Composite copper foil, method for manufacturing the same, and battery

Abstract

This application provides a composite copper foil, a method for manufacturing the same, and a battery. The composite copper foil includes a substrate, a conductive portion, and a copper layer. A groove is formed on the surface of the substrate; the conductive portion is disposed within the groove; and the copper layer is disposed on the surface of the substrate and covers the conductive portion. The technical solution of this application can reduce heat generation in the composite copper foil, thereby reducing overheating inside the battery.

Description

Technical Field

[0001] This application relates to the field of copper foil production technology, and in particular to a composite copper foil, its manufacturing method, and a battery. Background Technology

[0002] Currently, copper foil is primarily made of copper and is typically produced through electrolysis, also known as electrolytic copper foil. Composite copper foil is formed by replacing a portion of the copper with polymer materials. Composite copper foil offers advantages such as high energy density and lower cost.

[0003] However, the reduced copper layer thickness in composite copper foil compared to traditional electrolytic copper foil leads to increased resistance, resulting in more heat generation during battery use. Furthermore, the polymer substrate, acting as an insulator, hinders the dissipation of heat generated during battery operation, accelerating the decomposition of various active materials within the battery, reducing its lifespan, and creating safety hazards due to internal overheating. Summary of the Invention

[0004] One objective of this application is to provide a composite copper foil, a method for manufacturing the same, and a battery, which can reduce heat generation in the composite copper foil and reduce overheating inside the battery.

[0005] According to one aspect of this application, a composite copper foil is provided, the composite copper foil comprising:

[0006] A substrate, wherein a groove is provided on the surface of the substrate;

[0007] A conductive part is disposed within the groove;

[0008] A copper layer is disposed on the surface of the substrate and covers the conductive portion.

[0009] In one aspect, the grooves are provided in a plurality of them, and the plurality of grooves are arranged at equal intervals on the surface of the substrate.

[0010] In one aspect, the conductive portion includes at least one of inorganic non-metallic conductive particles or metallic conductive particles.

[0011] In one aspect, the inorganic non-metallic conductive particles include at least one of graphene or carbon nanotubes;

[0012] The conductive metal particles include at least one of gold, silver, copper, iron, nickel, tin, or aluminum.

[0013] In one aspect, the composite copper foil further includes a conductive seed layer disposed between the conductive portion and the copper layer, the conductive seed layer being made of the same material as the copper layer.

[0014] In one aspect, the thickness of the conductive part is D, which satisfies: 0.1um ≤ D ≤ 0.5um.

[0015] In one aspect, the substrate has a first surface and a second surface disposed opposite to each other, the groove on the first surface being a first groove and the groove on the second surface being a second groove, the first groove and the second groove being interleaved.

[0016] Furthermore, to address the aforementioned problems, this application also provides a method for manufacturing a composite copper foil, the method comprising:

[0017] Provide base materials;

[0018] A groove is formed on the surface of the substrate;

[0019] The surface of the substrate is covered and the groove is exposed, and conductive particles are deposited in the groove to form a conductive portion;

[0020] A copper layer is formed on the surface of the substrate on which the conductive part is disposed.

[0021] In one aspect, the step of forming a copper layer on the surface of the substrate on which the conductive portion is disposed includes:

[0022] A conductive seed layer is deposited on the surface of the substrate;

[0023] The copper layer is formed by electroplating based on the conductive seed layer.

[0024] In addition, to solve the above problems, this application also provides a battery, the battery including a positive terminal and a negative terminal, the negative terminal including the composite copper foil as described above.

[0025] In this application's technical solution, a substrate is used as a base, and grooves are formed on the surface of the substrate, with conductive parts disposed within the grooves. A copper layer covers the surface of the substrate, and when the copper layer transmits current, the current can also pass through the conductive parts. At the location of the grooves, the cross-sectional area of ​​the conductor through which the current flows increases, and the resistance decreases, thereby reducing heat generation in the composite copper foil, thus reducing overheating inside the battery and ensuring battery safety.

[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 1This is a schematic diagram of the composite copper foil structure in the first embodiment of this application.

[0029] Figure 2 This is a schematic diagram of the groove structure in the first embodiment of this application.

[0030] Figure 3 This is a schematic diagram of the structure in this application where the bottom surface of the groove is arc-shaped.

[0031] Figure 4 This is a schematic diagram of the structure in this application where the bottom surface of the groove is triangular.

[0032] Figure 5 This is a schematic diagram of the groove extending along the length of the substrate in this application.

[0033] Figure 6 This is a schematic diagram of the groove extending along the width direction of the substrate in this application.

[0034] Figure 7 This is a schematic diagram of the structure in this application where the grooves are uniformly arranged on the surface of the substrate.

[0035] Figure 8 This is a schematic diagram of the arrangement of grooves in the middle and edges of the substrate surface in this application.

[0036] Figure 9 This is a schematic diagram of the arrangement of grooves on two surfaces of the substrate in this application.

[0037] Figure 10 This is a flowchart illustrating the steps of the method for manufacturing the composite copper foil according to the second embodiment of this application.

[0038] Figure 11 This is a schematic flowchart of steps S410 and S420 of the method for manufacturing composite copper foil according to the second embodiment of this application.

[0039] The annotations in the attached figures are explained as follows:

[0040] 110. Substrate; 120. Conductive part; 130. Copper layer; 140. Conductive seed layer;

[0041] 101. First surface; 102. Second surface; 111. Groove; 111a. First groove; 111b. Second groove; 112. Channel. Detailed Implementation

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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.

[0046] The preferred embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0047] Example 1

[0048] See Figure 1 As shown, the composite copper foil in this application includes a substrate 110, a conductive portion 120, and a copper layer 130. The substrate 110 is made of a polymer material. The substrate 110 serves as the basic structure, and the conductive portion 120 and the copper layer 130 are sequentially disposed on the surface of the substrate 110. The substrate 110 serves as the basic structure, supporting the placement of the conductive portion 120 and the copper layer 130.

[0049] The surface of the substrate 110 is provided with grooves 111. These grooves 111 can be formed by laser etching or simultaneously during the formation of the substrate 110. For example, during the curing of the substrate 110, a raised mold is used to imprint grooves onto the surface, forming the grooves 111 after curing. Laser etching primarily involves a laser beam acting on the surface of the substrate 110, causing the chemical bonds in the substrate 110 material to break under photoelectric or photothermal effects, completing combustion or evaporation before carbonization. The thickness of the substrate 110 is typically between 3µm and 8µm, for example, 3µm, 4µm, 5µm, 6µm, 7µm, or 8µm.

[0050] The substrate 110 can be made of PET (polyethylene terephthalate), a milky white or light yellow, highly crystalline polymer with a smooth and glossy surface. It exhibits good creep resistance, fatigue resistance, abrasion resistance, and dimensional stability, with low wear and high hardness, and stable toughness; it is also minimally affected by temperature. It is non-toxic, weather-resistant, has good chemical stability, low water absorption, and is resistant to weak acids and organic solvents.

[0051] The substrate 110 can also be made of PP (Polypropylene), which is a high-performance thermoplastic synthetic resin. It is a colorless, semi-transparent, lightweight, general-purpose thermoplastic plastic with chemical resistance, heat resistance, electrical insulation, high mechanical strength, and good wear resistance.

[0052] The substrate 110 can also be PI (Polyimide), which is a highly reliable and flexible material that is also lightweight.

[0053] The conductive portion 120 is disposed within the groove 111. The conductive portion 120 can be disposed within the groove 111 by vapor deposition or by filling. The conductive portion 120 is disposed within the groove 111, and its surface is flush with the surface of the substrate 110. This allows the copper layer 130 to contact the conductive portion 120, facilitating the flow of current through it. If the conductive portion 120 protrudes from the groove 111, it can be removed by etching or polishing.

[0054] A copper layer 130 is disposed on the surface of the substrate 110 and covers the conductive portion 120. The copper layer 130 is mainly used as the negative electrode of the battery to transmit current. By using the substrate 110 as the basic structure and disposing of the copper layer 130 on the surface of the substrate 110, the copper layer 130 can directly contact the conductive portion 120, or indirectly contact the conductive portion 120 through other components. In this way, when the copper layer 130 transmits current, the current can flow through the conductive portion 120, which is equivalent to increasing the cross-sectional area of ​​the copper layer 130 at the groove 111.

[0055] This can be explained by the formula R = ρL / S, which shows that the cross-sectional area S is inversely proportional to the resistance R. Here, L is the length of the copper layer (130mm), ρ is the resistivity, and the resistance R decreases as the cross-sectional area S increases. According to Joule's law, Q = I... 2 Given Rt, Q represents heat, I represents current, and t represents time. When time t and current I are constant, the heat Q is directly proportional to the resistance R. As the resistance R decreases, the amount of heat generated also decreases.

[0056] In this embodiment, a groove 111 is formed on the surface of a substrate 110, and a conductive portion 120 is disposed within the groove 111. A copper layer 130 covers the surface of the substrate 110, and when the copper layer 130 transmits current, the current can also pass through the conductive portion 120. At the location of the groove 111, the cross-sectional area of ​​the conductor through which the current flows increases, and the resistance decreases, thereby reducing the heat generation in the composite copper foil, thus reducing the possibility of overheating inside the battery and ensuring the safety of battery use. This approach reduces heat generation inside the composite copper foil and avoids the use of excessive amounts of metallic copper.

[0057] See Figures 2 to 4 As shown, the shape of the groove 111 is not limited to square; it can be arc-shaped or triangular. When the composite copper foil is wound, the substrate 110 needs to be bent, and the substrate 110 is prone to tension. By setting the groove 111, the tension can be released at the groove 111 position, avoiding excessive deformation of the substrate 110, which could cause cracking or even separation of the substrate 110 and the copper layer 130.

[0058] See Figure 5 and Figure 6 As shown, the extension direction of the groove 111 can be along the length direction of the substrate 110 or along the width direction of the substrate 110. The X direction is the length direction, and the Y direction is the width direction. If the extension direction of the groove 111 is the X direction, the winding direction of the substrate 110 is along the Y direction. If the extension direction of the groove 111 is the Y direction, the winding direction of the substrate is along the X direction. In this way, the problem of disordered deformation during the winding process of the substrate 110 can be improved, and winding is easier. Moreover, during winding, winding tension is generated in the composite copper foil. By setting the groove 111, the tension can be released to a certain extent at the location of the groove 111, thereby alleviating the deformation problem.

[0059] See Figure 7 As shown, to more effectively ensure the safety of battery use, multiple grooves 111 are provided, and the multiple grooves 111 are arranged at equal intervals on the surface of the substrate 110. Moreover, a connecting channel 112 is provided between the grooves 111, and conductive metal can be placed at the position of the channel 112, so that the conductive parts 120 can also be connected, further improving the conductivity.

[0060] See Figure 8As shown, in addition to reducing overheating in the middle region of the composite copper foil, the grooves 111 can be arranged more densely in the middle of the substrate 110, while the grooves 111 can be arranged less densely at the edges of the substrate 110. The edges of the substrate 110 are closer to the outside environment, resulting in faster heat dissipation, thus reducing the number of conductive parts 120. In the middle region, the environment is relatively enclosed, leading to slower heat dissipation. Therefore, by providing more conductive parts 120, the resistance in the middle region is reduced, thereby reducing heat generation in the middle.

[0061] In addition, by setting more conductive parts 120 in the middle and fewer conductive parts 120 at the edge, the heat dissipation effect of the composite copper foil in the middle and at the edge can be balanced, reducing the situation of large local heat deformation of the composite copper foil and reducing the extrusion deformation between the internal structures of the composite copper foil.

[0062] In order to ensure that the conductive part 120 can perform its conductive effect, the conductive part 120 includes at least one of inorganic non-metallic conductive particles or metallic conductive particles.

[0063] This includes three scenarios: first, the conductive part 120 comprises inorganic non-metallic conductive particles; second, the conductive part 120 comprises metallic conductive particles; and third, the conductive part 120 comprises a mixture of inorganic non-metallic conductive particles and metallic conductive particles. By placing these conductive particles within the groove 111, the groove 111 can be filled as completely as possible.

[0064] Conductive adhesive can also be provided in the conductive part 120. Inorganic non-metallic conductive particles or metallic conductive particles are mixed with the conductive adhesive, and the corners of the groove 111 can be filled by the fluidity of the conductive adhesive.

[0065] Conductive adhesive is an adhesive that exhibits conductivity after curing or drying. It contains conductive particles that can connect various conductive materials, creating an electrical path between them. Specifically, before curing or drying, the conductive particles exist separately within the adhesive, without continuous contact, and are therefore in an insulating state. After curing or drying, the evaporation of the solvent and the solidification of the adhesive cause volume shrinkage, resulting in a stable and continuous state between the conductive particles, thus exhibiting conductivity. The conductive adhesive can extend around the groove 111, filling more areas of the groove 111.

[0066] In one aspect, inorganic non-metallic conductive particles include at least one of graphene or carbon nanotubes. Carbon nanotubes (CNTs) are coaxial, seamless tubular carbon materials with diameters on the nanometer scale, formed by one or more layers of graphite rolled up at a certain helical angle. Carbon nanotubes are generally classified into single-walled carbon nanotubes and multi-walled carbon nanotubes. Carbon nanotubes possess abundant electrical transport properties, good electrical and thermal conductivity, and stable chemical properties. Combining carbon nanotubes with polymer materials can effectively improve the physical properties of the host material.

[0067] Graphene is a type of carbon atom arranged in sp... 2 Graphene is a two-dimensional carbon nanomaterial with a hexagonal honeycomb lattice composed of hybrid orbitals. Its fundamental properties include high strength and flexibility, thermal and electrical conductivity, and optical properties. At room temperature, graphene's electron mobility exceeds 15000 cm⁻¹. 2 The resistivity is only about 10⁻⁶ Ωcm, lower than that of copper or silver. As one of the important applications of graphene, graphene transparent conductive films exhibit good conductivity, chemical stability and flexibility.

[0068] The conductive metallic particles include at least one of gold, silver, copper, iron, nickel, tin, or aluminum. Gold, silver, copper, iron, nickel, tin, and aluminum are all capable of conducting electricity. The properties of the conductive metallic particles are similar to those of the copper layer 130, while the properties of the inorganic non-metallic conductive particles are similar to those of the substrate 110. By mixing these two types of conductive particles, the material possesses both metallic and non-metallic properties. When this mixture is filled into the groove 111, it achieves good bonding with both the substrate 110 and the copper layer 130. At this point, the conductive part 120 has adhesive properties to both the substrate 110 and the copper layer 130, and with the help of the conductive adhesive, it effectively bonds the substrate 110 and the copper layer 130, improving their bonding strength.

[0069] Furthermore, when the conductive part 120 and the copper layer 130 are made of the same material, namely metallic copper, the bonding force between the substrate 110 and the copper layer 130 can be improved. Since the substrate 110 is a polymer material and the copper layer 130 is a metal, it is difficult for them to form an effective bond at their contact surface. Therefore, the contact area between the copper layer 130 and the substrate 110 can be increased by providing grooves 111. This improves the bonding effect and reduces separation between the copper layer 130 and the substrate 110.

[0070] When setting the conductive part 120, it can be formed by injection, in which conductive adhesive mixed with inorganic non-metallic conductive particles or metallic conductive particles is injected into the groove 111. Alternatively, it can be formed by vacuum magnetron sputtering, in which conductive particles are deposited in the groove 111. Furthermore, the conductive part 120 can also be formed by ultrasonic spraying (spraying a suspension of conductive particles), in which ultrasonic waves act on the suspended conductive particles, causing the particles to move towards the groove 111 and deposit there, thus forming the conductive part 120.

[0071] The copper layer 130 is relatively thick. To reduce damage to the substrate 110 caused by the high temperature and high-speed particles of magnetron sputtering, electroplating can be used when setting the copper layer 130. Specifically, the composite copper foil also includes a conductive seed layer 140, which is disposed between the conductive portion 120 and the copper layer 130. The material of the conductive seed layer 140 is the same as that of the copper layer 130. The conductive seed layer 140 can be set by vacuum magnetron sputtering. Because the conductive seed layer 140 is relatively thin, the substrate 110 is exposed to the magnetron sputtering environment for a short time, which will not cause significant damage to the substrate 110. The thickness of the conductive seed layer 140 is typically between 30 nm and 70 nm. The thickness of the conductive seed layer 140 can be 30nm, 31nm, 32nm, 33nm, 34nm, 35nm, 36nm, 37nm, 38nm, 39nm, 40nm, 41nm, 42nm, 43nm, 44nm, 45nm, 46nm, 47nm, 48nm, 49nm, 50nm, 51nm, 52nm, 53nm, 54nm, 55nm, 56nm, 57nm, 58nm, 59nm, 60nm, 61nm, 62nm, 63nm, 64nm, 65nm, 66nm, 67nm, 68nm, 69nm, or 70nm. The thickness of the copper layer 130 is between 1µm and 2µm, and can be 1µm, 1.1µm, 1.2µm, 1.3µm, 1.4µm, 1.5µm, 1.6µm, 1.7µm, 1.8µm, 1.9µm, or 2µm.

[0072] If the thickness of the conductive part 120 is D, then it satisfies: 0.1um ≤ D ≤ 0.5um. The thickness of the conductive part 120 can also be understood as the depth of the groove 111. The thickness of the conductive part 120 can be 0.1um, 0.2um, 0.3um, 0.4um, or 0.5um.

[0073] See Figure 9As shown, the substrate 110 has a first surface 101 and a second surface 102 disposed opposite to each other. The groove 111 on the first surface 101 is a first groove 111a, and the groove 111 on the second surface 102 is a second groove 111b. The first groove 111a and the second groove 111b are staggered. This staggered arrangement avoids placing grooves 111 in the same orthographic projection area on the surface of the substrate 110. If grooves 111 are placed in the same orthographic projection area, the substrate 110 may become too thin at that location. If the thickness is too thin, the tensile strength of the substrate 110 may decrease, and the composite copper foil may easily break.

[0074] Example 2

[0075] See Figure 10 As shown, this application also provides a method for manufacturing a composite copper foil, the method comprising:

[0076] Step S10: Provide a substrate 110. The substrate 110 is usually made of polymer material. The substrate 110 serves as the basic structure to support the conductive part 120 and the copper layer 130.

[0077] In step S20, a groove 111 is formed on the surface of the substrate 110; the groove 111 is etched on the surface of the substrate 110 by laser etching. The laser can be controlled to move along a preset path on the surface of the substrate 110, thereby etching the groove 111 on the surface of the substrate 110. The depth of the groove 111 can be controlled by adjusting the laser power and etching time.

[0078] In step S30, the surface of the substrate 110 is masked, exposing the groove 111. Conductive particles are deposited within the groove 111 to form a conductive portion 120. A mask is used to cover the surface of the substrate 110 and expose the groove 111. The mask has openings corresponding to the groove 111. There are various methods for depositing the conductive portion 120, such as vapor deposition. Alternatively, conductive adhesive injection or ultrasonic spraying can be used. Magnetron sputtering is a type of physical vapor deposition (PVD). Magnetron sputtering bombards conductive particles from a target and deposits them into the groove 111. Magnetron sputtering can be used to prepare various materials such as metals, semiconductors, and insulators, and has advantages such as simple equipment, easy control, large coating area, and strong adhesion. Magnetron sputtering increases the sputtering rate by introducing a magnetic field onto the target cathode surface and using the magnetic field to confine charged particles.

[0079] In step S40, a copper layer 130 is formed on the surface of the substrate 110 on which the conductive part 120 is formed.

[0080] In this embodiment, a substrate 110 is used as the basic structure. Grooves 111 are formed on the surface of the substrate 110 by laser etching, and conductive particles are placed within the grooves 111 to form a conductive portion 120. A copper layer 130 covers the surface of the substrate 110. When the copper layer 130 transmits current, the current can also pass through the conductive portion 120. At the location of the grooves 111, the cross-sectional area of ​​the conductor through which the current flows increases, and the resistance decreases, thereby reducing heat generation in the composite copper foil, thus reducing overheating inside the battery and ensuring battery safety.

[0081] See Figure 11 As shown, the step of forming a copper layer 130 on the surface of the substrate 110 where the conductive portion 120 is provided includes:

[0082] In step S410, a conductive seed layer 140 is deposited on the surface of the substrate 110, covering the conductive portion 120. The conductive seed layer 140 can be deposited by physical vapor deposition, such as magnetron sputtering. At this time, the mask is removed, exposing both the surface of the substrate 110 and the conductive portion 120 to the magnetron sputtering environment. Thus, under the influence of a magnetic field, copper ions gradually deposit a conductive seed layer 140 on the surface of the substrate 110.

[0083] In step S420, a copper layer 130 is formed by electroplating based on the conductive seed layer 140. The substrate 110 on which the conductive seed layer 140 is disposed is immersed in a solution containing copper ions. Electroplating is performed by using the conductive seed layer 140 as a cathode, causing copper ions to precipitate on the surface of the conductive seed layer 140 and cover it. The solution containing copper ions includes a copper sulfate solution and may also be a copper fluoroborate solution.

[0084] Example 3

[0085] This application also provides a battery, which includes a positive terminal and a negative terminal, wherein the negative terminal includes a composite copper foil as described above.

[0086] The specific implementation method and beneficial effects of the battery are described in the above-mentioned composite copper foil examples, and will not be repeated here.

[0087] 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 manufacturing composite copper foil, characterized in that, The method for manufacturing the composite copper foil includes: Provide base materials; Grooves are provided on the upper and lower surfaces of the substrate; The upper and lower surfaces of the substrate are covered and the groove is exposed, and conductive particles are deposited in the groove to form a conductive portion; A copper layer is provided on the entire upper and lower surfaces of the substrate on which the conductive part is disposed; The step of forming a copper layer on the surface of the substrate on which the conductive portion is disposed includes: A conductive seed layer is deposited on the surface of the substrate; The copper layer is formed by electroplating based on the conductive seed layer.

2. A composite copper foil, characterized in that, The composite copper foil is manufactured using the method described in claim 1, and the composite copper foil comprises: The substrate has grooves on both its upper and lower surfaces; A conductive part is disposed within the groove; A copper layer is disposed on the entire upper and lower surfaces of the substrate and covers the conductive portion.

3. The composite copper foil according to claim 2, characterized in that, The groove is provided in multiple ways, and the multiple grooves are arranged at equal intervals on the surface of the substrate.

4. The composite copper foil according to claim 2, characterized in that, The conductive part includes at least one of inorganic non-metallic conductive particles or metallic conductive particles.

5. The composite copper foil according to claim 4, characterized in that, The inorganic non-metallic conductive particles include at least one of graphene or carbon nanotubes; The conductive metal particles include at least one of gold, silver, copper, iron, nickel, tin, or aluminum.

6. The composite copper foil according to claim 2, characterized in that, The composite copper foil further includes a conductive seed layer, which is disposed between the conductive portion and the copper layer, and the conductive seed layer is made of the same material as the copper layer.

7. The composite copper foil according to claim 2, characterized in that, If the thickness of the conductive part is D, then the following condition must be met: 0.1um ≤ D ≤ 0.5um.

8. The composite copper foil according to any one of claims 2 to 7, characterized in that, The substrate has a first surface and a second surface disposed opposite to each other. The groove on the first surface is a first groove, and the groove on the second surface is a second groove. The first groove and the second groove are interleaved.

9. A battery, characterized in that, The battery includes a positive terminal and a negative terminal, wherein the negative terminal includes a composite copper foil as described in any one of claims 2-8.

Images