Ultrathin composite current collector and preparation equipment

Abstract

The utility model provides an ultra-thin composite current collector and preparation equipment, the ultra-thin composite current collector comprises a current collector main body, the current collector main body comprises a polymer film layer and a first coating, the first coating is arranged on the polymer film layer, and the polymer film layer is arranged on the first coating. The current collector body is provided with a reduction area used for reducing the thickness of the polymer film layer on the side where the polymer film layer is located, a second coating is arranged on the current collector body, the first coating is located on the upper surface of the polymer film layer, and the second coating is located on the lower surface of the polymer film layer. According to the composite current collector, the thickness of the polymer film layer can be greatly reduced, the weight of the composite current collector can be reduced, the energy density of the battery can be improved, meanwhile, the polymer film layer is thicker when the first coating is formed, and high-temperature particles of materials forming the first coating cannot burn through the polymer film layer. And when the second coating is formed, high-temperature particles forming the second coating do not penetrate through the polymer film layer and the first coating, so that the whole composite current collector is ensured not to be burnt through.

Description

Technical Field

[0001] This utility model relates to the field of current collectors, and in particular to an ultra-thin composite current collector and its preparation equipment. Background Technology

[0002] Composite current collectors typically possess excellent electrical conductivity and mechanical strength. They are responsible for carrying the active materials of the positive and negative electrodes and collecting the current generated by electrochemical reactions for external output. Simultaneously, the current collector effectively disperses and transfers heat generated within the battery cell, improving heat dissipation and helping to maintain temperature stability. The physicochemical properties of the current collector significantly influence the performance of lithium-ion batteries. Key physical properties of current collectors include thickness, thickness uniformity, areal density, surface roughness, tensile strength, elongation, and porosity, while chemical properties include oxidation resistance, corrosion resistance, and heat resistance. Composite current collectors have a "sandwich" structure. When punctured by a sharp object, the sandwich film layer encapsulates the object, preventing contact between the positive and negative electrodes and thus preventing short circuits and combustion. However, in the current manufacturing process, due to the thinness of the composite current collector, the sandwich film layer is easily burned through under the impact of high-temperature particles, forming voids and causing quality defects. Therefore, existing technology requires further improvement. Utility Model Content

[0003] In view of the shortcomings of the prior art, the purpose of this utility model is to provide an ultra-thin composite current collector and its preparation equipment.

[0004] To solve the above technical problems, the present invention adopts the following technical solution:

[0005] This utility model provides an ultra-thin composite current collector, including a current collector body. The current collector body includes a polymer film layer and a first coating layer. The first coating layer is disposed on the polymer film layer. The current collector body has a reduction area on the side where the polymer film layer is located for reducing the thickness of the polymer film layer. The current collector body has a second coating layer. The first coating layer is located on the side where the upper surface of the polymer film layer is located, and the second coating layer is located on the side where the lower surface of the polymer film layer is located.

[0006] In a preferred embodiment, the thickness of the polymer film layer in the ultrathin composite current collector is 6µm to 20µm.

[0007] In a preferred embodiment, the thickness of the first coating of the ultra-thin composite current collector is 500nm to 1500nm, and the thickness of the second coating is 500nm to 1500nm.

[0008] In a preferred embodiment, the ultra-thin composite current collector has a second coating disposed on the outside of the first coating and on the opposite side of the first coating. A transition layer is also disposed between the first coating and the polymer film layer, and a transition layer is also disposed between the second coating and the polymer film layer.

[0009] In a preferred embodiment, the ultra-thin composite current collector further includes an electrode tab, the thickness of the polymer film layer in the cut-off region at the location of the electrode tab is zero, and the second coating is disposed on the side of the polymer film layer away from the first coating.

[0010] In a preferred embodiment, the length of the tab portion of the ultrathin composite current collector is 3µm-50µm.

[0011] In a preferred embodiment, the ultra-thin composite current collector further includes an adapter plate, the substrate of which is overlapped and connected to the outer side of the second coating, and the protruding part of the adapter plate is connected to the electrode tab.

[0012] In a preferred embodiment, the ultra-thin composite current collector has a bonding area on the side where the cut-off region is located, and the second coating fills the bonding area.

[0013] This utility model also provides an ultra-thin composite current collector preparation device, including a vacuum chamber. An evaporation source and a winding mechanism for unfolding a polymer film are provided in the vacuum chamber. The winding mechanism includes an unwinding device, a first cooling main drum, a second cooling main drum, and a winding device. The polymer film is unwound from the unwinding device, passes through the first and second cooling main drums, and is then retracted by the winding device. A laser thinning machine is provided between the first and second cooling main drums.

[0014] This utility model also provides a method for preparing an ultrathin composite current collector, comprising the following steps:

[0015] Flatten the polymer film;

[0016] The polymer film is coated by depositing a first coating layer on one surface of the polymer film to form the current collection body.

[0017] The polymer film is thinned by thinning the polymer film side of the current collector, thereby reducing the thickness of the polymer film layer of the current collector.

[0018] The current collector is coated with a second coating on its surface.

[0019] Compared to existing technologies, this invention provides an ultra-thin composite current collector and its preparation equipment. The ultra-thin composite current collector includes a current collector body comprising a polymer film layer and a first coating layer. The first coating layer is disposed on the polymer film layer. The current collector body has a reduction zone on the side where the polymer film layer is located to reduce its thickness. A second coating layer is disposed on the current collector body, with the first coating layer located on the upper surface of the polymer film layer and the second coating layer located on the lower surface of the polymer film layer. This invention can significantly reduce the thickness of the polymer film layer, reduce the weight of the composite current collector, and increase the energy density of the battery. Furthermore, because the polymer film layer is relatively thick during the formation of the first coating layer, high-temperature particles composing the first coating layer will not burn through it during the formation process. During the formation of the second coating layer, due to the presence of the first coating layer and the polymer film layer, the high-temperature particles forming the second coating layer will not penetrate either the polymer film layer or the first coating layer, thus ensuring that the entire composite current collector will not be burned through. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the current collection body of the ultra-thin composite current collector provided by this utility model.

[0022] Figure 2 A schematic diagram of another state of the current collection body of the ultra-thin composite current collector provided by this utility model.

[0023] Figure 3 This is a schematic diagram of an embodiment of the ultra-thin composite current collector with tab structure provided by this utility model.

[0024] Figure 4 This is a schematic diagram of another embodiment of the ultra-thin composite current collector with tab structure provided by this utility model.

[0025] Figure 5 A schematic diagram of the winding mechanism of the ultra-thin composite current collector preparation equipment provided by this utility model.

[0026] Explanation of icon numbers:

[0027] 100 main collection points

[0028] Polymer film layer 10

[0029] First coating 11

[0030] Second coating 12

[0031] Cut Zone 13

[0032] 14 of the far ear

[0033] Adapter 15

[0034] substrate 16

[0035] Extended piece 17

[0036] Combined Zone 18

[0037] Unwinding device 210

[0038] First cooling main drum 220

[0039] Second Cooling Main Drum 230

[0040] Laser thinning machine 240

[0041] 250 winding device

[0042] Evaporation crucible 260 Detailed Implementation

[0043] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0044] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0045] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0046] like Figure 1 , Figure 2 As shown, this utility model provides an ultra-thin composite current collector and its preparation equipment. The ultra-thin composite current collector includes a current collector body 100, which comprises a polymer film layer 10 and a first coating layer 11. The first coating layer 11 is disposed on the polymer film layer 10. The current collector body 100 has a reduction region 13 on the side where the polymer film layer 10 is located to reduce its thickness. A second coating layer 12 is disposed on the current collector body 100. The first coating layer 11 is located on the upper surface of the polymer film layer 10, and the second coating layer 12 is located on the lower surface of the polymer film layer 10. This utility model can significantly reduce the thickness of the polymer film layer 10, reduce the weight of the composite current collector, and improve the energy density of the battery. Furthermore, because the polymer film layer is relatively thick when the first coating is formed, the high-temperature particles of the materials constituting the first coating will not burn through the polymer film layer during the formation process. During the formation of the second coating, the high-temperature particles forming the second coating will not penetrate the polymer film layer and the first coating due to the presence of the first coating and the polymer film layer, thus ensuring that the entire composite current collector will not be burned through.

[0047] This utility model also provides a method for preparing an ultrathin composite current collector, comprising the following steps:

[0048] S1. Flatten the polymer film;

[0049] S2. The polymer film is coated by coating a first coating 11 on one surface of the polymer film to form a current collection body 100.

[0050] S3. Thinning treatment is performed on the polymer film, and the polymer film side of the current collector 100 is thinned to reduce the thickness of the polymer film layer 10 of the current collector 100.

[0051] S4. The current collector 100 is coated with a second coating 12 on its surface.

[0052] Preferably, in the ultra-thin composite current collector provided by this invention, the thickness of the polymer film layer 10 is 6µm to 20µm. Preferably, in the ultra-thin composite current collector provided by this invention, the thickness of the first coating layer 11 is 500nm to 1500nm, and the thickness of the second coating layer 12 is 500nm to 1500nm. Preferably, in the ultra-thin composite current collector provided by this invention, with the polymer film layer 10 as the center, the second coating layer 12 is disposed on the opposite side of the first coating layer 11. In this invention, the first coating layer 11 and the second coating layer 12 are applied using vacuum deposition. The vacuum deposition equipment can be physicochemical deposition, such as vacuum evaporation, magnetron sputtering, etc.

[0053] Specifically, firstly, a polymer film with a thickness of 6µm-20µm is taken. Then, a first coating 11 is formed on one surface of the polymer film in the thickness direction using vacuum deposition. Next, the polymer film is thinned, with the thinning thickness ranging from 3µm to 16µm, to obtain a polymer film of a certain thickness. Finally, a second coating 12 is formed on the side of the polymer film opposite to the first coating 11 in the thickness direction using vacuum deposition. This method significantly reduces the thickness of the polymer film layer 10, lightens the weight of the composite current collector, and improves the energy density of the battery. Most importantly, this invention first forms the first coating 11 on a relatively thick polymer film layer 10, and then thins the polymer film layer 10 from the other side to form the first coating 11 and the second coating 12. Because of the presence of the first coating 11, the high-temperature particles of the second coating 12 will not burn through the film and the first coating 11 during the formation of the first coating 11. This method completely avoids the formation of pores in the film.

[0054] The polymer film can be made of any non-conductive material. The polymer film layer 10 of this invention can be a film formed from one or more of the following: polyamide, polyimide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyethylene, polypropylene, polypropylene, acrylonitrile-butadiene-styrene copolymer, polyvinyl alcohol, polystyrene, polyvinyl chloride, polyvinylidene fluoride, polytetrafluoroethylene, sodium polystyrene sulfonate, polyacetylene, silicone rubber, polyoxymethylene, polyphenylene ether, polyphenylene sulfide, polyethylene glycol, polysulfide polymers, polyphenylene, polypyrrole, polyaniline, polythiophene, polypyridine, cellulose, starch, protein, epoxy resin, and phenolic resin.

[0055] In this invention, the thinning equipment can be a laser thinning machine 240. The principle is that the polymer film vaporizes under the action of a laser to form a polymer film of a certain thickness. Simultaneously, this method allows the composite current collector of this invention to be formed in a vacuum coating equipment in one step. During coating in the vacuum coating equipment, the interior is under vacuum, and the vaporized polymer film can be removed by vacuum, eliminating the need to open the vacuum for further processing, reducing costs, improving efficiency, and preventing coating oxidation. A transition layer can also be formed between the first coating 11 and the second coating 12 and the polymer film layer 10. That is, a transition layer is provided between the first coating 11 and the polymer film layer 10, and a transition layer is also provided between the second coating 12 and the polymer film layer 10. This transition layer can improve the adhesion between the coating and the polymer film, making it less prone to peeling off. The first coating 11, the second coating 12, and the transition layer can all be made of materials such as alumina, silicon nitride, copper alloy, and aluminum alloy. In the preparation of the transition layer, a 6um-20um polymer film is first used, then a transition layer is formed on the polymer film, and then a first coating 11 and a second coating 12 are formed on the transition layer.

[0056] Preferably, the ultra-thin composite current collector provided by this utility model, such as Figure 3 As shown, the current collector body 100 further includes an electrode tab 14. The thickness of the polymer film layer 10 in the reduction region 13 where the electrode tab 14 is located is zero. The second coating 12 is disposed on the side of the polymer film layer 10 away from the first coating 11. Preferably, in the ultra-thin composite current collector provided by this invention, the length of the electrode tab 14 is 3µm-50µm. In the preparation process, a polymer film with a thickness of 6µm-20µm is first taken. Then, a first coating 11 is formed on one surface of the polymer film in the thickness direction using a vacuum deposition method. After the first coating 11 is formed, tab portions 14 are distinguished on the polymer film. A thinning device is used to thin the non-tab portion 14 area to a specified thickness, but a certain amount of polymer film is retained. At the same time, the thinning device completely removes the polymer film from the tab portion 14, leaving only the first coating 11 on the tab portion 14. Then, a second coating 12 is formed on the non-tab portion 14 area on the thinned side of the polymer film using a vacuum deposition device, thereby forming a composite current collector with a tab structure. The length of the tab portion 14 is 3µm-50µm.

[0057] Preferably, the ultra-thin composite current collector provided by this utility model further includes an adapter piece 15 in the current collector body 100. The base 16 of the adapter piece 15 is stacked and connected to the outer side of the second coating 12, and the protruding piece 17 of the adapter piece 15 is connected to the tab portion 14. First, a composite current collector with a tab structure is taken, and then the adapter piece 15 is stacked on the surface of the second coating 12. First, ultrasonic welding is used to weld the second coating 12 and the base 16 of the adapter piece 15, with the protruding piece 17 of the adapter piece 15 protruding from the end of the film. Then, the protruding piece 17 of the adapter piece 15 is welded to the tab portion 14, thereby completing the welding of the tab.

[0058] like Figure 4 As shown, preferably, in the ultra-thin composite current collector provided by this invention, the tab portion 14 has a bonding region 18 on the side where the cut-off region 13 is located, and the second coating 12 fills the bonding region 18. In this tab-structured composite current collector, the polymer film also has a bonding region 18, and the film in the bonding region 18 is completely removed by laser, allowing the first coating 11 and the second coating 12 to directly contact each other. Therefore, when the current collector of this invention is used in a battery, the current collected by the second coating 12 will pass through the first coating 11 and converge along the tab. With this arrangement, the conventional method of welding the adapter piece 15 to the tab can be eliminated, thereby reducing the mass of the current collector and increasing the energy density of the battery. It can also greatly reduce the cost of battery manufacturing. In this structure, the preparation method can be as follows: First, a polymer film with a thickness of 6um-20um is taken; then, a first coating 11 is formed on one surface of the polymer film in the thickness direction using a vacuum deposition method; after the first coating 11 is formed, an electrode tab 14 is separated on the polymer film, and a thinning device is used to thin the non-electrode tab 14 area to a specified thickness, but a certain amount of polymer film is retained. At the same time, the thinning device removes all the polymer film from the electrode tab 14, so that the electrode tab 14 only retains the first coating 11. A bonding area 18 is defined near the area where the polymer film is located on the electrode tab 14, and its length can be 3um-10um; then, a vacuum deposition device is used to perform vacuum deposition on the non-electrode tab 14 area and the bonding area 18 on the thinned side of the polymer film to form a second coating 12, thereby forming a composite current collector with an electrode tab structure that does not require an adapter plate 15.

[0059] like Figure 5As shown, this utility model also provides an ultra-thin composite current collector preparation device, including a vacuum chamber. An evaporation source and a winding mechanism for unfolding a polymer film are disposed within the vacuum chamber. The winding mechanism includes an unwinding device 210, a first cooling main drum 220, a second cooling main drum 230, and a winding device 250. The polymer film is unwound from the unwinding device 210, passes through the first and second cooling main drums 220, and is then retracted by the winding device 250. A laser thinning machine 240 is disposed between the first and second cooling main drums 220. Specifically, the evaporation source is an evaporation crucible 260. A guide roller is disposed between the unwinding device 210 and the first cooling main drum 220, two guide rollers are disposed between the first and second cooling main drums 230, and a guide roller is disposed between the winding device 250 and the second cooling main drum 230. After passing through the rollers, the polymer film passes through the first cooling drum 220. An evaporation crucible 260 is set below the first cooling drum 220. The evaporation crucible 260 mainly contains vapor deposition material to form a first coating 11 on one side of the polymer film. After passing through the first cooling drum 220, the film passes through another roller. A laser thinning machine 240 is set on the side of the polymer film where the first coating 11 has not been formed to thin the polymer film to a predetermined thickness. After passing through another roller, it reaches the second cooling drum 230. An evaporation crucible 260 is also set below the second cooling drum 230 to vapor deposit a second coating 12 on one side of the thinned polymer film. Then, the polymer film passes through the rollers and reaches the winding device 250 for winding.

[0060] In summary, this invention provides an ultra-thin composite current collector and its preparation equipment. The ultra-thin composite current collector includes a current collector body, which comprises a polymer film layer and a first coating layer. The first coating layer is disposed on the polymer film layer. The current collector body has a reduction zone on the side where the polymer film layer is located for reducing the thickness of the polymer film layer. A second coating layer is disposed on the current collector body. This invention can significantly reduce the thickness of the polymer film layer, reduce the weight of the composite current collector, and increase the energy density of the battery. Simultaneously, because the polymer film layer is relatively thick during the formation of the first coating layer, high-temperature particles composing the first coating layer will not burn through it. During the formation of the second coating layer, due to the presence of the first coating layer and the polymer film layer, high-temperature particles forming the second coating layer will not penetrate through the polymer film layer and the first coating layer, thus ensuring that the entire composite current collector will not be burned through. Because of the presence of the first and second coating layers and the sufficient thickness of the current collector, high-temperature particles passing through the second coating layer to the first coating layer will not burn through the film and the first coating layer, thereby completely avoiding the formation of film pores.

[0061] This invention provides a method for preparing an ultra-thin composite current collector. First, a polymer film with a thickness of 6µm-20µm is taken. Then, a first coating is formed on one surface of the polymer film along its thickness direction using vacuum deposition. Next, the polymer film is thinned to a thickness of 3µm-16µm to obtain a polymer film of a certain thickness. Finally, a second coating is formed on the side of the polymer film opposite to the first coating along its thickness direction using vacuum deposition. This method significantly reduces the thickness of the polymer film layer, lightens the weight of the composite current collector, and increases the energy density of the battery. Most importantly, this invention first forms a first coating on a relatively thick polymer film layer, then thins the polymer film layer from the other side to form the first coating and then forms the second coating. Because of the presence of the first coating, the high-temperature particles of the second coating will not burn through the film and the first coating during the formation of the first coating. This method completely avoids the formation of pores in the film.

[0062] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. An ultra-thin composite current collector, characterized in that, The device includes a current collector, which comprises a polymer film layer and a first coating layer. The first coating layer is disposed on the polymer film layer. The current collector has a reduction area on the side where the polymer film layer is located for reducing the thickness of the polymer film layer. The current collector has a second coating layer, with the first coating layer located on the upper surface of the polymer film layer and the second coating layer located on the lower surface of the polymer film layer.

2. The ultra-thin composite current collector according to claim 1, characterized in that, The thickness of the polymer film layer is 6µm to 20µm.

3. The ultra-thin composite current collector according to claim 2, characterized in that, The thickness of the first coating is 500nm to 1500nm, and the thickness of the second coating is 500nm to 1500nm.

4. The ultra-thin composite current collector according to claim 1, characterized in that, The second coating is disposed on the opposite side of the first coating, and a transition layer is further disposed between the first coating and the polymer film layer.

5. The ultra-thin composite current collector according to claim 4, characterized in that, A transition layer is also provided between the second coating and the polymer film layer.

6. The ultra-thin composite current collector according to claim 1, characterized in that, The current collector also includes an electrode tab, and the thickness of the polymer film layer in the cut-off region where the electrode tab is located is zero. The second coating is disposed on the side of the polymer film layer away from the first coating.

7. The ultra-thin composite current collector according to claim 6, characterized in that, The length of the tab is 3um-50um.

8. The ultra-thin composite current collector according to claim 6, characterized in that, The current collector body also includes an adapter plate, the base of which is overlapped and connected to the outer side of the second coating, and the protruding part of the adapter plate is connected to the tab.

9. The ultra-thin composite current collector according to claim 6, characterized in that, The tab portion has a bonding area on the side where the cut area is located, and the second coating fills the bonding area.

10. A device for preparing an ultra-thin composite current collector, characterized in that, The device includes a vacuum chamber, which contains an evaporation source and a winding mechanism for unfolding a polymer film. The winding mechanism includes an unwinding device, a first cooling main drum, a second cooling main drum, and a winding device. The polymer film is unwound from the unwinding device, passes through the first and second cooling main drums, and is then retracted by the winding device. A laser thinning machine is disposed between the first and second cooling main drums.

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