Graphite-based composite current collector
By setting non-through grooves and conductive layers in the graphite-based composite current collector, combined with a carbon coating layer, the problems of poor thermal conductivity and insufficient safety of the current collector are solved, achieving higher thermal conductivity and anchoring strength, and improving the safety and lightweight effect of the battery.
Patent Information
- Application Number
- CN202422555123.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-23
- Publication Date
- 2025-10-24
- Estimated Expiration
- 2034-10-23
AI Technical Summary
Existing current collector materials in secondary batteries suffer from insufficient safety, high density, and poor thermal conductivity, especially with a significant temperature rise during high-rate charging and discharging.
A graphite-based composite current collector is used. A non-through groove is formed on the surface of the graphite support layer, and a conductive layer is filled in the groove to form a second groove to increase the anchoring area. A carbon coating layer is combined to enhance the bonding force and improve the adhesion and thermal conductivity of the conductive layer.
It improves the lateral thermal conductivity and anchoring strength of the current collector, enhances the overall thermal conductivity of the battery, and improves safety and weight reduction.
Smart Images
Figure CN223471611U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technology field of current collector, especially to a graphite-based composite current collector. BACKGROUND
[0002] In the secondary battery, the current collector is needed, which is the part of current convergence, and its material is generally aluminum foil or copper foil; in the prior art, a graphite-based composite current collector is proposed for safety consideration, which includes a high polymer support layer and a metal layer arranged on both sides of the support layer.
[0003] The traditional metal foil material as the current collector has some defects in safety performance, and the metal material has a large density and a relatively large weight; for the composite current collector, the safety is better and the quality is lighter than the metal foil material, so it has a lower energy density.
[0004] Considering that the secondary battery has high-rate charging and discharging in the use process, which causes the temperature of the battery to rise, the base material in the composite current collector is generally a high polymer, which has poor heat conduction performance (low thermal conductivity), and the metal conductive layer is generally thin, which has poor transverse heat conduction.
[0005] It needs to be further improved and optimized. SUMMARY
[0006] The utility model at least solves one of the technical problems in the related art to some extent. Therefore, one purpose of the utility model is to provide a graphite-based composite current collector, which can improve the adhesion of the metal layer and ensure the overall heat conduction performance of the current collector.
[0007] The technical scheme of the utility model is as follows:
[0008] A graphite-based composite current collector comprises: a graphite support layer, the graphite support layer has two surfaces in the thickness direction; a plurality of first grooves are formed in at least one surface of the graphite support layer, the first grooves are not arranged through the graphite support layer; an electrically conductive layer is arranged on the surface of the graphite support layer, the electrically conductive layer can be anchored into the first grooves and form second grooves corresponding to the first grooves, so as to further form anchor points on the outer surface of the electrically conductive layer.
[0009] Based on the above technical scheme, the composite current collector with graphite as the base body can increase the transverse heat conduction capacity to some extent; and the first grooves are arranged, so that the electrically conductive layer extends inward in the thickness direction, the anchoring area is increased, the heat transfer area is also increased, and the transverse heat conduction is promoted.
[0010] Further, the first grooves are arranged in an array on the first surface;
[0011] And / or, the first grooves are arranged at different densities.
[0012] Based on the above technical scheme, the first grooves are arranged according to actual needs, and can be uniformly arranged at equal intervals or arranged at uneven distribution density.
[0013] Further, the depth of the first grooves is not more than 1 / 3 of the thickness of the graphite support layer.
[0014] Further, the maximum width of the first grooves is 0.5-5mm, and the interval is 5-50mm.
[0015] Based on the above technical scheme, the strength of the support layer after the grooves are formed can be avoided from being excessively affected.
[0016] Further, the thickness of the conductive layer is not more than 3μm.
[0017] Further, a carbon coating layer is arranged on the surface of the conductive layer, and the carbon coating layer is filled into the second grooves to form an anchoring part.
[0018] Based on the above technical scheme, the carbon coating layer is arranged, and the performance of the subsequent pole piece can be further improved; and due to the arrangement of the second grooves, the carbon coating paste can be locally filled into the second grooves during the carbon coating process to form the anchoring part, increase the bonding area in the second grooves, and thus increase the bonding force of the carbon coating layer.
[0019] Further, the first grooves are arranged on both surfaces of the graphite support layer.
[0020] Further, the conductive layer is arranged on both surfaces of the graphite support layer. DETAILED DESCRIPTION
[0021] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, and are used to explain the present application together with embodiments of the present application, and do not constitute a limitation on the present application. In the drawings:
[0022] Figure 1 is a structural schematic view of the current collector;
[0023] Figure 2 is Figure 1 is a schematic view of the current collector after carbon coating;
[0024] Figure 3 is Figure 1 is a structural schematic view of the double-layer conductive layer.
[0025] In the drawings:
[0026] 1-graphite support layer; 11-first groove; 2-conductive layer; 21-second groove; 3-carbon coating layer; 31-anchoring point;
[0027] 10-first surface; 20-second surface. DETAILED DESCRIPTION
[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application.
[0029] Examples of the described embodiments are shown in the drawings, in which the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as limiting the present application.
[0030] In the prior art, the thermal conductivity of conventional metal foil or composite current collector is relatively poor, which affects the overall safety of the secondary battery.
[0031] To solve the above problems, some embodiments of the present application propose a graphite-based composite current collector, comprising: Figure 1
[0032] The graphite support layer 1 is made of graphite-based (graphite film) material, so it has good thermal and electrical conductivity. The graphite support layer 1 has two surfaces in the thickness direction, i.e. the first surface 10 and the second surface 20 in the Figure 1
[0033] In some embodiments of the present application, a plurality of first grooves 11 are formed on the first surface 10 of the graphite support layer 1, and the first grooves 11 are not through the graphite support layer 1. In some embodiments, the first grooves 2 are arranged in an array on the first surface 10, or they can be distributed according to a certain arrangement rule or based on the tolerance value of the setting position, such as setting relatively dense grooves at some positions and relatively loose grooves at other positions.
[0034] Further, an electrically conductive layer 2 is arranged on the first surface 10 of the graphite support layer 1, the electrically conductive layer 2 is filled and anchored into the first grooves 11, and the second grooves 21 are formed corresponding to the first grooves 11, so as to further form anchor points on the outer surface of the electrically conductive layer 2.
[0035] The graphite support layer 1 can be selected from commercially available conventional graphite paper products, and its thickness is 4-50 μm. Alternatively, it can be a graphite film material made by rolling a high molecular film (PI film) after high temperature graphitization.
[0036] The first groove is formed. In some embodiments of the present application, the first groove is formed based on extrusion molding, such as based on a mold pressing device including a pressing roller and a supporting roller, a gap for the film to pass through is arranged between the pressing roller and the supporting roller, a plurality of convex molds are arranged on the circumference of the pressing roller, a puncture mold head is fixed on the convex mold, and the mold head of the puncture mold head forms the first groove. Of course, the first groove can also be formed based on laser drilling by controlling the laser power, scanning range or spot size to cut the above-mentioned anchoring hole structure.
[0037] In some embodiments of the present application, the depth of the first groove 11 is preferably not more than 1 / 3 of the thickness of the graphite support layer 1; the maximum width of the first groove 2 is preferably 0.5-5mm, and the interval is 5-50mm; the control is within a reasonable range, on the one hand, it is easy to process, and on the other hand, it can also avoid that the hole is too large to affect the tensile strength of the film.
[0038] The conductive layer 2 is formed by evaporation or electroplating, which can form a relatively uniform metal conductive layer on the surface of the graphite support layer 1. The material of the conductive layer is selected from copper, aluminum, gold, silver, nickel, chromium, etc. Further, since the speed of forming the conductive layer 2 per unit length by plating is relatively uniform, the amount of metal deposited in the first groove 11 is basically the same as the amount of metal on the first surface 10. However, due to the larger surface area of the first groove 11, metal crystals will also be attached to the wall of the groove, thus forming a relatively rough wall and increasing the anchoring capacity.
[0039] Due to the existence of the first groove 11, the conductive layer 2 will form a groove, i.e. a second groove 21, during the gradual deposition process, because the volume near the position corresponding to the first groove 11 is larger, thereby increasing the adhesion when the subsequent electrode material is coated. When the thickness of the conductive layer is relatively thin, the bottom surface of the second groove 21 is in the first groove 11, but metal crystals can be deposited on the wall of the first groove 11, so that the conductive performance can be guaranteed.
[0040] The thickness of the conductive layer 2 can be selected in combination with adaptability, and the general thickness is not more than 3μm.
[0041] The composite current collector with graphite as the matrix can increase the transverse heat conduction capacity to a certain extent; and the arrangement of the first groove makes the conductive layer extend inward in the thickness direction, thereby increasing the anchoring area and the heat transfer area and promoting the transverse heat conduction.
[0042] Referring to Figure 2 which shows the case of arranging a carbon coating layer 3 on the surface of the conductive layer 2; at the same time, due to the arrangement of the second groove 21, the carbon coating slurry can be partially filled into the second groove 21 during the carbon coating process to form an anchoring part 31, thereby increasing the bonding area with the second groove 21 and increasing the bonding force of the carbon coating layer.
[0043] Further referring to Figure 3In which the first groove 11 is provided on both surfaces of the graphite support layer 1, and a conductive layer 2 is further formed on both surfaces.
[0044] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings or conventional expressions in the prior art, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.
[0045] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent: A exists, A and B exist, and B exists. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.
[0046] In the present application, "multiple" refers to more than two (including two), and similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).
[0047] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.
Claims
1. A graphite-based composite current collector, characterized by, The graphite support layer has two surfaces in the thickness direction; a plurality of first grooves are formed on at least one surface of the graphite support layer, the first grooves are not through the graphite support layer; a conductive layer is arranged on the surface of the graphite support layer, the conductive layer can be anchored into the first grooves and form second grooves corresponding to the first grooves, so as to further form anchor points on the outer surface of the conductive layer.
2. The graphite-based composite current collector of claim 1, wherein The first grooves are arranged in an array on the first surface.
3. The graphite-based composite current collector of claim 1, wherein The first grooves are arranged at different densities.
4. The graphite-based composite current collector of claim 1, wherein The depth of the first grooves is not more than 1 / 3 of the thickness of the graphite support layer.
5. The graphite-based composite current collector of claim 4, wherein the carbon nanotubes are present in an amount of 0.1 to 10 wt% based on the total weight of the graphite-based composite current collector. The maximum width of the first grooves is 0.5-5 mm.
6. The graphite-based composite current collector of claim 5, wherein, The interval between the first grooves is 5-50 mm.
7. The graphite-based composite current collector of any one of claims 1-6, wherein, The thickness of the conductive layer is not more than 3 μm.
8. The graphite-based composite current collector of claim 7, wherein, A carbon coating layer is arranged on the surface of the conductive layer, the carbon coating layer is filled into the second grooves to form anchor parts.
9. The graphite-based composite current collector of claim 7, wherein, The first grooves are arranged on both surfaces of the graphite support layer.
10. The graphite-based composite current collector of claim 9, wherein, The conductive layer is arranged on both surfaces of the graphite support layer.