Safety gummed paper and its preparation method and application

Abstract

The application discloses a kind of safety adhesive tape and its preparation method and application, including from top to bottom sequentially superimposed setting release layer, substrate layer, security layer and pressure sensitive adhesive layer;The preparation raw materials of security layer include silane coupling agent modified inorganic filler;The preparation raw materials of silane coupling agent modified inorganic filler include silane coupling agent and inorganic filler;The preparation raw materials of the pressure sensitive adhesive layer include acrylate;The application proposes a kind of safety adhesive tape, can improve the thermal runaway of battery cell, at the same time, reduce the self-discharge caused by tab site welding burr, improve the consistency of battery performance, improve the problem of uneven pressure when battery cell formation.

Description

Technical Field

[0001] This invention belongs to the field of lithium battery technology, specifically relating to a safety adhesive paper, its preparation method, and its application. Background Technology

[0002] As mobile electronic products such as smartphones consume increasingly more power, the capacity and energy density of lithium-ion batteries used are also increasing. Thermal runaway can have extremely serious consequences. Furthermore, burrs are inevitably introduced during battery manufacturing, leading to self-discharge and reducing manufacturing consistency. Thermal runaway problems can typically be mitigated by improving the thermal stability of the positive and negative electrode materials and introducing PTC (Potentially Transmitted Cell) elements. However, improving the thermal stability of the positive and negative electrode materials generally requires multiple rounds of verification, which is costly and time-consuming; introducing PTC elements also has a time lag issue.

[0003] Therefore, developing a safety adhesive tape to improve thermal runaway of battery cells, while reducing self-discharge caused by welding burrs at the electrode tabs, is an urgent task. Summary of the Invention

[0004] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a safety adhesive film comprising a layered safety layer and a pressure-sensitive adhesive layer, which can improve thermal runaway of the battery cell, reduce self-discharge caused by welding burrs at the electrode tabs, improve the consistency of battery performance, and alleviate the problem of uneven pressure during battery cell formation.

[0005] The present invention also provides a method for preparing safety adhesive paper.

[0006] The present invention also provides a secondary battery, the secondary battery comprising the safety adhesive tape.

[0007] According to a first aspect of the present invention, a safety adhesive paper includes a release layer, a substrate layer, a safety layer and a pressure-sensitive adhesive layer stacked sequentially from top to bottom;

[0008] The raw materials for preparing the safety layer include inorganic fillers modified with silane coupling agents;

[0009] The raw materials for preparing the silane coupling agent modified inorganic filler include silane coupling agent and inorganic filler;

[0010] The raw materials for preparing the pressure-sensitive adhesive layer include acrylate.

[0011] The embodiments of the first aspect of the present invention have at least the following beneficial effects:

[0012] This invention provides a safety adhesive paper that solves the problem of the mutual constraint between inorganic filler content and adhesion in single-functional layer safety adhesive paper. This invention employs a layered design with different functional layers, including a release layer, a substrate layer, a safety layer, and a pressure-sensitive adhesive layer, arranged layer by layer. The release layer has a low surface energy, preventing the adhesive paper from sticking together and facilitating winding. The substrate layer provides a carrier for the adhesive coating and a certain strength. The safety layer and pressure-sensitive adhesive layer are separated, allowing for a high content of inorganic filler in the safety layer (the highest content of silane coupling agent-modified inorganic filler reaches 80%) while maintaining good adhesion, thus promoting the performance of the safety adhesive paper. In this invention, due to the high inorganic filler content of the safety layer, its surface is relatively rough after coating. With the synergistic effect of the silane coupling agent, a strong bond is formed between the safety layer and the pressure-sensitive adhesive layer, ensuring the stable functioning of the safety layer. The inorganic filler in the safety layer has good thermal conductivity and flame retardancy, which can improve the thermal runaway of the battery cell. At the same time, it reduces self-discharge caused by welding burrs at the tab positions, improves the consistency of battery performance, and alleviates the problem of uneven pressure during cell formation. The pressure-sensitive adhesive layer provides good adhesion, allowing the adhesive tape to be firmly attached to the positive and negative electrode tab positions of the lithium battery, the electrode material area opposite the electrode tab positions, the transition position between the material area and the empty foil area, and the end position of the core roll. This is conducive to the performance of the safety adhesive tape, making it easier for the battery cell to pass tests such as thermal abuse, overcharge, and high-temperature short circuit. Meanwhile, the pressure-sensitive adhesive layer, with acrylate as the main raw material, keeps the adhesive solution at a viscosity of 1000-10000 mPa·s, ensuring the high viscosity of the pressure-sensitive adhesive layer and facilitating processing. According to some embodiments of the present invention, the safety layer comprises the following raw materials in parts by weight: 80-95 parts acrylate, 1-10 parts hard monomer 1, 1-15 parts functional monomer 1, 1-80 parts silane coupling agent modified inorganic filler 1, 1-20 parts tackifying resin, 0.0005-0.005 parts photoinitiator 1, 0.5-5 parts photoinitiator 2, and 0.0005-0.005 parts chain transfer agent.

[0013] According to some preferred embodiments of the present invention, the safety layer comprises the following raw materials in parts by weight: 85 parts acrylate, 5 parts hard monomer 1, 10 parts functional monomer 1, 60 parts silane coupling agent modified inorganic filler 1, 5 parts tackifying resin, 0.001 parts photoinitiator 1, 1 part photoinitiator 2 and 0.001 parts chain transfer agent.

[0014] According to some embodiments of the present invention, the acrylate includes at least one of isooctyl acrylate (2-EHA) and butyl acrylate (BA).

[0015] According to some embodiments of the present invention, the hard monomer 1 includes at least one of acrylic acid (AA), methyl methacrylate (MMA), and acrylonitrile (AN).

[0016] Functional monomer 1: These monomers mainly contain reactive functional groups, such as hydroxyl, carboxyl, and amide groups. These monomers can crosslink with other monomers, promoting polymerization, accelerating the polymerization rate, and improving polymer stability. The proportions of the above monomers can be adjusted according to the actual application environment of the adhesive tape. Generally, soft monomers (acrylates) are the main component, with a certain amount of hard monomers added to change their glass transition temperature, thereby imparting sufficient cohesive strength. A small amount of functional monomers is then added to give the prepolymer sufficient crosslinking, thereby improving its adhesive properties, thermal stability, and creep resistance.

[0017] According to some embodiments of the present invention, the functional monomer 1 includes at least one of hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), tetrahydrofuran acrylate (THFA), and N,N-dimethylacrylamide (DMF).

[0018] According to some embodiments of the present invention, the inorganic filler includes at least one selected from alumina, boehmite, aluminum hydroxide, magnesium hydroxide, graphite, and graphene.

[0019] According to some embodiments of the present invention, the silane coupling agent includes at least one of vinyltris(2-methoxyethoxy)silane, vinyltrimethoxysilane, and γ-aminopropyltriethoxysilane coupling agents.

[0020] According to some embodiments of the present invention, the weight ratio of the inorganic filler to the silane coupling agent is 1:1 to 5.

[0021] To improve the compatibility of the adhesive obtained by mixing inorganic fillers with various monomers in the safety layer, the inorganic fillers need to be modified to contain organic functional groups such as carboxyl groups, hydroxyl groups, or double bonds on their surface. The oxygen groups in the silane coupling agent have an affinity for the inorganic fillers, while the organic functional groups have an affinity for the synthesized adhesive. In other words, the silane coupling agent molecule is attracted to inorganic substances at one end and organic substances at the other end, which can form a bonding layer of organic adhesive-silane coupling agent-inorganic filler, thereby increasing compatibility.

[0022] According to some embodiments of the present invention, the particle size D of the silane coupling agent modified inorganic filler is... v 10 is 0.1–5 μm.

[0023] The inorganic filler with the above particle size is matched with the thickness of the safety layer to avoid large inorganic filler particles penetrating the safety layer and affecting the adhesion between the safety layer and the substrate.

[0024] According to some embodiments of the present invention, the release layer material includes at least one of vinyl silicone oil, hydrogen-containing silicone oil, polyvinyl alcohol, hydroxyl silicone oil, and long-chain alkyl-modified silicone oil.

[0025] According to some embodiments of the present invention, the tackifying resin includes at least one of C5 resin, hydrogenated rosin resin, and alkyd resin.

[0026] According to some embodiments of the present invention, the tackifying resin comprises a C5 resin.

[0027] The addition of tackifying resin in the formulation can reduce the impact of fillers on adhesion, maximize the content of inorganic fillers, and improve the wettability of the safety layer. Tackifying resin has a low molecular weight and high mobility, which facilitates the diffusion of the adhesive to the surface of the adhered materials. This improves the wettability of the safety layer, increases its peel strength, and promotes the bonding between the safety layer and the pressure-sensitive adhesive layer. Furthermore, it can reduce the raw material cost of the safety layer. C5 resin is a flexible resin with highly fluid chains. Due to its relatively small molecular weight, its molecular chains diffuse rapidly after contact between two materials. Mixing it with acrylic resin can alter the wettability of the composite resin material and increase its bonding strength.

[0028] The type and content of photoinitiators both affect the polymerization rate and the properties of the adhesive. If the content is too low, the polymerization reaction will not be completed and will be forced to stop because the photoinitiator is consumed. When the content of photoinitiator is too high, there may be a burst polymerization phenomenon due to the violent exothermic reaction at the beginning of the reaction. At the same time, some small molecular fragments will be formed. These fragments will migrate to the surface of the adhesive film, causing the surface of the adhesive film to yellow and reducing the aging resistance of the pressure-sensitive adhesive.

[0029] According to some embodiments of the present invention, the photoinitiator 1 and photoinitiator 2 respectively include at least one of 184 photoinitiator (1-hydroxycyclohexylphenyl ketone), TPO photoinitiator (2,4,6-trimethylbenzoyl diphenylphosphine oxide), 1173 photoinitiator (2-hydroxy-2-methyl-1-phenyl-1-propanone) and 369 photoinitiator (2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone).

[0030] The introduction of chain transfer agent 1 can significantly reduce the viscosity of the prepolymer system, facilitating subsequent coating. Without the chain transfer agent, the system viscosity is too high, making coating very difficult. When the chain transfer agent content is too high, chain transfer reactions occur before the molecular chains have a chance to polymerize, causing the polymerization reaction to terminate. In this case, the synthesized polyacrylate has a very small relative molecular mass and a very low viscosity. This not only results in a loss of the cohesive and adhesive strength of the prepolymer but also greatly affects the subsequent curing reaction of the prepolymer, and may even prevent it from curing into a film.

[0031] The safety adhesive tape of this invention comprises monomers, diluent monomers, initiators, chain transfer agents, tackifying resins, and inorganic fillers. The monomers can be categorized by function into soft monomers (acrylates), hard monomers, and functional monomers. Soft monomers have lower glass transition temperatures and provide the adhesive base for the polymer; these monomers are typically alkyl acrylates with 4-12 carbon atoms, commonly including butyl acrylate (BA) and 2-ethylhexyl acrylate (2-EHA). Hard monomers, on the other hand, have higher glass transition temperatures, which not only improve the cohesiveness of the adhesive film but also significantly enhance its transparency, adhesive strength, and water resistance.

[0032] According to some embodiments of the present invention, the pressure-sensitive adhesive layer comprises the following raw materials in parts by weight: 70-150 parts acrylate, 0.5-1 part hard monomer 2, 0.01-0.05 parts hard monomer 3, 3-10 parts functional monomer 2, 3-10 parts functional monomer 3, 0.005-0.2 parts first thermal initiator, 0.005-0.05 parts second thermal initiator, and 0.05-3 parts curing agent.

[0033] According to some preferred embodiments of the present invention, the pressure-sensitive adhesive layer comprises the following raw materials in parts by weight: 90 parts acrylate, 0.5 parts hard monomer 2, 0.02 parts hard monomer 3, 5 parts functional monomer 2, 4 parts functional monomer 3, 0.02 parts first thermal initiator, 0.01 parts second thermal initiator and 0.1 parts curing agent.

[0034] According to some embodiments of the present invention, the acrylate in the raw materials for preparing the pressure-sensitive adhesive layer includes at least one of isooctyl acrylate (2-EHA) and butyl acrylate (BA).

[0035] According to some embodiments of the present invention, the hard monomer 2 and hard monomer 3 include at least one of acrylic acid (AA), methyl methacrylate (MMA) and acrylonitrile (AN).

[0036] According to some embodiments of the present invention, the functional monomers 2 and 3 include at least one of hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), tetrahydrofuran acrylate (THFA), and N,N-dimethylacrylamide (DMF).

[0037] According to some embodiments of the present invention, the first thermal initiator includes benzoyl peroxide (BPO) or dilauryl peroxide (LPO), and the second thermal initiator includes azobisisobutyronitrile (AIBN).

[0038] According to some embodiments of the present invention, the raw materials for preparing the pressure-sensitive adhesive layer further include a curing agent.

[0039] According to some embodiments of the present invention, the curing agent of the pressure-sensitive adhesive layer includes at least one of polyisocyanate, epoxy resin and hydroxymethyl resin.

[0040] According to an embodiment of the second aspect of the present invention, a method for preparing the safety adhesive paper includes: providing a release layer on one side of the substrate layer, and sequentially stacking the safety layer and the pressure-sensitive adhesive layer on the other side of the substrate layer.

[0041] According to some preferred embodiments of the present invention, a method for preparing safety adhesive paper includes the following steps:

[0042] S1: The raw materials for preparing the safety layer are mixed and reacted to obtain a safety layer adhesive solution. The safety layer adhesive solution is then applied to one side of the substrate and cured to obtain the safety layer. A release layer is applied to the other side of the substrate.

[0043] S2: The raw materials for preparing the pressure-sensitive adhesive layer are mixed and reacted to obtain a pressure-sensitive adhesive layer solution. Then, the pressure-sensitive adhesive layer solution is applied to the surface of the safety layer and cured to obtain the pressure-sensitive adhesive layer.

[0044] According to some embodiments of the present invention, the raw materials for preparing the substrate layer include at least one of PET, BOPP and PI.

[0045] According to some embodiments of the present invention, in the step S1 of applying the safety layer adhesive to one side of the substrate, one side of the substrate is subjected to corona treatment.

[0046] Corona treatment increases the adhesion between the safety layer and the substrate.

[0047] According to some embodiments of the present invention, in step S1, the curing step includes ultraviolet light curing.

[0048] According to some embodiments of the present invention, in step S1, the UV curing time is 10 to 400 seconds.

[0049] According to some embodiments of the present invention, in step S1, the ultraviolet light energy is 50–1000 mJ / cm². 2 .

[0050] According to some embodiments of the present invention, step S2 further includes adding a curing agent to the pressure-sensitive adhesive layer liquid.

[0051] According to some embodiments of the present invention, the curing agent includes at least one of polyisocyanate, epoxy resin and hydroxymethyl resin.

[0052] According to some embodiments of the present invention, in step S2, the curing method is thermosetting.

[0053] According to some embodiments of the present invention, in step S2, the temperature of the thermosetting is 90 to 120°C.

[0054] According to some embodiments of the present invention, in step S2, the thermosetting time is 1 to 10 minutes.

[0055] According to some preferred embodiments of the present invention, the method for preparing the safety layer adhesive includes:

[0056] S1.1: Mix the inorganic filler, silane coupling agent, and solvent 1, and heat to 70-100°C. ℃ The reaction was carried out for 5–10 hours, followed by centrifugation, washing, and drying to obtain the modified inorganic filler.

[0057] S1.2: After mixing acrylate, hard monomer 1, and functional monomer 1, add photoinitiator 1 and chain transfer agent. After mixing evenly, irradiate with ultraviolet light for 5-30 seconds under nitrogen gas, and then continue stirring for 3-5 minutes. After the polymerization reaction is completed, it needs to be protected from light and wait for the glue to cool to room temperature to obtain acrylate prepolymer 1.

[0058] S1.3: Add the tackifying resin to the acrylate prepolymer 1 and continue magnetic stirring for 6 hours. Add the photoinitiator 2 and stir for 10 minutes. Then add it to S1.1 to obtain 1-80 parts by weight of the modified inorganic filler. Stir for 6 hours to obtain the safety layer adhesive.

[0059] According to some preferred embodiments of the present invention, in step S1.1, the solvent includes anhydrous ethanol.

[0060] According to some preferred embodiments of the present invention, the method for preparing the safety layer adhesive includes:

[0061] S1.1: Mix 1 part by mass of alumina, 1 to 5 parts by mass of silane coupling agent, and 15 to 25 parts by mass of anhydrous ethanol evenly, heat to 70 to 100°C, react for 5 to 10 hours, and then centrifuge, wash, and dry to obtain the modified inorganic filler.

[0062] S1.2: Mix 80-95 parts by weight of 2-ethylhexyl acrylate (2-EHA), 1-10 parts by weight of acrylic acid (AA), and 1-15 parts by weight of hydroxyethyl acrylate (HEA). Then, add 0.0005-0.005 parts by weight of photoinitiator 1 (TPO) and 0.0005-0.005 parts by weight of chain transfer agent (dodecyl mercaptan) and mix evenly to obtain a glue solution. Under nitrogen gas, irradiate with ultraviolet light for 5-30 seconds, and then continue stirring for 3-5 minutes. After the polymerization reaction is completed, it needs to be protected from light and wait for the glue solution to cool to room temperature to obtain acrylate prepolymer 1.

[0063] S1.3: Add 1-20 parts by weight of C5 resin to acrylate prepolymer 1 and continue magnetic stirring for 6 hours. Add 1 part by weight of photoinitiator 2 (184 photoinitiator), stir for 10 minutes, and then add it to S1 to obtain 1-80 parts by weight of modified inorganic filler. After stirring for 6 hours, an uncured safety layer adhesive is obtained.

[0064] The safety layer is prepared by ultraviolet light initiation and bulk polymerization to synthesize acrylate prepolymer. This method produces prepolymers with extremely high synthesis rate, high product purity, and virtually no contaminants generated during the reaction process. It also facilitates the increase of inorganic filler content.

[0065] According to some preferred embodiments of the present invention, the method for preparing the pressure-sensitive adhesive layer includes:

[0066] S2.1: Mix the first thermal initiator and solvent 2 to obtain a diluted first thermal initiator;

[0067] S2.2: Mix acrylate, functional monomer 2 and ethyl acetate, heat to 70-80℃, add diluted first thermal initiator, heat to 85-95℃, maintain the temperature and react with nitrogen gas for 5-10 minutes to obtain acrylate prepolymer 2, and cool to 60-70℃.

[0068] S2.3: Mix the first thermal initiator and ethyl acetate to obtain a diluted first thermal initiator, and add it to the mixture obtained in acrylate prepolymer 2. Maintain the temperature at 60-70℃ and react for 1-3 hours.

[0069] S2.4: Mix the second thermal initiator and ethyl acetate evenly, add them to the mixture obtained in step S2.3, heat to 70-80℃, maintain the temperature for 2-3 hours, cool to 50-60℃, and add the remaining ethyl acetate to adjust the viscosity to 1000-10000 mPa.s to obtain the pressure-sensitive adhesive layer solution.

[0070] According to some preferred embodiments of the present invention, in step S2.1, the solvent 2 includes at least one of benzene, toluene, xylene, ethyl acetate and butyl acetate.

[0071] According to some preferred embodiments of the present invention, in step S2.1, the solvent 2 includes ethyl acetate.

[0072] According to some preferred embodiments of the present invention, the method for preparing the pressure-sensitive adhesive layer includes:

[0073] S2.1: Mix 0.0025 to 0.03 parts by mass of the first thermal initiator with ethyl acetate to obtain a diluted first thermal initiator, wherein the amount of ethyl acetate is 50 to 150 times the mass of the first thermal initiator;

[0074] S2.2: Mix 20-50 parts by weight of butyl acrylate (BA), 50-100 parts by weight of 2-ethylhexyl acrylate (2-EHA), 0.5-1 parts by weight of methyl methacrylate (MMA), 0.01-0.05 parts by weight of acrylic acid (AA), 3-10 parts by weight of hydroxyethyl acrylate (HEA), 3-10 parts by weight of hydroxypropyl acrylate (HPA), and 80-135 parts by weight of ethyl acetate. Heat the mixture to 70-80°C, add a diluted first thermal initiator, and heat the mixture to 85-95°C. Maintain the temperature and purge with nitrogen for 5-10 minutes to obtain acrylate prepolymer 2. Cool the mixture to 60-70°C.

[0075] S2.3: Mix 0.05 to 0.2 parts by mass of benzoyl peroxide (BPO) and ethyl acetate at a ratio of 1:50 to 1:100 to obtain a diluted first thermal initiator, and add it to the acrylate prepolymer 2 obtained in step S2. Maintain the temperature at 60 to 70°C and react for 1 to 3 hours.

[0076] S2.4: Mix 0.01-0.05 parts by mass of the second thermal initiator azobisisobutyronitrile (AIBN) and 1-5 parts by mass of ethyl acetate, add the mixture to the mixture obtained in step S2.3, heat to 70-80°C, maintain the temperature for 2-3 hours, cool to 50-60°C, and add the remaining 10-30 parts by mass of ethyl acetate to adjust the viscosity to 1000-10000 mPa·s to obtain the pressure-sensitive adhesive layer solution.

[0077] The adhesive solution required for the pressure-sensitive adhesive layer is synthesized using solution polymerization. The solvent used is at least one of benzene, toluene, xylene, ethyl acetate, and butyl acetate. Ethyl acetate is preferred because it has a low chain transfer constant, is easily volatile, and will not remain in the adhesive layer, thus having minimal impact on its performance. The initiators typically include a primary thermal initiator with a high decomposition temperature, benzoyl peroxide (BPO) or dilauryl peroxide (LPO), and a secondary thermal initiator with a lower decomposition temperature, azobisisobutyronitrile (AIBN). The two initiators are used in combination. The primary thermal initiator, with its high decomposition temperature and good reaction controllability, is used to form the acrylate prepolymer. Further reactions utilize the secondary thermal initiator, which has a low decomposition temperature and high initiation efficiency, to improve monomer conversion and ultimately obtain a polyacrylic resin 2 with a large molecular weight and excellent adhesive properties.

[0078] According to some embodiments of the present invention, the thickness of the security layer is 1 to 10 μm.

[0079] According to some embodiments of the present invention, the thickness of the pressure-sensitive adhesive layer is 1 to 10 μm.

[0080] According to a third aspect of the present invention, a secondary battery is provided, wherein the raw materials for preparing the secondary battery include the safety adhesive paper.

[0081] The secondary battery of the present invention has good safety performance and high pass rate in thermal abuse, overcharge and high temperature short circuit tests.

[0082] According to some embodiments of the present invention, the secondary battery includes at least one of lithium-ion battery, sodium-ion battery, magnesium-ion battery, calcium-ion battery and potassium-ion battery.

[0083] According to some embodiments of the present invention, the secondary battery includes a lithium-ion battery.

[0084] According to some embodiments of the present invention, the lithium-ion battery includes a positive electrode, a negative electrode, safety tape, a separator, an electrolyte, and a casing.

[0085] According to some embodiments of the present invention, the separator separates the positive electrode and the negative electrode.

[0086] According to some embodiments of the present invention, the housing is used to house the positive electrode, the negative electrode, the separator, and the electrolyte.

[0087] According to some embodiments of the present invention, the safety adhesive tape is attached to the positive electrode tab of the lithium battery.

[0088] According to some embodiments of the present invention, the positive electrode includes a positive current collector and a positive active material layer disposed on at least one surface of the positive current collector.

[0089] According to some embodiments of the present invention, the positive electrode active material layer includes a positive electrode active material.

[0090] According to some embodiments of the present invention, the positive electrode active material includes chemical formulas such as Li a Ni x Co y M z O 2-b N b (where 0.95≤a≤1.2, x>0, y≥0, z≥0, and x+y+z=1, 0≤b≤1, M includes at least one of Mn and Al, and N includes at least one of F, P and S.)

[0091] According to some embodiments of the present invention, the positive electrode active material includes LiCoO2, LiNiO2, LiVO2, LiCrO2, LiMn2O4, LiCoMnO4, Li2NiMn3O8, and LiNi 0.5 Mn 1.5At least one of O4, LiCoPO4, LiMnPO4, LiFePO4, LiNiPO4, LiCoFSO4, CuS2, FeS2, MoS2, NiS and TiS2.

[0092] According to some embodiments of the present invention, the positive electrode active material can also be modified. Methods for modifying the positive electrode active material are known to those skilled in the art. For example, coating, doping, or other methods can be used to modify the positive electrode active material. The materials used for modification can be one or more combinations of Al, B, P, Zr, Si, Ti, Ge, Sn, Mg, Ce, and W, including but not limited to. The positive electrode current collector is typically a structure or component that collects current. The positive electrode current collector can be any material suitable for use as a positive electrode current collector in lithium-ion batteries. For example, the positive electrode current collector can be, but is not limited to, metal foil, and more specifically, aluminum foil, among others.

[0093] According to some embodiments of the present invention, the negative electrode current collector comprises a metal foil.

[0094] According to some preferred embodiments of the present invention, the negative current collector comprises copper foil.

[0095] According to some embodiments of the present invention, the electrolyte comprises an organic solvent, an electrolyte lithium salt, and additives.

[0096] According to some embodiments of the present invention, the electrolyte lithium salt includes at least one of LiPF6 and / or LiBOB, LiBF4, LiBOB, LiPF6, LiTFSI, LiClO4, LiAsF6, LiCF3SO3 and LiN(CF3SO2)2.

[0097] According to some embodiments of the present invention, the organic solvent includes at least one of cyclic carbonates, chain carbonates, and carboxylic acid esters.

[0098] According to some embodiments of the present invention, the cyclic carbonate includes at least one of PC and EC.

[0099] According to some embodiments of the present invention, the chain carbonate includes at least one of DEC, DMC and EMC.

[0100] According to some embodiments of the present invention, the carboxylic acid ester includes at least one of PP, MA, EA and EP.

[0101] According to some embodiments of the present invention, the additive includes at least one of film-forming additives, conductive additives, flame-retardant additives, overcharge prevention additives, additives for controlling the H2O and HF content in the electrolyte, additives for improving low-temperature performance, and multifunctional additives.

[0102] According to some embodiments of the present invention, the diaphragm comprises at least one selected from polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, and natural fibers.

[0103] According to some embodiments of the present invention, the material of the housing includes at least one of stainless steel and aluminum-plastic film.

[0104] According to some embodiments of the present invention, the material of the housing includes an aluminum-plastic film. Attached Figure Description

[0105] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0106] Figure 1 This is a schematic diagram of the safety adhesive tape structure in Example 1;

[0107] Figure 2 This is a schematic diagram of the positive electrode sheet with adhesive tape applied in Example 1;

[0108] Figure 3 This is a schematic diagram of the positive electrode sheet with adhesive tape applied in Example 1. Detailed Implementation

[0109] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0110] Example 1

[0111] This embodiment provides a safety adhesive tape and a battery prepared using the safety adhesive tape as a raw material. The specific steps are as follows:

[0112] (1) Preparation of safety layer adhesive:

[0113] A1: Add 1 part by mass of aluminum oxide (D v 5 parts by weight of silane coupling agent (90≤2.0μm) and 20 parts by weight of anhydrous ethanol were mixed evenly, heated to 85℃, reacted for 8h, and then centrifuged, washed and dried to obtain the modified inorganic filler.

[0114] A2: Mix 85 parts by mass of 2-ethylhexyl acrylate (2-EHA), 5 parts by mass of acrylic acid (AA), and 10 parts by mass of hydroxyethyl acrylate (HEA) solutions evenly. Then, add 0.001 parts by mass of photoinitiator 1 (TPO) and 0.001 parts by mass of chain transfer agent dodecyl mercaptan (NDM) dropwise and mix evenly. Under nitrogen gas, irradiate with ultraviolet light for 20 seconds, and then continue stirring for 3 minutes to ensure uniform reaction. After the polymerization reaction is completed, it needs to be protected from light and wait for the glue solution to cool to room temperature to obtain acrylate prepolymer 1.

[0115] A3: Then, add 5 parts by mass of C5 resin to the acrylate prepolymer 1 obtained in A2, and continue magnetic stirring for 6 hours. Add 1 part by mass of photoinitiator 2 (184 photoinitiator), stir for 10 minutes, and then add it to A1 to obtain 60 parts by mass of modified alumina. After stirring for 6 hours, an uncured safety layer adhesive is obtained.

[0116] (2) Preparation of pressure-sensitive adhesive layer solution:

[0117] B1: Mix 0.01 parts by mass of benzoyl peroxide (BPO) and ethyl acetate evenly to obtain a diluted first initiator, wherein the amount of ethyl acetate is 100 times the mass of benzoyl peroxide;

[0118] In particular, the thermal initiators involved in this invention all need to be diluted; otherwise, the reaction will be unstable, and if the temperature is too high, the resulting acrylic resin will have a low molecular weight and poor bonding performance.

[0119] B2: Mix 25 parts by weight of butyl acrylate (BA), 65 parts by weight of 2-ethylhexyl acrylate (2-EHA), 0.5 parts by weight of methyl methacrylate (MMA), 0.02 parts by weight of acrylic acid (AA), 5 parts by weight of hydroxyethyl acrylate (HEA), 4 parts by weight of hydroxypropyl acrylate (HPA), and 90 parts by weight of ethyl acetate evenly, and heat to 75°C. Add all of the diluted first thermal initiator obtained in step S1 dropwise to the mixed monomers described in S2, and heat to 92°C. Maintain the temperature and react with nitrogen gas for 8 minutes to obtain the acrylate prepolymer. Cool to 65°C.

[0120] B3: Mix the remaining 0.01 parts by mass of the first thermal initiator benzoyl peroxide (BPO) and ethyl acetate at a ratio of 1:100 to obtain a diluted first thermal initiator, and add it to the mixture obtained in step B2. Maintain the temperature at 65°C and react for 2 hours.

[0121] B4: Mix 0.01 parts by mass of the second thermal initiator azobisisobutyronitrile (AIBN) and 1 part by mass of ethyl acetate evenly, add it to the mixture obtained in step B3, heat to 75°C, maintain the temperature for 2.5 hours, cool down to 53°C, and add the remaining 20 parts by mass of ethyl acetate to adjust the viscosity to 3000-8000 mPa.s to obtain an uncured pressure-sensitive adhesive layer solution;

[0122] (3) Preparation of safety adhesive tape:

[0123] C1: The above-mentioned safety layer adhesive solution is applied to the surface of substrate 2 using a doctor blade. The substrate is PET, and one side of the substrate is corona-treated to increase the adhesion between the safety layer and the substrate. The untreated side is used to apply release layer 1 to prevent the adhesive tape from sticking. The thickness of the pressure-sensitive adhesive layer is controlled at 4 μm. The sample is then placed under a UV lamp for curing for about 300 seconds, with a light energy of approximately 800 mJ / cm². 2 Thus, a protective paper with a high content of inorganic filler 3 is obtained.

[0124] C2: Add 0.1 parts of curing agent polyisocyanate to the above pressure-sensitive adhesive layer liquid, and apply it to the surface of the aforementioned safety layer 3 containing inorganic fillers by a doctor blade. The thickness of the pressure-sensitive adhesive layer 4 is controlled at 2μm. After the pressure-sensitive adhesive layer is applied, it needs to be cured at a high temperature of 100℃ for 5 minutes to obtain a safety adhesive paper 5 with high inorganic filler content and good adhesion, with the safety layer 3 and pressure-sensitive adhesive layer 4 set separately.

[0125] (4) Preparation of negative electrode sheet:

[0126] Graphite, thickener, and styrene-butadiene rubber (SBR) were mixed evenly at a mass ratio of 97.7:1.1:1.2 to prepare a lithium-ion battery negative electrode slurry with a certain viscosity. The slurry was coated on one surface of a copper foil current collector and dried and wound up at 80°C. The negative electrode slurry was then coated and dried on the other side of the copper foil in the same way to obtain a negative electrode sheet with active material coated on both sides.

[0127] (5) Preparation of the positive electrode:

[0128] A positive electrode slurry is prepared by uniformly mixing positive electrode active material, conductive agent superconducting carbon and carbon nanotubes, and binder polyvinylidene fluoride at a mass ratio of 97.6:0.6:0.5:1.3. The positive electrode slurry is coated on one surface of current collector aluminum foil, dried and wound at 85°C, and then the positive electrode slurry is coated and dried on the other side of the aluminum foil in the same way. The positive electrode sheet with positive electrode active material layers on both sides is then cold-pressed. After that, it is trimmed, cut into sheets, and slit to produce lithium-ion battery positive electrode sheets.

[0129] (6) Preparation of electrolyte:

[0130] Lithium hexafluorophosphate (LiPF6) was dissolved in a mixed solvent of dimethyl carbonate (DMC), ethylene carbonate (EC), and ethyl methyl carbonate (EMC) in a mass ratio of 3:5:2 to obtain an electrolyte.

[0131] (7) Battery fabrication:

[0132] Safety tape 5 is attached to the lithium battery positive electrode tab position 1, the electrode material area 4 opposite the electrode tab position, the transition position between the material area and the empty foil area 6, and the end position of the roll core. Typically, the width of the safety tape material area is 2-3 mm. Figure 2 As shown ( Figure 2 This is a schematic diagram of the adhesive application process for the positive electrode (the negative electrode is similar and will not be described again). The positive and negative electrodes with the safety adhesive tape and the separator are then wound into a battery cell with a capacity of approximately 5Ah. The separator is located between adjacent positive and negative electrodes. The positive electrode is led out using aluminum tabs, and the negative electrode is led out using nickel tabs. The battery cell is then placed in an aluminum-plastic packaging bag, baked, and injected with the electrolyte described above. After encapsulation, formation, and capacity testing, a polymer lithium-ion battery is finally produced.

[0133] Figure 1 This is a schematic diagram of the structure of the safety adhesive tape 01 in this embodiment, where 011 is the release layer, 012 is the PET substrate, 013 is the safety layer, and 014 is the pressure-sensitive adhesive layer. By separating the safety layer 013 and the pressure-sensitive adhesive layer 014, the filler content in the adhesive tape can be increased while maintaining good adhesion, thereby making it easier for the battery cell to pass tests such as thermal abuse, overcharge, and high-temperature short circuit.

[0134] The application method for safety tape 01 is as follows: Figure 2 , Figure 3 As shown, safety tape 01 is attached to the tab position 021 of the positive electrode 02 of the lithium battery (the method of attaching adhesive to the negative electrode is similar and will not be described again), the electrode material area 022 opposite to the tab position, the transition position between the material area 022 and the empty foil area 023, and the core end position 024. The width of the material area of ​​the safety tape is usually 1 to 5 mm.

[0135] Example 2:

[0136] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the modified aluminum oxide in the safety layer is 20 parts by mass.

[0137] The other methods are the same as in Example 1, and will not be repeated here.

[0138] Example 3:

[0139] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the modified aluminum oxide in the safety layer is 80 parts by mass.

[0140] The other methods are the same as in Example 1, and will not be repeated here.

[0141] Example 4:

[0142] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as raw material. The difference from Embodiment 1 is that the filler content in the safety layer is 60 parts by mass, but it is changed from modified alumina to modified boehmite.

[0143] The other methods are the same as in Example 1, and will not be repeated here.

[0144] Example 5:

[0145] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the filler content in the safety layer is 60 parts by mass, but the modified aluminum oxide is changed to modified aluminum hydroxide.

[0146] The other methods are the same as in Example 1, and will not be repeated here.

[0147] Example 6:

[0148] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the tackifying resin in the preparation of the safety layer adhesive A3 is replaced with hydrogenated rosin resin instead of C5 resin.

[0149] The other methods are the same as in Example 1, and will not be repeated here.

[0150] Example 7:

[0151] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the tackifying resin in the preparation of the safety layer adhesive A3 is replaced with an alkyd resin instead of a C5 resin.

[0152] The other methods are the same as in Example 1, and will not be repeated here.

[0153] Example 8:

[0154] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that 1 part by mass of 184 photoinitiator in the preparation of safety layer adhesive solution A3 is replaced with an equal amount of 1173 photoinitiator.

[0155] The other methods are the same as in Example 1, and will not be repeated here.

[0156] Example 9:

[0157] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that 1 part by mass of 184 photoinitiator in the preparation of safety layer adhesive solution A3 is replaced with an equal amount of 369 photoinitiator.

[0158] The other methods are the same as in Example 1, and will not be repeated here.

[0159] Example 10:

[0160] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that 0.01 parts by mass of the second thermal initiator azobisisobutyronitrile (AIBN) in the preparation of pressure-sensitive adhesive layer solution B4 is replaced with an equal amount of benzoyl peroxide (BPO).

[0161] The other methods are the same as in Example 1, and will not be repeated here.

[0162] Example 11:

[0163] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the ultraviolet irradiation time in the preparation of the safety layer adhesive liquid A2 is reduced from 20s to 10s.

[0164] The other methods are the same as in Example 1, and will not be repeated here.

[0165] Example 12:

[0166] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the dilution factor of the initiator benzoyl peroxide (BPO) in the preparation of pressure-sensitive adhesive layer solution B1 is changed from 100 times to 50 times.

[0167] The other methods are the same as in Example 1, and will not be repeated here.

[0168] Example 13:

[0169] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the ultraviolet light curing time in the preparation of the safety adhesive paper C1 is shortened from 300s to 100s.

[0170] The other methods are the same as in Example 1, and will not be repeated here.

[0171] Example 14:

[0172] This embodiment provides a safety adhesive tape and a battery prepared using the safety adhesive tape as a raw material. The difference from Embodiment 1 is that the ultraviolet light curing energy in the preparation of the safety adhesive tape (C1) is changed from 800 mJ / cm². 2 Reduced to 400 mJ / cm 2 .

[0173] The other methods are the same as in Example 1, and will not be repeated here.

[0174] Example 15:

[0175] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the amount of curing agent used in the preparation of the safety adhesive paper in C2 is changed to 0.2 parts.

[0176] The other methods are the same as in Example 1, and will not be repeated here.

[0177] Example 16:

[0178] This embodiment provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Embodiment 1 is that the curing conditions in the preparation of the safety adhesive paper in C2 are changed from 100℃-5min to 90℃-5min.

[0179] The other methods are the same as in Example 1, and will not be repeated here.

[0180] Comparative Example 1:

[0181] This comparative example provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Example 1 is that the adhesive paper is coated with only a layer of pressure-sensitive adhesive with high adhesion and does not contain a safety layer.

[0182] The other methods are the same as in Example 1, and will not be repeated here.

[0183] Comparative Example 2:

[0184] This comparative example provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Example 1 is that the adhesive paper is coated with only a safety layer with a high inorganic filler content and does not contain a pressure-sensitive adhesive layer with high adhesion.

[0185] The other methods are the same as in Example 1, and will not be repeated here.

[0186] Comparative Example 3:

[0187] This comparative example provides a safety adhesive paper and a battery prepared using the safety adhesive paper as a raw material. The difference from Example 1 is that the aluminum oxide in the safety layer is 60 parts by mass, but it has not been modified.

[0188] The other methods are the same as in Example 1, and will not be repeated here.

[0189] Test Example 1

[0190] To verify the effectiveness of the safety tape, the battery's K-value, thermal abuse performance, overcharge and high-temperature short-circuit performance were tested.

[0191] Thermal abuse performance test method: According to the method specified in GB31241-2014 "Safety requirements for lithium-ion batteries and battery packs for portable electronic products", the cell is charged to 4.48V at a constant current and constant voltage of 0.7C, with a cutoff rate of 0.05C. Then, it is placed in an oven, and the oven temperature is increased to 132±2℃ at a rate of 5±2℃ / min and maintained for 60 minutes before stopping. The battery does not catch fire or explode.

[0192] K-value test: Internal short circuits are identified by the rate of battery voltage drop. The calculation formula is: K = (0CV1 - 0CV) / (0CV) 2) / 48h, where 0CV1 is the open-circuit voltage obtained by first letting the cell stand at 45℃ for 24h, then at 25℃ for 24h, and then continuing to stand at 25℃ for 48h to obtain 0CV2.

[0193] High temperature short circuit: Charge the cell to 4.45V with constant current and constant voltage at 0.7C, cutoff rate 0.02C, then put the cell into an oven at 55±5℃. When the cell surface temperature reaches 55℃±5℃, let it stand for 30 minutes. The battery will not catch fire or explode.

[0194] Overcharge: Charge at 0.2C current to 10V, and switch to constant voltage charging when the voltage reaches 10V. The battery will not catch fire or explode during this process.

[0195] The safety adhesive tapes prepared in Examples 1-16, Comparative Examples 1, 2 and 3 were applied to lithium batteries and subjected to 132°C hot box, high temperature short circuit and overcharge tests. The test results are recorded in Table 1.

[0196] Table 1. Performance Testing

[0197] Test Project K value (mV / h) 132℃ Hot Box High temperature short circuit overcharge Example 1 0.019 10 / 10 Pass 10 / 10 Pass 10 / 10 Pass Example 2 0.022 7 / 10 Pass 8 / 10 Pass 8 / 10 Pass Example 3 0.025 6 / 10 Pass 7 / 10 Pass 8 / 10 Pass Example 4 0.020 10 / 10 Pass 9 / 10 Pass 10 / 10 Pass Example 5 0.021 9 / 10 Pass 10 / 10 Pass 10 / 10 Pass Example 6 0.021 9 / 10 Pass 9 / 10 Pass 9 / 10 Pass Example 7 0.020 9 / 10 Pass 10 / 10 Pass 9 / 10 Pass Example 8 0.021 9 / 10 Pass 8 / 10 Pass 10 / 10 Pass Example 9 0.021 9 / 10 Pass 9 / 10 Pass 10 / 10 Pass Example 10 0.025 6 / 10 Pass 8 / 10 Pass 8 / 10 Pass Example 11 0.024 8 / 10 Pass 8 / 10 Pass 8 / 10 Pass Example 12 0.025 6 / 10 Pass 6 / 10 Pass 7 / 10 Pass Example 13 0.023 6 / 10 Pass 7 / 10 Pass 7 / 10 Pass Example 14 0.024 8 / 10 Pass 7 / 10 Pass 7 / 10 Pass Example 15 0.025 9 / 10 Pass 8 / 10 Pass 8 / 10 Pass Example 16 0.024 10 / 10 Pass 8 / 10 Pass 8 / 10 Pass Comparative Example 1 0.035 4 / 10 Pass 3 / 10 Pass 3 / 10 Pass Comparative Example 2 0.026 8 / 10 Pass 7 / 10 Pass 7 / 10 Pass Comparative Example 3 0.025 6 / 10 Pass 4 / 10 Pass 6 / 10 Pass

[0198] As can be seen from the table above, the K-values ​​of the battery cells prepared in Examples 1-16 are improved compared to Comparative Examples 1, 2, and 3. The pass rates of the 132℃ hot box, high-temperature short circuit, and overcharge tests are significantly higher than those of Comparative Example 1, especially Example 1, whose K-value is only 0.019mV / h, and the pass rates of all other tests are 100%. The above analysis shows that by separating the safety layer and pressure-sensitive adhesive layer in the safety adhesive paper, the content of inorganic filler in the safety layer can be increased. If the safety layer and pressure-sensitive adhesive layer are combined, the inorganic filler content generally does not exceed 20 parts by mass in order to balance a certain level of adhesion and safety. However, by separating them, adhesion can be disregarded, and the inorganic filler content can reach up to 80 parts by mass. The high content of silane coupling agent-modified inorganic filler has excellent thermal conductivity and flame retardant properties, improving the thermal runaway of the battery cell and increasing the pass rates of the battery cell's thermal abuse, overcharge, and high-temperature short circuit tests. The pressure-sensitive adhesive layer provides good adhesion, which is beneficial to the performance of the safety adhesive paper. Meanwhile, the safety tape also reduces self-discharge caused by welding burrs at the electrode tabs, thus lowering the cell's K-value. The inorganic filler content in Comparative Example 2 is the same as in Example 1, but the safety layer adhesion is poor, making it prone to wrinkling or even falling off when applying the tape, affecting its safety performance. In Comparative Example 3, the alumina was not modified, making it difficult to disperse the inorganic filler evenly, resulting in poorer thermal conductivity and worse cell performance in 132°C hot box, high-temperature short circuit, and overcharge tests.

[0199] The foregoing description of specific exemplary embodiments of the present invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and those skilled in the art can make various corresponding changes and modifications based on the above technical solutions and concepts. The exemplary embodiments were chosen and described to reveal the specific principles and practical applications of the invention, thereby enabling those skilled in the art to implement and utilize various different exemplary experimental schemes and various choices and modifications of the invention. All such changes and modifications are defined by the claims and their equivalents.

Claims

1. A security tape, characterized in that It includes a release layer, a substrate layer, a safety layer, and a pressure-sensitive adhesive layer, which are stacked sequentially from top to bottom; The raw materials for preparing the safety layer include inorganic fillers modified with silane coupling agents; The raw materials for preparing the silane coupling agent modified inorganic filler include silane coupling agent and inorganic filler; The raw materials for preparing the pressure-sensitive adhesive layer are the following components in parts by weight: 70-150 parts acrylate, 0.5-1 part hard monomer 2, 0.01-0.05 parts hard monomer 3, 3-10 parts functional monomer 2, 3-10 parts functional monomer 3, 0.005-0.2 parts first thermal initiator, 0.005-0.05 parts second thermal initiator, and 0.05-3 parts curing agent; The safety layer comprises the following raw materials in parts by weight: 80-95% acrylate, 1-10 parts hard monomer 1, 1-15 parts functional monomer 1, 20-80 parts silane coupling agent modified inorganic filler, 1-20 parts tackifying resin, 0.0005-0.005 parts photoinitiator 1, 0.5-5 parts photoinitiator 2, and 0.0005-0.005 parts chain transfer agent 1; The photoinitiator 1 and photoinitiator 2 respectively include at least one of the following: 184 photoinitiator (1-hydroxycyclohexylphenyl ketone), TPO photoinitiator (2,4,6-trimethylbenzoyl diphenylphosphine oxide), 1173 photoinitiator (2-hydroxy-2-methyl-1-phenyl-1-propanone), and 369 photoinitiator (2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone); The tackifying resin includes at least one of C5 resin, hydrogenated rosin resin, and alkyd resin; The safety adhesive paper includes safety adhesive paper prepared by the following method: S1: The raw materials for preparing the safety layer are mixed and reacted to obtain a safety layer adhesive solution. The safety layer adhesive solution is then applied to one side of the substrate and cured to obtain the safety layer. A release layer is applied to the other side of the substrate. S2: The raw materials for preparing the pressure-sensitive adhesive layer are mixed and reacted to obtain a pressure-sensitive adhesive layer solution. Then, the pressure-sensitive adhesive layer solution is applied to the surface of the safety layer and cured to obtain the pressure-sensitive adhesive layer. In step S1, the curing step includes ultraviolet light curing; in step S2, the curing method is thermal curing.

2. The security gummed paper according to claim 1, wherein The inorganic filler includes at least one of alumina, boehmite, aluminum hydroxide, magnesium hydroxide, graphite, and graphene; the silane coupling agent includes at least one of vinyltris(2-methoxyethoxy)silane, vinyltrimethoxysilane, and γ-aminopropyltriethoxysilane coupling agent.

3. The security gummed paper according to claim 2, wherein The particle size D of the silane coupling agent-modified inorganic filler is 0.1 to 5 μm. v 10 is 0.1 to 5 μm.

4. The security gummed paper according to claim 1, wherein The acrylates include at least one of isooctyl acrylate (2-EHA) and butyl acrylate (BA).

5. The safety adhesive tape according to claim 4, characterized in that, The hard monomers 1, 2 and 3 respectively include at least one of acrylic acid (AA), methyl methacrylate (MMA) and acrylonitrile (AN).

6. The safety adhesive tape according to claim 4, characterized in that, The functional monomers 1, 2 and 3 respectively include at least one of hydroxyethyl acrylate (HEA), hydroxypropyl acrylate (HPA), tetrahydrofuran acrylate (THFA) and N,N-dimethylacrylamide (DMF).

7. The safety adhesive tape according to claim 1, characterized in that, The thickness of the security layer is 1~10μm.

8. The safety adhesive tape according to claim 1, characterized in that, The thickness of the pressure-sensitive adhesive layer is 1~10μm.

9. A method for preparing safety adhesive paper as described in any one of claims 1 to 8, characterized in that, The method for preparing the safety adhesive paper includes: providing a release layer on one side of the substrate layer, and sequentially stacking the safety layer and the pressure-sensitive adhesive layer on the other side of the substrate layer.

10. A secondary battery, characterized in that, The secondary battery includes the safety adhesive tape as described in any one of claims 1 to 8.

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