Evaporation method of multi-metal composite film and multi-metal composite film

Abstract

The invention discloses an evaporation method of a multi-metal composite film and the multi-metal composite film. A metal coating is formed on a substrate through evaporation plating; in the evaporation coating process, at least two kinds of evaporation boats containing different metals are arranged in a staggered mode, so that a coating is distributed in a natural transition mode in which different metals and metal alloys are alternately arranged. According to the invention, alloy structures with finer crystal grains are formed among the introduced different types of metals, so that the defects among metal crystal boundaries are reduced, a more compact plating layer with fewer defects is formed, and the tensile strength of the plating layer is improved. The plating layer can be formed by multiple times of evaporation, multiple times of evaporation are carried out by changing the number and the arrangement mode of the evaporation boats containing different kinds of metal, so that the plating layer also presents alternate natural transition type distribution of different kinds of metal and metal alloy in the vertical direction, and the bonding strength between the plating layers is improved. The preparation method can be applied to preparation of the composite current collector of the battery, and meets the production requirements of composite current collectors with different properties.

Description

Technical Field

[0001] The invention relates to the technical field of metal coatings, and in particular to a vapor deposition method of a multi-metal composite film and the multi-metal composite film. Background Art

[0002] Composite aluminum foil is a "sandwich" structure formed by plating 1 micron aluminum on the upper and lower surfaces of a 6-micron PET base film through a vacuum evaporation process. The mainstream process of composite aluminum foil is evaporation, which uses vacuum evaporation coating, which is a type of physical vapor deposition. It is a process in which a certain heating evaporation method is used under vacuum conditions to vaporize the coating material, and the particles are deposited and condensed on the surface of the substrate to form a film. The advantage is that the film formation speed is fast and suitable for the growth of high-speed film layers, but the disadvantage is that the film layer is relatively loose, and the bonding force and bonding strength are weak. At present, most production generally uses aluminum oxide as a primer to increase the bonding force between the coating and the base film. Even so, the poor bonding force between the metal layer and the polymer layer in the electrolyte environment system will cause more serious metal delamination, cracking of the metal layer, and discontinuous and uneven cracking. These behaviors will greatly reduce the conductivity of the electrode material and increase the internal resistance of the battery, thereby causing battery safety problems. In order to improve this situation, some people have proposed to use different metal layers to form a composite metal layer to increase the bonding force between the coatings. Although the bonding strength between the coatings can be increased by constructing a composite metal layer, the bonding strength between the same metal layers is not improved, and there is currently no specific effective method to form a composite metal layer by evaporation. Summary of the invention

[0003] The purpose of the present invention is to provide a multi-metal composite film evaporation method and a multi-metal composite film, which can improve the mechanical strength of the metal coating and the bonding force between the coatings, and at the same time can regulate the proportion and distribution of different metals in the coating.

[0004] To achieve the above purpose, the technical solution provided by the present invention is:

[0005] The first aspect of the present application provides a method for evaporating a multi-metal composite film, which forms a metal coating on a substrate by evaporation. During the evaporation coating process, at least two evaporation boats containing different metals are arranged in an alternating manner so that the coating presents a natural transitional distribution of alternating different metals and metal alloys.

[0006] To optimize the above technical solutions, the specific measures taken also include:

[0007] The diffusion ranges of the metal vapors generated in two adjacent evaporation boats partially overlap.

[0008] Furthermore, the evaporation boats are arranged in sequence at equal intervals.

[0009] Furthermore, the proportion and position distribution of the metals on the coating can be controlled by controlling the number and arrangement of evaporation boats containing different metals.

[0010] Preferably, the evaporation coating is performed by multiple evaporation depositions. During two adjacent evaporation depositions, the proportion and position distribution of the metal on each coating layer are controlled by adjusting the number and arrangement of evaporation boats containing different metals.

[0011] The number and arrangement of evaporation boats containing different metals are adjusted by at least one of the following methods: changing the metal type of at least one position of the evaporation boat; increasing or decreasing at least one evaporation boat containing metal.

[0012] The different metals are selected from at least two of zinc, copper, lithium, magnesium, iron, gold, silver, nickel, cobalt, tin, aluminum and lithium.

[0013] Furthermore, before using evaporation boats containing different metals to perform evaporation coating in a staggered manner, a metal oxide primer layer is first formed on the substrate.

[0014] The second aspect of the present application provides a multi-metal composite film, wherein the coating includes at least a first metal zone, a second metal zone and a first transition metal zone in a planar direction, wherein the first transition metal zone is located between the first metal zone and the second metal zone, and wherein the first transition metal zone includes the metal types in the first metal zone and the second metal zone.

[0015] The coating at least includes a third metal zone, a fourth metal zone and a second transition metal zone in the thickness direction. The second transition metal zone is located between the third metal zone and the fourth metal zone, and the second transition metal zone includes metal species in the third metal zone and the fourth metal zone.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The present invention adopts staggered arrangement of evaporation boats containing different metals, and utilizes the principle that after the metal vapor in the evaporation boat diffuses upward in a fan shape, the vapor concentration in the evaporation chamber decreases from the middle to both sides, so that the coating presents a natural transition distribution of different metals and metal alloys alternating in the plane direction, so that an alloy structure with finer grains is formed between the introduced different types of metals, the defects between the metal grain boundaries are reduced, a denser coating with fewer defects is formed, and the tensile strength of the coating is improved.

[0018] The coating of the present invention can also be formed by multiple evaporation. During two adjacent evaporation processes, by changing the number and arrangement of evaporation boats containing different metals, the coating can also present a natural transition distribution of different metals and metal alloys alternating in the vertical direction, further improving the bonding strength between the coatings.

[0019] In the process of multiple evaporation depositions, the type of metal in the evaporation boat at the same position can be changed, and the proportion and position distribution of different metals on the coating can be controlled by increasing or decreasing the number of evaporation boats containing metals.

[0020] The present invention can be applied to the preparation of battery composite current collectors, such as composite aluminum foil containing multi-metal composite aluminum film, which can reduce defects between aluminum grain boundaries, improve the tensile strength of the coating, improve the bonding strength between layers, and obtain composite current collectors with different properties, thereby meeting the production requirements of composite current collectors with different properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 : Schematic diagram of the arrangement of the evaporation boat in the evaporation method of the multi-metal composite film of the present invention. DETAILED DESCRIPTION

[0022] The above contents of the present invention are further described in detail below in the form of embodiments, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the above contents of the present invention belong to the scope of the present invention.

[0023] The present invention adopts at least two evaporation boats containing different metals to be arranged alternately for evaporation coating, so that the coating presents a natural transition distribution of different metals and metal alloys.

[0024] The different metals of the present invention are selected from at least two of zinc, copper, lithium, magnesium, iron, gold, silver, nickel, cobalt, tin, aluminum and lithium.

[0025] The staggered arrangement in the present invention does not simply mean alternating in sequence, i.e. ABABABAB format, but also includes staggered arrangement at intervals, such as ABBABBA format, or AABBBAABBB and so on.

[0026] In a preferred embodiment of the present invention, before using evaporation boats containing different metals to perform staggered evaporation coating, a metal oxide primer layer, such as an aluminum oxide primer layer, is first formed on the substrate.

[0027] The present invention is further described in detail below with reference to specific embodiments, wherein metal 1 is zinc, metal 2 is copper, and metal 3 is lithium.

[0028] Example 1

[0029] In this embodiment, a uniform multi-metal composite coating is formed by simultaneously evaporating two metals. The specific steps are as follows:

[0030] The base film is fixed to the winding trolley, and the film is retracted and passed through. Then the tension is adjusted, with the film release end at 120N and the rewinding end at 100N. After the winding trolley enters the evaporation chamber, vacuum is drawn to 5*10 -3Pa, start the winding trolley, control the speed at 280-300m / min, heat the evaporation boat and feed the aluminum wire at a speed of 300-350mm / min, start the oxygen intake, and apply aluminum oxide primer on the surface of the base film. The vacuum degree is controlled at 5*10 -2 Pa; then the vacuum is broken, and the evaporation boats containing the metals are arranged in the order of metal 1-metal 2-metal 1-metal 2, and a zinc-copper metal coating with a natural transition distribution is formed by evaporation.

[0031] Example 2

[0032] In this embodiment, two metals are evaporated simultaneously, and the number and arrangement of evaporation boats containing different metals are changed to perform two evaporation depositions to form a uniform multi-layer multi-metal composite coating. The specific steps are as follows:

[0033] The base film is fixed to the winding trolley, and the film is retracted and passed through. Then the tension is adjusted, with the film release end at 120N and the rewinding end at 100N. After the winding trolley enters the evaporation chamber, vacuum is drawn to 5*10 -3 Pa, start the winding trolley, control the speed at 280-300m / min, heat the evaporation boat and feed the aluminum wire at a speed of 300-350mm / min, start the oxygen intake, and apply aluminum oxide primer on the surface of the base film. The vacuum degree is controlled at 5*10 -2 Pa; then, the vacuum is broken, and the evaporation boats containing the metals are arranged in sequence according to the manner of metal 1-metal 1-metal 2-metal 1-metal 1-metal 2, and a zinc-copper metal coating with a natural transition distribution is formed by vapor deposition; then, the number of evaporation boats containing metal 1 is increased, and vapor deposition is performed again to reduce the content of metal 2 in the coating. The arrangement method adopted is: metal 1-metal 1-metal 1-metal 2-metal 1-metal 1-metal 1-metal 2, and finally a multi-layer zinc-copper composite coating with a natural transition distribution is formed by vapor deposition.

[0034] Example 3

[0035] In this embodiment, three metals are evaporated multiple times simultaneously, and the evaporation is performed twice by changing the number and arrangement of evaporation boats containing different metals to form a uniform multi-layer multi-metal composite coating. The specific steps are as follows:

[0036] The base film is fixed to the winding trolley, and the film is retracted and passed through. Then the tension is adjusted, with the film release end at 120N and the rewinding end at 100N. After the winding trolley enters the evaporation chamber, vacuum is drawn to 5*10 -3 Pa, start the winding trolley, control the speed at 280-300m / min, heat the evaporation boat and feed the aluminum wire at a speed of 300-350mm / min, start the oxygen intake, and apply aluminum oxide primer on the surface of the base film. The vacuum degree is controlled at 5*10-2 Pa; then, the vacuum is broken, and the evaporation boats containing the metals are arranged in sequence according to the manner of metal 1-metal 2-metal 3-metal 1-metal 2-metal 3, and vapor deposition is performed to form a uniform bimetallic coating; then, the number of evaporation boats containing metal 3 is reduced, and vapor deposition is performed again to reduce the content of metal 3 and increase the content of metal 1 and metal 2. The arrangement method adopted is: metal 1-metal 2-metal 1-metal 2-metal 3-metal 1-metal 2-metal 1-metal 2-metal 3, and finally, a multi-layer zinc-copper-lithium composite coating with a natural transition distribution is formed by vapor deposition.

[0037] Comparative Example

[0038] In this comparative example, a multi-metal coating is formed by plating a layer of zinc and then plating a layer of a second metal copper. The specific steps are as follows:

[0039] The base film is fixed to the winding trolley, and the film is retracted and passed through. Then the tension is adjusted, with the film release end at 120N and the rewinding end at 100N. After the winding trolley enters the evaporation chamber, vacuum is drawn to 5*10 -3 Pa, start the winding trolley, control the speed at 280-300m / min, heat the evaporation boat and feed the zinc wire at a speed of 300-350mm / min, start the oxygen intake at the same time, apply aluminum oxide primer on the surface of the base film, and control the vacuum degree at 5*10-2Pa; then break the vacuum and plate a layer of zinc in the same way; after zinc plating, plate a layer of copper under the same conditions to form a zinc-copper coating.

[0040] Table 1 is the physical data of the composite membrane of the embodiment and the comparative example

[0041]

[0042] From the above test data, we can see that:

[0043] By constructing different metals in alternating and naturally transitional distribution in the direction of the coating plane, an alloy structure with finer grains is formed between the introduced different metals, making the arrangement between metal molecules more compact, thereby improving the tensile strength and peel strength of the composite film;

[0044] By changing the number and arrangement of evaporation boats containing different metals and performing multiple vapor deposition, different metals can be constructed to alternate and naturally transition in the thickness direction of the coating. This can make the metal types of two adjacent layers in the thin film metal layer different at the same position, and further improve the bonding strength between layers.

[0045] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any technician familiar with the profession, without departing from the scope of the technical solution of the present invention, according to the technical essence of the present invention, any simple modification, equivalent replacement and improvement made to the above embodiment still falls within the protection scope of the technical solution of the present invention.

Claims

1. A multi-metal composite film evaporation method, characterized in that: A metal coating is formed on a substrate by evaporation coating. During the evaporation coating process, at least two evaporation boats containing different metals are arranged alternately, so that the coating presents a natural transition distribution of alternating different metals and metal alloys.

2. The evaporation method of a multi-metal composite film according to claim 1, characterized in that: The diffusion ranges of the metal vapors generated in two adjacent evaporation boats partially overlap.

3. The evaporation method of a multi-metal composite film according to claim 1, characterized in that: The evaporation boats are arranged in sequence at equal intervals.

4. The evaporation method of a multi-metal composite film according to claim 1, characterized in that: The proportion and position distribution of the metals on the coating can be controlled by controlling the number and arrangement of evaporation boats containing different metals.

5. The evaporation method of a multi-metal composite film according to claim 1, characterized in that: The evaporation coating is carried out by multiple evaporation methods. During two adjacent evaporation processes, the proportion and position distribution of the metal on each coating layer are controlled by adjusting the number and arrangement of evaporation boats containing different metals.

6. The evaporation method of a multi-metal composite film according to claim 5, characterized in that: The number and arrangement of the evaporation boats containing different metals are adjusted by at least one of the following methods: changing the metal type of at least one position of the evaporation boat; increasing or decreasing at least one evaporation boat containing metal.

7. The evaporation method of a multi-metal composite film according to claim 1, characterized in that: Before using evaporation boats containing different metals to perform staggered evaporation coating, a metal oxide base layer is first formed on the substrate.

8. A multi-metal composite film, characterized in that: The multi-metal composite film includes a coating, which includes at least a first metal zone, a second metal zone and a first transition metal zone in a planar direction. The first transition metal zone is located between the first metal zone and the second metal zone, and the first transition metal zone includes metal species in the first metal zone and the second metal zone.

9. The multi-metal composite film according to claim 8, characterized in that: The coating at least includes a third metal zone, a fourth metal zone and a second transition metal zone in the thickness direction. The second transition metal zone is located between the third metal zone and the fourth metal zone, and the second transition metal zone includes metal species in the third metal zone and the fourth metal zone.

Images