Method for assembling all-solid-state battery and all-solid-state battery

Abstract

The application discloses an assembling method of a full solid-state battery and the full solid-state battery, and belongs to the technical field of new energy batteries. The assembling method comprises the following steps: taking a continuous negative electrode composite electrode roll as a carrier, and adhering a positive electrode composite electrode sheet to the carrier; dispensing and solidifying along the periphery of the positive electrode composite electrode sheet to form a coating frame; cutting the coating frame along the outer contour to obtain an electrode unit; stacking a plurality of electrode units to form a roll core, and covering the negative electrode composite electrode sheet on the outermost side. The negative electrode composite electrode roll and the positive electrode composite electrode sheet are prepared by using a roll-to-roll continuous composite process, and the continuous negative electrode composite electrode roll is taken as the carrier for adhesion and stacking, so that the process of single sheet stacking is reduced, and the assembling efficiency is improved. Through the coating frame technology, the adhesion between the coating frame and the electrode sheet is closer, the assembly tolerance problem of the prefabricated frame is avoided, and the reliability and process flexibility of the battery core are improved. The application also provides the full solid-state battery prepared by the above method, and the full solid-state battery has excellent electrochemical performance and manufacturing consistency.

Description

Technical Field

[0001] This invention belongs to the field of new energy battery technology, specifically, it relates to an assembly method of a sulfide all-solid-state battery and the all-solid-state battery obtained by the method. Background Technology

[0002] Solid-state batteries have become a research hotspot in the field of new energy batteries due to their high energy density and high safety. Among them, sulfide electrolytes have excellent ionic conductivity, making sulfide all-solid-state batteries particularly noteworthy.

[0003] Currently, numerous patents disclose powder materials and preparation methods for various functional layers in sulfide-based all-solid-state batteries. However, patent technologies on how to efficiently and reliably assemble the functional layers (positive electrode, negative electrode, and electrolyte layer) into a single cell are relatively few. In existing technologies, the assembly of all-solid-state batteries often employs Z-shaped stacking or thermoforming, typically requiring prefabricated insulating frames (such as polymer or metal frames) to isolate the positive and negative electrodes and provide encapsulation boundaries. For example, patent (application number 202411744244.0) discloses a method for manufacturing solid-state battery cells based on single-sided adhesive frame molding. This method requires fabricating an adhesive frame on one electrode and embedding another electrode, involving numerous steps and the preparation of multiple sheet-like functional layers for alternating stacking, resulting in low stacking efficiency. Furthermore, insufficient adhesion between the prefabricated frame and the electrode can easily lead to interlayer slippage during high-pressure compaction of the all-solid-state battery, affecting battery performance.

[0004] The patent (application number 202511805351.4) provides a cell structure installed by rotating and stacking, but the adhesive strip formed during the coating stage may not be effectively protected during the isostatic pressing process. Furthermore, none of these solutions fundamentally achieve efficient and reliable integrated assembly.

[0005] Therefore, developing an all-solid-state battery assembly method that can reduce process steps, improve assembly efficiency and cell reliability is of great significance for promoting the industrialization of sulfide all-solid-state batteries. Summary of the Invention

[0006] In view of the above problems, the technical problem to be solved by the present invention is to overcome the defects of low stacking efficiency and poor adaptability of prefabricated frame in the existing all-solid-state battery assembly process, and to provide an efficient, reliable and flexible all-solid-state battery assembly method and an all-solid-state battery.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: On one hand, this invention proposes an assembly method for an all-solid-state battery, comprising the following process steps: S1: Provide a continuous negative composite electrode roll as a carrier, transfer the pre-made positive composite electrode sheet and attach it to the surface of the negative composite electrode roll at a predetermined interval; S2: Apply adhesive around each of the positive electrode composite sheets, and after curing, form an adhesive frame surrounding the positive electrode composite sheet. S3: Die-cut along the outer contour of the glue-coating frame according to a fixed outer contour size to obtain an electrode unit containing a positive composite electrode sheet, a glue-coating frame and a lower part of the negative composite electrode roll; S4: Stack multiple electrode units to obtain a stack, and cover the top layer of the stack with a negative electrode composite unit to form a battery core; The negative electrode composite unit is a segment die-cut from the negative electrode composite electrode roll, and its die-cutting size is the same as the outer contour size used to die-cut the electrode unit in step S3.

[0008] Furthermore, in step S1, the transfer is performed via a vacuum suction cup (such as...). Figure 7 ) or a continuous turnover belt with vacuum suction holes (such as Figure 9 The bonding is achieved by flat plate pressing or round roller pressing. Under certain parameters (temperature, speed, pressure and time, etc.), the positive electrode composite sheet and the negative electrode composite sheet are further bonded to prevent the sheet from falling off during movement. And / or, each positive electrode composite sheet transferred needs to be spaced by a certain size, with a spacing of ≥5mm, to achieve better dispensing and die-cutting effects.

[0009] Furthermore, in step S2, the adhesive is a UV-curable adhesive, which is applied by a dispensing machine and cured by ultraviolet light to form the coated frame. The dispensing and UV curing process involves injecting a UV adhesive of a certain viscosity into a frame-shaped structure of a certain width and thickness along the outer dimensions of the positive electrode composite sheet using a high-precision dispensing machine under set parameters (injection volume, speed, trajectory, etc.), and then cross-linking and curing it under ultraviolet light irradiation under set parameters (wavelength, power, time, etc.).

[0010] Furthermore, in step S1, the method for preparing the negative electrode composite roll is as follows: under set parameters (pressure, roll gap, temperature, etc.), two layers of sulfide solid electrolyte membrane are rolled and laminated on both sides of a negative electrode functional roll in a roll-to-roll manner, and then wound up for later use or for immediate use; the method for preparing the positive electrode composite sheet is as follows: under set parameters (pressure, roll gap, temperature, etc.), two layers of positive electrode film are rolled and laminated on both sides of a carbon-coated aluminum foil in a roll-to-roll manner to form a positive electrode composite roll, and then die-cut and punched into sheets, with pre-reserved tab positions.

[0011] Furthermore, the negative electrode functional roll is a composite material roll with a metal or metal oxide functional layer formed on both sides of a carbon-coated copper foil by thermal evaporation or magnetron sputtering; the thickness of the functional layer on one side is 0.2~10μm.

[0012] Furthermore, the copper foil of the carbon-coated copper foil has a thickness of 4-8 μm, and the carbon coating thickness on one side is 1-8 μm; the aluminum foil of the carbon-coated aluminum foil has a thickness of 9-16 μm, and the carbon coating thickness on one side is 1-8 μm; the UV-curable adhesive is a liquid mixture of a single-component or multi-component photocurable resin, a diluent, an initiator, and a functional filler, with a viscosity of 500-30000 CPS. The UV-curable adhesive is a conventional curing agent, and its composition is existing technology and is not limited here.

[0013] Furthermore, the height of the positive electrode film in the positive electrode composite electrode sheet is 0-2 mm smaller than the height of the sulfide solid electrolyte film in the negative electrode composite electrode sheet. The adhesive-coating frame has a frame-shaped structure. Its inner edge dimensions match the dimensions of the positive electrode film in the positive electrode composite sheet, and its outer edge dimensions are 1-5 mm larger than the inner edge dimensions. After curing, its thickness differs from the thickness of the positive electrode composite sheet by within ±100 μm. Specifically: (1) The total height of the carbon-coated copper foil is equal to the height of the carbon-coated area plus the blank height; (2) The total height of the carbon-coated aluminum foil is equal to the height of the carbon-coated area plus the blank height; (3) The height of the negative electrode functional roll is equal to the height of the carbon coating area of ​​the carbon-coated copper foil ± 0.5 mm, and its total height is equal to the height of the functional area + the height of the tab blank. (4) The height of the sulfide electrolyte membrane of the negative electrode composite roll is equal to the height of the functional area of ​​the negative electrode functional roll - (0~2) mm; (5) The positive electrode composite electrode A has a positive electrode film height = height of carbon coating area of ​​carbon-coated aluminum foil - (0~2) mm, a positive electrode film height = height of sulfide electrolyte film of negative electrode composite electrode roll - (0~2) mm, a total height = positive electrode film height + tab clearance height, and a positive electrode film width after cutting = width of carbon coating area of ​​carbon-coated aluminum foil. (6) The adhesive-coating frame is mainly a frame structure. Its inner dimension height = the height of the positive electrode film of the positive electrode composite sheet A ± 0.5 mm, its inner dimension width = the width of the positive electrode film of the positive electrode composite sheet A ± 0.5 mm, its outer dimension height = inner dimension height + (1~5) mm, its outer dimension width = inner dimension width + (1~5) mm, and its cured thickness = the thickness of the positive electrode composite sheet A ± 100 μm; (7) The height of the positive electrode tab is equal to or approximately equal to the height of the negative electrode tab, and the width of the positive electrode tab is equal to or approximately equal to the width of the negative electrode tab.

[0014] Furthermore, the method also includes: pre-coating or simultaneously forming a side coating layer with the pre-coated frame at the junction of the carbon-coated area of ​​the carbon-coated aluminum foil or carbon-coated copper foil and the blank area of ​​the tab; after pre-drying, UV curing is performed in the manner described above to protect the tab and prevent it from tearing. The material of the side coating layer is Al2O3, SiO2, or UV adhesive.

[0015] Furthermore, when transferring the positive composite electrode sheet to the negative composite electrode roll, a certain spacing is set between each electrode sheet. An integrated winding method can be used to achieve rapid assembly, reduce the number of die-cutting operations, and improve process efficiency.

[0016] Furthermore, an alternative is proposed: In step S2, the positive composite electrode sheet is replaced with positive composite electrode sheet B, and in step S1, the negative composite electrode roll is replaced with a negative functional electrode roll; the structure of the positive composite electrode sheet B is as follows: on both sides of the carbon-coated aluminum foil, a positive electrode film and a sulfide solid electrolyte film are sequentially rolled and laminated from the inside to the outside; the positive composite electrode sheet B is prepared by rolling and laminating two layers of sulfide solid electrolyte film on the outside and two layers of positive electrode film on the inside of the carbon-coated aluminum foil in a roll-to-roll manner under set parameters, and then die-cutting and punching it into a sheet according to the size of the positive composite electrode sheet B, leaving the tab position.

[0017] On the other hand, the present invention also proposes an all-solid-state battery, which is prepared by the assembly method described above. The all-solid-state battery includes an aluminum-plastic film encapsulation shell and a stacked cell located within the shell. The cell consists of multiple layers of positive electrode / electrolyte / negative electrode units separated and positioned by an in-situ cured adhesive frame.

[0018] Compared with the prior art, the present invention has the following significant advantages: (1) High-efficiency integrated assembly: Using continuous negative electrode composite rolls as carriers, continuous bonding, online encapsulation (i.e., gluing frame) and overall die-cutting of positive electrode sheets are realized, which greatly reduces the handling and alignment processes of individual components, reduces the diversity of single-piece components, reduces the steps of sequentially bonding multiple single-piece components, and reduces the mechanical damage to the electrode sheets that may be caused by multiple transfers. Roll-to-roll continuous bonding significantly improves the stacking efficiency and the automation level of the production line.

[0019] (2) Excellent interface contact and high reliability: The "instant glue frame" technology allows the glue frame to be directly coated and cured after the positive electrode sheet is in place, achieving "in-situ forming" and tight fit with the positive and negative electrode components, eliminating the assembly tolerance caused by the prefabricated frame, and improving the sealing and insulation properties, thus reducing the risk of short circuit.

[0020] (3) Good process flexibility: The size and thickness of the frame can be easily adjusted through the dispensing process. There is no need to customize pre-made frame molds for different battery models, which reduces the complexity of replacing pre-made frames due to modification, reduces modification costs and time, adapts to the production needs of small batches and multiple models, and improves assembly flexibility.

[0021] (4) Excellent structural integrity: The negative electrode / electrolyte layer and positive electrode film / current collector are pre-composite by "roll-to-roll" method, and then the whole is die-cut and stacked, which ensures good interfacial contact and structural consistency between functional layers, which is beneficial to improving the compaction density and electrochemical performance of the battery. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of the assembly method of the sulfide all-solid-state battery of Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the positive electrode film roll structure in an embodiment of the present invention; Figure 3 This is a schematic diagram of the transfer printing process; Figure 4 This is a side view diagram of the transfer printing process; Figure 5 This is a schematic diagram of the structure of the positive electrode composite coil A prepared according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of the positive electrode composite sheet A prepared according to an embodiment of the present invention; Figure 7 This is a schematic diagram of using a suction cup to pick up the positive composite electrode A in an embodiment of the present invention; Figure 8 This is a schematic diagram of the positive electrode composite sheet and the negative electrode composite sheet being pressed and bonded together by rollers in an embodiment of the present invention; Figure 9 This is a schematic diagram of the continuous feeding of the positive electrode composite sheet to the negative electrode composite coil and continuous rolling and bonding in an embodiment of the present invention. (a) is an isometric view and (b) is a side view. Figure 10 This is a schematic diagram of the bonding process for the positive electrode composite sheet in an embodiment of the present invention; Figure 11 This is a schematic diagram of the stacked sheets according to an embodiment of the present invention; Figure 12 This is a process flow diagram of an alternative assembly method according to an embodiment of the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0024] Example 1

[0025] This embodiment provides a specific method for assembling a sulfide all-solid-state battery, the process flow of which is as follows: Figure 1 As shown, the steps are as follows: S1: Positive electrode film roll preparation: A continuous positive electrode film roll with a thickness of 180 μm and a height of 104 mm is prepared by dry processing including high-speed mixing, fiberization, granulation, and rolling, according to the mass ratio of NCM (positive electrode active material): sulfide electrolyte powder: PTFE (binder): VGCF (conductive agent) = 82:15:1.5:1.5. Figure 2 (As shown).

[0026] S2: Preparation of Positive Electrode Composite Roll A: A carbon-coated aluminum foil with a thickness of 14 μm and a carbon coating layer of 1 μm on each side is selected. The height of the carbon-coated area is 105 mm, and the height of the tab is 20 mm. Using a roll-to-roll method, the two layers of the positive electrode film are aligned in the center and laminated onto both sides of the carbon-coated aluminum foil using a transfer process via a roller press, forming a positive electrode composite roll A with a total thickness of approximately 376 μm (see schematic diagram of the transfer process). Figure 3 , Figure 4 As shown, the positive electrode composite coil A is as follows Figure 5 (As shown).

[0027] S3: Preparation of Positive Composite Electrode A: The positive composite electrode roll A is cut into sheets of predetermined dimensions using a metal mold to obtain positive composite electrode A. Its dimensions are: height 104mm, width 84mm, and the width and height of the tab blank area are 15mm and 20mm respectively (e.g., ...). Figure 6 (As shown).

[0028] S4: Electrolyte membrane roll preparation: Sulfide electrolyte powder, binder and lithium salt are uniformly mixed in a mixed solvent of toluene and isobutyl isobutyrate at a mass ratio of 94:4.5:1.5 (solid content 27%), then coated on PET substrate, dried and slit into electrolyte membrane rolls with a height of 105mm and a thickness of 50μm.

[0029] S5: Preparation of negative electrode functional coil: On the surface of the carbon-coated area of ​​the negative electrode carbon-coated copper foil (total thickness 14μm, carbon-coated area height 105mm, tab blank height 20mm), a ZnO functional layer is deposited by magnetron sputtering to obtain a negative electrode functional coil with a total thickness of approximately 16μm.

[0030] S6: Preparation of the negative electrode composite roll: Using a roll-to-roll method, the two layers of the electrolyte membrane are aligned in the center and then laminated to both sides of the negative electrode functional roll using a roller press and a transfer process, forming a negative electrode composite roll with a total thickness of approximately 116 μm (refer to the transfer process). Figure 2 and Figure 3 ).

[0031] S7: Bonding: The positive composite electrode A obtained in step 3 is transferred to the surface of the negative composite electrode roll obtained in step 6 by means of suction cup (e.g., ...). Figure 7 As shown), and further compacted and composited by roller pressing (as shown). Figure 8 (As shown). The spacing between each positive composite electrode A is 10mm.

[0032] S8: Dispensing and Curing: Apply UV adhesive using a high-precision dispensing machine along the periphery of the coated area (positive electrode film) of the bonded positive electrode composite sheet A. The width of the adhesive frame is 2mm, and the thickness matches that of the positive electrode composite sheet A (approximately 376μm). Then, use UV light irradiation to crosslink and cure the UV adhesive, forming a non-flowing, ready-to-apply adhesive frame (e.g., ...). Figure 10 (As shown).

[0033] S9: Electrode unit preparation: Die-cut along the outer edge of the cured adhesive frame to obtain the electrode unit.

[0034] S10: Core Preparation: 20 layers of electrode units are stacked, and then a layer of negative electrode composite sheet of the same size, die-cut from the same negative electrode composite roll, is placed on the outermost layer to form the core. (e.g.) Figure 11 (As shown) S11: Battery Finished Product Preparation: The core is placed in an aluminum-plastic film bag, vacuumed, and further compacted under isostatic pressure of 550~600MPa. The compacted core is then removed, and the positive and negative tabs are pre-welded and final-welded before being placed into a new aluminum-plastic film forming cavity. Side sealing and final sealing are performed sequentially to complete the preparation of the all-solid-state battery.

[0035] Example 2

[0036] This embodiment, based on Embodiment 1, adds a tab protection step: At the junction of the carbon-coated areas of the carbon-coated aluminum foil and carbon-coated copper foil and the blank areas of the tabs, a layer of Al2O3 slurry is pre-coated and dried. Subsequent assembly steps are the same as in Embodiment 1. Adhesive is applied to this side (e.g., Figure 5 (As shown) can effectively prevent tab tearing during subsequent isostatic pressing or battery cycling.

[0037] Example 3

[0038] This embodiment provides an alternative solution (process as follows) Figure 12 (as shown) Preparation of "positive electrode composite sheet B": First, roll-press a composite positive electrode film on both sides of the carbon-coated aluminum foil, then roll-press a composite sulfide electrolyte film on the outer side, and then die-cut it into sheets.

[0039] The aforementioned positive composite electrode B is transferred and bonded to a continuous carrier consisting only of negative functional electrode rolls (excluding the composite electrolyte membrane).

[0040] The subsequent dispensing, curing, die-cutting and stacking steps are similar to those in Example 1, and finally a negative electrode functional unit (non-composite unit) is covered on the top layer.

[0041] This solution also realizes the integrated assembly concept of the present invention and is applicable to different battery structure designs.

[0042] The technical solution of the present invention has the following advantages: (1) Integrated stacking technology reduces the stacking efficiency caused by stacking multiple components; (2) The glue-coated frame technology allows for a tighter fit with the electrode sheet, reducing assembly abnormalities that may be caused by prefabricated frames such as polymer frames or prefabricated glue frames. (3) The glue-coating frame technology allows for easy modification of size and thickness, reducing the need for modifications to the new molded frame size that may result from model changes; (4) The positive and negative electrode rolls are rolled together and then die-cut as a whole after being rolled up, which improves the composite effect compared with single-piece composite.

[0043] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for assembling an all-solid-state battery, characterized in that, The process includes the following steps: S1: Provide a continuous negative composite electrode roll as a carrier, transfer the pre-made positive composite electrode sheet and attach it to the surface of the negative composite electrode roll at a predetermined interval; S2: Apply adhesive around each of the positive electrode composite sheets, and after curing, form an adhesive frame surrounding the positive electrode composite sheet; S3: Die-cut along the outer contour of the glue-coating frame according to a fixed outer contour size to obtain an electrode unit containing a positive composite electrode sheet, a glue-coating frame and a lower part of the negative composite electrode roll; S4: Stack multiple electrode units to obtain a stack, and cover the top layer of the stack with a negative electrode composite unit to form a battery core; The negative electrode composite unit is a segment die-cut from the negative electrode composite coil, and its die-cutting size is the same as the outer contour size used to die-cut the electrode unit in step S3. In step S2, the adhesive is a UV-curable adhesive, which is applied by a dispensing machine and cured by ultraviolet light to form the adhesive frame. In step S1, the method for preparing the negative electrode composite electrode roll is as follows: two layers of sulfide solid electrolyte membrane are rolled and laminated onto both sides of a negative electrode functional electrode roll in a roll-to-roll manner. The method for preparing the positive electrode composite sheet is as follows: two layers of positive electrode film are rolled and laminated on both sides of a layer of carbon-coated aluminum foil in a roll-to-roll manner to form a positive electrode composite roll, and then die-cut and punched into sheets, with tabs reserved. The negative electrode functional roll is a composite material roll with a metal or metal oxide functional layer formed on both sides of a carbon-coated copper foil by thermal evaporation or magnetron sputtering; the thickness of the functional layer on one side is 0.2~10μm.

2. The assembly method of an all-solid-state battery according to claim 1, characterized in that, In step S1, the transfer is achieved by a vacuum chuck or a continuous conveyor belt with vacuum suction holes; the bonding is achieved by flat plate pressing or round roller pressing; and / or, the spacing between adjacent positive electrode composite sheets is ≥5mm.

3. The assembly method of an all-solid-state battery according to claim 1, characterized in that, The thickness of the carbon-coated copper foil is 4~8μm, and the thickness of the carbon coating layer on one side is 1~8μm; The aluminum foil with carbon coating has a thickness of 9~16μm and a carbon coating thickness of 1~8μm on one side; the UV curable adhesive is a liquid mixture of light-curing resin, diluent, initiator and functional filler, with a viscosity of 500~30000 CPS.

4. The assembly method of an all-solid-state battery according to claim 1, characterized in that, The height of the positive electrode film in the positive electrode composite sheet is 0-2 mm smaller than the height of the sulfide solid electrolyte film in the negative electrode composite sheet. The adhesive-coating frame has a frame-shaped structure. Its inner edge dimensions match the dimensions of the positive electrode film in the positive electrode composite sheet, and its outer edge dimensions are 1-5 mm larger than the inner edge dimensions. Its cured thickness differs from the thickness of the positive electrode composite sheet by less than ±100 μm.

5. The assembly method of an all-solid-state battery according to claim 1, characterized in that, Also includes: At the junction of the carbon-coated area of ​​the carbon-coated aluminum foil or carbon-coated copper foil and the blank area of ​​the tab, a side coating layer is pre-coated or formed simultaneously with the adhesive frame; the material of the side coating layer is Al2O3, SiO2 or UV adhesive.

6. The assembly method of an all-solid-state battery according to claim 1, characterized in that, In step S2, the positive composite electrode sheet is replaced with positive composite electrode sheet B, and in step S1, the negative composite electrode roll is replaced with a negative functional electrode roll; the structure of the positive composite electrode sheet B is as follows: on both sides of the carbon-coated aluminum foil, a positive electrode film and a sulfide solid electrolyte film are rolled and laminated sequentially from the inside to the outside; the positive composite electrode sheet B is prepared by rolling and laminating two layers of sulfide solid electrolyte film on the outside and two layers of positive electrode film on the inside of the carbon-coated aluminum foil in a roll-to-roll manner under set parameters, and die-cutting and punching the sheet according to the size of the positive composite electrode sheet B, leaving the tab position.

7. An all-solid-state battery, characterized in that, Prepared by the assembly method of any one of claims 1-6, the battery includes an aluminum-plastic film encapsulation shell and a stacked battery cell located inside the shell, wherein the battery cell is composed of multiple positive electrode / electrolyte / negative electrode units separated and positioned by an in-situ cured adhesive frame.

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