Insulating paint and preparation method thereof, insulating coating, electrode plate and battery

Abstract

The invention relates to the technical field of lithium batteries, in particular to an insulating paint and a preparation method thereof, an insulating coating, an electrode plate and a battery. The insulating coating comprises a non-aqueous solvent, a resin type compound and a fiber type compound, the resin type compound comprises insulating resin and new phenolic resin; the fiber type compound comprises modacrylic fiber, polyacrylonitrile fiber and polyurethane fiber. According to the present invention, under the condition of using the non-aqueous solvent, the resin type compound and the fiber type compound are cooperatively used, such that the insulation effect and the bonding effect are achieved, and the shrinkage during the curing of the insulation coating and the damage resistance after the curing are adjusted so as to achieve the effect of preventing the positive electrode lug or / and the negative electrode lug from being inversely inserted.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and in particular to an insulating coating and a preparation method thereof, an insulating coating, an electrode plate and a battery. Background Art

[0002] In the production process of battery cells, in order to avoid short circuits between the positive and negative electrodes, an insulating layer is generally applied to the edge of the positive electrode. The main components of the insulating layer are the binder PVDF (polyvinylidene fluoride), the solvent NMP (nitromethylpyrrolidone), and the solute ceramic powder (boehmite). The overall width is about 4mm~6mm and the thickness is about 40μm~60μm. However, due to the overall thickness of the ceramic area, it is difficult to insert the tab correctly according to the predetermined position and direction. Therefore, the tab is prone to reverse insertion during the assembly of the battery cell, and during welding, due to the low overall bonding force of the ceramic area, it is easy to fall off, resulting in the failure of the insulation effect.

[0003] Most of the existing technologies solve the problem of inverted tab insertion by adjusting the battery structure and adjusting the battery assembly process, but do not fundamentally solve the problem of inverted tab insertion caused by the material and thickness of the insulating layer.

[0004] There is also a patent document with publication number CN110911637A that discloses such a negative electrode sheet, its preparation method and lithium-ion battery, wherein the insulating paste includes a first binder, an inorganic filler and water, wherein the first binder is a thermosetting binder or a UV curing binder, and the thermosetting resin is at least one of phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, epoxy resin, silicone resin, polyurethane and polyimide. The UV curing resin is at least one of epoxy acrylate, polyurethane acrylate, polyester acrylate, acrylate containing olefin functional group and silicone / fluorine light curing resin. The inorganic inert filler is at least one of aluminum oxide, magnesium oxide, calcium oxide and titanium oxide.

[0005] This prior art uses an insulating coating layer at the root of the negative electrode tab to enhance the rigidity of the root of the negative electrode tab, prevent the negative electrode tab from wrinkling and sagging, and avoid the negative electrode tab from folding and being inserted upside down into the battery cell. However, the insulating slurry uses water as a solvent, and the water easily reacts with the positive electrode material, resulting in performance inactivation, making it unusable in the positive electrode sheet and solving the problem of the tab being inserted upside down in the positive electrode sheet. Summary of the invention

[0006] The present invention aims to solve the above-mentioned problem and provides an insulating coating and its preparation method, insulating coating, electrode plate and battery which can solve the problem of inverted insertion of positive and negative electrode tabs, especially the problem of inverted insertion of positive electrode tabs.

[0007] The technical solution of the present invention to solve the problem is: first, providing an insulating coating, including a non-aqueous solvent, a resin-type compound, and a fiber-type compound; the resin-type compound includes an insulating resin and a new phenolic resin; the fiber-type compound includes nitrile fiber, polyacrylonitrile fiber, and polyurethane fiber.

[0008] In the present application, under the condition of using a non-aqueous solvent, a resin-type compound and a fiber-type compound are used in combination to achieve the insulation effect and the bonding effect, and at the same time, the shrinkage of the insulating coating during curing and the anti-destruction property after curing are adjusted, thereby preventing the positive and / or negative electrode tabs from being inverted.

[0009] Specifically speaking, the resin compound is the basis of the coating, and the insulating resin provides the insulating effect. The new phenolic resin (Xylok) is mainly made of phenol and aryl alkyl ether through condensation reaction. It has the characteristics of strong adhesion, good chemical stability, high heat resistance, moisture resistance and alkali resistance, providing adhesion, high temperature stability and chemical stability for the insulating coating; at the same time, the new phenolic resin also has the characteristic of small shrinkage during curing, which makes the insulating coating have small size changes after curing, and can maintain a close fit with the pole piece, so that the fit between the cured insulating coating and the pole ear is more precise, and the insulating coating effectively limits the movement and inversion of the pole ear.

[0010] The fiber-type compound is a modified coating. The fiber material can form a mesh structure in the resin to play a certain connecting role, so that the various parts of the resin are interconnected, the integrity of the insulating coating is enhanced, the force it is subjected to is effectively dispersed, and the anti-destructive property of the cured insulating coating is increased to resist the inverted insertion of the pole lug. At the same time, the polyacrylonitrile fiber is acid-resistant and oxidative-resistant, and has good elasticity and high tensile strength. It can quickly return to its original shape after being stretched by external force, and can withstand large loads without breaking easily; the polyurethane fiber has the characteristics of high density, high strength, high toughness, and high wear resistance, and can effectively absorb impact energy; these two further improve the elasticity, tensile resistance, and toughness of the insulating coating after curing, so that the insulating coating is not easily damaged during or after the insertion of the pole lug, resulting in the inverted insertion of the pole lug. The nitrile chlorinated fiber is acid-resistant and chemical-resistant, and there is no shrinkage or melting phenomenon during combustion. It can solve the curing shrinkage problem of polyacrylonitrile fiber and polyurethane fiber, and maintain a small shrinkage during the curing of the insulating coating to maintain the anti-inverted insertion effect brought by the above-mentioned close fit.

[0011] In addition, the addition of various fibers also enhances the safety of the insulating coating at high temperatures, achieves a certain flame retardant effect, and improves the high temperature stability of the insulating coating.

[0012] Based on this, the technical solution of this application is completed.

[0013] In some embodiments, other commonly used additives such as binders, inorganic inert materials, etc. may be added to the insulating coating; in other embodiments, no additives may be added. As a preferred embodiment of the present invention, the insulating coating is composed of the non-aqueous solvent, insulating resin, new phenolic resin, chloronitrile fiber, polyacrylonitrile fiber, and polyurethane fiber.

[0014] In the insulating coating, the dosage ratio of each component is not limited, but the appropriate dosage ratio can maintain the insulation, adhesion, high temperature stability and anti-ear inversion of the insulating coating. As a preferred embodiment of the present invention, according to mass parts, it includes 4 to 7 parts of new phenolic resin, 2 to 5 parts of nitrile chlorinated fiber, 2 to 5 parts of polyacrylonitrile fiber, 3 to 5 parts of polyurethane fiber, 73 to 78 parts of insulating resin, and 28 to 33 parts of solvent. Further preferably, according to mass parts, it includes 5 to 6 parts of new phenolic resin, 3 to 4 parts of nitrile chlorinated fiber, 3 to 4 parts of polyacrylonitrile fiber, 3 to 4 parts of polyurethane fiber, 75 to 77 parts of insulating resin, and 30 to 32 parts of solvent.

[0015] The selection of non-aqueous solvent is not limited, and one or more solvents that are compatible with the resin-type compound and the fiber-type compound can be selected. As a preferred embodiment of the present invention, the non-aqueous solvent includes xylene and N-methylpyrrolidone (NMP). Xylene is compatible with various fibers, and NMP is compatible with various resins.

[0016] The usage ratio of xylene and N-methylpyrrolidone is not limited, as long as the dissolution of the resin-type compound and the fiber-type compound is ensured. As a preferred embodiment of the present invention, the ratio includes 11 to 13 parts of xylene and 17 to 20 parts of N-methylpyrrolidone by weight. For example, xylene can be 11 parts, 12 parts, and 13 parts; N-methylpyrrolidone can be 17 parts, 18 parts, 19 parts, and 20 parts.

[0017] The choice of insulating resin is not limited, and a material having good insulation and good adhesion to the electrode sheet can be selected. For example, phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, epoxy resin, silicone resin, polyurethane resin, polyimide resin, etc. can be selected.

[0018] In some embodiments, the specific selection of the insulating resin can further improve the adhesion, high temperature stability and damage resistance of the insulating coating. As a preferred embodiment of the present invention, the insulating resin includes an amino resin and a cross-linking resin that can be cross-linked with the amino resin, so that a three-dimensional network structure with strong toughness of the insulating base layer can be obtained.

[0019] The amino resin is used as a crosslinking agent, and its mass ratio with the crosslinking resin affects the degree of crosslinking. As a preferred embodiment of the present invention, the mass ratio of the amino resin to the crosslinking resin is 1:(8-12). For example, the mass ratio can be 1:8, 1:9, 1:10, 1:11, 1:12.

[0020] The selection of the amino resin is not limited. As preferred in the present invention, the amino resin is selected from at least one of urea-formaldehyde resin, melamine-formaldehyde resin, and polyamide-polyamine epichlorohydrin.

[0021] The selection of the cross-linking resin is not limited. As a preferred embodiment of the present invention, the cross-linking resin is selected from at least one of a polyester resin, a thermoplastic acrylic resin, and an epoxy resin.

[0022] In some embodiments, the specific selection of the cross-linked resin can further improve the insulation, adhesion and high temperature stability of the insulating coating. As a preferred embodiment of the present invention, the cross-linked resin includes polyester resin and epoxy resin. Polyester resin adhesive has low viscosity, easy wetting, high hardness of the adhesive layer after curing, good transparency, can be quickly cured under pressure at room temperature, and has good heat resistance. Epoxy resin has excellent chemical resistance, especially alkali resistance; strong adhesion to metal; good heat resistance and electrical insulation. Polyester resin and epoxy resin can complement each other, so that the insulating coating has improved adhesion, curing speed and high temperature stability.

[0023] As a preferred embodiment of the present invention, the mass ratio of the polyester resin to the epoxy resin is (6-10): 1. For example, the mass ratio may be 6:1, 7:1, 8:1, 9:1, or 10:1.

[0024] Secondly The present application also provides a method for preparing the above insulating coating, comprising the following steps: S1. The resin-type compound and part of the non-aqueous solvent are mixed uniformly to obtain a mixture a; the fiber-type compound is mixed uniformly to obtain a mixture b; S2. The mixture a and the mixture b are mixed uniformly to obtain a mixed system; S3. Evenly mix the mixed system and the remaining non-aqueous solvent to obtain an insulating coating.

[0025] The fiber-type compounds are mixed separately so that the nitrile fiber, the polyacrylonitrile fiber and the polyurethane fiber are mixed evenly to adjust the curing shrinkage of the polyacrylonitrile fiber and the polyurethane fiber.

[0026] As a preferred embodiment of the present invention, in step S1, the resin-type compound and part of the non-aqueous solvent are uniformly mixed for 110 to 130 min at a speed of 10 to 15 m / s to obtain a mixture a; the fiber-type compound is uniformly mixed for 50 to 70 min at a speed of 10 to 15 m / s to obtain a mixture b. For example, when preparing mixture a, the mixing time can be 110 min, 115 min, 120 min, 125 min, 130 min, preferably 120 min; the speed can be 10 m / s, 11 m / s, 12 m / s, 13 m / s, 14 m / s, 15 m / s, preferably 12 m / s. When preparing mixture b, the mixing time can be 50 min, 55 min, 60 min, 65 min, 70 min, preferably 60 min; the speed can be 10 m / s, 11 m / s, 12 m / s, 13 m / s, 14 m / s, 15 m / s, preferably 12 m / s.

[0027] In step S2, the mixing speed is 3-8 m / s and the mixing time is 50-70 min. A lower mixing speed is helpful for dispersing the fiber type compound in the resin type compound and preventing the fiber type compound from breaking. For example, the mixing time can be 50 min, 55 min, 60 min, 65 min, 70 min, preferably 60 min; the speed can be 3 m / s, 4 m / s, 5 m / s, 6 m / s, 7 m / s, 8 m / s, preferably 5 m / s.

[0028] In step S3, the mixing speed is 10-12 m / s, and the mixing time is 80-100 min. For example, the mixing time can be 80 min, 85 min, 90 min, 95 min, 100 min, preferably 90 min; the speed can be 10 m / s, 11 m / s, 12 m / s, preferably 11 m / s.

[0029] Secondly Another object of the present invention is to provide an insulating coating formed by curing the above insulating coating.

[0030] This insulating coating has good insulation, adhesion, high temperature stability, and anti-destruction properties, and can prevent the tab from being inverted.

[0031] Secondly Another object of the present invention is to provide an electrode plate, including an electrode plate body, the edge of which is provided with the above-mentioned insulating coating.

[0032] The thickness of the insulating coating is not limited, but an insulating coating of appropriate thickness can improve the effect of preventing the inverted insertion of the tab and ensure adhesion. As a preferred embodiment of the present invention, the thickness of the insulating coating is 5 to 20 μm. Further preferably, the thickness of the insulating coating is 8 to 15 μm. For example, it can be 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, preferably 10 μm. When the thickness of the insulating coating is too large, it may cause the tab to be difficult to insert correctly in the predetermined position and direction, resulting in the problem of inverted insertion of the tab; when the thickness of the insulating coating is too small, it may easily fall off, resulting in failure of the insulation effect.

[0033] As a preferred embodiment of the present invention, the electrode plate is a positive electrode plate. The positive electrode slurry is weakly alkaline as a whole, and the resins and fibers of the present application provide a binder function while also resisting the damage of the alkaline environment to the insulation layer.

[0034] at last Another object of the present invention is to provide a battery, comprising a tab and the above-mentioned electrode plate.

[0035] The battery cell of the present application is not prone to the problem of reverse insertion of the tab during assembly, and has the characteristic of high safety.

[0036] Beneficial effects of the present invention: 1. The present application provides an insulating coating and a preparation method thereof, as well as an insulating coating formed by curing the insulating coating. The insulating coating has low shrinkage during curing, and the cured insulating coating has good insulation, adhesion, high temperature stability, alkali resistance, and anti-destruction properties, thereby preventing the problem of inverted ear insertion.

[0037] 2. The present application provides an electrode plate and a battery using the above-mentioned insulating coating. The problem of inverted insertion of the electrode tab is not likely to occur during the assembly process of the battery cell, and the battery has the characteristic of high safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 is a CT image of the battery prepared in Example 1; Figure 2 This is a CT image of the battery prepared in Comparative Example 1. DETAILED DESCRIPTION

[0039] The following are specific embodiments of the present invention, and further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0040] Example 1 An insulating coating, in parts by mass, including 12 parts of xylene and 18 parts of NMP; also including 6.5 parts of urea-formaldehyde resin, 60.5 parts of polyester resin, 8 parts of epoxy resin, and 6 parts of new phenolic resin; also including 3 parts of chloronitrile fiber, 3 parts of polyacrylonitrile fiber, and 4 parts of polyurethane fiber.

[0041] This insulating coating is prepared by the following steps : S1. Mix xylene and NMP evenly to obtain a mixed non-aqueous solvent; mix urea-formaldehyde resin, polyester resin, epoxy resin and 30% mixed non-aqueous solvent for 120 min at a speed of 12 m / s to obtain a mixture a; mix nitrile fiber, polyacrylonitrile fiber and polyurethane fiber for 60 min at a speed of 12 m / s to obtain a mixture b.

[0042] S2. Mixing mixture a and mixture b for 60 min at a speed of 5 m / s to obtain a mixed system; S3. Mix the mixed system with the remaining 70% of the mixed non-aqueous solvent for 90 min at a speed of 11 m / s to obtain an insulating coating.

[0043] Insulating coating and positive electrode sheet , prepared by the following steps: The insulating slurry prepared above is transferred to the coating process, sprayed on the edge of the electrode plate body, and cured to obtain an insulating coating, the thickness of the insulating coating is 10 μm.

[0044] A battery, Prepared by the following steps: The positive electrode sheet with insulating coating on the edge prepared above is assembled into a battery together with the tab and other components required for the battery. Its CT image is as follows Figure 1 As shown, it is not easy for the tab to be inserted inverted.

[0045] Example 2 This embodiment is substantially the same as the embodiment 1, except that the amounts of the new phenolic resin and the fiber-type compound are different.

[0046] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NM; it also includes 6.5 parts of urea-formaldehyde resin, 60.5 parts of polyester resin, 8 parts of epoxy resin, and 8 parts of new phenolic resin; it also includes 1 part of chloronitrile fiber, 1 part of polyacrylonitrile fiber, and 6 parts of polyurethane fiber.

[0047] Example 3 This embodiment is substantially the same as the embodiment 1, except that the amounts of the new phenolic resin and the fiber-type compound are different.

[0048] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NMP; it also includes 6.5 parts of urea-formaldehyde resin, 60.5 parts of polyester resin, 8 parts of epoxy resin, and 2 parts of new phenolic resin; it also includes 6 parts of chloronitrile fiber, 6 parts of polyacrylonitrile fiber, and 2 parts of polyurethane fiber.

[0049] Example 4 This embodiment is substantially the same as the embodiment 1, except that it does not contain amino resin.

[0050] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NMP; it also includes 66.2 parts of polyester resin, 8.8 parts of epoxy resin, and 6 parts of new phenolic resin; it also includes 3 parts of chloronitrile fiber, 3 parts of polyacrylonitrile fiber, and 4 parts of polyurethane fiber.

[0051] Example 5 This embodiment is basically the same as Embodiment 1, and the only difference is that the mass ratio of the amino resin to the cross-linking resin is different.

[0052] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NMP; it also includes 8.3 parts of urea-formaldehyde resin, 58.9 parts of polyester resin, 7.8 parts of epoxy resin, and 6 parts of new phenolic resin; it also includes 3 parts of chloronitrile fiber, 3 parts of polyacrylonitrile fiber, and 4 parts of polyurethane fiber.

[0053] Example 6 This embodiment is basically the same as Embodiment 1, and the only difference is that the mass ratio of the amino resin to the cross-linking resin is different.

[0054] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NMP; it also includes 5.8 parts of urea-formaldehyde resin, 61.1 parts of polyester resin, 8.1 parts of epoxy resin, and 6 parts of new phenolic resin; it also includes 3 parts of chloronitrile fiber, 3 parts of polyacrylonitrile fiber, and 4 parts of polyurethane fiber.

[0055] Example 7 This embodiment is substantially the same as the embodiment 1, and the only difference is that it does not contain epoxy resin.

[0056] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NMP; it also includes 6.5 parts of urea-formaldehyde resin, 68.5 parts of polyester resin, and 6 parts of new phenolic resin; it also includes 3 parts of chloronitrile fiber, 3 parts of polyacrylonitrile fiber, and 4 parts of polyurethane fiber.

[0057] Example 8 This embodiment is basically the same as the embodiment 1, and the only difference is that it does not contain polyester resin.

[0058] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NMP; it also includes 6.5 parts of urea-formaldehyde resin, 68.5 parts of epoxy resin, and 6 parts of new phenolic resin; it also includes 3 parts of chloronitrile fiber, 3 parts of polyacrylonitrile fiber, and 4 parts of polyurethane fiber.

[0059] Example 9 This embodiment is basically the same as the embodiment 1, and the only difference is that the thickness of the insulating coating is 5 μm.

[0060] Example 10 This embodiment is basically the same as the embodiment 1, and the only difference is that the thickness of the insulating coating is 20 μm.

[0061] Embodiment 11 An insulating coating , in parts by mass, including 11 parts of xylene and 17 parts of NMP; also including 6 parts of urea-formaldehyde resin, 60 parts of polyester resin, 7 parts of epoxy resin, and 4 parts of new phenolic resin; also including 2 parts of chloronitrile fiber, 2 parts of polyacrylonitrile fiber, and 3 parts of polyurethane fiber.

[0062] This insulating coating is prepared by the following steps : S1. Mix xylene and NMP evenly to obtain a mixed non-aqueous solvent; mix urea-formaldehyde resin, polyester resin, epoxy resin and 35% mixed non-aqueous solvent for 110 min at a speed of 10 m / s to obtain a mixture a; mix nitrile fiber, polyacrylonitrile fiber and polyurethane fiber for 50 min at a speed of 10 m / s to obtain a mixture b.

[0063] S2. Mixing mixture a and mixture b for 50 min at a speed of 3 m / s to obtain a mixed system; S3. Mix the mixed system with the remaining 65% of the mixed non-aqueous solvent for 80 min at a speed of 10 m / s to obtain an insulating coating.

[0064] Insulating coating and positive electrode sheet , prepared by the following steps: The insulating coating is transferred to the coating process, and the insulating coating prepared above is sprayed on the edge of the electrode plate body and cured to obtain an insulating coating, the thickness of the insulating coating is 8 μm.

[0065] A battery, Prepared by the following steps: The positive electrode sheet with the insulating coating on the edge prepared above is assembled into a battery together with the tab and other components required for the battery.

[0066] Example 12 An insulating coating, in parts by mass, including 13 parts of xylene and 20 parts of NMP; also including 7 parts of urea-formaldehyde resin, 61 parts of polyester resin, 10 parts of epoxy resin, and 7 parts of new phenolic resin; also including 5 parts of nitrile fiber, 5 parts of polyacrylonitrile fiber, and 5 parts of polyurethane fiber.

[0067] This insulating coating is prepared by the following steps : S1. Mix xylene and NMP evenly to obtain a mixed non-aqueous solvent; mix urea-formaldehyde resin, polyester resin, epoxy resin and 40% mixed non-aqueous solvent for 130 min at a speed of 15 m / s to obtain a mixture a; mix nitrile fiber, polyacrylonitrile fiber and polyurethane fiber for 70 min at a speed of 15 m / s to obtain a mixture b.

[0068] S2. Mixing mixture a and mixture b for 70 min at a speed of 8 m / s to obtain a mixed system; S3. The mixed system was mixed with the remaining 60% of the mixed non-aqueous solvent for 100 min at a speed of 12 m / s to obtain an insulating coating.

[0069] Insulating coating and positive electrode sheet , prepared by the following steps: The insulating coating is transferred to the coating process, and the insulating coating prepared above is sprayed on the edge of the electrode plate body and cured to obtain an insulating coating, the thickness of the insulating coating is 12 μm.

[0070] A battery, Prepared by the following steps: The positive electrode sheet with the insulating coating on the edge prepared above is assembled into a battery together with the tab and other components required for the battery.

[0071] Comparative Example 1 The insulating coating is obtained by conventional PVDF ceramic slurry. This PVDF ceramic slurry includes 1 part of binder PVDF (polyvinylidene fluoride), 100 parts of solvent NMP (nitromethylpyrrolidone), and 40 parts of solute ceramic powder (boehmite) by weight. Its CT image is as follows Figure 2 As shown, the tabs are prone to being inverted.

[0072] Blank example This blank example is basically the same as Example 1, with the only difference being that it does not contain new phenolic resin and fiber-type compound, an equal mass of phenolic resin is used to replace the new phenolic resin, and an equal mass of polypropylene fiber is used to replace the fiber-type compound. The role of the phenolic resin and the polypropylene fiber is to ensure that the mass fraction of the non-aqueous solvent and the insulating resin in the insulating coating is consistent with that in Example 1.

[0073] Specifically, in parts by mass, it includes 12 parts of xylene, 18 parts of NMP; 6.5 parts of urea-formaldehyde resin, 60.5 parts of polyester resin, 8 parts of epoxy resin; 6 parts of phenolic resin; and 10 parts of polypropylene fiber.

[0074] Comparative Example 2 This comparative example is basically the same as Example 1, the only difference being that: no new phenolic resin is contained, and the new phenolic resin is replaced by an equal mass of phenolic resin, and the role of the phenolic resin is to ensure that the mass fractions of the non-aqueous solvent, insulating resin, and fiber-type compound in the insulating coating are consistent with those in Example 1.

[0075] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NMP; it also includes 6.5 parts of urea-formaldehyde resin, 60.5 parts of polyester resin, 8 parts of epoxy resin, and 6 parts of phenolic resin; it also includes 3 parts of chloronitrile fiber, 3 parts of polyacrylonitrile fiber, and 4 parts of polyurethane fiber.

[0076] Comparative Example 3 This comparative example is basically the same as Example 1, the only difference being that it does not contain a fiber-type compound, and is replaced by an equal mass of polypropylene fiber. The role of the polypropylene fiber is to ensure that the mass fractions of the non-aqueous solvent, insulating resin, and new phenolic resin in the insulating coating are consistent with those in Example 1.

[0077] Specifically: in terms of mass, it includes 12 parts of xylene, 18 parts of NMP; it also includes 6.5 parts of urea-formaldehyde resin, 60.5 parts of polyester resin, 8 parts of epoxy resin, and 6 parts of new phenolic resin; it also includes 10 parts of polypropylene fiber.

[0078] Comparative Example 4 This comparative example is basically the same as Example 1, except that the nylon fiber is not contained and the nylon fiber is replaced by polypropylene fiber of equal mass.

[0079] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NMP; it also includes 6.5 parts of urea-formaldehyde resin, 60.5 parts of polyester resin, 8 parts of epoxy resin, and 6 parts of new phenolic resin; it also includes 3 parts of polypropylene fiber, 3 parts of polyacrylonitrile fiber, and 4 parts of polyurethane fiber.

[0080] Comparative Example 5 This comparative example is basically the same as Example 1, except that the polyacrylonitrile fiber is not contained and is replaced by polypropylene fiber of equal mass.

[0081] Specifically: in terms of mass, it includes 12 parts of xylene and 18 parts of NMP; it also includes 6.5 parts of urea-formaldehyde resin, 60.5 parts of polyester resin, 8 parts of epoxy resin, and 6 parts of new phenolic resin; it also includes 3 parts of chloronitrile fiber, 3 parts of polypropylene fiber, and 4 parts of polyurethane fiber.

[0082] Performance Testing Obtain CT images of the batteries prepared in the examples and comparative examples to observe whether the tab inversion phenomenon occurs.

[0083] The tensile bonding strength of the insulating coatings obtained in the examples and comparative examples was tested, and the test results are shown in Table 1 below.

[0084] The carbonization temperatures of the insulating coatings obtained in the examples and comparative examples were tested, and the test results are shown in Table 1 below.

[0085] Table 1. As shown in Table 1, it can be seen from the comparative examples and comparative examples that the insulating coating of the present application uses a specific resin type compound and a specific fiber type compound in combination, which can effectively prevent the tab from being inverted after curing.

[0086] By comparing Example 1, the blank example, Comparative Example 2 and Comparative Example 3, it can be seen that whether the new phenolic resin or the fiber-type compound is lacking, the effect of preventing the inverted insertion of the pole ear will be affected. This may be because the new phenolic resin mainly prevents the insulating coating from shrinking too much when it is cured, and the fiber-type compound mainly adjusts the anti-destruction property of the insulating coating after it is cured. Both are indispensable: if the insulating coating shrinks too much when it is cured, it will cause a gap between the insulating coating and the pole piece, and the insulating coating will be easy to loosen. At the same time, the gap in the insulating coating for the insertion of the pole ear will not match the size of the pole ear, so that the insulating coating cannot effectively restrict the movement and inverted insertion of the pole ear; if the insulating coating has low anti-destruction property after curing, even if the insulating coating and the pole piece and the pole ear can be accurately connected, the insulating coating will be easily damaged, resulting in the inverted insertion of the pole ear.

[0087] Continuing to compare Comparative Examples 4 and 5, it can be seen that the three fibers in the fiber-type compound are also indispensable to ensure the anti-pole ear inverted insertion effect. This may be because polyacrylonitrile fiber and polyurethane fiber are mainly used to adjust the anti-destruction property of the insulating coating after curing, and nitrile-chlorofiber fiber is mainly used to adjust the curing shrinkage of polyacrylonitrile fiber and polyurethane fiber. The lack of any one of them will also affect the shrinkage of the insulating coating during curing and the anti-destruction property after curing.

[0088] In addition, it can be seen from the comparison in the embodiments that, based on the common use of new phenolic resin and nitrile fiber, phenolic resin, and polyurethane fiber, the control of the amount of each component, the selection of insulating resin, and the control of the thickness of the insulating coating can further improve the adhesion and high-temperature stability of the insulating coating, and improve the use effect of the insulating coating on the pole piece.

[0089] By comparing Example 1 with Examples 2 and 3, it can be seen that the appropriate amount of new phenolic resin and fiber-type compound can ensure that the tensile bonding strength and high-temperature stability of the insulating coating are both at a high level. This may be because too little new phenolic resin or / and too much fiber-type compound affect the uniformity of the dispersion of the fiber-type compound in the resin.

[0090] Comparing Example 1 with Example 4, it can be seen that the use of amino resin, polyester resin and epoxy resin as insulating resins can effectively improve the tensile bonding strength and high temperature stability of the insulating coating. This may be because the three can be cross-linked to obtain a three-dimensional network structure with strong and tough insulating base layer. Continuing to compare Example 1 with Examples 5 and 6, it can be seen that when cross-linking, the amount ratio of amino resin, polyester resin and epoxy resin is limited to a certain range, which can control the cross-linking density and the dispersion effect of the fiber-type compound in the insulating base layer, thereby improving the bonding force and high temperature stability of the insulating coating. Continuing to compare Example 1 with Examples 7 and 8, it can be seen that the use of polyester resin and epoxy resin at the same time can be used synergistically to improve the viscosity and curing speed.

[0091] By comparing Example 1 with Examples 9 and 10, it can be seen that an insulating coating of appropriate thickness can ensure adhesion. When the insulating coating is too thin and has low tensile bonding strength, it may easily fall off, resulting in failure of the insulation effect.

[0092] The specific embodiments described herein are merely examples of the spirit of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in similar ways, but they will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

Claims

1. An insulating coating, characterized in that: including non-aqueous solvents, resinous compounds, and fiber-type compounds; The resin type compound includes insulating resin and new phenolic resin; The fiber-type compounds include nylon fiber, polyacrylonitrile fiber, and polyurethane fiber.

2. The insulating coating according to claim 1, characterized in that: In parts by mass, it includes 4-7 parts of new phenolic resin, 2-5 parts of nitrile fiber, 2-5 parts of polyacrylonitrile fiber, 3-5 parts of polyurethane fiber, 73-78 parts of insulating resin and 28-33 parts of non-aqueous solvent.

3. An insulating coating according to claim 1 or 2, characterized in that: The insulating resin includes an amino resin and a cross-linking resin capable of cross-linking with the amino resin; The cross-linking resin is selected from at least one of polyester resin, thermoplastic acrylic resin and epoxy resin.

4. The insulating coating according to claim 3, characterized in that: The mass ratio of the amino resin to the cross-linking resin is 1:(8-12).

5. The insulating coating according to claim 3, characterized in that: The cross-linking resin includes polyester resin and epoxy resin.

6. A method for preparing the insulating coating according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. The resin-type compound and part of the non-aqueous solvent are mixed uniformly to obtain a mixture a; the fiber-type compound is mixed uniformly to obtain a mixture b; S2. The mixture a and the mixture b are mixed uniformly to obtain a mixed system; S3. Evenly mix the mixed system and the remaining non-aqueous solvent to obtain an insulating coating.

7. An insulating coating, characterized in that: The insulating coating is formed by curing the insulating coating as claimed in any one of claims 1 to 5.

8. An electrode plate, comprising an electrode plate body, characterized in that: The edge of the electrode plate body is provided with the insulating coating as claimed in claim 7.

9. The electrode plate according to claim 8, characterized in that: The thickness of the insulating coating is 5-20 μm.

10. A battery, comprising a tab, characterized in that: Also includes the electrode plate as described in claim 8.

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