Composite current collector having low thermal shrinkage rate and method of manufacturing the same and application

Abstract

The present application relates to a composite current collector having a low thermal shrinkage rate and a method for manufacturing the same and applications, wherein the composite current collector having a low thermal shrinkage rate comprises a polymer substrate layer and a conductive layer located on at least one surface of the polymer substrate layer; the polymer substrate layer comprises each component in parts by mass as follows: 0.1 to 3 parts of metal oxide fiber, 0.01 to 1 part of coupling agent, and 96 to 99.89 parts of polymer material. In the composite current collector having a low thermal shrinkage rate, a polymer substrate layer is used in which the composition consists of metal oxide fiber, coupling agent, and polymer material, and the polymer substrate layer has a relatively low thermal shrinkage rate, thereby preventing easy deformation when vacuum plating the metal conductive layer, thereby improving processing performance. The composite current collector having a low thermal shrinkage rate using the polymer substrate layer has a relatively low thermal shrinkage rate, thereby reducing the risk of the metal layer detaching due to the difference in thermal shrinkage rates between the polymer substrate layer and the metal layer in a high-temperature electrolyte environment.

Description

Technology Field

[0001] This application relates to the field of polymer materials technology, and in particular to a composite current collector having a low thermal shrinkage rate, a method for manufacturing the same, and applications. Background Technology

[0002] Lithium-ion batteries are being applied on a large scale in fields such as consumer electronics and electric vehicles, and the market has imposed higher requirements regarding aspects such as energy density, cycle life, and safety. Composite current collectors are novel current collectors generally manufactured by plating metal onto the surface of a polymer substrate layer, and they feature a "sandwich structure." Compared to pure metal current collectors, composite current collectors are characterized by lower weight and thinner thickness, leaving more space within the battery for the active material. The presence of the polymer substrate layer also enables the composite current collector to reduce the risk of temperature rise and thermal runaway, thereby improving battery safety.

[0003] However, due to the presence of the polymer substrate layer, the thermal shrinkage rate of the composite current collector is higher than that of conventional pure metal current collectors. In high-temperature electrolyte environments, conventional composite current collectors are prone to the detachment of the metal layer due to the difference in thermal shrinkage rates between the polymer substrate layer and the metal layer. Furthermore, this leads to a decrease in the conductivity performance of the composite current collector, thereby affecting battery performance.

[0004] Based on this, it is necessary to provide a composite current collector having a low thermal shrinkage rate, a method for manufacturing the same, and an application thereof. The composite current collector having a low thermal shrinkage rate has a relatively low thermal shrinkage rate, thereby reducing the risk of metal layer detachment caused by the difference in thermal shrinkage rates between the polymer substrate layer and the metal layer in a high-temperature electrolyte environment.

[0005] In a first aspect, the present application provides a composite current collector having a low thermal shrinkage rate, wherein the composite current collector having a low thermal shrinkage rate comprises a polymer substrate layer and a conductive layer located on at least one surface of the polymer substrate layer; and the polymer substrate layer comprises each of the following compositional parts by mass:

[0006] 0.1 to 3 parts of metal oxide fiber, 0.01 to 1 part of coupling agent and

[0007] Polymer materials in parts 96 to 99.89.

[0008] In some embodiments, the metal oxide fiber comprises one or more of Al2O3 fibers, ZrO2 fibers, MgO fibers, TiO2 fibers, ZnO fibers, and SnO2 fibers.

[0009] In some embodiments, the metal oxide fiber is a metal oxide nanofiber.

[0010] In some embodiments, the polymer material comprises one or more of polyethylene terephthalate, polyethylene, polypropylene, polyamide, polyimide, polyvinyl chloride, and polystyrene.

[0011] In some embodiments, the coupling agent comprises one or more of γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, maleic anhydride, and vinyltrimethoxysilane.

[0012] In one embodiment, the polymer substrate layer is a polymer substrate layer that has undergone thermal shrinkage.

[0013] In a second aspect, the present application provides a method for manufacturing a composite current collector having a low thermal shrinkage rate, and said method for manufacturing a composite current collector having a low thermal shrinkage rate, said method,

[0014] A step of preparing a polymer substrate layer by mixing and extruding metal oxide fibers having a mass part of 0.1 to 3 parts, a coupling agent having a mass part of 0.01 to 1 part, and a polymer material having a mass part of 96 to 99.89 parts;

[0015] The step of forming a conductive layer on at least one surface of the polymer substrate layer; is included.

[0016] In one embodiment thereof, the method further includes the step of performing a first heat shrinkage operation and / or a second heat shrinkage operation on the polymer substrate layer before the conductive layer is formed.

[0017] In one embodiment, the temperature of the first heat shrinkage operation is 100 to 200°C.

[0018] In one embodiment, the tension of the polymer substrate layer in the first heat shrinkage operation is 20 to 100 N.

[0019] In one embodiment thereof, during the first heat shrinkage operation, the polymer substrate layer is set under a tension of 0N-15N.

[0020] In one embodiment thereof, the first heat shrinkage operation is performed by unwinding with a tension of 20N to 100N.

[0021] In one embodiment, the tension of the polymer substrate layer in the second heat shrinkage operation is 50 to 250 N.

[0022] In one embodiment thereof, in the second heat shrinkage operation, one side of the polymer substrate layer passes through a high-temperature oven with a temperature of 1300-1500°C, and the other side is cooled by contacting a cooling roller with a cooling temperature of -35°C to 35°C.

[0023] In one embodiment thereof, in the second heat shrinkage operation, the polymer substrate layer is unwound at a speed of 100-800 m / min.

[0024] In a third aspect, the present application provides an electrode, said electrode comprising a composite current collector having any one of the low thermal shrinkage rates or a composite current collector having a low thermal shrinkage rate manufactured by a method for manufacturing any one of the composite current collectors having a low thermal shrinkage rate, and an electrode active material layer located on at least one surface of said current collector.

[0025] In a fourth aspect, the present application provides a battery, said battery comprising a composite current collector having any one of the low thermal shrinkage rates or a composite current collector having a low thermal shrinkage rate manufactured by a method for manufacturing any one of the composite current collectors having a low thermal shrinkage rate.

[0026] In a fifth aspect, the present application provides an electronic product, said electronic product includes said battery.

[0027] In the above-described composite current collector having a low thermal shrinkage rate, a polymer substrate layer comprising metal oxide fibers, a coupling agent, and a polymer material is used. Since the polymer substrate layer has a relatively low thermal shrinkage rate, it does not easily deform when vacuum plating the metal conductive layer, thereby improving processing performance. By having a relatively low thermal shrinkage rate, the composite current collector having a low thermal shrinkage rate using the above-described polymer substrate layer can reduce the risk of the metal layer detaching due to the difference in thermal shrinkage rates between the polymer substrate layer and the metal layer in a high-temperature electrolyte environment.

[0028] The above method for manufacturing a composite current collector having a low thermal shrinkage rate can reduce the risk of metal layer detachment caused by the difference in thermal shrinkage rates between the polymer substrate layer and the metal layer in a high-temperature electrolyte environment by manufacturing a composite current collector having a relatively low thermal shrinkage rate. Brief explanation of the drawing

[0029] FIG. 1 is a schematic flowchart of a method for manufacturing a composite current collector having a low thermal shrinkage rate provided in one embodiment of the present application. Specific details for implementing the invention

[0030] To make the above-mentioned objectives, features, and advantages of the present application clearer and easier to understand, specific embodiments of the present application are described in detail below in conjunction with the accompanying drawings. In the description below, many specific details have been described to facilitate a convenient and sufficient understanding of the present application. However, the present application may be practiced in many other ways than described herein, and since those skilled in the art may make similar developments without compromising the content and meaning of the present application, the present application is not limited to the specific embodiments disclosed below.

[0031] Unless otherwise defined, technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art to which this application pertains. These terms used herein are merely illustrative for describing this application and are not intended to limit it. The term "and / or" used herein means including any and all combinations of one or more of the listed items.

[0032] In one embodiment of the present application, a composite current collector having a low thermal shrinkage rate is provided, wherein the composite current collector having a low thermal shrinkage rate comprises a polymer substrate layer and a conductive layer located on at least one surface of the polymer substrate layer; and the polymer substrate layer comprises each of the following compositional parts by mass:

[0033] 0.1 to 3 parts of metal oxide fiber, 0.01 to 1 part of coupling agent and

[0034] It is a polymer material with a polymer content of 96 to 99.89 parts.

[0035] In the composite current collector having a low thermal shrinkage rate according to the present application, a polymer substrate layer comprising a metal oxide fiber, a coupling agent, and a polymer material is used. Since the polymer substrate layer has a relatively low thermal shrinkage rate, it does not easily deform when vacuum plating the metal conductive layer, thereby improving processing performance. By having a relatively low thermal shrinkage rate, the composite current collector having a low thermal shrinkage rate using the polymer substrate layer can reduce the risk of the metal layer detaching due to the difference in thermal shrinkage rates between the polymer substrate layer and the metal layer in a high-temperature electrolyte environment.

[0036] In some embodiments, the metal oxide fibers include one or more of Al2O3 fibers, ZrO2 fibers, MgO fibers, TiO2 fibers, ZnO fibers, and SnO2 fibers.

[0037] In some embodiments, the metal oxide fibers are metal oxide nanofibers. The improvement effect of the nanofibers on the thermal shrinkage rate of polymer materials is relatively excellent.

[0038] In some embodiments, the diameter of the metal oxide nanofiber is less than or equal to 1000 nm.

[0039] In some embodiments, the polymer material comprises one or more of polyethylene terephthalate, polyethylene, polypropylene, polyamide, polyimide, polyvinyl chloride, and polystyrene.

[0040] In some embodiments, the coupling agent comprises one or more of γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, maleic anhydride, and vinyltrimethoxysilane.

[0041] In one embodiment, the polymer substrate layer is a polymer substrate layer that has undergone thermal shrinkage. By performing a pre-thermal shrinkage treatment on the polymer substrate layer during the processing stage, a relatively low thermal shrinkage rate can be achieved during actual use, thereby reducing the risk of metal layer detachment during use.

[0042] In one of the embodiments, the polymer substrate layer comprises each compositional component in the following mass percentages:

[0043] 0.1% to 3% of metal oxide fibers, 0.01% to 1% of coupling agent and

[0044] It is a polymer material of 96% to 99.89%.

[0045] In one of the embodiments, the raw material of the polymer substrate layer is each compositional component in the following mass percentages:

[0046] 0.1% to 3% of metal oxide fibers, 0.01% to 1% of coupling agent and

[0047] It is a polymer material of 96% to 99.89%.

[0048] Referring to FIG. 1, another embodiment of the present application provides a method for manufacturing a composite current collector having a low thermal shrinkage rate, and the method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0049] Step (S101): A polymer substrate layer is prepared by mixing and extruding, respectively, metal oxide fibers having a mass part of 0.1 to 3 parts, a coupling agent having a mass part of 0.01 to 1 part, and a polymer material having a mass part of 96 to 99.89 parts;

[0050] Step (S102): A conductive layer is formed on at least one surface of a polymer substrate layer.

[0051] The above method for manufacturing a composite current collector having a low thermal shrinkage rate can reduce the risk of metal layer detachment caused by the difference in thermal shrinkage rates between the polymer substrate layer and the metal layer in a high-temperature electrolyte environment by manufacturing a composite current collector having a relatively low thermal shrinkage rate.

[0052] In one embodiment thereof, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0053] Step (1): A polymer substrate layer is prepared by mixing and extruding, respectively, metal oxide fibers having a mass part of 0.1 to 3 parts, a coupling agent having a mass part of 0.01 to 1 part, and a polymer material having a mass part of 96 to 99.89 parts;

[0054] Step (2): A conductive layer is formed on at least one surface of the polymer substrate layer.

[0055] In one embodiment, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps.

[0056] Step (1): A polymer substrate layer is prepared by mixing and extruding, respectively, a metal oxide fiber having a mass percentage of 0.1% to 3%, a coupling agent having a mass percentage of 0.01% to 1%, and a polymer material having a mass percentage of 96% to 99.89%;

[0057] Step (2): A conductive layer is formed on at least one surface of the polymer substrate layer.

[0058] In one embodiment, the process further includes performing a heat shrinkage operation on the polymer substrate layer before forming the conductive layer. By performing a preliminary heat shrinkage treatment on the polymer substrate layer during the processing process, a relatively low heat shrinkage rate can be achieved during actual use, thereby reducing the risk of metal layer detachment during use.

[0059] In one embodiment, the temperature of the heat shrinkage operation is 100 to 200°C, the polymer substrate film is set in place during the heat shrinkage operation, and the tension of the polymer substrate layer during the heat shrinkage operation is 0N to 15N. Within the temperature range of the heat shrinkage operation, the pre-shrinkage range of the polymer substrate layer is suitable so as not only to avoid affecting subsequent processing and use, but also to enable the manufactured composite current collector to have a relatively low heat shrinkage rate. Optionally, the temperature of the heat shrinkage operation is 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C.

[0060] In another embodiment, the temperature of the heat shrinkage operation is 100 to 200°C, and during the heat shrinkage process, the polymer substrate film is stretched and transported with a tension of 20 to 100 N, and the tension is the tension of the polymer substrate layer at the heat shrinkage temperature, and under the tension conditions, the shrinkage effect can be ensured and production efficiency can be ensured. Optionally, the temperature of the heat shrinkage operation is 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C. Within the tension range of the polymer substrate layer during the heat shrinkage process, the pre-shrinkage range of the polymer substrate layer is suitable, so that not only is it not affected for subsequent processing and use, but the manufactured composite current collector can also have a relatively low heat shrinkage rate. Optionally, the tensile strength of the polymer substrate layer during the heat shrinkage process is 20N, 30N, 40N, 50N, 60N, 70N, 80N, 90N, or 100N.

[0061] In another embodiment, in the step of performing a second heat shrinkage operation on the polymer substrate layer, during the second heat shrinkage operation, the polymer substrate layer is unwound at a speed of 100-800 m / min, one side of the polymer substrate layer passes through a high-temperature oven with a temperature of 1300-1500°C, and the other side is cooled by contacting a cooling roller with a cooling temperature of -35°C to 35°C. During the second heat shrinkage operation, the tension of the polymer substrate layer is 50 to 250 N, and under these conditions, not only is it not affected for subsequent processing use, but the manufactured composite current collector can also have a relatively low heat shrinkage rate, and production efficiency can also be effectively improved under these tension conditions. Optionally, in the second heat shrinkage process, the unwinding speed is 100 m / min, 200 m / min, 300 m / min, 400 m / min, 500 m / min, 600 m / min, 700 m / min, or 800 m / min, and the high oven temperature is 1300°C, 1400°C, or 1500°C. The cooling temperature is -35°C, -25°C, -15°C, -5°C, 0°C, 5°C, 15°C, 25°C, or 35°C, and the tensile strength of the polymer substrate layer is 50 N, 101 N, 120 N, 140 N, 160 N, 180 N, 200 N, 220 N, 230 N, or 250 N.

[0062] The above polymer substrate layer may undergo only a first heat shrinkage operation (referred to as "heat shrinkage operation"), may perform only a second heat shrinkage operation without undergoing the first heat shrinkage operation, or may perform a second heat shrinkage operation after performing the first heat shrinkage operation. The second heat shrinkage operation may be performed before the conductive layer is formed, or it may be performed during the process of forming the conductive layer, for example, in an aluminum plating facility.

[0063] After the polymer substrate layer undergoes a first and / or second thermal shrinkage operation, the thermal shrinkage rate after the conductive layer is formed on the surface of the polymer substrate layer is smaller than the thermal shrinkage rate after the conductive layer is formed on the surface of the polymer substrate layer that has not undergone the thermal shrinkage operation.

[0064] In one embodiment, the conductive layer is manufactured by physical vapor deposition.

[0065] In one embodiment, the conductive layer is manufactured by magnetron sputtering or vacuum deposition.

[0066] In one embodiment, a conductive layer is formed by depositing it on the surface of a polymer substrate film through a vacuum deposition method by heating the deposition material to cause it to evaporate.

[0067] In one embodiment thereof, the material of the conductive layer comprises one or more of copper, copper alloy, aluminum, aluminum alloy, nickel, nickel alloy, titanium, and silver.

[0068] In one embodiment, the thickness of the polymer substrate layer is 2 to 20 μm. Optionally, the thickness of the polymer substrate layer is 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, or 20 μm.

[0069] In one embodiment, the thickness of the conductive layer is 0.5 to 2 μm. Optionally, the thickness of the conductive layer is 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, 1.5 μm, 1.6 μm, 1.7 μm, 1.8 μm, 1.9 μm, or 2 μm.

[0070] In one embodiment thereof, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0071] Step (1): A polymer substrate layer is prepared by mixing and extruding a metal oxide fiber having a mass of 0.1 to 3 parts, a coupling agent having a mass of 0.01 to 1 part, and a polymer material having a mass of 96 to 99.89 parts, respectively;

[0072] Step (2): A heat shrinkage operation is performed on the polymer substrate layer, the temperature of the heat shrinkage operation is 100 to 200°C, and the tension of the polymer substrate layer during the heat shrinkage operation is 20 to 100 N;

[0073] Step (3): A conductive layer is formed on at least one surface of the polymer substrate layer after the heat shrinkage process.

[0074] In one embodiment thereof, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0075] Step (1): A polymer substrate layer is prepared by mixing and extruding metal oxide fibers having a mass percentage of 0.1% to 3%, a coupling agent having 0.01% to 1%, and a polymer material having 96% to 99.89%;

[0076] Step (2): A heat shrinkage operation is performed on the polymer substrate layer, the temperature of the heat shrinkage operation is 100 to 200°C, and the tension of the polymer substrate layer during the heat shrinkage operation is 20 to 100 N;

[0077] Step (3): A conductive layer is formed on at least one surface of the polymer substrate layer after the heat shrinkage process.

[0078] In one embodiment thereof, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0079] Step (1): A polymer substrate layer is prepared by mixing and extruding metal oxide fibers having a mass percentage of 0.1% to 3%, a coupling agent having 0.01% to 1%, and a polymer material having 96% to 99.89%;

[0080] Step (2): A heat shrinkage operation is performed on the polymer substrate layer, the temperature of the heat shrinkage operation is 100 to 200°C, the polymer substrate layer is set in place during the heat shrinkage operation, and the tension of the polymer substrate layer is 0 N to 15 N;

[0081] Step (3): A conductive layer is formed on at least one surface of the polymer substrate layer after the heat shrinkage process.

[0082] In one embodiment thereof, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0083] Step (1): A polymer substrate layer is prepared by mixing and extruding metal oxide fibers having a mass percentage of 0.1% to 3%, a coupling agent having 0.01% to 1%, and a polymer material having 96% to 99.89%;

[0084] Step (2): A heat shrinkage operation is performed on the polymer substrate layer, the temperature of the heat shrinkage operation is 100 to 200°C, and the tension of the polymer substrate layer during the heat shrinkage operation is 20 to 100 N;

[0085] Step (3): A conductive layer is formed on at least one surface of the polymer substrate layer after the heat shrinkage process.

[0086] In one embodiment thereof, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0087] Step (1): A polymer substrate layer is prepared by mixing and extruding metal oxide fibers having a mass percentage of 0.1% to 3%, a coupling agent having 0.01% to 1%, and a polymer material having 96% to 99.89%;

[0088] Step (2): A first heat shrinkage operation is performed on the polymer substrate layer, the temperature of the first heat shrinkage operation is 100 to 200°C, and the tension of the polymer substrate layer during the heat shrinkage operation is 20 to 100 N;

[0089] Step (3): A second heat shrinkage operation is performed on the polymer substrate layer, wherein the polymer substrate layer is unwound at a speed of 100-800 m / min, one side of the polymer substrate layer passes through a high-temperature oven with a temperature of 1300-1500℃, and the other side is cooled by contacting a cooling roller with a cooling temperature of -35℃ to 35℃, and the tension of the polymer substrate layer in the second heat shrinkage operation is 50-250N;

[0090] Step (4): A conductive layer is formed on at least one surface of the polymer substrate layer after the first and second heat shrinkage operations.

[0091] In one embodiment thereof, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0092] Step (1): A polymer substrate layer is prepared by mixing and extruding metal oxide fibers having a mass percentage of 0.1% to 3%, a coupling agent having 0.01% to 1%, and a polymer material having 96% to 99.89%;

[0093] Step (2): A first heat shrinkage operation is performed on the polymer substrate layer, the temperature of the first heat shrinkage operation is 100 to 200°C, and the tension of the polymer substrate layer during the heat shrinkage operation is 20 to 100 N;

[0094] Step (3): A second heat shrinkage operation is performed on the polymer substrate layer, wherein the polymer substrate layer is unwound at a speed of 100-800 m / min, one side of the polymer substrate layer passes through a high-temperature oven with a temperature of 1300-1500℃, and the other side is cooled by contacting a cooling roller with a cooling temperature of -35℃ to 35℃, and the tension of the polymer substrate layer in the second heat shrinkage operation is 50-250N;

[0095] Step (4): Simultaneously with the second heat shrinkage operation, a conductive layer is formed on at least one surface of the polymer substrate layer.

[0096] In one embodiment thereof, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0097] Step (1): A polymer substrate layer is prepared by mixing and extruding metal oxide fibers having a mass percentage of 0.1% to 3%, a coupling agent having 0.01% to 1%, and a polymer material having 96% to 99.89%;

[0098] Step (2): A second heat shrinkage operation is performed on the polymer substrate layer, wherein the polymer substrate layer is unwound at a speed of 100-800 m / min, one side of the polymer substrate layer passes through a high-temperature oven with a temperature of 1300-1500℃, and the other side is cooled by contacting a cooling roller with a cooling temperature of -35℃ to 35℃, and the tension of the polymer substrate layer in the second heat shrinkage operation is 50-250N;

[0099] Step (3): A conductive layer is formed on at least one surface of the polymer substrate layer after the second heat shrinkage operation.

[0100] In one embodiment thereof, a method for manufacturing a composite current collector having a low thermal shrinkage rate comprises the following steps:

[0101] Step (1): A polymer substrate layer is prepared by mixing and extruding metal oxide fibers having a mass percentage of 0.1% to 3%, a coupling agent having 0.01% to 1%, and a polymer material having 96% to 99.89%;

[0102] Step (2): A second heat shrinkage operation is performed on the polymer substrate layer, wherein the polymer substrate layer is unwound at a speed of 100-800 m / min, one side of the polymer substrate layer passes through a high-temperature oven with a temperature of 1300-1500℃, and the other side is cooled by contacting a cooling roller with a cooling temperature of -35℃ to 35℃, and the tension of the polymer substrate layer in the second heat shrinkage operation is 50-250N;

[0103] Step (3): Simultaneously with the second heat shrinkage operation, a conductive layer is formed on at least one surface of the polymer substrate layer.

[0104] In a third aspect, the present application provides an electrode, said electrode comprising a composite current collector having any one of the low thermal shrinkage rates or a composite current collector having a low thermal shrinkage rate manufactured by a method for manufacturing any one of the composite current collectors having a low thermal shrinkage rate, and an electrode active material layer located on at least one surface of said current collector.

[0105] In a fourth aspect, the present application provides a battery, said battery comprising a composite current collector having any one of the low thermal shrinkage rates or a composite current collector having a low thermal shrinkage rate manufactured by a method for manufacturing any one of the composite current collectors having a low thermal shrinkage rate.

[0106] In a fifth aspect, the present application provides an electronic product, said electronic product includes said battery.

[0107] The following is a specific example.

[0108] Example 1

[0109] Manufacture of a composite current collector having a low thermal shrinkage rate:

[0110] Step (1): 0.01 kg of silane coupling agent KH550 is added to 0.1 kg of Al2O3 and uniformly stirred to obtain a mixture; the mixture is mixed with 99.89 kg of PET particles and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0111] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 150℃ and the polymer substrate film tension is 50N;

[0112] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0113] Example 2

[0114] Manufacture of a composite current collector having a low thermal shrinkage rate:

[0115] Step (1): 0.03 kg of silane coupling agent KH550 is added to 0.3 kg of Al2O3 and uniformly stirred to obtain a mixture; the mixture is mixed with 99.67 kg of PET particles and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0116] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 150℃ and the polymer substrate film tension is 50N;

[0117] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0118] Example 3

[0119] Manufacture of a composite current collector having a low thermal shrinkage rate:

[0120] Step (1): 0.06 kg of silane coupling agent KH550 is added to 0.3 kg of Al2O3 and 0.3 kg of MgO and uniformly stirred to obtain a mixture; the mixture is mixed with 99.34 kg of PET particles and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0121] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 150℃ and the polymer substrate film tension is 50N;

[0122] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0123] Example 4

[0124] Manufacture of a composite current collector having a low thermal shrinkage rate:

[0125] Step (1): 0.1 kg of silane coupling agent KH550 is added to 1 kg of Al2O3 and uniformly stirred to obtain a mixture; the mixture is mixed with 98.9 kg of PET particles and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0126] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 150℃ and the polymer substrate film tension is 50N;

[0127] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0128] Example 5

[0129] Manufacture of a composite current collector having a low thermal shrinkage rate:

[0130] Step (1): 0.3 kg of silane coupling agent KH550 is added to 3 kg of Al2O3 and uniformly stirred to obtain a mixture; the mixture is mixed with 96.7 kg of PET particles and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0131] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 150℃ and the polymer substrate film tension is 50N;

[0132] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0133] Example 6

[0134] Manufacture of a composite current collector having a low thermal shrinkage rate:

[0135] Step (1): 0.01 kg of silane coupling agent KH550 is added to 0.1 kg of Al2O3 and uniformly stirred to obtain a mixture; the mixture is mixed with 99.89 kg of PET particles and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0136] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 100℃ and the polymer substrate film tension is 50N;

[0137] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0138] Example 7

[0139] Manufacture of a composite current collector having a low thermal shrinkage rate:

[0140] Step (1): 0.03 kg of silane coupling agent KH550 is added to 0.3 kg of Al2O3 and uniformly stirred to obtain a mixture; the mixture is mixed with 99.67 kg of PET particles and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0141] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 150℃ and the polymer substrate film tension is 50N;

[0142] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0143] Example 8

[0144] Manufacture of a composite current collector having a low thermal shrinkage rate:

[0145] Step (1): 0.06 kg of silane coupling agent KH550 is added to 0.3 kg of Al2O3 and 0.3 kg of MgO and uniformly stirred to obtain a mixture; the mixture is mixed with 99.34 kg of PET particles and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0146] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 150℃ and the polymer substrate film tension is 20N;

[0147] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0148] Example 9

[0149] Manufacture of a composite current collector having a low thermal shrinkage rate:

[0150] Step (1): 0.1 kg of silane coupling agent KH550 is added to 1 kg of Al2O3 and uniformly stirred to obtain a mixture; the mixture is mixed with 98.9 kg of PET particles and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0151] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 150℃ and the polymer substrate film tension is 100N;

[0152] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0153] Comparative Example 1

[0154] Manufacture of composite current collectors:

[0155] Step (1): 100 kg of PET particles are mixed and uniformly stirred, and then extruded and stretched using a twin-screw extruder to form a film, thereby obtaining a polymer substrate film with a thickness of 8 μm;

[0156] Step (2): After unwinding the polymer substrate film obtained in Step (1), heat shrinkage is performed in an oven, and then rewinding is performed, the oven temperature is 150℃ and the polymer substrate film tension is 50N;

[0157] Step (3): A composite current collector is obtained by forming a 1 μm conductive layer on each of the two surfaces of the polymer substrate film that was pre-shrinked in Step (2) through physical vapor deposition, wherein the conductive layer is made of aluminum.

[0158] Comparative Example 2

[0159] It is basically the same as Example 1, but the difference is that the polymer substrate film has not undergone heat shrinkage treatment.

[0160] The mass percentages of the silane coupling agent KH550, metal oxide fibers, and PET particles, and the temperature and tension data of the heat shrinkage operation in Examples 1 to 9 and Comparative Examples 1 to 2 are as shown in Table 1 below.

[0161]

[0162] Tensile strength tests and thermal shrinkage rate tests were performed on the composite current collectors prepared in Examples 1 to 9 and Comparative Examples 1 to 2, and the test methods are as follows.

[0163] (1) Tensile strength test: The tensile speed is 50 mm / min, and five samples are taken from each example or comparative example, and the average value is taken as the test result. During the test, the longitudinal direction and the clamp axis must be parallel, and the straight shape of the sample must be maintained. If the sample breaks within the clamp jaw or if there is a notch on the edge of the sample, the test result of that sample is invalid.

[0164] (2) Thermal shrinkage rate test: A specimen of 100 mm * 100 mm is cut using a sample cutting plate, and the length L0 of MD (longitudinal) and TD (transverse) is measured. Then, the specimen is baked at 150°C for 30 minutes, and the length L1 is recorded. The thermal shrinkage rate is T = (L0 - L1) / L0 * 100. The test results are shown in Table 2 below.

[0165]

[0166] As can be seen by comparing the test results, compared to a composite current collector using only PET as the polymer substrate layer, the composite current collectors prepared in Examples 1 to 9 have relatively low thermal shrinkage rates in both the transverse and longitudinal directions.

[0167] As can be seen by comparing Example 1 and Comparative Example 1, the thermal shrinkage rate of a polymer substrate film that has not undergone a thermal shrinkage process and has a conductive layer prepared by physical vapor deposition is greater than the sum of the thermal shrinkage rates of a polymer substrate film that has undergone a thermal shrinkage process and has a conductive layer deposited.

[0168] Each technical feature of the embodiments according to the above may be combined arbitrarily, and for the sake of brevity of description, not all possible combinations of technical features are described in the embodiments; however, as long as there is no contradiction in such combinations of technical features, they should all be deemed to be included within the scope described herein.

[0169] The above embodiments are merely some embodiments of the present application, and while the description is relatively specific and detailed, it should not be understood as a limitation to the claims of the present invention. Those skilled in the art may make various modifications and improvements without departing from the spirit of the present application, and all such modifications and improvements should be included in the claims of the present application. Accordingly, the claims of the present application are determined according to the appended claims, and the specification and the attached drawings may be used to interpret the claims.

Claims

Claim 1 A composite current collector having a low thermal shrinkage rate, comprising a polymer substrate layer and a conductive layer located on at least one surface of the polymer substrate layer; wherein the polymer substrate layer comprises each of the following compositional parts by mass: 0.1 to 3 parts of metal oxide fiber, 0.01 to 1 part of coupling agent, and 96 to 99.89 parts of polymer material; wherein the metal oxide fiber satisfies at least one of the following features: (1) the metal oxide fiber comprises one or more of Al2O3 fiber, ZrO2 fiber, MgO fiber, TiO2 fiber, ZnO fiber, and SnO2 fiber; (2) the metal oxide fiber is a metal oxide nanofiber; and wherein the polymer material comprises one or more of polyethylene terephthalate, polyethylene, polypropylene, polyamide, polyimide, polyvinyl chloride, and polystyrene; and wherein the polymer substrate layer is a polymer substrate layer that has undergone a first thermal shrinkage operation and / or a second thermal shrinkage operation. Claim 2 A composite current collector having a low thermal shrinkage rate according to claim 1, characterized in that the coupling agent comprises one or more of γ-aminopropyltriethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, maleic anhydride, and vinyltrimethoxysilane. Claim 3 A method for manufacturing a composite current collector having a low thermal shrinkage rate according to claim 1, comprising: a step of manufacturing a polymer substrate layer by mixing and extruding a metal oxide fiber having a mass part of 0.1 to 3 parts, a coupling agent having a mass part of 0.01 to 1 part, and a polymer material having a mass part of 96 to 99.89 parts; a step of forming a conductive layer on at least one surface of the polymer substrate layer; and further comprising a step of performing a first thermal shrinkage operation and / or a second thermal shrinkage operation on the polymer substrate layer before the conductive layer is formed. Claim 4 A method for manufacturing a composite current collector having a low thermal shrinkage rate, wherein, in claim 3, the first thermal shrinkage operation satisfies at least one of the following features: (1) the temperature of the first thermal shrinkage operation is 100 to 200°C; (2) in the first thermal shrinkage operation, the polymer substrate layer is set at a tension of 0 N to 15 N or unwound at a tension of 20 N to 100 N. Claim 5 A method for manufacturing a composite current collector having a low thermal shrinkage rate, wherein, in claim 3, the second thermal shrinkage operation has the following features: (1) in the second thermal shrinkage operation, the polymer substrate layer is unwound at a speed of 100-800 m / min; (2) in the second thermal shrinkage operation, one side of the polymer substrate layer passes through a high-temperature oven with a temperature of 1300-1500℃, and the other side is cooled by contacting a cooling roller with a cooling temperature of -35℃ to 35℃; (3) in the second thermal shrinkage operation, the tension of the polymer substrate layer is 50-250N; and at least one of these is satisfied. Claim 6 A electrode piece characterized by comprising a composite current collector having a low thermal shrinkage rate according to claim 1 or a composite current collector having a low thermal shrinkage rate manufactured by a method for manufacturing a composite current collector having a low thermal shrinkage rate according to claim 3, and an active material layer located on at least one surface of said current collector. Claim 7 A battery characterized by including an electrode according to claim 6. Claim 8 An electronic product characterized by including a battery according to claim 7. Claim 9 delete Claim 10 delete Claim 11 delete Claim 12 delete

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