A fast-charging porous double-sided bimetallic layer current collector

Abstract

The utility model discloses a kind of fast charging porous double-sided bimetallic layer current collector, belong to the field of current collector, a kind of fast charging porous double-sided bimetallic layer current collector, including support base film, double-sided conductive coating and bimetallic plating layer sequentially arranged from inside to outside, the double-sided conductive coating is composed of first conductive coating and second conductive coating, the first conductive coating and the second conductive coating are respectively arranged on the upper surface and lower surface of the support base film by micro-concave coating, the bimetallic plating layer is composed of first metal plating layer and second metal plating layer, the first metal plating layer and the second metal plating layer are respectively arranged on the upper surface of the first conductive coating and the lower surface of the second conductive coating by electroplating, it can utilize micropore, can make electron or ion penetrate current collector in the direction of vertical current collector, and then shorten ion transmission path, to this end, the charge and discharge speed is improved.

Description

Technical Field

[0001] This utility model relates to the field of current collectors, and more specifically, to a fast-charging porous double-sided double metal layer current collector. Background Technology

[0002] The fast-charging performance of lithium-ion batteries depends not only on the kinetic optimization of electrode active materials, but also on the design of current collectors. As the core carrier connecting active materials and external circuits, current collectors have a profound impact on the polarization loss, heat distribution uniformity and cycle life of batteries at high rates through characteristics such as electronic conduction efficiency, interface contact stability and mechanical strength.

[0003] Currently, the commonly used current collectors are metal foils (copper foil or aluminum foil) or the latest composite metal foils. The batteries have a wound or stacked structure, and the direction of electron or ion flow is from the positive electrode to the negative electrode. Because it is a solid foil, electrons or ions cannot penetrate the current collector in the direction perpendicular to the current collector, so the movement distance is relatively long, resulting in the inability to charge and discharge ultra-fast. Utility Model Content

[0004] 1. Technical problems to be solved

[0005] In view of the problems existing in the prior art, the purpose of this utility model is to provide a fast-charging porous double-sided double metal layer current collector, which can realize rapid charging and discharging.

[0006] 2. Technical Solution

[0007] To solve the above problems, the present invention adopts the following technical solution.

[0008] A fast-charging porous double-sided bimetallic current collector includes a supporting base film, a double-sided conductive coating, and a bimetallic plating layer arranged sequentially from the inside to the outside. The double-sided conductive coating consists of a first conductive coating and a second conductive coating. The first conductive coating and the second conductive coating are respectively disposed on the upper and lower surfaces of the supporting base film by micro-grooving. The bimetallic plating layer consists of a first metal plating layer and a second metal plating layer. The first metal plating layer and the second metal plating layer are respectively disposed on the upper surface of the first conductive coating layer and the lower surface of the second conductive coating layer by electroplating. Micropores are formed on the first metal plating layer, and the bottom of the micropores penetrates to the outer side of the bottom end of the second metal plating layer. An anti-corrosion coating is coated inside the micropores.

[0009] Furthermore, the micropores include, but are not limited to, circular holes, conical holes, flared holes, funnel holes, arc transition holes, or cross holes.

[0010] Furthermore, the anti-corrosion coating is an aluminum oxide ceramic coating, and the anti-corrosion coating is arranged in a ring shape.

[0011] Furthermore, the first conductive coating and the second conductive coating are carbon material coatings or metal particle coatings, the coating thickness of the double-sided conductive coating is 0.01-10 μm, and the particle size of the metal particle coating is 2-500 nm.

[0012] Furthermore, the electroplating thickness of the bimetallic coating is 5-5000 nm, and the current density of the bimetallic coating is 1A-10A / cm2.

[0013] Furthermore, the supporting substrate film includes, but is not limited to, PET ultrathin polymer film, PTFE ultrathin polymer film, PI ultrathin polymer film or PAA current collector ultrathin polymer film, and the thickness of the supporting substrate film is 2-10 μm.

[0014] 3. Beneficial Effects

[0015] Compared with existing technologies, the advantages of this utility model are:

[0016] (1) This scheme utilizes micropores, which allow electrons or ions to penetrate the current collector in the direction perpendicular to the current collector, thereby shortening the ion transport path and thus improving the charging and discharging speed.

[0017] (2) This solution utilizes an anti-corrosion coating, which can play a role in preventing corrosion and avoid the electrolyte from corroding the inner side of the supporting base film, double-sided conductive coating and bimetallic plating. At the same time, it can reinforce the micropores and prevent the supporting base film, double-sided conductive coating and bimetallic plating from separating from each other. It also plays a role in insulation and isolation. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0019] Figure 2 This is an exploded structural diagram of the present invention;

[0020] Figure 3 This is a schematic diagram of the first metal coating structure in this utility model;

[0021] Explanation of the labels in the diagram:

[0022] 1. Supporting base film; 2. Double-sided conductive coating; 3. Bimetallic plating; 4. Micropores; 5. Anti-corrosion coating;

[0023] 21. First conductive coating; 22. Second conductive coating;

[0024] 31. First metal coating; 32. Second metal coating. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the protection scope of the present utility model.

[0026] In the description of this utility model, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "sleeved / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0028] Example 1:

[0029] Please see Figure 1-3A fast-charging porous double-sided bimetallic current collector includes a supporting base film 1, a double-sided conductive coating 2, and a bimetallic plating layer 3 arranged sequentially from the inside out. The double-sided conductive coating 2 consists of a first conductive coating 21 and a second conductive coating 22, which are respectively disposed on the upper and lower surfaces of the supporting base film 1 by micro-grooving. The bimetallic plating layer 3 consists of a first metal plating layer 31 and a second metal plating layer 32, which are respectively disposed on the upper surface of the first conductive coating layer 21 and the lower surface of the second conductive coating layer 22 by electroplating. Micropores 4 are formed on the first metal plating layer 31. The bottom of the micropore 4 extends through the outer side of the bottom end of the second metal plating layer 32, and the interior of the micropore 4 is coated with an anti-corrosion coating 5. By creating micropores 4 on the supporting base film 1, the double-sided conductive coating 2, and the bimetallic plating layer 3, electrons or ions can penetrate the current collector in a direction perpendicular to the current collector, thereby shortening the ion transport path and improving the charging and discharging speed. The anti-corrosion coating 5 can play a role in preventing corrosion, avoiding the electrolyte from corroding the supporting base film 1, the double-sided conductive coating 2, and the bimetallic plating layer 3. At the same time, it can reinforce the micropore 4, preventing the supporting base film 1, the double-sided conductive coating 2, and the bimetallic plating layer 3 from separating, and also playing a role in insulation and isolation.

[0030] Furthermore, the micropores 4 include, but are not limited to, circular pores, conical pores, flared pores, funnel pores, arc transition pores, or cross pores.

[0031] Specifically, if the micropore 4 is a circular pore, the processing of a circular pore is simple, there are no dead corners inside the pore, which can reduce the retention of ions in the pore and make the electrolyte and ions flow more smoothly;

[0032] If the micropore 4 is a conical pore with a gradually changing pore diameter along the ion transport direction, the pore diameter at the position of the first metal coating 31 is 100-200nm, and the pore diameter at the position of the second metal coating 32 is 50-100nm. The pore wall tilt angle is 3-5° and there are no sharp corners. In this way, during operation, the large end inlet can accommodate a large number of ions in the thick coating to avoid inlet congestion, and the small end outlet can ensure the support strength of the second metal coating 32. Ions are transported along the smooth pore wall without backflow, and the resistance is smaller than that of a straight circular pore.

[0033] If the micropore 4 is a trumpet-shaped pore, the structure is arranged in the form of flaring-reducing-flaring. The inlet diameter of the first metal coating 31 is 80-150nm, the narrow pore diameter at the support base film 1 is 30-80nm, the outlet diameter of the second metal coating 32 is 60-120nm, and the pore wall tilt angle is 1-2°. The large pore diameter at both ends can avoid the inlet and outlet from being blocked, and the narrow pore in the middle can enhance the support force of the support base film 1 on the pore, while guiding the directional transport of ions.

[0034] If the micropore 4 is a funnel-shaped hole, the aperture at the positions of the first metal coating 31 and the second metal coating 32 is 80-150nm, and the aperture at the supporting base film 1 is 30-80nm, with no sharp corners on the hole wall; the narrow opening in the middle can disperse the edge stress during winding, and the hole cracking rate is reduced from 10% of the straight circular hole to less than 2%, making it suitable for cylindrical or soft-pack battery winding processes; the wide apertures at both ends ensure ion transport, balancing process stability and fast charging performance;

[0035] If micro-orifice 4 is a circular arc transition hole, the inlet and outlet edges of the hole are rounded and chamfered based on the straight circular hole, with a radius of 5-10nm, a hole diameter of 50-100nm, and a hole spacing of 150-300nm. The circular arc transition avoids stress concentration at the hole edge, and the coating adhesion area at the hole opening is increased by 10%-15% compared to the straight circular hole. After 500 cycles, the coating peeling rate is ≤3% (8% for the straight circular hole), which is suitable for thin coating (200-300nm) current collectors.

[0036] If the micropore 4 is a cross-shaped hole, with the vertically penetrating main hole as the core and the hole diameter being 50-100nm, then horizontal branch holes are added inside the bimetallic coating 3, with a hole diameter of 20-50nm and a length of 50-100nm. The branch holes are connected to the main hole, and the ends are ≥50nm from the edge of the coating. The branch holes expand the diffusion range of ions in the bimetallic coating 3, reduce the ion concentration difference around the main hole, and reduce the amount of lithium dendrite formation during high-rate charging compared to straight circular holes, thus extending the cycle life.

[0037] Furthermore, the anti-corrosion coating 5 is an alumina ceramic coating. The anti-corrosion coating 5 is arranged in a ring shape, which can play the roles of anti-corrosion protection, structural reinforcement, and insulation isolation. The alumina ceramic coating has extremely high density (porosity ≤0.5%), which can form a physical barrier on the inner wall of the anti-corrosion coating 5, preventing acidic electrolyte from contacting the inner wall of the supporting base film 1, the double-sided conductive coating 2, and the bimetallic coating 3 through the anti-corrosion coating 5. In addition, the anti-corrosion coating 5 can tightly wrap the micropores 4, enhancing the bonding force between the bimetallic coating 3 and the supporting base film 1.

[0038] Furthermore, the first conductive coating 21 and the second conductive coating 22 are carbon material coatings or metal particle coatings. The coating thickness of the double-sided conductive coating 2 is 0.01-10 μm, and the particle size of the metal particle coating is 2-500 nm. If it is a carbon coating, both sides can be carbon coatings. If it is a metal particle coating, one side is a negative electrode metal particle such as copper particles, and the other side is a positive electrode coating such as aluminum particle coating, with a particle size of 2-500 nm.

[0039] The bimetallic coating 3 has an electroplating thickness of 5-5000 nm and a current density of 1A-10A / cm². The first conductive coating 21, with its contact wire as the negative electrode, is placed in a copper plating bath. A copper sheet is selected as the anode, and current is applied. By controlling the appropriate current density and time, copper plating layers of different thicknesses can be obtained. At this time, the second conductive coating 22, not being in contact with electricity, will not be electroplated with copper. The electroplated copper current collector is then cleaned. The second conductive coating 22, with its contact wire as the negative electrode, is placed in an aluminum plating bath. An aluminum sheet is selected as the anode, and current is applied. By controlling the appropriate current density and time, copper and aluminum layers of different thicknesses can be obtained. At this time, the first conductive coating 21, not being in contact with electricity, will not be electroplated with aluminum.

[0040] Furthermore, the supporting base film 1 includes, but is not limited to, PET ultrathin polymer film, PTFE ultrathin polymer film, PI ultrathin polymer film or PAA current collector ultrathin polymer film, and the thickness of the supporting base film 1 is 2-10um.

[0041] The above description is merely a preferred embodiment of this utility model; however, the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and its improved concept, should be included within the protection scope of this utility model.

Claims

1. A fast-charging porous double-sided bimetallic current collector, comprising a supporting base film (1), a double-sided conductive coating (2), and a bimetallic plating layer (3) arranged sequentially from the inside to the outside, characterized in that: The double-sided conductive coating (2) is composed of a first conductive coating (21) and a second conductive coating (22). The first conductive coating (21) and the second conductive coating (22) are respectively disposed on the upper and lower surfaces of the supporting base film (1) by micro-grooving. The bimetallic plating layer (3) is composed of a first metal plating layer (31) and a second metal plating layer (32). The first metal plating layer (31) and the second metal plating layer (32) are respectively disposed on the upper surface of the first conductive coating layer (21) and the lower surface of the second conductive coating layer (22) by electroplating. The first metal plating layer (31) has micropores (4). The bottom of the micropores (4) penetrates the outer side of the bottom end of the second metal plating layer (32). The interior of the micropores (4) is coated with an anti-corrosion coating (5).

2. The fast-charging porous double-sided double-metallic layer current collector according to claim 1, characterized in that: The micropores (4) include, but are not limited to, circular holes, conical holes, flared holes, funnel holes, arc transition holes, or cross holes.

3. The fast-charging porous double-sided double-metallic layer current collector according to claim 1, characterized in that: The anti-corrosion coating (5) is an aluminum oxide ceramic coating, and the anti-corrosion coating (5) is arranged in a ring.

4. The fast-charging porous double-sided double-metallic layer current collector according to claim 1, characterized in that: The first conductive coating (21) and the second conductive coating (22) are carbon material coatings or metal particle coatings. The coating thickness of the double-sided conductive coating (2) is 0.01-10 μm, and the particle size of the metal particle coating is 2-500 nm.

5. The fast-charging porous double-sided double-metallic layer current collector according to claim 1, characterized in that: The electroplating thickness of the bimetallic coating (3) is 5-5000nm, and the current density of the bimetallic coating (3) is 1A-10A / cm2.

6. The fast-charging porous double-sided double-metallic layer current collector according to claim 1, characterized in that: The supporting base film (1) includes, but is not limited to, PET ultrathin polymer film, PTFE ultrathin polymer film, PI ultrathin polymer film or PAA current collector ultrathin polymer film, and the thickness of the supporting base film (1) is 2-10um.

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