Roll-pressure-resistant current collector and application thereof

Abstract

The invention provides an anti-rolling current collector and application thereof. The provided current collector comprises an anti-rolling thin film layer and a metal layer, wherein the metal layer is positioned on at least one surface of the anti-rolling thin film layer; the rolling-resistant thin film layer is formed by melting a hydrogen bond cross-linking type photoresponse polymer, a cross-linking agent and a high polymer material. The invention also provides a positive plate, a battery and an electric device.

Description

Technical Field

[0001] The invention relates to the field of batteries, and in particular to a rolling-resistant current collector and applications thereof. Background Art

[0002] The composite current collector is a battery material with a "sandwich" structure, consisting of an inner polymer layer, a middle metal conductive layer and an outer corrosion-resistant material. The inner polymer layer is the positive electrode of the battery, the metal conductive layer is the negative electrode of the battery, and the outer corrosion-resistant material provides isolation protection for the battery. The advantage of the composite current collector is that it has high energy density and good cycle life, while also providing sufficient overcharge protection, stable large current discharge capacity and excellent safety performance. It can be widely used in high-performance battery fields, such as solar cells, lithium-ion batteries, etc. Compared with traditional aluminum foil or copper foil, the composite current collector can reduce the cost of the battery, improve the energy density and safety performance of the battery, and is therefore considered to be one of the best solutions for achieving high energy density batteries.

[0003] In the production process of lithium battery cells, there is an indispensable rolling process. The existing rolling technology causes the tension and extension of the pole piece coating and the composite current collector area to be different, resulting in a large tensile stress in the composite current collector area of ​​the pole piece after rolling, which causes the edge of the composite current collector to wrinkle, and then causes the pole ear to fold and cut poorly in the subsequent production process. In order to reduce the edge wrinkling problem, most companies change the structural design of the rolling equipment, but the solution is not effective. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. The present invention provides a rolling-resistant current collector and an electrode sheet, a battery and an electrical device. The provided rolling-resistant current collector is provided with an anti-rolling film layer, in which the hydrogen-bonded cross-linked photoresponsive polymer contained can be cross-linked with a cross-linking agent to form a bonded polymer, thereby causing the shrinkage of the polymer film, thereby solving the problem of wrinkling at the edge of the electrode sheet.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] In the first aspect of the present invention, an anti-rolling current collector is provided, comprising an anti-rolling film layer and a metal layer, wherein the metal layer is located on at least one surface of the anti-rolling film layer; the anti-rolling film layer comprises a hydrogen bond cross-linked photoresponsive polymer, a cross-linking agent and a polymer material.

[0007] The anti-rolling current collector provided by the present invention is provided with an anti-rolling film layer, which contains a hydrogen-bonded cross-linked photoresponsive polymer, a cross-linking agent and a polymer material. These three materials can be used to form a shrinkable film. When heated and illuminated during rolling, the stretching of the rolled part can be reduced, thereby solving the problem of edge wrinkling. Moreover, the hydrogen-bonded cross-linked photoresponsive polymer can form a hydrogen-bonded network under ultraviolet light, and cutting the hydrogen bonds can soften and expand the polymer. After adding a heat-sensitive cross-linking agent, these cross-linking agents will undergo a cross-linking reaction when heated to form a three-dimensional spatial network, embedding the hydrogen-bonded polymer, and causing the shrinkage of the polymer film. Therefore, by controlling the conditions of ultraviolet light and heat-sensitive cross-linking reactions, precise shrinkage of the polymer film can be achieved, thereby solving the problem of edge wrinkling.

[0008] According to an embodiment of the present invention, the above-mentioned rolling-resistant current collector may further include the following technical features:

[0009] According to an embodiment of the present invention, the mass ratio of the hydrogen-bonded cross-linked photoresponsive polymer, the cross-linking agent and the polymer material is (2.5-10): (2.5-10): (80-95). According to a preferred embodiment of the present invention, the mass ratio of the hydrogen-bonded cross-linked photoresponsive polymer, the cross-linking agent and the polymer material is (2.5-6): (2.5-6): (88-95).

[0010] According to an embodiment of the present invention, the hydrogen-bond cross-linked photoresponsive polymer is a linear azobenzene polymer containing hydrogen bonds. According to an embodiment of the present invention, the hydrogen-bond cross-linked photoresponsive polymer is obtained by addition polymerization of a diol containing azobenzene groups and diisocyanate.

[0011] According to an embodiment of the present invention, the crosslinking agent is at least one of acrylic acid, bis(4-chlorophenoxy) glucose, diethylene glycol diacrylate, N,N'-methylenebisacrylamide, and dihydroxyethyl phthalate.

[0012] According to an embodiment of the present invention, the polymer material includes at least one of polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyimide, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene oxide, polystyrene and polyamide.

[0013] According to an embodiment of the present invention, the anti-rolling current collector further comprises a substrate layer, and the anti-rolling film layer is located on at least one surface of the substrate layer.

[0014] According to an embodiment of the present invention, the thickness of the anti-rolling film layer is 1 μm to 8 μm; the thickness of the metal layer is 100 nm to 1000 nm.

[0015] According to an embodiment of the present invention, the anti-rolling film layer is formed by melting a hydrogen-bond cross-linked photoresponsive polymer, a cross-linking agent and a polymer material, and the anti-rolling film layer is prepared by the following method:

[0016] The hydrogen-bond cross-linked photoresponsive polymer, the cross-linking agent and the polymer material are mixed, subjected to a first heating and melting process, and extruded to obtain a polymer slice;

[0017] The polymer slices are subjected to a crystallization treatment at a predetermined temperature and a drying treatment, the dried polymer slices are subjected to a second heating and melting treatment, extruded into a cast sheet, and cooled to form a polymer cast sheet;

[0018] The polymer casting sheet is heated to perform longitudinal stretching and transverse stretching and shaping to obtain the rolling-resistant film layer;

[0019] According to an embodiment of the present invention, the temperature of the first heating and melting is 220-260 degrees Celsius.

[0020] According to an embodiment of the present invention, the predetermined temperature is 130-180 degrees Celsius.

[0021] According to an embodiment of the present invention, the temperature of the second heating and melting is 250-300 degrees Celsius.

[0022] According to an embodiment of the present invention, the temperature of the longitudinal stretching is 100 to 130 degrees Celsius, and the stretching ratio is 2:1 to 4:1.

[0023] According to an embodiment of the present invention, the temperature of the transverse stretching is 100 to 130 degrees Celsius, and the stretching ratio is 2:1 to 4:1.

[0024] According to an embodiment of the present invention, the metal layer is prepared by the following method:

[0025] Melting and evaporating the metal, and cooling the metal so that the evaporated metal atoms are deposited on the surface of the anti-rolling film layer to obtain a metal layer, wherein the metal layer is deposited on the surface of the anti-rolling film layer;

[0026] According to an embodiment of the present invention, the temperature of the melting and evaporation is 1200-1800 degrees Celsius.

[0027] A second aspect of the present invention provides an electrode sheet, comprising the anti-rolling current collector described in the first aspect, and an active material layer attached to at least one surface of the anti-rolling current collector.

[0028] A third aspect of the present invention provides a battery, which includes the electrode sheet described in the second aspect.

[0029] A fourth aspect of the present invention provides an electrical device comprising the battery described above.

[0030] The beneficial effects achieved by the present invention are:

[0031] (1) The shrink film was manufactured by optimizing the material composition. Heating and irradiation were performed during rolling to reduce the stretching of the rolled part, thus solving the problem of edge wrinkling.

[0032] (2) Hydrogen-bonded cross-linked photoresponsive polymers can form hydrogen-bonded networks under ultraviolet light, and cutting hydrogen bonds can soften and expand the polymer. After adding heat-sensitive cross-linking agents, these cross-linking agents will undergo cross-linking reactions when heated to form a three-dimensional network, embedding hydrogen-bonded polymers and causing the polymer film to shrink. Therefore, by controlling the conditions of ultraviolet light and heat-sensitive cross-linking reactions, precise shrinkage of polymer films can be achieved, thereby solving the problem of edge wrinkling. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 1 is a schematic diagram of the structure of a rolling-resistant current collector provided according to an embodiment of the present invention, wherein reference numeral 1 is an anti-rolling film layer, and reference numeral 2 is a metal layer.

[0034] Figure 2 1 is a schematic structural diagram of a rolling-resistant current collector provided according to an embodiment of the present invention, wherein reference numeral 1 is an anti-rolling film layer, 2 is a metal layer, and 3 is a substrate layer. DETAILED DESCRIPTION

[0035] Embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0036] In a first aspect of the present invention, an anti-rolling current collector is provided, comprising an anti-rolling film layer and a metal layer, wherein the metal layer is located on at least one surface of the anti-rolling film layer; the anti-rolling film layer comprises a hydrogen bond cross-linked photoresponsive polymer, a cross-linking agent and a polymer material.

[0037] According to a specific embodiment of the present invention, Figure 1 As shown in FIG. 1 , the metal layer is located on both sides of the anti-rolling film layer (located on the outside of the anti-rolling film layer), wherein reference numeral 1 is the anti-rolling film layer, and reference numeral 2 is the metal layer. Figure 2 As shown, it further includes a substrate layer, the anti-rolling film layer is located on both sides of the substrate layer (located on the outside of the substrate layer), and the metal layer is located on both sides of the anti-rolling film layer (located on the outside of the anti-rolling film layer), wherein label 1 is the anti-rolling film layer, label 2 is the metal layer, and label 3 is the substrate layer.

[0038] The anti-rolling current collector provided by the present invention is provided with an anti-rolling film layer, which contains a hydrogen-bonded cross-linked photoresponsive polymer, a cross-linking agent and a polymer material. These three materials can be used to form a shrinkable film. When heated and illuminated during rolling, the stretching of the rolled part can be reduced, thereby solving the problem of edge wrinkling. Moreover, the hydrogen-bonded cross-linked photoresponsive polymer can form a hydrogen-bonded network under ultraviolet light, and cutting the hydrogen bonds can soften and expand the polymer. After adding a heat-sensitive cross-linking agent, these cross-linking agents will undergo a cross-linking reaction when heated to form a three-dimensional spatial network, embedding the hydrogen-bonded polymer, and causing the polymer film to shrink. Therefore, by controlling the conditions of ultraviolet light and heat-sensitive cross-linking reactions, precise shrinkage of the polymer film can be achieved, thereby solving the problem of edge wrinkling.

[0039] According to an embodiment, the mass ratio of the hydrogen-bonded cross-linked photoresponsive polymer, the cross-linking agent and the polymer material is (2.5-10): (2.5-10): (80-95). According to a preferred embodiment of the present invention, the mass ratio of the hydrogen-bonded cross-linked photoresponsive polymer, the cross-linking agent and the polymer material is (2.5-6): (2.5-6): (88-95). According to a preferred embodiment, the mass ratio of the hydrogen-bonded cross-linked photoresponsive polymer, the cross-linking agent and the polymer material is (3-5): (3-5): (90-94). For example, it is 5:5:90.

[0040] According to an embodiment, the hydrogen-bonded cross-linked photoresponsive polymer is a linear azobenzene polymer containing hydrogen bonds. These hydrogen-bonded linear azobenzene polymers are linear main-chain azobenzene liquid crystal polymers with high hydrogen-bond cross-linking density, which can be synthesized by addition polymerization of azobenzene diol and diisocyanate. It can be obtained with reference to the Chinese patent text with application number 202010686469.0 and announcement number CN111875765B. The material is simple to synthesize, and a high-density hydrogen bond is introduced on the basis of the linear structure, so that the material has good crystallinity and liquid crystal properties, ensuring good processing performance while improving the mechanical properties of the material. Under ultraviolet light, the azobenzene group inside this material will produce photoisomerization, reducing the glass transition temperature (Tg) of the material. After increasing the ultraviolet light intensity, the photothermal effect of azobenzene will increase the temperature of the material, prompting the hydrogen bonds in the material to produce dynamic exchange. By using these two changes as reversible phases and the high-temperature stable crystalline phase as the fixed phase, we can achieve precise photo-controlled editing and recovery of permanent and temporary shapes by simply adjusting the light intensity. The advantage of this method is that it uses the synergistic effect of the photothermal effect of azobenzene polymers and the photoinduced Tg reduction to separate the two overlapping reversible phase transition temperature zones, achieving multiple shape memories and recovery at lower temperatures. A lower shape recovery temperature is also beneficial to avoid the occurrence of thermal creep, and a higher shape fixation rate and recovery rate can be obtained with only a linear structure.

[0041] According to a specific embodiment, the hydrogen-bonded cross-linked photoresponsive polymer is a linear azobenzene polymer PAB1-HDI (M n-GPC ~12000), or a linear azobenzene polymer containing hydrogen bonds PAB2-IPDI (M n-GPC ~18000) These polymers and their preparation methods are all recorded in the Chinese patent text with application number 202010686469.0 and publication number CN111875765B. Those skilled in the art can cite them in the present invention as needed.

[0042] According to a specific embodiment, the crosslinking agent is at least one of acrylic acid, bis(4-chlorophenoxy) glucose, diethylene glycol diacrylate, N,N'-methylenebisacrylamide, and dihydroxyethyl phthalate, preferably acrylic acid.

[0043] According to a specific implementation, the polymer material includes at least one of polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyimide, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene oxide, polystyrene and polyamide.

[0044] According to a specific embodiment, the thickness of the anti-rolling film layer is 1 μm to 8 μm, for example, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm or 8 μm, preferably 4 to 8 μm, for example, 4 μm, 5 μm, 6 μm, 7 μm or 8 μm.

[0045] According to a specific embodiment, the thickness of the metal layer is 100nm-1000nm, for example, 100nm, 200nm, 300nm, 400nm, 500nm, 600nm, 700nm, 800nm, 900nm, 1000nm, preferably 800-1000nm, for example, 800nm, 900nm or 1000nm.

[0046] According to an embodiment of the present invention, the anti-rolling film layer is formed by melting a hydrogen-bond cross-linked photoresponsive polymer, a cross-linking agent and a polymer material, and the anti-rolling film layer is prepared by the following method:

[0047] The hydrogen-bond cross-linked photoresponsive polymer, the cross-linking agent and the polymer material are mixed, subjected to a first heating and melting process, and extruded to obtain a polymer slice;

[0048] The polymer slices are subjected to a crystallization treatment at a predetermined temperature and a drying treatment, the dried polymer slices are subjected to a second heating and melting treatment, extruded into a cast sheet, and cooled to form a polymer cast sheet;

[0049] The polymer casting sheet is heated to be stretched longitudinally and transversely, and shaped to obtain the rolling-resistant film layer;

[0050] According to a specific embodiment, the temperature of the first heating and melting is 220-260 degrees Celsius. According to a preferred embodiment, the temperature of the first heating and melting is 240-250 degrees Celsius, for example, 245 degrees Celsius.

[0051] According to a specific embodiment, the predetermined temperature is 130 to 180 degrees Celsius. According to a preferred embodiment, the predetermined temperature is 140 to 160 degrees Celsius, for example, 150 degrees Celsius. The temperature of the drying process is 150 to 170 degrees Celsius.

[0052] According to a specific embodiment, the temperature of the second heating and melting is 250 to 300 degrees Celsius. According to a preferred embodiment, the temperature of the second heating and melting is 260 to 280 degrees Celsius.

[0053] According to a specific embodiment, the temperature of the longitudinal stretching is 100 to 130 degrees Celsius (for example, 110 degrees Celsius), and the stretching ratio is 2:1 to 4:1 (for example, 3:1).

[0054] According to a specific embodiment, the temperature of the transverse stretching is 100 to 130 degrees Celsius (for example, 110 degrees Celsius), and the stretching ratio is 2:1 to 4:1 (for example, 3:1).

[0055] According to a specific embodiment, the metal layer is prepared by the following method:

[0056] Melting and evaporating the metal, and cooling the metal so that the evaporated metal atoms are deposited on the surface of the anti-rolling film layer to obtain a metal layer, wherein the metal layer is deposited on the surface of the anti-rolling film layer;

[0057] According to a specific embodiment, the temperature of the melting and evaporation is 1200-1800 degrees Celsius. According to a specific embodiment, the temperature of the melting and evaporation is 1300-1500 degrees Celsius, for example, 1400 degrees Celsius.

[0058] A second aspect of the present invention provides an electrode sheet, comprising the anti-rolling current collector described in the first aspect, and an active material layer attached to at least one surface of the anti-rolling current collector.

[0059] A third aspect of the present invention provides a battery, which includes the electrode sheet described in the second aspect.

[0060] A fourth aspect of the present invention provides an electrical device comprising the battery described above.

[0061] The technical scheme of the present invention is described below by way of examples. It should be noted that these examples are only used to facilitate the understanding of those skilled in the art and should not be regarded as limiting the scope of protection of the present invention. The reagents in the examples can be purchased commercially or prepared by methods known in the art.

[0062] Example 1

[0063] Embodiment 1 provides a method for preparing a rolling-resistant current collector, comprising the following steps:

[0064] S1. Preparation of anti-rolling film layer;

[0065] (1) According to the mass percentage, 90.0wt% PET (polyethylene terephthalate), 5.0wt% hydrogen bond cross-linked photoresponsive polymer (which is a linear azobenzene polymer containing hydrogen bonds PAB2-IPDI (M n-GPC ~18000), the polymer and its preparation method refer to CN111875765B), 5.0wt% acrylic acid, heated to 245℃ and melted, mixed, extruded, molded and sliced ​​to obtain polymer slices;

[0066] (2) placing the polymer slice in a crystallizer, heating it to 150°C, crystallizing it, keeping it warm for 40 minutes, transferring the polymer slice to a drying tower, heating it to 155°C, drying it for 140 minutes, heating the dried polymer slice to 270°C, extruding it through melt, and cooling it with a casting roller and water cooling to obtain a polymer casting sheet;

[0067] (3) heating the cast sheet to 90° C., preheating for 10 seconds, heating it to 110° C., longitudinally stretching it at a stretching ratio of 3:1, and after the longitudinal stretching is completed, heating it to 170° C., heat setting it for 10 seconds, cooling it to 40° C., cooling it to form it, and obtaining a longitudinally stretched cast sheet;

[0068] (4) heating the longitudinally stretched cast sheet to 90° C., preheating for 10 seconds, heating it to 120° C., longitudinally stretching it at a stretching ratio of 3:1, heating it to 170° C., heat setting it for 10 seconds, cooling it to 110° C., cooling it to form it, and obtaining a rolling-resistant film layer with a thickness of 6 μm;

[0069] S2. Preparing a reinforced metal layer;

[0070] The anti-rolling film layer is placed in a vacuum evaporation chamber, and the high-purity aluminum wire in the metal evaporation chamber is melted and evaporated at a high temperature of 1400°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both sides of the surface of the polymer substrate layer to form a metal layer with a thickness of 1000nm; after taking out, an anti-rolling current collector is obtained.

[0071] Example 2

[0072] Embodiment 2 provides a method for preparing a rolling-resistant current collector, comprising the following steps:

[0073] S1. Preparation of anti-rolling film layer;

[0074] (1) According to the mass percentage, 94.0wt% PET, 3.0wt% hydrogen bond cross-linked photoresponsive polymer (which is a linear azobenzene polymer containing hydrogen bonds PAB2-IPDI (M n-GPC ~18000), the polymer and its preparation method refer to CN111875765B), 3.0wt% acrylic acid, heated to 245℃ and melted, mixed, extruded, molded and sliced ​​to obtain polymer slices;

[0075] (2) placing the polymer slice in a crystallizer, heating it to 150°C, crystallizing it, keeping it warm for 40 minutes, transferring the polymer slice to a drying tower, heating it to 155°C, drying it for 140 minutes, heating the dried polymer slice to 270°C, extruding it through melt, and cooling it with a casting roller and water cooling to obtain a polymer casting sheet;

[0076] (3) heating the cast sheet to 90° C., preheating for 10 seconds, heating it to 110° C., longitudinally stretching it at a stretching ratio of 3:1, and after the longitudinal stretching is completed, heating it to 170° C., heat setting it for 10 seconds, cooling it to 40° C., cooling it to form it, and obtaining a longitudinally stretched cast sheet;

[0077] (4) heating the longitudinally stretched cast sheet to 90° C., preheating for 10 seconds, heating it to 120° C., longitudinally stretching it at a stretching ratio of 3:1, heating it to 170° C., heat setting it for 10 seconds, cooling it to 110° C., cooling it to form it, and obtaining a rolling-resistant film layer with a thickness of 6 μm;

[0078] S2. Preparing a reinforced metal layer;

[0079] The anti-rolling film layer is placed in a vacuum evaporation chamber, and the high-purity aluminum wire in the metal evaporation chamber is melted and evaporated at a high temperature of 1400°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both sides of the surface of the polymer substrate layer to form a metal layer with a thickness of 1000nm; after taking out, an anti-rolling current collector is obtained.

[0080] Example 3

[0081] Embodiment 3 provides a method for preparing a rolling-resistant current collector, comprising the following steps:

[0082] S1. Preparation of anti-rolling film layer;

[0083] (1) According to the mass percentage, 84.0wt% PET, 8.0wt% hydrogen bond cross-linked photoresponsive polymer (which is a linear azobenzene polymer containing hydrogen bonds PAB2-IPDI (M n-GPC ~18000), the polymer and its preparation method refer to CN111875765B), 8.0wt% acrylic acid, heated to 245℃ and melted, mixed, extruded, molded and sliced ​​to obtain polymer slices;

[0084] (2) placing the polymer slice in a crystallizer, heating it to 150°C, crystallizing it, keeping it warm for 40 minutes, transferring the polymer slice to a drying tower, heating it to 155°C, drying it for 140 minutes, heating the dried polymer slice to 270°C, extruding it through melt, and cooling it with a casting roller and water cooling to obtain a polymer casting sheet;

[0085] (3) heating the cast sheet to 90° C., preheating for 10 seconds, heating it to 110° C., longitudinally stretching it at a stretching ratio of 3:1, and after the longitudinal stretching is completed, heating it to 170° C., heat setting it for 10 seconds, cooling it to 40° C., cooling it to form it, and obtaining a longitudinally stretched cast sheet;

[0086] (4) heating the longitudinally stretched cast sheet to 90° C., preheating for 10 seconds, heating it to 120° C., longitudinally stretching it at a stretching ratio of 3:1, heating it to 170° C., heat setting it for 10 seconds, cooling it to 110° C., cooling it to form it, and obtaining a rolling-resistant film layer with a thickness of 6 μm;

[0087] S2. Preparing a reinforced metal layer;

[0088] The anti-rolling film layer is placed in a vacuum evaporation chamber, and the high-purity aluminum wire in the metal evaporation chamber is melted and evaporated at a high temperature of 1400°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both sides of the surface of the polymer substrate layer to form a metal layer with a thickness of 1000nm; after taking out, an anti-rolling current collector is obtained.

[0089] Comparative Example 1

[0090] Compared with the technical solution of Example 1, Comparative Example 1 does not add hydrogen bond cross-linking photoresponsive polymer and acrylic acid.

[0091] Comparative Example 2

[0092] Comparative Example 2 provides a method for preparing a rolling-resistant current collector, comprising the following steps:

[0093] S1. Preparation of anti-rolling film layer;

[0094] (1) According to the mass percentage, 98.0wt% PET, 1.0wt% hydrogen bond cross-linked photoresponsive polymer (which is a linear azobenzene polymer containing hydrogen bonds PAB2-IPDI (M n-GPC ~18000), the polymer and its preparation method refer to CN111875765B), 1.0wt% acrylic acid, heated to 245℃ and melted, mixed, extruded, molded and sliced ​​to obtain polymer slices;

[0095] (2) placing the polymer slice in a crystallizer, heating it to 150°C, crystallizing it, keeping it warm for 40 minutes, transferring the polymer slice to a drying tower, heating it to 155°C, drying it for 140 minutes, heating the dried polymer slice to 270°C, extruding it through melt, and cooling it with a casting roller and water cooling to obtain a polymer casting sheet;

[0096] (3) heating the cast sheet to 90° C., preheating for 10 seconds, heating it to 110° C., longitudinally stretching it at a stretching ratio of 3:1, and after the longitudinal stretching is completed, heating it to 170° C., heat setting it for 10 seconds, cooling it to 40° C., cooling it to form it, and obtaining a longitudinally stretched cast sheet;

[0097] (4) heating the longitudinally stretched cast sheet to 90° C., preheating for 10 seconds, heating it to 120° C., longitudinally stretching it at a stretching ratio of 3:1, heating it to 170° C., heat setting it for 10 seconds, cooling it to 110° C., cooling it to form it, and obtaining a rolling-resistant film layer with a thickness of 6 μm;

[0098] S2. Preparing a reinforced metal layer;

[0099] The anti-rolling film layer is placed in a vacuum evaporation chamber, and the high-purity aluminum wire in the metal evaporation chamber is melted and evaporated at a high temperature of 1400°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both sides of the surface of the polymer substrate layer to form a metal layer with a thickness of 1000nm; after taking out, an anti-rolling current collector is obtained.

[0100] Comparative Example 3

[0101] Comparative Example 3 provides a method for preparing a rolling-resistant current collector, comprising the following steps:

[0102] S1. Preparation of anti-rolling film layer;

[0103] (1) According to the mass percentage, 70.0wt% PET, 15.0wt% hydrogen bond cross-linked photoresponsive polymer (which is a linear azobenzene polymer containing hydrogen bonds PAB2-IPDI (M n-GPC ~18000), the polymer and its preparation method refer to CN111875765B), 15.0wt% acrylic acid, heated to 245℃ and melted, mixed, extruded, molded and sliced ​​to obtain polymer slices;

[0104] (2) placing the polymer slice in a crystallizer, heating it to 150°C, crystallizing it, keeping it warm for 40 minutes, transferring the polymer slice to a drying tower, heating it to 155°C, drying it for 140 minutes, heating the dried polymer slice to 270°C, extruding it through melt, and cooling it with a casting roller and water cooling to obtain a polymer casting sheet;

[0105] (3) heating the cast sheet to 90° C., preheating for 10 seconds, heating it to 110° C., longitudinally stretching it at a stretching ratio of 3:1, and after the longitudinal stretching is completed, heating it to 170° C., heat setting it for 10 seconds, cooling it to 40° C., cooling it to form it, and obtaining a longitudinally stretched cast sheet;

[0106] (4) heating the longitudinally stretched cast sheet to 90° C., preheating for 10 seconds, heating it to 120° C., longitudinally stretching it at a stretching ratio of 3:1, heating it to 170° C., heat setting it for 10 seconds, cooling it to 110° C., cooling it to form it, and obtaining a rolling-resistant film layer with a thickness of 6 μm;

[0107] S2. Preparing a reinforced metal layer;

[0108] The anti-rolling film layer is placed in a vacuum evaporation chamber, and the high-purity aluminum wire in the metal evaporation chamber is melted and evaporated at a high temperature of 1400°C. The evaporated metal atoms pass through the cooling system in the vacuum coating chamber and are deposited on both sides of the surface of the polymer substrate layer to form a metal layer with a thickness of 1000nm; after taking out, an anti-rolling current collector is obtained.

[0109] Test example:

[0110] Tensile strength: The tensile strength is tested according to the national standard GB / T 1040.3-2006.

[0111] Maximum deformation by rolling: 96g of active material NMC811, 2g of conductive agent carbon black and 2g of binder PVDF were added to 80g of NMP, and mixed evenly to obtain ternary positive electrode slurry. The ternary positive electrode slurry was evenly coated on the surface of the high temperature resistant composite current collector obtained above, dried, and rolled (rolling pressure was 60Mpa) to obtain the positive electrode sheet. The material was spread flat on the experimental table, and the height of the part with the largest bending degree was measured with a steel ruler.

[0112] Table 1

[0113]

[0114]

[0115] From the data given above, it can be seen that compared with Comparative Example 1, the positive electrode sheet prepared by adding the anti-rolling current collector of hydrogen-bonded cross-linked photoresponsive polymer and acrylic acid has a significantly stronger film tensile strength and a significantly reduced maximum rolling deformation. Compared with Comparative Examples 2 and 3, Examples 1 to 3 add appropriate amounts of hydrogen-bonded cross-linked photoresponsive polymer and acrylic acid, and the film tensile strength is significantly better than that of Comparative Examples 2 and 3, and the maximum rolling deformation is also significantly lower than that of Comparative Examples 2 and 3.

[0116] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "implementation", "specific implementation", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0117] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A rolling-resistant current collector, It is characterized in that It comprises an anti-rolling film layer and a metal layer, wherein the metal layer is located on at least one surface of the anti-rolling film layer; The anti-rolling film layer comprises a hydrogen-bond cross-linking photoresponsive polymer, a cross-linking agent and a high molecular material.

2. The rolling-resistant current collector according to claim 1, It is characterized in that The mass ratio of the hydrogen bond cross-linked photoresponsive polymer, the cross-linking agent and the polymer material is (2.5-10): (2.5-10): (80-95); Preferably, the mass ratio of the hydrogen-bond cross-linked photoresponsive polymer, the cross-linking agent and the polymer material is: (2.5-6): (2.5-6): (88-95).

3. The rolling-resistant current collector according to claim 1, It is characterized in that The hydrogen-bond cross-linked photoresponsive polymer is a linear azobenzene polymer containing hydrogen bonds; Optionally, the hydrogen-bond cross-linking photoresponsive polymer is obtained by addition polymerization of a diol containing an azobenzene group and a diisocyanate.

4. The rolling-resistant current collector according to claim 1, It is characterized in that The crosslinking agent is selected from at least one of acrylic acid, bis(4-chlorophenoxy) glucose, diethylene glycol diacrylate, N,N'-methylenebisacrylamide, and dihydroxyethyl phthalate; Optionally, the polymer material is selected from at least one of polypropylene, polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyimide, polypropylene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, polyphenylene sulfide, polyphenylene oxide, polystyrene and polyamide.

5. The rolling-resistant current collector according to claim 1, It is characterized in that The invention further comprises a substrate layer, wherein the anti-rolling film layer is located on at least one surface of the substrate layer; Optionally, the thickness of the anti-rolling film layer is 1 μm to 8 μm; The thickness of the metal layer is 100nm-1000nm.

6. The rolling-resistant current collector according to claim 1, It is characterized in that The anti-rolling film layer is formed by melting a hydrogen-bond cross-linked photoresponsive polymer, a cross-linking agent and a polymer material, and the anti-rolling film layer is prepared by the following method: The hydrogen-bond cross-linked photoresponsive polymer, the cross-linking agent and the polymer material are mixed, subjected to a first heating and melting process, and extruded to obtain a polymer slice; The polymer slices are subjected to a crystallization treatment at a predetermined temperature and a drying treatment, the dried polymer slices are subjected to a second heating and melting treatment, extruded into a cast sheet, and cooled to form a polymer cast sheet; The polymer casting sheet is heated to perform longitudinal stretching and transverse stretching and shaping to obtain the rolling-resistant film layer; Optionally, the temperature of the first heating and melting is 220 to 260 degrees Celsius; Optionally, the predetermined temperature is 130 to 180 degrees Celsius; Optionally, the temperature of the second heating and melting is 250 to 300 degrees Celsius; Optionally, the longitudinal stretching temperature is 100 to 130 degrees Celsius, and the stretching ratio is 2:1 to 4:1; Optionally, the temperature of the transverse stretching is 100 to 130 degrees Celsius, and the stretching ratio is 2:1 to 4:

1.

7. The rolling-resistant current collector according to claim 1, It is characterized in that The metal layer is prepared by the following method: Melting and evaporating the metal, cooling it, and allowing the evaporated metal atoms to be deposited on the surface of the anti-rolling film layer to obtain a metal layer, wherein the metal layer is deposited on at least one surface of the anti-rolling film layer; Optionally, the temperature of the melting and evaporation is 1200 to 1800 degrees Celsius.

8. An electrode sheet, It is characterized in that The invention comprises the anti-rolling current collector according to any one of claims 1 to 7, and an active material layer attached to at least one surface of the anti-rolling current collector.

9. A battery, It is characterized in that Comprising the electrode sheet as claimed in claim 8.

10. An electrical device, It is characterized in that A battery comprising the battery of claim 9.

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