Methods for preparing composite copper foil and composite copper foil

Abstract

This application provides a method for preparing composite copper foil and the composite copper foil itself. The method includes: providing a substrate, the substrate including a front surface and a side surface connected to the front surface; forming a stabilizing layer on the side surface of the substrate, wherein the coefficient of thermal expansion of the stabilizing layer is less than the coefficient of thermal expansion of the substrate; forming a copper layer on at least a portion of the front surface of the substrate; and removing the stabilizing layer from the side surface of the substrate. The technical solution of this application can reduce the thermal deformation of the substrate and ensure that the performance of the composite copper foil meets the application requirements.

Description

Technical Field

[0001] This application relates to the field of composite copper foil preparation technology, and in particular to a method for preparing composite copper foil and a composite copper foil. Background Technology

[0002] In battery manufacturing, composite copper foil can be used to replace copper foil as the negative electrode current collector, thereby reducing the amount of metallic copper used. However, the production of composite copper foil typically employs magnetron sputtering, which involves high temperatures. The substrate of the composite copper foil undergoes thermal deformation during the coating process, especially at the edges. High temperatures can easily cause wrinkles at the edges of the substrate, leading to uneven copper deposition thickness during coating and ultimately resulting in the composite copper foil failing to meet performance requirements. Summary of the Invention

[0003] One objective of this application is to provide a method for preparing composite copper foil and the composite copper foil, which can reduce the thermal deformation of the substrate and ensure that the performance of the composite copper foil meets the requirements for use.

[0004] According to one aspect of this application, a method for preparing composite copper foil is provided, the method comprising:

[0005] A substrate is provided, the substrate including a front surface and a side surface connected to the front surface;

[0006] A stabilizing layer is provided on the side surface of the substrate, wherein the coefficient of thermal expansion of the stabilizing layer is smaller than the coefficient of thermal expansion of the substrate;

[0007] A copper layer is formed on at least a portion of the positive surface of the substrate;

[0008] Remove the stabilizing layer from the side surface of the substrate.

[0009] In one aspect, the side surface of the substrate facing the stabilizing layer is a first surface, and the surface of the stabilizing layer facing the substrate is a second surface, wherein the first surface and the second surface are planar.

[0010] In one aspect, the substrate has a plurality of first protrusions on its side surface facing the stabilizing layer, and the stabilizing layer has a plurality of second protrusions on its surface facing the substrate, with a gap between adjacent first protrusions, and the second protrusions are embedded in the gap.

[0011] In one aspect, the step of providing a stabilizing layer on the side surface of the substrate includes:

[0012] The stabilizing layer is adhered to the side surface of the substrate.

[0013] In one aspect, the step of attaching the stabilizing layer to the side surface of the substrate includes:

[0014] The stabilizing layer is adhered and installed around the substrate.

[0015] In one aspect, the front surface of the substrate further includes a coating area and a cutting area, the coating area being located in the middle of the substrate and the cutting area being located at the edge of the substrate;

[0016] The step of forming a copper layer in at least a portion of the positive surface of the substrate includes:

[0017] A copper layer is formed in the coating area of ​​the substrate;

[0018] The step of removing the stabilizing layer from the side surface of the substrate includes:

[0019] The substrate is cut within the cutting area to remove the stabilizing layer and a portion of the substrate's edge.

[0020] In one aspect, the step of cutting the substrate within the cutting area includes:

[0021] A cutting line is selected within the cutting area, and the substrate is cut according to the cutting line, wherein the distance between the cutting line and the copper layer is 20-50mm.

[0022] In one aspect, the thickness of the stabilizing layer is the same as the thickness of the substrate, and the width of the stabilizing layer is between 20 and 50 mm.

[0023] In one aspect, if the width ratio of the stabilizing layer to the substrate is α, then the following condition is satisfied: 1 / 50 ≤ α ≤ 1 / 20.

[0024] To address the aforementioned issues, this application also provides a composite copper foil, which is processed using the composite copper foil preparation method described above, wherein the stabilizing layer is one of polyimide, polyetheretherketone, polyphenylene sulfide, or an industrial liquid crystal polymer.

[0025] In the technical solution of this application, since the coefficient of thermal expansion of the stabilizing layer is smaller than that of the substrate, the change in the stabilizing layer during thermal deformation is less than that of the substrate. By setting the stabilizing layer on the side of the substrate, the edge of the substrate can be stabilized, reducing excessive thermal deformation and thus reducing wrinkles at the edge of the substrate, thereby ensuring that the performance of the composite copper foil meets the application requirements.

[0026] It should be understood that the above general description and the following detailed description are merely exemplary and do not limit this application. Attached Figure Description

[0027] The above and other objectives, features and advantages of this application will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0028] Figure 1 This is a schematic diagram of the process steps for preparing composite copper foil in this application.

[0029] Figure 2 This application Figure 1 A schematic diagram of the process steps for attaching the intermediate stabilizing layer to the side surface of the substrate.

[0030] Figure 3 This application Figure 2 A schematic diagram of the process steps for attaching the intermediate stabilizing layer around the substrate.

[0031] Figure 4 This application Figure 1 A schematic diagram of the process steps for cutting off the stabilizing layer.

[0032] Figure 5 This application Figure 4 A schematic diagram of the process steps for cutting off the stabilizing layer within the cutting area.

[0033] Figure 6 This application Figure 1 A schematic diagram of a structure in which the intermediate stabilizing layer is disposed on the side surface of the substrate.

[0034] Figure 7 This application Figure 6 A schematic diagram of the separation structure between the intermediate stabilizing layer and the substrate.

[0035] Figure 8 This application presents a schematic diagram of the structure in which the stabilizing layer is disposed on the side surfaces around the substrate.

[0036] Figure 9 This application presents a schematic diagram of the structure in which the first protrusion of the substrate and the second protrusion of the stabilizing layer are joined together.

[0037] Figure 10 In this application Figure 9 A schematic diagram of its decomposed structure.

[0038] Figure 11 The first protrusion of the substrate and the second protrusion of the stabilizing layer in this application are square structural diagrams.

[0039] Figure 12 The first protrusion of the substrate and the second protrusion of the stabilizing layer in this application are trapezoidal structural diagrams.

[0040] Figure 13 The first protrusion of the substrate and the second protrusion of the stabilizing layer in this application are schematic diagrams of inverted trapezoidal structures.

[0041] Figure 14 This application presents a schematic diagram of a structure in which a stabilizing layer with a second protrusion is disposed around the substrate.

[0042] The following are the descriptions of the reference numerals:

[0043] 10. Substrate; 20. Stabilizing layer;

[0044] 100, Front surface; 110, First surface; 101, Coating area; 102, Cutting area; 210, Second surface; 111, First protrusion; 211, Second protrusion; 112, Empty space; 1021, Cutting line. Detailed Implementation

[0045] Although this application can be readily embodied in various forms of implementation, only some specific embodiments are shown in the accompanying drawings and will be described in detail in this specification. It is understood that this specification should be regarded as an exemplary illustration of the principles of this application and is not intended to limit the application to what is described herein.

[0046] Therefore, a feature described in this specification is used to illustrate one feature of one embodiment of this application, and does not imply that every embodiment of this application must have the described feature. Furthermore, it should be noted that this specification describes many features. While certain features may be combined to illustrate possible system designs, these features may also be used in other combinations not explicitly stated. Therefore, unless otherwise stated, the described combinations are not intended to be limiting.

[0047] In the embodiments shown in the accompanying drawings, the directional indications (such as up, down, left, right, front, and back) used to explain the structure and movement of the various elements of this application are relative rather than absolute. These descriptions are appropriate when these elements are in the positions shown in the drawings. If the description of the positions of these elements changes, these directional indications also change accordingly.

[0048] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided to make the description of this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The drawings are merely illustrative of this application and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted.

[0049] The preferred embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0050] Example 1

[0051] See Figure 1 and Figure 6 As shown, this application provides a method for preparing composite copper foil, which processes the composite copper foil to obtain the composite copper foil. Composite copper foil typically involves depositing a copper layer on a substrate. By using a different substrate, the amount of metallic copper used is reduced, thereby saving costs. The copper layer is generally deposited on the upper and lower surfaces of the substrate. For example, if the thickness of a normal copper foil is 5µm, by using a substrate, the thickness of the substrate becomes 3µm. A 1µm copper layer is deposited on each of the upper and lower surfaces of the substrate. By replacing the substrate, the 3µm thick copper layer used can be reduced.

[0052] In addition, the substrate is generally a polymer material, such as PET (polyethylene terephthalate) or PP (polypropylene). The substrate itself has a certain degree of flexibility, which ensures that the composite copper foil can be rolled up.

[0053] Methods for preparing composite copper foil include:

[0054] Step S10: A substrate 10 is provided. The substrate 10 includes a front surface 100 and a side surface connecting the front surface 100. The substrate 10 has a certain thickness, and the upper and lower surfaces are the front surfaces 100, the area of ​​which is larger than the area of ​​the side surface. The side surface is disposed between the upper and lower front surfaces 100 and connects them. The substrate 10 has a length, a width, and a thickness. The area of ​​the front surface 100 is calculated by multiplying the length and width, and the area of ​​the side surface is calculated by multiplying the length and thickness.

[0055] In step S20, a stabilizing layer 20 is provided on the side surface of the substrate 10, wherein the coefficient of thermal expansion of the stabilizing layer 20 is less than that of the substrate 10. The coefficient of thermal expansion is a physical quantity that characterizes the thermal expansion properties of an object, that is, the physical quantity that characterizes the degree of increase in the length, area, and volume of an object when heated. After the stabilizing layer 20 is provided on the side surface of the substrate 10, it indicates that the stabilizing layer 20 and the substrate 10 are connected and fixed to each other. When the substrate 10 and the stabilizing layer 20 undergo the coating process together, the substrate 10 and the stabilizing layer 20 are heated and increased. Since the coefficient of thermal expansion of the stabilizing layer 20 is less than that of the substrate 10, the deformation of the stabilizing layer 20 is less than that of the substrate 10 when subjected to the same high temperature. This provides a stabilizing constraint on the edge position of the substrate 10. The stabilizing layer 20 can suppress the edge deformation of the substrate 10, thereby preventing edge wrinkling of the substrate 10.

[0056] In step S30, a copper layer is deposited on at least a portion of the front surface 100 of the substrate 10. After the stabilizing layer 20 is applied, edge deformation of the substrate 10 is reduced. The copper layer is then deposited to ensure uniform thickness. Specifically, copper particles are bombarded from a metal target and deposited on the front surface 100 of the substrate 10 under the influence of an electromagnetic field. Due to the stabilizing effect of the stabilizing layer 20, the edges of the substrate 10 are essentially free from deformation and wrinkles, resulting in relatively smooth edges. Thus, the deposition of the copper layer does not affect its thickness, and the thickness distribution is more uniform between the edges and the center of the substrate 10.

[0057] Step S40: Remove the stabilizing layer 20 from the side surface of the substrate 10. After the copper layer is applied, the stabilizing layer 20 has completed its stabilizing and limiting function on the substrate 10. The stabilizing layer 20 has different properties from the substrate 10. To ensure the stability of the composite copper foil serving as the battery negative electrode, the stabilizing layer 20 can be removed. Furthermore, the copper layer has been deposited and adhered to the surface of the substrate 10, and the adhesion between the copper layer and the substrate 10 is strong due to the magnetron sputtering deposition method. The copper layer is relatively stable on the substrate 10, and the function of the stabilizing layer 20 has been completed, thus the stabilizing layer 20 is removed.

[0058] In this embodiment, because the coefficient of thermal expansion of the stabilizing layer 20 is smaller than that of the substrate 10, the stabilizing layer 20 undergoes less thermal deformation than the substrate 10. By placing the stabilizing layer 20 on the side of the substrate 10, it stabilizes the edge of the substrate 10, reducing excessive thermal deformation and thus minimizing wrinkles at the edge of the substrate 10. This ensures that the performance of the composite copper foil meets the application requirements.

[0059] It should be noted that by setting the stabilizing layer 20, the edge positions of the substrate 10 can be fully utilized when depositing the copper layer. For example, without the stabilizing layer 20, wrinkles easily occur at the edges of the substrate 10, and copper cannot be deposited in many areas at the edges. However, after setting the stabilizing layer 20, the wrinkled areas are reduced or even eliminated. This allows the copper layer to extend towards the edges of the substrate 10, expanding the coverage area of ​​the copper layer, and also makes full use of the material of the substrate 10, preventing the edges of the substrate 10 from being cut off and wasted due to the lack of a copper layer.

[0060] It should be further explained that the stabilizing layer 20 is disposed on the side surface of the substrate 10, and the stabilizing layer 20 has formed an integral part with the substrate 10, thereby reducing the coefficient of thermal expansion of the substrate 10.

[0061] See Figure 7As shown, to facilitate the setting of the stabilizing layer 20, the side surface of the substrate 10 facing the stabilizing layer 20 is the first surface 110, and the surface of the stabilizing layer 20 facing the substrate 10 is the second surface 210. Both the first surface 110 and the second surface 210 are planar. The design of both the first surface 110 and the second surface 210 being planar facilitates the opposing bonding between the stabilizing layer 20 and the substrate 10. The planar nature of the first surface 110 and the second surface 210 makes the surface smoother and easier to adhere.

[0062] See Figure 9 and Figure 10 As shown, to ensure that the stabilizing layer 20 can better prevent excessive edge deformation of the substrate 10, a plurality of first protrusions 111 are provided on the side surface of the substrate 10 facing the stabilizing layer 20, and a plurality of second protrusions 211 are provided on the surface of the stabilizing layer 20 facing the substrate 10. A gap 112 is provided between adjacent first protrusions 111, and the second protrusions 211 are embedded in the gaps 112. The provision of the first protrusions 111 and the second protrusions 211 increases the contact area between the substrate 10 and the stabilizing layer 20. The first protrusions 111 on the substrate 10 increase the area of ​​the side surface of the substrate 10; similarly, the second protrusions 211 on the stabilizing layer 20 also effectively increase the side area of ​​the stabilizing layer 20. The increased area of ​​both enhances the restraining effect of the stabilizing layer 20 on the substrate 10, further preventing excessive edge deformation of the substrate 10.

[0063] The specific structure of the first protrusion 111 and the second protrusion 211 can have various designs.

[0064] For example, both the first protrusion 111 and the second protrusion 211 have a triangular cross section. The mutual interlocking of the first protrusion 111 and the second protrusion 211, and the triangular arrangement of the first protrusion 111 and the second protrusion 211, increases the contact area between the stabilizing layer 20 and the substrate 10.

[0065] Additionally, see Figure 11 As shown, the first protrusion 111 and the second protrusion 211 can also have a square cross-section, with a gap formed between adjacent first protrusions 111, and the second protrusion 211 disposed between adjacent first protrusions 111. The square first protrusions 111 and the square protrusions 211 can also be interlocked together and arranged sequentially to further increase the contact area between the stabilizing layer 20 and the substrate 10. Furthermore, the square protrusions are easy to process and shape.

[0066] Secondly, see Figure 12 As shown, the first protrusion 111 and the second protrusion 211 may also have a trapezoidal cross section. A gap is formed between adjacent first protrusions 111, and the second protrusion 211 is disposed between adjacent first protrusions 111.

[0067] Furthermore, see Figure 13 As shown, the first protrusion 111 and the second protrusion 211 can also be inverted trapezoidal structures, i.e., inverted trapezoidal structures. The space 112 formed between two adjacent first protrusions 111 is also trapezoidal, and the second protrusion 211 is disposed within the trapezoidal space 112. The inverted trapezoidal structure also enables the first protrusion 111 and the second protrusion 211 to form a locking and restraining effect, further preventing the stabilizing layer 20 from separating from the substrate 10. It should be noted that the first protrusion 111 can be integrally formed with the substrate 10, and the second protrusion 211 can be integrally formed with the stabilizing layer 20. After the first protrusion 111 and the second protrusion 211 are set, the substrate 10 and the stabilizing layer 20 are then joined together.

[0068] The first protrusion 111 and the second protrusion 211 described above can be processed on the substrate 10 and the stabilizing layer 20 respectively by punching or laser engraving. Then, adhesive is applied to the first protrusion 111 or the second protrusion 211 to bond the first protrusion 111 and the second protrusion 211 together, thus completing the step of setting the stabilizing layer 20 on the substrate.

[0069] See Figure 2 As shown, the step of forming a stabilizing layer 20 on the side surface of the substrate 10 includes:

[0070] Step S210: Adhere the stabilizing layer 20 to the side surface of the substrate 10. Adhesive bonding is a simple method for setting the stabilizing layer 20. For example, an adhesive layer can be applied to the side surface of the substrate 10 or the stabilizing layer 20, or adhesive layers can be applied to both the side surface of the substrate 10 and the side surface of the stabilizing layer 20. By bonding the adhesive layers together, the stabilizing layer 20 is fixed to the side surface of the substrate 10.

[0071] Alternatively, a stabilizing layer 20 can be thermoformed onto the side surface of the substrate 10. The substrate 10 is typically installed in a roll, has a certain degree of flexibility, and is relatively long and narrow in width.

[0072] When the substrate 10 is subjected to heat deformation, the deformation is more pronounced in the width direction. The stabilizing layer 20 can be disposed on the side surface of the substrate 10 in the length direction or on the side surface in the width direction. The stabilizing layer 20, disposed along the length direction of the substrate 10, can limit the deformation of the substrate 10 in the width direction. The stabilizing layer 20, disposed along the width direction of the substrate 10, can limit the deformation of the substrate 10 in the length direction.

[0073] See Figure 3 , Figure 8 and 14As shown, in order to enhance the confinement effect of the stabilizing layer 20 on the substrate 10, the step of attaching the stabilizing layer 20 to the side surface of the substrate 10 includes:

[0074] In step S211, the stabilizing layer 20 is adhered around the substrate 10. The stabilizing layer 20 covers the entire sidewall surface of the substrate 10. That is, the stabilizing layer 20 is provided along both the length and width directions of the substrate 10, thereby creating a stabilizing and restrictive effect on the substrate 10 in multiple peripheral directions. This further prevents severe deformation of the edges of the substrate 10.

[0075] See Figure 4 and Figure 7 As shown, in order to ensure that the stabilizing layer 20 can be effectively removed, the front surface 100 of the substrate 10 also includes a coating area 101 and a cutting area 102. The cutting area 102 is used to provide a position for cutting the substrate 10, and the cutting area 102 is located at the edge of the coating area 101.

[0076] The step of forming a copper layer in at least a portion of the positive surface of a substrate includes:

[0077] Step S310: A copper layer is deposited in the coating area of ​​the substrate; the coating area 101 is located in the middle of the substrate 10, and the cutting area 102 is located at the edge of the substrate 10; the coating area 101 is used to deposit the copper layer, and the copper layer is deposited in the coating area 101.

[0078] The step of removing the stabilizing layer 20 from the side surface of the substrate 10 includes:

[0079] In step S410, the substrate 10 is cut within the cutting area 102 to remove the stabilizing layer 20 and part of the edge of the substrate 10. During the cutting operation, the cutting point of the cutting mechanism can be aligned with the cutting area 102. Cutting is performed within the cutting area 102, ensuring that the cutting point is within the cutting area 102 and does not cut into the copper layer, thus preventing damage to the copper layer. Simultaneously, the stabilizing layer 20 is also located within the cutting area 102, ensuring that the removal of the stabilizing layer 20 is completed while the substrate 10 is being cut.

[0080] See Figure 5 As shown, to further ensure neatness of the cut, the step of cutting the substrate 10 within the cutting area 102 includes:

[0081] Step S411: Select a cutting line 1021 within the cutting area 102, and cut the substrate 10 according to the cutting line 1021. The cutting line 1021 is parallel to the side surface of the corresponding substrate 10. During the cutting operation, the cutting point moves along the cutting line 1021 to ensure that the side surface of the substrate 10 remains flush after cutting.

[0082] To prevent cutting into the copper layer, the distance between the cutting line 1021 and the copper layer is 20-50mm. This 20-50mm safety distance prevents the cutting mechanism from cutting into the copper layer. This safety distance can be 20mm, or one of the following: 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, 40mm, 41mm, 42mm, 43mm, 44mm, 45mm, 46mm, 47mm, 48mm, 49mm, or 50mm. If the safety distance is less than 20mm, the cutting mechanism may easily touch the copper layer; if the safety distance is greater than 50mm, there will be more remaining space at the edge of the substrate 10, and the stabilizing layer 20 may not be effectively cut off. Therefore, the safety distance is set between 20mm and 50mm.

[0083] To ensure that the stabilizing layer 20 effectively limits wrinkles at the edges of the substrate 10, the thickness of the stabilizing layer 20 is the same as the thickness of the substrate 10, and the width of the stabilizing layer 20 is between 20-50 mm. If the width of the stabilizing layer 20 is less than 20 mm, it is too narrow and easily affected by the deformation of the substrate 10, making it difficult to limit the deformation of the substrate 10. If the width of the stabilizing layer 20 is greater than 50 mm, it is too wide. Since a 50 mm wide stabilizing layer 20 is sufficient to suppress edge deformation of the substrate 10, a width greater than 50 mm would be a waste of material.

[0084] The width of the stabilizing layer 20 can be one of the following: 20mm, 21mm, 22mm, 23mm, 24mm, 25mm, 26mm, 27mm, 28mm, 29mm, 30mm, 31mm, 32mm, 33mm, 34mm, 35mm, 36mm, 37mm, 38mm, 39mm, 40mm, 41mm, 42mm, 43mm, 44mm, 45mm, 46mm, 47mm, 48mm, 49mm, or 50mm.

[0085] In one aspect, if the width ratio of the stabilizing layer 20 to the substrate 10 is α, then the following condition must be met: 1 / 50 ≤ α ≤ 1 / 20. If the width ratio α is less than 1 / 50, the width of the stabilizing layer 20 is too small, making it more susceptible to deformation of the substrate 10 and unable to effectively limit the deformation of the substrate 10. If the width ratio α is greater than 1 / 20, the width of the stabilizing layer 20 is too wide. At a ratio of 1 / 20, the stabilizing layer 20 is already sufficient to suppress edge deformation of the substrate 10; a ratio greater than 1 / 20 would waste material from the stabilizing layer 20. The ratio α can also be one of 1 / 45, 1 / 40, 1 / 35, 1 / 30, or 1 / 25.

[0086] Example 2

[0087] This application also provides a composite copper foil, which is processed using the composite copper foil preparation method described above. The stabilizing layer 20 is one of polyimide, polyetheretherketone, polyphenylene sulfide, or industrial liquid crystal polymer (LCP). Polyimide, polyetheretherketone, polyphenylene sulfide, or industrial liquid crystal polymer all possess excellent thermal stability. The coefficient of thermal expansion of polyimide is between 20 and 30 × 10⁻⁶. -6 / ℃, the coefficient of thermal expansion of polyetheretherketone is 50×10 -6 / ℃, the coefficient of thermal expansion of polyphenylene sulfide is 50×10 -6 The coefficient of thermal expansion of industrial liquid crystal polymerization is 11.3 × 10⁻⁶ °C. -6 / ℃.

[0088] Taking PET material as an example, its coefficient of thermal expansion is 60-80×10⁻⁶ at the magnetron sputtering operating temperature (40℃~60℃). -6 The coefficient of thermal expansion of copper is 17 × 10⁻⁶ m / m·K. -6 The coefficient of thermal expansion (m / m·K) differs significantly between the two. Through the use of stabilizing layer 20, the coefficient of thermal expansion of stabilizing layer 20 ranges from 10 to 50 × 10⁻⁶. -6 With an expansion coefficient of m / m·K (20~100℃), the stabilizing layer 20 has an expansion coefficient close to that of the copper layer, thereby offsetting the deformation of the substrate 10 caused by the heating process.

[0089] The specific implementation methods and beneficial effects of composite copper foil are described in the embodiments of the above-mentioned composite copper foil preparation method, and will not be repeated here.

[0090] Although this application has been described with reference to several typical embodiments, it should be understood that the terminology used is illustrative and exemplary, and not restrictive. Since this application can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A method for preparing composite copper foil, characterized in that, The method for preparing the composite copper foil includes: A substrate is provided, the substrate including a front surface and a side surface connected to the front surface, the front surface including a coating area and a cutting area, the coating area being located in the middle of the substrate and the cutting area being located at the edge of the substrate; A stabilizing layer is provided on the side surface of the substrate, wherein the coefficient of thermal expansion of the stabilizing layer is smaller than the coefficient of thermal expansion of the substrate; A copper layer is formed in the coating area of ​​the substrate; The substrate is cut within the cutting area to remove the stabilizing layer and a portion of the substrate's edge.

2. The method for preparing composite copper foil according to claim 1, characterized in that, The side surface of the substrate facing the stabilizing layer is the first surface, and the surface of the stabilizing layer facing the substrate is the second surface. The first surface and the second surface are planar.

3. The method for preparing composite copper foil according to claim 1, characterized in that, The substrate has a plurality of first protrusions on its side surface facing the stabilizing layer, and the stabilizing layer has a plurality of second protrusions on its surface facing the substrate. A gap is provided between adjacent first protrusions, and the second protrusions are embedded in the gap.

4. The method for preparing composite copper foil according to claim 2 or 3, characterized in that, The step of forming a stabilizing layer on the side surface of the substrate includes: The stabilizing layer is adhered to the side surface of the substrate.

5. The method for preparing composite copper foil according to claim 4, characterized in that, The step of attaching the stabilizing layer to the side surface of the substrate includes: The stabilizing layer is adhered and installed around the substrate.

6. The method for preparing composite copper foil according to claim 1, characterized in that, The step of cutting the substrate within the cutting area includes: A cutting line is selected within the cutting area, and the substrate is cut according to the cutting line, wherein the distance between the cutting line and the copper layer is 20-50mm.

7. The method for preparing composite copper foil according to claim 1, characterized in that, The thickness of the stabilizing layer is the same as the thickness of the substrate, and the width of the stabilizing layer is between 20-50 mm.

8. The method for preparing composite copper foil according to claim 1, characterized in that, If the width ratio of the stabilizing layer to the substrate is α, then the following condition must be met: 1 / 50 ≤ α ≤ 1 / 20.

9. A composite copper foil, characterized in that, The composite copper foil is processed using the composite copper foil preparation method as described in any one of claims 1 to 8, wherein the stabilizing layer is one of polyimide, polyetheretherketone, polyphenylene sulfide, or industrial liquid crystal polymer.

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