Composite current collector and battery

Abstract

The utility model discloses a composite current collector, a preparation method and a battery. The composite current collector comprises a base material layer; the composite metal layer is arranged on the surface of the base material layer, the composite metal layer comprises m corrosion-resistant layers and n conducting layers, m is an integer larger than or equal to 1, n is an integer larger than or equal to 2, and the corrosion-resistant layers and the conducting layers are alternately stacked in the thickness direction of the base material layer. According to the composite current collector, the conductive layers and the corrosion-resistant layers which are alternately stacked are arranged to replace a traditional single metal conductive layer, and after the composite current collector is cut, the exposed part of the edge of the composite metal layer has better corrosion-resistant performance, so that the service life of the composite current collector is longer.

Description

Technical Field

[0001] This utility model belongs to the field of current collector technology, specifically relating to a composite current collector and battery. Background Technology

[0002] Current collectors are components in batteries used to collect current. To reduce their weight, composite current collectors are becoming increasingly common. Composite current collectors are typically manufactured by continuous plating on a substrate. Upstream manufacturers usually supply a whole roll of composite current collectors, and downstream manufacturers cut them to the required shape. However, while the top and bottom surfaces of composite current collectors are usually protected by a protective layer to prevent oxidation and corrosion of the internal metal, the cut edges expose the internal metal. During charging and discharging, the exposed metal layer at the side edges is the first to corrode as the battery heats up and acidic substances released from the electrolyte rise, easily leading to reduced battery efficiency and shorter battery life. Utility Model Content

[0003] This utility model aims to solve at least one of the technical problems existing in the prior art.

[0004] Therefore, this utility model proposes a composite current collector and its preparation method, which has the advantages of corrosion resistance and long service life.

[0005] The composite current collector according to an embodiment of the present invention includes: a substrate layer; a composite metal layer, wherein the composite metal layer is disposed on the surface of the substrate layer, the composite metal layer includes m corrosion-resistant layers and n conductive layers, wherein m is an integer greater than or equal to 1 and n is an integer greater than or equal to 2, and the corrosion-resistant layers and the conductive layers are alternately stacked along the thickness direction of the substrate layer.

[0006] The beneficial effect of this invention is that by setting alternating layers of conductive and corrosion-resistant layers to replace the traditional single metal conductive layer, the exposed part of the composite metal layer after the composite current collector is cut has better corrosion resistance, thus making the composite current collector have a longer service life.

[0007] According to one embodiment of the present invention, the corrosion-resistant layer is at least one of zinc, tin, nickel, cobalt, chromium, titanium, zirconium, and yttrium.

[0008] According to one embodiment of the present invention, the thickness of the corrosion-resistant layer is 1-20 nm.

[0009] According to one embodiment of the present invention, the conductive layer is one or more of copper, aluminum, silver, nickel, chromium, magnesium, zinc, zirconium, manganese, copper-based alloys, and aluminum-based alloys.

[0010] According to one embodiment of the present invention, the thickness of the composite metal layer is 0.3-3 μm.

[0011] According to one embodiment of the present invention, a bonding layer is provided between the substrate layer and the composite metal layer. The bonding layer is an oxide, nitride, or fluoride of silicon, aluminum, titanium, or yttrium, or a mixture of an oxide, nitride, or fluoride of silicon, aluminum, titanium, or yttrium with a metal or alloy of copper, aluminum, titanium, tin, nickel, chromium, or zinc. The thickness of the bonding layer is 2-50 nm.

[0012] According to one embodiment of the present invention, a protective layer is formed on the side of the composite metal layer away from the substrate layer. The protective layer is a metal of zinc, tin, nickel, cobalt, molybdenum, tungsten, copper, aluminum, chromium, titanium, zirconium, yttrium, or an alloy or oxide formed of two or more of the above metals. The thickness of the protective layer is 1-50 nm.

[0013] According to one embodiment of the present invention, the substrate layer is one of PP, PE, and PET, the thickness of the substrate layer is 2-8μm, and the substrate layer is a general membrane or a microporous membrane.

[0014] According to one embodiment of the present invention, a battery includes the aforementioned composite current collector.

[0015] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0016] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0017] Figure 1 This is a schematic diagram of the composite current collector according to an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of another composite current collector according to an embodiment of the present invention;

[0019] Figure 3 This is a schematic diagram of the structure of the heat insulation layer according to an embodiment of the present utility model;

[0020] Figure label:

[0021] Substrate layer 1, bonding layer 2, composite metal layer 3, protective layer 4, heat insulation layer 5, conductive layer 31, corrosion resistant layer 32. Detailed Implementation

[0022] In the description of this utility model, 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," and "circumferential," etc., indicating orientation or positional relationships, 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, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0023] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of 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.

[0024] The following describes in detail the composite current collector, preparation method, and battery according to embodiments of the present invention.

[0025] like Figure 1 and Figure 2 As shown, the composite current collector according to an embodiment of the present invention includes: a substrate layer 1 and a composite metal layer 3. The composite metal layer 3 is disposed on the surface of the substrate layer 1. The composite metal layer 3 includes m corrosion-resistant layers 32 and n conductive layers 31, where m is an integer greater than or equal to 1 and n is an integer greater than or equal to 2. The corrosion-resistant layers 32 and the conductive layers 31 are alternately stacked along the thickness direction of the substrate layer 1.

[0026] The corrosion-resistant layer 32 is at least one of zinc, tin, nickel, cobalt, chromium, titanium, zirconium, and yttrium. Further, the thickness of the corrosion-resistant layer 32 is 1-20 nm. The conductive layer 31 is one or more of copper, aluminum, silver, nickel, chromium, magnesium, zinc, zirconium, manganese, copper-based alloys, and aluminum-based alloys. Even further, the thickness of the composite metal layer 3 is 0.3-3 μm.

[0027] In other words, such as Figure 1 As shown, the composite metal layer 3 includes a corrosion-resistant layer 32 and two conductive layers 31, with the corrosion-resistant layer 32 located between the two conductive layers 31, as shown. Figure 2As shown, the composite metal layer 3 may further include two corrosion-resistant layers 32 and three conductive layers 31. The first corrosion-resistant layer 32 is located between the first conductive layer 31 and the second conductive layer 31, and the second corrosion-resistant layer 32 is located between the second conductive layer 31 and the third conductive layer 31. In other words, the composite metal layer 3 can be formed by alternating layers of multiple corrosion-resistant layers 32 and multiple conductive layers 31, thereby ensuring that there is a corrosion-resistant layer 32 between two adjacent conductive layers 31.

[0028] Therefore, by setting alternating layers of conductive layer 31 and corrosion-resistant layer 32 to replace the traditional single metal conductive layer, the exposed part of the composite metal layer 3 after the composite current collector is cut has better corrosion resistance, resulting in a longer service life of the composite current collector.

[0029] The conductive layer 31 and the corrosion-resistant layer 32 may share one or more metal materials to make the connection between the common metal materials stronger during the preparation process, thereby improving the strength of the connection between the conductive layer 31 and the corrosion-resistant layer 32.

[0030] According to one embodiment of the present invention, the substrate layer 1 is one of PP, PE, and PET, and the thickness of the substrate layer 1 is 2-8 μm. The substrate layer 1 is a general membrane or a microporous membrane. Preferably, a bonding layer 2 is provided between the substrate layer 1 and the composite metal layer 3. The bonding layer 2 is an oxide, nitride, or fluoride of silicon, aluminum, titanium, or yttrium, or a mixture of an oxide, nitride, or fluoride of silicon, aluminum, titanium, or yttrium with a metal or alloy of copper, aluminum, titanium, tin, nickel, chromium, or zinc. The thickness of the bonding layer 2 is 2-50 nm.

[0031] That is, the non-metallic substrate layer 1 is generally non-conductive, so a bonding layer 2 needs to be sputtered on the substrate layer 1 first to metallize the surface of the substrate layer 1, so as to facilitate the subsequent plating of other metals.

[0032] According to one embodiment of the present invention, a protective layer 4 is formed on the side of the composite metal layer 3 away from the substrate layer 1. The protective layer 4 is a metal of zinc, tin, nickel, cobalt, molybdenum, tungsten, copper, aluminum, chromium, titanium, zirconium, yttrium, or an alloy or oxide formed of two or more of the above metals. The thickness of the protective layer 4 is 1-50 nm.

[0033] By setting a protective layer 4, the corrosion resistance and oxidation resistance of the conductive layer 31 are improved, thereby increasing its service life.

[0034] Preferably, a heat insulation layer 5 is provided between the composite metal layer 3 and the bonding layer 2. The heat insulation layer 5 is composed of zirconium oxide, polyimide, or a mixture of polyimide and metal oxide, and the thickness of the heat insulation layer 5 is 5-50 nm.

[0035] In other words, the conductive layer 31 is usually processed by vapor deposition. The temperature of vapor deposition usually exceeds the melting point of the substrate layer 1. Especially for PP, the melting point of PP is about 170℃ and the melting point of PET is 260℃. Once the substrate layer 1 undergoes thermal deformation during vapor deposition, the entire composite current collector will be scrapped. Therefore, the heat insulation layer 5 can effectively isolate the heat of vapor deposition and prevent the heat of vapor deposition from affecting the substrate layer 1.

[0036] When the heat insulation layer 5 is a mixture of polyimide and metal oxide, the metal oxide accounts for 30-70% by weight. Preferably, polyimide and metal oxide each account for 50%. That is, the thermal conductivity of polyimide is 0.2 W / MK, that of zirconium oxide is 2 W / MK, that of alumina is 20 W / MK, and that of conventional metals is 200-400 W / MK. The material of the heat insulation layer 5 is a low thermal conductivity, high temperature resistant material, which can effectively block the heat during vapor deposition, prevent heat transfer to the substrate layer 1, prevent thermal deformation of the substrate layer 1, and thus ensure the quality of the composite current collector.

[0037] This utility model also discloses a preparation method for preparing the above-mentioned composite current collector, which includes the following steps: firstly, a bonding layer 2 is sputtered on the substrate layer 1, then a conductive layer 31 and a corrosion-resistant layer 32 are alternately deposited on the bonding layer 2 to form a composite metal layer 3 with a sandwich structure, and finally a protective layer 4 is deposited.

[0038] This utility model also discloses a battery, including the above-mentioned composite current collector, which can effectively improve the battery's service life.

[0039] Example 1

[0040] A 5nm thick Ni80Cr20 alloy is sputtered onto a 4.5μm PET substrate layer 1 to form a bonding layer 2. Then, a 0.5μm thick copper layer is deposited on the bonding layer 2 to form a first conductive layer 31. Next, a 3nm thick chromium layer is deposited on the first conductive layer 31 to form a corrosion-resistant layer 32. Then, a 0.5μm thick copper layer is deposited on the corrosion-resistant layer 32 to form a second conductive layer 31. Finally, a 3nm thick chromium layer is deposited on the second conductive layer 31 to form a protective layer 4.

[0041] Example 2

[0042] The difference between Example 2 and Example 1 is that the material of the corrosion-resistant layer 32 is zinc.

[0043] Example 3

[0044] The difference between Example 3 and Example 1 is that the material of the corrosion-resistant layer 32 is nickel.

[0045] Example 4

[0046] The difference between Example 4 and Example 1 is that the material of the corrosion-resistant layer 32 is tin.

[0047] Example 5

[0048] A 5nm thick Ni80Cr20 alloy is sputtered onto a 4.5μm PET substrate layer 1 to form a bonding layer 2. Then, a 0.4μm thick copper layer is deposited on the bonding layer 2 to form a first conductive layer 31. Next, a 2nm thick chromium layer is deposited on the first conductive layer 31 to form a first corrosion-resistant layer 32. Then, a 0.3μm thick copper layer is deposited on the corrosion-resistant layer 32 to form a second conductive layer 31. Then, a 2nm thick chromium layer is deposited on the second conductive layer 31 to form a second corrosion-resistant layer 32. Then, a 0.3μm thick copper layer is deposited on the second corrosion-resistant layer 32 to form a third conductive layer 31. Finally, a 2nm thick chromium layer is deposited on the third conductive layer 31 to form a protective layer 4.

[0049] Comparative Example 1

[0050] A 5nm thick Ni80Cr20 alloy is sputtered onto a 4.5μm PET substrate layer 1 to form a bonding layer 2. Then, a 1μm thick copper layer is deposited on the bonding layer 2 to form a conductive layer. Finally, a 6nm thick chromium layer is deposited on the conductive layer to form a protective layer 4.

[0051] Tests were conducted on Examples 1, 2, 3, 4, and Comparative Example 1. The test method involved cutting a 10cm long and 5cm wide sample from a single composite current collector, immersing the sample in a 0.01 M HF solution at 45 degrees Celsius, and stopping the test when the dissolved copper area exceeded 10%. The time was recorded. The results showed that in Example 1, it took 51 hours for the copper area to dissolve to reach 10%; in Example 2, it took 36 hours; in Example 3, it took 45 hours; in Example 4, it took 39 hours; in Example 5, it took 57 hours; and in Comparative Example 1, it took 33 hours.

[0052] The above comparison shows that by setting the corrosion-resistant layer 32, the corrosion resistance of the composite current collector is effectively improved, thus extending its service life. The more layers of corrosion-resistant layer 32 there are, the better the corrosion resistance.

[0053] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0054] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A composite current collector, characterized in that, include: Substrate layer (1); A bonding layer (2) is disposed on the surface of the substrate layer (1); A heat insulation layer (5) is disposed on the surface of the bonding layer (2) away from the substrate layer (1); A composite metal layer (3) is disposed on the surface of the heat insulation layer (5) away from the bonding layer (2). The composite metal layer (3) includes m corrosion-resistant layers (32) and n conductive layers (31), where m is an integer greater than or equal to 1 and n is an integer greater than or equal to 2. The corrosion-resistant layers (32) and the conductive layers (31) are alternately stacked along the thickness direction of the substrate layer (1).

2. The composite current collector according to claim 1, characterized in that, The corrosion-resistant layer (32) is one of zinc, tin, nickel, cobalt, chromium, titanium, zirconium and yttrium.

3. The composite current collector according to claim 2, characterized in that, The thickness of the corrosion-resistant layer (32) is 1-20 nm.

4. The composite current collector according to claim 3, characterized in that, The conductive layer (31) is one of copper, aluminum, silver, nickel, chromium, magnesium, zinc, zirconium, manganese, copper-based alloys, and aluminum-based alloys.

5. The composite current collector according to claim 4, characterized in that, The thickness of the composite metal layer (3) is 0.3-3 μm.

6. The composite current collector according to claim 1, characterized in that, The bonding layer (2) is an oxide, nitride, or fluoride of silicon, aluminum, titanium, or yttrium, and the thickness of the bonding layer (2) is 2-50 nm.

7. The composite current collector according to claim 1, characterized in that, The composite metal layer (3) has a protective layer (4) formed on the side away from the substrate layer (1), and the thickness of the protective layer (4) is 1-50 nm.

8. The composite current collector according to claim 1, characterized in that, The substrate layer (1) is one of PP, PE, and PET, the thickness of the substrate layer (1) is 2-8μm, and the substrate layer (1) is a general membrane or a microporous membrane.

9. A battery, characterized in that, Includes the composite current collector as described in any one of claims 1-8.

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