Composite current collector and evaporation device

Abstract

The utility model discloses a composite current collector and an evaporation device, and belongs to the technical field of current collectors, and the composite current collector comprises a supporting layer which comprises a base film made of a high polymer material; the first holes are formed in the surface layer of the supporting layer; the second holes are communicated with the corresponding first holes, and the maximum cross section width D of the second holes is larger than the cross section width d of the communication positions of the first holes and the second holes; and the conductive layer is formed on the surfaces of the supporting layer, the first hole and the second hole. Through the arrangement of the first hole and the second hole, the specific surface area of the surface layer of the base film is increased, and the roughness is increased, so that the adhesiveness with a conducting layer can be improved, and meanwhile, the anchoring performance of the conducting layer can be further improved due to the enlarged size of the second hole.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of current collector, especially to a composite current collector. BACKGROUND

[0002] In the secondary battery, the current collector is needed, which is the part of current convergence, and its material is generally aluminum foil or copper foil; in the prior art, the composite current collector is proposed, that is, it includes a high polymer support layer and a metal layer arranged on both sides of the support layer, which can improve the safety of the subsequent battery, and compared with the metal foil current collector, the composite structure can also reduce the weight of the current collector and improve the energy density of the lithium ion battery.

[0003] However, due to the difference between the conductive layer and the support layer material of the polymer, and generally based on the water plating method of vapor deposition, the bonding force of the conductive layer and the support layer is relatively poor, and at the same time, due to the high flatness of the conductive layer, the bonding force of the subsequent active material coating is also relatively poor.

[0004] In the prior art, the support layer (base film) is generally treated by plasma corona treatment to increase the roughness of its surface; or the roughness of the conductive layer is increased by etching on the surface of the conductive layer to increase the bonding force with the active material. SUMMARY

[0005] At present, the ability to improve the conductive layer of the current collector and the bonding force between the conductive layer and the electrode material is limited.

[0006] The utility model at least aims at solving one of the technical problems in the related art to some extent. To this end, one object of the utility model is to provide a composite current collector, which forms a connected hole structure with different sizes on the surface layer of the support layer to increase the adhesion of the conductive layer and the subsequent active material.

[0007] Another object of the present application is to provide a device for processing the above-mentioned current collector.

[0008] The technical scheme of the utility model is as follows:

[0009] In the first aspect, the utility model discloses a composite current collector, which comprises:

[0010] The support layer includes a base film of high molecular material;

[0011] A plurality of first holes are formed in the surface layer of the support layer; and

[0012] The second hole is communicated with the corresponding first hole, and the maximum cross-sectional width D of the second hole is greater than the cross-sectional width d of the communication place of the first hole and the second hole;

[0013] The conductive layer is formed on the surface of the support layer and the first hole and the second hole.

[0014] According to the above technical scheme, the first hole and the second hole are arranged, the specific surface area of the base film surface layer is increased, the roughness is increased, and therefore the adhesion with the conductive layer can be improved. Meanwhile, the size of the second hole is increased, the anchoring performance of the conductive layer is further increased, the adhesion of the conductive layer is further increased, and when the active material is coated subsequently, the active material can be filled and embedded into the pores, and the bonding force with the active material can be further increased.

[0015] Further, the maximum width of the first hole is 0.1-2.0 mm.

[0016] Further, the vertical distance of the inward overdeepening of the first hole is not more than 0.1 mm.

[0017] Further, the interval distance between adjacent first holes is 5-20 mm.

[0018] According to the above technical scheme, the size of the first hole is controlled to avoid affecting the strength of the film.

[0019] Further, the maximum width of the second hole is 1.05-1.5 times the width of the communication part with the first hole.

[0020] Further, the first hole is in the form of an enlarged hole.

[0021] According to the above technical scheme, it is beneficial to deposit in the inner region of the hole, and it is also beneficial to deposit in the second hole.

[0022] Further, a protective layer is formed on the surface of the support layer and the part of the first hole close to the outer side of the support layer.

[0023] According to the above technical scheme, the influence on the non-etching area can be reduced, and it is beneficial to form the second hole in the first hole.

[0024] Further, the support layer is arranged in a composite structure, the protective layer is arranged as a corrosion-resistant polymer layer compounded on the surface layer of the support layer, and the depth of the first hole is greater than the thickness of the corrosion-resistant polymer layer.

[0025] According to the above technical scheme, etching processing can be conveniently performed to obtain the required hole structure.

[0026] In a second aspect, the application discloses a vapor deposition device for processing the above-mentioned composite current collector, comprising:

[0027] A vapor deposition roller is arranged in the vacuum chamber and corresponds to the vapor deposition area.

[0028] The support layer is arranged to be attached to the vapor deposition roller, and the included angle α between the support layer and the vapor deposition roller is not less than 30°.

[0029] Based on the above technical scheme, the hole structure in the support layer after being opened can be expanded, the shielding is reduced, and the metal vapor during evaporation can enter the hole.

[0030] Further, the wrap angle a of the support layer and the evaporation roller is not less than 45 degrees. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, illustrate the present application, and are used to explain the present application together with embodiments of the present application, and do not constitute a limitation on the present application. In the drawings:

[0032] Figure 1 is a sectional view of the current collector with the first hole structure;

[0033] Figure 2 is a sectional view of the current collector with the second hole structure;

[0034] Figure 3 is a structure schematic view of the evaporation roller part in the evaporation device;

[0035] Figure 4 is a sectional view of the composite support layer with the protective layer.

[0036] In the figure, the horizontal direction represents the longitudinal direction, and the vertical direction represents the thickness direction.

[0037] In the figure:

[0038] 1-support layer; 21-first hole; 22-second hole; 3-conductive layer; 4-evaporation roller; 41-guide roller; 5-protective layer. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be described clearly and completely below by combining the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, but not all the embodiments.

[0040] Examples of the described embodiments are shown in the drawings, in which the same or similar reference signs represent the same or similar elements or elements with the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application, but cannot be understood as a limitation on the present application.

[0041] With reference to Figure 1 and Figure 2 The present application discloses a composite current collector, comprising:

[0042] The support layer 1 comprises a base film of a high polymer material; the support layer material is a high polymer material commonly used for composite current collectors, such as PP, PET, PI, etc., and the thickness thereof is preferably set to 3-500 μm, and more preferably to 4-20 μm;

[0043] The support layer 1 has a plurality of first holes 21 formed on the surface thereof, and a plurality of second holes 22 in communication with the first holes 21, wherein the maximum cross-sectional width D of the second holes 22 is greater than the cross-sectional width d of the communication part between the first holes 21 and the second holes 22.

[0044] The conductive layer 3 is formed on the surface of the support layer 1 and the first holes 21 and the second holes 22.

[0045] The first holes 21 and the second holes 22 increase the specific surface area of the surface of the base film, increase the roughness, and thus improve the adhesion of the conductive layer; meanwhile, the increased size of the second holes 22 further improves the anchoring performance of the conductive layer, further improves the adhesion of the conductive layer, and is also beneficial to the subsequent coating of the active material, filling and embedding into the pores, and further increasing the bonding force with the active material.

[0046] It should be noted that the second holes only represent the hole structure in communication with the first holes, and do not specifically refer to the number of holes, and thus a larger group of hole structures in communication with the first holes should also be covered by the protection scope of the present application.

[0047] Referring to Figure 1 In some embodiments of the present application, the first holes 21 are blind holes, and the whole thereof is in the shape of a flared portion, similar to a V-shaped or stepped shape with the cross-sectional size decreasing inwardly, which can be formed based on needle roller puncture or die pressing; in order to control the hole depth, a certain thickness of a pad material can be arranged between the puncture device or the die pressing device and the support layer for controlling the puncture / die pressing depth; of course, the first holes 21 can also be formed by etching (such as laser etching or chemical etching).

[0048] The size of the first holes 21 is not specifically limited, but considering the subsequent formation of the conductive layer, the maximum size of the first holes 21 should be not less than 0.1 mm, and the size of the first holes should not be too large, preferably not more than 2 mm, so as to avoid affecting the strength of the film; meanwhile, the vertical distance of the second holes 22 inwardly beyond the depth is within 0.1 mm, and the depth is too deep, which is not easy to deposit the conductive layer, and affects the strength. The density of the first holes 21 can be set as required, such as the interval distance between adjacent first holes 21 being 5-20 mm.

[0049] For the second hole 22, since its relative communication has a larger aperture size, it can be further reamed on the basis of the first hole 21 when prepared; specifically, after the first hole is formed based on laser etching, a laser with a smaller spot diameter can be selected, and the angle of the laser head of the laser is deflected, during which appropriate tension is maintained, so that the first hole 21 sidewall can be fully expanded, giving the space for the spot, and the second hole 22 extending towards the unetched area of the support layer 1 can be formed on the first hole 21 sidewall; the maximum width of the second hole 22 is 1.05-1.5 times the width of the communication with the first hole 21;

[0050] Of course, the second hole 22 can also be obtained based on chemical etching, such as coating the etching liquid after etching the liquid, filling part of the etching liquid in the first hole 21, and then etching at a suitable temperature, preferably under negative pressure; Specifically, the commonly used acid / alkali etching, and the selection of acid / alkali etching agent with appropriate strength, such as for PET-based film, can be etched by alkali etching, and after etching, the film surface is cleaned and dried for further next step.

[0051] Further referring to Figure 3 In order to form the conductive layer 3 in the formed hole 21, 22, a vapor deposition device is also disclosed, which comprises a vapor deposition roller 4 arranged in a vacuum chamber, the vapor deposition roller 4 is arranged corresponding to the vapor deposition area, and the support layer 1 is arranged through the guide roller 41, and the wrap angle α of the support layer 1 and the vapor deposition roller 4 is not less than 30°, preferably not less than 45°; to spread the hole 21 / 22 in the longitudinal direction (length direction), which is beneficial to form the conductive layer 3 in the hole, because the size of the second hole 22 is relatively larger, although there may be a blind area of the metal vapor deposition near the inner wall top of the hole communication part, but the metal vapor has flowability, and because the support layer has a relatively large wrap angle on the vapor deposition roller, the space in the hole can be increased to a certain extent, and the shielding of the hole is reduced; with the second hole 22 sidewall and bottom can deposit and gradually thicken the conductive layer.

[0052] Of course, the vapor deposition device also includes a vacuum system, a vapor deposition system and related transmission system, which has the same structure as the traditional vapor deposition device, and will not be repeated here.

[0053] In addition, as Figure 4 Considering that when etching a single-layer base film, there may be a strong etching effect on the entire support layer base film, which may affect the overall strength of the base film. Therefore, a protective layer 5 is formed on the surface of the support layer 1 and part of the first hole 21 area to reduce the influence on the non-etched area;

[0054] The protective layer 5 can be based on other corrosion-resistant polymer film materials such as polypropylene, polyimide, etc. compounded on the surface layer of the support layer 1, that is, a composite support layer structure is formed; the protective layer can be formed by heat compounding or flow casting; after the first hole 21 is further formed, the first hole 21 extends into the base film of the support layer 1, and then the etching liquid is coated; due to the difference in corrosion resistance, the material of the support layer 1 is etched to form the second hole 22.

[0055] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings or conventional expressions in the prior art, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0056] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of existence of A, existence of A and B, and existence of B. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0057] In the present application, "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0058] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and any skilled person in the art can make equivalent replacement or change according to the technical scheme and the inventive concept of the present application within the technical range disclosed by the present application, which should be covered within the protection scope of the present application.

Claims

1. A composite current collector, characterized by, The application relates to a support layer, which comprises a base film of a high molecular material, a plurality of first holes formed in the surface layer of the support layer, and a plurality of second holes in communication with the corresponding first holes, wherein the maximum cross-sectional width D of the second holes is greater than the cross-sectional width d of the first holes at the position where the first holes are in communication with the second holes. The maximum width of the first holes is 0.1-2.0 mm. The vertical distance of the first holes from the inner side of the support layer is not more than 0.1 mm. The interval distance between the adjacent first holes is 5-20 mm. The maximum width of the second holes is 1.05-1.5 times the width of the first holes at the position where the first holes are in communication with the second holes. The first holes are in the form of counterbores.

2. The composite current collector of claim 1, wherein A protective layer is formed on the surface of the support layer and the part of the first holes close to the outer side of the support layer.

3. The composite current collector of claim 1, wherein The support layer is in the form of a composite structure, the protective layer is a corrosion-resistant polymer layer compounded on the surface layer of the support layer, and the depth of the first holes is greater than the thickness of the corrosion-resistant polymer layer.

4. The composite current collector of claim 1, wherein The application further relates to a vacuum evaporation device, which comprises an evaporation roller arranged in a vacuum chamber and corresponding to an evaporation area, and a support layer arranged in close contact with the evaporation roller, wherein the included angle alpha between the support layer and the evaporation roller is not less than 30 degrees.

5. The composite current collector of claim 1, wherein The included angle alpha between the support layer and the evaporation roller is not less than 45 degrees.

6. The composite current collector of any one of claims 1-5, wherein, ​ 7. The composite current collector of claim 6, wherein ​ 8. The composite current collector of claim 7, wherein ​ 9. An evaporation apparatus for processing a composite current collector according to any one of claims 1 to 5, 7, and 8, characterized by ​ ​ ​ 10. The evaporation apparatus according to claim 9, wherein ​

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