Adhesive tape for battery
By designing adhesive tape for batteries, the problems of high electrode scrap rate and numerous safety hazards in wound core packs were solved, achieving a comprehensive improvement in electrode utilization and battery safety, reducing production costs and increasing production yield.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 济宁仁盛新能源有限公司
- Filing Date
- 2026-02-05
- Publication Date
- 2026-04-24
AI Technical Summary
In the current battery production process, the wound-type core pack has problems such as high electrode scrap rate, many safety hazards and low production efficiency. In particular, there are problems such as cost loss due to increased electrode length, ion transport obstruction by electrode winding joints, easy cracking at electrode bending points and high probability of short circuit.
Design a battery adhesive tape comprising a support layer, a base film layer, an adhesive layer, and a transition layer. By optimizing materials and structure, ensure ion conductivity, adhesion, and tensile strength. Suitable for protection of electrode defects, junctions, and core corners, reducing the risk of short circuits.
Improve electrode utilization, reduce production costs, enhance battery safety and production yield, ensure full utilization of battery capacity, and reduce short circuits and scrap caused by foreign objects and burrs.
Smart Images
Figure CN121914640A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of battery manufacturing technology, and in particular to an adhesive paper for batteries. Background Technology
[0002] Lithium-ion batteries, with their advantages of high energy density, long cycle life, environmental friendliness, and safety, are increasingly widely used in the power and energy storage fields. Sodium-ion batteries, on the other hand, with their high safety, abundant raw material sources, and low cost, are gradually becoming an important supplement to lithium-ion batteries and are also gaining a foothold in the power and energy storage fields. Currently, the cell packs of batteries used in power and energy storage mostly adopt a wound structure, consisting of positive electrode plates, negative electrode plates, and a separator wound together. They are divided into cylindrical and square types, and the positive and negative electrode plates usually have more than one tab to meet current transmission requirements.
[0003] In the actual production process of batteries, wound-type core packs have many technical challenges:
[0004] First, the spacing between the multiple tabs of the square wound core pack is unique. If there is a defect in any position of the electrode, the entire electrode will be scrapped. As the energy density and single cell capacity of the battery increase, the length of the electrode is constantly increasing. Some electrode lengths have reached more than 17m. The cost of the positive electrode accounts for more than 40% of the cost of a single cell, and the cost of the negative electrode accounts for more than 30%. Scrapping the electrode will cause huge cost losses.
[0005] Secondly, in order to improve production efficiency, the electrode sheets are usually made into electrode rolls first. However, it is difficult to precisely control the total length of the electrode roll to be an integer multiple of the length of the electrode sheet required for a single roll core. Excess electrode sheets can only be scrapped, resulting in a low electrode sheet manufacturing qualification rate, generally between 95% and 98%. At the same time, the termination tape or high-temperature tape used in the electrode roll splicing process can hinder ion transport, reduce battery capacity, and during battery cycling, the negative electrode sheet at the splicing position is prone to lithium plating, which poses a serious safety hazard.
[0006] Secondly, at the corners of square wound core packs, especially the inner coils of electrodes, the bending radius is small, making the electrodes prone to cracking and material loss, which can lead to battery safety issues. Although adhesive tape is used for protection, existing tapes with insufficient ionic conductivity cannot completely eliminate safety hazards. In addition, burrs or material loss at the electrode cutting points can affect battery safety. Existing protective tapes often lack ionic conductivity, which affects battery capacity and poses safety risks. The probability of short circuits caused by foreign objects or burrs in wound or stacked core packs is over 3‰. Core packs that have short-circuited are usually scrapped, further reducing production yield.
[0007] Therefore, developing a battery adhesive tape that combines good ion conductivity, adhesion, and tensile strength, and is suitable for multiple application scenarios, is of great significance for reducing production costs and improving battery safety and production yield. Summary of the Invention
[0008] The main objective of this invention is to provide a battery adhesive paper that can effectively solve the problems in the prior art.
[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0010] Option 1:
[0011] A battery adhesive paper includes a support layer, a base film layer and an adhesive layer, and a transition layer can be provided between the base film layer and the adhesive layer according to actual needs.
[0012] As a further description of the above technical solution, the support layer is a double-layer or triple-layer adhesive tape:
[0013] Double-layer structure: Composed of a base tape layer and an adhesive layer B. The non-adhesive side of the base tape undergoes release treatment to ensure that it does not adhere to or only weakly adheres to the adhesive layer. The base tape material can be one or more of polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, polyimide, polyester film, polyvinyl chloride film, cotton cloth, and glass cloth. To improve the adhesion between the adhesive layer B and the base tape, the base tape can be pretreated by cleaning and surface activation. The adhesive layer B is a self-adhesive material, which can be one or more of rubber-based pressure-sensitive adhesive, acrylic-based pressure-sensitive adhesive, and silicone-based pressure-sensitive adhesive. It has strong adhesion to the base tape but weak adhesion to the non-adhesive side of the base film layer, and can be easily peeled off from the surface of the base film layer, facilitating construction operations.
[0014] Three-layer structure: Composed of adhesive layer A, base tape layer and adhesive layer B. Both adhesive layers A and B are self-adhesive. The material of adhesive layer B is the same as that of adhesive layer B in the two-layer structure. Its adhesion to the base tape is greater than its adhesion to the non-adhesive surface of the base film layer, and it can be peeled off from the surface of the base film layer. Adhesive layer A is incompatible with the adhesive layer, and the surface energy difference between the two is ≥5mN / m. When the adhesive layer is an acrylic pressure-sensitive adhesive, the adhesive layer A is a natural rubber pressure-sensitive adhesive.
[0015] As a further description of the above technical solution, the base film layer is an organic microporous membrane, which serves as a key channel for ion transport. Its material includes one or more of polyethylene, polypropylene, polyimide, nonwoven fabric, polyethylene terephthalate, and polyetheretherketone. The preparation method can be one or more of dry, wet, and electrospinning methods, with wet-processed polyethylene organic microporous membranes being preferred. The porosity of the organic microporous membrane is 20%~80%, the pore size is 30~200nm, and the thickness is 2~20μm. Polyethylene membranes with a porosity greater than 60% and a thickness ≤7μm are preferred to ensure ion transport efficiency.
[0016] As a further description of the above technical solution, a transition layer is disposed between the base film layer and the adhesive layer to enhance the adhesion between the two. The material includes one or more of ceramics, polyvinylidene fluoride, polyimide particles, melamine cyanurate, polymethyl methacrylate, and lithium lanthanum zirconium oxide. One or more adhesives of polyacrylic acid, polyvinylidene fluoride, and PAA are added. After the components are mixed evenly, they are applied to the surface of the base film layer. The thickness of the transition layer is 0~10μm, preferably less than 3μm, more preferably 1μm or less, to avoid excessively increasing the thickness of the adhesive tape and affecting battery assembly.
[0017] As a further description of the above technical solution, the adhesive layer is coated on the surface of the base film layer or transition layer, and is composed of an adhesive and additives. The adhesive is one or more of acrylic pressure-sensitive adhesive, silicone pressure-sensitive adhesive, polyurethane adhesive, acrylic adhesive, and sulfonic acid-based pressure-sensitive adhesive, preferably acrylic pressure-sensitive adhesive. The additives are selected according to the battery type. When applied to lithium-ion batteries, the additives contain one or more of lithium-ion conductive agents, lithium-ion conductive additives, electrolyte wetting agents, and lithium-ion ionomers. When applied to sodium-ion batteries, the additives contain sodium-ion conductive agents and sodium-ion conductive additives. One or more of the additives and electrolyte wetting agents are included, and the mass ratio of each component of the additive is (0~100):(0~100):(0~100); the mass ratio of the binder to the additive is 20:(0~20), preferably 20:2; the thickness of the adhesive layer is 1~50μm, preferably within 10μm, which can be adjusted according to the actual application scenario; in addition, to further optimize the performance of the adhesive paper, one or more of the following can be added to the adhesive layer: ceramics, polyvinylidene fluoride, polyimide particles, melamine cyanurate, polymethyl methacrylate, and lithium lanthanum zirconium oxide.
[0018] As a further description of the above technical solution, the ionic conductive agent includes one or more of the following: sulfide electrolyte, oxide electrolyte, polymer electrolyte, halide electrolyte, carbon-based conductive agent, and ionic liquid in lithium-ion solid electrolytes. The carbon-based conductive agent may be sulfonated graphene, graphene oxide, or carbon nanotubes. The lithium-ion conductive additive includes one or more of the following: lithium compounds such as lithium carbonate, lithium phosphate, lithium oxide, lithium hydroxide, lithium fluoride, lithium nitrate, lithium sulfate, lithium sulfite, and lithium sulfonate, which are soluble or slightly soluble in lithium-ion electrolytes, as well as lithium-containing substances grafted onto other substances. The electrolyte wetting agent includes one or more of the following: polyvinylidene fluoride that can form a gel with the electrolyte and porous polymers that can adsorb the electrolyte.
[0019] As a further description of the above technical solution, the sodium ion conductive agent includes one or more of the following: sulfide electrolyte, oxide electrolyte, polymer electrolyte, and ionic liquid in sodium ion solid electrolytes; the sodium ion conductive auxiliary agent includes one or more of the following: sodium compounds such as sodium carbonate, sodium sulfate, sodium phosphate, sodium fluoride, sodium nitrate, sodium sulfite, and sodium sulfonate that are soluble or slightly soluble in sodium ion electrolytes, and sodium-containing substances grafted onto other substances.
[0020] Option 2:
[0021] A battery adhesive paper includes a support layer, an adhesive layer, a base film layer and an adhesive layer, a transition layer may be provided between the base film layer and the adhesive layer, and a release layer may be provided on the surface of the support layer.
[0022] As a further description of the above technical solution, the support layer is a double-layer or triple-layer adhesive tape:
[0023] Double-layer structure: It consists of a base layer and an adhesive layer B. The base layer is made of one or more of polypropylene, polycarbonate, polyethylene or other plastic materials. The non-adhesive side of the base layer is released to ensure that it does not adhere to the adhesive layer.
[0024] Three-layer structure: Composed of adhesive layer A, base layer and adhesive layer B. Adhesive layers A and B are both self-adhesive. Adhesive layer B is made of one or more of the following: rubber-based pressure-sensitive adhesive, acrylic-based pressure-sensitive adhesive, and silicone-based pressure-sensitive adhesive. Its adhesion to the base layer is greater than its adhesion to the non-adhesive surface of the base film layer, and it can be peeled off from the surface of the base film layer. Adhesive layer A is incompatible with the adhesive layer, and the surface energy difference between the two is ≥5mN / m. When the adhesive layer is an acrylic-based pressure-sensitive adhesive, adhesive layer A is a natural rubber-based pressure-sensitive adhesive.
[0025] As a further description of the above technical solution, the adhesive layer material is polyvinylidene fluoride or polymethyl methacrylate, which is applied to the surface of the base film layer to form a single-sided adhesive-coated diaphragm. Then, the adhesive layer is laminated to the surface of the base tape that has not undergone release treatment by heat bonding, so as to achieve a stable connection between the support layer and the base film layer.
[0026] As a further description of the above technical solution, the material, composition, and parameter requirements of the base film layer, transition layer, and adhesive layer are consistent with those of Solution 1, ensuring that the adhesive paper has excellent ion conductivity, adhesion, and tensile strength.
[0027] The battery adhesive tapes described above can be processed into sheets or rolls to suit different production scenarios. During battery production, the adhesive tape has suitable adhesion to the surfaces of the positive electrode, negative electrode, and separator, and possesses sufficient tensile strength to withstand stretching and bending during production. When electrolyte is injected into the battery, the additives in the adhesive tape interact with the electrolyte, giving the adhesive tape high ion conductivity and ensuring that ions can pass through the adhesive tape bonding location normally without affecting the full utilization of the battery capacity.
[0028] In both of the above methods, sulfonic acid-based pressure-sensitive adhesives can be modified through chemical modification or post-treatment modification. Chemical modification can be achieved by introducing monomers containing sulfonic acid groups, such as sodium styrene sulfonate or acrylamide-2-methylpropanesulfonic acid, into the polymer chain of the pressure-sensitive adhesive through techniques such as free radical polymerization, ionic polymerization, or graft copolymerization. For example, sulfonated monomers, such as 2-acrylamido-2-methylpropanesulfonic acid, can be added to acrylic pressure-sensitive adhesives to participate in copolymerization. Post-treatment modification can be performed on the synthesized pressure-sensitive adhesive by sulfonating it, such as using sulfonating agents such as concentrated sulfuric acid or chlorosulfonic acid.
[0029] Compared with the prior art, the present invention has the following beneficial effects:
[0030] 1. The adhesive layer is enriched with ionic conductive agents, conductive additives, and electrolyte wetting agents. Combined with an organic microporous membrane base layer with high porosity, reasonable pore size and thickness, ions can smoothly pass through the adhesive paper after electrolyte injection, completely solving the capacity loss problem caused by the existing adhesive paper hindering ion transport.
[0031] 2. It can be directly used to remove the splice at the defective part of the electrode, to splice the part at the interruption of production, and to replace the splice between electrode rolls. The splice does not need to be removed from the battery, which effectively reduces the scrap of the electrode due to electrode defects, length mismatch, broken strips, etc., significantly improves the electrode utilization rate and reduces the production cost.
[0032] 3. When used for protection at electrode cut points, it can wrap burrs and material spillage to prevent them from causing internal short circuits; when used for protection at the corners of the core package, it can enhance the structural stability of the electrode bending points and prevent the electrode from cracking and spilling material; there is no risk of lithium plating in the connection scenario, which comprehensively improves battery safety.
[0033] 4. It can remedy short circuits caused by foreign objects, burrs, etc., reduce the direct scrapping of short-circuited core packages, and greatly improve the production yield. The support layer has a new three-layer structure design. Through the incompatibility design between adhesive layer A and adhesive layer, it further improves the ease of construction and the stability of adhesive tape use, and is compatible with more adhesive types and scenarios. Attached Figure Description
[0034] Figure 1 This is a schematic diagram of the overall structure of one embodiment of the battery adhesive paper of the present invention;
[0035] Figure 2 This is a schematic diagram of the overall structure of a second embodiment of the battery adhesive paper of the present invention.
[0036] In the diagram: 1. Base film layer; 2. Adhesive layer; 3. Support layer; 4. Adhesive layer. Detailed Implementation
[0037] To make the technical means, creative features, and achieved objectives of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.
[0038] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for 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 invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.
[0039] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0040] Please see Figures 1-2 This invention provides a technical solution: a battery adhesive paper.
[0041] Example 1: Adhesive paper for lithium-ion batteries (Scheme 1, no transition layer, double support layer)
[0042] Preparation of support layer 3: A 12μm thick polyester film was selected as the base tape and cleaned with anhydrous ethanol and then subjected to plasma surface activation treatment; an acrylic pressure-sensitive adhesive was used as adhesive layer B and coated on one side of the base tape by micro-grooving, with a coating thickness of 5μm; the non-adhesive surface of the base tape was coated with a silicone release agent to ensure weak adhesion to the adhesive layer, and after drying at room temperature, a double-layer support layer was obtained.
[0043] Pretreatment of base film layer 1: A polyethylene organic microporous membrane prepared by wet method is selected as base film layer 1, with a porosity of 65%, a pore size of 60nm and a thickness of 7μm. One side of the base film layer 1 is subjected to corona treatment to increase the surface tension to more than 38mN / m.
[0044] Preparation of adhesive and adhesive layer 2: Weigh 100 parts of acrylic pressure-sensitive adhesive, 30 parts of toluene solvent and 0.5 parts of antioxidant according to the mass ratio, stir and mix evenly, add 1 part of polyisocyanate crosslinking agent, and cure at room temperature for 4 hours to obtain the base adhesive; Take 20g of base adhesive, add 1g of lithium-ion conductive agent (oxide electrolyte) and 0.5g of lithium-ion conductive additive (lithium fluoride), stir at high speed for 30min until uniform, adjust the viscosity to 2500mPa・s, and obtain the adhesive layer 2 coating liquid.
[0045] Composite and molding: The adhesive layer 2 coating liquid is applied to one side of the base film layer 1 after corona treatment, with a coating thickness of 10μm, and dried in an oven at 80℃ for 3min; the adhesive layer B of the support layer 3 is composited with the other side of the base film layer 1 and rolled into a roll semi-finished product; the semi-finished product is placed in a curing chamber at 75℃ for 12h, cut into 50mm wide narrow strips, and vacuum-sealed with aluminum-plastic composite film to obtain the adhesive paper for lithium-ion batteries.
[0046] Example 2: Adhesive paper for lithium-ion batteries (Scheme 1, including transition layer and double support layer)
[0047] Preparation of support layer 3: Polypropylene film with a thickness of 10μm is selected as the base tape. After cleaning, a 4μm thick silicone pressure-sensitive adhesive (adhesive layer B) is coated on one side. The non-adhesive surface is treated with fluorine release agent and then dried for later use (double-layer structure support layer).
[0048] Base film layer 1 pretreatment: The polyimide organic microporous membrane prepared by electrospinning has a porosity of 70%, a pore size of 50nm, and a thickness of 5μm, and does not require surface activation treatment.
[0049] Transition layer preparation: Ceramic particles (alumina) and polyacrylic acid binder are mixed at a mass ratio of 9:1. An appropriate amount of deionized water is added to adjust the viscosity of the slurry. The mixture is then applied to one side of the base film layer with a coating thickness of 1 μm and dried at 100℃ for 5 min to form a transition layer.
[0050] Preparation of adhesive layer 2: Take 20g of acrylate pressure-sensitive adhesive as the base adhesive, add 0.8g of lithium-ion conductive agent (carbon-based conductive agent - carbon nanotube) and 1g of electrolyte wetting agent (polyvinylidene fluoride), ultrasonically disperse for 20min, and adjust the viscosity to 2000mPa·s.
[0051] Composite and molding: Apply adhesive layer 2 to the surface of the transition layer with a thickness of 8μm and dry at 80℃ for 4min; after being composited with support layer 3, roll it up, cure at 70℃ for 15h, cut it into sheets, and seal and package it to obtain the finished product.
[0052] Example 3: Adhesive tape for lithium-ion batteries (Scheme 2, including release layer and double support layer)
[0053] Preparation of support layer 3: Polyethylene terephthalate film with a thickness of 15 μm is selected as the base tape. One side of the film is released (with silicone release agent) to ensure that it does not adhere to the adhesive layer 2. A 5 μm thick rubber-type pressure-sensitive adhesive (adhesive layer B) is applied to the other side of the base tape. After drying, a double-layer structure support layer 3 is obtained.
[0054] Composite of base membrane layer 1 and adhesive layer 4: Wet-process polypropylene organic microporous membrane is selected as base membrane layer 1, with a porosity of 60%, pore size of 80nm, and thickness of 8μm; polyvinylidene fluoride is used as adhesive layer material, dissolved in N-methylpyrrolidone to prepare a 5% concentration solution, which is coated on one side of base membrane layer 1 with a thickness of 3μm, and dried at 120℃ for 10min to form a single-sided coated diaphragm; adhesive layer 4 of the coated diaphragm is composited with adhesive layer B of support layer 3 by heat bonding (120℃, 0.3MPa pressure), and then cooled to room temperature.
[0055] Preparation of transition layer and adhesive layer 2: The transition layer is made of polyimide particles and polyvinylidene fluoride adhesive (mass ratio 8:2), coated on the other side of the base film layer 1 with a thickness of 0.8μm, and dried at 110℃ for 6min; 20g of polyurethane adhesive is used as the base adhesive, 1.5g of lithium ion polymer and 0.5g of ceramic particles (zirconia) are added, stirred evenly and then coated on the surface of the transition layer with a thickness of 12μm, and dried at 90℃ for 5min.
[0056] Release layer preparation: Polysiloxane release agent was applied to the surface of support layer 3 and cured at 130℃ for 6 hours to form a 25μm thick release layer. The peel force was tested to be 3N / m.
[0057] Forming and Packaging: After winding, cure for 8 hours, cut into the required specifications, and seal and package to obtain the finished product.
[0058] Example 4: Adhesive paper for sodium-ion batteries (Scheme 1, no transition layer, double support layer)
[0059] Preparation of support layer 3: A polyethylene film with a thickness of 10 μm was selected as the base tape. After cleaning, a 6 μm thick rubber-type pressure-sensitive adhesive (adhesive layer B) was applied. The non-adhesive surface was treated with a silicone release agent. After drying, a double-layer structure support layer 3 was obtained.
[0060] Pretreatment of base film layer 1: A polypropylene organic microporous membrane prepared by wet method was selected, with a porosity of 55%, a pore size of 100 nm and a thickness of 10 μm. It was prepared by single-sided corona treatment and then used for later use.
[0061] Preparation of adhesive layer 2: Take 20g of sulfonic acid-based pressure-sensitive adhesive as the base adhesive (prepared by graft copolymerization), add 1.2g of sodium ion conductive agent (polymer electrolyte) and 0.8g of sodium ion conductive additive (sodium carbonate), stir and mix evenly, and adjust the viscosity to 3000mPa・s.
[0062] Composite and molding: The adhesive layer 2 is applied to the corona-treated side of the base film layer 1 with a thickness of 15 μm and dried at 85℃ for 4 min; after being composited with the support layer 3, it is rolled up, cured at 80℃ for 10 h, cut into rolls, and sealed and packaged to obtain the adhesive paper for sodium-ion batteries.
[0063] Example 5: Adhesive paper for sodium-ion batteries (Scheme 1, including transition layer and functional additives, three-layer support layer)
[0064] Preparation of support layer 3: Glass cloth was selected as the base tape with a thickness of 20 μm. After cleaning, a 5 μm thick acrylic pressure-sensitive adhesive (adhesive layer B) was applied. A 4 μm thick natural rubber pressure-sensitive adhesive (adhesive layer A, the adhesive layer is acrylic pressure-sensitive adhesive, and the surface energy difference between the two is ≥5 mN / m) was applied on the other side of the base tape. The non-adhesive surface (the surface of adhesive layer A) was treated with release molding to obtain the three-layer structure support layer 3.
[0065] Pretreatment of base film layer 1: Non-woven fabric is selected as base film layer 1 with a porosity of 75%, a pore size of 120nm and a thickness of 12μm. Plasma treatment is used to improve surface activity.
[0066] Transition layer preparation: Melamine cyanurate and polyvinylidene fluoride adhesive were mixed at a mass ratio of 7:3, and an appropriate amount of solvent was added to make a slurry. The slurry was then applied to one side of the base film layer 1 with a thickness of 2 μm and dried at 105℃ for 8 min to cure.
[0067] Preparation of adhesive layer 2: Take 20g of acrylic pressure-sensitive adhesive as the base adhesive, add 0.6g of sodium ion conductive agent (sulfide electrolyte), 1g of electrolyte wetting agent (porous polymer), and add 3g of polymethyl methacrylate particles (functional additive), and stir at high speed for 40min until uniform.
[0068] Composite and molding: The adhesive layer 2 is coated on the surface of the transition layer with a thickness of 18μm and dried at 90℃ for 5min; after being composited with the adhesive layer B of the support layer 3, it is wound up, cured at 75℃ for 14h, cut into sheets, and sealed and packaged to obtain the finished product.
[0069] Example 6: Adhesive paper for sodium-ion batteries (Scheme 2, including release layer and three support layers)
[0070] Preparation of support layer 3: A polycarbonate film with a thickness of 12 μm is selected as the base tape. A 3 μm thick natural rubber type pressure-sensitive adhesive (adhesive layer A, the adhesive layer is acrylic adhesive, and the surface energy difference between the two is ≥5 mN / m) is coated on one side, and a 4 μm thick organosilicon type pressure-sensitive adhesive (adhesive layer B) is coated on the other side. The surface of adhesive layer A is treated with fluorine release to obtain a three-layer structure support layer 3.
[0071] Composite of base film layer 1 and adhesive layer 4: Polyethylene terephthalate organic microporous membrane (dry preparation) was selected with a porosity of 50%, pore size of 150 nm and thickness of 15 μm; polymethyl methacrylate was dissolved in ethyl acetate and coated on one side of base film layer 1 to form an adhesive layer with a thickness of 3 μm, and dried at 80 °C for 6 min; adhesive layer 4 was composited with adhesive layer B of support layer 3 by heat bonding (110 °C, 0.2 MPa).
[0072] Preparation of adhesive layer 2: Take 20g of acrylic adhesive as the base adhesive, add 2g of sodium ion conductive agent (sodium sulfonate) and 1g of electrolyte wetting agent, stir evenly and apply it to the other side of the base film layer 1 with a thickness of 20μm, and dry at 85℃ for 4min.
[0073] Release layer preparation: A fluorinated release agent is applied to the surface of adhesive layer A of support layer 3 and cured at 140℃ for 5 hours to form a 30μm thick release layer with a peel force ≤4N / m.
[0074] Forming and Packaging: After winding, cure for 9 hours, cut to the required width, and seal and package to obtain the finished product.
[0075] Example 7: Adhesive paper for lithium-ion batteries (Scheme 1, including transition layer and three support layers)
[0076] Preparation of support layer 3: A polyester film with a thickness of 12 μm was selected as the base tape and cleaned with anhydrous ethanol and then subjected to plasma surface activation treatment; a 4 μm thick natural rubber type pressure-sensitive adhesive (adhesive layer A, the adhesive layer is an acrylic type pressure-sensitive adhesive, the surface energy difference between the two is ≥5 mN / m) was coated on one side of the base tape, and a 5 μm thick acrylic type pressure-sensitive adhesive (adhesive layer B) was coated on the other side; a silicone release agent was applied to the surface of adhesive layer A, and after drying at room temperature, a three-layer structure support layer was obtained.
[0077] Pretreatment of base film layer 1: A polyethylene organic microporous membrane prepared by wet method was selected as base film layer 1, with a porosity of 68%, a pore size of 55 nm and a thickness of 6 μm. One side of base film layer 1 was subjected to corona treatment.
[0078] Transition layer preparation: Polyimide particles and polyacrylic adhesive are mixed at a mass ratio of 8:2. An appropriate amount of deionized water is added to adjust the viscosity of the slurry. The mixture is then applied to the corona-treated side of the base film layer 1 with a coating thickness of 1.2 μm. The mixture is dried at 100°C for 4 min to form a transition layer.
[0079] Preparation of adhesive layer 2: Take 20g of acrylic pressure-sensitive adhesive as the base adhesive, add 1.2g of lithium-ion conductive agent (carbon nanotube) and 0.8g of electrolyte wetting agent (polyvinylidene fluoride), ultrasonically disperse for 25min, and adjust the viscosity to 2200mPa·s.
[0080] Composite and molding: Apply adhesive layer 2 to the surface of the transition layer with a thickness of 9μm and dry at 80℃ for 3.5min; composite the adhesive layer B of the support layer 3 with the other side of the base film layer 1 and roll it into a roll of semi-finished product; place the semi-finished product in a curing chamber at 72℃ for 13h, cut it into 60mm wide narrow strips, and vacuum seal it with aluminum-plastic composite film to obtain the finished product.
[0081] It should be noted that this invention is an adhesive tape for batteries, and specific performance tests and application verifications are given below:
[0082] Peel strength test: The peel strength of the adhesive tapes prepared in Examples 1-7 was tested according to GB / T2792-2014 standard. The test results showed that the peel strength of the adhesive tapes to the positive electrode, negative electrode and separator was in the range of 50~300N / m, which met the adhesion requirements in the battery production process. Moreover, the peel strength between the three support layers and the base film layer 1 was less than 0.5N / m, which is convenient for construction. In the three-layer support layer 3, there was no adhesion between the adhesive layer A and the adhesive layer 2, which met the incompatibility design requirements.
[0083] Ion conductivity verification: The adhesive tapes of each embodiment were respectively adhered to the positive and negative electrode surfaces of lithium-ion or sodium-ion batteries. After assembling the batteries, electrolyte was injected, and charge-discharge cycle tests were conducted. In the comparative experiment, the surface of the negative electrode of the battery with ordinary adhesive tape was black, indicating no lithium intercalation, while the surface of the negative electrode of the battery with the adhesive tape of this invention was yellow, indicating normal lithium intercalation. This verifies the excellent ion conductivity of the adhesive tape of this invention. According to GB / T20220-2006 standard, the ionic conductivity of the adhesive tape after immersion in electrolyte was tested, and the results showed 1×10⁻³~5×10⁻³ S / cm, while ordinary adhesive tape was only 1×10⁻³. 6 ~5×10⁻ 5 S / cm, meeting the battery ion transport requirements.
[0084] Application effect verification: In electrode splicing scenarios, after using the adhesive tape of this invention, the electrode utilization rate increased from the original 95% to over 97%; in short-circuit core pack repair scenarios, the repair success rate reached over 80%, significantly improving the production yield. During construction, the adhesive tape of the three-layer support layer 3 has no adhesion interference between the adhesive layer A and the adhesive layer 2, and the operation is smoother than that of traditional structural adhesive tape.
[0085] Compared with existing battery adhesive tapes, this invention designs a double or triple-layer support layer, combined with an ion-conductive adhesive layer and a high-performance base film layer, giving the adhesive tape both adhesion and tensile strength. It can be widely used for electrode defect connection, cut-off protection, core pack corner protection, and short-circuit core pack repair. It can reduce electrode scrap rate, eliminate safety hazards, ensure battery capacity, and effectively improve battery production yield and product reliability.
[0086] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.
Claims
1. A type of battery adhesive tape, characterized in that, It includes a base film layer (1), an adhesive layer (2) and a support layer (3), and a transition layer may be provided between the base film layer (1) and the adhesive layer (2); The support layer (3) is a double-layer or triple-layer adhesive tape. The double-layer structure consists of a base layer and an adhesive layer B, and the triple-layer structure consists of an adhesive layer A, a base layer, and an adhesive layer B. In the double-layer structure tape, the non-adhesive surface of the base tape is released and does not adhere to or only weakly adheres to the adhesive layer (2). The base tape is made of one or more of the following materials: polyethylene, polypropylene, polyethylene terephthalate, polycarbonate, polyimide, polyester film, polyvinyl chloride film, cotton cloth, and glass cloth. In the three-layer adhesive tape, adhesive layer A and adhesive layer B are both self-adhesive; the material of adhesive layer B is one or more of rubber-type pressure-sensitive adhesive, acrylic ester-type pressure-sensitive adhesive, and silicone-type pressure-sensitive adhesive. The adhesion force of adhesive layer B to the base tape is greater than the adhesion force to the non-adhesive layer (2) of the base film layer (1), and it can be peeled off from the surface of the base film layer (1). The adhesive layer A and the adhesive layer (2) are incompatible, and their surface energies differ by ≥5mN / m; when the adhesive layer is an acrylic pressure-sensitive adhesive, the adhesive layer A is a natural rubber pressure-sensitive adhesive. The base film layer (1) is an organic microporous membrane, made of one or more of polyethylene, polypropylene, polyimide, nonwoven fabric, polyethylene terephthalate, and polyetheretherketone, and prepared by one or more of dry method, wet method, and electrospinning. The transition layer is disposed between the base film layer (1) and the adhesive layer (2), and the material includes one or more of ceramic, polyvinylidene fluoride, polyimide particles, melamine cyanurate, polymethyl methacrylate, and lithium lanthanum zirconium oxide, and contains one or more adhesives of polyacrylic acid and polyvinylidene fluoride. The adhesive layer (2) is applied to the surface of the base film layer (1) or the transition layer, and is composed of an adhesive and additives. The adhesive is one or more of acrylic pressure-sensitive adhesive, silicone pressure-sensitive adhesive, polyurethane adhesive, acrylic adhesive, and sulfonic acid pressure-sensitive adhesive. When the additive is applied to a lithium-ion battery, it contains one or more of the following: lithium-ion conductive agent, lithium-ion conductive aid, electrolyte wetting agent, and lithium-ion polymer. When the additive is applied to a sodium-ion battery, it contains one or more of sodium-ion conductive agents, sodium-ion conductive aids, and electrolyte wetting agents. The mass ratio of each component of the additive is (0~100):(0~100):(0~100), and at least one component has a mass percentage greater than 0.
2. The battery adhesive tape according to claim 1, characterized in that, The lithium-ion conductive agent includes one or more of the following lithium-ion solid electrolytes: sulfide electrolytes, oxide electrolytes, polymer electrolytes, halide electrolytes, ionic liquids, and carbon-based conductive agents; the lithium-ion conductive additive includes one or more lithium compounds such as lithium carbonate, lithium phosphate, lithium oxide, lithium hydroxide, lithium fluoride, lithium nitrate, lithium sulfate, lithium sulfite, lithium sulfonate, and lithium lanthanum zirconium oxide that are soluble or slightly soluble in lithium-ion electrolytes, as well as lithium-containing substances grafted onto other substances; the electrolyte wetting agent includes one or more of the following polyvinylidene fluoride materials that can form a gel with the electrolyte and porous materials that can adsorb the electrolyte.
3. The battery adhesive tape according to claim 1, characterized in that, The sodium ion conductive agent includes one or more of the following: sulfide electrolyte, oxide electrolyte, polymer electrolyte, and ionic liquid in sodium ion solid electrolytes; the sodium ion conductive auxiliary agent includes one or more of the following: sodium compounds such as sodium carbonate, sodium sulfate, sodium phosphate, sodium fluoride, sodium nitrate, sodium sulfite, and sodium sulfonate that are soluble or slightly soluble in sodium ion electrolytes, and sodium-containing substances grafted onto other substances.
4. The battery adhesive tape according to claim 1, characterized in that, The porosity of the base film layer (1) is 20%~80%, the pore size is no more than 300nm, and the thickness is 2~20μm.
5. The battery adhesive tape according to claim 1, characterized in that, The mass ratio of the adhesive to the additive is 20:(0~20), and the thickness of the adhesive layer is 1~50μm.
6. The battery adhesive tape according to claim 1, characterized in that, The adhesive layer (2) may also contain one or more of the following: ceramics, polyvinylidene fluoride, polyimide particles, melamine cyanurate, polymethyl methacrylate, and lithium lanthanum zirconium oxide.
7. The battery adhesive tape according to any one of claims 1, characterized in that, The support layer (3) has a release layer on its surface away from the transition layer. The release layer is made of one of polysiloxane release film, fluorine release film or paper release film, and has a thickness of 10~50μm. The adhesive layer (2) is formed by coating the surface of the support layer (3) with a release agent and curing it at 120~150℃ for 5~8h. The peel force between the adhesive layer and the support layer is ≤5N / m, which ensures that the adhesive layer (2) is easy to peel off during construction without damaging it.
8. The battery adhesive tape according to any one of claims 1-7, characterized in that, The adhesive tape is in the shape of a sheet or a roll.
9. A type of battery adhesive tape, characterized in that, It includes a base film layer (1), an adhesive layer (2), a support layer (3) and an adhesive layer (4), with a transition layer provided between the base film layer (1) and the adhesive layer (2); The support layer (3) is a double-layer or triple-layer adhesive tape. The double-layer structure consists of a base layer and an adhesive layer B, and the triple-layer structure consists of an adhesive layer A, a base layer, and an adhesive layer B. In the double-layer structure tape, the non-adhesive surface of the base tape is released and does not adhere to or only weakly adheres to the adhesive layer (2). The base tape is made of one or more of polypropylene, polycarbonate, polyethylene or other plastic materials. In the three-layer adhesive tape, adhesive layer A and adhesive layer B are both self-adhesive; the material of adhesive layer B is one or more of rubber-type pressure-sensitive adhesive, acrylic ester-type pressure-sensitive adhesive, and silicone-type pressure-sensitive adhesive. The adhesion force of adhesive layer B to the base tape is greater than the adhesion force to the non-adhesive layer (2) of the base film layer (1), and it can be peeled off from the surface of the base film layer (1). The adhesive layer A and the adhesive layer (2) are incompatible, and their surface energies differ by ≥5mN / m. When the adhesive layer is selected as an acrylic pressure-sensitive adhesive, the adhesive layer A is selected as a natural rubber pressure-sensitive adhesive. The adhesive layer (4) is made of polyvinylidene fluoride or polymethyl methacrylate and is coated on the surface of the base film layer (1) to form a single-sided adhesive diaphragm. The single-sided adhesive diaphragm is bonded to the surface of the base tape without release treatment by heat bonding. The base membrane layer (1) is an organic microporous membrane, and the material includes one or more of polyethylene, polypropylene, polyimide, non-woven fabric, and polyethylene terephthalate. The preparation method is one or more of dry or wet methods.