A winding core for electrolytic copper foil

Abstract

The utility model discloses a kind of winding tube core for electrolytic copper foil, including tube core body, the through hole being axially provided in the middle part of tube core body, the tube core body is formed by high-strength glass fiber winding solidification with resin infiltration.The utility model can solve the high cost of directly replacing high-strength material tube core, and the method of directly thickening tube core can cause the high cost problem of upgrading and replacing all tooling, procedures and hardware software used in the production process of copper foil in downstream battery production.

Description

Technical Field

[0001] This utility model relates to the field of electrolytic copper foil manufacturing technology, specifically a winding core for electrolytic copper foil. Background Technology

[0002] Electrolytic copper foil, a fundamental material in the electronic circuit and lithium battery industries, significantly impacts the performance of electronic products and lithium batteries. During its production, the electrolytically generated copper foil is slit and then wound onto a die. When existing FRP (fiberglass reinforced plastic) dies lack sufficient strength, the die deforms to varying degrees after the copper foil is wound. When this deformation reaches a certain level, it leads to compression deformation and wrinkling of the copper foil. Current methods involve replacing FRP with other high-strength die materials or directly increasing the thickness of the FRP die to improve strength. However, directly replacing the die with a high-strength material is costly, while directly increasing the die thickness would require upgrading all hardware and software used in copper foil production and downstream battery manufacturing, impacting a wide range of applications and facing significant resistance from customers during widespread adoption. Therefore, a die design is needed that can improve die strength without altering the existing equipment structure. Utility Model Content

[0003] This invention provides a winding core for electrolytic copper foil, which can solve the problems of high cost of directly replacing the core with a high-strength material, and the high cost of upgrading and replacing all the hardware and software such as tooling and programs used in copper foil production and downstream battery production.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a winding core for electrolytic copper foil, comprising a core body, wherein a through hole is axially provided in the middle of the core body, and the core body is formed by winding and curing high-strength glass fiber impregnated with resin.

[0005] Preferably, the two ends of the core body are provided with grooves in the circumferential direction to form steps.

[0006] Preferably, the high-strength glass fiber is wound obliquely at an angle of 0-90°.

[0007] Preferably, the groove is formed by machining.

[0008] Compared with the prior art, the beneficial effects of this utility model are:

[0009] Formed by winding and curing high-strength glass fiber, it not only has high strength, but also allows the core thickness to be flexibly adjusted according to the winding weight, in order to further improve the core's resistance to deformation. The stepped structure at both ends of the core can enhance the adaptability of the thickened core, reduce the program and equipment upgrades caused by the iterative thickening of the core, and the manufacturing process is simple, without the need to upgrade or replace all existing tooling, programs and other hardware and software; moreover, it is made of non-metallic glass fiber mixed resin material, avoiding the introduction of metal elements when the copper foil is wound. Attached Figure Description

[0010] Figure 1 This is a front sectional view of the structure of this utility model.

[0011] Figure label:

[0012] 1. Core body, 2. Groove, 3. Through hole. Detailed Implementation

[0013] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0014] This invention addresses the high cost of directly replacing the die with a high-strength material, and the high cost of directly thickening the die, which necessitates upgrading and replacing all hardware and software, including tooling and processes, used in copper foil production and downstream battery manufacturing. Figure 1 As shown, the following technical solution is provided: a winding core for electrolytic copper foil, comprising a core body 1, wherein a through hole 3 is axially provided in the middle of the core body 1, and the core body 1 is formed by winding and curing high-strength glass fiber impregnated with resin.

[0015] As one specific embodiment of this example, such as Figure 1 As shown, the two ends of the core body 1 are provided with grooves 2 around the circumference to form steps, and the grooves 2 are formed by machining.

[0016] By creating steps at both ends of the core tube body, with a step width of 5-10mm and a depth of 2-5mm, the mating diameter at both ends of the core tube is made consistent with that of traditional FRP core tubes (e.g., φ76mm). The thickened section in the middle (outer diameter can be increased to φ80-85mm) does not affect the fit with the chuck and guide device of existing equipment, allowing for direct replacement without adjusting equipment parameters. Calculations show that after adopting this invention, manufacturing enterprises do not need to modify their equipment, saving 300,000-600,000 yuan in modification costs per production line. Downstream enterprises also do not need to adjust their unwinding equipment, significantly reducing the upgrading costs of the industrial chain and reducing promotion resistance by more than 80%.

[0017] This embodiment uses a non-metallic high-strength glass fiber and resin composite material with high purity (metal impurity content ≤5ppm). No metal debris falls off during the winding process, and the metal impurity content on the copper foil surface can be controlled below 10ppm. Downstream lithium battery companies using this copper foil have seen their battery capacity retention rate increase to over 85% after 1000 cycles, and the micro-short circuit incidence rate decrease by 90%, significantly improving the performance and safety of lithium batteries. Simultaneously, the glass fiber and resin exhibit excellent chemical stability, showing no corrosion or aging after 6 months of storage in a humid environment (60-80% humidity), and the surface smoothness of the die remains below Ra0.8μm, preventing scratches on the copper foil caused by a rough die surface.

[0018] As one manufacturing process in this embodiment:

[0019] Step a, winding. After being impregnated with resin and curing agent, high-strength glass fiber is wound at a specific angle between 0-90° under the tension of a winding machine. The glass fiber filaments mixed with resin and curing agent are wound onto a steel mold core, and the outer diameter is wound to the specified outer diameter value.

[0020] Specifically, high-strength glass fibers with a tensile strength ≥3000MPa (such as E-CR glass fibers) can be selected, impregnated with a mixture of epoxy resin (epoxy value 0.51eq / 100g) and curing agent (amine curing agent, added at 10% of the resin mass) (viscosity 200-300cP). The fibers are wound at a 45° angle on a winding machine, with the winding tension controlled at 50-80N (excessive tension will cause fiber breakage, while insufficient tension will result in loose bonding). The number of winding layers is 8-10, ensuring the outer diameter of the middle portion of the core reaches φ80mm.

[0021] Step b, Curing Treatment. The core blank carrying the steel mandrel, wrapped with glass fiber filaments, is placed in an oven for baking at 120℃ for 16 hours. Specifically, the core blank is placed in the oven and cured using a gradient temperature increase: 60℃ for 2 hours (preliminary curing) → 80℃ for 4 hours (geling) → 120℃ for 10 hours (complete curing), for a total time of 16 hours. This process avoids the formation of bubbles in the resin due to rapid heating (bubble rate ≤0.1%), ensuring a core density ≥1.8 g / cm³.

[0022] Step c, demolding. The cured steel strip core is placed on a demolding machine, which separates the steel core from the molded core. Specifically, a hydraulic demolding machine is used to separate the steel core from the core with an axial pressure of 5-10 MPa. The core does not crack during the demolding process.

[0023] Step d, surface machining. Perform turning and grinding according to the dimensions specified in the drawing to form steps. Specifically, use a precision lathe to turn the groove to form a step (8mm wide, 3mm deep), and grind the outer diameter to Ra0.4μm to ensure the smoothness of the mating surface with the equipment. The outer diameter at both ends of the step is kept at φ76mm.

[0024] Step e, core cleaning. Rinse the finished core with running water and wipe the inner and outer surfaces of the core clean. Specifically, you can rinse with deionized water (conductivity ≤10μS / cm), ultrasonically clean for 10 minutes to remove residual debris, and then dry in a 60℃ drying oven for 2 hours.

[0025] Step f: Drying and Packaging. Place the cleaned core tubes in a drying oven at 40℃ for 6 hours. After drying, package them according to the specified packaging requirements.

[0026] When this die is applied to the winding process of electrolytic copper foil, the surface of the wound copper foil is smooth, without wrinkles or scratches, under the conditions of a winding speed of 100 meters / minute and a tension of 500 Newtons, and the die has a service life of more than 20 cycles.

[0027] As another manufacturing process in this embodiment:

[0028] Compared with the manufacturing process described above, the main differences are as follows:

[0029] Step a (winding): First, wind 4 layers at a 60° angle, then wind 6 layers at a 30° angle, increasing the fiber volume content to 65%, increasing the outer diameter of the middle part to φ85mm, and keeping the diameter of the stepped ends at φ76mm.

[0030] Step b (curing treatment): Heat to 130℃ and keep warm for 18 hours to ensure that the thick-walled part (wall thickness 8mm) is completely cured.

[0031] Under the conditions of a winding speed of 100 m / min and a tension of 800 N, after winding 800 kg of copper foil, the radial deformation of the core is 0.3 mm, the axial bending is 0.4 mm, the flatness (warping) of the copper foil is ≤2 mm / m, and the service life is more than 30 times.

[0032] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0033] Furthermore, in this utility model, descriptions involving terms such as "primary," "secondary," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "primary" or "secondary" may explicitly or implicitly include at least one of those features. In the description of this utility model, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly and specifically defined.

[0034] In this utility model, unless otherwise explicitly specified and limited, the terms "connection," "fixing," etc., should be interpreted broadly. For example, "fixing" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0035] Furthermore, the technical solutions of the various embodiments of this utility model can be combined with each other, but only if they are based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

Claims

1. A winding core for electrolytic copper foil, comprising a core body (1), characterized in that, The core body (1) has a through hole (3) axially arranged in the middle. The core body (1) is formed by winding and curing high-strength glass fiber impregnated with resin. The two ends of the core body (1) are provided with grooves (2) around the circumference to form steps.

2. The winding core for electrolytic copper foil according to claim 1, characterized in that: The high-strength glass fiber is wound obliquely at an angle of 0-30°.

3. The winding core for electrolytic copper foil according to claim 1, characterized in that: The groove (2) is formed by machining.

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