first sub-temperature range and the second sub-temperature range can partially overlap.

[0094] Optionally, the first permeable encapsulation material is obtained by heating the aforementioned hot-melt resin material to 80°C to 100°C; and / or, the first permeable encapsulation 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 make it melt into a fluid.

[0095] In the dynamic regulation encapsulation method of this embodiment, during the encapsulation process, the regulation of the penetration performance of the encapsulation material is involved. For example, the penetration performance of the encapsulation material is regulated by regulating the temperature. Therefore, a device / equipment capable of regulating the discharging temperature can be used for encapsulation.

[0096] Optionally, the 3D printing method or the perfusion method is used for the dynamic regulation encapsulation method. In this embodiment, a 3D printing device or a glue filling machine is used for the dynamic regulation encapsulation method.

[0097] In one example, a 3D printing device is used to set the encapsulation material into the layer voids of the laminated structure by the 3D printing method for the dynamic regulation encapsulation method. Among them, the 3D printing device can adopt a 3D printing device including one discharging head (for example, a single-nozzle 3D printing device) or multiple discharging heads (for example, a multi-nozzle 3D printing device). Optionally, a multi-nozzle 3D printing device is used to set the encapsulation material into the layer voids of the laminated structure for dynamic encapsulation. Among them, the first discharging head (the first printing head) is used to output the first permeable encapsulation material, and the second discharging head (the second printing head) is used to output the second permeable encapsulation material. During the 3D printing process, the printing path and printing parameters (such as printing speed, layer height, line width, printing head aperture, etc.) are determined according to the actual situations such as the depth and width of the layer voids and the encapsulation material, and are not limited. For example, the printing speed is 25 - 45 mm / s, the layer height is 10μm - 30μm, and the line width is 80 - 120μm.

[0098] In the 3D dynamic regulation 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 line trajectory.

[0099] In another example, a glue filling machine is used to set the encapsulation material into the layer voids of the laminated structure by the perfusion method for the dynamic regulation encapsulation method. Among them, the glue filling machine can adopt a glue filling machine including one discharging head (for example, a single-nozzle glue filling machine) or multiple discharging heads (for example, a multi-nozzle glue filling machine). Optionally, a multi-nozzle glue filling machine is used to set the encapsulation material into the layer voids of the laminated structure for dynamic encapsulation. Among them, the first discharging head (the first glue discharging needle) is used to output the first permeable encapsulation material, and the second discharging head (the second glue discharging needle) is used to output the second permeable encapsulation material. During the perfusion process, the perfusion parameters (such as perfusion speed, discharging amount, discharging head aperture, etc.) are determined according to the actual situations such as the depth and width of the layer voids and the encapsulation material, and are not limited.

[0100] Different discharging nozzles adopt different heating temperatures, and the discharging nozzles are rotated in cooperation with the printing path. Different discharging nozzles can be connected to different material cylinders, and different formula encapsulation materials can be placed in different material cylinders. During initial use, a discharging nozzle connected to a highly permeable hot melt resin is used for printing / infusion to strengthen the connection strength between the encapsulation structure and the edge of the battery cell. Subsequently, a discharging nozzle connected to a hot melt resin material with low permeability and low fluidity is used for processing to avoid bleeding at the edge.

[0101] In some embodiments, in step S120, setting the encapsulation material into the layer voids of the stacked structure includes: setting the encapsulation material into the layer voids of the stacked structure layer by layer in a layer-by-layer setting manner. In this embodiment, the layer-by-layer setting method is adopted to facilitate the control of the thickness and uniformity of the encapsulation structure. This embodiment can be carried out by using a 3D printing method or an infusion method.

[0102] The layer-by-layer setting method of this embodiment can be combined with the aforementioned dynamic regulation encapsulation method, that is, the layer-by-layer setting method of this embodiment is respectively adopted for the setting of the first permeable encapsulation material and the second permeable encapsulation material.

[0103] Optionally, the encapsulation material includes an encapsulation material whose permeability is positively correlated with temperature; then setting the encapsulation material into the layer voids of the stacked structure includes: setting the encapsulation material into the layer voids of the stacked structure layer by layer in a layer-by-layer setting manner, and from the inner layer to the outer layer, the heating temperature of the encapsulation material decreases. This embodiment can be carried out by using a 3D printing method or an infusion method. In this embodiment, when first printing on the circumferential side of the stacked battery 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 so as to better fill the voids and permeate the material area. When thickening the printing, 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, by adopting a dynamic temperature regulation battery cell encapsulation method, it is possible to better realize the penetration of the encapsulation structure 20 into the layers, and regulate the fluidity of the encapsulation material and the penetration ability by controlling the heating temperature, so as to be able to controllably adjust the penetration depth of the penetration part 210 and ensure the improvement of battery performance.

[0104] In the battery cell encapsulation method of the embodiments of the present disclosure, in step S120, while "setting the encapsulation material into the layer voids of the stacked structure", it further includes: obtaining penetration information that can reflect the penetration situation of the encapsulation material; adjusting the penetration ability of the encapsulation material according to the penetration information. In this embodiment, by providing real-time feedback on the penetration situation of the encapsulation material, the self-adaptive regulation of the penetration ability (fluidity) of the encapsulation material is realized, which can effectively control the penetration depth of the encapsulation material, and further ensure the improvement of battery performance.

[0105] Optionally, the infiltration information that can reflect the infiltration of the first permeable encapsulation material includes: infrared imaging image information. In this embodiment, infrared imaging is used to monitor the flow state and path of the encapsulation material (hot-melt resin material) in real time, and the heating temperature is dynamically adjusted.

[0106] In the encapsulation method of the embodiments of the present disclosure, during the process of setting the encapsulation material in the voids of the sheet layer, the encapsulation material starts to cool and solidify, and after the encapsulation is completed, the laminated structure after encapsulation (the laminated structure provided with the encapsulation material) is placed for a period of time to solidify and form, obtaining an electric core with an encapsulation structure.

[0107] In some embodiments, in step S120, after "setting the encapsulation material in the void area of the laminated structure", it further includes: a step of hot pressing the laminated structure provided with the encapsulation material. In this embodiment, the laminated structure provided with the encapsulation material is hot pressed to strengthen the bonding between the encapsulation material (for example, hot-melt resin material) and the cavity at the edge of the electrode sheet, refill the microscopic depressions on the surface of the electrode sheet (such as cracks less than 5 μm), and reduce the interfacial void ratio; at the same time, by adding this hot pressing step, the contact of each solid-solid interface in the electric core can be improved, and by repairing the poor contact interface, the problem of lithium dendrite growth can be alleviated, the ion transport path can be shortened, etc. The hot pressing treatment of this embodiment can be defined as secondary curing treatment.

[0108] Optionally, hot pressing the laminated structure provided with the encapsulation material includes: placing the laminated structure provided with the encapsulation material on a heating plate at a first preset temperature and processing for a first preset time. The hot pressing treatment of this embodiment is denoted as the first type of hot pressing treatment, where the pressure is the self-pressure of the laminated structure provided with the encapsulation material.

[0109] Optionally, hot pressing the laminated structure provided with the encapsulation material includes: placing the laminated structure provided with 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 of this embodiment is denoted as the second type of hot pressing treatment.

[0110] Optionally, hot pressing the laminated structure provided with the encapsulation material includes: placing the laminated structure provided with 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 of this embodiment is denoted as the third type of hot pressing treatment.

[0111] Optionally, hot pressing the laminated structure provided with the encapsulation material includes: placing the laminated structure provided with 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 of this embodiment is denoted as the fourth type of hot pressing treatment.

[0112] In the first to fourth hot pressing processes, the first preset temperature only needs to be able to soften the encapsulation material again to have a certain fluidity. It can be understood that a heating groove is provided on the heating plate, and the contour of the groove body of the heating groove is consistent with the outer contour of the stacked structure provided with the encapsulation material. When the stacked structure provided with the encapsulation material is placed in the heating groove, the inner wall of the heating groove body can define the stacked structure, that is, it can prevent the laminates from slipping and misaligning when pressure is applied, and can also prevent the encapsulation material softened by reheating from flowing out of the laminate gaps. Optionally, the first preset temperature is greater than or equal to T min and less than or equal to T′, where T′ = T min + δ × (T max - T min ), where T max is the upper limit value of the melting point range of the encapsulation material, T min is the lower limit value of the melting point range of the encapsulation material, and the value range of δ is [0, 1 / 3]. The specific value of δ is determined according to the melting point range of the encapsulation material, that is, the first preset temperature is the lower limit value of the melting point range of the encapsulation material or a certain temperature higher than the lower limit value, which can make the encapsulation material soften and have a certain fluidity. Optionally, δ is 0, 1 / 5, 1 / 4 or 1 / 3, etc.

[0113] Optionally, the first preset temperature is 60°C to 70°C. Optionally, the first preset temperature is 60°C.

[0114] Optionally, the first preset time is 20s to 60s. Optionally, the first preset time is 20s to 50s. The first preset time is 20s to 40s. The first preset time is 30s.

[0115] Optionally, a hot pressing device is used to perform hot pressing on the stacked structure provided with the encapsulation material. Refer to Figure 7 as shown, a hot pressing device 30 includes a heating plate 31 and a pressing plate 32. A heating groove 310 is provided on the heating plate 31, and the cavity of the heating groove 310 is consistent with the outer contour of the stacked structure provided with the encapsulation material. The pressing plate 32 is movably arranged above the heating plate 31, and the pressing plate 32 can be buckled onto the heating plate 31 to apply pressure to the stacked structure placed in the heating groove 310.

[0116] Optionally, a buffer structure is provided at the bottom of the heating groove 310. It provides flexible support for the stacked structure provided with the encapsulation material placed in the heating groove 310 to protect the stacked structure. In this embodiment, the buffer structure can be a buffer gasket, for example, a buffer gasket with elastic deformability such as a rubber gasket, a silica gel gasket, or a latex gasket. It can also be a support plate structure connected to the bottom wall of the heating groove 310 through a damping member, and the damping member can be a spring.

[0117] Optionally, a pressing convex surface adapted to the shape of the heating groove 310 is provided on the pressing surface of the pressing plate 32 for directly pressing the stacked structure placed in the heating groove 310.

[0118] Optionally, a pressure sensor is provided on the pressing plate 32 to provide real-time feedback on the pressure applied to the stacked structure and ensure that an appropriate pressure is applied. Optionally, the pressure sensor is arranged on the pressing convex surface provided on the pressing surface of the pressing plate 32.

[0119] During the hot pressing process, an appropriate pressure is applied to promote the flow and filling of the encapsulating material, enhance the interaction between the encapsulating material and the active substances, binders, etc. in the electrode sheet, and improve the bonding strength.

[0120] Optionally, the method of applying pressure includes applying a constant pressure or a gradient pressure.

[0121] Optionally, the constant pressure is selected from 0.3 to 0.5 MPa.

[0122] Optionally, the gradient pressure is applied in a manner of increasing pressure gradient. Optionally, the pressure range of the gradient pressure is 0.3 to 3 MPa. Optionally, applying the gradient pressure includes: applying a low pressure of 0.3 to 0.5 MPa for a first preset time and then increasing the pressure to a high pressure of 1 to 3 MPa for a first preset time.

[0123] During the hot pressing process, vibration is increased to further induce the encapsulating material to penetrate and locate at the pores at the edge of the electrode sheet, increase the interfacial adhesion strength, and avoid the problem of fragmentation 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 to 50 Hz and an amplitude less than or equal to 50 μm.

[0124] Optionally, when vibration is applied, the vibration includes: gradient stepwise vibration. In this embodiment, the gradient stepwise vibration is applied in a manner of increasing the vibration frequency gradient. Optionally, in this embodiment, the range of the gradient stepwise vibration is 20 Hz to 2000 Hz, and the gradient stepwise vibration is performed by increasing from low frequency to high frequency within this range.

[0125] Optionally, applying the gradient stepwise vibration includes: processing for a first preset time under low-frequency vibration of 20 Hz to 50 Hz, and then increasing the vibration to high-frequency vibration of 500 Hz to 2000 Hz for a first preset time.

[0126] Optionally, the hot pressing device 30 further includes a vibration structure 311 for applying vibration to the stacked structure arranged on the heating plate 31. The form of the vibration structure is not limited. The vibration structure 311 is arranged on the heating plate 31 to apply vibration to the stacked structure placed in the heating groove 310.

[0127] Optionally, the vibration structure 311 includes a flexible vibrating disk, which is disposed in the heating groove of the heating plate 31, or the heating plate 31 is disposed on the flexible vibrating disk. The flexible vibrating disk includes a vibrating disk having a buffer structure on the disk surface, making the output vibration gentle and protecting the laminated structure.

[0128] Optionally, the flexible vibrating disk includes a flexible disk body and a vibration element. The vibration output end of the vibration element is disposed on the flexible disk body to output vibration to the flexible disk body; the disk surface of the flexible disk body has a buffer structure. In this embodiment, for the vibration output object being the laminated battery cell structure, the vibration element is an element capable of outputting micro-vibrations such as small amplitude / small vibration frequency.

[0129] Optionally, the vibration element includes an electromagnetic vibrating table, a piezoelectric vibrator, a spring vibration device, a pneumatic vibrator, a hydraulic vibrator, an ultrasonic device, etc. These vibration elements can output micro-vibrations.

[0130] Optionally, the buffer structure on the disk surface of the flexible disk body can be a buffer gasket. For example, buffer gaskets with elastic deformability such as rubber gaskets, silicone gaskets, and latex gaskets. It can also be a support plate structure connected to the bottom wall of the heating groove 310 through a damping member, and the damping member can be a spring.

[0131] Optionally, the hot pressing treatment of the laminated structure provided with the encapsulation material includes: applying a low pressure of 0.3~0.5 MPa and a low-frequency vibration of 20 Hz~50 Hz to the laminated structure provided with the encapsulation material for a first preset time, and then increasing the pressure to a high pressure of 1~3 MPa and a high-frequency vibration of 500 Hz~2000 Hz for a first preset time.

[0132] In one example, as Figure 6 shown, a 3D printing temperature control encapsulation method includes: S210. Stack the positive electrode plate, solid electrolyte layer, negative electrode plate, and solid electrolyte layer in this order to obtain a laminated structure; wherein, a layer gap is formed on the circumferential side surface of the laminated structure.

[0133] S220. Vertically dispose the laminated structure in the printing area of the 3D printing device with the side to be printed facing upward. S230. Obtain the contour entity data of the side to be printed of the laminated structure; obtain a contour three-dimensional model according to the contour entity data; perform slicing processing on the contour three-dimensional model, perform path planning and printing parameter design to obtain printing information. S240. The 3D printing device prints and sets the molten encapsulation material heated to a preset temperature on the side to be printed according to the printing information and the heating temperature of the encapsulation material, completing the encapsulation printing of the side to be printed of the laminated structure to obtain a laminated structure provided with the encapsulation material.

[0134] In this embodiment, the side to be printed of the laminated structure is one of the circumferential sides of the laminated structure. Repeat the above steps to perform encapsulation printing on each side one by one to complete the encapsulation of the laminated structure.

[0135] In step S230 of this embodiment, the solid contour data of the side to be printed includes data that can reflect key structural nodes such as the edges, layers, and layer voids 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 three-dimensional scanner, and at the same time combining the solid parameters of the laminated structure to obtain the solid contour data of the side to be printed. Among them, the solid parameters of the laminated structure include the size of the laminated structure, the number of laminated layers, etc. The side of the laminated structure is not a flat surface and has layer voids. Therefore, the solid contour data includes three-dimensional solid data.

[0136] In step S230, obtaining the contour three-dimensional model according to the contour solid data includes: importing the solid contour data of the side to be printed into three-dimensional modeling software, and modeling to obtain the contour three-dimensional model. The three-dimensional modeling software is not limited. For example, MeshLab, Blender, etc. During the modeling process, the solid contour data can be processed, including removing noise, filling holes, optimizing the mesh, etc., which are not limited.

[0137] Optionally, in step S230, the contour three-dimensional model is sliced by slicing software. Among them, the slicing software generates printing information according to the shape, size, and printing parameters of the model. The printing parameters include printing layer height, filling density, printing speed, print head temperature, printing bed temperature, etc. The printing information includes the printing path and printing parameters. The printing path determines the movement trajectory of the print head. The printing parameters include printing speed, extrusion amount of the material, printing layer height, material heating temperature, print head temperature, etc. Among them, the printing path is output in the form of G-code instructions that can be recognized by the 3D printing device.

[0138] Optionally, the slicing software includes Cura, PrusaSlicer, etc.

[0139] It can be understood that the circumferential sides of the laminated structure include 4 sides in different directions, and each side is a side to be encapsulated.

[0140] Optionally, if the solid contour data of the side to be printed obtained in step S230 is the solid contour data of the side to be printed that is currently facing up in step S220, the printing path obtained in step S230 is the printing path of the side to be printed that is currently facing up; then the 3D printing temperature control encapsulation method further includes: repeating steps S220 to S240 to encapsulate and print the sides to be printed of the stacked structure one by one to complete the encapsulation of the stacked structure; obtaining an encapsulated stacked structure. In this embodiment, in step S220, when encapsulating different sides to be printed, it is necessary to adjust the side to be printed that is facing up. For example, rotate the stacked structure to make the side to be printed face up.

[0141] 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, the printing path obtained in step S230 is the printing path of all sides to be printed of the entire circumferential side. Then, when encapsulating different sides to be printed, it is only necessary to adjust the current side to be printed to face up. For example, rotate the stacked structure to make the side to be printed face up.

[0142] Optionally, in step S240, it further includes: simultaneously controlling the heating temperature of the encapsulation material. Specifically, simultaneously controlling the heating temperature of the encapsulation material includes: according to the obtained penetration information that can reflect the penetration situation of the encapsulation material; adjusting the heating temperature of the encapsulation material according to the penetration information. In this embodiment, by real-time feedback of the penetration situation of the encapsulation material, the self-adaptive control of the heating temperature of the encapsulation material (i.e., the penetration ability and fluidity) is realized, which can effectively control the penetration depth of the encapsulation material, and thus ensure the improvement of battery performance.

[0143] In some embodiments, the 3D printing temperature control encapsulation method further includes: step S250, performing hot pressing on the stacked structure provided with the encapsulation material. In this embodiment, the relevant content of the hot pressing process can be referred to the foregoing relevant content and will not be elaborated here.

[0144] In the encapsulation method of the battery cell according to the embodiment of the present disclosure, after the encapsulation is completed, for example, after step S240 or step S250, the stacked structure provided with the encapsulation material can also be subjected to a compression process, such as isostatic pressing, so that the layers in the stacked structure are pressed and connected to each other.

[0145] In the encapsulation method according to the embodiment of the present disclosure, the operation of placing the stacked structure on the 3D printing device and placing the printed stacked structure provided with the encapsulation material on the hot pressing device can be completed manually or through an automated transfer device, which can be determined according to the actual situation.

[0146] Combined with Figure 8 As shown in the figure, the embodiment of the present disclosure provides a battery cell encapsulation system for implementing the battery cell encapsulation method of any of the foregoing embodiments, including: Precision fluid material coating equipment 41. The precision fluid material coating equipment 41 includes a 3D printing device or a potting machine.

[0147] A conveying and positioning module (not shown in the figure) is used to flip the stacked structure after stacking to a vertical position and then convey it to the working area of the precision fluid material coating equipment 41. Here, the working area refers to the area where coating is performed. For example, the printing area of a 3D printing device and the perfusion area of a potting machine.

[0148] A scanning module 42 is used to scan the contour solid data of the side to be printed of the stacked structure arranged in the working area of the precision fluid material coating equipment 41; A control unit 43 obtains a contour three-dimensional model based on the contour solid data; performs slicing processing on the contour three-dimensional model, conducts path planning and coating parameter (such as printing parameter) design, and obtains coating information (such as printing path and printing parameters); The precision fluid material coating equipment 41 receives the coating information (such as printing path and printing parameters) from the control unit 43, and sets (such as prints or perfuses) the molten encapsulation material heated to a preset temperature on the side to be printed of the stacked structure located in the working area, so that the encapsulation material can penetrate into the interior of the layers around the layer voids to form a penetration part. Thus, an encapsulation structure 20 is formed on the peripheral side surface of the stacked structure 10.

[0149] In the encapsulation system of this embodiment, by setting the conveying and positioning module, the automatic conveying between the stacking process of the stacked structure and the 3D printing device is realized, and the automation of the encapsulation system is achieved. The specific structure of the conveying and positioning module is not limited. For example, the conveying and positioning module includes a manipulator.

[0150] Optionally, the conveying and positioning module includes a manipulator, and the end of the manipulator includes a flexible fixture for clamping the stacked structure. A flexible fixture refers to a fixture with a buffer structure arranged on the clamping surface. Optionally, the buffer structure can be a buffer gasket, such as a rubber gasket, a silicone gasket, a latex gasket, etc., which are buffer gaskets with elastic deformability. This enables a certain buffer force during the clamping process to protect the stacked structure.

[0151] Optionally, the flexible fixture can rotate relative to the main body of the manipulator. In this way, without moving the main body of the manipulator, the flexible fixture rotates to realize the rotation of the stacked structure, so as to adjust different sides to be printed of the stacked structure to face upward during the encapsulation process of the encapsulation method. In this embodiment, the implementation method for enabling the flexible fixture to rotate relative to the manipulator is not limited.

[0152] Optionally, the scanning module 42 adopts a high-precision vision scanner.

[0153] In the cell encapsulation 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 execute the foregoing step S230 to obtain printing information including the printing path and printing parameters.

[0154] In some embodiments, the fluid material precision coating device 41 includes a 3D printing device, and the coating information obtained by the control unit 43 includes the printing path and printing information; the printing information includes one or more of the following: a loop trajectory and / or a straight trajectory; the line width is 80 - 120 μm; the layer height is 5 - 20 μm; the printing speed is 25 - 45 mm / s; the heating temperature is within the melting point range of the encapsulation material; the printing head temperature is 1 - 50 °C higher than the heating temperature; Optionally, when the foregoing hot-melt resin material is used as the encapsulation material, the heating temperature in the printing information is 60 - 100 °C.

[0155] Optionally, when the cell encapsulation system implements the foregoing dynamic regulation encapsulation method, the heating temperature includes a first heating temperature and a second heating temperature, and the first heating temperature is greater than the second heating temperature; the first heating temperature is the heating temperature of the first permeable encapsulation material, and the second heating temperature is the heating temperature of the second permeable encapsulation material. For example, the first heating temperature is selected from 80 °C to 100 °C, and the second heating temperature is selected from 60 °C to 100 °C.

[0156] Optionally, when the cell encapsulation system implements the foregoing dynamic regulation encapsulation method, the printing information may further include a printing temperature curve, and according to the printing temperature curve, the heating temperature and the corresponding printing head temperature are synchronously adjusted, etc.

[0157] In some embodiments, the cell encapsulation system further includes a hot pressing device (as Figure 7 shown), and the hot pressing device is used to perform hot pressing treatment on the stacked structure provided with the encapsulation material; then, the transfer and positioning module is further used to transfer the stacked structure provided with the encapsulation material after printing to the hot pressing device for hot pressing treatment.

[0158] In some embodiments, the transfer and positioning module is further used to transfer the encapsulated cell with the encapsulation structure to the subsequent process.

[0159] It can be understood that the end of the manipulator of the transfer and positioning module may further include a suction cup. After the stacked structure is encapsulated and formed, the encapsulated stacked structure can be picked up and transferred by a pick-up end such as a suction cup. It is convenient for transfer.

[0160] In some embodiments, the encapsulation system of the battery cell further includes an infrared scanning device, which is configured to perform infrared imaging scanning and monitoring on the voids between the sheets of the laminated structure while setting the encapsulation material in the voids between the sheets of the laminated structure, so as to obtain infrared imaging image information and penetration information that can reflect the penetration of the encapsulation material.

[0161] Specific embodiments are given below to specifically illustrate the battery cell, its encapsulation method, encapsulation system, solid-state battery, and hot-melt resin material according to the embodiments of the present disclosure, so as to more clearly illustrate the technical problems, technical solutions, and beneficial effects solved by the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present application and its application.

[0162] For those technologies or conditions not specified in the embodiments, they shall be carried out according to the technologies or conditions described in the literature in the art or according to the product specifications. For reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0163] Embodiment 1 A battery cell includes a laminated structure and an encapsulation structure. The laminated structure includes alternately stacked negative electrode sheets and positive electrode sheets, and a solid electrolyte layer is disposed between adjacent positive electrode sheets and negative electrode sheets. Among them, at least one side of the negative electrode sheet in the circumferential direction extends beyond the positive electrode sheet to form an overhang region, and a hanging void corresponding to the overhang region is formed on the circumferential side surface of the laminated structure. The encapsulation structure includes a filling portion, a penetration portion, and a covering portion. The filling portion is disposed in the hanging void of the laminated structure. The penetration portion is a part that extends from the filling portion and penetrates into the sheets around the hanging void. The covering portion is connected to the filling portion and covers the circumferential side surface of the laminated structure.

[0164] See Figure 1 and Figure 2 As shown, the battery cell of Embodiment 1 includes a plurality of laminated units, and the two surfaces of the laminated structure 10 are negative electrode sheets.

[0165] In the battery cell of this Example 1, the encapsulation structure is formed by filling a molten hot-melt resin material into the overhang voids and partially penetrating into the laminae and then curing. The hot-melt resin material, by mass parts, 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 alumina nanoparticles with a size of 20 - 50 nm. The melting point of this hot-melt resin material is 60 - 100 °C, the melt index is 200 - 400 g / 10min, the melt viscosity is 2000 - 12000 mPa·s; the contact angle with the surface of the battery electrode sheet is ≤60°.

[0166] In this Example 1, for subsequent solid-state battery assembly and battery performance testing, the following negative electrode sheet, positive electrode sheet, and solid electrolyte layer are specifically used.

[0167] Negative electrode sheet: The negative electrode active material layer is prepared by a wet process, and the composition of the negative electrode active material layer is micron silicon:PVDF:VGCF = 95:3:2 by mass ratio; the negative electrode current collector layer uses a copper foil with a thickness of 6 - 10 μm; the size of the negative electrode sheet is 152 mm × 152 mm. Among them, PVDF is polyvinylidene fluoride; VGCF is vapor-grown carbon fiber.

[0168] Positive electrode sheet: The positive electrode active material layer is prepared by a dry process, and the composition of the positive electrode active material layer is NCM:LPSCl:SP:PTFE = 85:10:3:2 by mass ratio, and the positive electrode current collector layer uses an aluminum foil with a thickness of 10 - 20 μm. The size of the positive electrode sheet is 148 mm × 148 mm. Among them, the NCM material refers to lithium nickel cobalt manganese oxide material, the LPSCl solid electrolyte is a thioargentite-type electrolyte, SP is conductive carbon black, and PTFE is polytetrafluoroethylene.

[0169] The solid electrolyte layer is a sulfide electrolyte, selected from one or a combination of several of lithium phosphorus chlorine sulfur, lithium phosphorus bromine sulfur, lithium phosphorus iodine sulfur, lithium phosphorus silicon sulfur, lithium phosphorus aluminum sulfur, lithium phosphorus germanium sulfur, lithium phosphorus boron sulfur, lithium phosphorus sulfur, lithium silicon sulfur, lithium silicon indium sulfur.

[0170] The battery cell of this Example 1 is encapsulated by a 3D temperature control encapsulation method, and the encapsulation method includes the following steps: Stacking operation: Adopting a design of 6 positives and 7 negatives, stack the positive electrode sheet, solid electrolyte layer, negative electrode sheet, and solid electrolyte layer in this order to obtain a stacked structure; among them, the negative electrode sheet circumferentially exceeds the positive electrode sheet to form an overhang region, and the circumferential side surface of the stacked structure forms an overhang void corresponding to the overhang region; the width of the overhang region is 2 mm.

[0171] Place the stacked sheet structure vertically in the printing area of the 3D printing device with the side to be printed facing up.

[0172] Construct the printing path: Use a high-precision vision scanner (accuracy ±5 μm) to visually scan the side to be printed of the stacked sheet structure, identify the positions of the layer voids (the width of the layer voids is approximately 200 - 300 μm), and at the same time combine the solid parameters of the stacked sheet structure (including the size and number of stacked layers of the stacked sheet structure) to obtain the solid contour data of the side to be printed. Import the solid contour data of the side to be printed into 3D modeling software for modeling to obtain a three-dimensional contour model. Use slicing software to slice the three-dimensional contour model. Among them, the slicing software generates printing information according to 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, extrusion amount of the material, printing layer height, material heating temperature, print head temperature, etc. Among them, the movement trajectory includes a spiral trajectory and / or a straight trajectory, etc.

[0173] Printing and encapsulation: The 3D printing device, according to the printing information and the heating temperature of the encapsulation material, uses a non-contact hot melt nozzle (aperture 100 μm), sets the printing temperature to 85 °C (i.e., the heating temperature of the encapsulation material), the initial extrusion pressure to 0.4 MPa, and fills the layer voids along the side of the stacked sheet structure according to the planned printing path and printing parameters (for example, a spiral trajectory or a straight trajectory, line width 80 - 120 μm, layer height 20 μm, printing speed 25 - 45 mm / s). Dynamically adjust the extrusion pressure and path according to the model design until the layer voids are filled. Finally, form a coating layer about 40 μm thick (i.e., the thickness of the coating part) on one side of the stacked sheet structure to complete the encapsulation of one side of the stacked sheet structure. Rotate the stacked sheet structure to make the side to be printed face up, and repeat the above steps to encapsulate each side to be printed of the stacked sheet structure to obtain a stacked sheet structure provided with the encapsulation material.

[0174] Hot pressing treatment: Transfer the stacked sheet structure to a hot pressing device 30 (as Figure 7 shown), apply a pressure of 0.4 MPa, heat at 60 °C for 30 s, and simultaneously start the vibration structure 311 (for example, frequency 30 Hz, amplitude 30 μm) to promote resin penetration. After completion, continue to pressurize to 2 MPa, and adjust the vibration structure 311 to a high-frequency operation mode (for example, 2 kHz), and continue hot pressing at high frequency for 30 s.

[0175] Complete the hot pressing treatment, cool down, and obtain the battery cell.

[0176] The encapsulation method of this Embodiment 1 can adopt an encapsulation system as Figure 8 shown.

[0177] Figure 9a This is a cross-sectional scanning electron microscope photograph of the battery cell of Example 1. Figure 9b This is an EDS elemental analysis photograph of the cross-section of the battery cell of Example 1. As can be seen from Figure 9a and Figure 9b it can be seen that the penetration depth of the molten resin material reaches 200 μm to 300 μm. The sheet layer void filling rate reaches 91.5% as shown by CT tomography. The interfacial bonding force between the resin and the electrode sheet is measured to be 1.2 MPa by a tensile tester (compared with 0.7 MPa for the traditional impregnation process). After encapsulation, the battery cell is tested under a pressure of 20 MPa for 24 h, and there are no cracks at the edges of the electrode sheets.

[0178] In the battery cell of Example 1, the size of the positive electrode sheet is 148 mm × 148 mm, and the maximum penetration depth is 300 μm. Assuming that the capacity of the penetrated part of the positive electrode is completely lost, the single-layer failure area is 177.6 mm 2 , accounting for 0.81% of the total area of the single-layer positive electrode. This shows that even if the glue penetrates into the interior of the electrode sheet, the theoretical capacity reduction is only 0.81%, which is much smaller than the actual capacity improvement of the encapsulation structure for the battery cell capacity. As the electrode size increases, the proportion of the failure area will further decrease, making the embodiments of the present disclosure particularly suitable for large-size battery cells. Therefore, by means of material design, vibration assistance and other measures, the penetration of the hot-melt encapsulation material into the substances inside the sheet layer, especially into the active substances of the electrode sheet and the solid electrolyte layer, is improved, thereby greatly enhancing the stability of the encapsulation structure.

[0179] In Example 1, the processing time for one side of 3D printing encapsulation (i.e., one side to be printed) is <1 min, and the processing time for a single battery cell is 10 min (including printing and hot pressing). The efficiency is more than 3 times higher than that of the traditional process of processing electrode sheets one by one, and the material utilization rate reaches 95%, which is greatly improved compared with the material utilization rate of only 60% - 70% for traditional spraying. Moreover, it is difficult to control the gradient viscosity and quickly switch materials in the traditional spraying and impregnation processes to balance permeability and on-site forming to prevent overflow.

[0180] Example 2 Compared with Example 1, the difference is that in a battery cell of Example 2, the negative electrode sheet and the positive electrode sheet have the same size, there is no overhang area design, and misalignment voids are formed on the circumferential side of the laminated structure due to misalignment of the electrode sheets. Among them, the size of the negative electrode sheet is 148 mm × 148 mm, and the size of the positive electrode sheet is 148 mm × 148 mm. The remaining steps and parameters are the same as those in Example 1.

[0181] For the battery cell structure of Example 2, see Figure 3As shown, the encapsulation structure is mainly used to wrap the burrs generated in the die-cutting process of the negative current collector layer 112 or the positive current collector layer 132, or fill the misalignment gaps generated by misalignment in the stacking process, and penetrate into the sheet layer to enhance the bonding strength to prevent the separation of the insulating layer and the battery cell under large pressure.

[0182] Example 3 Compared with Example 1, the difference is that in combination Figure 4 As shown, in a battery cell of this Example 2, the positive electrode tab and the negative electrode tab are electrode tabs with obvious defects, and the battery cell is assembled. Typical electrode tab defects include burrs generated by die-cutting of the current collector, the electrode tab edge defect being lack of material at the electrode tab edge or fissures at the electrode tab edge. The uneven thickness at the electrode tab edge causes the local pressure distribution to be unbalanced during pressurization, resulting in warping or breakage of the electrode tab. Discontinuous coating will also cause uneven current density distribution in the edge region, and the local high-current region will accelerate the polarization phenomenon, affecting the charge and discharge efficiency and may lead to the formation of lithium dendrites. The local exposure of the current collector may also cause internal short circuits. The remaining steps and parameters are the same as those in Example 1.

[0183] In Example 3, the positive electrode tab and the negative electrode tab used are those that should be screened out and discarded during normal production. In this Example 3, these electrode tabs with obvious defects are used for battery cell assembly. At the same time, obvious misalignment defects in the stacking process section are set. Other processes are the same as those of normal battery cells. Through the encapsulation structure to fill the misaligned protrusions 1301 and misaligned depressions 1302 generated by misalignment in stacking, wrap the burrs 1121 of the current collector, and fill the electrode tab edge defects 1122, thereby greatly improving the survival rate of the solid-state battery cell and improving the production yield and performance consistency of the battery cell.

[0184] Example 4 Compared with Example 1, the difference is that in the 3D temperature control packaging method of the battery cell in this Example 4, a dual-needle 3D printing device is used. The dual-needle 3D printing device has two independently temperature-controlled needles. The first needle (with a pore diameter of 150 μm) is connected to a high-permeability resin cartridge, and the formula is EVA:MAH-g-PP / PE:γ-aminopropyltriethoxysilane:aluminum oxide = 70:10:3:17 (the same hot-melt resin material as in Example 1). The heating temperature is a gradient decreasing temperature from 95 °C to 85 °C, the extrusion pressure is a gradient decreasing pressure from 0.6 MPa to 0.3 MPa, the printing path of the layer voids is planned as a circular trajectory, the line width is 120 μm, the layer height is 20 μm, and the printing speed is 45 mm / s. The second needle (with a pore diameter of 100 μm) is connected to a low-fluidity resin cartridge, with the same formula as above. The heating temperature is a gradient decreasing temperature from 85 °C to 75 °C, the extrusion pressure is kept constant at 0.3 MPa, the covering printing 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. All other steps and parameters are the same as those in Example 1.

[0185] In the packaging method of the battery cell in this Example 4, a two-step printing strategy with two printing heads (i.e., dual needles) is adopted. Through the different permeabilities and fluidities of the packaging material at different heating temperatures, the coordinated optimization of cavity depth filling and surface high-precision forming is realized. Through CT tomographic scanning, it is shown that the filling rate of the layer voids reaches 99.2% (higher than 91.5% of the single-needle scheme in Example 1), and the interfacial bonding force test reaches 1.8 MPa (a 50% increase compared to the single-needle scheme in Example 1).

[0186] Example 5 Compared with Example 4, the difference is that in this Example 5, ethylene-vinyl acetate copolymer (EVA) is used as the packaging material for the battery cell. All other steps and parameters are the same as those in Example 4.

[0187] In the packaging method of the battery cell in this Example 5, a two-step printing strategy with two printing heads (i.e., dual needles) is adopted. Through the different permeabilities and fluidities of the packaging material at different heating temperatures, the coordinated optimization of cavity depth filling and surface high-precision forming is realized.

[0188] Comparative Example 1 Different from Example 1, after the lamination is completed, the processing procedures of printing and packaging and hot pressing of the laminated structure in Example 1 are not carried out, and the laminated structure is directly transferred to subsequent isostatic pressing and other assembly procedures. All other steps and parameters are the same as those in Example 1.

[0189] Comparative Example 2 Different from Example 2, after the lamination is completed, the processing steps of printing and encapsulating and hot pressing the laminated structure in Example 1 are not carried out, and the laminated structure is directly transferred to the subsequent isostatic pressing and other assembly processes. The remaining steps and parameters are the same as those in Example 2.

[0190] Comparative Example 3 Different from Example 3, after the lamination is completed, the processing steps of printing and encapsulating and hot pressing the laminated structure in Example 1 are not carried out, and the laminated structure is directly transferred to the subsequent isostatic pressing and other processes. The remaining steps and parameters are the same as those in Example 3.

[0191] Comparative Example 4 Different from Example 1, after the lamination is completed, the processing step of hot pressing in Example 1 is not carried out. After the laminated structure with the encapsulating material obtained by printing and encapsulating is cooled and solidified, it is transferred to the subsequent isostatic pressing and other assembly processes. The remaining steps and parameters are the same as those in Example 1.

[0192] Comparative Example 5 Different from Example 1, in the printing and encapsulating step, the hot-melt resin material uses ethylene-vinyl acetate copolymer (EVA), and the printing temperature is set at 70 °C. The remaining steps and parameters are the same as those in Example 1.

[0193] In this Comparative Example 5, ethylene-vinyl acetate copolymer (EVA) is directly used as the encapsulating material without compounding. Figure 10a Figure is the cross-sectional scanning electron microscope photograph of the battery cell of Comparative Example 5, Figure 10b is the EDS elemental analysis photograph of the cross-section of the battery cell of Comparative Example 5. As can be seen from Figure 10a and Figure 10b it can be seen that the encapsulation structure formed by using EVA encapsulation has a continuous and flat boundary with the laminated structure sheet layer (active material layer), and there is almost no element diffusion at the interface, only forming a mechanical stacking contact. The measured interfacial bonding strength is only 0.5 MPa. The weak bonding mode and interfacial bonding force are likely to be unable to resist the volume deformation stress of the battery during the isostatic pressing process or charge and discharge process, resulting in problems such as the deformation and shedding of the encapsulation structure similar to Figure 11a and Figure 11b .

[0194] For the battery cells of the above Examples 1 to 5 and Comparative Examples 1 to 5, solid-state batteries were assembled and charge-discharge tests were carried out. The charge-discharge interval 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), and the charge-discharge test performance data obtained are shown in Table 1.

[0195] Table 1

[0196] From the results of the above examples and comparative examples, it can be found that the solid-state battery with an encapsulation structure can effectively avoid the phenomenon of short circuit during the pressurized assembly and operation of the battery. The yield of the battery cores in Example 1 and Example 2 with the encapsulation structure is relatively high, while the yield of the battery cores in Comparative Example 1 and Comparative Example 2 during the manufacturing process is extremely low. Figure 12 The charge-discharge curves of the battery cores in Example 1 and Comparative Example 1 are shown as follows. Figure 13 The following shows the cycling performance of the non-shorted battery cores in Example 1 and Comparative Example 1. It can be seen that even if no short circuit is found during the manufacturing process, the performance of the battery cores is still poor, and the survival rate after cycling is also low. This indicates that during the cycling process, some battery cores will still short circuit due to edge stress, and the capacity performance in subsequent charge-discharge cycles is also poor, which is caused by micro short circuits occurring inside the battery.

[0197] Taking Example 1 as an example, the yield of the battery core improved by the 3D printing encapsulation method of the present invention (from 34% in Comparative Example 1 to 75%), and the average manufacturing cost per single battery core was directly reduced by 41%. Calculated based on an annual production line of 1 GWh solid-state batteries (the nominal capacity of a single battery core is 205 Wh, equivalent to a production volume of 4,878,049 pieces), calculated at an average price of 80 yuan per battery core, the increase in yield by 41% corresponds to a reduction in annual manufacturing cost of more than 600 million yuan; from the perspective of performance evaluation, the 100-week cycling survival rate of 94% compared to 64% in Comparative Example 1 means that the maintenance cost reduction brought by extending the battery life reaches 35% - 40%.

[0198] In Example 3 and Comparative Example 3, defective electrode sheets were selected for battery core assembly. The battery cores in Comparative Example 3 were basically all ineffective, while for the battery cores after treatment in Example 3, the yield of these defective battery cores could be increased to 22%. That is, through the edge insulation encapsulation in the embodiments of the present disclosure, the problem of partial edge defects of the electrode sheets was solved, which will surely play an important role in improving the overall yield of the electrode sheets and the yield of the battery cores during the actual production process.

[0199] Compared with Example 1, Comparative Example 4 lacks the secondary curing and hot pressing step. One of the purposes of this step is to strengthen the filling of the cavity by the hot-melt material to avoid incomplete filling of some cavities. The second purpose is to strengthen the edge contact between the insulation structure and the original bare semi-finished battery cell. Through hot pressing and vibration, the penetration of the resin on the side of the battery cell is enhanced, thereby improving the connection strength between the two. The third purpose is to simultaneously improve the contact of the remaining solid-solid interfaces of the battery cell. Through high-frequency micro-vibration, defects such as poor contact or surface cracks are repaired. From the experimental results, although lacking the secondary curing and hot pressing step can achieve a good short-circuit prevention effect in the initial battery cell manufacturing stage and the initial battery cell manufacturing yield is still relatively high, as the cycles progress, stress such as volume change of the solid-state battery cell may cause the detachment of the insulation structure, thus losing the edge short-circuit prevention measure and resulting in a decrease in the survival rate of the battery cell after cycling. From the electrical performance data, high-frequency micro-vibration can slightly improve the performance of the battery cell such as capacity utilization.

[0200] Through the above detailed elaboration of the embodiments of the present invention, it can be clearly recognized that the solid-state battery cell edge short-circuit prevention packaging method provided by the present application efficiently and precisely solves the key problem of edge short-circuit caused by overhang design in the design of solid-state batteries at the root. While solving the core problem, this method also fully considers various defects that may be left in the previous process sections such as electrode manufacturing and stacking, such as defects on the edge of the electrode, burrs generated on the edge of the foil, and misalignment during the stacking process. These defects are effectively compensated through a reasonable and efficient packaging design. At the same time, the hot-melt material provided by this embodiment has excellent high-penetration performance, can quickly and fully penetrate into each fine part of the edge of the battery cell, closely combine with the structure of the battery cell, and utilize the elastic characteristics of the resin material to effectively relieve the stress generated inside the solid-state battery during actual operation, greatly reducing the risk of battery performance degradation or damage caused by stress problems. Through actual verification, this method significantly improves the yield of battery cell manufacturing, also has excellent performance in terms of battery cell performance, and further enhances the stability, safety, and service life of the battery cell. In summary, the implementation method proposed by the present invention has achieved extremely excellent technical effects in solving the key problem of overhang short-circuit, compensating for previous process defects, relieving operating stress, and improving manufacturing yield and battery cell performance.

[0201] In the embodiments of the present disclosure, the method for determining the battery cell yield is: the open-circuit voltage matches the design value ±0.05V, and the range difference of the direct current internal resistance of the same model battery cells ≤5%.

[0202] In the embodiments of the present disclosure, the differential scanning calorimetry (DSC) is used to measure the melting point of the hot-melt resin material, the melt indexer is used to measure the melt index, and the rotational viscometer is used to measure the viscosity of the material at 180°C as the melt viscosity of the material. The contact angle is measured at 90°C using a high-temperature contact angle meter.

[0203] In the embodiments 1 to 5 of the present disclosure, the designed capacity of the battery cells is 5 Ah soft-pack battery cells.

[0204] In the embodiments of the present disclosure, the steps of assembling the battery cells into solid-state batteries include: isostatic pressing, tab welding, and final encapsulation. Among them, the isostatic pressing parameter in the assembly process is 500 MPa and 15 min, and the remaining assembly processes can adopt conventional operations.

[0205] The above description and the drawings fully illustrate the embodiments of the present disclosure, enabling those skilled in the art to practice them. Other embodiments may include structural, logical, electrical, process, and other changes. The embodiments only represent possible variations. Unless explicitly required, the individual components and functions are optional, and the order of operations can vary. Some parts and features of some embodiments may be included in or replace parts and features of other embodiments. Moreover, the terms used in this application are only for describing the embodiments and are not used to limit the claims. As used in the description of the embodiments and the claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to also include the plural forms. Similarly, the term "and / or" as used in this application refers to any and all possible combinations including one or more of the associated listed items. Additionally, when used in this application, the term "comprise" and its variants "comprises" and / or "comprising" etc. mean the presence of the stated features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or groupings of these. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, or device comprising the element. In this article, what each embodiment focuses on can be the differences from other embodiments, and the same or similar parts among the embodiments can be referred to each other. For the methods, products, etc. disclosed in the embodiments, if they correspond to the method part disclosed in the embodiments, the relevant parts can refer to the description of the method part.

[0206] Those skilled in the art can realize that the units and steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are executed in a hardware or software manner can depend on the specific application and design constraints of the technical solution. The skilled person can use different methods for each specific application to implement the described functions, but such implementation should not be considered to exceed the scope of the embodiments of the present disclosure. The skilled person can clearly understand that for the convenience and brevity of description, the specific working processes of the systems, devices, and units described above can refer to the corresponding processes in the foregoing method embodiments, and will not be elaborated herein.

[0207] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to the embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram may represent a module, a program segment, or a part of code, and the module, program segment, or part of code contains one or more executable instructions for implementing the specified logical function. In some alternative implementations, the functions marked in the block may occur in a different order than marked in the accompanying drawings. For example, two consecutive blocks may actually be executed substantially in parallel, and they may sometimes be executed in the reverse order, which may depend on the functions involved. In the descriptions corresponding to the flowcharts and block diagrams in the accompanying drawings, the operations or steps corresponding to different 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 the reverse order, which may depend on the functions involved. Each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

Claims

1. A battery cell, characterized in that, Comprising: A laminated structure, which includes alternately laminated negative electrode plates and positive electrode plates, and a solid electrolyte layer is disposed between adjacent positive electrode plates and negative electrode plates; A layer gap is formed on the circumferential side surface of the laminated structure; A packaging structure, which includes a filling part and a penetration part. The filling part is disposed in the layer gap of the laminated structure, and the penetration part is the part that extends from the filling part and penetrates into the interior of the layer around the layer gap; the penetration depth of the penetration part is greater than or equal to 1 μm.

2. The battery cell according to claim 1, wherein The penetration depth of the penetration part is greater than or equal to 1 μm and less than or equal to 300 μm; or, the penetration depth of the penetration part is greater than or equal to 10 μm and less than or equal to 300 μm; or, the penetration depth of the penetration part is greater than or equal to 50 μm and less than or equal to 300 μm; or, the penetration depth of the penetration part is greater than or equal to 100 μm and less than or equal to 300 μm; or, the penetration depth of the penetration part is greater than or equal to 150 μm and less than or equal to 300 μm; or, the penetration depth of the penetration part is greater than or equal to 200 μm and less than or equal to 250 μm; and / or The area percentage of the penetration part in the electrode plate is less than or equal to 1%.

3. The battery cell according to claim 1, wherein The packaging material of the packaging structure includes an insulating material; and / or The packaging material of the packaging structure includes a resin material whose permeability can change according to temperature; and / or The packaging material of the packaging structure includes a hot-melt resin material; and / or The packaging material of the packaging structure includes a polymer containing one or more polar functional groups among ester group, carboxyl group, acid anhydride group, amide group, amino group, hydroxyl group and epoxy group.

4. The battery cell according to claim 3, wherein The packaging material further includes auxiliary additives, and the auxiliary additives include one or more of compatibilizers, coupling agents, surfactants and inorganic fillers; and / or The packaging material further includes auxiliary additives, wherein the mass percentage content of the auxiliary additives is 20% - 60%.

5. The battery cell according to any one of claims 1 to 4, wherein The layer gap includes a misalignment gap generated by misalignment when the negative electrode plate, the solid electrolyte layer and the positive electrode plate are laminated and / or a hanging gap corresponding to an overhang area formed by at least one side of the circumference of the negative electrode plate exceeding the positive electrode plate; and / or The packaging structure further includes a covering part, and the covering part is connected to the filling part and covers the circumferential side surface of the laminated structure.

6. A method for encapsulating an electric core according to any one of claims 1 to 5, characterized in that, Comprising: Stack the positive electrode plate, the solid electrolyte layer, the negative electrode plate and the solid electrolyte layer in this order to obtain a laminated structure; wherein, a layer gap is formed on the circumferential side surface of the laminated structure; Set a packaging material in the layer gap of the laminated structure to obtain a battery cell with a packaging structure; wherein, the packaging material can penetrate into the interior of the layer around the layer gap to form a penetration part.

7. The encapsulation method according to claim 6, wherein, Setting a packaging material in the layer gap of the laminated structure includes: Using a 3D printing method, a perfusion method or a filling method to set a packaging material in the layer gap of the laminated structure.

8. The encapsulation method according to claim 6, wherein An encapsulation material is disposed in the sheet gaps of the laminated structure to obtain an encapsulated laminated structure, including: A first permeable encapsulation material is disposed in the sheet gaps of the laminated structure to obtain a first laminated structure having a first encapsulation layer. Among them, the first encapsulation layer has a penetration portion that penetrates into the sheets around the sheet gaps and a first filling portion located in the sheet gaps. The thickness of the first filling portion is less than the depth of the sheet gaps. A second permeable encapsulation material is disposed in the sheet gaps of the first laminated structure to obtain a second encapsulation layer outside the first encapsulation layer, thereby obtaining an encapsulated laminated structure. Among them, 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 that covers the peripheral side surface of the laminated structure. And the penetration ability of the second permeable encapsulation material is less than that of the first permeable encapsulation material.

9. The encapsulation method according to claim 8, wherein The first permeable encapsulation material and the second permeable encapsulation material are made of a resin material whose permeability can change according to temperature; and / or A 3D printing method, a perfusion method or a filling method is used to dispose the encapsulation material in the sheet gap area of the laminated structure; or, a multi-head 3D printing device or a multi-head glue filling machine is used to dispose the encapsulation material in the gap area of the laminated structure. Among them, the first discharge head is used to output the first permeable encapsulation material, and the second discharge head is used to output the second permeable encapsulation material.

10. The encapsulation method according to any one of claims 6 to 9, characterized in that, The encapsulation material includes an encapsulation material whose permeability is positively correlated with temperature. Then, disposing the encapsulation material in the sheet gaps of the laminated structure includes: by a layered setting method, layer by layer disposing the encapsulation material in the sheet gaps of the laminated structure, and from the inner layer to the outer layer, the heating temperature of the encapsulation material decreases.

11. The encapsulation method according to any one of claims 6 to 9, characterized in that, While "disposing the encapsulation material in the sheet gaps of the laminated structure", it also includes: Obtaining penetration information that can reflect the penetration of the encapsulation material; Adjusting the penetration ability of the encapsulation material according to the penetration information.

12. The encapsulation method according to claim 11, wherein The penetration information that can reflect the penetration of the first permeable encapsulation material includes: infrared imaging image information.

13. The encapsulation method according to any one of claims 6 to 9, characterized in that, After "disposing the encapsulation material in the gap area of the laminated structure", it also includes: the step of thermally pressing the laminated structure with the disposed encapsulation material.

14. The encapsulation method according to claim 13, wherein, Thermally pressing the laminated structure with the disposed encapsulation material includes: Placing the laminated structure with the disposed encapsulation material on a heating plate at a first preset temperature and processing for a first preset time; or Placing the laminated structure with the disposed encapsulation material on a heating plate at a first preset temperature, and applying pressure and / or vibration and processing for a second preset time.

15. The encapsulation method according to claim 14, wherein When applying pressure, the pressure application method includes applying a constant pressure, or applying a gradient pressure; or When applying pressure, the pressure includes a constant pressure of 0.3 to 0.5 MPa, or the pressure includes a gradient pressure within the range of 0.3 to 3 MPa; Or When applying vibration, applying a constant pressure, or applying a gradient pressure; Or When vibration is applied, the vibration includes: vibration with a frequency of 10 to 50 Hz and an amplitude less than or equal to 50 μm; or, the vibration includes gradient stepwise vibration within a frequency range of 20 Hz to 2000 Hz.

16. The encapsulation method according to any one of claims 6 to 9, characterized in that, A 3D printing temperature control encapsulation method is obtained by using a 3D printing method to set encapsulation material in the layer void area of the laminated structure, including: Stacking the positive electrode sheet, solid electrolyte layer, negative electrode sheet, and solid electrolyte layer in this order to obtain a laminated structure; wherein, layer voids are formed on the peripheral side surface of the laminated structure; Vertically arranging the laminated structure in the printing area of the 3D printing device with the side to be printed facing upwards; Obtaining the contour solid data of the side to be printed of the laminated structure; obtaining a contour three-dimensional model based on the contour solid data; performing slicing processing on the contour three-dimensional model, conducting path planning and printing parameter design to obtain printing information; The 3D printing device prints and sets the encapsulation material on the side to be printed according to the printing information and the heating temperature of the encapsulation material, completing the encapsulation printing of the side to be printed of the laminated structure, and obtaining a laminated structure provided with the encapsulation material.

17. A packaging system for an electric cell, which is used to implement the packaging method of the electric cell according to any one of claims 6 to 16, characterized in that, Including: Fluid material precision coating equipment; A transfer and positioning module for flipping the laminated structure after lamination to a vertical position and then transferring it to the working area of the fluid material precision coating equipment; A scanning module for scanning the contour solid data of the side to be printed of the laminated structure arranged in the working area of the fluid material precision coating equipment; A control unit that obtains a contour three-dimensional model based on the contour solid data; performs slicing processing on the contour three-dimensional model, conducts path planning and coating parameter design to obtain coating information; The fluid material precision coating equipment receives the coating information from the control unit and sets the molten encapsulation material heated to a preset temperature on the side to be printed of the laminated structure located in the working area, enabling the encapsulation material to penetrate into the layers around the layer voids to form a penetration part.

18. The encapsulation system for the battery cell according to claim 17, characterized in that, It further includes: A hot pressing device, including a heating plate and a pressing plate. A heating groove is provided on the heating plate, and the cavity of the heating groove is consistent with the outer contour of the laminated structure provided with the encapsulation material; The pressing plate is movably arranged above the heating plate and can be buckled onto the heating plate to apply pressure to the laminated structure placed in the heating groove; and / or The hot pressing device further includes a vibration structure for applying vibration to the laminated structure arranged on the heating plate; or, the vibration structure includes a flexible vibration disk, which is arranged in the heating groove of the heating plate, or the heating plate is arranged on the flexible vibration disk; and / or An infrared scanning device for performing infrared imaging scanning and monitoring on the layer voids while setting the encapsulation material in the layer voids of the laminated structure to obtain infrared imaging image information, which is penetration information capable of reflecting the penetration situation of the encapsulation material.

19. The encapsulation system of the battery cell according to claim 17, wherein The coating information includes a coating path and coating parameters; and / or The fluid material precision coating equipment includes a 3D printing device or a glue filling machine; and / or The precision coating equipment for fluid materials includes 3D printing equipment, and 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 linear trajectory; the line width is 80-120 μm; the layer height is 5-20 μm; the printing speed is 25-45 mm / s; The heating temperature is within the melting point range of the encapsulation material; the printing head temperature is 1-50 °C higher than the heating temperature; When the encapsulation material uses the hot-melt resin material as described in claim 21 or 22, the heating temperature in the printing information is 60-100 °C.

20. The encapsulation system for the battery cell according to claim 18, characterized in that When the encapsulation system for the battery cell is used to implement the encapsulation method for the battery cell including claim 8, the heating temperature in the printing information includes a first heating temperature and a second heating temperature and the first heating temperature is greater than the second heating temperature; the first heating temperature is the heating temperature of the first permeable encapsulation material, and the second heating temperature is the heating temperature of the second permeable encapsulation material; When the encapsulation material uses the hot-melt resin material as described in claim 21 or 22, the first heating temperature is selected from 80 °C to 100 °C, and the second heating temperature is selected from 60 °C to 100 °C.

21. A hot-melt resin material, characterized in that, As the encapsulation material for the encapsulation structure of the battery cell according to any one of claims 1 to 5, or, as the encapsulation material in the encapsulation method for the battery cell according to any one of claims 6 to 16; or, as the encapsulation material used for the precision coating of the fluid material of the encapsulation system for the battery cell according to any one of claims 17 to 20; By mass, the hot-melt resin material includes: 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 includes a polymer containing one or more polar functional groups among ester group, carboxyl group, acid anhydride group, amide group, amino group, hydroxyl group and epoxy group.

22. The hot-melt resin material according to claim 21, characterized in that The hot-melt resin material has at least one of the following: the melting point is 60-100 °C, the melt index is 200-400 g / 10min, the melt viscosity is 2000-12000 mPa·s; the contact angle with the surface of the battery electrode is ≤60°; and / or 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 The compatibilizer and / or coupling agent is selected from polymers containing one or more polar functional groups among ester group, carboxyl group, acid anhydride group, amide group, amino group, hydroxyl group and epoxy group; and / or The compatibilizer includes one or more of maleic anhydride grafted polyolefin, epoxy modified polyolefin, polypropylene grafted polystyrene; and / or The coupling agent includes silane coupling agent; and / or The coupling agent includes one or more of γ-aminopropyltriethoxysilane, vinyltrimethoxysilane and vinyltriethoxysilane; and / or The coupling agent includes titanate coupling agent; and / or The coupling agent includes isopropyl triisostearoyl titanate and / or isopropyl dioleoyl titanate; and / or The inorganic filler includes one or more of barium sulfate, titanium dioxide, talc powder, bentonite, quartz sand, alumina, calcium carbonate, glass powder, zinc oxide; and / or aluminum oxide nanoparticles with a particle size of 20 to 50 nm of the inorganic filler.

23. A solid-state battery, characterized in that, Comprising: The battery cell according to any one of claims 1 to 5; or, the battery cell obtained by encapsulating using the encapsulation method of the battery cell according to any one of claims 6 to 16; or, the battery cell obtained by encapsulating using the encapsulation system of the battery cell according to any one of claims 17 to 20.

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