Method for manufacturing composite electrode sheet, manufacturing device, and lithium ion battery

Abstract

The application relates to a preparation method and a preparation device of a composite pole piece and a lithium ion battery. The preparation method comprises the following steps: unwinding at least two rolls of solid electrolyte films according to corresponding preset tensions, and unwinding an electrode pole piece; compositing each roll of the solid electrolyte films on the electrode pole piece in parallel to obtain a composite pole piece; gaps exist between adjacent solid electrolyte films on the composite pole piece; and the composite pole piece is cut along the gaps. At least two rolls of composite pole pieces can be obtained through one-time roll pressing and composition, so that the preparation efficiency of the composite pole piece is multiplied; meanwhile, each roll of the solid electrolyte films is unwound according to the corresponding preset tension, the characteristics of each roll of the solid electrolyte films are better matched, the mutual composition and roll pressing effect of each roll of the solid electrolyte films and the electrode pole piece can be individually controlled, so that the composition effect of each roll of the composite pole piece is improved, the applicability of the preparation process is improved, and the preparation efficiency of the composite pole piece is improved.

Description

Technical Field

[0001] This application relates to the field of electrode preparation technology, and in particular to a method and apparatus for preparing a composite electrode and a lithium-ion battery. Background Technology

[0002] Currently, commercially available lithium-ion batteries are primarily liquid batteries using organic electrolytes. Their high energy density and long cycle life have led to their widespread application in daily life and industrial production. However, the volatility, leakage, and flammability of traditional liquid electrolytes pose serious safety hazards during use. In contrast to traditional liquid lithium-ion batteries, all-solid-state lithium-ion batteries utilize solid electrolytes with excellent thermal stability and safety, and are increasingly being considered the next generation of commercial lithium-ion batteries.

[0003] In the fabrication process of solid-state lithium-ion batteries, there are wet and dry processes. The wet process for electrode preparation, which requires solvents and drying, leads to environmental pollution and energy waste. Based on this, the industry has developed a dry process for electrode preparation. Dry electrode preparation mainly involves mixing powders of active materials, conductive agents, and additives for the positive or negative electrode with binder powder. High shear force is used to fiberize the binder, bonding the mixture together. The mixture is then rolled to form the electrode sheet. In related technologies, dry composite electrode preparation typically involves laminating a solid electrolyte membrane onto an electrode sheet and then winding it up to obtain a composite electrode sheet. Using this method, only one roll of composite electrode sheet can be obtained per lamination operation, resulting in low production efficiency. Furthermore, in related technologies, the pressure rollers can only roll composite electrode sheets of a single size. Different electrode widths require pressure rollers of corresponding widths, necessitating multiple production lines that need to be constantly switched according to product demand, further reducing the production efficiency of composite electrode sheets and the utilization rate of the pressure rollers, leading to resource waste. Summary of the Invention

[0004] Therefore, it is necessary to provide a method, apparatus, and lithium-ion battery for preparing composite electrodes that are highly efficient and widely applicable, in order to address the aforementioned technical problems.

[0005] On the one hand, a method for preparing a composite electrode is provided, including the following steps:

[0006] At least two rolls of solid electrolyte membrane are unwound according to the corresponding preset tension, and the electrode sheets are also unwound.

[0007] Each roll of the solid electrolyte membrane is laminated side by side onto the electrode sheet to obtain a composite electrode sheet; there are gaps between adjacent solid electrolyte membranes on the composite electrode sheet;

[0008] The composite electrode is cut along the gap.

[0009] In one embodiment, the step of unwinding at least two rolls of solid electrolyte membrane at a preset tension for each roll includes: each roll of the solid electrolyte membrane is wound around a corresponding unwinding shaft, and the tension of each roll of the solid electrolyte membrane is adjusted to reach the preset tension by adjusting the unwinding shaft.

[0010] In one embodiment, the step of unwinding at least two rolls of solid electrolyte membrane at corresponding preset tensions further includes: each roll of solid electrolyte membrane being wound on the same unwinding shaft; or, each roll of solid electrolyte membrane being wound on a corresponding unwinding shaft, wherein at least two of the unwinding shafts are spaced apart from each other.

[0011] In one embodiment, the step of cutting the composite electrode along the gap includes the step of: winding up the base film and the composite electrode generated after the solid electrolyte membrane is composited, with each roll of the base film corresponding to each roll of the solid electrolyte membrane;

[0012] Each roll of the base film is wound on the same take-up spool; or, each roll of the film is wound on a corresponding take-up spool, with at least two of the take-up spools spaced apart from each other.

[0013] On the one hand, an apparatus for preparing composite electrodes is provided, comprising:

[0014] The unwinding roller includes a first unwinding roller for winding at least two rolls of solid electrolyte membrane and a second unwinding roller for winding electrode sheets; the first unwinding roller unwinds each roll of solid electrolyte membrane according to a corresponding preset tension.

[0015] The take-up shaft includes a first take-up roller for winding at least two rolls of base film and a second take-up roller for winding composite electrode sheets;

[0016] A composite assembly is disposed between the unwinding shaft and the take-up shaft. The composite assembly is used to combine at least two rolls of the solid electrolyte membrane and the electrode sheet with a preset tension to form the composite electrode sheet.

[0017] In this embodiment, each roll of the solid electrolyte membrane is laminated side by side on the electrode sheet, and there is a gap between adjacent solid electrolyte membranes on the composite electrode sheet.

[0018] In one embodiment, the unwinding shaft is a slip shaft or a split air shaft.

[0019] In one embodiment, the preparation apparatus further includes an adjustment component capable of adjusting the unwinding shaft to adjust the tension of the solid electrolyte membrane during unwinding.

[0020] In one embodiment, an adjustment shaft is provided between the unwinding shaft and the composite component, and the solid electrolyte membrane extending from the unwinding shaft abuts against the adjustment shaft, the adjustment shaft being adjustable to adjust the tension of the solid electrolyte membrane;

[0021] And / or, an adjustment shaft is provided between the take-up shaft and the composite assembly, the base film extending from the composite assembly and / or the composite electrode abutting against the adjustment shaft, the adjustment shaft being adjustable to adjust the tension of the base film and / or the composite electrode.

[0022] In one embodiment, the composite component includes a first pressure roller and a second pressure roller disposed opposite to each other, the solid electrolyte membrane and the electrode sheet passing between the first pressure roller and the second pressure roller to form the composite electrode sheet; the surfaces of the first pressure roller and / or the second pressure roller are made of an elastic material.

[0023] On the one hand, a lithium-ion battery is provided, comprising a composite electrode prepared by the method described above.

[0024] The above preparation method involves simultaneously unwinding at least two rolls of solid electrolyte membrane and rolling each roll of solid electrolyte membrane with one electrode sheet simultaneously. The membrane is then cut along the gap between the composite solid electrolyte membranes to obtain at least two rolls of composite electrode sheets. This single rolling process can simultaneously produce at least two rolls of composite electrode sheets, significantly increasing the preparation efficiency. Furthermore, each roll of solid electrolyte membrane is unwound according to a pre-set tension, better matching the characteristics of each roll. This allows for individual control of the rolling effect between each roll of solid electrolyte membrane and the electrode sheet, thereby improving the composite effect of each roll of composite electrode sheet, enhancing the applicability of the preparation process, and increasing the efficiency of composite electrode sheet preparation. Attached Figure Description

[0025] Figure 1 This is a schematic flowchart of the preparation method in one embodiment of this application.

[0026] Figure 2 This is a schematic diagram of the preparation apparatus in one embodiment of this application.

[0027] Figure 3 This is a front view of the preparation apparatus in one embodiment of this application.

[0028] Figure 4 This is a schematic diagram of the structure of the slip shaft in one embodiment of this application.

[0029] Figure 5 This is a schematic diagram of the structure of the split air shaft in one embodiment of the application.

[0030] Figure 6This is a schematic diagram of the preparation apparatus in Embodiment 1 of this application.

[0031] Figure 7 This is a front view of the preparation apparatus in Embodiment 1 of this application.

[0032] Figure 8 for Figure 7 A sectional view of the AA plane.

[0033] Figure 9 This is a schematic diagram of the preparation apparatus in Embodiment 2 of this application.

[0034] Figure 10 This is a front view of the preparation apparatus in Embodiment 2 of this application.

[0035] Figure 11 for Figure 10 A sectional view of the BB plane.

[0036] Figure 12 This is a schematic diagram of the preparation apparatus in Embodiment 3 of this application.

[0037] Figure 13 This is a front view of the preparation apparatus in Embodiment 3 of this application.

[0038] Figure 14 for Figure 13 A sectional view of the CC plane. Detailed Implementation

[0039] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0040] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0041] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0043] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0045] In this application, the direction parallel to the movement of the electrode plate is defined as the horizontal direction, the direction perpendicular to the movement of the electrode plate is defined as the vertical direction, and the direction perpendicular to both the horizontal and vertical directions is defined as the front-back direction.

[0046] See Figure 1 , Figure 1The diagram shows a flow chart of a method for preparing a composite electrode according to an embodiment of this application. The preparation method provided in an embodiment of this application includes the following steps:

[0047] S100. Unwind at least two rolls of solid electrolyte membrane at the corresponding preset tension, and unwind the electrode sheets.

[0048] S200. Each roll of solid electrolyte membrane is laminated side-by-side onto an electrode sheet to obtain a composite electrode sheet. There are gaps between adjacent solid electrolyte membranes on the composite electrode sheet.

[0049] S300. Cut the composite electrode along the gap.

[0050] By using the above preparation method, at least two rolls of solid electrolyte membrane are simultaneously unwound, and each roll of solid electrolyte membrane is simultaneously rolled and laminated with one electrode sheet. Cutting is then performed along the gaps between the composite solid electrolyte membranes, resulting in at least two rolls of composite electrode sheets. At least two rolls of composite electrode sheets can be obtained in a single rolling and lamination process, thus increasing the preparation efficiency of composite electrode sheets several times over. At the same time, each roll of solid electrolyte membrane is unwound according to a corresponding preset tension, which better matches the characteristics of each roll of solid electrolyte membrane. This allows the mutual lamination effect between each roll of solid electrolyte membrane and the electrode sheet to be controlled individually, thereby improving the lamination effect of each roll of composite electrode sheet, increasing the applicability of the preparation process, and also increasing the efficiency of preparing composite electrode sheets.

[0051] Optionally, the width of each roll of solid electrolyte membrane can be the same or different, or the width of each roll of solid electrolyte membrane can be partially the same and partially different. The material composition of each roll of solid electrolyte membrane can be the same or different, or the material composition of each roll of solid electrolyte membrane can be partially the same and partially different. This can be understood as the solid electrolyte membrane having different material systems or structural compositions, which leads to different lamination processes for each roll of solid electrolyte membrane.

[0052] In some embodiments, the solid electrolyte membrane includes a solid electrolyte and a binder.

[0053] In preparing a solid electrolyte membrane, the solid electrolyte and binder are first stirred and mixed. After the mixture is fiberized, a fiberized solid electrolyte mixture is obtained. The fiberized solid electrolyte mixture is then rolled to obtain a solid electrolyte membrane.

[0054] In some embodiments, the solid electrolyte is an inorganic solid electrolyte, including one or more of oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes, hydride solid electrolytes, boride solid electrolytes, and nitride solid electrolytes.

[0055] The oxide solid electrolyte comprises one or more of garnet ceramics, LISICON-type oxides, NASICON-type oxides and perovskite ceramics. For example, the one or more garnet ceramics include but are not limited to Li 6.5 La3Zr 1.75 Te 0.25 O 12 , Li7La3Zr2O 12 (LLZO), Li 6.2 Ga 0.3 La 2.95 Rb 0.05 Zr2O 12 , Li 6.85 La 2.9 Ca 0.1 Zr 1.75 Nb 0.25 O 12 , Li 6.25 Al 0.25 La3Zr2O 12 , Li 6.75 La3Zr 1.75 Nb 0.25 O 12 one or more of the above. The one or more LISICON-type oxides include but are not limited to Li 14 Zn(GeO4)4, Li 3+x (P 1-x Si x )O4 (where 0<x<1), Li 3+x Ge x V 1-x O4 (where 0<x<1) one or more of the above. The one or more NASICON-type oxides can be defined by LiMM′(PO4)3, wherein M and M′ are each independently selected from Al, Ge, Ti, Sn, Hf, Zr and La. For example, in certain variations, the one or more NASICON-type oxides include but are not limited to Li 1+x Al x Ge 2-x (PO4)3 (LAGP) (where 0≤x≤2), Li 1+x Al x Ti 2-x (PO4)3 (LATP) (where 0≤x≤2), Li 1+ x Y x Zr 2-x (PO4)3 (LYZP) (where 0≤x≤2), Li 1.3 Al 0.3 Ti 1.7(PO4)3, LiTi2(PO4)3, LiGeTi(PO4)3, LiGe2(PO4)3, LiHf2(PO4)3, one or more of them. The one or more perovskite ceramics include but are not limited to Li 3.3 La 0.53 TiO3, LiSr 1.65 Zr 1.3 Ta 1.7 O9, Li 2x-y Sr 1-x Ta y Zr 1-y O3 (wherein x=0.75y and 0.60<y<0.75), Li 3 / 8 Sr 7 / 16 Nb 3 / 4 Zr 1 / 4 O3, Li 3x La (2 / 3-x) TiO3 (wherein 0<x<0.25), one or more of them.

[0056] Sulfide solid electrolytes include but are not limited to Li2S-P2S5, Li2S-P2S5-MS x (wherein M is Si, Ge and Sn and 0≤x≤2), Li 3.4 Si 0.4 P 0.6 S4, Li 10 GeP2S 11.7 O 0.3 , Li 9.6 P3S 12 , Li7P3S 11 , Li9P3S9O3, Li 10.35 Si 1.35 P 1.65 S 12 , Li 9.81 Sn 0.81 P 2.19 S 12 , Li 10 (Si 0.5 Ge 0.5 )P2S 12 , Li(Ge 0.5 Sn 0.5 )P2S 12 , Li(Si 0.5 Sn 0.5 )PsS 12 , Li 10 GeP2S 12 (LGPS), Li6PS5X (wherein X is Cl, Br or I), Li7P2S8I, Li 10.35 Ge1.35 P 1.65 S 12 , Li 3.25 Ge 0.25 P 0.75 S4, Li 10 SnP2S 12 , Li 10 SiP2S 12 , Li 9.54 Si 1.74 P 1.44 S 11.7 C l0.3 , (1-x) P2S 5-x Li2S, wherein 0.5 ≤ x ≤ 0.7, one or more of them.

[0057] Halide solid electrolytes include, but are not limited to, Li2CdC l4 , Li2MgC l4 , Li2Cd I4 , Li2ZnI4, Li3OCl, LiI, Li5ZnI4, Li3OCl 1-x Br x wherein 0 < x < 1, one or more of them.

[0058] Boride solid electrolytes include, but are not limited to, one or more of Li2B4O7 and Li2O-(B2O3)-(P2O5).

[0059] Nitride solid electrolytes include, but are not limited to, one or more of Li3N, Li7PN4, LiSi2N3 and LiPON.

[0060] Hydride solid electrolytes include, but are not limited to, one or more of Li3AlH6, LiBH4, LiBH4-LiX (wherein X is one of Cl, Br and I), LiNH2, Li2NH and LiBH4-LiNH2.

[0061] In some embodiments, the inorganic solid electrolyte may be one or more metal oxide particles or lithium-containing compounds, including but not limited to one or more of Al2O3, SiO2, TiO2, LiNbO3, Li4Ti5O4 and Li3PO4.

[0062] In some embodiments, the solid electrolyte further includes a portion of polymer solid electrolyte, or a composite solid electrolyte composed of polymer solid electrolyte and inorganic solid electrolyte. In the embodiments of this application, the mass ratio of the inorganic solid electrolyte to the polymer solid electrolyte in the composite solid electrolyte is not particularly required; users can design it according to actual needs. The polymer solid electrolyte can be at least one of polyvinyl chloride (PVC), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and polyethylene oxide (PEO).

[0063] In some implementations, the polymer solid electrolyte contains a lithium salt.

[0064] In some embodiments, lithium salts include, but are not limited to, lithium hexafluorophosphate (LiPF6); lithium perchlorate (LiClO4), lithium tetrachloroaluminate (LiAlCl4), lithium iodide (LiI), lithium bromide (LiBr), lithium thiocyanate (LiSCN), lithium tetrafluoroborate (LiBF4), lithium difluorooxalate borate (LiBF2(C2O4))(LiODFB), lithium tetraphenylborate (LiB(C6H5)4), lithium bis(oxalate)borate (LiB(C2O4)2)(LiBOB), lithium tetrafluorooxalate phosphate (LiPF4(C2O4))(LiFOP), lithium nitrate (LiNO3), lithium hexafluoroarsenate (LiAsF6), lithium trifluoromethanesulfonate (LiCF3SO3), lithium bis(trifluoromethanesulfonylimide) (LITFSI)(LiN(CF3SO2)2), lithium bis(fluorosulfonylimide) (LiN(FSO2)2)(LIFSI), and combinations thereof. In some variations, the lithium salt is selected from one or more of lithium hexafluorophosphate (LiPF6), lithium bis(trifluoromethanesulfonylimide) (LiTFSI)(LiN(CF3SO2)2), lithium bis(fluorosulfonylimide) (LiN(FSO2)2)(LiFSI), lithium fluoroalkylphosphonate (LiFAP), and lithium phosphate (Li3PO4).

[0065] It is understood that the terms mentioned above, including oxide solid electrolytes, sulfide solid electrolytes, halide solid electrolytes, hydride solid electrolytes, nitride solid electrolytes, polymer solid electrolytes, etc., are all known in the art. The details of the above materials are merely illustrative examples and not a limitation on the scope of protection. Without departing from the inventive concept of this application, any known type of solid electrolyte can be used in this application.

[0066] In some embodiments, the thickness of the solid electrolyte membrane is 1-40 μm. Solid electrolyte membranes can effectively improve the safety performance of batteries, but if the solid electrolyte is too thick, it will affect the energy density of the battery; it is understood that when the solid electrolyte membrane includes a substrate, the thickness of the solid electrolyte membrane does not include the thickness of the substrate.

[0067] Preferably, the thickness of the solid electrolyte membrane is 1-30 μm; more preferably, it is 3-20 μm; more preferably, it is 3-15 μm. The maximum areal density of the solid electrolyte membrane is 4 mg / cm³. 2 The width can be 0.6m.

[0068] Applying a solid electrolyte coating to the electrode surface, especially the surface of a high-capacity positive electrode, can effectively improve battery safety. However, due to limitations in energy density, the thickness of the solid electrolyte film is usually quite thin. Compared to dry-processed electrode sheets, the thickness of the solid electrolyte film is an order of magnitude smaller, which makes it prone to cracking during the dry-process composite of conductive electrode sheets.

[0069] In some embodiments, the solid electrolyte membrane is formed independently, meaning that the solid electrolyte membrane can be formed without the aid of a substrate and maintain the integrity of the membrane.

[0070] In some embodiments, the solid electrolyte membrane includes a solid electrolyte layer to be laminated onto the electrode sheet and a base film on the side away from the electrode sheet, wherein the adhesion between the base film and the solid electrolyte layer is less than the adhesion between the solid electrolyte layer and the electrode sheet. After rolling, at least a portion of the solid electrolyte layer is transferred to the electrode sheet and separated from the base film.

[0071] This application does not specifically limit the type of base film. Without departing from the inventive concept of this application, any known material that provides support, facilitates the formation of the electrolyte material film, and can separate from the solid electrolyte membrane after rolling can be used in this application. This is merely an illustrative example and not a limitation on the scope of protection. The base film is selected from one or more of the following: silicone oil release film, fluorine release film, PET film, PP film, PE film, PE / PP film, PP / PE / PP film, PE / PP / PE film, and non-silicone release film. This application also provides a composite electrode sheet prepared according to the above-described method for preparing composite electrodes.

[0072] In step S100, the electrode sheet extends horizontally after being unwound, and at least two rolls of solid electrolyte membrane are unwound from the electrode sheet at intervals in the vertical direction. Further, the solid electrolyte membrane and the electrode sheet are unwound around different position axes in at least one of the horizontal and vertical directions.

[0073] In one embodiment, step S100 of unwinding at least two rolls of solid electrolyte membrane and electrode sheet further includes: S110. Each roll of the solid electrolyte membrane is wound on a corresponding unwinding shaft, and the tension of each roll of the solid electrolyte membrane is adjusted to reach a preset tension by adjusting the unwinding shaft.

[0074] Furthermore, the step of adjusting the unwinding shaft also includes at least one of the following steps:

[0075] S111. Adjust the position of the unwinding shaft corresponding to each roll of solid electrolyte membrane to change the tension of each roll of solid electrolyte membrane to achieve the corresponding preset tension.

[0076] S112. Adjust the unwinding speed of the unwinding shaft corresponding to each roll of solid electrolyte membrane to change the tension of each roll of solid electrolyte membrane to achieve the corresponding preset tension.

[0077] S113. An adjustment mechanism is provided to change the tension of each roll of solid electrolyte membrane before and after unwinding, so that the tension of each roll of solid electrolyte membrane reaches the corresponding preset tension.

[0078] In one embodiment, step S100 of unwinding at least two rolls of solid electrolyte membrane and electrode sheet further includes: S120. Each roll of solid electrolyte membrane is wound on the same unwinding shaft, and then each roll of solid electrolyte membrane is unwound on the same unwinding shaft.

[0079] It is understood that the aforementioned "same unwinding roller" refers to each roll of solid electrolyte membrane being unwound coaxially. Each roll of solid electrolyte membrane can be wound on the same unwinding roller or on different unwinding rollers arranged coaxially. When the solid electrolyte membrane is wound on different unwinding rollers arranged coaxially, the different unwinding rollers can be arranged continuously coaxially or intermittently. Coaxial unwinding is particularly suitable when the solid electrolyte membrane material and width are the same, and each roll of solid electrolyte membrane has the same characteristics, such as consistent tension. Coaxial unwinding is beneficial for the bonding of electrode sheets and solid electrolyte membranes.

[0080] In one embodiment, step S100 of unwinding at least two rolls of solid electrolyte membrane and electrode sheet further includes: S130. Each roll of solid electrolyte membrane is wound on a corresponding unwinding shaft, at least two of the unwinding shafts are spaced apart from each other, and then each roll of solid electrolyte membrane is unwound on the corresponding unwinding shaft.

[0081] It is understood that in step S130, a portion of the solid electrolyte membrane is wound on the same unwinding roller, while another portion is wound on unwinding rollers with different axes, or each roll of solid electrolyte membrane is wound on unwinding rollers with different axes. The aforementioned spacing refers to at least two of the unwinding rollers being located at different positions in the vertical, front-back, or horizontal direction. Steps S120 and S130 are different schemes implemented in parallel. The non-coaxial, partially non-coaxial unwinding method in step S130 is particularly suitable when there are differences in the material and width of each roll of solid electrolyte membrane. Due to the differences in width and material, each roll of solid electrolyte membrane has different characteristics, such as inconsistent tension. Using non-coaxial unwinding to match the corresponding characteristics of different rolls of membrane is beneficial for the composite of electrode sheets and solid electrolyte membranes.

[0082] Preferably, based on step S110, in steps S120 and S130, regardless of whether the unwinding shaft is coaxial or non-coaxial, the unwinding shaft includes an independent unwinding roller corresponding to each roll of solid electrolyte membrane, so that each roll of solid electrolyte membrane is adjusted through step S110.

[0083] In one embodiment, the step of unwinding at least two rolls of solid electrolyte membrane and electrode sheet further includes: S140. At least two rolls of solid electrolyte membrane are unwound from both sides of the electrode sheet. After performing step S140, step S200 is performed to combine the solid electrolyte membrane and the electrode sheet, thereby obtaining a composite electrode sheet with solid electrolyte membrane on both sides of the electrode sheet.

[0084] Furthermore, the electrode sheet extends horizontally, and the two sides of the electrode sheet refer to the two sides facing away from each other in the vertical direction. In step S140, at least three rolls of solid electrolyte membrane are unwound, wherein at least two rolls of solid electrolyte membrane are located on the same side of the electrode sheet in the vertical direction, and at least one roll of solid electrolyte membrane is located on the other two sides of the electrode sheet facing away from each other in the vertical direction. Thus, a composite electrode sheet with solid electrolyte membrane on both sides of at least one roll of electrode sheet and a composite electrode sheet with solid electrolyte membrane on only one side can be obtained simultaneously, which can meet the needs of various composite electrode sheets. It is understood that step S140 can be executed simultaneously with steps S120 or S130.

[0085] In step S200, each roll of solid electrolyte membrane is laminated side-by-side onto the electrode sheet. Each roll of solid electrolyte membrane forms an electrolyte layer on the electrode sheet, and the orthographic projections of each solid electrolyte layer on the electrode sheet do not overlap. It is understood that at least two rolls of solid electrolyte membrane can be arranged parallel to each other or at an angle to each other. The process is performed by rolling, using a pair of matching pressure rollers to press the unwound electrode sheet and solid electrolyte membrane together as required to form a composite electrode sheet.

[0086] In one embodiment, step S200, which involves laminating each roll of solid electrolyte membrane onto the electrode sheet in parallel with each other, further includes: S210. Rolling each roll of solid electrolyte membrane onto the electrode sheet simultaneously.

[0087] Furthermore, the simultaneous roll-pressing of each roll of solid electrolyte membrane includes at least one of the following: simultaneous roll-pressing and roll-pressing under pressure rollers at the same position. When roll-pressing is performed under pressure rollers at the same position, the composite pressure rollers cover the entire electrode sheet pair, improving composite efficiency and ensuring the stability of the quality of each roll of composite electrode sheet. When roll-pressing is performed simultaneously, the composite pressure rollers simultaneously roll multiple pairs of rollers at different positions, either identical or different, improving electrode sheet composite efficiency and making the composite equipment more convenient to match the corresponding space requirements.

[0088] In one embodiment, step S200, which involves laminating each roll of solid electrolyte membrane onto the electrode sheet in parallel with each other, further includes: S220. Rolling each roll of solid electrolyte membrane onto the electrode sheet.

[0089] Furthermore, the simultaneous roll-pressing of each roll of solid electrolyte membrane includes at least one of the following: roll-pressing at different times and roll-pressing under pressure rollers at different positions. When roll-pressing is performed under pressure rollers at different positions, multiple pairs of rollers with different structures at different positions simultaneously perform the pressing, improving the efficiency of electrode lamination. Appropriate pairs of rollers can be configured according to the characteristics of different solid electrolyte membranes, making it easier to match the space occupied by the lamination equipment. When roll-pressing is performed at different times, the same pair of rollers or multiple pairs of rollers perform the pressing sequentially. Appropriate pressing processes can be configured according to the characteristics of different solid electrolyte membranes, improving the applicability of electrode lamination.

[0090] In one embodiment, the width of the electrode sheet is greater than the sum of the widths of each roll of solid electrolyte membrane. The portion of the electrode sheet width exceeding the sum of the widths of each roll of solid electrolyte membrane is distributed between each roll of solid electrolyte membrane, such that gaps are formed between each roll of solid electrolyte membrane when it is laminated onto the electrode sheet.

[0091] In some embodiments, S200 is followed by S300, in which the composite electrode is cut along the gap.

[0092] In step S300, a cutting assembly is set to cut the composite electrode sheet along the gap, with the cutter of the cutting assembly positioned parallel to the gap. Multiple rolls of composite electrode sheet are obtained, corresponding to the number of rolls of the solid electrolyte membrane.

[0093] In one embodiment, after step S300 of cutting the composite electrode along the gap, step S400 is included: winding up at least two rolls of base film and at least two rolls of composite electrode produced after the solid electrolyte membrane is laminated.

[0094] The solid electrolyte membrane comprises a solid electrolyte layer and a base film supporting the solid electrolyte layer. Step S200, the composite process, involves transferring the solid electrolyte layer from the base film to the electrode plate and bonding the solid electrolyte layer to the electrode plate. The number of rolls of the base film corresponds to the number of rolls of the solid electrolyte membrane.

[0095] Furthermore, in step S400, the cut composite electrode sheets are wound up in directions parallel to the electrode sheets, with each roll of base film being wound up alternately with the composite electrode sheet. Furthermore, in at least one of the horizontal and vertical directions, the base film and composite electrode sheets are wound up around different position axes.

[0096] In one embodiment, step S400 of winding at least two rolls of base film and composite electrode further includes: S410. Each roll of base film and composite electrode is wound on a corresponding winding shaft, and the tension of each roll of base film is adjusted to a preset tension by adjusting the winding shaft, and / or the tension of the composite electrode is adjusted to a preset tension by adjusting the winding shaft.

[0097] Furthermore, the step of adjusting the take-up shaft also includes at least one of the following steps:

[0098] S411. Adjust the position of the unwinding shaft corresponding to each roll of base film and / or composite electrode to change the tension of each roll of base film and / or composite electrode to achieve the corresponding preset tension.

[0099] S412. Adjust the unwinding speed of the unwinding shaft corresponding to each roll of base film and / or composite electrode to change the tension of each roll of base film and / or composite electrode to achieve the corresponding preset tension.

[0100] S413. An adjustment mechanism is provided to change the tension of each roll of base film and / or composite electrode sheet after lamination and before winding, so that the tension of each roll of base film and / or composite electrode sheet reaches the corresponding preset tension.

[0101] In one embodiment, step S400 further includes: S420. Each roll of base film is wound on the same take-up shaft, and then the same take-up shaft is operated to take up each roll of base film.

[0102] It is understood that the aforementioned "same take-up roller" refers to each roll of base film being coaxially wound. Each roll of base film can be wound on the same take-up roller or on different take-up rollers arranged coaxially. When the base film is wound on different take-up rollers arranged coaxially, the different take-up rollers can be arranged continuously coaxially or spaced apart. Coaxial winding is particularly suitable when each roll of base film has the same material and width, and each roll of base film has the same characteristics, such as consistent tension. Coaxial winding can better tighten the base film.

[0103] In one embodiment, step S400 further includes: S430. Each roll of base film is wound on a corresponding take-up shaft, at least two of the take-up shafts are spaced apart from each other, and then the respective take-up shafts are operated to wind up each roll of base film.

[0104] It is understood that in step S430, a portion of the base film is wound on the same take-up roller, and another portion is wound on take-up rollers with different axes, or each roll of base film is wound on take-up rollers with different axes. The aforementioned spacing refers to at least two of the take-up rollers being located at different positions in the vertical or horizontal direction. Steps S420 and S430 are different schemes implemented in parallel. The non-coaxial, partially non-coaxial unwinding method is particularly suitable when there are differences in the material and width of each roll of base film. Due to the differences in width and material, each roll of base film has different characteristics, such as inconsistent tension. Using non-coaxial unwinding to match the corresponding characteristics of different rolls of base film is beneficial for tightening the corresponding base film according to its characteristics.

[0105] In one embodiment, corresponding to step S140, step S400 further includes: S440. At least two rolls of base film are wound up on opposite sides of the composite electrode. Further, step S440 includes at least three rolls of base film being wound up, wherein at least two rolls of base film are located on the same side of the electrode in the vertical direction, and at least one roll of base film is located on opposite sides of the composite electrode in the vertical direction. It is understood that step S440 can be performed simultaneously with steps S420 or S430.

[0106] Combination Figure 2 , Figure 3 As shown, Figure 2 , Figure 3A schematic diagram of the structure of a composite electrode preparation apparatus 1 according to an embodiment of this application is shown. The preparation apparatus 1 includes an unwinding shaft 10, a winding shaft 30, and a composite assembly 20. Optionally, the preparation apparatus 1 prepares the composite electrode 4 using the preparation method described above.

[0107] The unwinding shaft 10 includes a first unwinding roller 11 for winding at least two rolls of solid electrolyte membrane 3 and a second unwinding roller 12 for winding electrode sheets 2. The first unwinding roller 11 unwinds each roll of solid electrolyte membrane according to a corresponding preset tension. The take-up shaft 30 includes a first take-up roller 31 for winding at least two rolls of base film 5 and a second take-up roller 32 for winding composite electrode sheets 4. The take-up shaft can take up each roll of base film and composite electrode sheet according to a corresponding preset tension. A composite assembly 20 is disposed between the unwinding shaft 10 and the take-up shaft 30. The composite assembly 20 is used to composite at least two rolls of solid electrolyte membrane 3 and electrode sheets 2 to form a composite electrode sheet 4. Each roll of the solid electrolyte membrane 3 is composited side by side on the electrode sheet 2, and there is a gap between adjacent solid electrolyte membranes 3 on the composite electrode sheet 4.

[0108] Optionally, the preparation device 1 also includes a frame, which is connected to the unwinding shaft 10, the winding shaft 30 and the composite component 20 respectively, for supporting the unwinding shaft 10, the winding shaft 30 and the composite component 20 in the corresponding positions.

[0109] In one embodiment, the unwinding shaft 10 is an adjustable tension structure to unwind the solid electrolyte membrane according to a preset tension. Further, the unwinding shaft 10 is a slip-ring shaft or a separate air-expanding shaft. It is understood that the winding shaft 30 is an adjustable tension structure to wind the base film or composite electrode sheet according to a preset tension. Further, the winding shaft 30 is a slip-ring shaft or a separate air-expanding shaft. The following description uses the unwinding shaft 10 as an example.

[0110] like Figure 4 As shown, the differential shaft 13 includes a main shaft 131 and multiple differential rings 132 disposed on the main shaft 131. When the differential shaft 13 is working, the differential rings are controlled by 132 to slip with a certain slip torque. The amount of slippage can compensate for the speed difference generated, thereby accurately controlling the tension of each roll of solid electrolyte membrane disposed on it, ensuring that each roll of solid electrolyte membrane is independently controlled according to requirements.

[0111] like Figure 5The described detachable air-expanding shaft 14 includes a shaft body 141, which has a hollow structure. The shaft body 141 has multiple through holes communicating with the cavity, and elastic elements 142 are detachably connected to the shaft body 141 at each through hole. When the detachable air-expanding shaft 14 is working, the elastic elements 142 are controlled to expand and inflate, tightening the wound solid electrolyte membrane. The tension of the solid electrolyte membrane is changed by varying the volume of the expansion. At least one air bladder is provided within the cavity, connected to the elastic elements 142 either together or separately. The volume change of the elastic element 142 is controlled by the change in the gas volume within the air bladder. Preferably, each elastic element 142 has an independent air bladder, and the air bladder can also be separated when the elastic element 142 is disassembled. This allows for adjustment of the tension of the detachable air-expanding shaft 14 at different orientations and positions to suit the characteristics of different solid electrolyte membranes. Furthermore, the elastic elements 142 can be disassembled and replaced, extending their service life.

[0112] In one embodiment, the preparation apparatus 1 further includes an adjustment component that can adjust the position and rotation speed of the unwinding shaft 10 to adjust the tension of the solid electrolyte membrane during unwinding; and / or, the adjustment component can adjust the position and rotation speed of the winding shaft 30 to adjust the tension of the base film or composite electrode sheet during winding.

[0113] In one embodiment, an adjustment shaft is provided between the unwinding shaft 10 and the composite assembly 20. A solid electrolyte membrane extending from the unwinding shaft 10 abuts against the adjustment shaft, which can be adjusted to regulate the tension of the solid electrolyte membrane. And / or, an adjustment shaft is provided between the take-up shaft 30 and the composite assembly 20. A base film and / or composite electrode extending from the composite assembly 20 abuts against the adjustment shaft, which can be adjusted to regulate the tension of the base film and / or composite electrode. Specifically, the adjustment of the adjustment shaft includes vertical and horizontal position adjustment, as well as rotational speed adjustment.

[0114] In one embodiment, the first unwinding roller 11 is provided with different rolls of solid electrolyte membrane 3 wound around the first unwinding roller 11 at intervals, as shown in the figure.

[0115] In one embodiment, there are multiple first unwinding rollers 11, and different rolls of solid electrolyte membrane 3 are respectively wound on the corresponding first unwinding rollers 11, and at least two of the multiple first unwinding rollers 11 are coaxially arranged.

[0116] In one embodiment, there are multiple first unwinding rollers 11, and different rolls of solid electrolyte membrane 3 are respectively wound on the corresponding first unwinding rollers 11. At least two of the multiple first unwinding rollers 11 are non-coaxial, that is, in the vertical or horizontal direction, at least two of the multiple first unwinding rollers 11 are located at different positions.

[0117] In one embodiment, a first take-up roller 31 is provided with different roll base films 5 wound around the first take-up roller 31 at intervals.

[0118] In one embodiment, there are multiple first take-up rollers 31, and different roll base films 5 are respectively wound on the corresponding first take-up rollers 31, and at least two of the multiple first take-up rollers 31 are coaxially arranged.

[0119] In one embodiment, there are multiple first take-up rollers 31, and different roll base films 5 are respectively wound on the corresponding first take-up rollers 31. At least two of the multiple first take-up rollers 31 are non-coaxial, that is, in the vertical or horizontal direction, at least two of the multiple first take-up rollers 31 are located at different positions.

[0120] Furthermore, the electrode sheet 2 and the composite electrode sheet 4 extend in the same horizontal direction, that is, the second unwinding roller 12 and the second winding roller 32 are located at the same height in the vertical direction. Optionally, the first unwinding roller 11 and the first winding roller 31 are symmetrically arranged about the vertical plane in which the composite assembly 20 is located. The second unwinding roller 12 and the second winding roller 32 are symmetrically arranged about the vertical plane in which the composite assembly 20 is located.

[0121] The composite component 20 includes a first pressure roller 21 and a second pressure roller 22 disposed opposite to each other, with a solid electrolyte membrane 3 and an electrode sheet 2 passing between the first pressure roller 21 and the second pressure roller 22 to form a composite electrode sheet 4.

[0122] In some embodiments, the widths of the first pressure roller 21 and the second pressure roller 22 are the same, and both are greater than or equal to the width of the electrode sheet 2, so as to achieve simultaneous rolling of the solid electrolyte membrane 3 and the electrode sheet 2.

[0123] In some embodiments, the first pressure roller 21 and the second pressure roller 22 are provided in multiple groups, each group including a first pressure roller 21 and a second pressure roller 22 with the same width. The width of each group of pressure rollers is greater than or equal to the width of the corresponding roll of solid electrolyte membrane 3, so as to realize the rolling of solid electrolyte membrane 3 and electrode plate 2 at different times or simultaneously.

[0124] In some embodiments, a plurality of first pressure rollers 21 are provided, and a single second pressure roller 22 is provided. The width of the plurality of first pressure rollers 21 is greater than or equal to the width of the corresponding roll of solid electrolyte membrane 3, and the width of the second pressure roller 22 is greater than or equal to the width of the electrode sheet 2, so as to achieve rolling of the solid electrolyte membrane 3 and the electrode sheet 2 at different times or simultaneously.

[0125] Furthermore, the surfaces of the first pressure roller 21 and / or the second pressure roller 22 are made of an elastic material. Optionally, the pressure roller surfaces in the composite assembly 20 that contacts the solid electrolyte membrane 3 are made of an elastic material, i.e., elastic rollers, while the pressure roller surfaces in the composite assembly 20 that contacts the electrode plates 2 are made of a rigid material, i.e., rigid rollers. In some embodiments, the elastic rollers may be configured to surround and cover the rigid rollers with an elastic element.

[0126] When the situations described in steps S120 or S130 are involved, the surface of the first pressure roller 21 is made of an elastic material, and the surface of the second pressure roller 22 is made of a rigid material. When the situations described in step S140 are involved, the surfaces of both the first pressure roller 21 and the second pressure roller 22 are made of elastic materials. The elastic pressure rollers adjust the stress on the solid electrolyte membrane 3, so that the solid electrolyte membrane 3 after rolling can better cover the electrode sheet 2, and the thickness of the composite electrode sheet 4 tends to be uniform after rolling.

[0127] Optionally, the preparation apparatus 1 further includes a cutting assembly 40, located between the second take-up shaft 30 and the composite assembly 20. The cutting assembly 40 consists of two oppositely arranged cutting rollers and cutters positioned at corresponding positions on the outer periphery of the cutting rollers. The position of the cutters matches the gap position to be cut. The cutting assembly 40 cuts to obtain multi-roll composite electrode sheets 4 corresponding to the number of rolls of the solid electrolyte membrane 3.

[0128] Optionally, the cutting assembly 40 and the second take-up shaft 30 are located at the same height in the vertical direction. The first take-up shaft 30 and the cutting assembly 40 are spaced apart in the vertical direction.

[0129] This application also provides a lithium-ion battery, including a composite electrode prepared by the method described above, or including a composite electrode prepared using the apparatus described above.

[0130] The composite process in this application is carried out under dry conditions, which differs from traditional wet electrode preparation methods. Traditional wet composite electrode preparation involves first preparing a solid electrolyte slurry, then coating the solid electrolyte slurry onto the electrode sheet, or vice versa, preparing an electrode slurry and then coating the electrode slurry onto a solid electrolyte membrane. This application's preparation process does not use solvents, eliminating the cumbersome subsequent drying step and effectively reducing production costs.

[0131] It is understood that dry process refers to the preparation of related electrode sheets and electrolyte membranes without the addition of solvents; the technical solutions that may use trace amounts of liquid lubricants or other liquid additives during the rolling process should still be within the scope of protection of this application.

[0132] In some embodiments, both the electrode sheets and the solid electrolyte membrane are prepared by a dry process.

[0133] In some embodiments, at least one of the electrode sheet and the solid electrolyte membrane is prepared by a dry process.

[0134] In some embodiments, both the electrode sheets and the solid electrolyte membrane are prepared by a wet process.

[0135] It is understandable that electrode sheets and solid electrolyte membranes are preferably prepared under dry conditions, so that solvents are no longer needed in the entire electrode preparation process.

[0136] It is understandable that the preparation process of the electrode sheet and the solid electrolyte membrane is independent of the preparation process of the composite electrode. That is, if the wet process is used, the electrode sheet goes through the processes of coating, drying and rolling.

[0137] In some embodiments, the electrode sheet is a positive electrode sheet. Positive electrode materials, especially high-nickel ternary materials with high energy density, are prone to undesirable side reactions with electrolytes, especially non-aqueous electrolytes. These side reactions cause a decrease in battery performance and create potential safety hazards. Composite solid electrolyte layers on the surface of the positive electrode are beneficial to improving battery safety.

[0138] The positive electrode sheet comprises an active material layer and a current collector layer. In the dry preparation of the positive electrode sheet, the active material, conductive agent, and binder are first stirred to obtain a positive electrode mixture; this mixture is then subjected to fibrous treatment to obtain a fibrous mixture of the positive electrode; the fibrous mixture of the positive electrode and the current collector layer are then combined by roll forming to obtain the positive electrode sheet. In some embodiments, the fibrousization methods include, but are not limited to, air jet milling, high-speed stirring, mechanical fusion, and twin-screw extrusion.

[0139] The positive electrode active material layer is formed of a positive electrode active material containing one or more transition metal cations, such as manganese (Mn), nickel (Ni), cobalt (Co), chromium (Cr), iron (Fe), vanadium (V), and combinations thereof. The positive electrode active material layer has a thickness greater than or equal to about 1 μm and less than or equal to about 1,000 μm.

[0140] The positive electrode active material is one of layered oxides, spinel, and polyanionic materials. For example, layered oxides (e.g., rock salt layered oxides) comprise one or more lithium-based positive electrode active materials selected from: LiCoO2 (LCO), LiNixMnyCo1-x-yO2 (where 0≤x≤1 and 0≤y≤1), LiNi1-x-yCoxAlyO2 (where 0≤x≤1 and 0≤y≤1), LiNixMn1-xO2 (where 0≤x≤1), and Li1+xMO2 (where M is one of Mn, Ni, Co, and Al and 0≤x≤1). Spinel comprises one or more lithium-based positive electrode active materials selected from: LiMn2O4 (LMO) and LiNixMn1.5O4. Olivine-type materials comprise one or more lithium-based positive electrode active materials, LiMPO4 (where M is at least one of Fe, Ni, Co, and Mn). Polyanionic cations include, for example, phosphates such as LiV2(PO4)3 and / or silicates such as LiFeSiO4.

[0141] In some embodiments, one or more lithium-based cathode active materials may optionally be coated (e.g., by LiNbO3 and / or Al2O3) and / or may be doped (e.g., by magnesium (Mg)). Furthermore, in some embodiments, one or more lithium-based cathode active materials may optionally be mixed with one or more conductive materials that provide electronic conduction pathways and / or at least one polymeric binder material that improves the structural integrity of the cathode. For example, the cathode active material layer may comprise more than or equal to about 30% by weight and less than or equal to about 99% by weight of one or more lithium-based cathode active materials; more than or equal to about 0% by weight and less than or equal to about 30% by weight of conductive materials; and more than or equal to about 0% by weight and less than or equal to about 20% by weight of binder.

[0142] In some embodiments, the adhesive includes polytetrafluoroethylene (PTFE), sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), nitrile rubber (NBR), styrene-ethylene-butene-styrene copolymer (SEBS), styrene-butadiene-styrene copolymer (SBS), lithium polyacrylate (LiPAA), sodium polyacrylate (NaPAA), sodium alginate, lithium alginate, and combinations thereof.

[0143] In some embodiments, the conductive material may include carbon-based materials, powdered nickel or other metal particles, or conductive polymers. Carbon-based materials may include particles such as carbon black, graphite, acetylene black (e.g., KETCHENTM black or DENKATM black), carbon fibers and nanotubes, graphene, etc. Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, polypyrrole, etc.

[0144] It is understood that the examples of positive electrode active materials, binders, and conductive materials mentioned above are merely illustrative. Without departing from the inventive concept of this application, any known positive electrode active material, binder, or conductive material can be used in this application. Furthermore, the addition of known additives based on actual usage requirements should also be considered within the scope of protection of this application.

[0145] In some implementations, the current collector layer contains active material layers on both sides.

[0146] In some implementations, the current collector layer may be a metal foil or a composite current collector. For example, the metal foil may be aluminum foil.

[0147] The composite current collector may include a polymer base material and a metal layer formed on at least one surface of the polymer base film.

[0148] Studies have shown that traditional wet coating techniques often employ a water-based method. However, because the positive electrode active slurry is water-based, protrusions often form at the edges of the active material layer during the drying process due to the slurry's fluidity and surface tension. Furthermore, during rolling, these protrusions can directly cause cracks at the edges of the active material layer due to the rolling stress, ultimately leading to cracking of the positive electrode active material layer and affecting battery performance. Additionally, wet coating may also lead to problems such as expansion and rapid performance degradation during long-term battery cycling due to excessively high moisture content.

[0149] In some implementations, the electrode is a negative electrode.

[0150] The negative electrode sheet is formed from a lithium host material (e.g., a negative electrode active material) capable of being used as the negative terminal of a lithium-ion battery. In various aspects, the negative electrode sheet may be defined by a variety of negative electrode active material particles. Such negative electrode active material particles may be disposed in one or more layers to define the three-dimensional structure of the negative electrode. In some embodiments, the negative electrode may also include an electrolyte 50, such as a variety of electrolyte particles (not shown).

[0151] In some embodiments, the negative electrode may be a lithium-based negative electrode active material, which contains, for example, lithium metal and / or lithium alloys.

[0152] The negative electrode can be a silicon-based negative electrode active material, which includes, for example, silicon alloys, silicon oxide, or combinations thereof, and in some cases, it can also be mixed with graphite.

[0153] The negative electrode can be a carbon-based negative electrode active material, which includes one or more of graphite, graphene, carbon nanotubes (CNTs), and combinations thereof.

[0154] The negative electrode may also include one or more negative electrode active materials that accept lithium, such as lithium titanium oxide (Li4Ti5O12), one or more transition metals (e.g., tin (Sn)), one or more metal oxides (e.g., vanadium oxide (V2O5), tin oxide (SnO), titanium dioxide (TiO2)), titanium niobium oxide (TixNbyOz, where 0≤x≤2, 0≤y≤24 and 0≤z≤64), metal alloys (e.g., copper-tin alloy (Cu6Sn5)), and one or more metal sulfides (e.g., iron sulfide (FeS)).

[0155] Alternatively, the negative electrode active material in the negative electrode sheet may be doped with one or more conductive materials that provide an electron conduction path and / or at least one polymer binder material that improves the structural integrity of the negative electrode. For example, the negative electrode active material may be doped with binders such as: poly(tetrafluoroethylene) (PTFE), sodium carboxymethyl cellulose (CMC), styrene-butadiene rubber (SBR), polyvinylidene fluoride (PVDF), nitrile rubber (NBR), styrene-butadiene-styrene copolymer (SEBS), styrene-butadiene-styrene copolymer (SBS), lithium polyacrylate (LiPAA), sodium polyacrylate (NaPAA), sodium alginate, lithium alginate, and combinations thereof. The conductive material may include carbon-based materials, powdered nickel or other metal particles, or conductive polymers. Carbon-based materials may include particles such as carbon black, graphite, superP, acetylene black (e.g., KETCHENTM black or DENKATM black), carbon fibers and nanotubes, graphene, etc. Examples of conductive polymers include polyaniline, polythiophene, polyacetylene, polypyrrole, poly(3,4-ethylenedioxythiophene)polysulfonated styrene, etc.

[0156] The negative electrode may include more than or equal to about 50% by weight and less than or equal to about 99% by weight of negative electrode active material, optionally more than or equal to about 0% by weight and less than or equal to about 60% by weight of solid electrolyte, optionally more than or equal to about 0% by weight and less than or equal to about 15% by weight of conductive material, and optionally more than or equal to about 0% by weight and less than or equal to about 10% by weight of binder.

[0157] The embodiments of the present invention will be described in more detail below through examples. However, the embodiments of the present invention are not limited to these examples.

[0158] Example 1

[0159] 1. Preparation of positive electrode sheet

[0160] Lithium nickel cobalt manganese oxide was selected as the positive electrode active material, graphite as the conductive agent, and PTFE as the binder. The above substances were stirred at high speed to obtain a positive electrode mixture. Then, the mixture was subjected to a fibrous treatment using an air jet mill to obtain a fibrous mixture for the positive electrode. The fibrous mixture was then rolled to obtain a positive electrode active material layer. The positive electrode active material layer and a current collector were then rolled together to obtain the positive electrode sheet.

[0161] 2. Preparation of solid electrolyte membranes

[0162] LLZO was selected as the solid electrolyte, PTFE as the binder, and lithium bis(trifluoromethanesulfonylimide) as the lithium salt. The above substances were stirred at high speed to obtain a solid electrolyte mixture. Then, the mixture was subjected to fiberization treatment by air jet milling to obtain a fiberized solid electrolyte mixture. The fiberized solid electrolyte mixture was then rolled to obtain a solid electrolyte membrane.

[0163] 3. Preparation of composite positive electrode sheets

[0164] use Figure 6 , Figure 7 The fabrication apparatus 1a shown composites two rolls of solid electrolyte membrane located on the same side of the positive electrode 2a onto the positive electrode 2a. Furthermore, the solid electrolyte membrane includes a first solid electrolyte membrane 3a and a second solid electrolyte membrane 3b, both of which are made of the same material and have the same width.

[0165] The first solid electrolyte membrane 3a and the second solid electrolyte membrane 3b are unwound under a preset tension by two first unwinding rollers 111 positioned differently in the vertical direction. The first solid electrolyte membrane 3a and the second solid electrolyte membrane 3b are simultaneously laminated onto the electrode sheet 2a by the composite assembly 201 to obtain a composite electrode sheet. Figure 8 As shown, the composite electrode consists of a positive electrode 2a and a first solid electrolyte layer 7a and a second electrolyte layer 7b arranged side by side on the positive electrode 2a.

[0166] After the first solid electrolyte membrane 3a and the second solid electrolyte membrane 3b are combined, a first base membrane 5a and a second base membrane 5b are generated respectively. The first base membrane 5a and the second base membrane 5b are respectively wound up by two first take-up rollers 311 that are located at different positions in the vertical direction Y.

[0167] In the horizontal direction X, a cutting component 401 is provided on the side of the first take-up roller 311 away from the composite component 401. The cutting component cuts a composite electrode sheet along the gap 6a into a first composite electrode sheet 4a and a second composite electrode sheet 4b. The first composite electrode sheet 4a and the second composite electrode sheet 4b are respectively wound up by two second take-up rollers 321 that are located at different positions in the vertical direction Y.

[0168] It is understandable that the positions of the first unwinding roller 111, the first winding roller 311, and the second winding roller 321 are matched with each other.

[0169] The prepared composite electrode has no cracks on its surface and has a uniform thickness. The thickness of the first composite electrode 4a and the second composite electrode 4b is 150 μm, respectively.

[0170] Example 2

[0171] In this embodiment, the steps for preparing the positive electrode sheet and the solid electrolyte membrane are the same as in Example 1. The specific difference lies in the steps for preparing the composite positive electrode sheet, as detailed below.

[0172] use Figure 9 , Figure 10 The preparation apparatus 1b shown unwinds four rolls of solid electrolyte membrane, with each group consisting of two rolls of solid electrolyte membrane, including a first group of solid electrolyte membrane 3c and a second group of solid electrolyte membrane 3d. The two rolls of solid electrolyte membrane in each group are unwound on the same side of the positive electrode 2b, and the solid electrolyte membranes from different groups are located on opposite sides of the positive electrode 2b in the vertical direction.

[0173] Four rolls of the first solid electrolyte membrane 3c and the second solid electrolyte membrane 3d are simultaneously laminated onto the positive electrode 2b. Furthermore, the four rolls of solid electrolyte membrane are made of the same material and have the same width.

[0174] The four rolls of the first group of solid electrolyte membranes 3c and the second group of solid electrolyte membranes 3d are unwound under a preset tension by four first unwinding rollers 112 positioned at different locations in the vertical direction Y. Both the first group of solid electrolyte membranes 3c and the second group of solid electrolyte membranes 3d include a roll close to the positive electrode 2b, and these two rolls are positioned closer to the composite assembly 202 in the horizontal direction X compared to the other two rolls. The first group of solid electrolyte membranes 3c and the second group of solid electrolyte membranes 3d are simultaneously laminated onto the positive electrode 2b by the composite assembly 202 to obtain a composite electrode. Figure 11 As shown, the composite electrode consists of a positive electrode 2b and a first solid electrolyte layer 7c and a second electrolyte layer 7d arranged side by side on the positive electrode 2b.

[0175] After the first group of solid electrolyte membranes 3c and the second group of solid electrolyte membranes 3d are combined, a first group of base membranes 5c and a second group of base membranes 5d are generated, respectively. The first group of base membranes 5c and the second group of base membranes 5d are respectively wound up by two sets of first take-up rollers 312 at different positions in the vertical direction Y. Optionally, the first take-up rollers 312 and the first unwind rollers 112 are symmetrical with respect to the vertical plane passing through the axis of the composite component.

[0176] In the horizontal direction, a cutting component 402 is provided on the side of the first take-up roller 312 away from the composite assembly 202. The cutting component 402 cuts a composite electrode sheet along the gap 6b into a first composite electrode sheet 4c and a second composite electrode sheet 4d. The first composite electrode sheet 4c and the second composite electrode sheet 4d are respectively wound up by a second take-up roller 322.

[0177] The prepared composite electrode has no cracks on its surface and has a uniform thickness. The thicknesses of the first composite electrode 4c and the second composite electrode 4d are 166 μm, respectively.

[0178] Example 3

[0179] In this embodiment, step 1 of preparing the positive electrode sheet is the same as in Example 1. The specific difference lies in the steps of preparing the solid electrolyte membrane and preparing the composite positive electrode sheet, as detailed below.

[0180] 2. Preparation of two solid electrolyte membranes made of different materials

[0181] LLZO was selected as the solid electrolyte, PTFE as the binder, and lithium bis(trifluoromethanesulfonylimide) as the lithium salt. The above substances were stirred at high speed to obtain a solid electrolyte mixture. Then, the mixture was subjected to fiberization treatment by air jet milling to obtain a fiberized solid electrolyte mixture. The fiberized solid electrolyte mixture was then rolled to obtain a solid electrolyte membrane of the first material.

[0182] Perovskite ceramic was selected as the solid electrolyte, PTFE as the binder, and lithium bis(trifluoromethanesulfonylimide) as the lithium salt. The above substances were stirred at high speed to obtain a solid electrolyte mixture. Then, the mixture was subjected to fiberization treatment by air jet milling to obtain a fiberized solid electrolyte mixture. The fiberized solid electrolyte mixture was then rolled to obtain a solid electrolyte membrane of the second material.

[0183] 3. Preparation of composite positive electrode sheets

[0184] use Figure 12 , Figure 13 The preparation apparatus 1c shown unwinds four rolls of solid electrolyte membrane under a preset tension. Each group consists of two rolls of solid electrolyte membrane, including a first group of solid electrolyte membrane 3e and a second group of solid electrolyte membrane 3f. The two rolls of solid electrolyte membrane in each group are unwound on the same side of the electrode sheet, and the solid electrolyte membranes from different groups are located on opposite sides of the positive electrode sheet 2c in the vertical direction.

[0185] Four rolls of the first group of solid electrolyte membranes 3e and the second group of solid electrolyte membranes 3f are simultaneously laminated onto the positive electrode 2c. Furthermore, the first group of solid electrolyte membranes 3e and the second group of solid electrolyte membranes 3f are made of different materials but have the same width. The first group of solid electrolyte membranes 3e is made of a first material, and the second group of solid electrolyte membranes 3f is made of a second material. Each roll of the first group of solid electrolyte membranes 3e and the second group of solid electrolyte membranes 3f is made of the same material.

[0186] Two rolls of the first group of solid electrolyte membranes 3e are unwound by a first unwinding roller positioned vertically at the same level, and two rolls of the second group of solid electrolyte membranes 3f are each unwound by a first unwinding roller positioned vertically at the same level. Optionally, the two rolls of the first group of solid electrolyte membranes 3e and the two rolls of the second group of solid electrolyte membranes 3f are unwound symmetrically with respect to the positive electrode 2c. The first group of solid electrolyte membranes 3e and the second group of solid electrolyte membranes 3f are simultaneously laminated onto the positive electrode 2c by the composite assembly 203 to obtain a composite electrode. Figure 14 As shown, the composite electrode consists of a positive electrode 2c and a first solid electrolyte layer 7e and a second electrolyte layer 7f located side by side on the positive electrode 2c.

[0187] After the first group of solid electrolyte membranes 3e and the second group of solid electrolyte membranes 3f are combined, a first group of base membranes 5e and a second group of base membranes 5f are generated respectively. The first group of base membranes 5e and the second group of base membranes 5f are wound up by a first take-up roller 313 that is positioned at the same position in the vertical direction Y. The second group of base membranes 5f is also wound up by the first take-up roller 313 that is positioned at the same position in the vertical direction. Optionally, the first take-up roller 313 and the first unwind roller 113 are symmetrical with respect to a vertical plane passing through the axis of the composite assembly 203.

[0188] In the horizontal direction X, a cutting component 403 is provided on the side of the first take-up roller 113 away from the composite component 203. The cutting component 403 cuts a composite electrode sheet along the gap 6c into a first composite electrode sheet 4e and a second composite electrode sheet 4f. The first composite electrode sheet 4e and the second composite electrode sheet 4f are respectively wound up by a second take-up roller 323.

[0189] The prepared composite electrode has no cracks on its surface and has a uniform thickness. The thicknesses of the first composite electrode 4e and the second composite electrode 4f are 170 μm, respectively.

[0190] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0191] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a composite electrode, characterized in that, Including the following steps: At least two rolls of solid electrolyte membrane are unwound according to the corresponding preset tension, and the electrode sheets are also unwound. Each roll of the solid electrolyte membrane is laminated side by side onto the electrode sheet to obtain a composite electrode sheet; there are gaps between adjacent solid electrolyte membranes on the composite electrode sheet; The composite electrode is cut along the gap.

2. The method for preparing the composite electrode according to claim 1, characterized in that, The step of unwinding at least two rolls of solid electrolyte membrane at a preset tension for each roll includes: each roll of the solid electrolyte membrane is wound on a corresponding unwinding shaft, and the tension of each roll of the solid electrolyte membrane is adjusted to reach the preset tension by adjusting the unwinding shaft.

3. The method for preparing the composite electrode according to claim 1, characterized in that, The step of unwinding at least two rolls of solid electrolyte membrane at corresponding preset tensions further includes: each roll of solid electrolyte membrane being wound on the same unwinding shaft; or, each roll of solid electrolyte membrane being wound on a corresponding unwinding shaft, wherein at least two of the unwinding shafts are spaced apart from each other.

4. The method for preparing the composite electrode according to claim 1, characterized in that, After the step of cutting the composite electrode along the gap, the step of: winding up the base film and the composite electrode generated after the solid electrolyte membrane is composited, with each roll of the base film corresponding to each roll of the solid electrolyte membrane; Each roll of the base film is wound on the same take-up spool; or, each roll of the film is wound on a corresponding take-up spool, with at least two of the take-up spools spaced apart from each other.

5. An apparatus for preparing composite electrodes, applied to the preparation method as described in any one of claims 1-4, characterized in that, The preparation apparatus includes: The unwinding roller includes a first unwinding roller for winding at least two rolls of solid electrolyte membrane and a second unwinding roller for winding electrode sheets; the first unwinding roller unwinds each roll of solid electrolyte membrane according to a corresponding preset tension. The take-up shaft includes a first take-up roller for winding at least two rolls of base film and a second take-up roller for winding composite electrode sheets; A composite assembly is disposed between the unwinding shaft and the take-up shaft. The composite assembly is used to combine at least two rolls of the solid electrolyte membrane and the electrode sheet with a preset tension to form the composite electrode sheet. In this embodiment, each roll of the solid electrolyte membrane is laminated side by side on the electrode sheet, and there is a gap between adjacent solid electrolyte membranes on the composite electrode sheet.

6. The apparatus for preparing composite electrodes according to claim 5, characterized in that, The unwinding shaft is a slip shaft or a split-type air-expansion shaft.

7. The apparatus for preparing composite electrodes according to claim 5, characterized in that, The preparation apparatus further includes an adjustment component, which can adjust the unwinding shaft to adjust the tension of the solid electrolyte membrane during unwinding.

8. The apparatus for preparing composite electrodes according to claim 5, characterized in that, An adjustment shaft is provided between the unwinding shaft and the composite component, and the solid electrolyte membrane extending from the unwinding shaft abuts against the adjustment shaft. The adjustment shaft can be adjusted to adjust the tension of the solid electrolyte membrane. And / or, an adjustment shaft is provided between the take-up shaft and the composite assembly, the base film extending from the composite assembly and / or the composite electrode abutting against the adjustment shaft, the adjustment shaft being adjustable to adjust the tension of the base film and / or the composite electrode.

9. The apparatus for preparing composite electrodes according to claim 5, characterized in that, The composite component includes a first pressure roller and a second pressure roller disposed opposite to each other, the solid electrolyte membrane and the electrode sheet passing between the first pressure roller and the second pressure roller to form the composite electrode sheet; the surfaces of the first pressure roller and / or the second pressure roller are made of an elastic material.

10. A lithium-ion battery comprising a composite electrode prepared by the method according to any one of claims 1 to 4.

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