Composite current collector, pole piece and battery

Abstract

The utility model discloses a composite current collector, a pole piece and a battery. The composite current collector provided by the utility model comprises a base material layer, a first metal coating and a metal cementation layer, the first metal coating is arranged on at least one side surface of the base material layer; the metal cementation layer is arranged on the surface of the side, away from the base material layer, of the first metal coating; wherein the cementation metallization layer comprises a permeation part extending towards the base material layer, and the permeation part penetrates through the first metal plating layer and is embedded into the base material layer. According to the composite current collector, the conductive layer is thickened to improve the conductivity, and meanwhile, permeation connection of the base material layer is realized through a double glow plasma permeation metallization process, so that the binding force between the base material layer and the metal conductive layer is effectively improved, the use performance of a product is improved, and the service life of the product is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of new energy, and in particular to a composite current collector, a pole piece and a battery. Background Art

[0002] At present, due to the increasingly higher requirements for the energy density of lithium-ion batteries, electrode foils are constantly developing in the direction of being lighter and thinner. Using an organic polymer high molecular layer as a substrate, and using magnetron sputtering, vacuum evaporation, water electroplating and chemical plating to prepare a composite current collector formed by a metal layer on the substrate has become an important research direction.

[0003] The polymer base layer of the current composite current collector has very outstanding electrochemical stability, but its bonding strength with the surface metal coating is poor, which causes the polymer layer and the metal coating to easily delaminate and fall off during use of the composite current collector, seriously affecting the performance and life of the finished battery. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a composite current collector that achieves a penetrating connection to the substrate layer through a double-glow plasma metallization process, thereby effectively improving the bonding strength between the substrate layer and the metal conductive layer.

[0005] The utility model also provides a pole piece having the composite current collector.

[0006] The utility model also provides a battery having the above-mentioned electrode piece.

[0007] The composite current collector according to the first embodiment of the present invention includes:

[0008] substrate layer;

[0009] a first metal coating layer, the first metal coating layer being disposed on at least one side surface of the substrate layer;

[0010] a metal infiltration layer, the metal infiltration layer being disposed on a surface of the first metal plating layer away from the substrate layer;

[0011] The metal-diffused layer includes a penetration portion extending toward the substrate layer, and the penetration portion passes through the first metal plating layer and is embedded in the substrate layer.

[0012] The composite current collector according to the embodiment of the present invention has at least the following beneficial effects:

[0013] The metal layer formed by the double-glow plasma metallization process in this application replaces the metal conductive layer formed by the vacuum evaporation process in the prior art. While thickening the conductive layer to improve the conductivity, the double-glow plasma metallization process realizes the penetration connection of the substrate layer, thereby effectively improving the bonding strength between the substrate layer and the metal conductive layer, and improving the performance and life of the product.

[0014] According to some embodiments of the present invention, the composite current collector further includes a second metal coating, which is disposed on a surface of the metal-infiltrating layer away from the substrate layer, and the thickness of the second metal coating is not less than that of the first metal coating.

[0015] According to some embodiments of the present invention, the thickness d4 of the second metal coating layer is in the range of: 0.5 μm≤d4≤10 μm.

[0016] According to some embodiments of the present invention, the thickness d1 of the substrate layer is in the range of 0 μm≤d1≤15 μm.

[0017] According to some embodiments of the present invention, the thickness d2 of the first metal coating layer is in the range of: 0 μm≤d2≤0.5 μm.

[0018] According to some embodiments of the present invention, the thickness d3 of the metal diffusion layer is in the range of: 0 μm≤d3≤10 μm.

[0019] According to some embodiments of the present invention, the metallization layer is formed by a double glow plasma metallization process.

[0020] According to some embodiments of the present invention, the first metal coating layer is formed by a magnetron sputtering process.

[0021] According to the pole piece of the embodiment of the second aspect of the present invention, the pole piece includes the composite current collector mentioned in any one of the above embodiments.

[0022] The pole piece according to the embodiment of the utility model has at least the following beneficial effects:

[0023] Electrodes using this composite current collector offer superior short-circuit and thermal runaway protection. When the battery breaks due to external impact, virtually no metal burrs are generated, preventing puncture of the battery separator and reducing the risk of battery short circuits. Furthermore, because the polymer material used in the composite current collector melts at high temperatures, creating a short circuit and blocking current flow, it effectively prevents thermal runaway. Even if the battery experiences an internal short circuit due to puncture or other reasons, the fusing action of the composite current collector prevents the short circuit from persisting, thus avoiding the risk of battery combustion or explosion.

[0024] The battery according to the third embodiment of the present invention includes the electrode mentioned in the above embodiment.

[0025] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0027] Figure 1 This is a schematic structural diagram of a composite current collector according to an embodiment of the present invention;

[0028] Figure 2 for Figure 1 A magnified schematic diagram of area A in the middle;

[0029] Figure 3 Schematic diagram of the structure of a composite current collector in another embodiment of the present invention.

[0030] Reference numerals:

[0031] Base material layer 100;

[0032] First metal coating 200;

[0033] Infiltration metal layer 300; deposition portion 310; infiltration portion 320;

[0034] Second metal plating layer 400 . DETAILED DESCRIPTION

[0035] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0036] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0037] In the description of this utility model, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of the terms "first" and "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0038] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0039] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0040] At present, due to the increasingly higher requirements for the energy density of lithium-ion batteries, electrode foils are constantly developing in the direction of being lighter and thinner. Using an organic polymer high molecular layer as a substrate, and using magnetron sputtering, vacuum evaporation, water electroplating and chemical plating to prepare a composite current collector formed by a metal layer on the substrate has become an important research direction.

[0041] The polymer base layer of the current composite current collector has very outstanding electrochemical stability, but its bonding strength with the surface metal coating is poor, which causes the polymer layer and the metal coating to easily delaminate and fall off during use of the composite current collector, seriously affecting the performance and life of the finished battery.

[0042] For example, the conventional composite current collector structure includes a polymer layer, a magnetron sputtering metal layer, a vacuum evaporated metal layer and a water electroplated metal layer. Among them, the polymer layer and the magnetron sputtering metal layer, the magnetron sputtering metal layer and the vacuum evaporated metal layer are all physically adsorbed, and are adsorbed on the polymer layer substrate by van der Waals force. The bonding force is poor, and the metal coating layer and the polymer layer substrate are prone to delamination and detachment.

[0043] To solve the above problems, this application proposes a composite current collector, such as Figure 1As shown, the composite current collector includes a substrate layer 100, a first metal coating layer 200, and a metal-infiltrated layer 300. The substrate layer 100 is made of a polymer material and serves as the intermediate substrate layer of the composite current collector, supporting and isolating the conductive layer. It is understood that polymer materials often have weak electrical conductivity. Therefore, a conductive layer composed of a metal material (such as the first metal coating layer 200 and the metal-infiltrated layer 300) is provided on the substrate layer 100 to improve the conductivity of the composite current collector.

[0044] The first metal coating 200 is provided on the surface of at least one side of the substrate layer 100. It is understandable that the pole piece is divided into a single-sided piece and a double-sided piece. The single-sided piece only needs to be coated with an active material layer on one side of the surface, and the double-sided piece needs to be coated with an active material layer on both sides of the surface. Therefore, depending on the type of pole piece, the composite current collector can also be provided with a first metal coating 200 on one side, or on both sides. The first metal coating 200 can be formed by a coating process such as a magnetron sputtering process, a multi-arc ion plating process, and an ion implantation process. Preferably, the first metal coating 200 is sputter-deposited on the substrate layer 100 by a magnetron sputtering process. The metal film layer produced by the magnetron sputtering process has a relatively uniform texture and a relatively thin thickness, and can serve as the basis for the subsequent setting of the metal diffusion layer 300.

[0045] The metallization layer 300 is disposed on a surface of the first metal coating layer 200 away from the substrate layer 100. That is, the substrate layer 100, the first metal coating layer 200, and the metallization layer 300 are disposed in sequence in a direction away from the substrate layer 100. The metallization layer 300 is formed by a double glow plasma metallization process or other metallization processes.

[0046] Taking the double glow plasma metallization process as an example, in this process, two cathodes are set up in a vacuum-sealed container: one is the source electrode (where the target material is placed), and the other is the workpiece electrode (where the workpiece to be processed is placed). At the same time, an independently controllable power supply is set between the source electrode and the anode, and between the workpiece and the anode. After the vacuum chamber is evacuated and filled with a certain amount of argon gas, when the power is turned on, two sets of glow discharge phenomena will be generated between the anode and the source electrode, and between the anode and the workpiece electrode, forming a double glow layer. Under the action of the bias voltage, the gas is ignited, producing an intense glow discharge, which rapidly heats the workpiece to a high temperature. At the same time, argon ions bombard the source electrode, bombarding the target element from the source surface and transporting it through space at high speed to the workpiece surface. These ions easily diffuse and penetrate the workpiece surface at a high temperature, forming a metallized layer with surface metallurgical bonding.

[0047] like Figure 1 and Figure 2As shown, the metallization layer 300 includes a deposition portion 310 located outside the first metal plating layer 200. The deposition portion 310 is the main part of the metallization layer 300, has a certain thickness, and has a good conductive effect. The metallization layer 300 also includes a penetration portion 320 that penetrates and extends toward the substrate layer 100. The penetration portion 320 is arranged on the side surface of the deposition portion 310 facing the substrate layer 100 and protrudes from the deposition portion 310. The penetration portion 320 is embedded in the first metal plating layer 200, thereby improving the bonding strength between the metallization layer 300 and the first metal plating layer 200. Furthermore, by controlling the thickness of the first metal plating layer 200 and the process parameters of the double glow plasma metallization process, the penetration portion 320 can pass through the first metal plating layer 200 and embed into the substrate layer 100, thereby nesting and connecting the substrate layer 100, the first metal plating layer 200, and the metallization layer 300.

[0048] Based on the above, the metal layer 300 formed by the double glow plasma metallization process in this application replaces the metal conductive layer formed by the vacuum evaporation process in the prior art. While thickening the conductive layer to improve the conductivity, the double glow plasma metallization process realizes the penetration connection of the substrate layer 100, thereby effectively improving the bonding force between the substrate layer 100 and the metal conductive layer, and improving the performance and life of the product.

[0049] Furthermore, the depth D1 of the penetration portion 320 embedded in the substrate layer 100 is within the range of 0 nm ≤ D1 ≤ 500 nm. Within this range, the processing parameters of the double glow plasma metallization process are easily achieved, and the penetration portion 320 and the substrate layer 100 are well bonded.

[0050] Furthermore, the material constituting the substrate layer 100 includes, but is not limited to, polyethylene terephthalate (PET), polypropylene (PP), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyethylene (PE), polypropylene, polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polystyrene (PS), and polyimide (PI), and may be one or a combination of the foregoing materials. The thickness d1 of the substrate layer 100 is in the range of 0 μm ≤ d1 ≤ 15 μm.

[0051] Understandably, polymer materials are less expensive than traditional metal current collector materials (such as copper and aluminum). This is primarily due to their abundant raw materials, relatively simple production processes, and ease of large-scale production. Therefore, using polymer materials as the base material for composite current collectors can significantly reduce battery production costs, which is crucial for improving battery cost-effectiveness and market competitiveness. Furthermore, polymer materials have a much lower density than conductive materials like copper. Therefore, using polymer materials as the base material for composite current collectors can significantly reduce the weight and thickness of the current collector. This increases the proportion of active material in the battery, thereby improving the battery's energy density. This has a positive impact on improving battery endurance and performance. Furthermore, the polymer layer in the composite current collector acts as a "fuse," rapidly melting and shutting off the current in the event of a battery short circuit or overheating, preventing thermal runaway and fire. Furthermore, polymer materials have excellent flame retardancy, further reducing battery safety risks. Therefore, using polymer materials as the base material for composite current collectors can significantly improve battery safety.

[0052] Furthermore, the range of the thickness d2 of the first metal coating 200 is: 0μm≤d2≤0.5μm. It should be noted that the first metal coating 200 is preferably formed by a magnetron sputtering process. Magnetron sputtering technology uses the interaction of electric and magnetic fields to bombard the surface of the target material with high-energy particles, so that the sputtered target atoms or molecules are deposited on the substrate layer 100, thereby forming the first metal coating 200. This process has little effect on the substrate layer 100, and can avoid thermal stress or thermal deformation of the substrate due to high temperature. In addition, the film prepared by the magnetron sputtering process has high purity, good density, and good film uniformity, which can serve as a base for the subsequent double-glow plasma metallization process. Moreover, since the film prepared by the magnetron sputtering process is thin, it can be beneficial to the penetration of the metallization layer 300, thereby improving the bonding force between the metallization layer 300 and the substrate layer 100.

[0053] Among them, the key process parameter ranges of magnetron sputtering are: the rate of magnetron sputtering is 0.1nm / s~100nm / s; the protective gas of magnetron sputtering is one or more of argon and nitrogen; the vacuum degree is ≤2Pa; the constituent materials of the first metal coating 200 include but are not limited to copper, nickel, iron, zinc, gold, silver, titanium, aluminum and their alloys, and can be a combination of one or more of the above materials; the thickness d2 of the magnetron sputtering metal layer is in the range of 0μm≤d2≤0.5μm.

[0054] Furthermore, the key process parameters of double glow plasma metallization are: the protective gas is one or more of argon and nitrogen; the target cathode voltage is 10~1000V; the substrate cathode voltage is 10~1000V; and the target cathode voltage is required to be ≥ the substrate cathode voltage; the vacuum degree is ≤100Pa; the constituent materials of the metallization layer 300 include copper, nickel, iron, zinc, gold, silver, titanium, aluminum and their alloys, and can be a combination of one or more of the above materials; the thickness d3 of the metallization layer 300 is in the range of: 0μm≤d3≤10μm.

[0055] Further, such as Figure 3 As shown, the composite current collector also includes a second metal coating 400, which is arranged on the surface of the metal infiltration layer 300 away from the substrate layer 100, and the thickness of the second metal layer is not less than the thickness of the first metal layer. The second metal coating 400 also mainly plays a thickening role to enhance the conductive effect of the composite current collector. The second metal coating 400 can be formed by a water electroplating process. The composite current collector has conductivity after being treated by a magnetron sputtering process and a double glow plasma metal infiltration process. The water electroplating process is used to place the composite current collector in the electroplating solution and electrify both sides to perform metallization deposition, thereby further thickening the conductive layer to achieve good conductive function of the composite current collector. Specifically, the thickness d4 of the water electroplated metal layer is in the range of 0.5μm≤d4≤10μm.

[0056] It is understandable that the second metal coating layer 400 may also be formed by a coating process such as a multi-arc ion plating process.

[0057] The composite current collector in the above embodiment can be obtained by a method for manufacturing the composite current collector, wherein the method for manufacturing the composite current collector includes the following steps:

[0058] Step S100, preparing a substrate layer 100;

[0059] Step S200 , performing a magnetron sputtering process to form a first metal coating layer 200 on the substrate layer 100 ;

[0060] Step S300: performing a double glow plasma infiltration process to form a metal infiltration layer 300 on the first metal coating layer 200;

[0061] Step S400 : performing a water electroplating process to form a second metal plating layer 400 on the infiltration metal layer 300 .

[0062] The second embodiment of the present application proposes a pole piece, which includes the composite current collector mentioned in any of the above embodiments. It should be explained that the composite current collector can be applied to a positive pole piece or a negative pole piece, and the material composition of the metal conductive layer on the composite current collector can also be adjusted accordingly according to the polarity of the pole piece. For example, when the composite current collector needs to be applied to a positive pole piece, the first metal coating layer 200, the metal infiltration layer 300 and the second metal coating layer 400 of the composite current collector can all be made of aluminum. When the composite current collector needs to be applied to a negative pole piece, the first metal coating layer 200, the metal infiltration layer 300 and the second metal coating layer 400 of the composite current collector can be made of copper.

[0063] It is understandable that the pole piece using this composite current collector has good short-circuit protection and thermal runaway protection. When the battery is broken by external force, almost no metal burrs are generated, which avoids puncturing the battery separator and reduces the risk of battery short circuit. In addition, because the polymer material used in the composite current collector will melt at high temperatures, forming a short circuit, blocking the flow of current, thereby effectively preventing battery thermal runaway. Even if the battery causes an internal short circuit due to puncture or other reasons, the short circuit cannot continue due to the fusing effect of the composite current collector, avoiding the risk of battery combustion and explosion.

[0064] The third embodiment of the present application proposes a battery, which includes the electrode mentioned in the above embodiment, and has good safety performance and a long service life.

[0065] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. In addition, the embodiments of the present invention and the features of the embodiments can be combined with each other unless there is a conflict.

Claims

1. A composite current collector, characterized in that: include: substrate layer; a first metal coating layer, the first metal coating layer being disposed on at least one side surface of the substrate layer; a metal infiltration layer, the metal infiltration layer being disposed on a surface of the first metal plating layer away from the substrate layer; The metal-diffused layer includes a penetration portion extending toward the substrate layer, and the penetration portion passes through the first metal plating layer and is embedded in the substrate layer.

2. The composite current collector according to claim 1, characterized in that The composite current collector further includes a second metal plating layer, which is disposed on a surface of the metal-infiltrating layer away from the substrate layer. The thickness of the second metal plating layer is not less than that of the first metal plating layer.

3. The composite current collector according to claim 2, characterized in that: The thickness d4 of the second metal coating layer is in the range of 0.5 μm≤d4≤10 μm.

4. The composite current collector according to claim 1, characterized in that The thickness d1 of the substrate layer is in the range of 0 μm≤d1≤15 μm.

5. The composite current collector according to claim 1, characterized in that The thickness d2 of the first metal coating layer is in the range of 0 μm≤d2≤0.5 μm.

6. The composite current collector according to claim 1, characterized in that The thickness d3 of the metal diffusion layer is in the range of 0 μm≤d3≤10 μm.

7. The composite current collector according to claim 1, characterized in that: The metallization layer is formed by a double glow plasma metallization process.

8. The composite current collector according to claim 1, wherein: The first metal coating is formed by a magnetron sputtering process.

9. A pole piece, characterized in that: Comprising the composite current collector according to any one of claims 1 to 8.

10. A battery, characterized in that Comprising the pole piece as claimed in claim 9.

Images