Extrusion mechanism, composite current collector preparation device and method and battery production system

Abstract

The invention relates to an extrusion mechanism, a composite current collector preparation device, a composite current collector preparation method and a battery production system.An air exhaust hole is formed in a supporting roller and / or the roller surface of an extrusion roller, when the extrusion roller and the supporting roller are matched to extrude a conductive layer and a base material layer which are bonded with each other, air exhaust can be conducted on the surface of the conductive layer and / or the base material layer through the air exhaust hole, and therefore the surface of the conductive layer and / or the base material layer is extruded. Therefore, the conductive layer and the substrate layer are squeezed and sucked at the same time, gas escape between the conductive layer and the substrate layer is accelerated, bubbles between the conductive layer and the substrate layer are reduced, the binding force between the conductive layer and the substrate layer is improved, the stripping risk of the conductive layer is reduced, and the performance of the battery is improved.

Description

Technical Field

[0001] The present application relates to the technical field of battery production, and particularly to an extrusion mechanism, a composite current collector preparation device, a method and a battery production system. Background Art

[0002] The current collector is an important component in a 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 increasing requirements for battery reliability, composite current collectors have also been proposed. A composite current collector refers to a structure obtained by combining a conductive layer and a polymer substrate layer. When the conductive layer and the polymer substrate layer are bonded with glue, due to the structural design limitations of traditional equipment, problems such as easy peeling of the conductive layer and a decrease in bonding force occur, resulting in a decrease in battery performance.

[0003] The above statements are only used to provide background technical information related to the present application and do not necessarily constitute prior art. Summary of the Invention

[0004] Based on this, it is necessary to provide an extrusion mechanism, a composite current collector preparation device, a method and a battery production system to improve the combination between the conductive layer and the substrate layer, reduce the risk of peeling, and enhance battery performance.

[0005] In a first aspect, the present application provides an extrusion mechanism. The extrusion mechanism includes: a support roller; an extrusion roller for extruding the mutually bonded conductive layer and substrate layer with the support roller; wherein, at least one of the support roller and the extrusion roller is provided with air suction holes on the roller surface arranged along the circumferential direction of its own axis for communicating with a suction device.

[0006] In the above extrusion mechanism, air suction holes are provided on the roller surface of the support roller and / or the extrusion roller. When the extrusion roller and the support roller cooperate to extrude the mutually bonded conductive layer and substrate layer, air can be sucked from the air suction holes on the surface of the conductive layer and / or the substrate layer, so that the conductive layer and the substrate layer are extruded while being sucked, accelerating the escape of gas between the conductive layer and the substrate layer, reducing the bubbles between the conductive layer and the substrate layer, improving the bonding force between the conductive layer and the substrate layer, reducing the peeling risk of the conductive layer, and being beneficial to enhancing battery performance.

[0007] In some embodiments, the support roller and / or the extrusion roller having air suction holes are provided with air flow channels extending along their respective axis directions, and the air flow channels are communicated with the corresponding air suction holes. Designed in this way, the introduction of the air flow channels facilitates the connection between the air suction holes and an external suction device to achieve stable suction of the conductive layer and / or the substrate layer.

[0008] In some embodiments, in the support roller or the extrusion roller, there are more than two air extraction holes, and at least some of the air extraction holes are spaced apart. With such a design, by spacing apart at least some of the air extraction holes, the suction range can be expanded, making the exhaust between the conductive layer and the substrate layer more uniform, which is beneficial to improving the lamination quality of the composite current collector.

[0009] In some embodiments, among the spaced-apart air extraction holes, the distance between two adjacent air extraction holes is denoted as L, where 5 mm ≤ L ≤ 50 mm;

[0010] Optionally, the condition that the distance L also satisfies is: 10 mm ≤ L ≤ 30 mm.

[0011] With such a design, by controlling the distance L between 5 mm and 50 mm, the design of the air extraction holes can effectively balance the air extraction effect and the lamination quality between the conductive layer and the substrate layer.

[0012] In some embodiments, in the support roller or the extrusion roller, there are more than two air extraction holes, and at least some of the air extraction holes are spaced apart around the outer periphery of the corresponding axis. With such a design, by spacing apart at least some of the air extraction holes around the outer periphery of the axis, the circumferential direction of the support roller or the extrusion roller has a suction function, so that when the support roller or the extrusion roller rotates, it can suck the conductive layer or the substrate layer, improving the exhaust effect.

[0013] In some embodiments, the hole area of the air extraction holes on the roller surface of the support roller or the extrusion roller is denoted as S, where 0.00785 mm 2 ≤ S ≤ 0.785 mm 2 ;

[0014] Optionally, the condition that the hole area S also satisfies is: 0.1 mm 2 ≤ S ≤ 0.5 mm 2 ;

[0015] Optionally, the air extraction holes are configured as circular holes, and the diameter of the air extraction holes is: 0.1 mm to 1 mm.

[0016] With such a design, by controlling the hole area of the air extraction holes between 0.00785 mm 2 and 0.785 mm 2 effective exhaust can be achieved; at the same time, the probability of glue overflow or imprinting during the lamination process can be reduced, improving the lamination quality.

[0017] In some embodiments, there are more than two extrusion rollers, and all the extrusion rollers are spaced apart around the outer periphery of the axis of the support roller. With such a design, by introducing more than two extrusion rollers, the same part of the conductive layer and the substrate layer is extruded multiple times, strengthening the lamination effect and making the conductive layer and the substrate layer tightly combined; at the same time, the exhaust effect is also strengthened, reducing the probability of the conductive layer peeling off.

[0018] In some embodiments, a lamination path for the conductive layer and the substrate layer to pass through is formed between all the extrusion rollers and the support rollers. The central angle corresponding to the lamination path on the support roller is denoted as θ, where 180° ≤ θ < 360°;

[0019] Optionally, the condition that the central angle θ also satisfies is: 200° ≤ θ ≤ 300°.

[0020] With such a design, controlling the central angle corresponding to the lamination path to be greater than or equal to 180° can increase the running belt wrap angle of the conductive layer and the substrate layer on the support roller, which is beneficial to improving the lamination and exhaust effects of the composite current collector.

[0021] In some embodiments, the cross-sectional area of at least one extrusion roller in a plane perpendicular to its own axis gradually increases from one end of the extrusion roller to the other end and then gradually decreases. With such a design, at least one extrusion roller is designed with a larger size in the middle part and smaller sizes at both ends, making the conductive layer and the substrate layer more flat during the lamination process; at the same time, it is also beneficial for the bubbles in the glue to transfer to both ends, improving the exhaust effect.

[0022] In some embodiments, in a plane passing through the axis of the extrusion roller, the projection of the roller surface of the extrusion roller includes at least one contour line. The angle between the contour line and the axis of the extrusion roller is denoted as β, where 1° ≤ β ≤ 5°;

[0023] Optionally, the condition that the angle β also satisfies is: 2° ≤ β ≤ 4°.

[0024] With such a design, reasonably controlling the angle β between 1° and 5° makes the flattening effect of the conductive layer and the substrate layer better, improving the lamination quality.

[0025] In some embodiments, the extrusion mechanism further includes a heating component, which is used to heat the roller surfaces of the support roller and / or the extrusion roller. With such a design, introducing the heating component can increase the surface temperature on the conductive layer and / or the substrate layer, soften the glue, and improve the bonding performance; at the same time, it is also convenient for the bubbles in the glue to escape more easily, improving the exhaust effect.

[0026] In some embodiments, both the support roller and the extrusion roller include more than two. All the support rollers are arranged in parallel and spaced apart, and each support roller cooperates with at least one extrusion roller. With such a design, introducing more than two support rollers enables the conductive layer and the substrate layer to be laminated on different support rollers in sequence, enhancing the bonding strength and improving the stability of the structure.

[0027] In a second aspect, the present application provides a composite current collector manufacturing device, including the extrusion mechanism according to any one of the above.

[0028] In some embodiments, the composite current collector preparation device further includes a punching mechanism. On the tape running path of the base material layer or the conductive layer, the punching mechanism is located at the upstream end of the extrusion mechanism and is used to punch the conductive layer and / or the base material layer. With such a design, through the punching mechanism, holes are formed in the conductive layer and / or the base material layer, facilitating the escape of gas from the holes during pressing, further improving the exhaust effect, and thus making the bonding between the conductive layer and the base material layer more stable.

[0029] In some embodiments, the composite current collector preparation device further includes a gluing mechanism. On the tape running path of the base material layer or the conductive layer, the gluing mechanism is located at the upstream end of the extrusion mechanism and is used to apply glue to the conductive layer and / or the base material layer. With such a design, through the gluing mechanism, glue is stably applied to the conductive layer and / or the base material layer, making the conductive layer and the base material layer stably bonded.

[0030] In some embodiments, the composite current collector preparation device further includes a surface treatment mechanism. The surface treatment mechanism is located at the upstream end of the gluing mechanism and is used to improve the surface energy of the conductive layer and / or the base material layer. With such a design, through the surface treatment mechanism, the surface energy of the conductive layer and / or the base material layer is improved, enhancing the adhesion to the glue, making the conductive layer and the base material layer stably bonded, and improving the stability of the structure.

[0031] In some embodiments, the composite current collector preparation device further includes a baking mechanism. The baking mechanism is located at the downstream end of the gluing mechanism and is used to dry the conductive layer and / or the base material layer after gluing. With such a design, by introducing the baking mechanism, the volatilization of the solvent in the glue is accelerated, the glue is softened, the bonding performance is improved, and thus the bonding force between the conductive layer and the base material layer is increased.

[0032] In some embodiments, the composite current collector preparation device further includes a passivation mechanism. The passivation mechanism is used to passivate at least one surface of the conductive layer. With such a design, by introducing a passivation layer, the corrosion resistance of the conductive layer under long-term cyclic storage of the electrolyte can be improved, and the peeling risk of the composite current collector under long-term immersion in the electrolyte can be reduced; at the same time, the adhesion of the conductive layer to the glue is also improved, further enhancing the stability of the structure.

[0033] In some embodiments, the composite current collector preparation device further includes a first unwinding mechanism and a second unwinding mechanism. The first unwinding mechanism and the second unwinding mechanism are respectively used to release the conductive layer and the base material layer correspondingly. With such a design, by introducing the first unwinding mechanism and the second unwinding mechanism, the preparation of the composite current collector can be carried out continuously and stably.

[0034] In some embodiments, the composite current collector preparation device further includes a winding mechanism. The winding mechanism is used to wind the pressed conductive layer and base material layer output by the extrusion mechanism. With such a design, through the winding mechanism, it is convenient to store the composite current collector.

[0035] In a third aspect, the present application provides a method for preparing a composite current collector, the method comprising the following steps: perforating the surface of the substrate layer and / or the conductive layer through; applying glue to the surface of the substrate layer and / or the conductive layer; laminating and bonding the substrate layer and the conductive layer; extruding and evacuating the laminated substrate layer and conductive layer.

[0036] In some embodiments, the step of extruding and evacuating the laminated substrate layer and conductive layer includes: passing the laminated substrate layer and conductive layer between a support roller and an extrusion roller; extruding and conveying the substrate layer and conductive layer through the cooperation of the support roller and the extrusion roller; evacuating the air suction holes on the roller surfaces of the support roller and / or the extrusion roller. With such a design, the support roller and the extrusion roller are introduced, so that during the pressing process, extrusion and suction are achieved simultaneously, accelerating the discharge of gas from the holes in the conductive layer and / or the substrate layer, improving the exhaust effect, and enabling stable bonding between the conductive layer and the substrate layer.

[0037] In some embodiments, in the step of extruding and conveying the substrate layer and conductive layer through the cooperation of the support roller and the extrusion roller, there are more than two extrusion rollers, and the substrate layer and the conductive layer sequentially pass between each extrusion roller and the support roller, and along the running direction of the substrate layer, the pressure applied by each extrusion roller on the same support roller gradually increases. With such a design, more than two extrusion rollers are introduced to extrude the same part of the conductive layer and the substrate layer multiple times, strengthening the pressing effect and enabling the conductive layer and the substrate layer to be tightly combined; at the same time, the exhaust effect is also strengthened, reducing the probability of the conductive layer peeling off.

[0038] In some embodiments, after the step of applying glue to the surface of the substrate layer and / or the conductive layer, the method further includes: baking the substrate layer and / or the conductive layer coated with glue. With such a design, the baking process is introduced, which can reduce the generation of bubbles; at the same time, it is also beneficial to the bonding performance of the glue, enabling the conductive layer and the substrate layer to be tightly connected.

[0039] In some embodiments, the baking parameters include at least one of the following: the blowing speed of the air on the surface of the substrate layer and / or the conductive layer is 0.5m 3 / min to 5m 3 / min; the blowing time of the air on the surface of the substrate layer and / or the conductive layer is 2S to 10S; the baking temperature is 80°C to 150°C. Thus, by reasonably controlling the baking temperature, blowing speed, and blowing time, the residual solvent in the glue is further reduced, and the bonding performance of the glue is improved, thereby enhancing the bonding force between the conductive layer and the substrate layer.

[0040] In some embodiments, before the step of applying glue to the surface of the substrate layer and / or the conductive layer, it further includes: corona treating the surface of the substrate layer and / or the conductive layer. With such a design, the corona step is introduced to improve the corrosion resistance of the conductive layer under long-term cyclic storage of the electrolyte and reduce the peeling risk of the composite current collector under long-term immersion in the electrolyte; at the same time, it also improves the adhesion of the conductive layer to the glue and further enhances the structural stability.

[0041] In a second aspect, the present application provides a battery production system, and the battery production system includes the composite current collector manufacturing device according to any one of the above. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a schematic structural diagram of the extrusion mechanism described in some embodiments of the present application.

[0043] Figure 2 It is a schematic structural diagram of the support roller described in some embodiments of the present application.

[0044] Figure 3 It is a schematic structural diagram of the extrusion roller described in some embodiments of the present application.

[0045] Figure 4 It is a schematic structure of the composite current collector manufacturing device described in some embodiments of the present application Figure 1 。

[0046] Figure 5 It is a schematic structure of the composite current collector manufacturing device described in some embodiments of the present application Figure 2 。

[0047] Figure 6 It is a schematic structure of the composite current collector manufacturing device described in some embodiments of the present application Figure 3 。

[0048] Figure 7 It is the process flow of the composite current collector manufacturing method described in some embodiments of the present application Figure 1 。

[0049] Figure 8 It is the process flow of the composite current collector manufacturing method described in some embodiments of the present application Figure 2 。

[0050] Figure 9 It is the process flow of the composite current collector manufacturing method described in some embodiments of the present application Figure 3 。

[0051] 100. Extrusion mechanism; 10. Support roller; 11. Air extraction hole; 12. Air flow channel; 13. Pressing path; 20. Extrusion roller; 21. Contour line; 30. Punching mechanism; 40. Glue application mechanism; 50. Baking mechanism; 60. Surface treatment mechanism; 70. Passivation mechanism; 80. First unwinding mechanism; 81. Second unwinding mechanism; 90. Rewinding mechanism; 200. Substrate layer; 300. Conductive layer. Detailed implementation manner

[0052] To make the above objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed implementation manner of the present application in conjunction with the accompanying drawings. Many specific details are set forth in the following description 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 departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0053] In the description of the present application, it should be understood that if there are terms such as "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., the orientation or positional relationship indicated by these terms is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0054] In addition, if there are terms such as "first" and "second", these terms are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present application, if there is a term "plurality", the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically defined.

[0055] In the present application, unless otherwise clearly defined and limited, if there are terms such as "installation", "connection", "connection", "fixation", etc., these terms should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific circumstances.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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 arranged on a substrate layer, for example: the conductive layer is bonded to the substrate layer by glue.

[0060] Since there will be more or less residual gas in the glue, when the conductive layer is bonded and pressed onto the substrate layer, it is difficult for the gas to escape from the glue, resulting in incomplete adhesion between the substrate layer and the conductive layer. The bonding force between the two is poor, resulting in the risk of sporadic peeling of the conductive layer.

[0061] Based on this, in order to effectively solve the problem that the conductive layer on the surface of the composite current collector has a peeling risk due to adhesive bonding, the present application provides an extrusion mechanism. An air extraction hole is provided on the roll surface of the support roll and / or the extrusion roll. When the extrusion roll and the support roll cooperate to extrude the mutually bonded conductive layer and the substrate layer, the surface of the conductive layer and / or the substrate layer can be evacuated through the air extraction hole, so that the conductive layer and the substrate layer are extruded while being sucked, accelerating the escape of gas between the conductive layer and the substrate layer, reducing the bubbles between the conductive layer and the substrate layer, improving the bonding force between the conductive layer and the substrate layer, reducing the peeling risk of the conductive layer, and being beneficial to improving the battery performance.

[0062] According to some embodiments of the present application, please refer to Figure 1 , the present application provides an extrusion mechanism 100. The extrusion mechanism 100 includes: a support roll 10 and an extrusion roll 20. Between the extrusion roll 20 and the support roll 10 is used to extrude the mutually bonded conductive layer 300 and the substrate layer 200; wherein, on the roll surface of at least one of the support roll 10 and the extrusion roll 20 arranged circumferentially around its own axis, there is provided an air extraction hole 11 for communicating with a suction device.

[0063] The support roll 10 and the extrusion roll 20 respectively refer to the structures acting on opposite sides of the composite current collector, so that the composite current collector is subjected to pressure in its own thickness direction to achieve stable bonding of the conductive layer 300 and the substrate layer 200. Among them, both the support roll 10 and the extrusion roll 20 can be in a cylindrical structure.

[0064] To realize the forward transportation and continuous pressing of the conductive layer 300 and the substrate layer 200, both the support roll 10 and the extrusion roll 20 can rotate around their respective axes, and their rotation directions are opposite. At the same time, the linear speed of the support roll 10 and the linear speed of the extrusion roll 20 can be kept consistent, so that during pressing, the surface of the composite current collector will not wrinkle or crack due to inconsistent roll linear speeds.

[0065] The suction device refers to a device that provides power for sucking the surface of the conductive layer 300 and / or the substrate layer 200. For example: it can be but is not limited to a vacuum pump. The connection method between the suction device and the air extraction hole 11 can adopt a hose connection, or a flow channel can be provided on the support roll 10 or the extrusion roll 20, and the suction device and the air extraction hole 11 are connected by using the flow channel.

[0066] During the pressing process, the air extraction hole 11 sucks the surface of the conductive layer 300 and / or the substrate layer 200 under the action of the suction device to accelerate the escape speed of gas during pressing. To enhance the suction effect, after pressing, holes can be drilled on the surface of the conductive layer 300 and / or the substrate layer 200. In this way, under the action of suction, gas can easily escape from the holes on the conductive layer 300 or the substrate layer 200, enhancing the exhaust effect.

[0067] Among them, when drilling holes in the conductive layer 300 and / or the substrate layer 200, there can be various designs for the size and distribution of the formed holes. For example: the hole diameter on the conductive layer 300 and / or the substrate layer 200 can be between 50 μm and 500 μm, which can meet the escape of gas during the lamination process. At the same time, it can also reduce the overflow of glue from the holes. On the contrary, it can enhance the bonding force between the conductive layer 300 or the substrate layer 200 and the glue. The hole pitch on the conductive layer 300 and / or the substrate layer 200 can be controlled to be 5 mm to 50 mm, etc.

[0068] In addition, the lamination of the composite current collector can be carried out by one-step lamination or two-step lamination. Among them, one-step lamination means bonding two conductive layers 300 to the two surfaces of the substrate layer 200 through glue, and threading the combined structure between the support roller 10 and the extrusion roller 20. Two-step lamination means bonding the conductive layer 300 to one surface of the substrate layer 200 through glue and threading it between the support roller 10 and the extrusion roller 20; after lamination, bonding the other conductive layer 300 to the other surface of the substrate layer 200, and after bonding, threading it between the support roller 10 and the extrusion roller 20 again.

[0069] It should also be noted that the substrate layer 200 refers to the supporting structure in the composite current collector, and its material can be selected from at least one of organic polymer insulating materials, inorganic insulating materials, and composite materials. 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-phenylenediamine terephthalamide), polypropylene styrene, polyoxymethylene, epoxy resin, phenolic resin, polytetrafluoroethylene, polyvinylidene fluoride, silicone rubber, and polycarbonate. The inorganic insulating material is preferably at least one of alumina, 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.

[0070] The conductive layer 300 refers to a structure with conductive function, which can collect the current generated by the active material layer for external output. At the same time, on the current collector, the side of the conductive layer 300 facing away from the substrate layer 200 is used for coating active materials, such as: lithium cobaltate, lithium manganate, lithium nickelate, lithium iron phosphate, ternary materials, etc. can be coated, or graphite, silicon oxide, etc. can also be coated. Among them, the conductive layer 300 can be copper foil or aluminum foil, etc.

[0071] The conductive layer 300 and the substrate layer 200 are adhesively bonded to each other, and there is glue between them. There are various choices for the material of this glue. For example, the material of the glue can include a composition containing polyfunctional 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 copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, acrylic resin, polycarbonate, polyamide, or one or more of them. Preferably, it is one or more of a composition containing polyfunctional isocyanate and polyester polyol compounds and polyurethane. Among them, polyurethane includes one or more of thermoplastic polyurethane and reactive polyurethane.

[0072] With such a design, the conductive layer 300 and the substrate layer 200 are squeezed and suctioned at the same time, which speeds up the escape of gas between the conductive layer 300 and the substrate layer 200, reduces the bubbles between the conductive layer 300 and the substrate layer 200, improves the bonding force between the conductive layer and the substrate layer 200, reduces the peeling risk of the conductive layer 300, and is beneficial to improving the battery performance.

[0073] According to some embodiments of the present application, optionally, please refer to Figure 1 , on the support roller 10 and / or the pressing roller 20 having air extraction holes 11, there are air flow channels 12 extending along their respective axial directions, and the air flow channels 12 communicate with the corresponding air extraction holes 11.

[0074] The air flow channel 12 refers to a structure that can achieve the connection between the suction device and the air extraction hole 11. It extends along the axial direction and can be conveniently connected to an external air extraction device. For example, a rotatable sealing interface can be provided at one end of the air flow channel 12, and the sealing interface is connected to the suction device. In this way, on the premise of not affecting the rotation of the support roller 10 or the pressing roller 20, a stable negative pressure environment is provided for the air extraction hole 11. At the same time, an oil seal can be used between the sealing interface and the inner wall of the channel flow.

[0075] With such a design, the introduction of the air flow channel 12 facilitates the connection between the air extraction hole 11 and an external air extraction device, and realizes the stable suction of the conductive layer 300 and / or the substrate layer 200.

[0076] According to some embodiments of the present application, optionally, please refer to Figure 1 , in the support roller 10 or the pressing roller 20, there are more than two air extraction holes 11, and at least some of the air extraction holes 11 are spaced apart.

[0077] In the support roller 10 or the pressing roller 20, at least some of the air extraction holes 11 can be spaced apart along their respective axes, and reference can be made to Figure 2 ; they can also be spaced apart circumferentially around their respective circumferences, and reference can be made to Figure 1Meanwhile, when the support roller 10 or the squeezing roller 20 is provided with a ventilation channel 12 , each of the air extraction holes 11 is communicated with the ventilation channel 12 .

[0078] The shape of the air extraction hole 11 can be designed in various ways, for example, it can be a regular shape such as a circle, an ellipse, a triangle, a square, a pentagon, etc.; it can also be an irregular shape.

[0079] With such a design, at least part of the exhaust holes 11 are distributed at intervals, which can expand the range of the exhaust, make the exhaust between the conductive layer 300 and the substrate layer 200 more uniform, and help improve the pressing quality of the composite current collector.

[0080] According to some embodiments of the present application, optionally, please refer to Figure 1 and Figure 2 Among the air extraction holes 11 distributed at intervals, the distance between two adjacent air extraction holes 11 is recorded as L, where 5mm≤L≤50mm.

[0081] Two adjacent air extraction holes 11 may be spaced along the axis direction of the support roller 10 or the squeeze roller 20, and the distance between the two is a straight line distance. If the two adjacent air extraction holes 11 are spaced along the circumference of the support roller 10 or the squeeze roller 20, since the support roller 10 and the squeeze roller 20 are both or approximately cylindrical, the distance between the two is an arc distance between the two air extraction holes 11. In order to obtain the distance L between two adjacent air extraction holes 11, the center line between the two air extraction holes 11 can be connected, and the line is on the surface of the support roller 10 or the squeeze roller 20 and is located between the two air extraction holes 11 to form a straight line segment or a curved line segment, and the straight line segment or the curved line segment is the distance L.

[0082] If the spacing L is too large, there will be no suction effect in some areas of the conductive layer 300 or the substrate layer 200; if it is too small, it will not only affect the structural strength of the squeezing roller 20 or the supporting roller 10, but also leave an imprint on the conductive layer 300 or the substrate layer 200, affecting product quality.

[0083] To this end, the spacing L may be between 5 mm and 50 mm, for example, but not limited to 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 35 mm, 40 mm, 45 mm, 50 mm, etc. Of course, in some other embodiments, the spacing L may be between 10 mm ≤ L ≤ 30 mm, for example, but not limited to 10 mm, 12 mm, 15 mm, 18 mm, 20 mm, 22 mm, 25 mm, 28 mm, 30 mm, etc.

[0084] With such a design, the spacing L is controlled between 5 mm and 50 mm, so that the design of the air extraction holes 11 can effectively take into account both the air extraction effect and the lamination quality between the conductive layer 300 and the substrate layer 200 .

[0085] According to some embodiments of the present application, please refer to Figure 1 , optionally, in the support roller 10 or the extrusion roller 20, there are more than two air extraction holes 11, and at least part of the air extraction holes 11 are distributed at intervals around the outer periphery of the corresponding axis.

[0086] The air extraction holes 11 are distributed at intervals around the outer periphery of the corresponding axis, which can be understood as: when more than two air extraction holes 11 are provided on the support roller 10, at least part of the air extraction holes 11 are distributed at intervals around the outer periphery of the axis of the support roller 10; when more than two air extraction holes 11 are provided on the extrusion roller 20, at least part of the air extraction holes are distributed at intervals around the outer periphery of the axis of the extrusion roller 20; when more than two air extraction holes 11 are provided on both the support roller 10 and the extrusion roller 20, the air extraction holes 11 are distributed at intervals around the outer peripheries of their respective corresponding axes.

[0087] With such a design, at least part of the air extraction holes 11 are distributed at intervals around the outer periphery of the axis, so that the circumferences of the support roller 10 or the extrusion roller 20 both have a suction function, and thus when the support roller 10 or the extrusion roller 20 rotates, it can suck the conductive layer 300 or the base material layer 200, improving the exhaust effect.

[0088] According to some embodiments of the present application, optionally, please refer to Figure 2 , the hole area of the air extraction holes 11 on the roller surface of the support roller 10 or the extrusion roller 20 is denoted as S, where 0.00785 mm 2 ≤S≤0.785 mm 2 .

[0089] The shape of the air extraction holes 11 can be designed into regular shapes, such as circular, elliptical, square, etc.; it can also be designed into irregular shapes. The value of the hole area of the air extraction holes 11 not only affects the exhaust effect, but also affects the lamination quality of the composite current collector. For example: if the hole area of the air extraction holes 11 is too small, it is easy to cause blockage and the exhaust cannot be achieved; if the hole area of the air extraction holes 11 is too large, not only is it easy to overflow glue, but also imprints will be formed on the surface of the conductive layer 300 or the base material layer 200.

[0090] Therefore, the hole area S of the air extraction holes 11 can be controlled between 0.00785 mm 2 ~0.785 mm 2 , for example: it can be but not limited to 0.00785 mm 2 , 0.008 mm 2 , 0.01 mm 2 , 0.1 mm 2 , 0.19625 mm 2 , 0.2 mm 2 , 0.3 mm 2 , 0.4 mm 2 , 0.5 mm 2, 0.6 mm 2 , 0.7 mm 2 , 0.785 mm 2 When the air extraction hole 11 is a circular hole, the aperture of the air extraction hole 11 can be 0.1 mm to 1 mm, for example: the aperture can be but is not limited to 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, etc.

[0091] In addition, in some other embodiments, the hole area S can also be between 0.1 mm 2 and 0.5 mm 2 Of course, when the air extraction hole 11 is a circular hole, the aperture can also be between 0.36 mm and 0.80 mm.

[0092] With such a design, controlling the hole area of the air extraction hole 11 between 0.00785 mm 2 and 0.785 mm 2 can achieve effective exhaust; at the same time, it can reduce the probability of glue overflow or imprint during the lamination process and improve the lamination quality.

[0093] According to some embodiments of the present application, optionally, please refer to Figure 1 , the extrusion rollers 20 include more than two, and all the extrusion rollers 20 are spaced apart from each other on the outer periphery of the support roller 10 along the axis.

[0094] By arranging more than two extrusion rollers 20 at intervals on the outer periphery of the support roller 10, the same part on the composite current collector can pass through different extrusion rollers 20 in sequence, realizing multi-stage lamination and strengthening the bonding between the conductive layer 300 and the substrate layer 200. At the same time, when passing through different extrusion rollers 20, the extrusion force between the conductive layer 300 and the substrate layer 200 by each extrusion roller 20 can be the same or different. For example: as the same part on the conductive layer 300 and the substrate layer 200 passes through different extrusion rollers 20 in sequence, the pressure it receives from the extrusion roller 20 gradually increases, etc.

[0095] Optionally, on the same support roller 10, the number of extrusion rollers 20 is not limited to only Figure 1 the 3 shown in, and can also be other numbers, such as: 2, 4, 5 or more.

[0096] For ease of understanding, three squeezing rollers 20 can be taken as an example for illustration. During the lamination process, the conductive layer 300 and the substrate layer 200 pass between three squeezing rollers 20 and the supporting roller 10 in sequence. Among them, the pressure applied by the first squeezing roller 20 can be controlled between 5 tons and 30 tons, the pressure applied by the second squeezing roller 20 can be controlled between 30 tons and 40 tons, and the pressure applied by the second squeezing roller 20 can be controlled between 40 tons and 50 tons. In this way, the lamination force between the conductive layer 300 and the substrate layer 200 is gradually increased, so that the gas is gradually discharged; the substrate layer 200 will not be wrinkled; and through three-stage squeezing, the conductive layer 300 and the substrate layer 200 are more effectively laminated, and the gas is more effectively discharged from the interface.

[0097] In addition, each squeezing roller 20 can be configured to have a structure that can be independently laminated or sprung open, which is convenient for debugging when the composite current collector is running the tape. For example: each squeezing roller 20 is fixed by adjusting bolts. When it is necessary to spring open, the adjusting bolts are loosened so that the squeezing roller 20 can move away from the supporting roller 10; or, each squeezing roller 20 is equipped with a device such as a cylinder, an electric cylinder, or a hydraulic cylinder.

[0098] With such a design, two or more squeezing rollers 20 are introduced to squeeze the same part of the conductive layer 300 and the substrate layer 200 multiple times, strengthening the lamination effect and making the conductive layer 300 and the substrate layer 200 closely combined; at the same time, the exhaust effect is also strengthened, reducing the probability of the conductive layer 300 peeling off.

[0099] According to some embodiments of the present application, optionally, please refer to Figure 1 , a lamination path 13 for the laminated conductive layer 300 and substrate layer 200 to pass through is formed between all the squeezing rollers 20 and the supporting roller 10. The central angle corresponding to the lamination path 13 on the supporting roller 10 is denoted as θ, where 180° ≤ θ < 360°.

[0100] The lamination path 13 refers to the path formed by the conductive layer 300 and the substrate layer 200 running the tape on the supporting roller 10. Since the conductive layer 300 and the substrate layer 200 are laminated on the supporting roller 10 under the action of the squeezing roller 20, therefore, the lamination path 13 can also be understood as the path formed along the roller surface of the supporting roller 10 from the lamination point of the first squeezing roller 20 on the supporting roller 10 to the lamination point of the last squeezing roller 20 on the supporting roller 10.

[0101] When both the squeezing roller 20 and the supporting roller 10 are configured as cylindrical structures, when determining the central angle of the lamination path 13, the axis of the first squeezing roller 20 can be connected to the axis of the supporting roller 10; then the axis of the last squeezing roller 20 is connected to the axis of the supporting roller 10, and the included angle between the two connecting lines is the central angle of the lamination path 13.

[0102] The central angle θ is greater than or equal to 180°, for example: the central angle θ can be but not limited to 180°, 190°, 200°, 210°, 225°, 270°, 300°, 330°, etc. Controlling the central angle θ to be greater than or equal to 180° can increase the wrap angle of the conductive layer 300 and the substrate layer 200 on the support roller 10, making the contact surface between the composite current collector and the support roller 10 larger, enhancing the pressing and exhaust effects; at the same time, if the support roller 10 can be heated, this can also increase the heating area of the composite current collector during the pressing process.

[0103] Of course, in some other embodiments, the central angle θ can also take values between 200 ° and 300°.

[0104] With such a design, controlling the central angle corresponding to the pressing path 13 to be greater than or equal to 180° can increase the wrap angle of the conductive layer 300 and the substrate layer 200 on the support roller 10, which is beneficial to improving the pressing and exhaust effects of the composite current collector.

[0105] According to some embodiments of the present application, optionally, please refer to Figure 3 , the area of the cross-section of at least one pressing roller 20 perpendicular to its own axis gradually increases first and then gradually decreases from one end of the pressing roller 20 to the other end.

[0106] It can be seen that at least one pressing roller 20 has a relatively large size in the middle part and relatively small sizes at both ends. In this way, during pressing, the pressure applied by the middle part is relatively large, which can drive the conductive layer 300 and the substrate layer 200 to have a tendency to expand towards both ends during the pressing process. At the same time, it is also beneficial to drive the bubbles in the glue to transfer towards both ends.

[0107] The number of the pressing rollers 20 with this structure can be one or more. When the number of the pressing rollers 20 with this structure is one, it can be arranged at a position that can press the same part of the composite current collector prior to the other pressing rollers 20, that is, the pressing roller 20 with this structure is located at the upstream end of the other pressing rollers 20 on the running path of the composite current collector.

[0108] Specifically, in some embodiments, the pressing roller 20 is configured as a cylindrical structure, and the roller surface diameter of the pressing roller 20 gradually decreases from the middle to both ends of the pressing roller 20.

[0109] To facilitate understanding of the cross-section of the pressing roller 20 perpendicular to its own axis, Figure 3 can be taken as an example, and the cross-section of the pressing roller 20 can be Figure 3 the parabolic region indicated by T in

[0110] With such a design, at least one pressing roller 20 is designed to have a larger size in the middle part and a smaller size at both ends, making the conductive layer 300 and the substrate layer 200 more flat during the pressing process; at the same time, it is also beneficial for the bubbles in the glue to transfer to both ends, improving the exhaust effect.

[0111] According to some embodiments of the present application, optionally, please refer to Figure 3 , in a plane passing through the axis of the pressing roller 20, the projection of the roller surface of the pressing roller 20 includes at least one contour line 21, and the angle between the contour line 21 and the axis of the pressing roller 20 is denoted as β, where 1° ≤ β ≤ 5°.

[0112] There can be multiple planes passing through the axis of the pressing roller 20. Since the roller surface of the pressing roller 20 is arranged around its own axis, therefore, to obtain the contour line 21 of the pressing roller 20, any one of the above-mentioned multiple planes can be taken as the projection plane. The pressing roller 20 in this embodiment has a structure with a larger middle size, so there will be at least one contour line 21 intersecting with the axis of the pressing roller 20 in the projection in this plane.

[0113] The angle β can take values between 1° and 5°, for example: it can be but not limited to 1°, 2°, 3°, 4°, 5°, etc. In some other embodiments, the angle β can also take values between 2° and 4°.

[0114] With such a design, the angle β is reasonably controlled between 1° and 5°, making the flattening effect of the conductive layer 300 and the substrate layer 200 better and improving the pressing quality.

[0115] According to some embodiments of the present application, optionally, the pressing mechanism 100 further includes a heating component (not shown), and the heating component is used to heat the roller surface of the supporting roller 10 and / or the pressing roller 20.

[0116] The heating component refers to a device that can generate heat, which can be an electric heating device, such as: electric heating wires, electric heating tubes, etc.; it can also be a heat transfer oil device, such as: passing the heated oil into the inside of the supporting roller 10 and / or the pressing roller 20 to heat the roller surface.

[0117] When the roller surface of the supporting roller 10 and / or the pressing roller 20 is heated, it will transfer heat to the surface of the conductive layer 300 and / or the substrate layer 200, softening the glue between the conductive layer 300 and the substrate layer 200, making the bonding between the two more firm. Of course, the heated bubbles are also easier to escape, enhancing the exhaust effect.

[0118] With such a design, the heating component is introduced to increase the surface temperature on the conductive layer 300 and / or the substrate layer 200, soften the glue, and improve the bonding performance; at the same time, it is also convenient for the bubbles in the glue to escape more easily, improving the exhaust effect.

[0119] According to some embodiments of the present application, optionally, please refer to Figure 1 , there are two or more supporting rollers 10 and pressing rollers 20. All the supporting rollers 10 are arranged side by side and at intervals, and each supporting roller 10 cooperates with at least one pressing roller 20.

[0120] The supporting rollers 10 being arranged side by side and at intervals means that the supporting rollers 10 are arranged at intervals with respect to each other, and the axes of the supporting rollers 10 are parallel or substantially parallel to each other. During the pressing process, the conductive layer 300 and the substrate layer 200 can be wound around the respective supporting rollers 10 in sequence, so that the conductive layer 300 and the substrate layer 200 are sequentially pressed on the respective supporting rollers 10. One pressing roller 20 can be configured on each supporting roller 10, or multiple pressing rollers 20 can be configured simultaneously.

[0121] The distribution of all the supporting rollers 10 can be arranged side by side and at intervals along the same straight line direction, or can be arranged side by side and at intervals along different straight line directions, as long as the axes of the supporting rollers 10 are parallel or substantially parallel to each other.

[0122] With such a design, two or more supporting rollers 10 are introduced, so that the conductive layer 300 and the substrate layer 200 are sequentially pressed on different supporting rollers 10, enhancing the bonding strength and improving the stability of the structure.

[0123] According to some embodiments of the present application, please refer to Figure 4 , the present application provides a composite current collector manufacturing device, including the pressing mechanism 100 as described in any one of the above.

[0124] For the above-mentioned composite current collector manufacturing device, by using the pressing mechanism 100 as described above, the conductive layer 300 and the substrate layer 200 are pressed while being sucked, accelerating the escape of gas between the conductive layer 300 and the substrate layer 200, reducing the bubbles between the conductive layer 300 and the substrate layer 200, improving the bonding force between the conductive layer and the substrate layer 200, reducing the peeling risk of the conductive layer 300, and being beneficial to improving the battery performance.

[0125] According to some embodiments of the present application, optionally, the composite current collector manufacturing device further includes a punching mechanism 30. On the running path of the substrate layer 200 or the conductive layer 300, the punching mechanism 30 is located at the upstream end of the pressing mechanism 100 and is used for punching the conductive layer 300 and / or the substrate layer 200.

[0126] The punching mechanism 30 refers to a device that can form a hole structure on the conductive layer 300 or the substrate layer 200, and it can be, but is not limited to, a laser punching device, a mechanical drill, etc.

[0127] The punching mechanism 30 is located at the upstream end of the extrusion mechanism 100. It can be understood that the conductive layer 300 and the substrate layer 200 are first punched by the punching mechanism 30; after punching, extrusion is carried out on the extrusion mechanism 100. The reason for setting the punching mechanism 30 at the upstream end of the extrusion mechanism 100 is that there are holes in the conductive layer 300 and / or the substrate layer 200 during lamination, so that gas can be discharged from the holes during lamination, enhancing the exhaust effect.

[0128] During the punching process, the holes in the conductive layer 300 or the substrate layer 200 can be determined according to the actual product. For example, the diameter size of the holes can be controlled within 50 μm to 500 μm. At the same time, the distance between the holes can be 5 mm to 50 mm.

[0129] With such a design, through the punching mechanism 30, holes are formed in the conductive layer 300 and / or the substrate layer 200, facilitating the escape of gas from the holes during lamination, further improving the exhaust effect, and thus making the combination between the conductive layer 300 and the substrate layer 200 more stable.

[0130] According to some embodiments of the present application, optionally, please refer to Figure 4 , the composite current collector preparation device further includes a gluing mechanism 40 on the running path of the substrate layer 200 or the conductive layer 300. The gluing mechanism 40 is located at the upstream end of the extrusion mechanism 100 and is used for gluing the conductive layer 300 and / or the substrate layer 200.

[0131] The gluing mechanism 40 refers to a device for coating glue on the conductive layer 300 and / or the substrate layer 200. The gluing mechanism 40 can be arranged on the running path of the substrate layer 200 or on the running path of the conductive layer 300; of course, the gluing mechanism 40 can be respectively arranged on the running paths of the substrate layer 200 and the conductive layer 300.

[0132] The gluing mechanism 40 is located at the upstream end of the extrusion mechanism 100. The purpose is that the conductive layer 300 and / or the substrate layer 200 are first glued by the gluing mechanism 40; after gluing, they then enter the extrusion mechanism 100. When entering the extrusion mechanism 100, the surfaces of the conductive layer 300 and / or the substrate layer 200 coated with glue are mutually adhered, so that the supporting roller 10 and the extrusion roller 20 respectively contact the uncoated surfaces.

[0133] There are various options for the glue - applying mechanism 40, such as, but not limited to, an intaglio coating mechanism. To reduce the air bubbles in the glue, a stirring device with an air - extraction function can be set. When stirring the glue, the air pressure in the stirring device can be controlled within 10000 Pa - 50000 Pa, such as 10000 Pa, 20000 Pa, 30000 Pa, 40000 Pa, 50000 Pa, etc. Meanwhile, when applying glue, the thickness of the glue can be controlled within 0.5μm - 5μm, such as 0.5μm, 1μm, 2μm, 3μm, 4μm, 5μm, etc.

[0134] With such a design, through the glue - applying mechanism 40, glue is stably applied to the conductive layer 300 and / or the substrate layer 200, so that the conductive layer 300 and the substrate layer 200 are stably adhered.

[0135] According to some embodiments of the present application, optionally, please refer to Figure 4 , the composite current - collector preparation device further includes a surface - treatment mechanism 60. The surface - treatment mechanism 60 is located at the upstream end of the glue - applying mechanism 40 and is used to improve the surface energy of the conductive layer 300 and / or the substrate layer 200.

[0136] The surface - treatment mechanism 60 refers to a device that improves the surface energy of the conductive layer 300 and / or the substrate layer 200, making it easier for the glue to adhere to the conductive layer 300 or the substrate layer 200. Surface energy refers to the non - volume work that must be done on a substance to reversibly increase the surface area of a system under constant temperature, constant pressure, and constant composition, which can increase the adhesion force to the glue. For example, the surface tension, wettability, etc. of the surface of the conductive layer 300 or the substrate layer 200.

[0137] Among them, the surface - treatment mechanism 60 can be, but not limited to, a corona roller, a pit - etching device, etc. When the surface - treatment mechanism 60 is a corona roller, air can be ionized, and under the action of an electric field, charged ions bombard the surface of the film layer to change the surface energy of the surface of the conductive layer 300 or the substrate layer 200.

[0138] With such a design, through the surface - treatment mechanism 60, the surface energy of the conductive layer 300 and / or the substrate layer 200 is improved, the adhesion to the glue is enhanced, so that the conductive layer 300 and the substrate layer 200 are stably combined, and the stability of the structure is improved.

[0139] According to some embodiments of the present application, optionally, please refer to Figure 4 , the composite current - collector preparation device further includes a baking mechanism 50. The baking mechanism 50 is located at the downstream end of the glue - applying mechanism 40 and is used to dry the conductive layer 300 and / or the substrate layer 200 after glue - application.

[0140] The baking mechanism 50 refers to a device that bakes the glue to eliminate some solvents in the glue. During the drying process, at least part of the solvent in the glue is volatilized, reducing the bubbles caused by solvent residues. At the same time, the glue is in a softened state, enabling stable bonding between the conductive layer 300 and the substrate layer 200.

[0141] The baking mechanism 50 can have various designs. For example, air nozzles can be provided in the baking mechanism 50 to blow out hot air. Among them, the baking temperature of the baking mechanism 50 can be 80°C to 150°C. For example, it can be, but is not limited to, 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc. At the same time, the blowing speed is 0.5m 3 / min to 5m 3 / min. For example, 0.5m 3 / min, 1m 3 / min, 2m 3 / min, 3m 3 / min, 4m 3 / min, 5m 3 / min, etc., and the blowing time can be 2S to 10S. For example, 2S, 3S, 4S, 5S, 6S, 7S, 8S, 9S, 10S, etc. It should be noted that the blowing time can be understood as follows: Since the composite current collector is continuously conveyed, the blowing time is the time acting on a certain part of the conductive layer 300 and / or the substrate layer 200; it can also be understood that the air blown by the air nozzle will form a certain area range, and the time for a certain part of the conductive layer 300 and / or the substrate layer 200 to pass through this area range is the blowing time.

[0142] With such a design, the baking mechanism 50 is introduced to accelerate the volatilization of the solvent in the glue, soften the glue, improve the bonding performance, and thus improve the adhesion between the conductive layer 300 and the substrate layer 200.

[0143] According to some embodiments of the present application, optionally, please refer to Figure 4 , the composite current collector manufacturing device further includes a passivation mechanism 70, and the passivation mechanism 70 is used to passivate at least one surface of the conductive layer 300.

[0144] The passivation mechanism 70 refers to a device that can form a passivation layer on the surface of the conductive layer 300. There are various choices for the passivation agent used, such as: the passivation agent includes one or more of organic phosphates, chromates, dichromates, Al2O3, SiO2, and Si3N4. Among them, the organic phosphates include one or more of hydroxyethylidene diphosphonic acid, diethylenetriamine pentamethylenephosphonic acid, triethylenetetramine hexamethylenephosphonic acid, and ethylenediamine tetramethylenephosphonic acid. The chromates include one or more of sodium chromate, potassium chromate, magnesium chromate, and silver chromate. The dichromates include one or more of ammonium dichromate, potassium dichromate, sodium dichromate, and magnesium dichromate.

[0145] When a passivation layer is formed on the surface of the conductive layer 300, the corrosion resistance of the conductive layer 300 under long-term cyclic storage of the electrolyte can be improved, thereby further enhancing the peel strength and reliability between the substrate layer 200 and the conductive layer 300, and further reducing the peeling risk of the composite current collector under long-term immersion in the electrolyte.

[0146] At the same time, when the passivation mechanism 70 passivates one surface of the conductive layer 300 facing the substrate layer 200, the adhesion of the conductive layer 300 to the glue can also be increased, improving the bonding strength.

[0147] In addition, when the passivation mechanism 70 and the surface treatment mechanism 60 (such as a corona roll) are simultaneously introduced on the running path of the conductive layer 300, the passivation mechanism 70 can be located at the downstream end of the surface treatment mechanism 60, so that after surface treatment, the passivation layer can better infiltrate the conductive layer 300.

[0148] With such a design, by introducing the passivation layer, the corrosion resistance of the conductive layer 300 under long-term cyclic storage of the electrolyte can be improved, and the peeling risk of the composite current collector under long-term immersion in the electrolyte can be reduced; at the same time, the adhesion of the conductive layer 300 to the glue is also improved, further enhancing the structural stability.

[0149] According to some embodiments of the present application, optionally, please refer to Figure 4 , the composite current collector manufacturing apparatus further includes a first unwinding mechanism 80 and a second unwinding mechanism 81, and the first unwinding mechanism 80 and the second unwinding mechanism 81 are respectively used to release the conductive layer 300 and the substrate layer 200 correspondingly.

[0150] The first unwinding mechanism 80 is used to release the conductive layer 300, and the second unwinding mechanism 81 is used to release the substrate layer 200. The structures of both can be designed into cylindrical or disk-shaped structures, etc. The number of the first unwinding mechanisms 80 can be one or more. When the number of the first unwinding mechanisms 80 is more than one, two of the first unwinding mechanisms 80 are used to release the conductive layer 300 onto two surfaces of the substrate layer 200 respectively, so that the composite current collector can be formed in one step.

[0151] In addition, when two of the first unwinding mechanisms 80 release the conductive layer 300 onto the two surfaces of the substrate layer 200 respectively, the two first unwinding mechanisms 80 can be located on opposite sides of the running path of the substrate layer 200, and the two first unwinding mechanisms 80 can release the conductive layer 300 onto the same support roller 10. Reference can be made to Figure 5 ; or they can be released onto different support rollers 10. Reference can be made to Figure 6 . For example: Please refer to Figure 6 , where the conductive layer 300 released by the first unwinding mechanism 80 and the substrate layer 200 released by the second unwinding mechanism 81 enter between one of the support rollers 10 and the pressing roller 20, so that one surface of the substrate layer 200 is bonded with a layer of the conductive layer 300. Then, the conductive layer 300 released by the other first unwinding mechanism 80 and the substrate layer 200 bonded with the conductive layer 300 enter between the other support roller 10 and the pressing roller 20.

[0152] With such a design, the introduction of the first unwinding mechanism 80 and the second unwinding mechanism 81 enables the continuous and stable preparation of the composite current collector.

[0153] According to some embodiments of the present application, optionally, please refer to Figure 4 , the composite current collector preparation device further includes a winding mechanism 90, and the winding mechanism 90 is used to wind the pressed conductive layer 300 and substrate layer 200 output by the pressing mechanism 100.

[0154] The winding mechanism 90 refers to winding the substrate layer 200 bonded and pressed with the conductive layer 300, and it can be designed into a cylindrical or disc-shaped structure.

[0155] With such a design, through the winding mechanism 90, it is convenient to store the composite current collector.

[0156] According to some embodiments of the present application, please refer to Figure 7 , the present application provides a method for preparing a composite current collector, and the method includes the following steps:

[0157] S100. Punch through holes on the surfaces of the substrate layer 200 and / or the conductive layer 300;

[0158] S200. Apply glue to the surfaces of the substrate layer 200 and / or the conductive layer 300;

[0159] S300. Superpose and bond the substrate layer 200 and the conductive layer 300;

[0160] S400. Extrude and evacuate the superposed substrate layer 200 and conductive layer 300.

[0161] The "and / or" in step S100 has no necessary association with the "and / or" in step S200. For example, in step S100, holes are drilled in the substrate layer 200. In step S200, glue can be applied to the substrate layer 200 or the conductive layer 300. In step S100, holes are drilled in the conductive layer 300. In step S200, glue can be applied to the substrate layer 200 or the conductive layer 300, etc.

[0162] Meanwhile, there can be multiple execution sequences between step S100 and step S200. For example, drilling can be done first and then gluing, or gluing can be done first and then drilling. In some specific embodiments, step S100 is executed first and then step S200.

[0163] Among them, through-holes are drilled on the surfaces of the substrate layer 200 and / or the conductive layer 300, so that through-holes can be formed on the substrate layer 200 and / or the conductive layer 300. In this way, air bubbles in the glue can escape from these holes during lamination. Regarding the size limitation of the holes, the hole design in the above embodiments can be referred to. At the same time, the material limitations of the substrate layer 200 and the conductive layer 300 can also be referred to the above embodiments and will not be elaborated here.

[0164] In step S300, the number of conductive layers 300 can be one or two. When the number of conductive layers 300 is two, the two conductive layers 300 are respectively bonded to the opposite two surfaces of the substrate layer 200 by glue. When the number of conductive layers 300 is one, after the conductive layer 300 on one surface is laminated, steps S100 to S400 can be repeatedly executed.

[0165] In step S400, the substrate layer 200 and the conductive layer 300 are extruded so that the substrate layer 200 and the conductive layer 300 are tightly bonded. During the extrusion process, air extraction can be carried out to drive the air bubbles in the glue between the substrate layer 200 and the conductive layer 300 to be discharged, reducing the probability of the conductive layer 300 peeling off. There are various ways to achieve air extraction. For example, the extrusion operation can be carried out in a negative pressure environment, or the extrusion roller 20 and the support roller 10 in the above embodiments can be used. Of course, the preparation method of this embodiment can completely adopt the composite current collector preparation device in any of the above embodiments.

[0166] With such a design, by adopting this preparation method, the conductive layer 300 and the substrate layer 200 are being extruded and suctioned at the same time, accelerating the escape of gas between the conductive layer 300 and the substrate layer 200, reducing the air bubbles between the conductive layer 300 and the substrate layer 200, improving the bonding force between the conductive layer and the substrate layer 200, reducing the peeling risk of the conductive layer 300, and being beneficial to improving the battery performance.

[0167] According to some embodiments of the present application, optionally, please refer toFigure 8 Step S400 of extruding and evacuating the laminated substrate layer 200 and the conductive layer 300 includes:

[0168] S410, passing the laminated substrate layer 200 and the conductive layer 300 between the support roller 10 and the extrusion roller 20;

[0169] S420, extruding and conveying the substrate layer 200 and the conductive layer 300 through the cooperation of the support roller 10 and the extrusion roller 20;

[0170] S430, evacuating the air extraction holes 11 on the roller surfaces of the support roller 10 and / or the extrusion roller 20.

[0171] The support roller 10 and the extrusion roller 20 respectively refer to the structures acting on the opposite sides of the composite current collector, and both can be in a cylindrical structure. Of course, the features of the support roller 10 and the extrusion roller 20 can refer to the support roller 10 and the extrusion roller 20 in any of the above embodiments, which will not be elaborated here.

[0172] With such a design, the support roller 10 and the extrusion roller 20 are introduced, so that during the pressing process, extrusion and suction are achieved simultaneously, accelerating the discharge of gas from the holes in the conductive layer 300 and / or the substrate layer 200, improving the exhaust effect, and enabling stable bonding between the conductive layer 300 and the substrate layer 200.

[0173] According to some embodiments of the present application, optionally, in the step of extruding and conveying the substrate layer 200 and the conductive layer 300 through the cooperation of the support roller 10 and the extrusion roller 20, the extrusion roller 20 includes more than two. The substrate layer 200 and the conductive layer 300 sequentially pass between each extrusion roller 20 and the support roller 10, and along the running direction of the substrate layer 200, the pressure applied by each extrusion roller 20 on the same support roller 10 gradually increases.

[0174] It can be seen that by arranging more than two extrusion rollers 20 at intervals on the outer periphery of the support roller 10, the same part of the composite current collector can sequentially pass through different extrusion rollers 20, realizing multi-stage pressing and strengthening the bonding between the conductive layer 300 and the substrate layer 200. At the same time, when passing through different extrusion rollers 20, the extrusion force between the conductive layer 300 and the substrate layer 200 by each extrusion roller 20 can be the same or different. For example, as the same part of the conductive layer 300 and the substrate layer 200 sequentially passes through different extrusion rollers 20, the pressure it receives from the extrusion roller 20 gradually increases, etc.

[0175] Optionally, on the same support roller 10, the number of extrusion rollers 20 is not limited to Figure 1 the three shown in

[0176] In addition, each extrusion roller 20 can be configured to be able to perform independent pressing or bouncing, which is convenient for debugging when the composite current collector is running the tape. For example: each extrusion roller 20 is fixed by adjusting bolts. When it is necessary to bounce, the adjusting bolts are loosened so that the extrusion roller 20 can move away from the support roller 10; or, each extrusion roller 20 is equipped with a device such as a cylinder, an electric cylinder, or a hydraulic cylinder.

[0177] With such a design, more than two extrusion rollers 20 are introduced to repeatedly extrude the same part of the conductive layer 300 and the substrate layer 200, strengthening the pressing effect and enabling the conductive layer 300 and the substrate layer 200 to be tightly combined; at the same time, the exhaust effect is also strengthened, reducing the probability of peeling of the conductive layer 300.

[0178] According to some embodiments of the present application, optionally, please refer to Figure 9 , after the step S200 of applying glue to the surface of the substrate layer 200 and / or the conductive layer 300, the following is further included:

[0179] S500. Bake the substrate layer 200 and / or the conductive layer 300 coated with glue.

[0180] The purpose of baking is to volatilize the solvent in the glue, reducing the probability of subsequent bubble generation due to solvent residue; at the same time, the glue can also be softened to improve the bonding performance.

[0181] With such a design, introducing the baking process can reduce the generation of bubbles; at the same time, it is also beneficial to the bonding performance of the glue, enabling the conductive layer 300 and the substrate layer 200 to be tightly connected.

[0182] According to some embodiments of the present application, optionally, the baking parameters include at least one of the following: the blowing speed on the surface of the substrate layer 200 and / or the conductive layer 300 is 0.5m 3 / min ~ 5m 3 / min; the blowing time on the surface of the substrate layer 200 and / or the conductive layer 300 is 2S ~ 10S; the baking temperature is 80°C ~ 150°C. It should be noted that the blowing time can be understood as: since the composite current collector is continuously conveyed, the blowing time is the time acting on a certain part of the conductive layer 300 and / or the substrate layer 200; it can also be understood that the blowing of the air nozzle will form a certain area range, and the time taken for a certain part of the conductive layer 300 and / or the substrate layer 200 to pass through this area range is the blowing time.

[0183] When controlling the baking temperature, it should not be too high or too low. If it is too low, the glue cannot be softened and the solvent in the glue cannot be eliminated; if it is too high, the glue will be coked and even the structure of the substrate layer 200 will be damaged. Therefore, the baking temperature should be controlled to be greater than the softening temperature of the glue and less than the melting point of the substrate layer 200.

[0184] For this reason, the baking temperature can be 80°C to 150°C. For example, it can be but is not limited to 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, etc.

[0185] At the same time, blowing air can accelerate the volatilization of the solvent in the glue, and the blowing speed is 0.5 m 3 / min to 5 m 3 / min. For example, 0.5 m 3 / min, 1 m 3 / min, 2 m 3 / min, 3 m 3 / min, 4 m 3 / min, 5 m 3 / min, etc., and the blowing time can be 2 s to 10 s. For example, 2 s, 3 s, 4 s, 5 s, 6 s, 7 s, 8 s, 9 s, 10 s, etc.

[0186] In this way, by reasonably controlling the baking temperature, blowing speed and blowing time, the residual solvent in the glue can be further reduced, and the bonding performance of the glue can be improved, thereby improving the adhesion between the conductive layer 300 and the substrate layer 200.

[0187] According to some embodiments of the present application, optionally, please refer to Figure 9 , before the step S200 of applying glue to the surface of the substrate layer 200 and / or the conductive layer 300, it further includes:

[0188] S600. Corona treatment is performed on the surface of the substrate layer 200 and / or the conductive layer 300.

[0189] Corona refers to ionizing air. Under the action of an electric field, charged ions bombard the surface of the film layer to improve the surface energy of the conductive layer 300 or the substrate layer 200 and increase the wettability of the glue on the conductive layer 300 or the substrate layer 200. At the same time, corona treatment can also clean the surface of the conductive layer 300 or the substrate layer 200. Among them, in corona, equipment such as a corona roller, a discharge electrode and a power supply can be used.

[0190] In addition, before performing step S300, the conductive layer 300 can also be passivated. For example, a passivating agent such as one or more of organic phosphates, chromates, dichromates, Al2O3, SiO2, and Si3N4 is used to passivate the conductive layer 300, so that a passivation layer is formed on its surface. When a passivation layer is formed on the surface of the conductive layer 300, the corrosion resistance of the conductive layer 300 under long-term cyclic storage of the electrolyte can be improved, thereby further improving the peel strength and its reliability between the substrate layer 200 and the conductive layer 300, and further reducing the peeling risk of the composite current collector under long-term immersion in the electrolyte. Of course, the passivation treatment can be performed in step S600. In this way, through corona, the wettability of the surface of the conductive layer 300 is changed, making it easier for the passivation layer to adhere to the surface of the conductive layer 300.

[0191] With such a design, the corona step is introduced to improve the corrosion resistance of the conductive layer 300 under long-term cyclic storage of the electrolyte and reduce the peeling risk of the composite current collector under long-term immersion in the electrolyte. At the same time, the adhesion of the conductive layer 300 to the glue is also improved, further enhancing the structural stability.

[0192] According to some embodiments of the present application, the present application provides a battery production system, which includes the composite current collector preparation device according to any one of the above.

[0193] According to some embodiments of the present application, please refer to Figures 1 to 9 , the present application provides a composite current collector preparation device, which includes a first unwinding mechanism 80, a second unwinding mechanism 81, a pressing mechanism 100, and a winding mechanism 90. The pressing mechanism 100 includes a support roller 10 and a plurality of pressing rollers 20 arranged at intervals along the circumferential direction of the support roller 10. The first unwinding mechanism 80 releases the conductive layer 300 between the support roller 10 and the pressing rollers 20, and the second unwinding mechanism 81 releases the substrate layer 200 between the support roller 10 and the pressing rollers 20, and makes the substrate layer 200 and the conductive layer 300 overlap. Along the running path of the conductive layer 300, a punching mechanism 30, a surface treatment mechanism 60 (such as a corona module), and a passivation mechanism 70 are sequentially arranged. Along the running path of the substrate layer 200, a punching mechanism 30, a surface treatment mechanism 60 (such as a corona module), a gluing mechanism 40, and a baking mechanism 50 are sequentially arranged.

[0194] Hereinafter, embodiments of the present application will be described. The embodiments described below are exemplary and are only used to explain the present application, and should not be construed as a limitation to the present application. For those not specified in the embodiments in terms of techniques or conditions, the techniques or conditions described in the literature in the art or according to the product specifications are followed. For the reagents or instruments not specified in the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0195] Example 1

[0196] The base material layer 200 and the conductive layer 300 are threaded

[0197] The conductive layer 300 uses an aluminum foil with a thickness of 10 μm and a width of 600 mm; the base material layer 200 uses PET (polyethylene glycol terephthalate, translated as polyethylene terephthalate) with a thickness of 6 μm and a width of 600 mm; the glue uses modified polypropylene. The above conductive layer 300 and the base material layer 200 are laminated and successively threaded between the extrusion roller 20 and the support roller 10.

[0198] Punching treatment

[0199] A laser puncher is used at the upstream end of the extrusion mechanism 100 to perform on-line punching on the conductive layer 300 and the base material layer 200 respectively. The aperture on the conductive layer 300 and the base material layer 200 is 200 μm, and the hole pitch is 10 mm.

[0200] Corona treatment

[0201] The punched conductive layer 300 and the base material layer 200 are subjected to on-line corona treatment, where the corona voltage is 15 kV.

[0202] Gluing treatment

[0203] The glue is coated on one surface of the base material layer 200 on-line using an intaglio coating roller, and the thickness of the glue is 1 μm.

[0204] Baking treatment

[0205] The glued base material layer 200 is baked on-line by blowing air, the baking temperature is 100 °C, the blowing speed is 1 m 3 / min, and the blowing time at any part of the surface of the base material layer 200 is controlled to be 5 s.

[0206] Passivation treatment

[0207] Sodium chromate, a passivation material, is coated on the surface of the metal aluminum foil and dried at 90 °C.

[0208] Extrusion mechanism 100 and extrusion treatment

[0209] The extrusion mechanism 100 includes two juxtaposed and spaced support rollers 10, and three extrusion rollers 20 spaced at intervals on the outer periphery of each support roller 10. The diameter of the support roller 10 is 600 mm, the center distance between the two support rollers 10 is 1800 mm, and the central angle of any two adjacent extrusion rollers 20 on the support roller 10 is 45°. A plurality of air extraction holes 11 are formed on the roller surface of the support roller 10, the aperture of the air extraction holes 11 is 0.1 mm, and the distance between the air extraction holes 11 is 5 mm. A through-air flow channel 12 communicating with each air extraction hole 11 is formed at the axis of each support roller 10. By extracting air from the through-air flow channel 12, the air pressure in the through-air flow channel 12 is 5×10 4 Pa.

[0210] On each support roller 10, the applied pressure on the first extrusion roller 20 in the tape running direction is controlled to be 30 tons, the applied pressure on the second extrusion roller 20 is controlled to be 40 tons, and the applied pressure on the third extrusion roller 20 is controlled to be 50 tons. At the same time, the diameter of the first extrusion roller 20 gradually decreases from the middle to both ends, the inclination angle is 3°, and the diameter in the middle of the first extrusion roller 20 is 25 mm. The diameters of the remaining two extrusion rollers 20 are 25 mm.

[0211] After the above treatment, a substrate layer 200 with a conductive layer 300 adhered to one surface thereof is obtained; then, the substrate layer 200 with a conductive layer 300 and the conductive layer 300 are re-passed between the support roller 10 and the extrusion roller 20, and the above punching treatment, corona treatment, gluing treatment, baking treatment and passivation treatment are repeated to obtain a composite current collector.

[0212] Example 2

[0213] Basically the same as Example 1, the difference is only that: the diameter of the air extraction holes 11 on the support roller 10 is 0.5 mm.

[0214] Example 3

[0215] Basically the same as Example 1, the difference is only that: the diameter of the air extraction holes 11 on the support roller 10 is 1 mm.

[0216] Example 4

[0217] Basically the same as Example 2, the difference is only that: the hole spacing of the air extraction holes 11 on the support roller 10 is 20 mm.

[0218] Example 5

[0219] Basically the same as Example 2, the difference is only that: the hole spacing of the air extraction holes 11 on the support roller 10 is 50 mm.

[0220] Example 6

[0221] It is basically the same as Example 4, except that: the number of extrusion rollers 20 on each support roller 10 is 1, and the pressure applied by the extrusion roller 20 is 50 tons.

[0222] Example 7

[0223] It is basically the same as Example 4, except that: the number of extrusion rollers 20 on each support roller 10 is 4, and the pressure applied by the first extrusion roller 20 in the running direction of the tape is 20 tons, the pressure applied by the second extrusion roller 20 is 30 tons, the pressure applied by the third extrusion roller 20 is 40 tons, and the pressure applied by the fourth extrusion roller 20 is 50 tons.

[0224] Example 8

[0225] It is basically the same as Example 1, except that: during the preparation process, the conductive layer 300 is not subjected to corona treatment.

[0226] Example 9

[0227] It is basically the same as Example 1, except that: during the preparation process, the base material layer 200 is not subjected to corona treatment.

[0228] Example 10

[0229] It is basically the same as Example 1, except that: no air extraction is performed in the first support roller 10 in the running direction of the tape.

[0230] Example 11

[0231] It is basically the same as Example 1, except that: no air extraction is performed in the second support roller 10 in the running direction of the tape.

[0232] Comparative Example 1

[0233] It is basically the same as Example 1, except that: the diameter of the air extraction holes 11 on each support roller 10 is 0.05 mm.

[0234] Comparative Example 2

[0235] It is basically the same as Example 2, except that: the hole pitch of the air extraction holes 11 on each support roller 10 is 60 mm.

[0236] Comparative Example 3

[0237] It is basically the same as Example 1, except that: during the preparation process, neither the conductive layer 300 nor the base material layer 200 is subjected to corona treatment.

[0238] Comparative Example 4

[0239] It is basically the same as Example 1, except that: no air extraction is performed in both support rollers 10.

[0240] Comparative Example 5

[0241] It is basically the same as Comparative Example 4, except that: during the preparation process, neither the conductive layer 300 nor the substrate layer 200 is subjected to corona treatment.

[0242] Comparative Example 6

[0243] It is basically the same as Comparative Example 5, except that: the number of extrusion rollers 20 on each support roller 10 is 1, and the pressure applied by the extrusion roller 20 is 50 tons.

[0244] Comparative Example 7

[0245] It is basically the same as Comparative Example 6, except that: the conductive layer 300 and the substrate layer 200 are not perforated, and no air extraction holes 11 are provided on the roller surfaces of each support roller 10.

[0246] In each embodiment and each comparative example, the parameters used are shown in Table 1.

[0247] Table 1

[0248]

[0249] The composite current collectors prepared in each embodiment and each comparative example are successively subjected to a conductive layer 300 peeling test, an adhesion test, an immersion adhesion test, and a 60 °C cycle number test. The specific results can be referred to in Table 2.

[0250] Conductive layer 300 peeling test

[0251] Cut the sample into a width of ≥20 mm and a length greater than 100 mm, fix it on a steel plate with double-sided tape, attach a 20 mm wide tape (adhesive force 200 N / m) to the surface of the sample, conduct a peeling test, perform a 180 ° peeling test at a speed of 500 mm / min, and the peeling area is 2000 mm 2 (peeling distance 100 mm). At the same time, observe the metal chips remaining on the tape under a microscope, read the area of the metal chips, and sum up the areas of all the dropped metal chips to obtain the peeling area of the conductive layer of each current collector.

[0252] Adhesion test

[0253] After the sample is non-corona surface-bonded with an ethylene-acrylic acid copolymer (EAA) film, a 12-μm-thick PET is then covered on the EAA film, and it is placed on a heat sealer and bonded at a temperature of 120 °C and a pressure of 0.2 MPa. The bonded sample is cut into samples with a length of 100 mm and a width of 20 mm, and the non-bonded surface of the conductive layer is attached to a steel plate with 3M double-sided tape; the sample is clamped on the fixture of a tensile machine with a spacing of 50 mm and a speed of 300 mm / min for a 180-degree peel test, and the peel force is read and converted into the unit of N / m. There are 5 parallel samples, and finally the average peel force is taken; the average peel force = the sum of the peel forces of 5 test samples / 5, and this is the bonding force.

[0254] Immersion Bonding Force Test

[0255] Cut the sample into strips with a size of 3 cm × 10 cm, inject 20 mL of electrolyte, seal it with a Pocket bag, and test the bonding force after soaking at 60 °C for 7 days.

[0256] 60 °C Cycle Number Test

[0257] The fresh battery cell is cycled at a 1C charge rate and a 1C discharge rate under the condition of 60 °C until the capacity decays to 80% of the initial capacity, and the corresponding cycle number is recorded at this time, which is the cycle performance of the corresponding battery.

[0258] Table 2

[0259]

[0260] Comparing Examples 1-11 with Comparative Example 7, it can be seen that the bonding force, the peeling area of the conductive layer, and the immersion bonding force of the composite current collectors in each example are all better than those of Comparative Example 7. At the same time, the cycle number of the battery at 60 °C is better than that of Comparative Example 7, indicating that compared with the composite current collectors of the conventional process, the process composite current collectors of the present application are beneficial to improving the bonding force and the cycle performance of the battery.

[0261] Comparing Examples 1, 10-11, Comparative Example 1 and Comparative Example 4, it can be known that by using the air extraction method to extrude the composite current collector, the bonding force, the peeling area of the conductive layer, and the immersion bonding force of the obtained composite current collector are all better than those of Comparative Example 4; at the same time, the air extraction method is adopted during both extrusion processes, which can better improve the mechanical properties and cycle performance of the composite current collector.

[0262] From Examples 1-3 and Comparative Example 1, it can be seen that when the aperture of the air extraction hole 11 is designed at 0.1 mm, 0.5 mm, and 1 mm, the peeling area of the conductive layer 300 of the composite current collector can be controlled at 0.1 mm 2 or 0.2 mm 2etc., the adhesive force of the current collector is above 293 N / m, the immersion adhesive force is 285 N / m, and the number of cycles is above 506. At the same time, the performance of the above composite current collectors is better than that of the composite current collector obtained when the pore diameter of the air extraction hole 11 is 0.05 mm.

[0263] From Example 2, Examples 4-5 and Comparative Example 2, it can be seen that compared with Comparative Example 2, when the distance between the air extraction holes 11 is controlled at 5 mm, 20 mm, and 50 mm, the performance of the obtained composite current collector is relatively good. For example, the peeling area of the conductive layer 300 can be controlled to be no higher than 0.3 mm 2 , the adhesive force of the current collector is above 289 N / m, the immersion adhesive force is 280 N / m, and the number of cycles is above 504.

[0264] From Examples 4, 6-7, it can be seen that by arranging two or more pressing rollers 20 on the same support roller 10 to achieve multi-stage pressing, the mechanical properties and cycling properties of the obtained composite current collector will be relatively better.

[0265] Comparing Examples 1, Examples 8-9 and Comparative Example 3, it can be seen that both the base material layer 200 and the conductive layer 300 are subjected to corona treatment, which is beneficial to improving the mechanical properties and cycling properties of the composite current collector. When comparing Comparative Example 3 and Comparative Examples 5-6, it can be seen that the degree of improvement in the performance of the composite current collector by air extraction is better than that by corona treatment.

[0266] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0267] The above-described embodiments only represent several implementation manners of the present application. The description is relatively specific and detailed, but it cannot be understood as a limitation on the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. An extrusion mechanism, characterized in that, The extrusion mechanism includes: a support roller (10); an extrusion roller (20) for extruding the mutually bonded conductive layer (300) and the substrate layer (200) between the support roller (10); wherein, in the support roller (10) and the extrusion roller (20), at least one is provided with air extraction holes (11) for communicating with a suction device on the roller surface arranged circumferentially along its own axis.

2. The extrusion mechanism according to claim 1, wherein The support roller (10) and / or the extrusion roller (20) having the air extraction holes (11) is provided with an air flow channel (12) extending in the direction of its own axis, and the air flow channel (12) communicates with the corresponding air extraction holes (11).

3. The extrusion mechanism according to claim 1, wherein In the support roller (10) or the extrusion roller (20), there are more than two air extraction holes (11), and at least some of the air extraction holes (11) are spaced apart.

4. The extrusion mechanism according to claim 3, characterized in that, In the spaced-apart air extraction holes (11), the distance between two adjacent air extraction holes (11) is denoted as L, where 5 mm ≤ L ≤ 50 mm; Optionally, the condition that the distance L also satisfies is: 10 mm ≤ L ≤ 30 mm.

5. The extrusion mechanism according to claim 1, characterized in that In the support roller (10) or the extrusion roller (20), there are more than two air extraction holes (11), and at least some of the air extraction holes (11) are spaced apart circumferentially around the corresponding axis.

6. The extrusion mechanism according to claim 1, wherein The hole area of the air extraction hole (11) on the roll surface of the support roll (10) or the extrusion roll (20) is denoted as S, where 0.00785 mm 2 ≤ S ≤ 0.785 mm 2 ; Optionally, the pore area S also satisfies the condition that: 0.1 mm 2 ≤ S ≤ 0.5 mm 2 ; Optionally, the air extraction holes (11) are configured as circular holes, and the diameter of the air extraction holes (11) is: 0.1 mm to 1 mm.

7. The extrusion mechanism according to any one of claims 1-6, characterized in that, There are more than two extrusion rollers (20), and all the extrusion rollers (20) are spaced apart circumferentially around the axis of the support roller (10).

8. The extrusion mechanism according to claim 7, characterized in that, A pressing path (13) is formed between all the extrusion rollers (20) and the support roller (10) for the laminated conductive layer (300) and the substrate layer (200) to pass through. The central angle corresponding to the pressing path (13) on the support roller (10) is denoted as θ, where 180° ≤ θ < 360°; Optionally, the condition that the central angle θ also satisfies is: 200° ≤ θ ≤ 300°.

9. The extrusion mechanism according to any one of claims 1-6, characterized in that, The cross-sectional area of at least one extrusion roller (20) in a plane perpendicular to its own axis gradually increases first and then gradually decreases from one end of the extrusion roller (20) to the other end.

10. The extrusion mechanism according to claim 9, wherein, In a plane passing through the axis of the extrusion roller (20), the projection of the roller surface of the extrusion roller (20) includes at least one contour line (21), and the angle between the contour line (21) and the axis of the extrusion roller (20) is denoted as β, where 1° ≤ β ≤ 5°; Optionally, the condition that the angle β also satisfies is: 2° ≤ β ≤ 4°.

11. The extrusion mechanism according to any one of claims 1-6, characterized in that, The extrusion mechanism further includes a heating component for heating the roller surfaces of the support roller (10) and / or the extrusion roller (20).

12. The extrusion mechanism according to any one of claims 1-6, characterized in that, Both the support roller (10) and the extrusion roller (20) include more than two, and all the support rollers (10) are arranged side by side and spaced apart, and each support roller (10) cooperates with at least one extrusion roller (20).

13. A compound current collector preparation device, characterized in that An extrusion mechanism according to any one of claims 1 - 12 is included.

14. The composite current collector manufacturing apparatus according to claim 13, wherein The composite current collector manufacturing device further includes a punching mechanism (30). On the tape running path of the base material layer (200) or the conductive layer (300), the punching mechanism (30) is located at the upstream end of the extrusion mechanism and is used to punch holes in the conductive layer (300) and / or the base material layer (200).

15. The composite current collector preparation device according to claim 13, characterized in that, The composite current collector manufacturing device further includes a gluing mechanism (40). On the tape running path of the base material layer (200) or the conductive layer (300), the gluing mechanism (40) is located at the upstream end of the extrusion mechanism and is used to apply glue to the conductive layer (300) and / or the base material layer (200).

16. The composite current collector preparation device according to claim 15, characterized in that The composite current collector manufacturing device further includes a surface treatment mechanism (60). The surface treatment mechanism (60) is located at the upstream end of the gluing mechanism (40) and is used to improve the surface energy of the conductive layer (300) and / or the base material layer (200); and / or, The composite current collector manufacturing device further includes a baking mechanism (50). The baking mechanism (50) is located at the downstream end of the gluing mechanism (40) and is used to dry the conductive layer (300) and / or the base material layer (200) after glue application.

17. The composite current collector preparation device according to any one of claims 13-16, characterized in that The composite current collector manufacturing device further includes a passivation mechanism (70). The passivation mechanism (70) is used to passivate at least one surface of the conductive layer (300).

18. The composite current collector manufacturing apparatus according to any one of claims 13-16, characterized in that The composite current collector manufacturing device further includes a first unwinding mechanism (80) and a second unwinding mechanism (81). The first unwinding mechanism (80) and the second unwinding mechanism (81) are respectively used to release the conductive layer (300) and the base material layer (200) correspondingly; and / or, The composite current collector manufacturing device further includes a winding mechanism (90). The winding mechanism (90) is used to wind the pressed conductive layer (300) and the base material layer (200) output by the extrusion mechanism.

19. A method for preparing a composite current collector, characterized in that, The method includes the following steps: Perforate the surface of the base material layer (200) and / or the conductive layer (300) through holes. Apply glue to the surface of the base material layer (200) and / or the conductive layer (300). Superpose and bond the base material layer (200) and the conductive layer (300). Extrude and evacuate the superposed base material layer (200) and conductive layer (300).

20. The method for preparing a composite current collector according to claim 19, wherein The step of extruding and evacuating the superposed base material layer (200) and conductive layer (300) includes: Pass the superposed base material layer (200) and conductive layer (300) between the support roller (10) and the extrusion roller (20). Cooperate the support roller (10) and the extrusion roller (20) to extrude and convey the base material layer (200) and the conductive layer (300). Evacuate the air extraction holes (11) on the roller surfaces of the support roller (10) and / or the extrusion roller (20).

21. The method for preparing a composite current collector according to claim 20, wherein In the step of extruding and conveying the base material layer (200) and the conductive layer (300) through the cooperation of the supporting roller (10) and the extrusion roller (20), there are more than two extrusion rollers (20). The base material layer (200) and the conductive layer (300) pass between each extrusion roller (20) and the supporting roller (10) in sequence, and along the running direction of the base material layer (200), the pressure applied by each extrusion roller (20) on the same supporting roller (10) gradually increases.

22. The method for preparing a composite current collector according to claim 19, wherein, After the step of applying glue to the surface of the base material layer (200) and / or the conductive layer (300), it further includes: Baking the base material layer (200) and / or the conductive layer (300) coated with glue.

23. The method for preparing a composite current collector according to claim 22, wherein, The parameters of the baking include at least one of the following: The blowing speed of the surface of the substrate layer (200) and / or the conductive layer (300) is 0.5 m 3 / min to 5 m 3 / min; The blowing time on the surface of the base material layer (200) and / or the conductive layer (300) is 2S - 10S; The baking temperature is 80°C - 150°C.

24. The method for preparing a composite current collector according to any one of claims 19-23, characterized in that Before the step of applying glue to the surface of the base material layer (200) and / or the conductive layer (300), it further includes: Corona treating the surface of the base material layer (200) and / or the conductive layer (300).

25. A battery production system, characterized in that, The battery production system includes the composite current collector preparation device according to any one of claims 13 - 18.

Images