Composite current collector system

Abstract

The invention discloses a composite current collector system, and relates to the technical field of new materials. The device comprises a supporting layer, a first copper layer, a metal transition layer, a second copper layer, an electroplating copper layer and a protection layer, the supporting layer, the first copper layer, the metal transition layer, the second copper layer, the electroplating copper layer and the protection layer are arranged in sequence; the metal transition layer is located between the first copper layer and the second copper layer. The product yield of the composite current collector is improved.

Description

Technical Field

[0001] The invention relates to the technical field of new materials, and in particular to a composite current collector system. Background Art

[0002] The traditional negative electrode current collector of lithium batteries is pure copper foil, which has the potential safety hazard of fire caused by needle puncture. In this regard, composite current collectors came into being. The composite current collector has a "sandwich" structure, with a 4.5-micron polymer layer in the middle and a 1-micron copper layer on each side. The current mainstream process is "magnetron sputtering + water electroplating". First, a conductive layer of tens of nanometers is deposited by magnetron sputtering, then thickened to 1 micron by water electroplating, and then a passivation layer is deposited on the surface. Figure 2 As shown, H0 is a polymer support layer, H1 is a magnetron sputtering conductive layer, H2 is a water electroplating thickening layer, and H3 is a passivation protective layer. Since magnetron sputtering is carried out under high vacuum, the H1 copper layers are in contact with each other when the magnetron sputtering is rolled up, which will form a "cold welding" phenomenon. The H1 copper layers are combined with each other. When the film roll is unrolled, the copper layers on both sides peel off from each other, resulting in uneven plating and light transmission of the H1 copper layer, which causes uneven surface density defects in the overall product. Summary of the invention

[0003] An object of the embodiments of the present invention is to provide a composite current collector system to improve the product yield of the composite current collector.

[0004] To achieve the above purpose, the embodiment of the present invention provides the following solution:

[0005] A composite current collector system, comprising:

[0006] Support layer, first copper layer, metal transition layer, second copper layer, electroplated copper layer and protective layer;

[0007] The support layer, the first copper layer, the metal transition layer, the second copper layer, the electroplated copper layer and the protective layer are arranged in sequence;

[0008] The metal transition layer is located between the first copper layer and the second copper layer.

[0009] Optionally, the metal transition layer includes at least metal nickel, metal chromium or metal iron.

[0010] Optionally, the second copper layer is plated on the metal transition layer, or the second copper layer is deposited on the metal transition layer to obtain a transition layer surface structure; the transition layer surface structure is different from that of the first copper layer.

[0011] Optionally, the transition layer surface structure is used to improve surface conductivity.

[0012] Optionally, the surface structure of the transition layer is also used to make the deposition efficiency of the electroplated copper layer and the stress release of the metal transition layer tend to be consistent.

[0013] Optionally, the first copper layer and the second copper layer are both magnetron sputtered copper layers.

[0014] Optionally, the support layer is a polymer support layer.

[0015] Optionally, the protective layer is a passivation protective layer.

[0016] In an embodiment of the present invention, a support layer, a first copper layer, a metal transition layer, a second copper layer, an electroplated copper layer and a protective layer are arranged in sequence; the metal transition layer is located between the first copper layer and the second copper layer. The second copper layer is deposited on the metal transition layer, and its surface structure is somewhat different from that of the first copper layer, which can effectively improve the "cold welding" phenomenon between the second copper layer and the first copper layer on the lower surface during winding, and the addition of the second copper layer helps to improve the surface conductivity, so that the deposition efficiency of the electroplated copper layers on both sides and the stress release of the plating layers are more consistent, thereby improving the product yield of the composite current collector. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0018] Figure 1 A schematic diagram of a composite current collector system provided by an embodiment of the present invention;

[0019] Figure 2 A structural diagram of a composite current collector system provided by the prior art.

[0020] Explanation of symbols:

[0021] Support layer-H0, first copper layer-H1, metal transition layer-H2, second copper layer-H3, electroplated copper layer-H4, protective layer-H5. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The object of the present invention is to provide a composite current collector system to solve the problem of low product yield of existing composite current collectors.

[0024] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] Figure 1 An exemplary structure of the composite current collector system is shown. Each module is described in detail below.

[0026] Support layer, first copper layer, metal transition layer, second copper layer, electroplated copper layer and protective layer;

[0027] The metal transition layer at least includes: metal nickel, metal chromium or metal iron.

[0028] The second copper layer is plated on the metal transition layer, or the second copper layer is deposited on the metal transition layer to obtain a transition layer surface structure; the transition layer surface structure is different from that of the first copper layer.

[0029] The transition layer surface structure is used to improve surface conductivity.

[0030] The surface structure of the transition layer is also used to make the deposition efficiency of the electroplated copper layer and the stress release of the metal transition layer tend to be consistent.

[0031] The first copper layer and the second copper layer are both magnetron sputtered copper layers.

[0032] The support layer, the first copper layer, the metal transition layer, the second copper layer, the electroplated copper layer and the protective layer are arranged in sequence;

[0033] The metal transition layer is located between the first copper layer and the second copper layer.

[0034] The support layer is a polymer support layer.

[0035] The protective layer is a passivation protective layer.

[0036] In one example, a metal transition layer different from copper is added between two magnetron sputtered copper layers (a first copper layer and a second copper layer), and the metal transition layer includes at least a metal nickel layer, a metal chromium layer or a metal iron layer.

[0037] The first copper layer, the second copper layer and the electroplated copper layer are also applicable to other metals, such as silver, aluminum, nickel, tin and iron. All metals will undergo cold welding to varying degrees under this high vacuum and pressure. However, this current collector is currently designed mainly for batteries. At present, it is basically standard to use copper as the current collector for the negative electrode of the battery and aluminum as the current collector for the positive electrode.

[0038] H0 is a polymer support layer, H1 is a magnetron sputtered copper layer, H2 is other metal transition layers, H3 is a magnetron sputtered copper layer, H4 is an electroplated copper layer, and H5 is a passivation protective layer.

[0039] Polymer support layers such as PET, PP, PI, PPS, PE, etc. The main purpose of the composite current collector is to reduce the thickness of the copper layer and the overall weight. At present, only the polymer layer has a relatively composite design purpose.

[0040] The protective layer is a passivation layer that prevents direct contact with air and does not affect the conductive properties. It is difficult for other types to meet both requirements at the same time.

[0041] Among them, the surface structure of the other metal transition layer H2 (metal transition layer) is different from that of the copper layer. A metal copper layer H3 (second copper layer) is plated on the metal transition layer H2. The second copper layer is deposited on the metal transition layer, and its surface structure is different from that of the copper layer H1 (first copper layer). This can effectively improve the "cold welding" phenomenon between the metal copper layer H3 and the first copper layer H1 on the lower surface during winding. The increase of the metal copper layer H3 helps to improve the surface conductivity, making the deposition efficiency of the electroplated copper layer H4 on both sides and the stress release of the plating more consistent.

[0042] In summary, the embodiment of the present invention comprises: a support layer, a first copper layer, a metal transition layer, a second copper layer, an electroplated copper layer and a protective layer; the support layer, the first copper layer, the metal transition layer, the second copper layer, the electroplated copper layer and the protective layer are arranged in sequence; the metal transition layer is located between the first copper layer and the second copper layer. The present invention improves the product yield of the composite current collector.

[0043] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0044] This article uses specific examples to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only used to help understand the methods and core ideas of the embodiments of the present invention. At the same time, for those skilled in the art, according to the ideas of the embodiments of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the embodiments of the present invention.

Claims

1. A composite current collector system, characterized in that: include: Support layer, first copper layer, metal transition layer, second copper layer, electroplated copper layer and protective layer; The support layer, the first copper layer, the metal transition layer, the second copper layer, the electroplated copper layer and the protective layer are arranged in sequence; The metal transition layer is located between the first copper layer and the second copper layer.

2. The composite current collector system according to claim 1, characterized in that: The metal transition layer at least includes: metal nickel, metal chromium or metal iron.

3. The composite current collector system according to claim 1, characterized in that: The second copper layer is plated on the metal transition layer, or the second copper layer is deposited on the metal transition layer to obtain a transition layer surface structure; the transition layer surface structure is different from that of the first copper layer.

4. The composite current collector system according to claim 3, characterized in that: The transition layer surface structure is used to improve surface conductivity.

5. The composite current collector system according to claim 4, characterized in that: The surface structure of the transition layer is also used to make the deposition efficiency of the electroplated copper layer and the stress release of the metal transition layer tend to be consistent.

6. The composite current collector system according to claim 1, characterized in that: The first copper layer and the second copper layer are both magnetron sputtered copper layers.

7. The composite current collector system according to claim 1, characterized in that: The support layer is a polymer support layer.

8. The composite current collector system according to claim 1, characterized in that: The protective layer is a passivation protective layer.

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