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

Abstract

The utility model relates to a composite current collector, a pole piece, an electrode assembly, a secondary battery and an electric device, an exhaust unit penetrating through a conductive layer is arranged on the conductive layer, so that in the preparation process, the conductive layer is bonded on a base material, and the conductive layer is pressed. Due to the fact that the conducting layer is provided with the exhaust unit, residual gas in glue in the pressing process can be exhausted from the exhaust unit, the conducting layer and the base material are fully adhered, the binding force between the conducting layer and the base material is improved, and the probability that the conducting layer has the falling risk is effectively reduced. Meanwhile, in the pressing process, part of glue can permeate into the exhaust units, the adhesion strength is enhanced, the conducting layer and the base material are tightly combined, and therefore the stability of the composite current collector structure is improved.

Description

Technical Field

[0001] 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

[0002] 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 increase in the requirements for battery reliability, composite current collectors have also been proposed. Composite current collectors refer to the structure obtained by combining the conductive layer and the polymer layer. If the conductive layer and the polymer layer are bonded by glue, there is a risk of the conductive layer on its surface falling off.

[0003] The above statements are only used to provide background information related to the present application and do not necessarily constitute prior art. Utility Model Content

[0004] 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.

[0005] 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.

[0006] The above-mentioned composite current collector is provided with an exhaust 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 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, make the conductive layer and the substrate tightly bonded, thereby improving the stability of the composite current collector structure.

[0007] In some embodiments, the exhaust unit includes a plurality of exhaust units, which are spaced apart on the conductive layer. Thus, sealing a plurality of exhaust units on the conductive layer can increase the exhaust range, effectively reduce the residual gas between the conductive layer and the substrate, and improve the bonding strength between the conductive layer and the substrate; in addition, the plurality of exhaust units can also serve as penetration points for glue, further improving the bonding strength between the conductive layer and the substrate.

[0008] In some embodiments, the distribution density of the exhaust units on the conductive layer is denoted as n, where 1 unit / dm 2≤n≤100pcs / dm 2 This design controls the distribution density of the exhaust unit to 1 unit / dm 2 ~100 pieces / dm 2 The exhaust effect and the structural strength of the conductive layer can be effectively taken into account.

[0009] In some embodiments, the distribution density n also satisfies the following conditions: 4 pieces / dm 2 ≤n≤25pcs / 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.

[0010] In some embodiments, the exhaust units are spaced apart in the first direction to form multiple groups of unit rows, and the exhaust units in each group of unit rows are spaced apart along the second direction; wherein, in at least one adjacent group of unit rows, the exhaust units in one group of unit rows are staggeredly distributed with the exhaust units in the other group of unit rows in the first direction, the first direction intersects with the second direction, and the plane formed intersects with the thickness direction. In this design, the exhaust units in at least one adjacent group of unit rows are staggeredly distributed in the first direction, so that the force on the conductive layer in the first direction will not be concentrated on the exhaust units in each group of unit rows at the same time, so that the tensile property strength and tensile elongation of the conductive layer are better alleviated; at the same time, due to the staggered distribution, the exhaust units between the two adjacent groups of unit rows can be arranged closer, so that the exhaust range is larger and the exhaust effect is more uniform.

[0011] In some embodiments, in each group of unit rows, the distance between two adjacent exhaust units is recorded as X, where 10mm≤X≤100mm. In this design, the distance between two adjacent exhaust units is controlled between 10mm and 100mm. In this way, the distance between the exhaust units is reasonably controlled so that the conductive layer maintains a certain structural strength in the second direction; at the same time, the gas is evenly discharged in the second direction during pressing.

[0012] In some embodiments, the spacing X also satisfies the condition: 20 mm ≤ X ≤ 50 mm. With such a 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 take into account both structural strength and gas exhaust effect.

[0013] In some embodiments, in two adjacent groups of unit rows, the spacing between the exhaust unit in one group of unit rows and the corresponding exhaust unit in the other group of unit rows in the first direction is recorded as Z, where 0mm≤Z≤100mm. In this design, the spacing between two adjacent exhaust units in the first direction is controlled between 0mm and 100mm, so that the spacing between the exhaust units is reasonably controlled, so that the conductive layer maintains a certain structural strength in the first direction; at the same time, the gas is evenly discharged in the first direction during pressing.

[0014] In some embodiments, the spacing Z also satisfies the condition: 20 mm ≤ Z ≤ 50 mm. With such a 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 take into account both structural strength and gas exhaust effect.

[0015] 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. With this design, the first direction is controlled as the length direction, which is convenient for processing the 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.

[0016] In some embodiments, the penetration direction of the exhaust unit is inclined relative to the thickness direction. In this way, the exhaust unit is designed as an inclined structure, which can extend the extension length of the exhaust unit on the conductive layer and effectively reduce the glue from the exhaust unit to the outer surface of the conductive layer; at the same time, the glue that penetrates into the inclined exhaust unit will be subjected to the upward force of the inner wall of the exhaust unit, which can effectively reduce the probability of falling off, making the bonding force stronger, which is conducive to improving the overall structural strength of the composite current collector.

[0017] In some embodiments, there is an acute angle between the penetration direction and the thickness direction of the exhaust unit, which is recorded as θ, where 30°≤θ≤80°. In this design, the acute angle θ is controlled between 30° and 80°, so that the exhaust unit is better tilted on the conductive layer, thereby better reducing the glue from the exhaust unit to the outer surface of the conductive layer.

[0018] In some embodiments, the acute angle θ also satisfies the condition: 50°≤θ≤70°. With such a design, the acute angle θ is controlled between 50° and 70°, so that the exhaust unit can maintain a certain inclination on the conductive layer; and the processing difficulty of the exhaust unit can be reduced, effectively taking into account the anti-overflow effect and processing convenience.

[0019] In some embodiments, the exhaust unit is constructed as a circular hole, and the diameter of the exhaust unit is recorded as D1, where 1nm≤D1≤5000nm. With such a design, the diameter of the exhaust unit is controlled between 1nm and 5000nm, so that the gel run phenomenon is not easy to occur during the preparation of the composite current collector; and it is also conducive to the exhaust between the conductive layer and the substrate, thereby improving the bonding strength between the two.

[0020] In some embodiments, the diameter D1 also satisfies the condition: 50nm≤D1≤300nm. In this design, the diameter of the exhaust unit is controlled between 50nm and 300nm, so that the design of the exhaust unit can more effectively take into account both the anti-escape effect and the exhaust effect.

[0021] In some embodiments, there is an adhesive layer between the conductive layer and the substrate, and one end of the exhaust unit extends to a side of the conductive layer facing the adhesive layer. In this way, the exhaust unit is not extended to the adhesive layer, but is opened on the conductive layer, which can reduce damage to the adhesive layer and is conducive to improving the bonding strength between structures.

[0022] In some embodiments, the thickness of the glue layer in the thickness direction is recorded as D2, where 200nm≤D2≤1500nm. In this way, the thickness of the glue layer is controlled between 200nm and 1500nm, while ensuring effective bonding, minimizing the input of glue and controlling the thickness of the composite current collector.

[0023] In some embodiments, the thickness D2 also satisfies the condition: 300 nm ≤ D2 ≤ 700 nm. In this way, the thickness of the glue layer is controlled between 300 nm and 700 nm, further effectively taking into account the bonding strength and the investment cost of the composite current collector.

[0024] In some embodiments, the thickness of the substrate in the thickness direction is recorded as D3, where 2µm≤D3≤10µm. In this way, the thickness of the substrate is controlled between 2µm and 10µm, and the overall thickness of the composite current collector is reduced while satisfying the structural strength, thereby facilitating the improvement of the energy density of the battery.

[0025] In some embodiments, the thickness D3 also satisfies the condition: 3µm≤D3≤8µm. In this way, the thickness of the substrate is controlled between 3µm and 8µm, so that the prepared composite current collector can more effectively balance the structural strength and thickness.

[0026] In a second aspect, the present application provides a pole piece, which includes any of the composite current collectors described above.

[0027] In a third aspect, the present application provides an electrode assembly, which includes the above-mentioned electrode piece.

[0028] In a fourth aspect, the present application provides a secondary battery, and the secondary battery includes the above electrode assembly.

[0029] In a fifth aspect, the present application provides an electrical device, which includes the above secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a schematic diagram of the structure of a vehicle provided in some embodiments of the present application.

[0031] FIG. 2 is a schematic diagram of the exploded structure of a secondary battery provided in some embodiments of the present application.

[0032] FIG3 is a cross-sectional view of a composite current collector structure provided in some embodiments of the present application.

[0033] FIG. 4 is a schematic diagram 1 of the distribution structure of the exhaust units on the conductive layer provided in some embodiments of the present application.

[0034] FIG. 5 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.

[0035] FIG. 6 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.

[0036] FIG. 7 is a fourth schematic diagram of the distribution structure of the exhaust unit on the conductive layer provided in some embodiments of the present application.

[0037] FIG. 8 is a schematic diagram of the structure during the conductive layer punching process provided in some embodiments of the present application.

[0038] FIG. 9 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.

[0039] FIG. 10 is a cross-sectional view of a conductive layer structure with an inclined exhaust unit provided in some embodiments of the present application.

[0040] 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

[0041] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0042] In the description of the present 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 the present 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 the present application.

[0043] In addition, if the terms "first" or "second" appear, these terms are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, if the term "plurality" appears, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0044] In this application, unless otherwise clearly specified and limited, if the terms "installed", "connected", "connected", "fixed" and the like appear, these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integrated connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to the specific circumstances.

[0045] In the present application, unless otherwise clearly specified and limited, if there is a description that a first feature is "above" or "below" a second feature, etc., or similar descriptions appear, it 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 intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0046] 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 a central 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 a central element at the same time. 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 implementation method.

[0047] At present, from the perspective of market development, the application of power batteries is becoming more and more extensive. Power batteries are not only used in energy storage power systems such as hydropower, thermal power, wind power and solar power stations, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric cars, as well as military equipment and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also constantly expanding.

[0048] During the battery production process, active materials are usually coated on the current collector to obtain the required positive and negative electrodes. The current collector can be a conventional metal foil, such as aluminum foil, copper foil, etc.; it can also be a composite current collector. A composite current collector refers to a conductive layer set on a substrate, for example: the conductive layer is bonded to the substrate by glue.

[0049] 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 shedding of the conductive layer.

[0050] Based on this, in order to effectively solve the problem that the conductive layer on the surface of the composite current collector is at risk of falling off due to the bonding of glue in the composite current collector, the present application provides a composite current collector, and an exhaust unit that runs through the conductive layer 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.

[0051] The secondary battery disclosed in the embodiment of the present application can be used in, but not limited to, electrical devices such as vehicles, ships, or aircraft. A power supply system having the secondary battery disclosed in the present application and the like can be used to form the electrical device.

[0052] 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. A mixed connection means that the multiple secondary batteries are both 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 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 confluence component for realizing electrical connection between multiple secondary batteries. Among them, the secondary battery can be cylindrical, flat, rectangular, or in other shapes.

[0053] The embodiment of the present application provides an electric device using a battery as a power source, and the electric device may be, but is not limited to, a mobile phone, a tablet, a laptop, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, 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., and the spacecraft may include an airplane, a rocket, a space shuttle, and a spacecraft, etc.

[0054] For the convenience of description, the following embodiments are described by taking a vehicle as an example of an electrical device in an embodiment of the present application.

[0055] Please refer to Figure 1, which is a schematic diagram of the structure of a vehicle 400 provided in some embodiments of the present application. The vehicle 400 may be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle may 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 may be provided at the bottom, head or tail of the vehicle 400. The secondary battery 410 may be used to power the vehicle 400, for example, the secondary battery 410 may be used as an operating power source for the vehicle 400. The vehicle 400 may also include a controller 420 and a motor 430, and 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.

[0056] Please refer to FIG. 2, which is a schematic diagram of the exploded structure of a secondary battery 410 provided in some embodiments of the present application. The secondary battery 410 refers to the smallest unit of a battery. As shown in FIG. 2, the secondary battery 410 includes an end cap 412, a housing 411, an electrode assembly 413, and other functional components.

[0057] The end cap 412 refers to a component that covers the opening of the shell 411 to isolate the internal environment of the secondary battery 410 from the external environment. Without limitation, the shape of the end cap 412 can be adapted to the shape of the shell 411 to match the shell 411. Optionally, the end cap 412 can be made of a material with a certain hardness and strength (such as aluminum alloy), so that the end cap 412 is not easily deformed when it is squeezed and collided, so that the secondary battery 410 can have a higher structural strength and the safety performance can also be improved. Functional components such as electrode terminals 414 can be provided on the end cap 412. The electrode terminal 414 can be used to electrically connect to the electrode assembly 413 for outputting or inputting electrical energy of the secondary battery 410. In some embodiments, the end cap 412 can also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the secondary battery 410 reaches a threshold. The material of the end cap 412 can also be a variety of 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. 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. For example, the insulating member may be plastic, rubber, or the like.

[0058] 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, the electrolyte and other components. The shell 411 and the end cap 412 can be independent components, and 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 at the opening. 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 put into the shell, and when the interior of the shell 411 needs to be encapsulated, the end cap 412 covers 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 a variety of 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.

[0059] The electrode assembly 413 is a component in the secondary battery 410 where an electrochemical reaction occurs. One or more electrode assemblies 413 may be included 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 portion of the positive electrode sheet and the negative electrode sheet with active materials constitutes the main body of the electrode assembly 413, and the portion of the positive electrode sheet and the negative electrode sheet without active materials each constitutes 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 connect the electrode terminals 414 to form a current loop.

[0060] According to some embodiments of the present application, please refer to FIG. 3 , the present application provides a composite current collector 100, which includes: a substrate 10 and a conductive layer 30. The conductive layer 30 is bonded to at least one side of the substrate 10; wherein, a gas exhaust unit 31 is provided on the conductive layer 30, and at least part of the gas exhaust unit 31 penetrates the conductive layer 30 in the thickness direction H of the composite current collector 100.

[0061] The substrate 10 refers to a structure that supports the 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. Among them, 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.

[0062] The conductive layer 30 refers to a structure with a conductive function, which can collect the current generated by the active material layer for external output. At the same time, in the electrode, the side of the conductive layer 30 facing away from the substrate 10 is used to coat the active material, such as lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium iron phosphate, ternary materials, etc., and can also be coated with graphite, silicon oxide, etc.

[0063] Optionally, the conductive layer 30 may be a copper foil or an aluminum foil. Meanwhile, the conductive layer 30 may be bonded to one side of the substrate 10 or to both opposite sides of the substrate 10. It is known that the conductive layer 30 is bonded to at least one side of the substrate 10, which means that there is an adhesive layer 20 between the conductive layer 30 and the substrate 10, and the conductive layer 30 is bonded to the substrate 10 through the adhesive layer 20.

[0064] It should also be noted that the exhaust unit 31 refers to a structure that penetrates the conductive layer 30. When the conductive layer 30 is bonded and pressed onto the substrate 10, the gas remaining in the glue can be discharged through the exhaust unit 31. At the same time, part of the glue can also penetrate into the exhaust unit 31 to strengthen the bonding force between the conductive layer 30 and the substrate 10. The penetration direction of the exhaust unit 31 on the conductive layer 30 can be consistent with the thickness direction H of the composite current collector 100, or can intersect with the thickness direction H of the composite current collector 100.

[0065] The exhaust unit 31 may be designed as a hole-like structure or a groove-like structure. At least part of the exhaust unit 31 penetrates the conductive layer 30 along the thickness direction H, which means that part of the exhaust unit 31 may not penetrate the conductive layer 30. For the exhaust unit 31 that does not penetrate the conductive layer 30, it may be arranged on one side of the conductive layer 30 facing the substrate 10 to form a gully-like structure, so that the gas can flow and be discharged along the gully-like structure.

[0066] 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 surface of the conductive layer 30 facing away from the substrate 10, and the other end is located on the side surface of the conductive layer 30 facing the substrate 10.

[0067] Optionally, the shape of the exhaust unit 31 can be designed in a variety of ways, for example, it can be designed in a regular shape including but not limited to a circle, an ellipse, a square, a pentagon, etc. Of course, it can also be designed in an irregular shape.

[0068] With such a design, the gas remaining in the glue during the lamination process will be discharged from the exhaust unit 31, so that the conductive layer 30 and the substrate 10 are fully adhered, the bonding force between the conductive layer 30 and the substrate 10 is improved, and the probability of the conductive layer 30 falling off is effectively reduced. At the same time, during the lamination process, part of the glue will penetrate into the exhaust unit 31, enhancing the adhesion strength, so that the conductive layer 30 and the substrate 10 are tightly bonded, thereby improving the stability of the composite current collector 100 structure.

[0069] According to some embodiments of the present application, optionally, 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 .

[0070] The exhaust units 31 are distributed at intervals on the conductive layer 30, which can 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 a variety of ways, such as: distributed at intervals in a matrix manner; or distributed at intervals in multiple rings; or distributed in an irregular and dense manner.

[0071] 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 to further enhance the bonding strength between the conductive layer 30 and the substrate 10.

[0072] According to some embodiments of the present application, optionally, the distribution density of the exhaust unit 31 on the conductive layer 30 is recorded as n, where 1 unit / dm 2 ≤n≤100pcs / dm 2 .

[0073] 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 may be, but is not limited to, 1 / dm 2 , 10 / dm 2 , 20 pieces / dm 2 , 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.

[0074] It should be noted that there are many methods for obtaining the distribution density of the exhaust units 31, for example, obtaining the total number of exhaust units 31 on the conductive layer 30 and the area of ​​one side of the conductive layer 30; and then dividing the total number by the area of ​​one side of the conductive layer 30. Of course, a method of taking values ​​from multiple regions and finding an average value can also be adopted, such as randomly selecting multiple regions of the same specification on the conductive layer 30, and obtaining the number of exhaust units 31 in each region and finding the average value, and the ratio of the obtained average value to the area of ​​the selected region is the distribution density of the exhaust units 31, etc.

[0075] 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.

[0076] According to some embodiments of the present application, optionally, the distribution density n also satisfies the following conditions: 4 pieces / dm 2 ≤n≤25pcs / dm 2 .

[0077] 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 pieces / dm 2 , 18 / dm 2 , 20 pieces / dm 2 , 22 pieces / dm 2 , 24 / dm 2 , 25 pieces / dm 2 wait.

[0078] 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 30 is minimized, so that the conductive layer 30 has a certain structural strength, thereby improving the overall structural stability of the composite current collector 100.

[0079] According to some embodiments of the present application, optionally, referring to FIG. 5 , the exhaust units 31 are spaced apart in the 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 the second direction P. Among them, in at least two adjacent unit rows 32, the exhaust units 31 in one unit row 32 are staggeredly distributed 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 intersects with the thickness direction H.

[0080] The unit row 32 refers to a combined structure formed by a plurality of exhaust units 31 in the second direction P. The number of exhaust units 31 in each unit row 32 may be consistent or unequal. At the same time, in the unit row 32, the exhaust units 31 arranged along the second direction P may be distributed in the same straight line, or may be staggered in the second direction P, that is, not distributed along the same straight line.

[0081] In the first direction T, the exhaust units 31 between at least two adjacent unit rows 32 are offset from each other, which means that in two adjacent unit rows 32, the exhaust units 31 of one unit row 32 and the exhaust units 31 of another unit row 32 are not on the same straight line along the first direction T. For example, in two adjacent unit rows 32, the exhaust unit 31 of one unit row 32 may be located between two exhaust units 31 of another unit row 32, etc.

[0082] Specifically, in some embodiments, the exhaust units 31 between any two adjacent unit rows 32 are staggered in the first direction T.

[0083] In order to achieve staggered punching, there are many punching methods, for example: after punching the exhaust units 31 of the first row, the exhaust units 31 of the second row are completely staggered with the exhaust units 31 of the first row; then, the exhaust units 31 of the third row can be aligned with the exhaust units 31 of the first row in the first direction T; then, the exhaust units 31 of the fourth row and the second row are distributed in the same way, and so on. For details, please refer to Figure 5. At this time, the spacing Z1 between the third row and the first row can be twice the spacing Z0 between the first row and the second row, and the spacing X0 between two adjacent exhaust units 31 in the first row is twice the spacing X1 between two adjacent exhaust units 31 in the first row and the second row in the second direction P.

[0084] Alternatively, after the exhaust units 31 of the first row are installed, the second and third rows are arranged in a staggered manner; then, the exhaust units 31 of the fourth, fifth and sixth rows are arranged according to the distribution of the first, second and third rows, and the cycle repeats, for details, please refer to FIG. 6. At this time, the distance Z2 between the fourth row and the first row can be three times the distance Z0 between the first row and the second row, 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 row and the second row in the second direction P.

[0085] Alternatively, after the exhaust units 31 of the first row are installed, the second row, the third row and the fourth row are arranged in a staggered manner; then, the exhaust units 31 of the fifth row, the sixth row, the seventh row and the eighth row are arranged according to the distribution of the first row, the second row, the third row and the fourth row, and so on. For details, please refer to FIG. 7. At this time, the distance Z3 between the fifth row and the first row can be four times the distance Z0 between the first row and the second row, and the distance X0 between two adjacent exhaust units 31 in the first row can be four times the distance X1 between two adjacent exhaust units 31 in the first row and the second row in the second direction P.

[0086] Of course, the punching method of this embodiment is not limited to the above punching methods, as long as the exhaust units 31 in at least two adjacent unit rows 32 are staggered. At the same time, in the above preparation process, a laser punching device 200 can be used. As shown in FIG8 , when the laser punching device 200 is punching, the roller 300 stops conveying the conductive layer 30 .

[0087] The first direction T and the second direction P intersect with each other, and both intersect with the thickness direction H. Specifically, in some embodiments, the first direction T, the second direction P, and the thickness direction H are perpendicular to each other. In addition, 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 punching method can refer to FIG. 9.

[0088] 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, so that the exhaust range is larger and the exhaust effect is more uniform.

[0089] According to some embodiments of the present application, optionally, referring to FIG. 4 , in each unit row 32 , the distance between two adjacent exhaust units 31 is denoted as X, wherein 10 mm≤X≤100 mm.

[0090] The spacing X between two adjacent exhaust units 31 may be between 10 mm and 100 mm. For example, the spacing 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.

[0091] With such a 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.

[0092] According to some embodiments of the present application, optionally, the spacing X also satisfies the condition: 20 mm ≤ X ≤ 50 mm.

[0093] 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.

[0094] With such a 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.

[0095] According to some embodiments of the present application, optionally, referring 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.

[0096] 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.

[0097] In the first direction T, the exhaust units 31 in the two 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.

[0098] With such a 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.

[0099] According to some embodiments of the present application, optionally, referring to FIG. 4 , the spacing Z also satisfies the condition: 20 mm ≤ Z ≤ 50 mm.

[0100] The distance Z between two adjacent exhaust units 31 may be between 20 mm and 50 mm. For example, the distance Z may be, but is not limited to, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc.

[0101] With such a 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 take into account both structural strength and gas exhaust effect.

[0102] According to some embodiments of the present application, optionally, the first direction T is configured as a length direction of the conductive layer 30 , and the second direction P is configured as a width direction of the conductive layer 30 .

[0103] The length direction of the conductive layer 30 can also be understood as the running direction of the conductive layer 30. For example, before cutting to the required size, the conductive layer 30 is continuously transported forward by the conveying roller, and the running direction can be regarded as the length direction of the conductive layer 30. Of course, the running direction of the conductive layer 30 can also be the direction in which the conductive layer 30 is continuously transported forward during the punching process.

[0104] 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.

[0105] According to some embodiments of the present application, optionally, referring to FIG. 10 , the penetration direction of the exhaust unit 31 is inclined relative to the thickness direction H.

[0106] The penetration direction of the exhaust unit 31 is inclined relative to the thickness direction H, which means that when the exhaust unit 31 is formed, it penetrates the conductive layer 30 at a certain angle, such as by punching. It should be noted that when there are multiple exhaust units 31, some of the exhaust units 31 can be designed as inclined holes, or all of them can be designed as inclined holes.

[0107] 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, and effectively reduce the glue 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, making the bonding force stronger, which is beneficial to improving the overall structural strength of the composite current collector 100.

[0108] According to some embodiments of the present application, optionally, referring to FIG. 10 , there is an acute angle between the penetration direction of the exhaust unit 31 and the thickness direction H, which is denoted as θ, wherein 30°≤θ≤80°.

[0109] 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°, etc.

[0110] With such a 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 .

[0111] According to some embodiments of the present application, optionally, the acute angle θ also satisfies the condition: 50°≤θ≤70°.

[0112] 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°, etc.

[0113] With such a design, the acute angle θ is controlled between 50° and 70°, so that the exhaust unit 31 can maintain a certain inclination on the conductive layer 30; and the processing difficulty of the exhaust unit 31 can be reduced, effectively taking into account both the anti-overflow glue effect and the processing convenience.

[0114] According to some embodiments of the present application, optionally, 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, wherein 1 nm≤D1≤5000 nm.

[0115] 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.

[0116] To this end, the diameter of the exhaust unit 31 can be between 1nm and 5000nm. For example, the diameter of the exhaust unit 31 can be 1nm, 10nm, 100nm, 1000nm, 2000nm, 3000nm, 4000nm, 5000nm, etc.

[0117] With such a design, the diameter of the exhaust unit 31 is controlled between 1 nm and 5000 nm, so that the composite current collector 100 is not prone to gel leakage during preparation; and it is also beneficial to exhaust between the conductive layer 30 and the substrate 10, thereby improving the bonding strength between the two.

[0118] According to some embodiments of the present application, optionally, the diameter D1 also satisfies the condition: 50 nm ≤ D1 ≤ 300 nm.

[0119] 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.

[0120] With such a 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.

[0121] According to some embodiments of the present application, optionally, an adhesive layer 20 is provided 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 .

[0122] The adhesive layer 20 refers to a layer of structure bonded between the conductive layer 30 and the substrate 10. During the preparation process, a part of the structure on the adhesive layer 20 may penetrate into the exhaust unit 31. Meanwhile, during the processing of the exhaust unit 31, the exhaust unit 31 penetrates the conductive layer 30, but does not extend into the adhesive layer 20, let alone onto the substrate 10.

[0123] There are many choices 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 multifunctional isocyanate and polyester polyol compounds, 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 one or more of a composition containing multifunctional isocyanate and polyester polyol compounds and polyurethane. Among them, the polyurethane includes one or more of thermoplastic polyurethane and reactive polyurethane.

[0124] 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 beneficial to improving the bonding force between structures.

[0125] According to some embodiments of the present application, optionally, referring to FIG. 3 , the thickness of the adhesive layer 20 in the thickness direction H is recorded as D2, wherein 200 nm≤D2≤1500 nm.

[0126] 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.

[0127] In this way, the thickness of the glue layer 20 is controlled between 200 nm and 1500 nm, so as to minimize the input of glue while meeting the requirement of effective bonding, and control the thickness of the composite current collector 100 .

[0128] According to some embodiments of the present application, optionally, the thickness D2 also satisfies the condition: 300nm≤D2≤700nm.

[0129] 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, etc.

[0130] 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 .

[0131] According to some embodiments of the present application, optionally, referring to FIG. 3 , the thickness of the substrate 10 in the thickness direction H is denoted as D3, wherein 2µm≤D3≤10µm.

[0132] The thickness D3 may be between 2µm and 10µm. For example, the thickness D3 may be, but is not limited to, 2µm, 3µm, 4µm, 5µm, 6µm, 7µm, 8µm, 9µm, 10µm, etc.

[0133] 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, which is convenient for improving the energy density of the battery.

[0134] According to some embodiments of the present application, optionally, the thickness D3 also satisfies the condition: 3µm≤D3≤8µm.

[0135] The thickness D3 may be between 3µm and 8µm, for example, the thickness D3 may be, but is not limited to, 3µm, 4µm, 5µm, 6µm, 7µm, 8µm, etc.

[0136] 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 the structural strength and thickness.

[0137] According to some embodiments of the present application, the present application provides a pole piece, which includes any of the composite current collectors 100 described above.

[0138] According to some embodiments of the present application, the present application provides an electrode assembly, which includes the above electrode piece.

[0139] According to some embodiments of the present application, the present application provides a secondary battery, and the secondary battery includes the above electrode assembly.

[0140] According to some embodiments of the present application, the present application provides an electric device, which includes the above secondary battery.

[0141] According to some embodiments of the present application, please refer to FIG. 3 to FIG. 10 , the present application provides a composite current collector 100, including a substrate 10 and a conductive layer 30 respectively bonded to both sides of the substrate 10 through a glue layer 20, and a gas exhaust unit 31 is provided on the conductive layer 30. In the preparation of the composite current collector 100, by pressing the conductive layer 30, not only the conductive layer 30 and the substrate 10 are closely combined, but also the gas in the glue layer 20 is discharged from the gas exhaust unit 31, so that the prepared composite current collector 100 has qualified bonding force, and the problem of sporadic shedding on the conductive layer 30 is also solved.

[0142] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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.

[0143] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A composite current collector, characterized in that: The composite current collector comprises: A substrate (10); A conductive layer (30) bonded to at least one side of the substrate (10); Wherein, an exhaust unit (31) is provided on the conductive layer (30), and at least a portion of the exhaust unit (31) penetrates the conductive layer (30) in the thickness direction (H) of the composite current collector.

2. The composite current collector according to claim 1, characterized in that: The exhaust unit (31) comprises a plurality of 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, characterized in that: The distribution density of the exhaust units (31) on the conductive layer (30) is denoted as n, where 1 unit / dm 2 ≤n≤100pcs / dm 2 .

4. The composite current collector according to claim 3, characterized in that: The distribution density n also satisfies the following conditions: 4 pieces / dm 2 ≤n≤25pcs / dm 2 .

5. The composite current collector according to claim 2, characterized in that: 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 and distributed along a second direction (P); Among them, in at least two adjacent groups of the unit rows (32), the exhaust units (31) in one group of the unit rows (32) and the exhaust units (31) in the other group of the unit rows (32) are staggered in the first direction (T), the first direction (T) intersects with the second direction (P), and the plane formed intersects with the thickness direction (H).

6. The composite current collector according to claim 5, characterized in that: 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, characterized in that: The spacing X also satisfies the condition: 20 mm ≤ X ≤ 50 mm.

8. The composite current collector according to claim 5, characterized in that: In two adjacent groups of the unit rows (32), a spacing in the first direction (T) between an exhaust unit (31) in one group of the unit rows (32) and a corresponding exhaust unit (31) in the other group of the unit rows (32) is denoted as Z, wherein 0 mm ≤ Z ≤ 100 mm.

9. The composite current collector according to claim 8, characterized in that: The spacing Z also satisfies the condition: 20mm≤Z≤50mm.

10. The composite current collector according to claim 5, characterized in that: The first direction (T) is configured as a length direction of the conductive layer (30), and the second direction (P) is configured as a width direction of the conductive layer (30).

11. The composite current collector according to any one of claims 1 to 10, characterized in that: The penetration direction of the exhaust unit (31) is arranged to be inclined relative to the thickness direction (H).

12. The composite current collector according to claim 11, characterized in that: An acute angle is formed between the penetration direction of the exhaust unit (31) and the thickness direction (H), and is denoted as θ, wherein 30°≤θ≤80°.

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

14. The composite current collector according to any one of claims 1 to 10, characterized in that: The exhaust unit (31) is constructed 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, characterized in that: The diameter D1 also satisfies the condition: 50 nm ≤ D1 ≤ 300 nm.

16. The composite current collector according to any one of claims 1 to 10, characterized in that: An adhesive layer (20) is provided between the conductive layer (30) and the substrate (10), and one end of the exhaust unit (31) extends to a side surface of the conductive layer (30) facing the adhesive layer (20).

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

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

19. The composite current collector according to any one of claims 1 to 10, characterized in that: The thickness of the substrate (10) in the thickness direction (H) is denoted as D3, wherein 2µm≤D3≤10µm.

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

21. A pole piece, characterized in that: The pole piece comprises the composite current collector according to any one of claims 1-20.

22. An electrode assembly, characterized in that: The electrode assembly comprises the electrode piece according to claim 21.

23. A secondary battery, characterized in that: The secondary battery includes the electrode assembly of claim 22 .

24. An electrical device, characterized in that: The electric device comprises the secondary battery according to claim 23.

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