Method for manufacturing puncture-resistant electrode-coated film material, method for manufacturing nickel electrode, and nickel-based battery

Abstract

This disclosure provides a method for preparing a puncture-resistant edge-sealing membrane, a method for preparing a nickel electrode, and a nickel-based battery. The method for preparing the puncture-resistant edge-sealing membrane includes the following steps: surface activation treatment of a polyolefin membrane substrate; mixing fiber reinforcing material, surface adhesive monomer, crosslinking agent, and photoinitiator in an ethanol solvent to obtain a coating liquid; coating the coating liquid onto the surface of the activated substrate to obtain a coating intermediate; and ultraviolet curing the coating intermediate to form a puncture-resistant coating to obtain the puncture-resistant edge-sealing membrane. The rigid network formed by the crosslinking of the surface adhesive monomer and the fiber reinforcing material improves mechanical strength and puncture resistance, eliminating the safety hazard of internal short circuits. The surface adhesive monomer, after ultraviolet curing, forms a grafted polymer that absorbs the electrolyte, and the resulting gel layer has ionic conductivity, allowing the coated portion to participate in the electrochemical reaction and reducing battery capacity loss.

Description

Technical Field

[0001] This disclosure relates to the technical field of battery manufacturing, and in particular to a method for preparing a puncture-resistant electrode edge-wrapping film, a method for preparing a nickel electrode, and a nickel-based battery. Background Technology

[0002] Nickel-metal hydride (NiMH) batteries are widely used in energy storage systems and consumer electronics due to their high safety, long cycle life, and good environmental adaptability. In the manufacturing process of NiMH batteries, the positive electrode typically uses nickel foam as the current collector, which is then filled with active material to form the electrode, thereby providing a high specific surface area and a good electron transport path.

[0003] During the processing and molding of nickel foam, the edges of its microporous structure develop burrs resembling metallic wires. These burrs are tiny, irregular in shape, and highly hard. During battery winding or stacking assembly, and subsequent charge-discharge cycles, they may puncture the separator, causing a short circuit between the positive and negative electrodes and posing a safety hazard. Currently, masking tape is used to protect the edges of the positive electrode. Masking tape has a certain mechanical strength and flexibility, which can physically isolate the metallic burrs from the separator, thus preventing puncture to some extent. However, as an insulating material, the masking tape completely blocks electrolyte wetting and ion transport in the covered area, preventing some of the positive electrode active material from participating in the electrochemical reaction, resulting in capacity loss in the covered area.

[0004] For example, prior art document CN202423310585.5 discloses a nickel-metal hydride battery positive electrode and battery. The nickel-metal hydride battery positive electrode includes: a substrate, an active material region formed on the substrate, and a mesh buffer zone located on one side of the active material region. A tab is welded to the mesh buffer zone, and an insulating layer is attached to the tab. The insulating layer covers at least a portion of the inner edge of the tab and at least a portion of the mesh buffer zone in the width direction, which can improve the stability of the battery. However, in this design, after the insulating layer covers the electrode, the active material in the covered portion cannot participate in the electrochemical reaction, resulting in a loss of capacity in the covered portion and reducing the overall energy density of the battery. Summary of the Invention

[0005] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a method for preparing a puncture-resistant electrode edge-wrapping film with improved puncture resistance and ionic conductivity, a method for preparing a nickel electrode, and a nickel-based battery.

[0006] The purpose of this disclosure is achieved through the following technical solution: A method for preparing a puncture-resistant edge-sealing membrane material includes the following steps: A surface activation treatment is performed on a polyolefin membrane substrate to obtain an activated substrate; wherein the polyolefin membrane substrate is a microporous polyolefin membrane. A coating solution is obtained by mixing fiber-reinforcing material, a mixture of surface adhesive monomers, a crosslinking agent, and a photoinitiator in an ethanol solvent; wherein the surface adhesive monomer mixture includes acrylate monomers and at least one monomer selected from those containing carboxyl groups and those containing anhydride groups. The coating liquid is applied to the surface of the activated substrate to form a coating layer, thereby obtaining a coating intermediate. The coating intermediate is subjected to ultraviolet curing to induce polymerization and cross-linking reactions in the surface adhesive monomers in the coating layer, and to form a puncture-resistant coating together with the fiber reinforcement material to obtain a puncture-resistant edge-sealing membrane material.

[0007] In one embodiment, the coating liquid comprises the following components by mass: 50-70 parts fiber-reinforced material; 25-35 parts of surface-adhesive monomer; Crosslinking agent 2-6 parts; Photoinitiator 0.5-2 parts; 200-300 parts of ethanol solvent.

[0008] In one embodiment, the acrylate monomer includes at least one selected from ethyl acrylate, butyl acrylate, and isooctyl acrylate; and / or, The carboxyl-containing monomer includes at least one selected from acrylic acid, itaconic acid, and methacrylic acid; and / or, The monomer containing anhydride groups includes at least one of maleic anhydride, itaconic anhydride, and acrylic anhydride; and / or, The crosslinking agent includes at least one of polydipentaerythritol pentaacrylate and ethoxylated trimethylolpropane triacrylate.

[0009] In one embodiment, the microporous polyolefin membrane is at least one of a microporous polyethylene membrane or a microporous polypropylene membrane.

[0010] In one embodiment, the elongation of the microporous polyolefin membrane is 15%-20%, and the tensile strength of the microporous polyolefin membrane is 2000N / m-2500N / m.

[0011] In one embodiment, the fiber reinforcement material is at least one selected from polyimide fiber, para-aramid fiber, meta-aramid fiber, and polyacrylonitrile fiber.

[0012] In one embodiment, when the coating intermediate is UV-cured, the UV wavelength for photocuring is 350nm-400nm, and the UV light intensity is 10mW / cm². 2 -50mW / cm 2 The exposure time for ultraviolet rays is 10s-60s.

[0013] A method for preparing a nickel electrode includes the following steps: The puncture-resistant edge-sealing membrane material is prepared by the preparation method of the puncture-resistant edge-sealing membrane material described in any of the above embodiments. A positive electrode current collector is obtained by coating the positive electrode material onto the current collector and drying it. The positive electrode current collector is rolled by a rolling equipment and the floating powder on the surface of the positive electrode current collector is blown away to obtain a positive electrode intermediate. The puncture-resistant edge-sealing film is attached to the edges of both sides of the positive electrode intermediate to obtain a nickel positive electrode.

[0014] In one embodiment, the thickness of the puncture-resistant edge-sealing membrane is 60 μm to 120 μm.

[0015] A nickel-based battery includes a nickel electrode, a separator, and a negative electrode as described in any of the above embodiments, wherein the nickel electrode, the separator, and the negative electrode are stacked sequentially.

[0016] Compared with the prior art, this disclosure has at least the following advantages: The aforementioned method for preparing the puncture-resistant edge-sealing membrane material improves the mechanical strength and puncture resistance of the membrane layer by forming a cross-linked rigid network on the surface of the microporous polyolefin membrane with fiber reinforcement materials and surface adhesive monomers. After the puncture-resistant edge-sealing membrane material is wrapped around the edge of the foamed nickel positive electrode sheet, it effectively isolates the metal filament protrusions, preventing them from puncturing the separator and thus eliminating the safety hazard of internal short circuits caused by burrs. The acrylate components in the surface adhesive monomers provide initial adhesion properties, and after UV curing, they form strong chemical bonds or strong physical adsorption with the surface-activated microporous polyolefin membrane substrate. Under the action of cross-linking agents and photoinitiators, the monomers undergo cross-linking... The grafted polymer, formed by the polymerization and cross-linking reaction, has a three-dimensional network structure, which improves the peel strength of the puncture-resistant coating and its stability in the electrolyte. Monomers containing carboxyl groups or anhydride groups increase the adsorption capacity of the puncture-resistant coating for the electrolyte, enabling the three-dimensional cross-linked polymer network to fully absorb and bind electrolyte molecules, thereby forming a stable polymer electrolyte gel layer. The gel layer has good ionic conductivity and provides ion transport channels for the active material in the edge region of the foam positive electrode, allowing the coated part to participate in the electrochemical reaction, thereby reducing the loss of battery capacity and improving the overall energy density of the battery. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart illustrating the steps of a method for preparing a puncture-resistant edge-sealing membrane material according to one embodiment; Figure 2 This is a flowchart illustrating the steps of a method for preparing a nickel electrode according to one embodiment. Detailed Implementation

[0019] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0020] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments: Please refer to the following method for preparing a puncture-resistant edge-sealing membrane according to an embodiment of the present invention, which includes the following steps: S101, The polyolefin membrane substrate is subjected to surface activation treatment to obtain an activated substrate; wherein, the polyolefin membrane substrate is a microporous polyolefin membrane. S103, fiber reinforcement material, surface adhesive monomer mixture, crosslinking agent and photoinitiator are added to ethanol solvent and mixed to obtain coating liquid; wherein, the surface adhesive monomer mixture includes acrylate monomers and at least one monomer selected from carboxyl-containing monomers and anhydride-containing monomers.

[0023] S105, the coating liquid is applied to the surface of the activated substrate to form a coating layer, thereby obtaining a coating intermediate; S107, the coating intermediate is UV cured to induce polymerization and crosslinking reactions in the surface adhesive monomer, and together with the fiber reinforcement material, a puncture-resistant coating is formed to obtain a puncture-resistant edge-sealing membrane.

[0024] Understandably, after surface activation treatment, polar functional groups are introduced into the surface of the polyolefin film substrate, forming chemical bonds or strong physical adsorption with the active monomers in the coating solution. After curing, the puncture-resistant coating is not easy to fall off, ensuring the integrity of the edge-sealing film layer during electrode processing and battery charging and discharging.

[0025] It is understandable that the crosslinking agent causes acrylate monomers and at least one monomer selected from carboxyl-containing monomers and anhydride-containing monomers to crosslink and form an effective three-dimensional network of graft polymers. The acrylates, carboxyl-containing or anhydride-containing polar groups in the graft polymers absorb and bind electrolyte molecules, thereby forming a stable polymer electrolyte gel layer inside the crosslinked network. This results in a high conductivity of the gel layer, which in turn allows the active substances in the coated edge regions to obtain ion transport channels and partially participate in the electrochemical reaction.

[0026] Understandably, after UV curing, the fiber-reinforced material forms a composite puncture-resistant coating with a cross-linked polymer network. The rigid fiber-reinforced material is uniformly dispersed in the coating to act as stress-bearing points. When subjected to the puncture force of a nickel foam burr, the rigid fiber-reinforced material resists deformation through its high modulus and absorbs energy through mechanisms such as interfacial debonding, fiber pull-out, or crack deflection, thereby improving the puncture resistance of the composite puncture-resistant coating.

[0027] The aforementioned method for preparing the puncture-resistant edge-sealing membrane material improves the mechanical strength and puncture resistance of the membrane layer by forming a cross-linked rigid network on the surface of the microporous polyolefin membrane with fiber reinforcement materials and surface adhesive monomers. After the puncture-resistant edge-sealing membrane material is wrapped around the edge of the foamed nickel positive electrode sheet, it effectively isolates the metal filament protrusions, preventing them from puncturing the separator and thus eliminating the safety hazard of internal short circuits caused by burrs. The acrylate components in the surface adhesive monomers provide initial adhesion properties, and after UV curing, they form strong chemical bonds or strong physical adsorption with the surface-activated microporous polyolefin membrane substrate. Under the action of cross-linking agents and photoinitiators, the monomers undergo cross-linking... The grafted polymer, formed by the polymerization and cross-linking reaction, has a three-dimensional network structure, which improves the peel strength of the puncture-resistant coating and its stability in the electrolyte. Monomers containing carboxyl groups or anhydride groups increase the adsorption capacity of the puncture-resistant coating for the electrolyte, enabling the three-dimensional cross-linked polymer network to fully absorb and bind electrolyte molecules, thereby forming a stable polymer electrolyte gel layer. The gel layer has good ionic conductivity and provides ion transport channels for the active material in the edge region of the foam positive electrode, allowing the coated part to participate in the electrochemical reaction, thereby reducing the loss of battery capacity and improving the overall energy density of the battery.

[0028] In one embodiment, the coating liquid comprises the following components by mass: 50-70 parts fiber-reinforced material; 25-35 parts of surface-adhesive monomer; Crosslinking agent 2-6 parts; Photoinitiator 0.5-2 parts; 200-300 parts of ethanol solvent.

[0029] In this embodiment, when the content of fiber reinforcing material is less than 50 parts, the cross-linking density of the three-dimensional cross-linked network formed after UV curing is insufficient, which reduces the puncture resistance of the composite film and makes it difficult to effectively block the metal burrs on the edge of the nickel foam. When the content of fiber reinforcing material is greater than 70 parts, the viscosity of the coating liquid is too high, making it difficult to coat the microporous membrane surface and pores evenly. Moreover, the coating is too rigid after curing and loses its flexibility, which leads to cracking when the electrode is wound. When the content of fiber reinforcing material is 50-70 parts, the coating maintains sufficient puncture resistance while having appropriate flexibility and is matched with the microporous polyolefin membrane substrate with an elongation of 15%-20%.

[0030] Understandably, when the content of surface viscous monomers is less than 25 parts, the number of grafted polymers formed by the cross-linking reaction is insufficient, making it impossible for the grafted polymers to form a continuous and stable gel layer after interacting with the electrolyte. This results in obstructed ion transport in the covered area and an insignificant capacity recovery effect. When the content of surface viscous monomers is higher than 35 parts, the excessive polar groups will cause the coating to be overly hydrophilic, resulting in an excessive swelling rate in the electrolyte. This will reduce the mechanical strength of the gel layer and weaken the overall puncture resistance. When the content of surface viscous monomers is between 25 and 35 parts, the coating layer absorbs an appropriate amount of electrolyte after curing to form a stable gel and avoids excessive swelling, thus achieving a balance between ionic conductivity and mechanical stability.

[0031] Understandably, the photoinitiator content is 0.5-2 parts, ensuring a thorough and uniform polymerization reaction under UV irradiation, reducing photoinitiator residue, and balancing curing efficiency with electrochemical compatibility. Ethanol solvent is used to achieve efficient UV curing while avoiding residue; as a volatile solvent with a boiling point of 78°C, ethanol dries quickly after coating. A dosage of 200-300 parts ethanol solvent results in a moderate viscosity of the coating solution (5-50 cP), allowing for uniform spreading of the coating solution on the microporous membrane surface and preventing excessive penetration into the micropores that could clog ion channels. If the ethanol solvent content is less than 200 parts, the coating solution is too thick, making it difficult to form a thin and uniform coating; if the ethanol solvent content is greater than 300 parts, the coating solution concentration is too low, leading to a decrease in the puncture resistance of the coating layer. Specifically, the photoinitiator is at least one of 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0032] In one embodiment, the acrylate monomer includes at least one of ethyl acrylate, butyl acrylate, and isooctyl acrylate; and / or, the carboxyl-containing monomer includes at least one of acrylic acid, itaconic acid, and methacrylic acid; and / or, the anhydride-containing monomer includes at least one of maleic anhydride, itaconic anhydride, and acrylic anhydride; and / or, the crosslinking agent includes at least one of polydipentaerythritol pentaacrylate and ethoxylated trimethylolpropane triacrylate. In this embodiment, ethyl acrylate, butyl acrylate, and isooctyl acrylate provide ester groups, acrylic acid provides carboxyl groups, itaconic acid, and methacrylic acid, and maleic anhydride, itaconic anhydride, and acrylic anhydride provide anhydride groups. The groups of the surface adhesive monomer can absorb and bind the electrolyte to form a stable gel polymer electrolyte layer. The carboxyl groups and anhydride groups chemically bond with the hydroxyl groups introduced after activation treatment on the surface of the microporous polyolefin membrane, and form coordination bonds with the metal oxides at the edge of the foamed nickel electrode, thereby improving the bonding strength between the edge-sealing film layer and the substrate and the electrode. The crosslinking agents dipentaerythritol pentaacrylate and ethoxylated trimethylolpropane triacrylate are used to improve the crosslinking density and hardness of the puncture-resistant coating.

[0033] Understandably, in a strongly alkaline electrolyte, the three-dimensional fully cross-linked network structure formed by the curing of acrylate monomers and at least one monomer component selected from those containing carboxyl groups and those containing anhydride groups under ultraviolet light exhibits significantly inhibited hydrolysis of ester bonds due to steric hindrance. A small amount of side chain hydrolysis is converted into potassium carboxylate, thus maintaining the integrity of the main cross-linked backbone of the puncture-resistant coating and ensuring its alkali resistance. Understandably, this is to improve the stability of the puncture-resistant coating in alkaline electrolytes. Further, in one embodiment, the acrylate monomers account for 5%-15% of the total mass of the surface-adhesive monomers. In this embodiment, when the acrylate monomer content accounts for 5%-15% of the total mass of the surface-adhesive monomers, the ester bond content is low, and combined with the high crosslinking density, the gel layer exhibits better stability in alkaline electrolytes.

[0034] Furthermore, in one embodiment, after mixing the fiber reinforcement material, the surface adhesive monomer containing polar groups, the crosslinking agent, and the photoinitiator in an ethanol solvent to obtain a coating solution, the following step is further included before coating the coating solution onto the surface of the activated substrate to form a coating layer: A linear polymer additive, comprising 5%-20% by weight of the surface tack monomer, is added to the coating solution. The linear polymer additive is at least one of poly(N-vinylpyrrolidone) and polyacrylamide. In this embodiment, the linear polymer forms a physical entanglement with the cross-linked acrylate, carboxyl, or anhydride network, creating a more stable semi-interpenetrating polymer network. This inhibits excessive swelling of the gel layer in the electrolyte, improves the stability of the gel layer in alkaline electrolytes, and enhances puncture resistance and tear resistance. The amide or lactam groups synergistically absorb the electrolyte with the surface tack monomer, thereby forming a gel layer with high ionic conductivity. Poly(N-vinylpyrrolidone) and polyacrylamide increase the viscosity of the coating solution, prevent fiber sedimentation, and ensure uniform coating thickness.

[0035] Furthermore, in one embodiment, after UV curing the coating intermediate to induce polymerization and crosslinking reactions in the fiber reinforcement material of the coating layer to obtain a puncture-resistant edge-sealing membrane, the following steps are further included: The UV-cured puncture-resistant edge-sealing membrane is heated at 80℃-120℃ and under vacuum for 1h-4h to form a semi-interpenetrating structure between the linear polymer and the cross-linked network. In this embodiment, heating curing increases the crosslinking density of the crosslinking network between the linear polymer and the surface adhesive monomer, reducing the dissolution rate of the gel layer in the electrolyte. During UV curing, the inconsistent shrinkage rates of the coating surface and interior generate internal stress. Heating treatment relaxes the polymer chains, releasing the internal stress, improving the film smoothness, and making the adhesion to the substrate tighter, reducing the risk of local peeling or puncture due to stress concentration. After UV curing, a small amount of unreacted acrylate double bonds, carboxyl groups, or anhydride groups remain. Under heating conditions, these residual groups undergo thermally initiated polymerization, esterification, or amidation reactions, forming additional chemical crosslinking points, further enhancing the mechanical strength and alkali resistance of the gel layer. Heating under vacuum removes residual ethanol solvent, photoinitiator decomposition products, and other low-molecular-weight impurities, preventing impurities from migrating into the electrolyte after battery filling. By introducing vacuum thermal annealing after UV curing, the semi-interpenetrating network is stabilized, improving the mechanical properties, dimensional stability, and long-term reliability of the puncture-resistant edge-sealing film in alkaline electrolytes.

[0036] In one embodiment, the microporous polyolefin membrane is at least one of a microporous polyethylene membrane or a microporous polypropylene membrane. In this embodiment, both the microporous polyethylene membrane and the microporous polypropylene membrane are non-polar polyolefin materials, which do not swell, hydrolyze, or degrade in the strongly alkaline electrolyte of nickel-based batteries, thus maintaining dimensional stability and mechanical properties over a long period of time. The microporous polyethylene membrane and the microporous polypropylene membrane have certain tensile strength and puncture resistance, forming a composite structure with the surface cross-linked puncture-resistant coating, thereby improving the physical isolation effect on the edge burrs of the nickel foam. The microporous structure retains ion transport channels, and the gel layer formed by the grafted polymer provides ion supply, effectively reducing capacity loss and avoiding increased local polarization caused by pore blockage.

[0037] In one embodiment, the elongation of the microporous polyolefin membrane is 15%-20%, and the tensile strength of the microporous polyolefin membrane is 2000N / m-2500N / m. In this embodiment, the elongation of the microporous polyolefin film is 15%-20%, ensuring sufficient deformation force during battery electrode winding and bending, preventing excessive stretching of the edge-wrapping film layer under stress due to excessive elongation. The UV-cured puncture-resistant coating itself is rigid. When the tensile strength of the microporous polyolefin film is less than 2000 N / m, the microporous polyolefin film substrate yields first under stress, causing the coating to crack locally due to loss of support. When the tensile strength is greater than 2500 N / m, the flexibility of the microporous polyolefin film substrate decreases significantly, and the elongation simultaneously drops below 15%. This leads to brittle fracture of the microporous polyolefin film layer due to insufficient elastic deformation capacity during electrode winding or battery charge / discharge volume expansion. Furthermore, excessively high tensile strength tends to saturate the marginal contribution to improving puncture resistance, increasing material costs and processing difficulty. The tensile strength is 2000 N / m-2500 N / m. N / m increases the resistance to puncture stress from the filamentous protrusions of the nickel foam, thereby maintaining material isolation from the burrs at the edge of the nickel foam and ensuring the integrity and reliability of the cladding film during manufacturing and application.

[0038] In one embodiment, the fiber reinforcement material is at least one selected from polyimide fiber, para-aramid fiber, meta-aramid fiber, and polyacrylonitrile fiber. In this embodiment, the imide fiber, para-aramid fiber, meta-aramid fiber, and polyacrylonitrile fiber are all high-modulus and high-strength materials. After the fiber reinforcement material is introduced into the coating layer, it forms a rigid reinforcing phase in the UV-cured cross-linked network, which significantly improves the puncture resistance of the composite film layer, thereby effectively resisting the puncture force of the metal wire-like protrusions at the edge of the nickel foam. The puncture-resistant functional component is dispersed in the coating layer in the form of fibers or particles, avoiding blockage of the ion channels of the microporous polyolefin membrane. The gel layer of the surface adhesive monomer can still provide an ion conduction pathway, ensuring that the active substances in the covered area can participate in the electrochemical reaction. The polyimide fiber has good hydrolysis resistance in concentrated alkali. The amide bonds of para-aramid and meta-aramid are stable in alkaline environments and do not degrade. The polyacrylonitrile fiber has good alkali resistance.

[0039] In one embodiment, the aspect ratio of the fibrous rigid reinforcing material is between 20:1 and 200:1. In this embodiment, when the aspect ratio of the fibrous rigid reinforcing material is less than 20:1, the fibers are too short, the reinforcing effect is close to that of particles, and it is difficult to exert the bridging and pull-out toughening mechanism of the fibers, resulting in limited improvement in puncture resistance. When the aspect ratio of the fibrous rigid reinforcing material is greater than 200:1, the fibers are too long and are prone to entanglement and aggregation, making them difficult to disperse in the coating liquid. Local overlaps are also prone to forming large-sized aggregates, which can become stress concentration points or block microporous ion channels. When the aspect ratio of the fibrous rigid reinforcing material is between 20:1 and 200:1, the fibers are well dispersed in the coating liquid and provide toughening and crack-inhibiting effects, thereby improving the puncture resistance of the puncture-resistant edge-sealing membrane.

[0040] In one embodiment, when the coating intermediate is UV-cured, the UV wavelength is 350nm-400nm and the UV light intensity is 0.5mW / cm². 2 -50mW / cm 2 The exposure time of the ultraviolet light is 10s-60s. In this embodiment, the wavelength of the photocurable ultraviolet light is 350nm-400nm, which can be efficiently absorbed by the photoinitiator, thereby generating sufficient free radicals to ensure the full polymerization and crosslinking reactions of monomers such as acrylates, acrylamides, or NVP; when the ultraviolet light intensity is 0.5mW / cm², the UV light exposure time is 10s-60s. 2 -50mW / cm 2 This process ensures uniform cross-linking between the inner and outer surfaces of the coating, and reduces cracks and internal stress. The exposure time is 10s-60s, which can be adjusted by the composition of the coating liquid, the coating thickness, and the light intensity.

[0041] Furthermore, in one embodiment, the coating intermediate is UV-cured to induce polymerization and crosslinking reactions in the surface adhesive monomers of the coating layer, and to form a puncture-resistant coating together with the fiber reinforcement material to obtain a puncture-resistant edge-sealing membrane material, further comprising the following steps: First, at 0.5mW / cm 2 -1mW / cm 2 Pre-curing is performed by irradiating with low light intensity for 30-60 seconds; In this embodiment, if high light intensity is directly used to cure the coating intermediate in one step, the surface layer of the coating will polymerize and shrink quickly, while the bottom layer will polymerize more slowly, which will easily lead to a mismatch in volume shrinkage, resulting in the accumulation of internal stress and thus causing microcracks or film warping. By first using low light intensity pre-curing, the coating layer can be slowly polymerized to initially form a cross-linked network and release some shrinkage stress. Then, high light intensity is used for main curing to allow the residual monomers to fully react, thereby achieving complete cross-linking. Gradient curing can reduce internal stress and thus improve the smoothness of the film.

[0042] Further, in one embodiment, the surface activation treatment is at least one of low-temperature plasma treatment or corona treatment. In this embodiment, the surface of the microporous polyolefin film is activated by low-temperature plasma or corona treatment. While maintaining the mechanical properties of the activated substrate, polar functional groups such as hydroxyl, carbonyl, and carboxyl groups are introduced into the surface to increase the surface energy, thereby improving the wettability and spreading uniformity of the coating liquid, and enhancing the chemical bonding and physical anchoring between the UV-cured coating and the substrate. Specifically, when using low-temperature plasma treatment to activate the surface of the activated substrate, the working gas for the low-temperature plasma treatment is argon, the pressure is 10Pa-100Pa, the radio frequency power is 100W-500W, and the treatment time is 1s-10s. Understandably, under argon plasma bombardment, the CH bonds on the surface of the polyolefin film are broken, forming polar groups such as hydroxyl, carboxyl, and carbonyl groups; the low-pressure environment of 10Pa-100Pa ensures a moderate plasma density, effectively etching the surface inert layer and avoiding excessive damage to the substrate; the RF power of 100W-500W and the processing time of 1s-10s provide sufficient ion energy to activate the surface reaction and achieve high processing efficiency, making it suitable for continuous production.

[0043] like Figure 2 As shown, this application also provides a method for preparing a nickel electrode, comprising the following steps: The active puncture-resistant edge-sealing membrane material is prepared by the preparation method of the puncture-resistant edge-sealing membrane material described in any of the above embodiments. A positive electrode current collector is obtained by coating the positive electrode material onto the current collector and drying it. The positive electrode current collector is rolled by a rolling mill and the floating powder on the surface of the positive electrode current collector is blown off to obtain a positive electrode intermediate. The puncture-resistant edge-sealing film is attached to the edges of both sides of the positive electrode intermediate to obtain a nickel positive electrode.

[0044] In this embodiment, a puncture-resistant edge-sealing film is attached to both edges of the positive electrode intermediate. This film possesses excellent puncture resistance and flexibility, tightly covering the filamentous protrusions of the nickel foam in the current collector. During subsequent coating of the positive electrode material and battery assembly, it effectively isolates the protrusions of the nickel foam from the separator, preventing short-circuit faults caused by the protrusions piercing the separator. Furthermore, because the surface-adhesive monomers in the puncture-resistant edge-sealing film form a gel layer with high ionic conductivity in the electrolyte, the nickel foam in the covered edge area can still conduct ions, thereby improving the battery energy density. This application is not only applicable to nickel foam current collectors but also to other porous metal current collectors with edge burr problems, and corresponding alkaline or organic electrolyte battery systems.

[0045] Furthermore, in one embodiment, after attaching the puncture-resistant edge-sealing film to the edges of both sides of the positive electrode intermediate to obtain a nickel positive electrode, the following steps are further included: The nickel cathode is rolled at a pressure of 0.3 MPa-0.8 MPa and a temperature of 20°C-60°C. In this embodiment, rolling increases the bonding strength between the anti-puncture edge film and the cathode intermediate and improves the flatness of the nickel cathode surface. When the pressure is below 0.3 MPa, the edge film layer is not tightly bonded to the edge of the nickel foam, which can easily lead to edge lifting or detachment in subsequent processes. When the pressure is above 0.8 MPa, excessive compression of the nickel foam can easily cause deformation or breakage of the edge film layer. The temperature is controlled at 20°C-60°C to provide flexibility and adhesion to the film layer through heating.

[0046] In one embodiment, the thickness of the puncture-resistant edge-sealing membrane is 60 μm to 120 μm. In this embodiment, the thickness of the puncture-resistant edge-sealing membrane is 60 μm to 120 μm, providing a mechanical barrier against puncture while maintaining the flexibility of the puncture-resistant edge-sealing membrane; and when the thickness of the puncture-resistant edge-sealing membrane is within this range, the puncture-resistant edge-sealing membrane can fully absorb the electrolyte and form a gel layer with continuous ion-conducting channels, and ultraviolet light curing can penetrate the entire puncture-resistant coating, allowing the puncture-resistant coating to be fully cross-linked and cured.

[0047] This application also provides a nickel-based battery, including a nickel electrode, a separator, and a negative electrode as described in any of the above embodiments, wherein the nickel electrode, separator, and negative electrode are stacked sequentially. In this embodiment, the edge of the nickel electrode is covered with a puncture-resistant edge-sealing film layer, which improves puncture resistance and flexibility, thereby effectively isolating the filamentous protrusions of the foamed nickel. During battery assembly, formation, and long-term cycling, puncture or wear marks are avoided when the separator contacts the edge of the positive electrode, preventing short circuits and thus improving battery production yield and safety. The gel layer in the puncture-resistant edge-sealing film layer forms a stable ion-conducting channel in the alkaline electrolyte, allowing the active material in the covered edge area to partially participate in the electrochemical reaction, thereby reducing capacity loss caused by tape edge sealing.

[0048] Compared with the prior art, this disclosure has at least the following advantages: The aforementioned method for preparing the puncture-resistant edge-sealing membrane material improves the mechanical strength and puncture resistance of the membrane layer by forming a cross-linked rigid network on the surface of the microporous polyolefin membrane with fiber reinforcement materials and surface adhesive monomers. After the puncture-resistant edge-sealing membrane material is wrapped around the edge of the foamed nickel positive electrode sheet, it effectively isolates the metal filament protrusions, preventing them from puncturing the separator and thus eliminating the safety hazard of internal short circuits caused by burrs. The acrylate components in the surface adhesive monomers provide initial adhesion properties, and after UV curing, they form strong chemical bonds or strong physical adsorption with the surface-activated microporous polyolefin membrane substrate. Under the action of cross-linking agents and photoinitiators, the monomers undergo cross-linking... The grafted polymer, formed by the polymerization and cross-linking reaction, has a three-dimensional network structure, which improves the peel strength of the puncture-resistant coating and its stability in the electrolyte. Monomers containing carboxyl groups or anhydride groups increase the adsorption capacity of the puncture-resistant coating for the electrolyte, enabling the three-dimensional cross-linked polymer network to fully absorb and bind electrolyte molecules, thereby forming a stable polymer electrolyte gel layer. The gel layer has good ionic conductivity and provides ion transport channels for the active material in the edge region of the foam positive electrode, allowing the coated part to participate in the electrochemical reaction, thereby reducing the loss of battery capacity and improving the overall energy density of the battery.

[0049] The following are some specific examples. When %, it refers to a percentage by weight. It should be noted that the following examples do not exhaustively list all possible scenarios, and unless otherwise specified, the materials used in the following examples are commercially available. Example 1

[0050] A commercially available polyethylene microporous membrane with a thickness of 25 μm, a porosity of 55%, and an average pore size of 0.2 μm was prepared as the substrate. 3 g of ethyl acrylate, 15 g of acrylic acid, 12 g of maleic anhydride, 0.5 g of crosslinking agent polydipentaerythritol pentaacrylate, 0.3 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone as a photoinitiator, and 300 g of ethanol solvent were added, along with 60 g of polyimide fiber, and mixed thoroughly.

[0051] A 25 μm thick polyethylene substrate film was activated by argon plasma treatment at a power of 100 W for 30 s. A coating solution was then uniformly applied to the surface of the activated polyethylene substrate film using a coating machine, resulting in a wet film thickness of 80 μm. The film was then immediately placed in a UV curing chamber under nitrogen protection using a 365 nm UV light source at a concentration of 50 mW / cm². 2 Irradiation at an intensity of 20 s allows the monomers to complete graft copolymerization and cross-linking reactions, and together with polyimide fibers, form a puncture-resistant coating to obtain a puncture-resistant edge-sealing membrane material.

[0052] Using high-precision automated bonding equipment, the puncture-resistant edge-sealing film is precisely bonded to the long edges of both sides of the electrode sheet. The inner edge of the puncture-resistant edge-sealing film is set 3mm away from the boundary of the active material coating area, resulting in partial overlap. Immediately after bonding, it is laminated by pressure rollers at a pressure of 0.5 MPa and a linear speed equal to the roller speed of the two preceding roller presses. It is then cut to the specified size, yielding a positive electrode sheet with an integrated puncture-resistant edge structure. Example 2

[0053] A commercially available polyethylene microporous membrane with a thickness of 25 μm, a porosity of 55%, and an average pore size of 0.2 μm was prepared as the substrate. 3 g of ethyl acrylate, 15 g of acrylic acid, 12 g of maleic anhydride, 0.5 g of crosslinking agent polydipentaerythritol pentaacrylate, 0.3 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone as a photoinitiator, and 300 g of ethanol solvent were added, along with 50 g of polyimide fiber, and mixed thoroughly.

[0054] A 25 μm thick polyethylene substrate film was activated by argon plasma treatment at a power of 100 W for 30 s. A coating solution was then uniformly applied to the surface of the activated polyethylene substrate film using a coating machine, resulting in a wet film thickness of 80 μm. The film was then immediately placed in a UV curing chamber under nitrogen protection using a 365 nm UV light source at a concentration of 50 mW / cm². 2 Irradiation at an intensity of 20 s allows the monomers to complete graft copolymerization and cross-linking reactions, and together with polyimide fibers, form a puncture-resistant coating to obtain a puncture-resistant edge-sealing membrane material.

[0055] Using high-precision automated bonding equipment, the puncture-resistant edge-sealing film is precisely bonded to the long edges of both sides of the electrode sheet. The inner edge of the edge-sealing layer is set 3mm away from the boundary of the active material coating area, forming a partial overlap. Immediately after bonding, it is laminated by pressure rollers at a pressure of 0.5MPa and a linear speed equal to the rolling speed of the two roller presses in front. It is then cut to the specified size to obtain a positive electrode sheet with an integrated puncture-resistant edge structure. Example 3

[0056] A commercially available polyethylene microporous membrane with a thickness of 25 μm, a porosity of 55%, and an average pore size of 0.2 μm was prepared as the substrate. 3 g of ethyl acrylate, 15 g of acrylic acid, 12 g of maleic anhydride, 0.5 g of crosslinking agent polydipentaerythritol pentaacrylate, 0.3 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone as a photoinitiator, and 300 g of ethanol solvent were added, along with 70 g of polyimide fiber, and mixed thoroughly.

[0057] A 25 μm thick polyethylene substrate film was activated by argon plasma treatment at a power of 100 W for 30 s. A coating solution was then uniformly applied to the surface of the activated polyethylene substrate film using a coating machine, resulting in a wet film thickness of 80 μm. The film was then immediately placed in a UV curing chamber under nitrogen protection using a 365 nm UV light source at a concentration of 50 mW / cm². 2 Irradiation at an intensity of 20 s allows the monomers to complete graft copolymerization and cross-linking reactions, and together with polyimide fibers, form a puncture-resistant coating to obtain a puncture-resistant edge-sealing membrane material.

[0058] Using high-precision automated bonding equipment, the puncture-resistant edge-sealing film is precisely bonded to the long edges of both sides of the electrode sheet. The inner edge of the edge-sealing layer is set 3mm away from the boundary of the active material coating area, forming a partial overlap. Immediately after bonding, it is laminated by pressure rollers at a pressure of 0.5MPa and a linear speed equal to the rolling speed of the two roller presses in front. It is then cut to the specified size to obtain a positive electrode sheet with an integrated puncture-resistant edge structure. Example 4

[0059] A commercially available polyethylene microporous membrane with a thickness of 25 μm, a porosity of 55%, and an average pore size of 0.2 μm was prepared as the substrate. 3 g of butyl acrylate, 27 g of itaconic acid, 0.8 g of crosslinking agent polydipentaerythritol pentaacrylate, 0.3 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone as a photoinitiator, and 300 g of ethanol solvent were added, along with 60 g of polyimide fiber, and mixed thoroughly.

[0060] A 25 μm thick polyethylene substrate film was activated by argon plasma treatment at a power of 100 W for 30 s. A coating solution was then uniformly applied to the surface of the activated polyethylene substrate film using a coating machine, resulting in a wet film thickness of 80 μm. The film was then immediately placed in a UV curing chamber under nitrogen protection using a 365 nm UV light source at a concentration of 50 mW / cm². 2 Irradiation at an intensity of 20 s allows the monomers to complete graft copolymerization and cross-linking reactions, and together with polyimide fibers, form a puncture-resistant coating to obtain a puncture-resistant edge-sealing membrane material.

[0061] Using high-precision automated bonding equipment, the puncture-resistant edge-sealing film is precisely bonded to the long edges of both sides of the electrode sheet. The inner edge of the puncture-resistant edge-sealing film is set 3mm away from the boundary of the active material coating area, resulting in partial overlap. Immediately after bonding, it is laminated by pressure rollers at a pressure of 0.5 MPa and a linear speed equal to the roller speed of the two preceding roller presses. It is then cut to the specified size, yielding a positive electrode sheet with an integrated puncture-resistant edge structure. Example 5

[0062] A commercially available polyethylene microporous membrane with a thickness of 25 μm, a porosity of 55%, and an average pore size of 0.2 μm was prepared as the substrate. 2.5 g of butyl acrylate, 22.5 g of itaconic acid, 0.67 g of crosslinking agent polydipentaerythritol pentaacrylate, 0.25 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone as a photoinitiator, and 300 g of ethanol solvent were added, along with 60 g of polyimide fiber, and mixed thoroughly.

[0063] A 25 μm thick polyethylene substrate film was activated by argon plasma treatment at a power of 100 W for 30 s. A coating solution was then uniformly applied to the surface of the activated polyethylene substrate film using a coating machine, resulting in a wet film thickness of 80 μm. The film was then immediately placed in a UV curing chamber under nitrogen protection using a 365 nm UV light source at a concentration of 50 mW / cm². 2 Irradiation at an intensity of 20 s allows the monomers to complete graft copolymerization and cross-linking reactions, and together with polyimide fibers, form a puncture-resistant coating to obtain a puncture-resistant edge-sealing membrane material.

[0064] Using high-precision automated bonding equipment, the puncture-resistant edge-sealing film is precisely bonded to the long edges of both sides of the electrode sheet. The inner edge of the edge-sealing layer is set 3mm away from the boundary of the active material coating area, forming a partial overlap. Immediately after bonding, it is laminated by pressure rollers at a pressure of 0.5MPa and a linear speed equal to the rolling speed of the two roller presses in front. It is then cut to the specified size to obtain a positive electrode sheet with an integrated puncture-resistant edge structure. Example 6

[0065] A commercially available polyethylene microporous membrane with a thickness of 25 μm, a porosity of 55%, and an average pore size of 0.2 μm was prepared as the substrate. 3.5 g of butyl acrylate, 31.5 g of itaconic acid, 0.93 g of crosslinking agent polydipentaerythritol pentaacrylate, 0.35 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone as a photoinitiator, and 300 g of ethanol solvent were added, along with 60 g of polyimide fiber, and mixed thoroughly.

[0066] A commercially available polyethylene microporous membrane with a thickness of 25 μm, a porosity of 55%, and an average pore size of 0.2 μm was prepared as the substrate. 2.5 g of butyl acrylate, 22.5 g of itaconic acid, 0.67 g of crosslinking agent polydipentaerythritol pentaacrylate, 0.25 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone as a photoinitiator, and 300 g of ethanol solvent were added, along with 60 g of polyimide fiber, and mixed thoroughly.

[0067] A 25 μm thick polyethylene substrate film was activated by argon plasma treatment at a power of 100 W for 30 s. A coating solution was then uniformly applied to the surface of the activated polyethylene substrate film using a coating machine, resulting in a wet film thickness of 80 μm. The film was then immediately placed in a UV curing chamber under nitrogen protection using a 365 nm UV light source at a concentration of 50 mW / cm². 2 Irradiation at an intensity of 20 s allows the monomers to complete graft copolymerization and cross-linking reactions, and together with polyimide fibers, form a puncture-resistant coating to obtain a puncture-resistant edge-sealing membrane material.

[0068] Using high-precision automated bonding equipment, the puncture-resistant edge-sealing film is precisely bonded to the long edges of both sides of the electrode sheet. The inner edge of the edge-sealing layer is set 3mm away from the boundary of the active material coating area, forming a partial overlap. Immediately after bonding, it is laminated by pressure rollers at a pressure of 0.5MPa and a linear speed equal to the rolling speed of the two roller presses in front. It is then cut to the specified size to obtain a positive electrode sheet with an integrated puncture-resistant edge structure. Example 7

[0069] A commercially available polyethylene microporous membrane with a thickness of 25 μm, a porosity of 55%, and an average pore size of 0.2 μm was prepared as the substrate. 3 g of ethyl acrylate, 15 g of acrylic acid, 12 g of maleic anhydride, 2 g of crosslinking agent polydipentaerythritol pentaacrylate, 0.5 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone as a photoinitiator, 1.5 g of polyN-vinylpyrrolidone as a linear polymer additive, and 300 g of ethanol solvent were added simultaneously, along with 60 g of polyimide fiber, and mixed thoroughly.

[0070] A 25 μm thick polyethylene substrate film was activated by argon plasma treatment at a power of 100 W for 30 s. A coating solution was then uniformly applied to the surface of the activated polyethylene substrate film using a coating machine, resulting in a wet film thickness of 80 μm. The film was then immediately placed in a UV curing chamber under nitrogen protection using a 365 nm UV light source at a concentration of 50 mW / cm². 2 Irradiation at an intensity of 20 s allows the monomers to complete graft copolymerization and cross-linking reactions, and together with polyimide fibers, form a puncture-resistant coating to obtain a puncture-resistant edge-sealing membrane material.

[0071] Using high-precision automated bonding equipment, the puncture-resistant edge-sealing film is precisely bonded to the long edges of both sides of the electrode sheet. The inner edge of the puncture-resistant edge-sealing film is set 3mm away from the boundary of the active material coating area, resulting in partial overlap. Immediately after bonding, it is laminated by pressure rollers at a pressure of 0.5 MPa and a linear speed equal to the roller speed of the two preceding roller presses. It is then cut to the specified size, yielding a positive electrode sheet with an integrated puncture-resistant edge structure. Example 8

[0072] A commercially available polyethylene microporous membrane with a thickness of 25 μm, a porosity of 55%, and an average pore size of 0.2 μm was prepared as the substrate. 3 g of butyl acrylate, 27 g of itaconic acid, 2 g of crosslinking agent polydipentaerythritol pentaacrylate, 0.5 g of 2-hydroxy-2-methyl-1-phenyl-1-propanone as a photoinitiator, 3.75 g of polyacrylamide as a linear polymer additive, and 300 g of ethanol solvent were added, along with 60 g of polyimide fiber, and mixed thoroughly.

[0073] A 25 μm thick polyethylene substrate film was activated by argon plasma treatment at a power of 100 W for 30 s. A coating solution was then uniformly applied to the surface of the activated polyethylene substrate film using a coating machine, resulting in a wet film thickness of 80 μm. The film was then immediately placed in a UV curing chamber under nitrogen protection using a 365 nm UV light source at a concentration of 50 mW / cm². 2 Irradiation at an intensity of 20 s allows the monomers to complete graft copolymerization and cross-linking reactions, and together with polyimide fibers, form a puncture-resistant coating to obtain a puncture-resistant edge-sealing membrane material.

[0074] Using high-precision automated bonding equipment, the puncture-resistant edge-sealing film is precisely bonded to the long edges of both sides of the electrode sheet. The inner edge of the puncture-resistant edge-sealing film is set 3mm away from the boundary of the active material coating area, resulting in partial overlap. Immediately after bonding, it is laminated by pressure rollers at a pressure of 0.5 MPa and a linear speed equal to the roller speed of the two preceding roller presses. It is then cut to the specified size, yielding a positive electrode sheet with an integrated puncture-resistant edge structure.

[0075] Comparative Example 1 Prepare the same foamed nickel positive electrode sheet as in Example 1. Use industry-standard 80μm thick masking tape with a wrapping width of 3mm. Directly attach the masking tape to the edge of the foamed nickel current collector, ensuring it completely covers the edge area of ​​the electrode sheet. Overlap the tape by 1mm at the joints to ensure no exposed areas and cover all possible burrs, thus obtaining the edge-wrapped electrode sheet of Comparative Example 1.

[0076] Comparative Example 2 Without any edge protection treatment, a positive electrode sheet with the same materials and processes as in Example 1 is obtained.

[0077] Battery assembly: Using spherical nickel hydroxide as the main active material, cobalt oxide and yttrium oxide are added as additives and mixed evenly to prepare positive electrode powder; the 1.5mm thick nickel foam is pre-pressed to 1.2mm using a roller mill at a linear speed of 5m / min, and the sheet is pulled using a brush box to control the powder amount and surface density to 185mg / cm2, and then rolled to 0.63mm using a roller mill to prepare nickel foam current collector.

[0078] The positive electrode sheets of Examples 1-8, Comparative Examples 1 and 2 were assembled together with a commercial hydrogen storage alloy negative electrode, a polyethylene separator of the same material, and a 30% potassium hydroxide aqueous solution to form an AA1600mAh nickel-metal hydride battery.

[0079] Table 1 Formulation Table of Examples Table 2 Performance Tests of Examples and Comparative Examples Table 3 shows the performance retention rate of the examples and comparative examples after immersion in alkaline electrolyte for 72 hours. Test method: For material peel strength testing, a smooth and clean stainless steel plate was used as the test board. The film material was adhered to the test board smoothly and without air bubbles. A standard pressure roller was used to roll the fiber adhesive paper multiple times to ensure tight adhesion. The standard width of the fiber paper was 25 mm. The peeling direction was 180° to the adhesion direction. The peeling speed was 300 mm / min. The peeling length was 25 mm. The test was conducted using a 180° peel strength tester. The peel force was obtained by dividing the width. The ionic conductivity of the material was obtained by electrochemical impedance spectroscopy. The sample immersed in 30% potassium hydroxide electrolyte was clamped between stainless steel blocking electrodes. The resistance in the high-frequency region was tested and the contact resistance was subtracted before being calculated based on the thickness and area. Initial discharge capacity and capacity improvement rate: The assembled AA type battery was charged at 0.1C rate for 16 hours and discharged at 0.2C rate to 1.0V at 25 degrees Celsius to measure the capacity. The percentage improvement was calculated based on the traditional polyimide tape-wrapped battery. The capacity retention rate after 300 cycles is obtained by dividing the capacity after the 300th discharge cycle by the initial capacity after 300 charge-discharge cycles at 25°C and a 1C rate. Puncture resistance was determined by puncturing the specimen with a 1mm diameter flat-head needle using a micro-force testing machine at a speed of 100mm / min, recording the maximum puncture force, and dividing the result by the specimen thickness.

[0080] The performance retention rate after immersion in alkaline electrolyte was determined by immersing the cured coating or edge-sealing membrane in a 60℃, 30% KOH aqueous solution for 72 hours. After removal and drying, the swelling rate (mass change), mass retention rate (coating dissolution loss), peel strength retention rate (peel strength after immersion / initial peel strength × 100%), and puncture resistance retention rate (puncture resistance after immersion / initial puncture resistance) were tested respectively.

[0081] As can be seen from Tables 2 and 3 above, compared with Examples 1-8, Comparative Example 1 uses 1.0 × 10... -7S / cm, through which almost an insulator, ions cannot pass through the masking tape. The puncture-resistant edge-sealing film of Examples 1-8 has a high ionic conductivity, indicating that the edge-sealing film of the invention can block metal burrs while allowing ions in the electrolyte to pass through smoothly, so that the active material in the edge-sealing area can obtain ion transport channels and partially participate in electrochemical reactions, thereby avoiding capacity loss caused by physical blocking and improving the overall energy density and cycle stability of the battery. Comparative Example 2 has a high short-circuit rate without edge sealing. Compared with Comparative Example 1, Comparative Example 2 has a higher capacity than Comparative Example 1 because the masking tape of Comparative Example 1 blocks the surface active material of the positive electrode.

[0082] The initial peel strength of Comparative Example 1 was greater than that of Examples 1-8, but after immersion in alkaline electrolyte, the peel strength of Comparative Example 1 decreased to 18%, while the peel strength retention rate of Examples 1-8 was 82%-92%, indicating that the puncture-resistant coating bonded more stably and firmly to the substrate in alkaline electrolyte. The puncture resistance retention rate of Comparative Example 1 was 12%, and the puncture resistance retention rate of Examples 1-8 was 74%-92%, indicating that the masking tape is prone to swelling and falling off in the electrolyte, and the grafted polymer that forms a three-dimensional network under UV curing remains stable in an alkaline environment. The mass retention rate and peel strength retention rate of Examples 7 and 8 are greater than those of Examples 1-6. This indicates that Examples 7 and 8, due to the introduction of linear polymers to form a semi-interpenetrating polymer network, suppress excessive swelling, and thus their stability in alkaline electrolytes is superior to that of Examples 1-6 without the addition of linear polymers.

[0083] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A method for preparing a puncture-resistant edge-sealing membrane material, characterized in that, Includes the following steps: A surface activation treatment is performed on a polyolefin membrane substrate to obtain an activated substrate; wherein the polyolefin membrane substrate is a microporous polyolefin membrane. A coating solution is obtained by mixing fiber-reinforcing material, a mixture of surface adhesive monomers, a crosslinking agent, and a photoinitiator in an ethanol solvent; wherein the surface adhesive monomer mixture includes acrylate monomers and at least one monomer selected from those containing carboxyl groups and those containing anhydride groups. The coating liquid is applied to the surface of the activated substrate to form a coating layer, thereby obtaining a coating intermediate. The coating intermediate is subjected to ultraviolet curing to induce polymerization and cross-linking reactions in the surface adhesive monomers in the coating layer, and to form a puncture-resistant coating together with the fiber reinforcement material to obtain a puncture-resistant edge-sealing membrane material.

2. The method for preparing the puncture-resistant edge-sealing membrane material according to claim 1, characterized in that, The coating liquid comprises the following components by weight: 50-70 parts fiber-reinforced material; 25-35 parts of surface-adhesive monomer; Crosslinking agent 2-6 parts; Photoinitiator 0.5-2 parts; 200-300 parts of ethanol solvent.

3. The method for preparing the puncture-resistant edge-sealing membrane material according to claim 1, characterized in that, The acrylate monomers include at least one of ethyl acrylate, butyl acrylate, and isooctyl acrylate; and / or, The carboxyl-containing monomer includes at least one selected from acrylic acid, itaconic acid, and methacrylic acid; and / or, The monomer containing anhydride groups includes at least one of maleic anhydride, itaconic anhydride, and acrylic anhydride; and / or, The crosslinking agent includes at least one of polydipentaerythritol pentaacrylate and ethoxylated trimethylolpropane triacrylate.

4. The method for preparing the puncture-resistant edge-sealing membrane material according to claim 1, characterized in that, The microporous polyolefin membrane is at least one of a microporous polyethylene membrane or a microporous polypropylene membrane.

5. The method for preparing the puncture-resistant edge-sealing membrane material according to claim 1, characterized in that, The elongation of the microporous polyolefin membrane is 15%-20%, and the tensile strength of the microporous polyolefin membrane is 2000N / m-2500N / m.

6. The method for preparing the puncture-resistant edge-sealing membrane material according to claim 1, characterized in that, The fiber reinforcement material is at least one of polyimide fiber, para-aramid fiber, meta-aramid fiber, and polyacrylonitrile fiber.

7. The method for preparing the puncture-resistant edge-sealing membrane material according to claim 1, characterized in that, When the coating intermediate is subjected to UV curing, the UV wavelength for photocuring is 350nm-400nm, and the UV light intensity is 10mW / cm². 2 -50mW / cm 2 The exposure time for ultraviolet rays is 10s-60s.

8. A method for preparing a nickel electrode, characterized in that, Includes the following steps: The puncture-resistant edge-sealing membrane material is prepared by the preparation method of the puncture-resistant edge-sealing membrane material according to claims 1-7. A positive electrode current collector is obtained by coating the positive electrode material onto the current collector and drying it. The positive electrode current collector is rolled by a rolling equipment and the floating powder on the surface of the positive electrode current collector is blown away to obtain a positive electrode intermediate. The puncture-resistant edge-sealing film is attached to the edges of both sides of the positive electrode intermediate to obtain a nickel positive electrode.

9. The edge-wrapped nickel electrode according to claim 8, characterized in that, The thickness of the puncture-resistant edge-sealing membrane is 60 μm to 120 μm.

10. A nickel-based battery, characterized in that, It includes the nickel electrode, the separator, and the negative electrode as described in any one of claims 8-9, wherein the nickel electrode, the separator, and the negative electrode are stacked sequentially.

Images