Composite current collector with high conductivity

Abstract

The utility model relates to the technical field of current collectors, in particular to a composite current collector with high conductivity, which comprises a polymer base material layer and metal foil layers positioned on the upper and lower surfaces of the polymer base material layer, blind holes are formed in two side surfaces of the polymer base material layer, and the two side surfaces of the polymer base material layer are filled with metal. The problem of low conductivity of a composite current collector structure in the prior art is solved, and the conductivity and bonding strength of the composite structure are improved by filling the blind holes in the surface of the polymer substrate with the metal.

Description

Technical Field

[0001] This application relates to the technical field of current collectors, and in particular to a composite current collector with high electrical conductivity. Background Art

[0002] Since the metal layers on both sides of the composite foil generally have a thickness of only 1 micron, the overcurrent capacity of the composite foil is limited. When charging and discharging at low rates, there is generally no obvious difference in the charge and discharge curves of the battery cells whether using traditional foils or composite foils. However, when charging and discharging at high rates of 2C and 4C, the performance of the composite foil may be lower than that of the traditional foil.

[0003] Chinese Patent CN202120597147.9, a lightweight composite current collector, including its electrode tab and lithium-ion battery, provides a lightweight composite current collector, including its electrode tab and lithium-ion battery. The composite current collector includes an insulating layer and a metal layer located on at least one surface of the insulating layer. The thickness of the metal layer is 10-80% of the total thickness of the composite current collector. The present utility model adopts the design of a composite current collector to overcome the defects of high areal density and difficulty in manufacturing ultra-thin foils, while taking into account high energy and the structural strength of the electrode tab.

[0004] However, this prior art only considers the aspect of lightweight, does not improve the insulating layer, affects the structural conductivity of the composite current collector, and is more unsuitable for the high-rate charge and discharge problem. Summary of the Utility Model

[0005] In order to overcome the problems existing in the prior art, this application provides a composite current collector with high electrical conductivity.

[0006] The composite current collector with high electrical conductivity provided by this application adopts the following technical solutions:

[0007] A composite current collector with high electrical conductivity includes a polymer substrate layer and metal foil layers located on the upper and lower surfaces of the polymer substrate layer. Blind holes are provided on both side surfaces of the polymer substrate layer and filled with metal.

[0008] By adopting the above technical solutions, by filling the grooves with metal, the conductivity of the composite structure is improved, the composite microstructures such as grooves, internal concave holes and sinkholes in the substrate layer are improved, and the product quality of the composite current collector is improved.

[0009] Preferably, the metal foil layer is a copper foil layer or an aluminum foil layer.

[0010] Preferably, the shapes of the blind holes provided on the polymer substrate layer include one or a combination of more than one of cylinder, frustum of a cone or cone.

[0011] Preferably, for the blind hole with a frustum structure in the blind hole, the opening diameter is smaller than the bottom diameter.

[0012] By adopting the above technical solution, the contact surface between the polymer layer and the metal layer is increased, the bonding force between the metal layer and the polymer layer is improved, and a frustum-shaped blind hole with an opening diameter smaller than the bottom diameter is adopted, and the bonding force between the metal layer and the polymer layer is further improved by means of its shape clamping.

[0013] Preferably, the thickness range of the metal foil layer is 0.5-5 μm.

[0014] Preferably, the metal in the metal foil layer and the metal filled in the blind hole is the same metal, and the two are integrally formed.

[0015] By adopting the above technical solution, the metal foil layer and the metal in the blind hole are integrally formed, and the metal can be filled in the blind holes on both sides of the polymer base layer and the metal layer can be prepared by means of evaporation coating.

[0016] In summary, the present application includes at least one of the following beneficial technical effects:

[0017] 1. The present application solves the problem of low conductivity of the composite current collector structure in the prior art. By filling the blind holes on the surface of the polymer substrate with metal, the conductivity and bonding strength of the composite structure are improved;

[0018] 2. The present application can also improve the composite microstructures such as grooves, concave holes and sinkholes in the substrate layer, can limit the local deposition of active substances during the charge and discharge process of the battery, avoid violent volume changes, thereby prolonging the battery life and improving the electrochemical properties such as the reversible capacity, cycle stability and Coulomb efficiency of the battery. Description of the Drawings

[0019] Figure 1 is a schematic structural diagram of Embodiment 1 of a composite current collector with high conductivity;

[0020] Figure 2 is a schematic structural diagram of Embodiment 2 of a composite current collector with high conductivity;

[0021] Figure 3 is a schematic structural diagram of Embodiment 3 of a composite current collector with high conductivity;

[0022] Figure 4 is a schematic structural diagram of Embodiment 4 of a composite current collector with high conductivity.

[0023] Description of the reference numerals: 1, polymer substrate layer; 11, blind hole; 2, metal foil layer; 3, metal. Detailed Embodiments

[0024] The following is a further detailed description of the present application in conjunction with the attached Figures 1-4 drawings.

[0025] Example 1

[0026] An embodiment of the present application discloses a composite current collector with high electrical conductivity.

[0027] Referring to Figure 1 and Figure 4 , a composite current collector with high electrical conductivity includes a polymer substrate layer 1 and metal foil layers 2 located on the upper and lower surfaces of the polymer substrate layer 1. Blind holes 11 are formed on both side surfaces of the polymer substrate layer 1 and filled with metal 3. By filling the grooves with metal 3, the conductivity of the composite structure is improved, and the composite microstructures such as grooves, concave holes, and sinkholes in the substrate layer are improved, and the quality of the composite current collector product is improved.

[0028] Referring to Figure 1 , the metal foil layer 2 is an aluminum foil layer. The shape of the blind holes 11 formed on the polymer substrate layer 1 is cylindrical. The opening diameter of the frustum-shaped blind holes 11 in the blind holes 11 is smaller than the bottom diameter. The contact area between the polymer layer and the metal 3 layer is increased, and the bonding force between the metal 3 layer and the polymer layer is improved.

[0029] Referring to Figure 1 , the thickness range of the metal foil layer 2 is 1 μm. The metal 3 filled in the metal foil layer 2 and the blind holes 11 is the same metal 3, and the two are integrally formed. The metal 3 in the metal foil layer 2 and the blind holes 11 are integrally formed, and the metal 3 can be filled in the blind holes 11 on both sides of the polymer base layer and the metal 3 layer can be prepared by evaporation plating.

[0030] Example 2

[0031] An embodiment of the present application discloses a composite current collector with high electrical conductivity.

[0032] Referring to Figure 2 , the difference between this embodiment and Example 1 is that the shape of the blind holes 11 formed on the polymer substrate layer 1 is a frustum structure, and a frustum structure blind hole 11 with an opening diameter smaller than the bottom diameter is adopted, and the bonding force between the metal 3 layer and the polymer layer is further improved by the shape clamping method.

[0033] Example 3

[0034] An embodiment of the present application discloses a composite current collector with high electrical conductivity.

[0035] Referring to Figure 3 , the difference between this embodiment and Example 1 is that the shape of the blind holes 11 formed on the polymer substrate layer 1 is a conical structure.

[0036] Example 4

[0037] An embodiment of the present application discloses a composite current collector with high electrical conductivity.

[0038] Refer to Figure 4 , the difference between this embodiment and Embodiment 1 is that the shape of the blind holes 11 formed on the polymer substrate layer 1 is a combination of various shapes such as cylinders, frustums of cones or cones.

[0039] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape and principle of the present application shall be covered within the protection scope of the present application.

Claims

1. A composite current collector with high electrical conductivity, characterized in that: The invention comprises a polymer substrate layer (1) and metal foil layers (2) located on the upper and lower surfaces of the polymer substrate layer (1); blind holes (11) are provided on both side surfaces of the polymer substrate layer (1) and are filled with metal (3); the blind holes (11) provided on the polymer substrate layer (1) have a shape including one or a combination of a cylinder, a truncated cone or a cone; and the opening diameter of the blind hole (11) with a truncated cone structure in the blind hole (11) is smaller than the bottom diameter.

2. A composite current collector with high conductivity according to claim 1, characterized in that: The metal foil layer (2) is a copper foil layer or an aluminum foil layer.

3. A composite current collector with high conductivity according to claim 1, characterized in that: The thickness of the metal foil layer (2) is in the range of 0.5-5 μm.

4. A composite current collector with high conductivity according to claim 1, characterized in that: The metal foil layer (2) and the metal (3) filled in the blind hole (11) are the same metal (3), and the two are integrally formed.

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