All-solid-state battery pretreatment method for preventing isostatic pressing short circuit and pollution

Abstract

The invention provides an all-solid-state battery pretreatment method for preventing isostatic pressing short circuit and pollution, which comprises the following steps: step S1, stacking to a target layer number by adopting a full-alignment lamination mode, and then carrying out cold press molding on a battery lamination body; s2, coating the periphery of the battery lamination body with acetoxyl organosilicone UV glue at a uniform speed in a single direction, and then curing the acetoxyl organosilicone UV glue; and S3, cutting oleophobic films, pasting the oleophobic films on the front and back surfaces of the battery lamination body, then putting the battery lamination body into a preformed aluminum-plastic film cavity, and performing thermal packaging under vacuum to form an airtight packaging structure. According to the invention, the sulfide all-solid-state battery is subjected to battery cell edge sealing glue curing and pre-isostatic pressing pretreatment of additional peelable oleophobic layer packaging, so that edge interlayer support and insulation under isostatic pressing are realized, the problem of edge fragmentation of the battery is relieved, short circuit is prevented, the performance of the battery is improved, dual protection is realized, sealing and antifouling are realized, and the service life of the battery is prolonged. The internal edge sealing failure of the battery assembly can be prevented, and sulfide electrolyte is prevented from being exposed to the environment.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery technology, and more specifically, to a pretreatment method for all-solid-state batteries to prevent isostatic short circuits and contamination. Background Technology

[0002] Isostatic pressing is one of the most effective process methods to solve the problems of solid-solid interface contact and densification in the manufacturing process of all-solid-state batteries.

[0003] A Chinese patent with publication number CN114072951B discloses a hydraulic isostatic pressing process for solid-state batteries, proposing various arrangements to increase the contact between the electrolyte and active materials of the battery cell. The battery cell can be inserted into a housing such that it is immersed in a liquid. The housing can be sealed, and pressure and heat can then be applied to the liquid. The battery cell can then be removed from the housing and used as part of a sealed battery module.

[0004] In existing technologies, isostatic pressing still presents the following technical challenges in the practical application of sulfide all-solid-state batteries: 1. Short circuit problem and structural integrity damage of all-solid-state batteries during isostatic pressing: On the one hand, it is mainly due to the contact between the edges of the positive and negative electrode plates during isostatic pressing. On the other hand, under the high pressure of isostatic pressing, due to the brittleness of sulfide materials and the stress concentration at the edge of the battery, fracture cracks are easily generated and propagated. 2. Sealing failure and contamination issues: Traditional packaging materials (such as aluminum-plastic film) cannot withstand ultra-high pressure and are prone to edge damage during isostatic pressing, resulting in hydraulic oil penetration and air exposure, which leads to the failure of the internal edge seal of the battery component and the exposure of sulfide electrolyte to the environment.

[0005] Therefore, there is a need for a pretreatment method for all-solid-state batteries that can prevent isostatic short circuits and contamination. This method can solve the problems of edge short circuits, sealing failures, and contamination in all-solid-state batteries during the isostatic pressing process. It is suitable for the industrial production of high-energy-density solid-state batteries and achieves high sealing, short-circuit prevention, and contamination prevention effects. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the purpose of this invention is to provide a pretreatment method for all-solid-state batteries that prevents isostatic short circuits and contamination.

[0007] A pretreatment method for all-solid-state batteries to prevent isostatic short circuits and contamination, according to the present invention, includes the following steps: Step S1: Using a fully aligned stacking method, negative electrode sheets coated with sulfide electrolyte layers and NCM positive electrode sheets of matching size are stacked to the target number of layers, and then the battery stack is cold-pressed. Step S2: Using a nylon brush, apply acetoxy-based silicone UV adhesive in a uniform unidirectional direction around the battery stack, and then cure the UV adhesive to form a sealed structure. Step S3: Cut an oleophobic film that matches the size of the battery stack, attach it to both sides of the battery stack, and then place it into a pre-formed aluminum-plastic film cavity. Perform heat sealing under vacuum to form an airtight encapsulation structure.

[0008] Preferably, in step S1, the tabs of the negative electrode sheet coated with a sulfide electrolyte layer of the same size are misaligned and stacked with the tabs of the NCM positive electrode sheet.

[0009] Preferably, in step S1, an electric tablet press is used for cold pressing, and the pressure for cold pressing is 40-50 MPa.

[0010] Preferably, in step S2, the bristle diameter of the nylon brush is in the range of 0.3-0.5mm. After dipping the nylon brush into the acetoxy silicone UV liquid, the excess glue is scraped off at the edge of the container. Each dip is applied to a length of 2-3cm. The brush is applied unidirectionally and at a uniform speed of 5-10mm / s along the edge of the battery. The nylon brush is at a 45° angle to the edge of the battery stack. The application path must be continuous. At the four corners of the battery stack, the brush needs to pause before turning the angle to avoid breaking or accumulating glue. A glue layer with a thickness of 100-150μm is formed on the four sides of the battery stack for sealing.

[0011] Preferably, in step S2, a 365nm wavelength UV lamp is used to cure the UV adhesive with an intensity ≥50mW / cm², and the lamp is irradiated for 60 seconds at a distance of 10cm. The irradiation is performed twice to ensure no shadow area. Then, the UV adhesive is cured with hot air at 70℃ for 30 minutes.

[0012] Preferably, in step S3, the oleophobic film includes a fluorinated polymer-based peelable film with a thickness of 50±5μm and a 5mm margin around the edges.

[0013] Preferably, the battery cell with fluorinated polymer oleophobic film coated on both sides is placed into a pre-formed aluminum-plastic film cavity, and the tabs pass through the pre-reserved holes in the film layer.

[0014] Preferably, in step S3, in 10 -3 Vacuum encapsulation under Pa.

[0015] Preferably, after pretreatment, isostatic pressing is performed, then the oleophobic film is peeled off and the interface integrity is checked, and finally welding and packaging are carried out to form a soft-pack battery cell.

[0016] Preferably, isostatic pressing is performed using 300 MPa oil pressure, and the oleophobic film is peeled off after holding the pressure for 10 minutes.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention achieves edge interlayer support and insulation under isostatic pressing by pre-treatment of sulfide all-solid-state batteries, including edge sealing curing and additional peelable oleophobic layer encapsulation. This alleviates the problem of battery edge breakage, prevents short circuits, improves battery performance, provides dual protection, and seals against contamination. It can prevent the failure of the internal edge seal of the battery module and prevent the sulfide electrolyte from being exposed to the environment. It is compatible with ordinary isostatic pressing processes and is conducted in an oxygen-free environment throughout the process, which can avoid sulfide degradation. It is suitable for the industrial production of high-energy-density solid-state batteries and achieves high sealing, short-circuit prevention, and contamination prevention effects. Attached Figure Description

[0018] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a schematic flowchart illustrating the pretreatment method for all-solid-state batteries that mainly embodies the present invention for preventing isostatic short circuits and contamination. Detailed Implementation

[0019] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0020] like Figure 1 As shown, a pretreatment method for all-solid-state batteries to prevent isostatic short circuits and contamination according to the present invention includes the following steps: Step S1: Using a fully aligned stacking method, negative electrode sheets coated with sulfide electrolyte layers and NCM positive electrode sheets of matching size are stacked to the target number of layers, and then the battery stack is cold-pressed. Step S2: Using a nylon brush, apply acetoxy-based silicone UV adhesive in a uniform unidirectional direction around the battery stack, and then cure the UV adhesive to form a sealed structure. Step S3: Cut an oleophobic film that matches the size of the battery stack, attach it to both sides of the battery stack, and then place it into a pre-formed aluminum-plastic film cavity. Perform heat sealing under vacuum to form an airtight encapsulation structure.

[0021] The core of this application lies in the pretreatment of sulfide all-solid-state batteries before isostatic pressing using a specific adhesive and peelable oleophobic paper, thereby preventing isostatic short circuits and hydraulic oil contamination. Before isostatic pressing, acetoxy-based silicone UV adhesive is used to seal and cure the edges of the fully aligned stacked sulfide all-solid-state batteries. Under high pressure, the UV adhesive provides mechanical support and insulation between the edge electrodes, while also absorbing and evenly distributing the impact force in the bonding area. This achieves interlayer support and insulation between the positive, negative, and electrolyte edges of the sulfide all-solid-state cell, effectively mitigating stress concentration and edge breakage short circuits at the battery edges during isostatic pressing. The acetoxy-based silicone UV adhesive seals the battery edges, and a peelable oleophobic layer is applied to the battery surface. After curing, the acetoxy-based silicone UV adhesive exhibits excellent sealing properties and can undergo secondary moisture curing at room temperature. The peelable oleophobic layer prevents oil contamination of the battery surface. The secondary curing of the edge sealant and the application of the peelable oleophobic layer provide dual protection, sealing against contamination and preventing failure of the internal edge seals of the battery assembly, as well as preventing the sulfide electrolyte from being exposed to the environment.

[0022] In step S1, negative electrode sheets coated with sulfide electrolyte layers of the same size are misaligned and stacked with NCM positive electrode sheets. The electrodes are then cold-pressed using an electric tablet press at a pressure of 40-50 MPa and a temperature of 26 degrees Celsius (room temperature) to promote interfacial contact.

[0023] In step S2, a fine-bristled nylon brush with bristle diameter ranging from 0.3 to 0.5 mm is used. After dipping the brush in acetoxylated silicone UV liquid, excess adhesive is scraped off at the edge of the container. Each dip can cover a length of 2-3 cm. The brush is applied unidirectionally and at a uniform speed of 5-10 mm / s along the edge of the battery. The nylon brush is held at a 45° angle to the edge of the battery stack. The application path must be continuous. At the four corners of the battery stack, the brush should pause slightly before gently turning the angle to avoid interrupting the adhesive or causing adhesive buildup. A 100-150 μm thick adhesive layer is formed on the four sides of the battery stack for sealing. The angled brushing method provides high coverage and a high filling rate, ensuring that the insulating adhesive fills the easily short-circuited areas at the edge of the cell without excessively scratching the battery edge. Multiple dips are required to complete the edge coating of the entire cell; uneven adhesive layers can lead to edge stress.

[0024] The UV adhesive was cured using a 365nm wavelength UV lamp with an intensity ≥50mW / cm². It was irradiated for 60 seconds at a distance of 10cm, and then irradiated twice to ensure no shadow areas. Then, it was cured with 70℃ hot air for 30 minutes to ensure no stress at the interface between the adhesive layer and the sulfide.

[0025] In step S3, the oleophobic film includes a fluoropolymer-based peelable film, such as a PTFE-modified film, with a thickness ranging from 50±5μm. It is cut to the cell size, with a 5mm allowance around the edges for easy peeling. The cell with the fluoropolymer oleophobic film applied to both sides is placed into the pre-formed aluminum-plastic film cavity, with the tabs passing through the pre-drilled holes in the film. (In 10...) -3 Vacuum encapsulation under Pa forms a hermetically sealed encapsulation structure.

[0026] After pretreatment, isostatic pressing is performed, followed by peeling off the oleophobic film and checking the interface integrity. Finally, the cells are welded and packaged into soft-pack cells.

[0027] Isostatic pressing was performed using 300 MPa hydraulic pressure, and the oleophobic film was peeled off after holding the pressure for 10 minutes.

[0028] More specifically, this application is illustrated through the following specific embodiments.

[0029] Step S1, cell stacking; The silicon-carbon anode coated with sulfide electrolyte layer and the NCM811 cathode (load 20mg / cm²) are stacked in a fully aligned stacking manner and cold-pressed at 50MPa. Step S2, edge coating and curing: Using a nylon brush, apply acetoxy-based silicone UV adhesive unidirectionally and at a uniform speed along the four sides of the battery stack, with an adhesive layer thickness of 100-150μm; after coating, cure with 365nm UV light for 60 seconds and 70℃ hot air for 30 minutes to form a continuous sealed structure, preventing edge breakage and short circuit risks during isostatic pressing; this process ensures the sealing performance and mechanical strength of the adhesive layer, while being compatible with subsequent isostatic pressing and encapsulation processes; Step S3: Peelable oleophobic layer application and encapsulation; after the battery cell is cured at the edges with UV adhesive, a fluoropolymer oleophobic film (50μm) is applied to both sides, and then it is installed into an aluminum-plastic film cavity, and then... -3 The gas is heat-sealed under vacuum to form an airtight encapsulation structure; the oleophobic film can be peeled off after isostatic pressing, which has both process protection and interface cleaning functions. Step S4, isostatic pressing: 300MPa oil pressure, hold pressure for 10 minutes, then peel off the oleophobic film and check the interface integrity; Step S5, welding and encapsulation: The oleophobic film can be peeled off after isostatic pressing, which has both process protection and interface cleaning functions. Then the cell is welded and encapsulated into a soft-pack cell.

[0030] This application is further illustrated by the following control and experimental groups: Control group 1 (standard process): Processing method: Raw battery cells without any edge sealing or oleophobic coating. Purpose: To serve as a benchmark, making it easier to highlight problems with existing processes.

[0031] Experimental Group B (edge ​​sealing only): Treatment method: Only edge sealing and curing of the battery cells was performed. Purpose: To independently verify the contribution of edge sealing to resolving short circuit and sealing issues.

[0032] Experimental group C (with only an additional peelable oleophobic coating): Treatment method: A peelable oleophobic layer is applied only to the surface of the battery cell (removed after isostatic pressing). Purpose: To independently verify the contribution of the oleophobic layer to preventing contamination.

[0033] Experimental Group D (Composite Process): Treatment method: Edge sealing and curing + application of a peelable oleophobic layer. Objective: To verify the synergistic effect and final result of the proposed complete pretreatment process.

[0034] After all four groups of cells have undergone different pre-treatments, they must be packaged and soldered under identical conditions (pressure, holding time, environment). After isostatic pressing, the appearance of the battery is observed, and voltage and DC internal resistance (DCIR) tests are performed after soldering and packaging. The voltage is also monitored during 0.5C cycling to check for short circuits.

[0035]

[0036] Table 1 This application achieves edge interlayer support and insulation under isostatic pressing by pre-treatment of sulfide all-solid-state batteries, including edge sealing curing and additional peelable oleophobic layer encapsulation. This alleviates edge breakage issues, prevents short circuits, improves battery performance, provides dual protection, and ensures a sealed and contamination-free environment. It also prevents internal edge seal failure and sulfide electrolyte exposure to the environment. Compatible with conventional isostatic pressing processes, this application utilizes a completely anhydrous and oxygen-free environment to avoid sulfide degradation. It is suitable for the industrial production of high-energy-density solid-state batteries, achieving high sealing, short-circuit protection, and contamination prevention.

[0037] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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. Therefore, they should not be construed as limitations on this application.

[0038] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A full solid-state battery pretreatment method for preventing short circuit and contamination of isostatic pressing, characterized by, Includes the following steps: Step S1: Using a fully aligned stacking method, negative electrode sheets coated with sulfide electrolyte layers and NCM positive electrode sheets of matching size are stacked to the target number of layers, and then the battery stack is cold-pressed. Step S2: Using a nylon brush, apply acetoxy-based silicone UV adhesive in a uniform unidirectional direction around the battery stack, and then cure the UV adhesive to form a sealed structure. Step S3: Cut an oleophobic film that matches the size of the battery stack, attach it to both sides of the battery stack, and then place it into a pre-formed aluminum-plastic film cavity. Perform heat sealing under vacuum to form an airtight encapsulation structure.

2. The full solid-state battery pretreatment method for preventing short circuit and contamination of isostatic pressing according to claim 1, characterized by, In step S1, the tabs of the negative electrode sheet coated with sulfide electrolyte layer of the same size are misaligned and stacked with the tabs of the NCM positive electrode sheet.

3. The full solid-state battery pre-treatment method for preventing short circuit and contamination of isostatic pressing according to claim 1, characterized by, In step S1, an electric tablet press is used for cold pressing, and the pressure for cold pressing is 40-50 MPa.

4. The full solid-state battery pre-treatment method for preventing short circuit and contamination of isostatic pressing according to claim 1, characterized by, In step S2, the bristle diameter of the nylon brush is 0.3-0.5mm. After dipping the nylon brush into the acetoxy silicone UV liquid, scrape off the excess glue at the edge of the container. Apply glue in a single application for a length of 2-3cm. Apply the glue evenly in one direction along the edge of the battery at a speed of 5-10mm / s. The nylon brush should be at a 45° angle to the edge of the battery stack. The application path must be continuous. At the four corners of the battery stack, the brush should pause before turning the angle to avoid breaking or accumulating glue. A glue layer with a thickness of 100-150μm is formed on the four sides of the battery stack for sealing.

5. The isostatic pressing short circuit and contamination prevention full solid-state battery pretreatment method of claim 1, wherein, In step S2, a 365nm wavelength UV lamp is used to cure the UV adhesive with an intensity ≥50mW / cm². The lamp is irradiated for 60 seconds at a distance of 10cm, and the irradiation is done in two stages to ensure no shadow areas. Then, the UV adhesive is cured with 70℃ hot air for 30 minutes.

6. The isostatic pressing short circuit and contamination prevention full solid-state battery pretreatment method of claim 1, wherein, In step S3, the oleophobic film includes a fluorinated polymer-based peelable film with a thickness of 50±5μm and a 5mm margin around the edges.

7. The pretreatment method for all-solid-state batteries to prevent isostatic short circuits and contamination as described in claim 6, characterized in that, The battery cell with fluorinated polymer oleophobic film applied to both sides is placed into a pre-formed aluminum-plastic film cavity, and the tabs pass through the pre-reserved holes in the film.

8. The pretreatment method for all-solid-state batteries to prevent isostatic short circuits and contamination as described in claim 1, characterized in that, The step S3 in 10 -3 under vacuum.

9. The pretreatment method for all-solid-state batteries to prevent isostatic short circuits and contamination as described in claim 1, characterized in that, After pretreatment, isostatic pressing is performed, followed by peeling off the oleophobic film and checking the interface integrity. Finally, the cells are welded and packaged into soft-pack cells.

10. The pretreatment method for all-solid-state batteries to prevent isostatic short circuits and contamination as described in claim 9, characterized in that, Isostatic pressing was performed using 300 MPa hydraulic pressure, and the oleophobic film was peeled off after holding the pressure for 10 minutes.

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