Composite current collector and preparation method thereof, electrode plate and battery

Abstract

The invention discloses a composite current collector and a preparation method thereof, an electrode plate and a battery. The composite current collector comprises a polymer layer and metal layers stacked on the two sides of the polymer layer in the thickness direction. Wherein the composite current collector further comprises a conductive layer; and the conductive layer is clamped between the polymer layer and the metal layer, and partially covers the polymer layer along the edge of the composite current collector. The conductive layer is introduced between the polymer layer and the metal layer, so that the conductivity of the composite current collector is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a composite current collector and its preparation method, electrode sheets, battery, and electrical device. Background Technology

[0002] To improve battery current density and safety, one current approach is to use composite current collectors instead of traditional metal foils as the carrier for the positive and negative electrodes. Composite current collectors typically consist of a polymer layer with a metal layer formed on opposite surfaces of the polymer layer using methods such as sputtering. To prevent excessively thick electrodes, the metal layer thickness is generally in the nanometer range or a few micrometers. Especially after the tabs are formed, the small metal layer thickness and insufficient metallization result in poor current conductivity, preventing the battery from achieving high-current charging and discharging, and also making it prone to overheating and other problems. Summary of the Invention

[0003] To address the aforementioned problems, this application discloses a composite current collector, its preparation method, electrode sheet, battery, and electrical device. The composite current collector has a conductive layer sandwiched between a polymer layer and a metal layer, effectively increasing the metallization degree and thus improving its current conductivity.

[0004] A first aspect of this application provides a composite current collector, comprising: a polymer layer and a metal layer stacked on both sides of the polymer layer along the thickness direction; wherein the composite current collector further comprises a conductive layer; the conductive layer is sandwiched between the polymer layer and the metal layer, and partially covers the polymer layer along the edge of the composite current collector.

[0005] According to some embodiments of this application, the resistivity of the conductive layer is less than the resistivity of the metal layer. According to some embodiments of this application, the resistivity of the conductive layer is less than 2.5 × 10⁻⁶. -8 Ω / m.

[0006] According to some embodiments of this application, the thickness of the conductive layer is 1-100 nm, and the thickness of the metal layer is 1-10 nm.

[0007] According to some embodiments of this application, along a plane direction perpendicular to the thickness direction, the composite current collector is divided into a tab region adjacent to the edge and a coating region; the conductive layer is disposed in the tab region.

[0008] According to some embodiments of this application, the conductive layer partially overlaps with the coating area.

[0009] A second aspect of this application provides a method for preparing a composite current collector as described above, the method comprising: S1. providing a polymer layer, and forming conductive layers partially covering the polymer layer along the edges of the polymer layer on both sides of the polymer layer in the thickness direction; S2. forming a metal layer on the polymer layer and the conductive layer.

[0010] According to some embodiments of this application, step S1 further includes: thinning along the edge of the polymer layer; or, providing multiple polymer film layers of different sizes to form the polymer layer; the thickness of the portion of the polymer layer adjacent to the edge is less than the thickness of the remaining portion.

[0011] A third aspect of this application provides an electrode sheet comprising the composite current collector as described above or the composite current collector obtained by the preparation method described above.

[0012] A fourth aspect of this application provides a battery including electrode plates as described above.

[0013] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0014] The disclosure of this application will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. Furthermore, similar numbers in the drawings are used to denote similar components, wherein: Figure 1 These are exemplary structural diagrams of composite current collectors according to some embodiments of this application; Figure 2 This is another exemplary structural diagram of the composite current collector shown in some embodiments of this application; Figure 3 This is an exemplary flowchart of a method for preparing a composite current collector according to some embodiments of this application. Detailed Implementation

[0015] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The terms “comprising” or “including” and similar terms used herein mean that an element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “and / or” or “and / or” as used herein include any and all combinations of one or more of the associated listed items.

[0017] The following describes some preferred embodiments of this application. It should be noted that the following description is for illustrative purposes only and is not intended to limit the scope of protection of this application. The steps involved in this application may be performed precisely in sequence, or various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0018] This application discloses a composite current collector, which improves its conductivity by adding a conductive layer to enhance its metallization.

[0019] refer to Figure 1 , Figure 1 This is an exemplary structural diagram of a composite current collector according to some embodiments of this application. Figure 1 As shown, the composite current collector includes a polymer layer 100 along its thickness direction (e.g., Figure 1 The coordinate system shown x Metal layers 200 are stacked on both sides of polymer layer 100 (in the axial direction), and conductive layer 300 is sandwiched between polymer layer 100 and metal layer 200.

[0020] The polymer layer 100 can be used to form the framework of the composite current collector. As an exemplary but non-limiting illustration, the polymer layer 100 can be prepared from polymeric materials such as polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or modified materials of polymeric materials. For example, a composite film formed by coating a polyethylene film or polypropylene film with polymers such as polyvinylidene fluoride (PVDF) or polymethyl methacrylate (PMMA) can serve as the polymer layer 100. Other materials used to constitute the polymer layer 100 include, but are not limited to, polyvinylidene fluoride (PVDF) and its copolymers, polyamide (PA), polyimide (PI), polyamide-imide (PAI), polybutylene succinate (PBS), polyethersulfone (PES), and their modified materials. In some implementations, the polymer layer 100 is a polyethylene film or a polypropylene film. In this application, commercially available polyethylene films or polypropylene films can be used.

[0021] To further increase the conduction area of ​​the composite current collector, the polymer layer 100 may be provided with multiple through holes 110, the interior of which may be filled with conductive material. In some implementations, the through holes 110 may be formed using suitable physical and / or chemical methods. As an example, multiple through holes 110 may be formed by mechanically drilling to remove material from the surface and / or interior of the polymer layer 100. Alternatively, a high-energy laser beam (such as ultraviolet, infrared, femtosecond laser, etc.) may be focused on the surface of the polymer layer 100, and multiple through holes 110 may be formed by melting, vaporizing, or peeling off localized material through photothermal effects (or photochemical effects). Alternatively, a template-assisted method may be used to cover the surface of the polymer layer 100 with a pre-designed template (such as anodized aluminum oxide (AAO), nanosphere arrays, porous silicon wafers, etc.), and the hole structure of the template may be copied onto the polymer layer 100 through physical filling or etching. As another example, chemical pore-opening methods include solvent etching (e.g., utilizing the solubility differences of a component of polymer layer 100 to selectively dissolve that component with a specific solvent to form pores), and plasma etching (e.g., utilizing active ions such as O in plasma). + Ar + Methods such as bombarding the surface of polymer layer 100 with electrons to remove material and form pores through physical sputtering or chemical sputtering, chemical vapor etching (e.g., reacting gaseous reactants such as H2S, Cl2, HF with the components on the surface of polymer layer 100 to generate volatile products and selectively remove material to form pores), and wet chemical etching (e.g., reacting specific chemical solutions such as acids, alkalis, complexing agents, etc. with the components of polymer layer 100 to remove material through solution dissolution or coordination and thus form pores) can also be applied to this application and are not limited thereto.

[0022] In some embodiments, laser etching can be applied to drill holes in the polymer layer 100 to form multiple vias 110. A non-limiting illustration may be that after the polymer layer 100 is cleaned (e.g., rinsed with deionized water, anhydrous ethanol, dried with nitrogen, or vacuum dried) and completely dried, a suitable laser generator (e.g., an ultraviolet laser for the polymer material) is selected, and the optical system is calibrated and the motion platform is adjusted. Based on actual needs, parameters such as the shape, size, density, and depth of the vias 110 are designed, and the laser is controlled using a planned path to begin emitting laser light and etching the polymer layer 100. After completion, the slag generated during the laser etching process is removed by physical cleaning, air purging, or chemical cleaning, ultimately obtaining a polymer layer 100 with multiple vias 110.

[0023] The central axis of the formed through-hole 110 may be wholly or partially offset from the thickness direction of the polymer layer 100. That is, the central axis of the through-hole 110 may be parallel to... x Axis, or off-axisx Axis. The central axis is off-center. x The through hole 110 of the shaft has its central axis aligned with... x The deviation angle between axes can be between 5° and 85°. For example, the deviation angle can be 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, etc., or any value within the above deviation angle range. x More conductive material can be filled into the holes of the shaft, thereby significantly improving the conductivity of the polymer layer 100. Of course, Figure 1 This is merely an example; the through hole 110 could also be entirely offset or vertical, which does not limit this application.

[0024] The conductive material filling the through-hole 110 may include conductive metal particles or conductive polymers. The metal particles may include at least one of Au, Ag, Cu, Pt, Zn, Mg, Al, Ni, Ti, Cr, and Bi. The conductive polymers may include, but are not limited to, polyacetylene (PA), polyaniline (PANI), polypyrrole (PPy), polythiophene (PTh), poly(3,4-ethylenedioxythiophene) PEDOT, PEDOT:PSS, polyisothioindene (PITN), polycarbazole (PCz), hydrochloric acid-doped polyaniline (PANI-HCl), camphor sulfonic acid-doped polyaniline (PANI-CSA), iodine-doped polyacetylene (PA-I2), boron trifluoride-doped polyacetylene (PA-BF3), poly(3-methylthiophene) P3MT, and poly(3-hexylthiophene) P3. HT, sulfuric acid-doped polypyrrole (PPy-H2SO4), carbon nanotube / epoxy resin composites, graphene / polyimide composites, carbon black / polyurethane composites, metal powder / polypropylene composites, carbon fiber / polyetheretherketone (PEEK) composites, graphene oxide / polyethylene glycol (PEG) composites, metal fiber / epoxy resin composites, conductive carbon black / polyvinyl chloride (PVC) composites, carbon nanotube / polylactic acid (PLA) composites, conductive ceramic / polyamide (PA) composites, etc., or any combination thereof.

[0025] The metal layer 200 can be formed on the upper and lower sides of the polymer layer 100 by physical, chemical, or a combination of both methods. For example, the metal layer 200 can be formed on the upper and lower sides of the polymer layer 100 by physical vapor deposition methods such as magnetron sputtering, vacuum evaporation, and ion plating, or by chemical deposition methods such as electroless plating and electroplating. These methods can also be selectively combined; for example, a seed layer can be formed first by magnetron sputtering and then thickened to the target thickness by electroplating, or vapor deposition can be added on top of this to achieve rapid thickening and thus improve production efficiency. Another example is that a single deposition can be completed by pure magnetron sputtering or using an integrated magnetron evaporation machine. In some implementations, the material used to form the metal layer 200 can be selected from at least one of Au, Ag, Cu, Pt, Zn, Mg, Al, Ni, Ti, Cr, and Bi. For example, the material can be aluminum or copper.

[0026] The thickness of the formed metal layer 200 can be 1-10 nm. For example, the thickness of the metal layer 200 can be 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, or any increment or decrease of the above values.

[0027] The conductive layer 300 may partially cover the polymer layer 100 along the edge of the composite current collector. For ease of explanation, (The text continues with further details about the conductive layer 300 and its application in the composite current collector.) Figure 1 The coordinate system shown in the figure y The axis indicates the left and right ends of the composite current collector. z The axis indicates the inner and outer ends of the composite current collector, and the conductive layer 300 partially covers the polymer layer 100 along the left edge of the composite current collector. Of course, Figure 1 As an example only, the conductive layer 300 may also cover the polymer layer 100 along the right, inner, or outer edge of the composite current collector.

[0028] In some implementations, along a plane direction perpendicular to the thickness direction, that is... y In the axial direction, the composite current collector can be divided into a coating area and a tab area. The coating area can be a region used to support the electrode active layer or other functional modification layers. For example, a slurry prepared based on the electrode active material is coated on the coating area and dried to form the electrode active layer. The tab area is not coated and is used to form the tab when forming the electrode sheet. For example, a conventional tab design in which the tab area is cut to form a small tab, or a full tab design that is formed directly using the tab area without cutting. It is known that the tab is generally located at the edge of the electrode sheet, and the conductive layer 300 can be disposed in the tab area. For example, the conductive layer 300 completely overlaps with the tab area.

[0029] The tab serves as a conductive channel between the battery and external electrical devices. Traditional composite current collectors, due to their thin metal layer, suffer from insufficient metallization, thus affecting current conductivity. This application improves the metallization level of the tab region by adding a conductive layer to the tab region of the composite current collector.

[0030] In some implementations, the conductive layer 300 may be located only in the tab region or may completely overlap with the tab region. In other implementations, the conductive layer 300 may partially overlap with the coating region. For example, the area of ​​the conductive layer 300 may be larger than that of the tab region. Since the composite current collector will be subsequently used to fabricate electrode sheets, to prevent the edges of the electrode sheets from being too thick, the thickness of the conductive layer 300 will be less than the thickness of the coating layer (e.g., electrode active layer, functional modification layer, etc.) coated on the coating region of the composite current collector. For example, if the thickness of the coating layer is in the micrometer range, such as 100 μm, then the thickness of the conductive layer 300 may be in the nanometer range. As an example, the thickness of the conductive layer 300 may be 1-100 nm. For example, the thickness of the conductive layer 300 may be any value within the range of 1 nm, 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, etc.

[0031] Similarly, the conductive layer 300 can also be formed on the polymer layer 100 using one or more methods such as magnetron sputtering, vacuum evaporation, ion plating, electroless plating, and electroplating. The material used to form the conductive layer 300 can also be selected from at least one of Au, Ag, Cu, Pt, Zn, Mg, Al, Ni, Ti, Cr, and Bi. For example, the material can be at least one of gold, silver, or copper.

[0032] Furthermore, to further enhance current conductivity, the resistivity of the conductive layer 300 must be lower than that of the metal layer 200. For example, the metal layer 200 can be formed from metallic copper via magnetron sputtering, while the conductive layer 300 can be formed from metallic silver via magnetron sputtering. Simultaneously, the resistivity of the conductive layer 300 must be less than 2.5 × 10⁻⁶. -8 Ω / m. This allows for a significant improvement in the flow conductivity of the composite current collector.

[0033] In some implementations, the conductive layer 300 may be formed before the metal layer 200, thereby sandwiching the conductive layer 300 between the polymer layer 100 and the metal layer 200. That is, the conductive layer 300 may be formed first on the polymer layer 100, and then the metal layer 200 may be formed on the polymer layer 100 and the conductive layer 300. Furthermore, to ensure that the conductive layer 300 covers only the tab region or covers the tab region and adjacent partial coating areas, this can be achieved by partial forming or removal after forming. For example, a mask may be used to block the coating area or part of the coating area, so that the conductive layer 300 is formed only in the tab region, or the tab region and adjacent partial coating areas. For example, a fully covered conductive layer can be formed directly on the polymer layer 100 first, and then all the conductive layers in the coating area or the part of the conductive layer that is not adjacent to the tab area can be removed by mechanical polishing, laser etching or plasma etching, leaving the conductive layer located in the tab area, or the conductive layer in the tab area and the part of the coating area adjacent to the tab area as the conductive layer 300.

[0034] For ease of explanation, in this application, the portion of the polymer layer 100 covered by the conductive layer 300 is referred to as the first portion FA, and the portion not covered by the conductive layer 300 is referred to as the second portion SA. In some implementations, the thickness of the first portion FA can be the same as the thickness of the second portion SA. That is, the conductive layer 300 will be directly formed and covered on the polymer layer 100. This helps to ensure the mechanical strength and stability of the entire composite current collector. In other implementations, refer to... Figure 2 Another exemplary structural diagram of the composite current collector shown shows that the thickness of the first part FA can be less than the thickness of the second part SA. That is, the first part FA of the polymer layer 100 can be thinned first (e.g., by mechanical polishing, laser etching, thinning with a diluent, etc.), or polymer layers of different sizes can be laminated to form the polymer layer 100. For example, two polymer layers can be laminated, with the bottom polymer layer having a larger size than the top polymer layer. The portion of the larger polymer layer not covered by the smaller polymer layer forms the first part FA, and the overlapping portion forms the second part SA. A conductive layer 300 will be formed on top of the first part FA. The sum of the thickness of the formed conductive layer 300 and the thickness of the first part FA will be equal to the thickness of the second part SA. This effectively prevents the electrode sheet formed by the composite current collector from having excessive thickness at the edges (e.g., tabs).

[0035] The composite current collector provided in this application improves its conductivity by adding a conductive layer.

[0036] This application also provides a method for preparing the above-mentioned current collector. As an exemplary but not limiting description, reference is made to... Figure 3 The preparation method may include the following steps: S1. A polymer layer is provided, and conductive layers are formed on both sides of the polymer layer along the edges of the polymer layer in the thickness direction, partially covering the polymer layer; S2. A metal layer is formed on the polymer layer and the conductive layer.

[0037] In some feasible implementations, the polymer layer can be a polyethylene (PE) film layer, a polypropylene (PP) film layer, a polyethylene terephthalate (PET) film layer, or a composite film layer of the above three. The process for forming the conductive layer can use magnetron sputtering. For example, in a vacuum environment, argon ions (Ar)... + After being accelerated by an electric field, the metal target is bombarded, causing target atoms to sputter and deposit on the surface of the polymer layer to form the conductive layer. Alternatively, vacuum evaporation can be used, where the metal is heated to its evaporation point in a vacuum environment, and the evaporated metal atoms are deposited on the surface of the polymer layer to form the conductive layer. In the above processes, the metal used may include at least one of Au, Ag, Cu, Pt, Zn, Mg, Al, Ni, Ti, Cr, and Bi. For example, at least one of gold, silver, or copper.

[0038] When performing the above process, the polymer layer can be masked, thereby forming a conductive layer in a predetermined area, namely the edge region of the polymer layer. For example, a mask can be used to mask the polymer layer, exposing only the edge region. In this way, the formed conductive layer will only cover the edge portion of the polymer layer. Other feasible options include forming a complete conductive layer on the surface of the polymer layer, followed by thinning / grinding / etching to retain the conductive layer located at the edge portion of the polymer layer. Of course, other methods that achieve the same purpose can be applied in this application.

[0039] Alternatively, the polymer layer can be thinned before forming the conductive layer, for example, by thinning the portion adjacent to the edge. The conductive layer will be formed in this portion. For example, the thickness of the formed conductive layer is equal to the thickness of the thinned portion. Alternatively, the polymer layer can be formed by stacking multiple polymer films of different sizes. For example, polymer films of different sizes could be rectangular films of different lengths but the same width. A larger rectangular film is placed below, and a smaller rectangular film is placed above. The final polymer layer is obtained by stacking the films on one side of each film, such as the right edge along the length direction. The thickness of the polymer layer adjacent to the edge will be less than the thickness of the remaining portion. For example, the thickness of the portion adjacent to the left edge (provided by the larger rectangular film in the lower layer) is less than the thickness of the remaining portion (the sum of the thicknesses of the larger and smaller rectangular films). The conductive layer will be formed in this portion, for example, on top of the larger rectangular film.

[0040] In some feasible implementations, the polymer layer may have multiple through-holes. Taking laser drilling as an example, one approach is to keep the position of the laser generator fixed while moving the polymer layer. For instance, the polymer layer can be placed on a moving platform, such as a conveyor belt, and the movement of the polymer layer can be controlled by controlling the movement of the conveyor belt, so that the laser beam emitted by the laser generator can drill holes at different locations in the polymer layer. Another approach is to fix the position of the polymer layer while moving the laser generator. For instance, the polymer layer can be fixed on a sample stage, and the laser generator, in conjunction with a biaxial galvanometer or a movable platform, can adjust and change the position of the emitted laser beam, thereby drilling holes at different locations in the polymer layer. The multiple through-holes can be filled with conductive materials (e.g., conductive metal particles, or conductive polymers). For example, the conductive material can be pressed into the through-holes by mechanical pressure, such as roller pressing. This roller pressing can be multi-pass roller pressing, which can improve the uniformity of the conductive material in the through-holes. Furthermore, the flexibility of the polymer layer can be improved by adjusting the roller pressing temperature to reduce the resistance of the conductive material being pressed into the holes.

[0041] For step S2, the metal layer can be formed using the same or similar methods as the conductive layer. For example, magnetron sputtering or vacuum evaporation can be used. Alternatively, other suitable methods such as ion plating or electroless plating can also be applied. The metal layer is also formed using at least one of Au, Ag, Cu, Pt, Zn, Mg, Al, Ni, Ti, Cr, and Bi. For example, the metal layer includes one of copper or aluminum. After the metal layer is formed on the polymer layer / conductive layer, the final composite current collector is obtained.

[0042] This application also provides an electrode sheet. The electrode sheet includes the aforementioned composite current collector and an electrode active layer located on at least one side of the composite current collector.

[0043] The electrode sheet may include a positive electrode sheet and a negative electrode sheet. The positive electrode sheet includes a positive active layer that may include a positive active material, a first binder, and a first conductive agent. The positive active material may be a material capable of intercalating or deintercalating metal ions such as lithium ions, including lithium-containing transition metal oxides, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal fluorides, transition metal sulfides, or transition metal nitrides. Some examples may be such as LiCoO2, LiNiO2, LiMnO3, LiMn2O3, LiMnO2, Li(NiCoAl)O2, Li2CuO2, LiNi x Mn 2—x O4, LiNi 1—x M xO2 (M=Co, Mn, Al, Cu, Fe, Mg, B or Ga, x=0.01-0.3), LiMn 1—x M x O2 (M = Co, Ni, Fe, Cr, Zn or Ta, x = 0.01-0.1), Li2Mn3MO8 (M = Fe, Co, Ni, Cu or Zn), etc., but not limited to these.

[0044] In some embodiments, the positive electrode active layer may further comprise a solid electrolyte. For example, a polymer solid electrolyte or an inorganic solid electrolyte. The inorganic solid electrolyte may include, but is not limited to, halide solid electrolytes, sulfide solid electrolytes, oxide solid electrolyte materials, nitride solid electrolytes, hydride solid electrolytes, borate solid electrolytes, etc.

[0045] For example, the polymer electrolyte can be composed of a polymer and a lithium salt. The polymers constituting the polymer solid electrolyte can include, but are not limited to, polyether polymers, polycarbonate polymers, polyamide polymers, polyacrylate polymers, polysiloxane polymers, polyphosphazene polymers, polyolefin polymers, polyepoxide polymers, polyphosphate polymers, polyimide polymers, polyurethane polymers, and any combination thereof. For example, homopolymers such as polyethylene oxide (PEO) or copolymers (e.g., PEG-PPG block copolymers or PVDF-HFP) can participate in the formation of the polymer electrolyte. The lithium salt can include, but is not limited to, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiOTF), lithium hexafluorophosphate (LiPF6), lithium hexafluoroborate (LiBF6), lithium difluorooxalate borate (LiDFOB), lithium bis(oxalate borate) (LiBOB), lithium difluorophosphate (LiPO2F2), lithium hexafluoroarsenate, and tris(pentafluoroethyl) Lithium trifluorophosphate, lithium perchlorate, lithium tetrafluoroborate, cyclodifluoromethane 1,1 Lithium bis(sulfonyl)imide, cyclodifluoromethane 1,1 Lithium bis(sulfonyl)imide, lithium bis(perfluoroethanesulfonyl)imide, lithium bis(fluoromalonic acid)borate, lithium tetracyanoborate, lithium dicyanotriazole salt, dicyano Trifluoromethyl Imidazole lithium salt, dicyano Pentafluoroethyl) Imidazole lithium salt or others.

[0046] Halogen solid electrolytes may include, but are not limited to, LaF3, LiCl, LiI, etc., or those with the chemical formula Li a MXb This refers to lithium halide solid electrolytes, where M represents a metallic element or metalloid element, including one or more of B, Si, Ge, As, Sb, Te, Al, Zn, Mg, Ca, Ba, Mn, Cd, Co, Yb, Y, Cr, In, Ga, Sr, Hf, Ti, Ta, Sn, Nb, Er, Sc, etc., and X represents a halogen element such as F, Cl, Br, I, etc. For example, derivatives produced by doping or coating Li₂CdCl₄, Li₂MgCl₄, Li₂CdI₄, Li₂ZnI₄, Li₂ZrCl₆, Li₃YCl₆, Li₃InCl₆, or related materials.

[0047] Sulfide solid electrolytes may include, but are not limited to, Li2S–P2S5 and Li2S–P2S5–MS. x (M=Si, Ge, Sn, 0≤x≤2), Li 9.6 P3S 12 Li7P3S 11 Li7P2S8I, Li 10 SnP2S 12 Li 10 SiP2S 12 Li9P3S9O3, LGPS(Li 10 GeP2S 12 Thio-LISICON (Li 3.25 Ge 0.25 P 0.75 S4), Li6PS5X (X=Cl, Br, I), Li3PS4-X (X=Cl, Br, I), Li4SnS4-X (X=Cl, Br), Li 3.25 Ge 0.25 P 0.75 S4, Li 3.4 Si 0.4 P 0.6 S4, Li 10 GeP2S 11.7 O 0.3 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Li 10.35 Ge 1.35 P 1.65 S 12 Li 10.35 Si 1.35 P 1.65 S 12 Li 9.81 Sn 0.81 P2.19 S 12 Li 10 (Si 0.5 Ge 0.5 P2S 12 Li 10 (Ge 0.5 Sn 0.5 P2S 12 Li 10 (Si 0.5 Sn 0.5 P2S 12 Li6 (PS5) 0.7 (GeS4) 0.3 Cl、Li 7.5 P 2.5 Sn 0.5 S 10.5 Cl 1.5 Li6PS5Cl 0.5 Br 0.5 Li6PS5I 0.2 Cl 0.8 Li5SnS2C l3 Li 10 P3S 12 Cl2, Li7P2S 8.5 Cl 0.5 Derivatives produced by doping or coating with materials such as or any combination thereof or related materials.

[0048] Oxide solid electrolytes can include, but are not limited to, NASICON-type solid electrolytes, such as NASICON-type solid electrolytes, such as Li. 1+x Al x Ge 2—x (PO4)3(LAGP, where 0 ≤ x ≤ 2), Li 1+x Al x Ti 2—x (PO4)3(LATP, where 0 ≤ x ≤ 2), Li 1+x Y x Zr 2—x (PO4)3(LYZP, where 0≤x≤2), Li 1.3 Al 0.3 Ti 1.7 (PO4)3, etc., perovskite-type solid electrolytes such as Li 3x La( 2 / 3—x TiO3(LLTO, where 0) <x<0.25)、LiSr 1.65 Zr 1.3 Ta 1.7 O9、Li 2x—y Sr 1—x Tay Zr 1—y O3 (where x = 0.75y and 0.60 < y < 0.75), LiTi2(PO4)3, LiGeTi(PO4)3, LiGe2(PO4)3, LiHf2(PO4)3, etc., LISICON-type solid electrolytes such as Li 14 ZnGe4O 16 、Li4SiO4, LiGeO4, etc., garnet-type solid electrolytes such as Li7La3Zr2O 12 、Li 6.5 La3Zr 1.75 Te 0.25 O 12 、Li 6.2 Ga 0.3 La 2.95 Rb 0.05 Zr2O 12 、Li 6.85 La 2.9 Ca 0.1 Zr 1.75 Nb 0.25 O 12 、Li 6.25 Al 0.25 La3Zr2O 12 、Li 6.75 La3Zr 1.75 Nb 0.25 O 12 、Li 6.75 La3Zr 1.75 Nb 0.25 O 12 etc., or derivatives produced by doping or coating improvement with any combination or related materials thereof.

[0049] Nitride solid electrolytes can include, but are not limited to, Li3N, Li7PN4, LiSi2N3, Li9N2Cl3, etc. Some suitable but non-limiting hydride solid electrolytes can include, but are not limited to, LiBH4, LiBH4–Li X (X = Cl, Br or I), LiNH2, Li2NH, LiBH4–LiNH2, Li3AlH6, etc. Some suitable but non-limiting borate solid electrolytes can include, but are not limited to, Li2B4O7, Li2O–B2O3–P2O5, Li2B 10 H 10 –Li2B 12 H 12Examples include Li7N2I–0.5LiOH. Derivatives of these electrolytes obtained through substitution, doping, modification, and compositing can also serve as the inorganic solid electrolytes described in this application. For example, bromine (Br)-substituted or partially substituted Li2ZrCl6, such as Li2ZrCl... 6—x Br x Rare earth metals such as lanthanum or yttrium-doped Li6PS5Br, and LLZO deposited on indium (In) surfaces, etc. It should be noted that the above examples are for illustrative purposes only and are not intended to limit the scope of this application.

[0050] The first adhesive can be any known adhesive, including but not limited to polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aromatic polyamide resin, polyamide, polyimide, polyamide-imide, polyacrylonitrile, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polyhexyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, polyhexafluoropropylene, styrene-butadiene rubber, carboxymethyl cellulose, etc., or any combination thereof, which can be used in this application. Copolymers can also be used as adhesives, exemplary of which are copolymers of two or more materials selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, trifluorochloroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, hexadiene, etc. Alternatively, mixtures of two or more materials in the above examples can also be used as adhesives.

[0051] The first conductive agent may include, but is not limited to, carbon-based materials such as graphite (natural or artificial graphite), carbon black (acetylene black or Ketjen black), carbon nanotubes, graphene, etc.; metal-based materials such as metal powders (aluminum powder, nickel powder, etc.), metal oxides (titanium oxide, etc.), metal whiskers (aluminum oxide, oxidizing agents, etc.); conductive polymers such as polyaniline, polypyrrole, polythiophene, etc.; conductive fibers such as carbon fibers, metal fibers, metal compound fibers, polymer fibers, etc.; or other known conductive agents.

[0052] The negative electrode sheet includes a negative electrode active layer that may include a negative electrode active material and at least one of a second binder and a second conductive agent. The negative electrode active material may also be a material containing metal ions capable of intercalating or deintercalating lithium ions, exemplarily, it may be a metallic material (such as Li, Ag, Al, Bi, Cu, Ga, Ge, In, Ni, Pb, Sb, Si, Sn, Sr, Zn, etc., or alloys or compounds of the above metals, such as Li–Sn alloys, Li–Sn–O alloys, Sn, SnO, SnO2, TiO2–Li4Ti5O). 12Li-Al alloys, Ag-C alloys, etc.), carbon materials (such as graphite including natural / artificial graphite, carbon fiber, soft carbon, hard carbon, crystalline carbon, amorphous carbon, etc.), silicon compounds (such as silicon, silicon-carbon composites), or composite materials formed by metals and carbon / silicon.

[0053] The second adhesive may be the same as or similar to the first adhesive, and the second conductive agent may be the same as or similar to the first conductive agent. Please refer to the foregoing descriptions for details.

[0054] The electrode sheet provided in this application can effectively improve the metallization degree of the electrode sheet and enhance its overcurrent capability by using the aforementioned composite current collector.

[0055] This application also provides a battery, which includes a lithium-ion battery or a solid-state battery.

[0056] The lithium-ion battery includes a cell, a package for encapsulating the cell, and an electrolyte injected into the package.

[0057] The battery cell includes the aforementioned electrode plates, namely the positive electrode plate and the negative electrode plate, and a separator located between the positive electrode plate and the negative electrode plate. The separator can be, for example, a PP film, a PE film, or a PP / PE / PP three-layer composite film, or a modified film, such as one coated with a functional ceramic layer. The separator serves to prevent short circuits between the positive and negative electrode plates while allowing active lithium ions to pass through during charging and discharging.

[0058] The battery cell can be a wound battery cell, formed by sequentially stacking and winding the positive electrode, the separator, and the negative electrode. The battery cell can also be a stacked battery cell, comprising multiple stacked positive and negative electrode plates, which are arranged alternately and separated by the separator.

[0059] The encapsulation body may include, but is not limited to, flexible packaging materials, such as aluminum-plastic film. The encapsulation body may also be other suitable materials, and this application is not limited thereto.

[0060] The electrolyte may include organic solvents, electrolyte salts, and additives. The organic solvents may include, but are not limited to, one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), or ethyl propyl carbonate (EPC). The electrolyte salts may include lithium salts, including but not limited to lithium trifluoromethanesulfonylimide (LiTFSI), lithium bis(fluorosulfonylimide) (LiFSI), lithium trifluoromethanesulfonate (LiOTF), lithium hexafluorophosphate (LiPF6), lithium hexafluoroborate (LiBF6), lithium difluorooxalate borate (LiDFOB), lithium bis(oxalate borate) (LiBOB), lithium difluorophosphate (LiPO2F2), and hexafluoroarsenic acid. The additive may be one or more of the following: lithium, lithium tris(pentafluoroethyl)-trifluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium cyclodifluoromethane-1,1-bis(sulfonyl)imide, lithium cyclodifluoromethane-1,1-bis(sulfonyl)imide, lithium bis(perfluoroethanesulfonyl)imide, lithium bis(fluoromalonic acid)borate, lithium tetracyanoborate, lithium dicyanotriazole, lithium dicyano-trifluoromethyl-imidazolium, and lithium dicyano-pentafluoroethyl)-imidazolium. The additive may include, but is not limited to, one or more of vinylene carbonate (VC), ethylene ethylene carbonate (VEC), fluoroethylene carbonate (FEC), succinic anionyl (SN), and adiponitrile (AND).

[0061] The manufacturing process of the lithium-ion battery can be exemplified by assembling the positive electrode, the composite separator, and the negative electrode into a cell, encapsulating the cell in a package, and then performing processes such as electrolyte injection and formation to obtain the lithium-ion battery. Alternatively, other manufacturing processes in the art can be applied here, and no particular limitation is made.

[0062] The solid-state battery uses a solid electrolyte membrane instead of the aforementioned separator and does not contain an electrolyte. The solid electrolyte membrane may include one or more of the aforementioned solid electrolytes. For example, it may be a mixture of a sulfide solid electrolyte and a halide solid electrolyte, or a mixture of an oxide solid electrolyte and two halide solid electrolytes. The use of known conventional solid electrolytes should be considered within the scope of protection of this application without departing from the inventive concept. Specific descriptions of solid electrolytes can be found in the relevant foregoing sections.

[0063] The solid electrolyte membrane can be obtained by high-speed mixing of one or more solid electrolyte particles with necessary binders, conductive agents, or other additives (if any) followed by tableting. For example, raw materials are weighed in proportion and fed into a high-speed mixer for mixing. The homogeneous mixture obtained after mixing can be pressed into a film using molding, calendering, rolling, etc. Taking rolling as an example, the homogeneous mixture can be pre-formed, such as kneaded into blocks or ground into dough, and then placed into a rolling mill for hot rolling. This hot rolling can include multiple rolling processes. For example, multiple rolling processes can be performed by gradually reducing the roll gap, ultimately obtaining a solid electrolyte membrane with the target thickness.

[0064] The solid-state battery can be fabricated by stacking positive electrode, solid electrolyte membrane, and negative electrode in that order, then drawing out tabs to achieve initial fixation and obtain the corresponding battery cell. The battery cell is then isostatically pressed to obtain a finished product, which is then packaged (e.g., using an aluminum-plastic film or a square hard shell) to finally obtain the solid-state battery. Alternatively, other fabrication processes in this field can be applied, and no particular limitation is imposed.

[0065] The battery disclosed in this application uses the aforementioned electrode plates, which can effectively improve the rate performance of the battery.

[0066] This application also provides an electrical device comprising one or more batteries as described above. The batteries are used to power the electrical device. The electrical device may include consumer electronics such as smartphones, tablets, and laptops; electrically powered vehicles such as electric vehicles and hybrid vehicles; industrial robots, energy storage systems, and data centers.

[0067] The present application will be further described in detail below with reference to embodiments. It should be noted that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection claimed in this application.

[0068] Example 1 This embodiment provides a composite current collector, comprising: a polymer layer and metal layers stacked on both sides of the polymer layer along the thickness direction of the polymer layer, wherein the polymer layer includes a PET layer, the metal layer is an aluminum layer, the thickness of the polymer layer is 13nm, and the thickness of the metal layer is 3nm; A conductive layer was formed by magnetron sputtering at 1 cm from the edge of the polymer layer. The conductive layer was made of gold with a resistivity of 1.59 × 10⁻⁸ Ω / m and a thickness of 2 nm.

[0069] Preparation of the positive electrode: A positive electrode slurry is coated on a composite current collector. The positive electrode active material is NCM811, the binder is PVDF, and the conductive agent is super P. They are mixed in a mass ratio of 95:3:2, and NMP is added to prepare the positive electrode slurry. Preparation of the negative electrode: The negative electrode active material graphite, binder SBR, thickener CMC and conductive agent carbon nanotubes are mixed in a mass ratio of 90:3:2:5, deionized water is added to make a negative electrode slurry, which is then coated on a composite current collector to form a negative electrode.

[0070] The positive electrode, separator, and negative electrode are stacked and assembled in sequence to form a battery. The separator is a PE separator. The electrolyte is a mol / L LiPF6 EC / DMC / EMC solution (volume ratio 1:1:1).

[0071] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not have a conductive layer.

[0072] Performance testing Ratio Performance Test ① Place the battery at room temperature of 25℃, charge it with a charging current of 0.1C to the charging cutoff voltage of 4.25V, cutoff current of 0.05C, and let it stand for 1 hour; then discharge it with a constant current of 0.1C to the discharge cutoff voltage of 3.0V, and let it stand for 1 hour. Record the battery's discharge capacity C0.

[0073] ② Place the battery at room temperature of 25℃, charge it at 3C until the charging cutoff voltage is 4.25V and the cutoff current is 0.05C, and let it stand for 1 hour; then discharge it at a constant current of 5C until the discharge cutoff voltage is 3.0V, and let it stand for 1 hour; record the discharge capacity C1 of the battery.

[0074] Rate performance (3C capacity retention rate) = C1 / C0 × 100%.

[0075] Temperature rise test at the electrode Place the battery in a constant temperature test chamber and fix the thermocouple probe to the tab with high-temperature conductive adhesive. Measure the temperature of the tab at a charging current of 0.1C and 5C respectively, and record them as T1 and T5. Temperature rise = T5 - T1.

[0076] The test results are shown in the table below. This application has described the basic concepts. Obviously, for those skilled in the art, the above detailed disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0077] Furthermore, this application uses specific terms to describe its embodiments. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this application do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0078] Similarly, it should be noted that, in order to simplify the description of this application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of this application sometimes combines multiple features into one embodiment or its description. However, this disclosure method does not imply that the subject matter of this application requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of the single embodiments disclosed above.

[0079] Finally, it should be understood that the embodiments described in this application are merely illustrative of the principles of the embodiments of this application. Other modifications may also fall within the scope of this application. Therefore, alternative configurations of the embodiments of this application are considered as examples and not limitations, and are regarded as consistent with the teachings of this application. Accordingly, the embodiments of this application are not limited to the embodiments explicitly described and illustrated in this application.

Claims

1. A composite current collector, comprising: A polymer layer and metal layers stacked on both sides of the polymer layer along the thickness direction of the polymer layer; characterized in that, The composite current collector further includes a conductive layer; the conductive layer is sandwiched between the polymer layer and the metal layer, and partially covers the polymer layer along the edge of the composite current collector.

2. The composite current collector according to claim 1, characterized in that, The resistivity of the conductive layer is less than that of the metal layer.

3. The composite current collector according to claim 1, characterized in that, The resistivity of the conductive layer is less than 2.5 × 10⁻⁶. -8 Ω / m.

4. The composite current collector according to claim 1, characterized in that, The thickness of the conductive layer is 1-100 nm, and the thickness of the metal layer is 1-10 nm.

5. The composite current collector according to claim 1, characterized in that, Along a plane perpendicular to the thickness direction of the polymer layer, the composite current collector is divided into a tab region adjacent to the edge and a coating region; the conductive layer is disposed in the tab region.

6. The composite current collector according to claim 5, characterized in that, The conductive layer partially overlaps with the coated area.

7. The method for preparing the composite current collector according to any one of claims 1-6, characterized in that, The method includes: S1. A polymer layer is provided, and conductive layers are formed on both sides of the polymer layer along the edges of the polymer layer in the thickness direction, partially covering the polymer layer; S2. A metal layer is formed on the polymer layer and the conductive layer.

8. The preparation method according to claim 7, characterized in that, Step S1 further includes: Thinning treatment is performed along the edges of the polymer layer; or, The polymer layer is formed by stacking multiple polymer films of different sizes; the thickness of the polymer layer at the adjacent edges is less than the thickness of the remaining portions.

9. An electrode sheet, characterized in that, The composite current collector includes any one of claims 1-7 or the composite current collector prepared by the method of claim 7 or 8.

10. A battery, characterized in that, Includes the electrode sheet as described in claim 9.

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