Composite current collector, electrode sheet, electrode assembly, secondary battery and electric apparatus

Abstract

A composite current collector (100), an electrode sheet, an electrode assembly (413), a secondary battery (410) and an electric apparatus. Exhaust units (31) penetrating through a conductive layer (30) are provided on the conductive layer (30), so that during preparation, the conductive layer (30) is bonded to a substrate (10), and the conductive layer (30) is pressed. Since the exhaust units (31) are provided on the conductive layer (30), residual gas in a glue will be exhausted from the exhaust units (31) during pressing, so that the conductive layer (30) and the substrate (10) are fully adhered to each other, thereby improving the bonding strength between the conductive layer (30) and the substrate (10), and effectively reducing the falling risk of the conductive layer (30). Moreover, during pressing, part of the glue permeates into the exhaust units (31), so as to enhance the adhesion strength, so that the conductive layer (30) and the substrate (10) are tightly bonded, thereby improving the stability of the structure of the composite current collector (100).

Description

Composite current collector, pole piece, electrode assembly, secondary battery and electrical device

[0001] Related applications

[0002] This application claims priority to Chinese patent application number 2024200415831, filed on January 8, 2024, entitled “Composite current collector, pole piece, electrode assembly, secondary battery and electrical device,” the entire text of which is hereby incorporated by reference. Technical Field

[0003] The present application relates to the field of battery technology, and in particular to a composite current collector, a pole piece, an electrode assembly, a secondary battery, and an electrical device. Background Art

[0004] The current collector is an important component of the battery. It not only provides support for the active material layer, but also collects the current generated by the active material layer for external output. With the improvement of battery reliability requirements, composite current collectors have also been proposed. Composite current collectors refer to the structure obtained by combining a conductive layer and a polymer layer. If the conductive layer and the polymer layer are bonded by glue, there is a risk that the conductive layer on the surface will fall off.

[0005] The above statements are only used to provide background information related to the present application and do not necessarily constitute prior art.

[0006] Summary of the Invention

[0007] Based on this, it is necessary to provide a composite current collector, a pole piece, an electrode assembly, a secondary battery and an electrical device to address the problem that the conductive layer on the surface of the composite current collector is at risk of falling off due to bonding with glue.

[0008] In a first aspect, the present application provides a composite current collector, comprising: a substrate; a conductive layer bonded to at least one side of the substrate; wherein an exhaust unit is provided on the conductive layer, and at least part of the exhaust unit penetrates the conductive layer in the thickness direction of the composite current collector.

[0009] The above-mentioned composite current collector is provided with a venting unit that runs through the conductive layer, so that during the preparation process, the conductive layer is bonded to the substrate and the conductive layer is pressed. Since the conductive layer has a venting unit, the gas remaining in the glue during the pressing process will be discharged from the venting unit, so that the conductive layer and the substrate are fully adhered, the bonding strength between the conductive layer and the substrate is improved, and the probability of the conductive layer falling off is effectively reduced. At the same time, during the pressing process, part of the glue will penetrate into the venting unit, enhancing the adhesion strength, so that the conductive layer and the substrate are tightly bonded, thereby improving the stability of the composite current collector structure.

[0010] In some embodiments, multiple exhaust units are provided, spaced apart on the conductive layer. Sealing multiple exhaust units on the conductive layer increases the exhaust range, effectively reducing residual gas between the conductive layer and the substrate, and improving the bonding strength between the conductive layer and the substrate. Furthermore, the multiple exhaust units also serve as penetration points for glue, further enhancing the bonding strength between the conductive layer and the substrate.

[0011] In some embodiments, the distribution density of the exhaust units on the conductive layer is denoted as n, where 1 unit / dm 2 ≤n≤100 pieces / dm 2 This design controls the distribution density of the exhaust unit to 1 / dm 2 ~100 pieces / dm 2 It can effectively take into account both the exhaust effect and the structural strength of the conductive layer.

[0012] In some embodiments, the distribution density n also satisfies the following conditions: 4 / dm 2 ≤n≤25 pieces / dm 2 In this way, the distribution density is further limited to 4 / dm 2 ~25 pieces / dm 2 While ensuring effective exhaust, the number of holes or grooves on the conductive layer is minimized, so that the conductive layer has a certain structural strength and the overall structural stability of the composite current collector is improved.

[0013] In some embodiments, the exhaust cells are spaced apart in the first direction to form multiple groups of cell rows, and the exhaust cells in each group of cell rows are spaced apart along the second direction. In at least one adjacent group of cell rows, the exhaust cells in one group of cell rows are staggered in the first direction from the exhaust cells in the other group of cell rows, the first direction intersects the second direction, and the plane formed by them intersects the thickness direction. With this design, the exhaust cells in at least one adjacent group of cell rows are staggered in the first direction, so that the force applied to the conductive layer in the first direction is not simultaneously concentrated on the exhaust cells in each group of cell rows, thereby better alleviating the tensile strength and tensile elongation of the conductive layer. Furthermore, due to the staggered distribution, the exhaust cells between the two adjacent groups of cell rows can be arranged closer together, resulting in a larger exhaust range and a more uniform exhaust effect.

[0014] In some embodiments, the spacing between two adjacent exhaust units in each unit row is denoted as X, where 10 mm ≤ X ≤ 100 mm. This design maintains the spacing between two adjacent exhaust units between 10 mm and 100 mm. This rationally controls the spacing between the exhaust units, ensuring that the conductive layer maintains a certain structural strength in the second direction and that gas is uniformly exhausted in the second direction during lamination.

[0015] In some embodiments, the spacing X further satisfies the condition: 20 mm ≤ X ≤ 50 mm. With this design, the spacing between two adjacent exhaust units in the second direction is further controlled to be between 20 mm and 50 mm, so that the structural design of the conductive layer can more effectively balance structural strength and gas exhaust efficiency.

[0016] In some embodiments, the spacing in the first direction between the exhaust cells in one adjacent cell row and the corresponding exhaust cells in the other adjacent cell row is denoted as Z, where 0 mm ≤ Z ≤ 100 mm. This design controls the spacing in the first direction between two adjacent exhaust cells to be between 0 mm and 100 mm. This rationally controls the spacing between the exhaust cells, ensuring that the conductive layer maintains a certain structural strength in the first direction and that gas is uniformly exhausted in the first direction during lamination.

[0017] In some embodiments, the spacing Z further satisfies the condition: 20 mm ≤ Z ≤ 50 mm. With this design, the spacing between two adjacent exhaust units in the first direction is further controlled to be between 20 mm and 50 mm, so that the structural design of the conductive layer can more effectively balance structural strength and gas exhaust efficiency.

[0018] In some embodiments, the first direction is configured as the length direction of the conductive layer, and the second direction is configured as the width direction of the conductive layer. This design, which controls the first direction as the length direction, facilitates the processing of exhaust units in rows along the length direction; it also facilitates staggering in the length direction, alleviating the tensile strength and elongation of the conductive layer in the length direction.

[0019] In some embodiments, the venting unit is arranged with its penetration direction inclined relative to the thickness direction. Designing the venting unit with an inclined structure can extend its extension length on the conductive layer, effectively reducing the glue's penetration from the venting unit to the outer surface of the conductive layer. Furthermore, glue that penetrates the inclined venting unit is subjected to an upward force from the inner wall of the venting unit, effectively reducing the chance of it falling off, strengthening the bonding force, and improving the overall structural strength of the composite current collector.

[0020] In some embodiments, an acute angle θ is formed between the through-direction and the thickness direction of the vent unit, where 30°≤θ≤80°. By controlling the acute angle θ between 30° and 80°, the vent unit can be more accurately tilted on the conductive layer, thereby reducing the risk of glue penetrating the vent unit to the outer surface of the conductive layer.

[0021] In some embodiments, the acute angle θ further satisfies the condition: 50°≤θ≤70°. By controlling the acute angle θ between 50° and 70°, the exhaust unit can maintain a certain tilt on the conductive layer while reducing the difficulty of manufacturing the exhaust unit, effectively achieving both glue overflow prevention and processing convenience.

[0022] In some embodiments, the venting unit is constructed as a circular hole, with a diameter of D1, where 1 nm ≤ D1 ≤ 5000 nm. This design, which controls the diameter of the venting unit to between 1 nm and 5000 nm, reduces the risk of gel runoff during composite current collector preparation and facilitates venting between the conductive layer and the substrate, improving the bonding strength between the two.

[0023] In some embodiments, the diameter D1 further satisfies the condition: 50 nm ≤ D1 ≤ 300 nm. With this design, the diameter of the exhaust unit is controlled between 50 nm and 300 nm, making the exhaust unit design more effective in balancing the anti-escape effect and the exhaust effect.

[0024] In some embodiments, an adhesive layer is provided between the conductive layer and the substrate, and one end of the vent unit extends to a side of the conductive layer facing the adhesive layer. By not extending the vent unit to the adhesive layer but rather providing it on the conductive layer, damage to the adhesive layer can be reduced, thereby improving the bonding strength between the structures.

[0025] In some embodiments, the thickness of the glue layer in the thickness direction is denoted as D2, where 200 nm ≤ D2 ≤ 1500 nm. Thus, the glue layer thickness is controlled between 200 nm and 1500 nm to minimize the amount of glue used while ensuring effective bonding and controlling the thickness of the composite current collector.

[0026] In some embodiments, the thickness D2 further satisfies the condition: 300 nm ≤ D2 ≤ 700 nm. Thus, the thickness of the adhesive layer is controlled between 300 nm and 700 nm, further effectively balancing the bonding strength and the investment cost of the composite current collector.

[0027] In some embodiments, the thickness of the substrate in the thickness direction is denoted as D3, where 2 μm ≤ D3 ≤ 10 μm. Thus, by controlling the substrate thickness between 2 μm and 10 μm, the overall thickness of the composite current collector can be reduced while maintaining structural strength, thereby increasing the energy density of the battery.

[0028] In some embodiments, the thickness D3 further satisfies the condition: 3 μm ≤ D3 ≤ 8 μm. Thus, controlling the substrate thickness between 3 μm and 8 μm allows the prepared composite current collector to more effectively balance structural strength and thickness.

[0029] In a second aspect, the present application provides a pole piece, which includes any of the composite current collectors described above.

[0030] In a third aspect, the present application provides an electrode assembly, which includes the above-mentioned electrode piece.

[0031] In a fourth aspect, the present application provides a secondary battery, which includes the above electrode assembly.

[0032] In a fifth aspect, the present application provides an electrical device, which includes the above secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the drawings without creative work.

[0034] FIG1 is a schematic structural diagram of a vehicle provided in some embodiments of the present application.

[0035] FIG2 is a schematic diagram of the exploded structure of a secondary battery provided in some embodiments of the present application.

[0036] FIG3 is a cross-sectional view of a composite current collector structure provided in some embodiments of the present application.

[0037] FIG4 is a first schematic diagram of the distribution structure of the exhaust units on the conductive layer provided in some embodiments of the present application.

[0038] FIG5 is a second schematic diagram of the distribution structure of the exhaust units on the conductive layer provided in some embodiments of the present application.

[0039] FIG6 is a third schematic diagram of the distribution structure of the exhaust units on the conductive layer provided in some embodiments of the present application.

[0040] FIG7 is a fourth schematic diagram of the distribution structure of the exhaust units on the conductive layer provided in some embodiments of the present application.

[0041] FIG8 is a schematic structural diagram of the conductive layer punching process provided in some embodiments of the present application.

[0042] FIG9 is a fifth schematic diagram of the distribution structure of the exhaust units on the conductive layer provided in some embodiments of the present application.

[0043] FIG10 is a cross-sectional view of a conductive layer structure with an inclined exhaust unit provided in some embodiments of the present application.

[0044] 100. Composite current collector; 10. Substrate; 20. Adhesive layer; 30. Conductive layer; 31. Exhaust unit; 32. Unit row; T, first direction; P, second direction; H, thickness direction; 200. Laser drilling device; 300. Roller; 400. Vehicle; 410. Secondary battery; 420. Controller; 430. Motor; 411. Housing; 412. End cap; 413. Electrode assembly; 414. Electrode terminal. DETAILED DESCRIPTION

[0045] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0046] In the description of this application, it should be understood that if the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. appear, the orientation or position relationship indicated by these terms is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0047] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include at least one of such features. In the description of this application, if the term "plurality" appears, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0048] In this application, unless otherwise specified or limited, the terms "mounted," "connected," "connected," "fixed," etc., should be interpreted broadly. For example, these terms may refer to fixed connections, removable connections, or integration; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; and internal communication between two components or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of these terms in this application based on the specific circumstances.

[0049] In this application, unless otherwise expressly specified or limited, when a first feature is described as being "above" or "below" a second feature, or similarly, this may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is described as being "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is described as being "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0050] It should be noted that if an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. If an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element. If any, the terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this application are for illustrative purposes only and do not represent the only embodiment.

[0051] Currently, market developments indicate that power batteries are becoming increasingly widely used. They are not only used in energy storage systems such as hydropower, thermal, wind, and solar power plants, but are also widely used in electric vehicles like electric bicycles, electric motorcycles, and electric vehicles, as well as in military equipment and aerospace. As power battery applications continue to expand, market demand is also growing.

[0052] During battery production, active materials are typically coated onto current collectors to create the desired positive and negative electrodes. Current collectors can be conventional metal foils, such as aluminum or copper foil, or composite current collectors. Composite current collectors consist of a conductive layer attached to a substrate, for example, by adhesive bonding.

[0053] Since there will be more or less residual gas in the glue, when the conductive layer is bonded and pressed onto the substrate, it is difficult for the gas to escape from the glue, resulting in incomplete adhesion between the substrate and the conductive layer. The bonding force between the two is poor, resulting in the risk of sporadic peeling of the conductive layer.

[0054] Based on this, in order to effectively solve the problem of the risk of the conductive layer on the surface of the composite current collector falling off due to the glue bonding, the present application provides a composite current collector, in which an exhaust unit is set on the conductive layer, so that during the preparation process, the conductive layer is bonded to the substrate and the conductive layer is pressed. Since there is an exhaust unit on the conductive layer, the gas remaining in the glue during the pressing process will be discharged from the exhaust unit, so that the conductive layer and the substrate are fully adhered, the bonding force between the conductive layer and the substrate is improved, and the probability of the conductive layer falling off is effectively reduced. At the same time, during the pressing process, part of the glue will penetrate into the exhaust unit, enhance the adhesion strength, and make the conductive layer and the substrate tightly bonded, thereby improving the stability of the composite current collector structure.

[0055] The secondary battery disclosed in the embodiments of the present application can be used, but is not limited to, in electrical devices such as vehicles, ships, or aircraft. A power supply system comprising the secondary battery disclosed in the present application can be used to form the electrical device.

[0056] In a battery system, there can be multiple secondary batteries, and the multiple secondary batteries can be connected in series, in parallel, or in a mixed connection. Mixed connection means that multiple secondary batteries are connected in series and in parallel. Multiple secondary batteries can be directly connected in series, in parallel, or in a mixed connection, and then the whole formed by the multiple secondary batteries is accommodated in a box; of course, the battery can also be a battery module formed by first connecting multiple secondary batteries in series, in parallel, or in a mixed connection, and then the multiple battery modules are connected in series, in parallel, or in a mixed connection to form a whole, and accommodated in a box. The battery can also include other structures. For example, the battery can also include a busbar component for realizing electrical connection between multiple secondary batteries. Among them, the secondary battery can be cylindrical, flat, rectangular, or other shapes.

[0057] The present invention provides an electric device that uses a battery as a power source. The electric device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, a battery-powered vehicle, an electric car, a ship, a spacecraft, etc. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc. The spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0058] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device according to an embodiment of the present application.

[0059] Please refer to Figure 1, which is a structural schematic diagram of a vehicle 400 provided in some embodiments of the present application. The vehicle 400 can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc. A secondary battery 410 is provided inside the vehicle 400, and the secondary battery 410 can be provided at the bottom, head or tail of the vehicle 400. The secondary battery 410 can be used to power the vehicle 400. For example, the secondary battery 410 can serve as an operating power source for the vehicle 400. The vehicle 400 may also include a controller 420 and a motor 430. The controller 420 is used to control the secondary battery 410 to power the motor 430, for example, for starting, navigating and driving the vehicle 400.

[0060] Please refer to Figure 2, which is a schematic diagram of the exploded structure of a secondary battery 410 provided in some embodiments of the present application. Secondary battery 410 is the smallest unit of a battery. As shown in Figure 2, secondary battery 410 includes an end cap 412, a housing 411, an electrode assembly 413, and other functional components.

[0061] The end cap 412 is a component that fits over the opening of the housing 411 to isolate the internal environment of the secondary battery 410 from the external environment. The shape of the end cap 412 can be adapted to the shape of the housing 411 to fit the housing 411. In some embodiments, the end cap 412 can be made of a material with a certain degree of hardness and strength (such as an aluminum alloy). This prevents the end cap 412 from deforming when subjected to compression or collision, thereby providing the secondary battery 410 with greater structural strength and improved safety. Functional components such as electrode terminals 414 can be provided on the end cap 412. The electrode terminals 414 can be used to electrically connect to the electrode assembly 413 for inputting or outputting electrical energy from the secondary battery 410. In some embodiments, the end cap 412 can also be provided with a pressure relief mechanism for relieving internal pressure when the internal pressure or temperature of the secondary battery 410 reaches a threshold. The end cap 412 can be made of a variety of materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and this is not particularly limited in the present embodiment. In some embodiments, an insulating member may be provided inside the end cap 412 to isolate the electrical connection components in the housing 411 from the end cap 412 to reduce the risk of short circuit.

[0062] The shell 411 is a component used to cooperate with the end cap 412 to form the internal environment of the secondary battery 410, wherein the formed internal environment can be used to accommodate the electrode assembly 413, electrolyte and other components. The shell 411 and the end cap 412 can be independent components. An opening can be set on the shell 411, and the internal environment of the secondary battery 410 is formed by covering the opening with the end cap 412. Without limitation, the end cap 412 and the shell 411 can also be integrated. Specifically, the end cap 412 and the shell 411 can form a common connection surface before other components are inserted into the shell. When the interior of the shell 411 needs to be encapsulated, the end cap 412 is then covered with the shell 411. The shell 411 can be of various shapes and sizes, such as a rectangular parallelepiped, a cylindrical shape, a hexagonal prism, etc. Specifically, the shape of the shell 411 can be determined according to the specific shape and size of the electrode assembly 413. The shell 411 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., and the embodiment of the present application does not impose any special restrictions on this.

[0063] The electrode assembly 413 is a component in the secondary battery 410 where electrochemical reactions occur. One or more electrode assemblies 413 may be contained in the housing 411. The electrode assembly 413 is mainly formed by winding or stacking a positive electrode sheet and a negative electrode sheet, and a separator is usually provided between the positive electrode sheet and the negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active materials constitute the main body of the electrode assembly 413, and the parts of the positive electrode sheet and the negative electrode sheet without active materials each constitute a tab. The positive electrode tab and the negative electrode tab may be located together at one end of the main body or respectively at both ends of the main body. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs are connected to the electrode terminals 414 to form a current loop.

[0064] According to some embodiments of the present application, referring to FIG. 3 , a composite current collector 100 is provided. The composite current collector 100 includes a substrate 10 and a conductive layer 30 . The conductive layer 30 is bonded to at least one side of the substrate 10 . A venting unit 31 is provided on the conductive layer 30 , with at least a portion of the venting unit 31 extending through the conductive layer 30 in the thickness direction H of the composite current collector 100 .

[0065] Substrate 10 refers to the supporting structure of composite current collector 100, and its material can be selected from at least one of an organic polymer insulating material, an inorganic insulating material, and a composite material. The organic polymer insulating material is preferably at least one of polyamide, polyterephthalate, polyimide, polyethylene, polypropylene, polystyrene, polyvinyl chloride, acrylonitrile-butadiene-styrene copolymer, polybutylene terephthalate, poly(p-phenylene terephthalamide), polypropylene, polyoxymethylene, epoxy resin, phenolic resin, polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, and polycarbonate. The inorganic insulating material is preferably at least one of aluminum oxide, silicon carbide, and silicon dioxide. The composite material is preferably at least one of epoxy resin glass fiber reinforced composite material and polyester resin glass fiber reinforced composite material.

[0066] The conductive layer 30 is a conductive structure that collects the current generated by the active material layer for external output. In the electrode, the side of the conductive layer 30 facing away from the substrate 10 is used to coat the active material. Examples include lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, and ternary materials. Alternatively, graphite or silicon oxide may be used.

[0067] For example, the conductive layer 30 can be copper foil or aluminum foil. Furthermore, the conductive layer 30 can be bonded to one side of the substrate 10 or to both opposite sides of the substrate 10. It is understood that the conductive layer 30 being bonded to at least one side of the substrate 10 indicates that there is an adhesive layer 20 between the conductive layer 30 and the substrate 10, and that the conductive layer 30 is bonded to the substrate 10 via the adhesive layer 20.

[0068] It should also be noted that the exhaust unit 31 is a structure that penetrates the conductive layer 30. When the conductive layer 30 is bonded and pressed onto the substrate 10, residual gas in the glue can be discharged through the exhaust unit 31. At the same time, some glue can also penetrate the exhaust unit 31, strengthening the bonding force between the conductive layer 30 and the substrate 10. The direction of the exhaust unit 31 penetrating the conductive layer 30 can be consistent with the thickness direction H of the composite current collector 100, or it can intersect with the thickness direction H of the composite current collector 100.

[0069] The exhaust units 31 can be designed as either hole-like or groove-like structures. At least some exhaust units 31 penetrate the conductive layer 30 along the thickness direction H, indicating that some exhaust units 31 may not penetrate the conductive layer 30. Exhaust units 31 that do not penetrate the conductive layer 30 can be positioned on the side of the conductive layer 30 facing the substrate 10, forming a groove-like structure to facilitate gas flow and discharge along this groove-like structure.

[0070] In addition, the exhaust unit 31 is opened on the conductive layer 30, and one end thereof does not extend into the glue or onto the substrate 10. That is, one end of the exhaust unit 31 is located on the side of the conductive layer 30 facing away from the substrate 10, and the other end is located on the side of the conductive layer 30 facing the substrate 10.

[0071] The shape of the exhaust unit 31 can be designed in many ways, for example, it can be designed into regular shapes such as, but not limited to, circle, ellipse, square, pentagon, etc. Of course, it can also be designed into irregular shapes.

[0072] With this design, the gas remaining in the glue during the lamination process is discharged from the exhaust unit 31, ensuring sufficient adhesion between the conductive layer 30 and the substrate 10, improving the bonding strength between the conductive layer 30 and the substrate 10, and effectively reducing the risk of the conductive layer 30 falling off. At the same time, during the lamination process, some glue will penetrate into the exhaust unit 31, strengthening the adhesion strength and ensuring a tight bond between the conductive layer 30 and the substrate 10, thereby improving the structural stability of the composite current collector 100.

[0073] According to some embodiments of the present application, referring to FIG. 4 , the exhaust unit 31 includes a plurality of exhaust units 31 , and the exhaust units 31 are distributed at intervals on the conductive layer 30 .

[0074] The exhaust units 31 are spaced apart on the conductive layer 30 to increase the exhaust range on the conductive layer 30 and facilitate uniform exhaust. The exhaust units 31 can be distributed on the conductive layer 30 in various ways, such as: spaced apart in a matrix; spaced apart in multiple circular patterns; or randomly and closely packed.

[0075] In this way, sealing multiple exhaust units 31 on the conductive layer 30 can increase the exhaust range, effectively reduce the residual gas between the conductive layer 30 and the substrate 10, and improve the bonding strength between the conductive layer 30 and the substrate 10; in addition, the multiple exhaust units 31 can also serve as penetration points for glue, further improving the bonding strength between the conductive layer 30 and the substrate 10.

[0076] According to some embodiments of the present application, the distribution density of the exhaust unit 31 on the conductive layer 30 is recorded as n, where 1 unit / dm2. 2 )≤n≤100 pieces / dm 2 .

[0077] The distribution density of the exhaust unit 31 refers to the number of exhaust units 31 contained in a unit area. For example, the distribution density of the exhaust unit 31 can be 1 / dm 2 ~100 pieces / dm 2 For example, the distribution density of the exhaust unit 31 can be but not limited to 1 / dm 2 , 10 / dm 2 , 20 pieces / dm2 , 30 pieces / dm 2 , 40 pieces / dm 2 , 50 pieces / dm 2 , 60 pieces / dm 2 , 70 pieces / dm 2 , 80 pieces / dm 2 , 90 pieces / dm 2 , 100 pieces / dm 2 wait.

[0078] It should be noted that there are various methods for obtaining the distribution density of the exhaust cells 31. For example, the total number of exhaust cells 31 on the conductive layer 30 and the area of ​​one side of the conductive layer 30 can be obtained, and then the total number can be divided by the area of ​​the side of the conductive layer 30. Of course, a method of averaging values ​​across multiple regions can also be used. For example, multiple regions of the same size can be randomly selected on the conductive layer 30, and the number of exhaust cells 31 in each region can be calculated and averaged. The ratio of the average value to the area of ​​the selected region can be used as the distribution density of the exhaust cells 31.

[0079] With this design, the distribution density of the exhaust unit 31 is controlled at 1 / dm 2 ~100 pieces / dm 2 The exhaust effect and the structural strength of the conductive layer 30 can be effectively taken into account.

[0080] According to some embodiments of the present application, the distribution density n also satisfies the following conditions: 4 pieces / dm 2 ≤n≤25 pieces / dm 2 .

[0081] The distribution density can be further controlled to 4 / dm 2 ~25 pieces / dm 2 , for example, the distribution density can be but not limited to 4 / dm 2 , 6 / dm 2 , 8 / dm 2 , 10 / dm 2 , 12 pieces / dm 2 , 14 / dm 2 , 16 / dm 2 , 18 / dm 2 , 20 pieces / dm 2 , 22 pieces / dm 2 , 24 / dm 2 , 25 pieces / dm 2 wait.

[0082] In this way, the distribution density is further limited to 4 / dm 2 ~25 pieces / dm 2While ensuring effective exhaust, the number of holes or grooves on the conductive layer 30 is minimized, so that the conductive layer 30 has a certain structural strength and the overall structural stability of the composite current collector 100 is improved.

[0083] According to some embodiments of the present application, referring to FIG. 5 , the exhaust units 31 are spaced apart in a first direction T to form a plurality of unit rows 32 , and the exhaust units 31 in each unit row 32 are spaced apart along a second direction P. In at least two adjacent unit rows 32 , the exhaust units 31 in one unit row 32 are staggered with the exhaust units 31 in the other unit row 32 in the first direction T. The first direction T intersects with the second direction P, and the plane formed by them intersects with the thickness direction H.

[0084] A unit row 32 is a structure formed by a plurality of exhaust units 31 arranged in the second direction P. The number of exhaust units 31 in each unit row 32 can be the same or different. Furthermore, within a unit row 32, the exhaust units 31 arranged in the second direction P can be arranged in a straight line or staggered in the second direction P, i.e., not arranged in a straight line.

[0085] In the first direction T, the exhaust units 31 between at least two adjacent unit rows 32 are offset from each other. This means that, among the two adjacent unit rows 32, the exhaust units 31 of one unit row 32 and the exhaust units 31 of the other unit row 32 are not on the same straight line along the first direction T. For example, among two adjacent unit rows 32, the exhaust unit 31 of one unit row 32 may be located between two exhaust units 31 of the other unit row 32.

[0086] Specifically, in some embodiments, the exhaust units 31 between any two adjacent unit rows 32 are staggered in the first direction T.

[0087] To achieve staggered punching, various punching methods are possible. For example, after punching the first row of exhaust cells 31, the second row of exhaust cells 31 is completely staggered with the first row of exhaust cells 31. Next, the third row of exhaust cells 31 can be aligned with the first row of exhaust cells 31 in the first direction T. The fourth and second rows of exhaust cells 31 are then aligned, and this cycle repeats. For details, please refer to Figure 5. At this point, the distance Z1 between the third row and the first row can be twice the distance Z0 between the first and second rows, and the distance X0 between two adjacent exhaust cells 31 in the first row is twice the distance X1 between two adjacent exhaust cells 31 in the first and second rows in the second direction P.

[0088] Alternatively, after the first row of exhaust units 31 is installed, the second and third rows are sequentially staggered. Next, the fourth, fifth, and sixth rows of exhaust units 31 are arranged according to the distribution of the first, second, and third rows, respectively, and this cycle repeats. For details, see Figure 6. In this case, the distance Z2 between the fourth row and the first row can be three times the distance Z0 between the first and second rows, and the distance X0 between two adjacent exhaust units 31 in the first row is three times the distance X1 between two adjacent exhaust units 31 in the first and second rows in the second direction P.

[0089] Alternatively, after the first row of exhaust cells 31 is installed, the second, third, and fourth rows are sequentially staggered. Next, the fifth, sixth, seventh, and eighth rows of exhaust cells 31 are arranged according to the distribution of the first, second, third, and fourth rows, respectively, and this cycle repeats. For details, please refer to FIG7 . In this case, the distance Z3 between the fifth row and the first row can be four times the distance Z0 between the first and second rows, and the distance X0 between two adjacent exhaust cells 31 in the first row can be four times the distance X1 between two adjacent exhaust cells 31 in the first and second rows in the second direction P.

[0090] Of course, the punching methods of this embodiment are not limited to the above-mentioned methods. Any method can be used as long as the exhaust units 31 in at least two adjacent unit rows 32 are staggered. Furthermore, during the above preparation process, a laser punching device 200 can be used. As shown in FIG8 , while the laser punching device 200 is punching, the roller 300 stops conveying the conductive layer 30 .

[0091] The first direction T and the second direction P intersect with each other and intersect with the thickness direction H. In some embodiments, the first direction T, the second direction P, and the thickness direction H are perpendicular to each other. Furthermore, the first direction T can be the length direction of the conductive layer 30 or the width direction of the conductive layer 30. When the first direction T is the width direction, the perforation method can be referred to in FIG9 .

[0092] With such a design, the exhaust units 31 in at least two adjacent groups of unit rows 32 are staggered in the first direction T, so that the force on the conductive layer 30 in the first direction T will not be concentrated on the exhaust units 31 in each group of unit rows 32 at the same time, thereby having a better effect on alleviating the tensile strength and tensile elongation of the conductive layer 30; at the same time, due to the staggered distribution, the exhaust units 31 between two adjacent groups of unit rows 32 can be arranged closer together, so that the exhaust range is larger and the exhaust effect is more uniform.

[0093] According to some embodiments of the present application, referring to FIG. 4 , in each unit row 32 , the distance between two adjacent exhaust units 31 is denoted as X, where 10 mm ≤ X ≤ 100 mm.

[0094] The distance X between two adjacent exhaust units 31 may be between 10 mm and 100 mm. For example, the distance X may be, but is not limited to, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc.

[0095] With this design, the distance between two adjacent exhaust units 31 is controlled between 10 mm and 100 mm. By rationally controlling the distance between the exhaust units 31, the conductive layer 30 maintains a certain structural strength in the second direction P; at the same time, the gas is evenly discharged in the second direction P during pressing.

[0096] According to some embodiments of the present application, the spacing X further satisfies the condition: 20 mm ≤ X ≤ 50 mm.

[0097] The distance X between two adjacent exhaust units 31 may be between 20 mm and 50 mm. For example, the distance X may be, but is not limited to, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc.

[0098] With this design, the distance between two adjacent exhaust units 31 is further controlled to be between 20 mm and 50 mm, so that the structural design of the conductive layer 30 can more effectively take into account both structural strength and gas exhaust effect.

[0099] According to some embodiments of the present application, please refer to Figure 4. In two adjacent groups of unit rows 32, the distance between the exhaust unit 31 in one group of unit rows 32 and the corresponding exhaust unit 31 in the other group of unit rows 32 in the first direction T is recorded as Z, where 0mm≤Z≤100mm.

[0100] The distance Z between the two exhaust units 31 can be between 0 mm and 100 mm. For example, the distance X can be but not limited to 0 mm, 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, 100 mm, etc.

[0101] Among them, in the first direction T, the exhaust units 31 in the two groups of unit rows 32 can be staggered. Therefore, when Z is 0 mm, there is a certain distance between the two exhaust units 31 in the second direction P, so that the two exhaust units 31 will not overlap during punching.

[0102] With this design, the spacing between two adjacent exhaust units 31 in the first direction T is controlled between 0 mm and 100 mm. In this way, the spacing between the exhaust units 31 is reasonably controlled so that the conductive layer 30 maintains a certain structural strength in the first direction T; at the same time, the gas is evenly discharged in the first direction T during pressing.

[0103] According to some embodiments of the present application, referring to FIG. 4 , the spacing Z further satisfies the condition: 20 mm ≤ Z ≤ 50 mm.

[0104] The distance Z between two adjacent exhaust units 31 can be between 20 mm and 50 mm. For example, the distance Z can be, but is not limited to, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc.

[0105] With this design, the distance between two adjacent exhaust units 31 in the first direction T is further controlled to be between 20 mm and 50 mm, so that the structural design of the conductive layer 30 can more effectively balance structural strength and gas exhaust effect.

[0106] According to some embodiments of the present application, the first direction T is configured as the length direction of the conductive layer 30 , and the second direction P is configured as the width direction of the conductive layer 30 .

[0107] The length direction of the conductive layer 30 can also be understood as the direction in which the conductive layer 30 is conveyed. For example, before being cut to the desired size, the conductive layer 30 is continuously transported forward by the conveyor rollers. In this case, the conveyor direction can be considered the length direction of the conductive layer 30. Of course, the conveyor direction of the conductive layer 30 can also be the direction in which the conductive layer 30 is continuously conveyed forward during the punching process.

[0108] With this design, the first direction is controlled as the length direction, which facilitates the processing of exhaust units in rows in the length direction; at the same time, it is also beneficial to dislocation in the length direction, alleviating the tensile strength and tensile elongation of the conductive layer in the length direction.

[0109] According to some embodiments of the present application, referring to FIG. 10 , the penetration direction of the exhaust unit 31 is tilted relative to the thickness direction H.

[0110] The direction of penetration of the exhaust unit 31 is inclined relative to the thickness direction H, indicating that the exhaust unit 31 is formed to penetrate the conductive layer 30 at a certain angle, such as by drilling. It should be noted that when there are multiple exhaust units 31, some or all of the exhaust units 31 can be designed as inclined holes.

[0111] In this way, the exhaust unit 31 is designed to be an inclined structure, such as an inclined hole, etc., which can extend the extension length of the exhaust unit 31 on the conductive layer 30, effectively reducing the glue from penetrating from the exhaust unit 31 to the outer surface of the conductive layer 30; at the same time, the glue that penetrates into the inclined exhaust unit 31 will be subjected to the upward force of the inner wall of the exhaust unit 31, which can effectively reduce the probability of falling off, make the bonding force stronger, and help to improve the overall structural strength of the composite current collector 100.

[0112] According to some embodiments of the present application, referring to FIG. 10 , an acute angle is formed between the penetration direction of the exhaust unit 31 and the thickness direction H, and is denoted as θ, where 30°≤θ≤80°.

[0113] The acute angle θ may be between 30° and 80°. For example, the acute angle θ may be, but is not limited to, 30°, 40°, 45°, 50°, 60°, 70°, 80°, and the like.

[0114] With this design, the acute angle θ is controlled between 30° and 80°, so that the exhaust unit 31 is better tilted on the conductive layer 30 , thereby better reducing the glue from penetrating from the exhaust unit 31 to the outer surface of the conductive layer 30 .

[0115] According to some embodiments of the present application, the acute angle θ further satisfies the condition: 50°≤θ≤70°.

[0116] The acute angle θ may be between 50° and 70°. For example, the acute angle θ may be, but is not limited to, 50°, 55°, 60°, 65°, 70°, and the like.

[0117] With this design, the acute angle θ is controlled between 50° and 70°, so that the exhaust unit 31 can maintain a certain tilt on the conductive layer 30; at the same time, the processing difficulty of the exhaust unit 31 is reduced, effectively taking into account the anti-overflow glue effect and processing convenience.

[0118] According to some embodiments of the present application, referring to FIG. 4 , the exhaust unit 31 is constructed as a circular hole, and the diameter of the exhaust unit 31 is denoted as D1 , where 1 nanometer (nm) ≤ D1 ≤ 5000 nm.

[0119] The diameter of the exhaust unit 31 should not be too large, as it will easily cause glue leakage and weaken the structural strength of the conductive layer 30; nor should it be too small, as it will not only increase the processing difficulty of the exhaust unit 31 but also have a poor exhaust effect.

[0120] To this end, the diameter of the exhaust unit 31 can be between 1 nm and 5000 nm. For example, the diameter of the exhaust unit 31 can be 1 nm, 10 nm, 100 nm, 1000 nm, 2000 nm, 3000 nm, 4000 nm, 5000 nm, etc.

[0121] With this design, the diameter of the exhaust unit 31 is controlled between 1 nm and 5000 nm, making it less likely for the composite current collector 100 to escape. It is also beneficial for exhaust between the conductive layer 30 and the substrate 10, thereby improving the bonding strength between the two.

[0122] According to some embodiments of the present application, the diameter D1 further satisfies the condition: 50 nm ≤ D1 ≤ 300 nm.

[0123] The diameter of the exhaust unit 31 may also be between 50 nm and 300 nm. For example, the diameter of the exhaust unit 31 may be 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, etc.

[0124] With this design, the diameter of the exhaust unit 31 is controlled between 50 nm and 300 nm, so that the design of the exhaust unit 31 can more effectively take into account both the anti-escape effect and the exhaust effect.

[0125] According to some embodiments of the present application, an adhesive layer 20 is disposed between the conductive layer 30 and the substrate 10 , and one end of the exhaust unit 31 extends to a side of the conductive layer 30 facing the adhesive layer 20 .

[0126] The adhesive layer 20 is a layer bonded between the conductive layer 30 and the substrate 10. During the manufacturing process, some of the adhesive layer 20 may penetrate into the venting unit 31. During the manufacturing process, the venting unit 31 penetrates the conductive layer 30 but does not extend into the adhesive layer 20 or onto the substrate 10.

[0127] There are many options for the material of the adhesive layer 20. For example, the material of the adhesive layer 20 may include one or more of a composition containing a multifunctional isocyanate and a polyester polyol compound, polyurethane, epoxy resin, polyacrylate, polyvinyl acetate, unsaturated polyester, phenolic resin, urea-formaldehyde resin, modified polyolefin resin, silicone resin, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, acrylic resin, polycarbonate, and polyamide. Preferably, the material of the adhesive layer 20 includes one or more of a composition containing a multifunctional isocyanate and a polyester polyol compound and polyurethane. The polyurethane includes one or more of thermoplastic polyurethane and reactive polyurethane.

[0128] In this way, the exhaust unit 31 is not extended to the adhesive layer 20 but is opened on the conductive layer 30 , which can reduce damage to the adhesive layer 20 and is conducive to improving the bonding strength between structures.

[0129] According to some embodiments of the present application, referring to FIG. 3 , the thickness of the adhesive layer 20 in the thickness direction H is denoted as D2 , wherein 200 nm ≤ D2 ≤ 1500 nm.

[0130] The thickness D2 may be between 200 nm and 1500 nm. For example, the thickness D2 may be, but is not limited to, 200 nm, 500 nm, 600 nm, 700 nm, 800 nm, 1000 nm, 1200 nm, 1500 nm, etc.

[0131] In this way, the thickness of the glue layer 20 is controlled between 200 nm and 1500 nm, which can ensure effective bonding while minimizing the amount of glue and controlling the thickness of the composite current collector 100 .

[0132] According to some embodiments of the present application, the thickness D2 further satisfies the condition: 300 nm ≤ D2 ≤ 700 nm.

[0133] The thickness D2 may be between 300 nm and 700 nm. For example, the thickness D2 may be, but is not limited to, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, and the like.

[0134] In this way, the thickness of the adhesive layer 20 is controlled between 300 nm and 700 nm, further effectively taking into account both the bonding strength and the investment cost of the composite current collector 100 .

[0135] According to some embodiments of the present application, referring to FIG. 3 , the thickness of the substrate 10 in the thickness direction H is denoted as D3 , wherein 2 micrometers (μm) ≤ D3 ≤ 10 μm.

[0136] The thickness D3 may be between 2 μm and 10 μm. For example, the thickness D3 may be, but is not limited to, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, etc.

[0137] In this way, the thickness of the substrate 10 is controlled between 2 μm and 10 μm. Under the premise of satisfying the structural strength, the overall thickness of the composite current collector 100 is reduced, thereby facilitating the improvement of the energy density of the battery.

[0138] According to some embodiments of the present application, the thickness D3 further satisfies the condition: 3 μm≤D3≤8 μm.

[0139] The thickness D3 may be between 3 μm and 8 μm. For example, the thickness D3 may be, but is not limited to, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, etc.

[0140] In this way, the thickness of the substrate 10 is controlled between 3 μm and 8 μm, so that the prepared composite current collector 100 can more effectively balance structural strength and thickness.

[0141] According to some embodiments of the present application, the present application provides a pole piece, which includes any one of the composite current collectors 100 described above.

[0142] According to some embodiments of the present application, the present application provides an electrode assembly, which includes the above electrode piece.

[0143] According to some embodiments of the present application, the present application provides a secondary battery, which includes the above electrode assembly.

[0144] According to some embodiments of the present application, the present application provides an electrical device, which includes the above secondary battery.

[0145] According to some embodiments of the present application, referring to FIG. 3 to FIG. 10 , the present application provides a composite current collector 100 comprising a substrate 10 and a conductive layer 30 bonded to both sides of the substrate 10 via an adhesive layer 20 , wherein the conductive layer 30 is provided with an exhaust unit 31 . During the preparation of the composite current collector 100 , by pressing the conductive layer 30 , not only is the conductive layer 30 and the substrate 10 tightly bonded, but the gas in the adhesive layer 20 is also facilitated to be discharged from the exhaust unit 31 , thereby ensuring that the prepared composite current collector 100 has a qualified bonding strength and solving the problem of sporadic shedding of the conductive layer 30 .

[0146] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0147] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present patent application shall be determined by the appended claims.

Claims

1. A composite current collector, the composite current collector comprising: a base material (10); a conductive layer (30) adhered to at least one side surface of the base material (10); wherein, an exhaust unit (31) is provided on the conductive layer (30), and at least a part of the exhaust unit (31) penetrates through the conductive layer (30) in the thickness direction (H) of the composite current collector.

2. The composite current collector according to claim 1, wherein, There are multiple exhaust units (31), and the exhaust units (31) are distributed at intervals on the conductive layer (30).

3. The composite current collector according to claim 2, wherein, The distribution density of the exhaust units (31) on the conductive layer (30) is denoted as n, where 1 piece / dm 2 ≤ n ≤ 100 pieces / dm 2 .

4. The composite current collector according to claim 3, wherein, The additional condition satisfied by the distribution density n is: 4 pieces / dm 2 ≤ n ≤ 25 pieces / dm 2 .

5. The composite current collector according to any one of claims 2-4, wherein, The exhaust units (31) form multiple groups of unit rows (32) at intervals in a first direction (T), and the exhaust units (31) in each group of the unit rows (32) are distributed at intervals in a second direction (P); wherein, in at least two adjacent groups of the unit rows (32), the exhaust units (31) in one group of the unit rows (32) are staggeredly distributed in the first direction (T) with the exhaust units (31) in the other group of the unit rows (32), the first direction (T) intersects with the second direction (P), and the formed plane intersects with the thickness direction (H).

6. The composite current collector according to claim 5, wherein, In each group of the unit rows (32), the distance between two adjacent exhaust units (31) is denoted as X, wherein, 10 mm ≤ X ≤ 100 mm.

7. The composite current collector according to claim 6, wherein, The condition that the distance X also satisfies is: 20 mm ≤ X ≤ 50 mm.

8. The composite current collector according to any one of claims 5-7, wherein, In two adjacent groups of the unit rows (32), the distance between the exhaust units (31) in one group of the unit rows (32) and the corresponding exhaust units (31) in the other group of the unit rows (32) in the first direction (T) is denoted as Z, wherein, 0 mm ≤ Z ≤ 100 mm.

9. The composite current collector according to claim 8, wherein, The condition that the distance Z also satisfies is: 20 mm ≤ Z ≤ 50 mm.

10. The composite current collector according to any one of claims 5-9, wherein, The first direction (T) is configured as the length direction of the conductive layer (30), and the second direction (P) is configured as the width direction of the conductive layer (30).

11. The composite current collector according to any one of claims 1-10, wherein, The penetration direction of the exhaust unit (31) is inclined relative to the thickness direction (H).

12. The composite current collector according to claim 11, wherein, There is an acute angle between the penetration direction of the exhaust unit (31) and the thickness direction (H), and it is denoted as θ, wherein, 30° ≤ θ ≤ 80°.

13. The composite current collector according to claim 12, wherein, The condition that the acute angle θ also satisfies is: 50° ≤ θ ≤ 70°.

14. The composite current collector according to any one of claims 1-13, wherein, The exhaust unit (31) is configured as a circular hole, and the diameter of the exhaust unit (31) is denoted as D1, wherein, 1 nm ≤ D1 ≤ 5000 nm.

15. The composite current collector according to claim 14, wherein, The condition that the diameter D1 also satisfies is: 50 nm ≤ D1 ≤ 300 nm.

16. The composite current collector according to any one of claims 1-15, wherein, There is an adhesive layer (20) between the conductive layer (30) and the base material (10), and one end of the exhaust unit (31) extends to the side surface of the conductive layer (30) facing the adhesive layer (20).

17. The composite current collector according to claim 16, wherein, The thickness of the adhesive layer (20) in the thickness direction (H) is denoted as D2, wherein, 200 nm ≤ D2 ≤ 1500 nm.

18. The composite current collector according to claim 17, wherein, The condition that the thickness D2 also satisfies is: 300 nm ≤ D2 ≤ 700 nm.

19. The composite current collector according to any one of claims 1-18, wherein, The thickness of the base material (10) in the thickness direction (H) is denoted as D3, wherein, 2 μm ≤ D3 ≤ 10 μm.

20. The composite current collector according to claim 19, wherein, The condition that the thickness D3 also satisfies is: 3 μm ≤ D3 ≤ 8 μm.

21. A current collector, the current collector comprising the composite current collector according to any one of claims 1-20.

22. An electrode assembly, the electrode assembly comprising the current collector according to claim 21.

23. A secondary battery, the secondary battery comprising the electrode assembly according to claim 22.

24. An electrical device, the electrical device comprising the secondary battery according to claim 23.

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