High-performance composite current collector, pole piece, battery and preparation method

Abstract

The invention relates to the technical field of lithium ion batteries, in particular to a high-performance composite current collector, a pole piece, a battery and a preparation method. The high-performance composite current collector comprises a polymer layer, a first metal layer arranged on one surface of the polymer layer and a second metal layer arranged on the other surface of the polymer layer; the polymer layer at least comprises a pole piece area and a tab area; a pore channel is formed in the tab area of the polymer layer and is filled with a conductive material; micropores are formed in the pole piece area of the polymer layer, and the micropores are filled with a metal material which is the same as that of the second metal layer. The invention also provides a preparation method of the high-performance composite current collector, a pole piece and a battery. The problem that the existing composite current collector cannot be directly welded with an external tab is solved, the conductivity, the strength and the safety are improved, and the problems of insufficient welding and poor contact of a welding position during tab welding of the existing composite current collector are solved. And the problems of insufficient welding strength and easy generation of wrinkles, cracks or fractures of the tabs of the existing composite current collector are solved.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, specifically to a high-performance composite current collector, electrode, battery, and preparation method. Background Technology

[0002] With the booming development of new energy vehicles and energy storage, lithium-ion batteries are increasingly becoming the mainstream choice for energy storage due to their superior performance. Current collectors, as a crucial raw material for lithium-ion batteries, not only bear the important responsibility of collecting current and reducing battery internal resistance, but also play a key role in improving battery energy density and enhancing rate performance.

[0003] Traditional current collectors typically use metal foil, which has a relatively simple manufacturing process and convenient tab welding. Simply attaching the tab close to the pre-drilled welding position on the current collector easily achieves through-conductivity between layers. This process has been widely used in long-term battery production practice and is technologically mature. However, as battery performance requirements continue to increase, the limitations of traditional current collectors are becoming increasingly apparent. Their relatively heavy weight limits further improvements in battery energy density and makes it difficult to meet increasingly stringent safety requirements.

[0004] To overcome this bottleneck, composite current collectors have emerged. They utilize polymers such as PET (polyethylene terephthalate), PP (polypropylene), and PI (polyimide) as carriers, cleverly constructing a "metal layer-polymer material-metal layer" sandwich structure through a one-step or two-step process. This unique structural design endows composite current collectors with numerous advantages. They are lighter, effectively reducing the overall weight of the battery and thus significantly improving its energy density. Simultaneously, the polymer material in the middle layer possesses excellent insulation and thermal stability, effectively blocking current and preventing thermal runaway when the battery is subjected to external impact or internal short circuit. This greatly enhances battery safety and provides strong support for the application of lithium-ion batteries in fields with extremely high safety requirements, such as new energy vehicles.

[0005] However, the welding of the tabs in composite current collectors has become a key challenge restricting their large-scale application. Unlike traditional current collectors, the middle polymer layer of composite current collectors is an insulating material, which presents numerous challenges to the tab welding process. During welding, the high ductility of the polymer material allows it to absorb a large amount of ultrasonic energy, preventing energy from being effectively transferred to the metal layer during ultrasonic welding. This hinders proper fusion between the metal layers, thus preventing conductive conduction. To address this issue, transition welding or pressure welding are commonly used for tab welding. However, these welding methods are extremely difficult, requiring very high precision in equipment and strict control of welding parameters. Even slight errors can lead to welding failure. This not only results in low processing yield and increased production costs but also causes problems such as incomplete welds and poor contact at the weld points. These problems are particularly prominent during battery charging and discharging. Incomplete welds and poor contact at the weld points generate additional resistance, leading to localized heating, which in turn causes a decline in battery performance and may even pose safety hazards such as battery bulging and fire, seriously affecting battery life and reliability.

[0006] Currently, the tabs of composite current collectors are mainly fabricated through foil folding and roll welding. However, this process also has several problems. First, poor welding: due to the barrier of the polymer layer, the metal layer in the tab area cannot be directly fused, resulting in insufficient welding strength, which is difficult to meet the requirements of battery use under complex operating conditions. Second, rolling deformation: the elongation rate of the pure metal tab and the composite area differs greatly. During the rolling process, the tab is prone to wrinkles or even breakage, which not only affects the appearance quality of the battery but may also lead to damage to the internal structure of the battery, reducing battery performance and consistency. In addition, stress concentration: the traditional straight boundary design is prone to fatigue cracks during machining. These cracks will continue to propagate during battery use, eventually leading to battery structural damage and safety accidents.

[0007] In conclusion, how to effectively improve the welding process of composite current collector tabs, enhance welding quality, and reduce process difficulty and cost is an urgent problem to be solved in the current development of the lithium-ion battery industry. Summary of the Invention

[0008] In view of this, one objective of the present invention is to provide a high-performance composite current collector to solve the problem that existing composite current collectors cannot be directly welded to external tabs, while improving conductivity, strength and safety. Another objective of the present invention is to provide a method for preparing a high-performance composite current collector, an electrode sheet and a battery to solve the problems of incomplete welding and poor contact at the welding position in the tab welding of existing composite current collectors, as well as the problems of insufficient welding strength and easy wrinkling, cracking or breakage of the tab welding of existing composite current collectors.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-performance composite current collector includes a polymer layer, a first metal layer disposed on one side of the polymer layer, and a second metal layer disposed on the other side of the polymer layer; The polymer layer has at least a polar plate region and a tab region; A channel is formed in the tab region of the polymer layer, and the channel is filled with a conductive material, so that the first metal layer and the second metal layer are connected through the conductive material. Micropores are formed in the electrode region of the polymer layer, and the micropores are filled with the same metal material as the second metal layer, so that the first metal layer and the second metal layer are connected through the metal material in the micropores.

[0010] By dividing the polymer layer into a tab region and an electrode region, and setting channels in the tab region and filling the channels with conductive material, the conductive material can be directly used as a tab to weld external tabs. This effectively solves the problem that existing composite current collectors cannot be directly welded to external tabs. It also increases the conductivity of the tab and the welding area, avoiding the problem of poor welding caused by poor contact during traditional tab welding. Simultaneously, by processing micropores in the electrode area and depositing the same metal material as the second metal layer within the micropores, electron conduction on both sides of the composite current collector is effectively achieved under normal operating conditions. This reduces the battery's DC internal resistance, thereby reducing localized heat generation and improving conductivity and safety. The metal material in the microporous structure allows the metal layers on both sides of the polymer layer to connect together in an I-shaped structure, thus interlocking the polymer layer and the two metal layers into a whole. The interconnection of the two metal layers effectively improves the adhesion between the metal layer and the polymer layer, reduces the difference in expansion and contraction between them, and thus improves the overall strength. This not only solves the problem of poor adhesion between the metal layer and the polymer layer in existing composite current collectors, but also solves the problem of the polymer material in the middle of existing composite current collectors causing the metal layer and polymer to separate due to the difference in expansion and contraction between the polymer material and the upper and lower metal layers during battery operation. Batteries made with the composite current collector of this invention can significantly improve battery life and safety performance.

[0011] Preferably, the polymer layer has an electrode region, a tab region, and a transition region located between the electrode region and the tab region; the transition region has gradient micropores filled with conductive material to improve the conductivity of the transition region and reduce heat generation, thereby further improving the battery's lifespan and safety performance.

[0012] Preferably, the gradient micropores are gradient micropores whose diameter gradually increases from the electrode region to the tab region.

[0013] Preferably, the channel of the tab region extends to the transition region, so that the conductive material in the channel is directly connected to the first metal layer and the second metal layer of the electrode region, thereby shortening the ion passage path and improving conductivity.

[0014] Preferably, the channels in the tab region are rectangular structures formed at intervals throughout the tab region, triangular structures formed at intervals, or pores formed at intervals.

[0015] Preferably, a first seed layer is provided between the polymer layer and the first metal layer.

[0016] Preferably, a second seed layer is provided between the polymer layer and the second metal layer.

[0017] Preferably, the thickness of the polymer layer is 2~10 μm.

[0018] Preferably, the thickness of the polymer layer is 2um, 2.5um, 3um, 3.5um, 4um, 4.5um, 6um, 7um, 8um, or 10um.

[0019] Preferably, the thickness of the first metal layer is 0.5~3 μm.

[0020] Preferably, the thickness of the first metal layer is 0.5um, 0.8um, 1um, 2um, 2.5um or 3um.

[0021] Preferably, the thickness of the second metal layer is 0.5~3 μm.

[0022] Preferably, the thickness of the second metal layer is 0.5um, 0.8um, 1um, 2um, 2.5um or 3um.

[0023] Preferably, the thickness of the high-performance composite current collector is 3~16µm.

[0024] Preferably, the material of the polymer layer is selected from at least one of PET (polyethylene terephthalate), BOPP (polypropylene), PE (polyethylene), and PI (polyimide).

[0025] This invention also provides a method for preparing a high-performance composite current collector, comprising the following steps: S1. Deposit a first metal layer on one side of the polymer layer; S2. Process pores from the other side of the polymer layer, and then deposit conductive material in the pores to serve as tabs; S3. Deposit a second metal layer on the other side of the polymer layer to obtain a high-performance composite current collector.

[0026] By depositing metal layers on both sides of the polymer layer and depositing conductive material in the channels to serve as tabs, the problem of direct welding of external tabs in existing composite current collectors is effectively solved. First, a first metal layer is deposited on one side of the polymer layer, providing a good conductive foundation for the current collector. Then, channels are machined on the other side and conductive material is deposited to serve as tabs. This design not only increases the conductivity and welding area of ​​the tabs but also avoids the problem of poor soldering caused by poor contact during traditional tab welding. By depositing a second metal layer on the other side of the polymer layer, the overall strength and conductivity of the current collector are further enhanced, effectively preventing wrinkles, cracks, or fractures during welding, improving welding strength and reliability, and thus significantly improving the performance and service life of the composite current collector.

[0027] Preferably, step S1 includes: depositing a first seed layer on one side of the polymer layer, and then depositing a first metal layer on the first seed layer.

[0028] Preferably, step S3 includes: depositing a second seed layer on the other side of the polymer layer, and then depositing a second metal layer on the second seed layer to obtain a high-performance composite current collector.

[0029] Preferably, step S1 includes: depositing a first seed layer on one side of the polymer layer using a vacuum magnetron sputtering process, and then depositing a first metal layer on the first seed layer using an electroplating process.

[0030] Preferably, step S2 includes: dividing the polymer layer into an electrode region and an electrode tab region; processing a channel in the electrode tab region from the other side of the polymer layer using a laser cutting or punching process; and then depositing a conductive material in the channel using an electroplating process to serve as an electrode tab, so that the first metal layer and the second metal layer are connected through the conductive material.

[0031] Preferably, the channels in the tab region are rectangular structures formed at intervals throughout the tab region, triangular structures formed at intervals, or pores formed at intervals.

[0032] The pores can be circular, triangular, rectangular, or polygonal, etc.

[0033] Preferably, the diameter of the channel in the electrode area is greater than 30% of the entire electrode area.

[0034] Preferably, step S3 includes: depositing a second seed layer on the other side of the polymer layer using a vacuum magnetron sputtering process, and then depositing a second metal layer on the second seed layer using an electroplating process to obtain a high-performance composite current collector.

[0035] Preferably, in step S1, the process parameters for depositing the first seed layer on one side of the polymer layer using vacuum magnetron sputtering are: argon flow rate of 80~250 sccm, single target power of 4~25 kW, unwinding tension of 80~150 N, winding tension of 80~150 N, and coating vacuum degree ≤ 8.0*10 -4 The production speed is 20~30m / min.

[0036] Preferably, in step S1, the process parameters for depositing the first metal layer on the first seed layer using electroplating are: total current of 1400A~3000A, anti-oxidation current of 1.5~3A, unwinding tension of 40~120N, winding tension of 20~110N, and production speed of 5~15m / min.

[0037] Preferably, in step S2, the process parameters for depositing conductive material in the channel using an electroplating process to form the tab are: total current of 3500A~5000A, unwinding tension of 40~120N, winding tension of 20~110N, and production speed of 1±5m / min.

[0038] Preferably, in step S3, the process parameters for depositing the second seed layer on the other side of the polymer layer using vacuum magnetron sputtering are as follows: argon flow rate 80~250 sccm, single target power 4~25 kW, unwinding tension 80~150 N, winding tension 80~150 N, and coating vacuum degree ≤8.0*10 -4 The production speed is 20~30m / min.

[0039] Preferably, in step S3, the process parameters for depositing the second metal layer on the second seed layer using electroplating are: total current of 1400A~3000A, anti-oxidation current of 1.5~3A, unwinding tension of 40~120N, winding tension of 20~110N, and production speed of 5~15m / min.

[0040] Preferably, step S2 further includes: processing micropores in the electrode area from the other side of the polymer layer using laser cutting or punching processes; S3 further includes: while depositing a second metal layer on the other side of the polymer layer, depositing the same metal material as the second metal layer in the micropores processed in the electrode region to obtain a high-performance composite current collector.

[0041] By fabricating micropores in the electrode region and depositing the same metal material as the second metal layer within these micropores simultaneously with the deposition of the second metal layer, electron conduction on both sides of the composite current collector is effectively achieved under normal operating conditions. This reduces the battery's DC internal resistance. Furthermore, the metal material within the microporous structure allows the metal layers on both sides of the polymer layer to connect together in an I-shaped structure, thus interconnecting the two metal layers and effectively improving the adhesion between the metal and polymer layers. This not only solves the problem of poor adhesion between the metal and polymer layers in existing composite current collectors but also addresses the issue of the polymer material in the middle of existing composite current collectors, which, due to differences in expansion and contraction between the polymer material and the two metal layers, causes separation of the metal and polymer layers during battery operation. This solution, by creating micropores and placing metal material within them, interlocks the polymer layer and the two metal layers, reducing their expansion and contraction differences. Batteries made with this composite current collector can significantly improve battery life.

[0042] Preferably, the micropores are selected from circular pores with a diameter of 50 μm, and the spacing between adjacent micropores is 1 mm.

[0043] Preferably, step S2 includes: dividing the polymer layer into an electrode region, an electrode tab region, and a transition region located between the electrode region and the electrode tab region; A channel is processed in the tab area from the other side of the polymer layer using laser cutting or punching process, and then a conductive material is deposited in the channel using electroplating process to serve as a tab, so that the first metal layer and the second metal layer are connected through the conductive material. Micropores are processed in the electrode area from the other side of the polymer layer using laser cutting or punching processes. The pore size of the micropores is 5~1000um and the spacing between adjacent micropores is 1mm. From the other side of the polymer layer, a gradient micropore with gradually increasing pore size from the electrode area to the tab area is processed in the transition region using laser cutting or punching. Then, a conductive material is deposited in the gradient micropore using an electroplating process to improve the conductivity of the transition region and reduce heat generation. S3 further includes: while depositing a second metal layer on the other side of the polymer layer, depositing the same metal material as the second metal layer in the micropores processed in the electrode region to obtain a high-performance composite current collector.

[0044] Preferably, step S2 includes: dividing the polymer layer into an electrode region, an electrode tab region, and a transition region located between the electrode region and the electrode tab region; A channel is processed in the tab region from the other side of the polymer layer using laser cutting or punching technology and extends to the transition region. Then, a conductive material is deposited in the channel using an electroplating process to serve as a tab, so that the first metal layer and the second metal layer are connected through the conductive material. At the same time, the conductive material deposited in the channel extending to the transition region is directly connected to the first metal layer and the second metal layer of the electrode region to improve conductivity. Micropores are processed in the electrode area from the other side of the polymer layer using laser cutting or punching processes. The pore size of the micropores is 5~1000um and the spacing between adjacent micropores is 1mm. From the other side of the polymer layer, a gradient micropore with gradually increasing pore size from the electrode area to the tab area is processed in the transition region using laser cutting or punching. Then, a conductive material is deposited in the gradient micropore using an electroplating process to improve the conductivity of the transition region and reduce heat generation. S3 further includes: while depositing a second metal layer on the other side of the polymer layer, depositing the same metal material as the second metal layer in the micropores processed in the electrode region to obtain a high-performance composite current collector.

[0045] Preferably, the pore size of the gradient micropores gradually increases from the electrode region to the tab region, and is 80um, 110um, 140um and 170um respectively.

[0046] Preferably, the micropores in the electrode region are selected from circular pores with diameters of 5um, 30um, 50um, 60um, 80um, 100um, or 300um.

[0047] Preferably, the micropores in the electrode region account for 2-20% of the total electrode region.

[0048] By controlling the proportion of micropores in the electrode area, we can effectively improve the tensile strength, extend the service life, and balance production costs.

[0049] Preferably, step S1 includes: depositing a first metal layer on one side of the polymer layer using an evaporation deposition process.

[0050] Preferably, step S3 includes: depositing a second metal layer on the other side of the polymer layer using an evaporation deposition process to obtain a high-performance composite current collector.

[0051] Preferably, in S1 and S3, the process parameters for the evaporation coating process are: wire feed speed of 100~300 mm / min, evaporation boat current of 500~1500 A, unwinding tension of 150~280 N, winding tension of 120~250 N, and coating vacuum degree of 0.8*10 - 2pa~5.0*10 -4 The production speed is 22~28m / min.

[0052] Preferably, the material of the polymer layer is selected from at least one of PET (polyethylene terephthalate), BOPP (polypropylene), PE (polyethylene), and PI (polyimide).

[0053] Preferably, the polymer layer is made of at least one of PET, BOPP and PI.

[0054] Among them, because the core of the composite current collector is a polymer material, its density is lower than that of pure metals; for example, the density of copper is 8.92-8.96 g / cm³. 3 The density of aluminum is 2.7 g / cm³. 3 The density of polymer materials such as PET is 1.33~1.38 g / cm³. 3 The density of PP is generally 0.89~0.91 g / cm³. 3 Therefore, by replacing high-density metal with low-density polymer in the composite current collector, the weight and thickness of the composite current collector are effectively reduced. The high-performance composite current collector of this invention reduces the amount of metal by about 50% to 80%, thereby significantly reducing the overall weight of the battery.

[0055] Preferably, when the first metal layer, the second metal layer, the first seed layer, and the second seed layer are made of aluminum, the resulting high-performance composite current collector is a positive electrode current collector.

[0056] Preferably, when the first metal layer, the second metal layer, the first seed layer, and the second seed layer are made of copper, the resulting high-performance composite current collector is a negative electrode current collector.

[0057] The high-performance composite current collector of the present invention provides a metal layer in a local area of ​​the composite current collector to directly connect the metal layers on the upper and lower surfaces of the polymer layer, so that the upper and lower metal layers of the composite current collector are directly conductive, and the external electrode tab can be directly welded after the battery electrode is prepared.

[0058] Furthermore, this invention proposes a dual mechanism to improve the welding reliability of the tab by combining a metallized structure and a composite structure in the tab area. The welding position is entirely composed of metal to ensure welding strength and conductivity, while the non-welding area is a composite structure to improve the strength and flexibility of the tab and to act as a buffer layer to absorb plastic strain. The material elongation gradient matches the roll pressure distribution to improve the resistance to roll pressure in the tab area. The elongation of the composite material is 5~10%, and the elongation of the metal area is 1~5%. Mass production can be achieved through laser etching + electroplating processes.

[0059] Preferably, the thickness of the high-performance composite current collector is 3~16µm.

[0060] The present invention also provides an electrode, wherein the current collector of the electrode is a high-performance composite current collector prepared by the preparation method described in the present invention.

[0061] The present invention also provides a battery, wherein the electrode of the battery is the electrode described in the present invention.

[0062] Preferably, the battery is a lithium-ion battery.

[0063] The beneficial effects of this invention are: This invention relates to a high-performance composite current collector. By dividing the polymer layer into a tab region and an electrode region, and creating channels in the tab region and filling these channels with conductive material, the conductive material can be directly used as the tab for welding external tabs. This effectively solves the problem of existing composite current collectors being unable to directly weld external tabs, and also increases the conductivity of the tab and the welding area, avoiding the problem of poor soldering caused by poor contact during traditional tab welding. Simultaneously, by processing micropores in the electrode region and depositing the same metal material as the second metal layer within these micropores, electron conduction on both sides of the composite current collector is effectively achieved under normal operating conditions. This reduces the battery's DC internal resistance, thereby reducing localized heat generation and improving conductivity and safety. The metal material in the microporous structure allows the metal layers on both sides of the polymer layer to be connected together in an I-shaped structure, thus interlocking the polymer layer and the two metal layers into a whole. This interconnection of the two metal layers effectively improves the adhesion between the metal layers and the polymer layer, reduces the difference in expansion and contraction between them, and thus enhances the overall strength.

[0064] The present invention discloses a method for preparing a high-performance composite current collector. By depositing metal layers on both sides of a polymer layer and depositing conductive material in the channels to serve as tabs, it effectively solves the problem that existing composite current collectors cannot be directly welded to external tabs. First, a first metal layer is deposited on one side of the polymer layer, providing a good conductive foundation for the current collector. Then, channels are processed on the other side and conductive material is deposited to serve as tabs. This design not only increases the conductivity and welding area of ​​the tabs but also avoids the problem of poor soldering caused by poor contact during traditional tab welding. By depositing a second metal layer on the other side of the polymer layer, the overall strength and conductivity of the current collector are further enhanced, effectively preventing wrinkles, cracks, or fractures during welding, improving welding strength and reliability, and thus significantly improving the performance and service life of the composite current collector. This method has significant application value in the field of lithium-ion battery technology. Attached Figure Description

[0065] Figure 1 This is a schematic cross-sectional view of the tab region of the high-performance composite current collector for negative electrodes prepared in Example 1; Figure 2This is a plan view of the polymer layer of the high-performance composite current collector for negative electrodes prepared in Example 3; Figure 3 This is a plan view of the polymer layer of the high-performance composite current collector for negative electrodes prepared in Example 7; Wherein, 1-polymer layer, 2-tab, 3-first seed layer, 4-first metal layer, 5-second seed layer, 6-second metal layer, 01-electrode region, 02-transition region, 03-tab region. Detailed Implementation

[0066] The following description, with reference to preferred embodiments, illustrates the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are merely illustrative of the present invention and not intended to limit the scope of protection of the present invention.

[0067] Where specific techniques or conditions are not specified in the detailed embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0068] Example 1 A method for preparing a high-performance composite current collector with a negative electrode includes the following steps: S1, such as Figure 1 As shown, a PP film with a thickness of 4.5 μm is used as the polymer layer 1. A copper layer is deposited on one side of the polymer layer 1 as the first seed layer 3 using a vacuum magnetron sputtering process. The thickness of the first seed layer 3 is 50 nm. Then, a copper layer is deposited on the first seed layer 3 as the first metal layer 4 using an electroplating process. The thickness of the first metal layer 4 is 1000 nm. The process parameters for depositing the first seed layer 3 on one side of the polymer layer 1 using vacuum magnetron sputtering are as follows: argon gas flow rate is 120 sccm, single target power is 15 kW, unwinding tension is 100 N, winding tension is 80 N, and coating vacuum degree is 6.0*10 -4 pa, with a production speed of 20m / min; The process parameters for depositing the first metal layer 4 on the first seed layer 3 using electroplating are as follows: total current is 2500A, anti-oxidation current is 3A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min. S2. Divide the polymer layer 1 into an electrode area and an electrode tab area. From the other side of the polymer layer 1, use laser cutting to process rectangular channels with a width of 6mm and a length of 8mm at intervals in the electrode tab area. Then, use an electroplating process to deposit metallic copper in the rectangular channels as electrode tab 2, so that the first metal layer and the second metal layer are connected through metallic copper. Among them, the process parameters for electrode 2 are as follows: the total current is 4000A, the unwinding tension is 120N, the winding tension is 110N, and the production speed is 5m / min; the thickness of the electrode is equal to the thickness of the polymer layer, that is, the thickness of the electrode is 4.5um. S3. Copper is deposited on the other side of the polymer layer 1 as a second seed layer 5 using a vacuum magnetron sputtering process. The thickness of the second seed layer 5 is 50 nm. Then, copper is deposited on the second seed layer 5 as a second metal layer 6 using an electroplating process. The thickness of the second metal layer 6 is 1000 nm, thus obtaining a high-performance composite current collector for the negative electrode. The process parameters for depositing the second seed layer 5 on the other side of the polymer layer 1 using vacuum magnetron sputtering are as follows: argon flow rate 120 sccm, single target power 15 kW, unwinding tension 100 N, winding tension 80 N, and coating vacuum degree 6.0*10 -4 pa, with a production speed of 20m / min; The process parameters for depositing the second metal layer 6 on the second seed layer 5 using electroplating are as follows: total current is 2500A, anti-oxidation current is 3A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min. The cross-sectional diagram of the tab region of the obtained high-performance composite current collector is shown below. Figure 1 As shown.

[0069] Example 2 A method for preparing a high-performance composite current collector with a negative electrode includes the following steps: S1. Using a PP film material with a thickness of 4.5um as the polymer layer, a copper layer is deposited on one side of the polymer layer as the first seed layer using a vacuum magnetron sputtering process. The thickness of the first seed layer is 50nm. Then, a copper layer is deposited on the first seed layer as the first metal layer using an electroplating process. The thickness of the first metal layer is 1000nm. The process parameters for depositing the first seed layer on one side of the polymer layer using vacuum magnetron sputtering are as follows: argon flow rate 120 sccm, single target power 15 kW, unwinding tension 100 N, winding tension 80 N, and coating vacuum degree 6.0*10 - 4 pa, with a production speed of 20m / min; The process parameters for depositing the first metal layer on the first seed layer using electroplating are as follows: total current is 2500A, anti-oxidation current is 3A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min. S2. Divide the polymer layer into an electrode area and an electrode tab area. From the other side of the polymer layer, use a punching process to process rectangular channels with a width of 6 mm and a length of 8 mm at intervals in the electrode tab area. At the same time, from the other side of the polymer layer, use a punching process to process micropores at intervals in the electrode area. The micropores are circular holes with a diameter of 50 μm and a spacing of 1 mm. Then, use an electroplating process to deposit metallic copper in the rectangular channels to serve as electrodes, so that the first metal layer and the second metal layer are connected through metallic copper. Among them, the process parameters for depositing metallic copper in the rectangular channels of the electrode area using electroplating are as follows: total current is 4000A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min; the thickness of the electrode is equal to the thickness of the polymer layer. S3. Copper is deposited on the other side of the polymer layer as a second seed layer using vacuum magnetron sputtering. At the same time, copper is also deposited in the micropores of the electrode area using vacuum magnetron sputtering with the same parameters as the second seed layer. The thickness of the second seed layer is 50 nm. Then, copper is deposited on the second seed layer as a second metal layer using electroplating. The thickness of the second metal layer is 1000 nm, resulting in a high-performance composite current collector for the negative electrode. The process parameters for depositing a second seed layer on the other side of the polymer layer and depositing copper in the micropores of the electrode region using vacuum magnetron sputtering are as follows: argon flow rate 120 sccm, single target power 15 kW, unwinding tension 100 N, winding tension 80 N, and coating vacuum degree 6.0*10 -4 pa, with a production speed of 20m / min; The process parameters for depositing the second metal layer on the second seed layer using electroplating are as follows: total current is 2500A, anti-oxidation current is 3A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min.

[0070] Example 3 A method for preparing a high-performance composite current collector with a negative electrode includes the following steps: S1. Using a PP film material with a thickness of 4.5um as the polymer layer, a copper layer is deposited on one side of the polymer layer as the first seed layer using a vacuum magnetron sputtering process. The thickness of the first seed layer is 50nm. Then, a copper layer is deposited on the first seed layer as the first metal layer using an electroplating process. The thickness of the first metal layer is 1000nm. The process parameters for depositing the first seed layer on one side of the polymer layer using vacuum magnetron sputtering are as follows: argon flow rate 120 sccm, single target power 15 kW, unwinding tension 100 N, winding tension 80 N, and coating vacuum degree 6.0*10 - 4 pa, with a production speed of 20m / min; The process parameters for depositing the first metal layer on the first seed layer using electroplating are as follows: total current is 2500A, anti-oxidation current is 3A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min. S2, such as Figure 2 As shown, the polymer layer is divided into an electrode region 01, an electrode tab region 03, and a transition region 02 located between the electrode region 01 and the electrode tab region 03. From the other side of the polymer layer, laser cutting is used to process circular pores with a diameter of 200 μm at intervals in the electrode tab region 03, with a spacing of 1 mm between adjacent pores. Simultaneously, from the other side of the polymer layer, laser cutting is used to process micropores at intervals in the electrode region 01. These micropores are circular pores with a diameter of 50 μm and a spacing of 1 mm. Furthermore, laser cutting is used from the other side of the polymer layer... Light cutting is used to process gradient circular holes at intervals in the transition region 02. The gradient circular holes gradually increase in size from the electrode region 01 to the tab region 03, with values ​​of 80um, 110um, 140um, and 170um respectively. The spacing between adjacent gradient circular holes is 200um. Then, a water electroplating process is used to deposit metallic copper in the pores of the circular holes to serve as tabs, so that the first metal layer and the second metal layer are connected through metallic copper. At the same time, a water electroplating process with the same pore parameters as the circular holes is used to deposit metallic copper in the gradient circular holes in the transition region. The process parameters for depositing metallic copper in the circular holes of the tab area and the gradient circular holes of the transition area using electroplating are as follows: total current is 3500A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min; the thickness of the tab is equal to the thickness of the polymer layer. Figure 2 In the diagram, the area with blue circular holes represents electrode area 01, the area with orange dots represents transition area 02, and the area with red dots represents tab area 03. S3. Copper is deposited on the other side of the polymer layer as a second seed layer using a vacuum magnetron sputtering process. The thickness of the second seed layer is 50 nm. At the same time, copper is also deposited in the micropores of the electrode area using a vacuum magnetron sputtering process with the same parameters as the second seed layer. Then, copper is deposited on the second seed layer as a second metal layer using an electroplating process. The thickness of the second metal layer is 1000 nm, resulting in a high-performance composite current collector for the negative electrode. The process parameters for depositing a second seed layer on the other side of the polymer layer and depositing copper in the micropores of the electrode region using vacuum magnetron sputtering are as follows: argon flow rate 80 sccm, single target power 25 kW, unwinding tension 150 N, winding tension 150 N, and coating vacuum degree 8.0*10 -4 pa, with a production speed of 20m / min; The process parameters for depositing the second metal layer on the second seed layer using electroplating are as follows: total current is 2000A, anti-oxidation current is 3A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min.

[0071] Example 4 A method for preparing a high-performance composite current collector with a positive electrode includes the following steps: S1. Using a 6µm thick PET film as the polymer layer, an aluminum layer is deposited on one side of the polymer layer as the first metal layer using an evaporation coating process. The thickness of the first metal layer is 1000nm. The process parameters for depositing the first metal layer on one side of the polymer layer in the evaporation coating process are as follows: wire feed speed 300 mm / min, evaporation boat current 1000 A, unwinding tension 150 N, winding tension 120 N, and coating vacuum degree 0.8*10 - 3 pa, with a production speed of 22m / min; S2. Divide the polymer layer into an electrode area and an electrode tab area. From the other side of the polymer layer, use laser cutting to process rectangular channels with a width of 6mm and a length of 8mm at intervals in the electrode tab area. Then, use an electroplating process to deposit metallic aluminum in the rectangular channels as electrodes, so that the first metal layer and the second metal layer are connected through metallic aluminum. Among them, the process parameters for depositing metallic aluminum in the rectangular channels of the electrode area using electroplating are as follows: total current is 3500A, unwinding tension is 120N, winding tension is 10N, and production speed is 5m / min; the thickness of the electrode is equal to the thickness of the polymer layer. S3. An aluminum layer is deposited on the other side of the polymer layer as a second metal layer using an evaporation coating process. The thickness of the second metal layer is 1000 nm, resulting in a high-performance composite current collector for the positive electrode. The process parameters for depositing a second metal layer on the other side of the polymer layer in the evaporation coating process are as follows: wire feed speed 300 mm / min, evaporation boat current 1000 A, unwinding tension 150 N, winding tension 120 N, and coating vacuum degree 0.8*10 -3 The production speed is 22 m / min.

[0072] Example 5 A method for preparing a high-performance composite current collector with a positive electrode includes the following steps: S1. Using a 6µm thick PET film as the polymer layer, an aluminum layer is deposited on one side of the polymer layer as the first metal layer using an evaporation coating process. The thickness of the first metal layer is 1000nm. The process parameters for depositing the first metal layer on one side of the polymer layer in the evaporation coating process are as follows: wire feed speed 300 mm / min, evaporation boat current 1000 A, unwinding tension 150 N, winding tension 120 N, and coating vacuum degree 2*10 - 3 pa, with a production speed of 20m / min; S2. Divide the polymer layer into an electrode area and an electrode tab area. From the other side of the polymer layer, use a punching process to process rectangular channels with a width of 6 mm and a length of 8 mm at intervals in the electrode tab area. At the same time, from the other side of the polymer layer, use a punching process to process micropores at intervals in the electrode area. The micropores are circular holes with a diameter of 80 μm and a spacing of 1 mm. Then, use an electroplating process to deposit metallic aluminum in the rectangular channels to serve as electrodes, so that the first metal layer and the second metal layer are connected through metallic aluminum. Among them, the process parameters for depositing metallic aluminum in the rectangular channels of the electrode area using electroplating are as follows: total current is 3500A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min; the thickness of the electrode is equal to the thickness of the polymer layer. S3. An aluminum layer is deposited on the other side of the polymer layer as a second metal layer using an evaporation coating process. The thickness of the second metal layer is 1000 nm. At the same time, aluminum is also deposited in the micropores of the electrode area using an evaporation coating process with the same parameters as the second metal layer, so as to obtain a high-performance composite current collector for the positive electrode. The process parameters for the evaporation coating process, which involves depositing a second metal layer on the other side of the polymer layer and depositing aluminum in the micropores of the electrode area, are as follows: wire feed speed 300 mm / min, evaporation boat current 1000 A, unwinding tension 150 N, winding tension 120 N, and coating vacuum degree 2*10 -3 pa, with a production speed of 20m / min.

[0073] Example 6 A method for preparing a high-performance composite current collector with a positive electrode includes the following steps: S1. Using a 6µm thick PET film as the polymer layer, an aluminum layer is deposited on one side of the polymer layer as the first metal layer using an evaporation coating process. The thickness of the first metal layer is 1000nm. The process parameters for depositing the first metal layer on one side of the polymer layer in the evaporation coating process are as follows: wire feed speed 300 mm / min, evaporation boat current 900 A, unwinding tension 150 N, winding tension 120 N, and coating vacuum degree 4*10 -3 pa, with a production speed of 20m / min; S2. The polymer layer is divided into an electrode region, an electrode tab region, and a transition region between the electrode region and the electrode tab region. From the other side of the polymer layer, circular holes with a diameter of 200 μm are laser-cut at intervals in the electrode tab region, with a spacing of 1 mm between adjacent circular holes. At the same time, from the other side of the polymer layer, micropores with a diameter of 80 μm are laser-cut at intervals in the electrode region, with a spacing of 1 mm. From the other side of the polymer layer, gradient circular holes are laser-cut at intervals in the transition region, with the gradient circular holes gradually increasing in size from the electrode region to the electrode tab region, namely 100 μm, 120 μm, 140 μm, 160 μm, and 180 μm respectively, and a spacing of 200 μm between adjacent gradient circular holes. Then, aluminum is deposited in the circular holes using an electroplating process to serve as electrodes, so that the first metal layer and the second metal layer are connected through the aluminum. At the same time, aluminum is deposited in the gradient circular holes in the transition region using the same electroplating process as the circular hole pore parameters. The process parameters for depositing metallic aluminum in the circular holes of the tab area using electroplating as a gradient of circular holes in the tab and transition area are as follows: total current is 3500A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min; the thickness of the tab is equal to the thickness of the polymer layer. S3. An aluminum layer is deposited on the other side of the polymer layer as a second metal layer using an evaporation coating process. The thickness of the second metal layer is 1000 nm. At the same time, aluminum is also deposited in the micropores of the electrode area using an evaporation coating process with the same parameters as the second metal layer, so as to obtain a high-performance composite current collector for the positive electrode. The process parameters for the evaporation coating process, which involves depositing a second metal layer on the other side of the polymer layer and depositing aluminum in the micropores of the electrode area, are as follows: wire feed speed 300 mm / min, evaporation boat current 900 A, unwinding tension 150 N, winding tension 120 N, and coating vacuum degree 4*10. -3 pa, with a production speed of 20m / min.

[0074] Example 7 A method for preparing a high-performance composite current collector with a negative electrode includes the following steps: S1. Using a PP film material with a thickness of 4.5um as the polymer layer, a copper layer is deposited on one side of the polymer layer as the first seed layer using a vacuum magnetron sputtering process. The thickness of the first seed layer is 50nm. Then, a copper layer is deposited on the first seed layer as the first metal layer using an electroplating process. The thickness of the first metal layer is 1000nm. The process parameters for depositing the first seed layer on one side of the polymer layer using vacuum magnetron sputtering are as follows: argon flow rate 120 sccm, single target power 15 kW, unwinding tension 100 N, winding tension 80 N, and coating vacuum degree 6.0*10 - 4 pa, with a production speed of 20m / min; The process parameters for depositing the first metal layer on the first seed layer using electroplating are as follows: total current is 2500A, anti-oxidation current is 3A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min. S2, such as Figure 3 As shown, the polymer layer is divided into an electrode region 01, an electrode tab region 03, and a transition region 02 located between the electrode region 01 and the electrode tab region 03. Rectangular channels with a width of 6 mm and a length of 8 mm are laser-cut at intervals in the electrode tab region from the other side of the polymer layer, and the rectangular channels are extended to the transition region 02. At the same time, micropores with a diameter of 50 μm and a spacing of 1 mm are laser-cut at intervals in the electrode region 01 from the other side of the polymer layer. Gradient circular holes are laser-cut at intervals in the transition region 02 from the other side of the polymer layer. The gradient circular holes gradually increase in size from the electrode region 01 to the electrode tab region 03, and are 80 μm, 110 μm, 140 μm, and 170 μm respectively. The spacing between adjacent circular holes is 200 μm. The processing position of the gradient circular holes is the gap position between the rectangular channels. Then, a water electroplating process is used to deposit metallic copper in the rectangular channel in the tab region and extending to the transition region. The metallic copper deposited in the rectangular channel in the tab region serves as the tab, so that the first metal layer and the second metal layer are connected through metallic copper. At the same time, a water electroplating process with the same parameters as the rectangular channel is used to deposit metallic copper in the gradient circular holes in the transition region. The process parameters for depositing metallic copper in the tab area and the rectangular channels extending to the transition area and the gradient circular holes in the transition area using electroplating are as follows: total current is 3500A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min; the thickness of the tab is equal to the thickness of the polymer layer. Figure 3 In the middle, the area with only black circles is the electrode area 01, the area with black circles and orange rectangles is the transition area 02, and the area with only orange rectangles is the electrode area 03. S3. Copper is deposited on the other side of the polymer layer as a second seed layer using vacuum magnetron sputtering. At the same time, copper is also deposited in the micropores of the electrode area using vacuum magnetron sputtering with the same parameters as the second seed layer. The thickness of the second seed layer is 50 nm. Copper is also deposited in the micropores of the electrode area using vacuum magnetron sputtering with the same parameters as the second seed layer. Then, copper is deposited on the second seed layer as a second metal layer using electroplating. The thickness of the second metal layer is 1000 nm, resulting in a high-performance composite current collector for the negative electrode. The process parameters for depositing a second seed layer on the other side of the polymer layer and depositing copper in the micropores of the electrode region using vacuum magnetron sputtering are as follows: argon flow rate 80 sccm, single target power 25 kW, unwinding tension 150 N, winding tension 150 N, and coating vacuum degree 8.0*10 -4 pa, with a production speed of 20m / min; The process parameters for depositing the second metal layer on the second seed layer using electroplating are as follows: total current is 2000A, anti-oxidation current is 3A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min.

[0075] Example 8 A method for preparing a high-performance composite current collector with a positive electrode includes the following steps: S1. Using a 6µm thick PET film as the polymer layer, an aluminum layer is deposited on one side of the polymer layer as the first metal layer using an evaporation coating process. The thickness of the first metal layer is 1000nm. The process parameters for depositing the first metal layer on one side of the polymer layer in the evaporation coating process are as follows: wire feed speed 300 mm / min, evaporation boat current 900 A, unwinding tension 150 N, winding tension 120 N, and coating vacuum degree 4*10 -3 pa, with a production speed of 20m / min; S2. Divide the polymer layer into an electrode region 01, an electrode tab region 03, and a transition region 02 located between the electrode region 01 and the electrode tab region 03. From the other side of the polymer layer, use laser cutting to process rectangular channels with a width of 6 mm and a length of 8 mm at intervals in the electrode tab region, and extend the rectangular channels to the transition region 02. At the same time, from the other side of the polymer layer, use laser cutting to process micropores at intervals in the electrode region 01. The micropores are circular holes with a diameter of 50 μm and a spacing of 1 mm. From the other side of the polymer layer, use laser cutting to process gradient circular holes at intervals in the transition region 02. The gradient circular holes gradually increase in size from the electrode region 01 to the electrode tab region 03, and are 80 μm, 110 μm, 140 μm, and 170 μm respectively. The spacing between adjacent circular holes is 200 μm. The processing position of the gradient circular holes is the gap position between the rectangular channels. Then, an electroplating process is used to deposit metallic aluminum in rectangular channels extending from the tab region to the transition region. The metallic aluminum deposited in the rectangular channels of the tab region serves as the tab, allowing the first metal layer and the second metal layer to be connected through the metallic aluminum. At the same time, a electroplating process with the same parameters as the rectangular channels is used to deposit metallic aluminum in the gradient circular holes of the transition region. The process parameters for depositing metallic aluminum in the tab area and the rectangular channels extending to the transition area and the gradient circular holes in the transition area using electroplating are as follows: total current is 3500A, unwinding tension is 120N, winding tension is 110N, and production speed is 5m / min; the thickness of the tab is equal to the thickness of the polymer layer. S3. An aluminum layer is deposited on the other side of the polymer layer as a second metal layer using an evaporation coating process. The thickness of the second metal layer is 1000 nm. At the same time, aluminum is also deposited in the micropores of the electrode area using an evaporation coating process with the same parameters as the second metal layer, so as to obtain a high-performance composite current collector for the positive electrode. The process parameters for the evaporation coating process, which involves depositing a second metal layer on the other side of the polymer layer and depositing aluminum in the micropores of the electrode area, are as follows: wire feed speed 300 mm / min, evaporation boat current 900 A, unwinding tension 150 N, winding tension 120 N, and coating vacuum degree 4*10. -3 pa, with a production speed of 20m / min.

[0076] Comparative Example 1 A method for preparing a common composite current collector for negative electrodes includes the following steps: S1. Using a PP film material with a thickness of 4.5 μm as the polymer layer, a copper layer is deposited on both sides of the polymer layer as the first seed layer and the second seed layer respectively using a vacuum magnetron sputtering process. The thickness of the first seed layer and the second seed layer is 50 μm. Then, a copper layer is deposited on the first seed layer and the second seed layer respectively as the first metal layer and the second metal layer using an electroplating process. The thickness of the first metal layer and the second metal layer is 1 μm, thus obtaining a negative electrode ordinary composite current collector. The process parameters for vacuum magnetron sputtering are as follows: argon flow rate 100 sccm, single target power 25 kW, unwinding tension 150 N, winding tension 150 N, and coating vacuum degree 3*10. -3 pa, with a production speed of 20m / min; The process parameters for electroplating using water are as follows: total current is 3000A, anti-oxidation current is 3A, unwinding tension is 40~120N, winding tension is 110N, and production speed is 5m / min.

[0077] Comparative Example 2 A method for preparing a conventional negative electrode current collector includes the following steps: S1. Place a 6µm thick copper foil into a coating machine and coat it onto a copper plate to form a thin film. Peel the coated copper foil off the copper plate to separate the copper foil from the copper plate. Place the copper foil into a cleaning tank to clean impurities and dirt. After baking and slitting, the copper foil is formed into the required width to obtain the negative electrode conventional current collector.

[0078] Comparative Example 3 A method for preparing a common composite current collector with a positive electrode includes the following steps: S1. Using a 6µm thick PET film as the polymer layer, an aluminum layer is deposited on both sides of the polymer layer as the first metal layer and the second metal layer respectively using a vacuum evaporation process. The thickness of the first metal layer and the second metal layer is 1µm, thus obtaining a positive electrode ordinary composite current collector. The process parameters for vacuum evaporation are as follows: wire feed speed 200 mm / min, evaporation boat current 900 A, unwinding tension 150 N, winding tension 120 N, and coating vacuum degree 4*10. -3 pa, with a production speed of 20m / min.

[0079] Comparative Example 4 A method for preparing a conventional positive electrode current collector includes the following steps: S1. Place an 8µm thick aluminum foil into a coating machine and coat it onto an aluminum plate to form a thin film. Peel the coated aluminum foil off the aluminum plate to separate it from the aluminum plate. Place the aluminum foil into a cleaning tank to clean impurities and dirt. After baking and slitting, aluminum foil of the required width is formed to obtain the positive electrode conventional current collector.

[0080] Detection and Analysis 1) Peel force test Peel force tests were performed on the negative high-performance composite current collectors prepared in Examples 1 to 3 and 7, the positive high-performance composite current collectors prepared in Examples 4 to 6 and 8, the negative ordinary composite current collectors prepared in Comparative Example 1, and the positive ordinary composite current collectors prepared in Comparative Example 3.

[0081] The specific operation was as follows: A Labthink tensile puncture machine (model: C610H) was used to test the peel force between the adhesive layer and the metal layer. The sample size was 15mm*200mm. 3M-9448A double-sided tape was attached to a 30mm*50mm steel plate. One end of the sample to be tested was then evenly attached to the double-sided tape. A 2kg standard roller was used to roll back and forth 3 times. The pressed sample was then placed on the tensile testing machine and peeled at 180 degrees. The speed was set to 50mm / min and the running distance was 100mm. The maximum value was taken. The peel force test results of the electrode area are shown in Table 1.

[0082] Table 1 shows the peel strength test results Analysis from Table 1 shows that there is little difference in peeling between Example 1 and Comparative Example 1, and between Example 4 and Comparative Example 3 in the electrode area. There is a significant improvement in the peel strength in the electrode area for Example 2, 3, 7 and Comparative Example 1, and for Example 5, 6, 8 and Comparative Example 3. This indicates that the microporous structure in the electrode area improves the adhesion between the metal layer and the polymer layer base film, thereby enhancing the overall strength of the composite current collector and reducing the potential failure probability of the product.

[0083] 2) Success rate test of direct ultrasonic welding of tabs The negative high-performance composite current collectors prepared in Examples 1 to 3 and Example 7, the positive high-performance composite current collectors prepared in Examples 4 to 6 and Example 8, the negative ordinary composite current collector prepared in Comparative Example 1, and the positive ordinary composite current collector prepared in Comparative Example 3 were respectively tested for the success rate of direct ultrasonic welding of tabs with 100 samples each.

[0084] The specific operation steps are as follows: The tab areas of 10 negative high-performance composite current collectors prepared in Example 1 were stacked and welded in sequence (this is one sample), and ultrasonic welding was used for welding. The welding pressure was 0.35 Mpa, the welding frequency was 35 Kz, and the welding time was 0.3 s. During welding, the ultrasonic welding energy directly acted on the surface of the first layer and the surface of the last layer. After welding, visual inspection, tensile test, and resistance test were carried out. The same procedure was followed for the other examples.

[0085] Visual confirmation: No missed welding, false welding, or poor welding is considered qualified.

[0086] Tensile test: The welded tabs were subjected to a tensile test. A minimum tensile threshold of 50 N was set as qualified to ensure that the welding strength meets the standard.

[0087] Resistance test: Measure the contact resistance at the welding point. The smaller the resistance value, the closer the welding. A resistance ≤ 5 mΩ was set as qualified.

[0088] If all of the visual confirmation, tensile test, and resistance test are qualified, it indicates successful welding. The results are shown in Table 2. Among them, the tab welding success rate of Example 1 in Table 2 is 93%, which means that 93 out of 100 samples were successfully welded. The same procedure was followed for the other examples.

[0089] Table 2 shows the success rate test results of direct ultrasonic welding of tabs As shown in Table 2, the welding success rate of the tabs in existing composite current collectors is 0%. This is because the polymer layer in the middle of existing composite current collectors is an insulating material, making direct welding of the tabs impossible. The composite current collector obtained through the technical solution of this invention, by setting a metal conductive area in the tab region, allows direct welding of the tab region of the composite current collector and achieves a good tab welding success rate.

[0090] 3) Battery performance testing Example 3 was used as the negative electrode current collector, Comparative Example 4 and Example 6 were used as the positive electrode current collectors, Example 1 was used as the negative electrode current collector, Example 4 was used as the positive electrode current collector, Example 2 was used as the negative electrode current collector, Example 5 was used as the positive electrode current collector, Example 7 was used as the negative electrode current collector, Example 6 was used as the positive electrode current collector, Example 3 was used as the negative electrode current collector, Example 8 was used as the positive electrode current collector, Example 7 was used as the negative electrode current collector, Example 8 was used as the positive electrode current collector, Comparative Example 2 was used as the negative electrode current collector, Example 8 was used as the positive electrode current collector, and Comparative Example 2 was used as the negative electrode current collector, Example 6 and Comparative Example 4 were used as the positive electrode current collectors. The positive electrode used ternary material NCM523 as the positive electrode active material, the negative electrode used graphite as the negative electrode active material, polyvinylidene fluoride was used as the binder, lithium hexafluorophosphate was used as the electrolyte, and 8µm polyolefin was used as the separator. The outer film was aluminum-plastic film, and they were assembled into soft-pack lithium-ion batteries.

[0091] Test 1: Rate performance and cycle life performance of the prepared soft-pack lithium-ion battery. Rate performance test conditions: Tested at room temperature 25℃, voltage range 0~3V, and current of 1C and 5C. Cycle life test conditions: The test was conducted at room temperature of 25℃, voltage range of 0~3V, and current of 1C; the test results are shown in Table 3.

[0092] Table 3 shows the test results for battery rate performance and cycle life performance. As can be seen from the analysis of Table 3, the stability of the battery prepared in the example is significantly improved under high current density. This is because the composite current collector has a polymer base film in the middle, which has a higher elongation rate than the traditional current collector. It can recover quickly after deformation during charging and discharging, thereby improving the stability and cycle life of the battery.

[0093] Test 2: Energy density test of the prepared soft-pack lithium-ion battery The battery energy density test was conducted in accordance with the test method of GB / T 18287-2013 "Lithium-ion Battery Pack". Twenty soft-pack lithium-ion batteries were prepared for testing, and the energy density was taken as the average value. The results are shown in Table 4.

[0094] Table 4 shows the battery energy density test results (average). As can be seen from the analysis of Table 4, the battery prepared by the traditional current collector has the lowest energy density, while the composite current collector obtained by the technical solution of the present invention has the highest energy density, indicating that the technical solution of the present invention has a significant improvement in battery energy density.

[0095] 4) Puncture test The specific operating steps are as follows: Fully charge the prepared soft-pack lithium-ion single cell battery, use a Labthink tensile puncture machine (model: C610H), with a Ф3mm needle tip cone angle of 45~60 degrees, and no corrosion, oxide layer, oil stains, etc. on the surface, at a speed of 25mm / s, to penetrate from the direction perpendicular to the test piece, and the steel needle stays in the battery. Prepare 20 batteries respectively, observe for 5 minutes and record the fire rate. The test results are shown in Table 5.

[0096] Table 5 shows the results of the puncture test. As can be seen from the analysis of Table 5, batteries made with traditional copper foil and aluminum foil will catch fire 100% of the time, batteries made with traditional copper foil or aluminum foil and composite copper foil or aluminum foil have a probability of catching fire, and batteries made with composite current collectors do not catch fire. This shows that the batteries made with composite current collectors obtained by using the technical solution of this invention have excellent thermal runaway performance.

[0097] In summary, the high-performance composite current collector of this invention effectively solves the problem of existing composite current collectors being unable to directly weld external electrodes by dividing the polymer layer into a tab region and an electrode plate region, setting channels in the tab region and filling the channels with conductive material, allowing the conductive material to be directly used as the tab for welding external electrodes. This also increases the conductivity of the tab and the welding area, avoiding the problem of poor soldering caused by poor contact during traditional tab welding. Simultaneously, by processing micropores in the electrode plate region and depositing the same metal material as the second metal layer in the micropores, electronic conduction on both sides of the composite current collector is effectively achieved under normal operating conditions, reducing the battery's DC internal resistance, thereby reducing localized heat generation and improving conductivity and safety. The metal material in the microporous structure allows the metal layers on both sides of the polymer layer to be connected together in an I-shaped structure, thus interlocking the polymer layer and the two metal layers into a whole. The interconnection of the two metal layers effectively improves the adhesion between the metal layer and the polymer layer, reduces the difference in expansion and contraction between them, and thus improves the overall strength.

[0098] The present invention discloses a method for preparing a high-performance composite current collector. By depositing metal layers on both sides of a polymer layer and depositing conductive material in the channels to serve as tabs, it effectively solves the problem that existing composite current collectors cannot be directly welded to external tabs. Depositing a first metal layer on one side of the polymer layer provides a good conductive foundation for the current collector. Then, processing channels and depositing conductive material on the other side to serve as tabs not only increases the conductivity and welding area of ​​the tabs but also avoids the problem of poor soldering caused by poor contact during traditional tab welding. Depositing a second metal layer on the other side of the polymer layer further enhances the overall strength and conductivity of the current collector, effectively preventing wrinkles, cracks, or fractures during welding, improving welding strength and reliability, and thus significantly improving the performance and service life of the composite current collector. This method has significant application value in the field of lithium-ion battery technology.

[0099] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A high-performance composite current collector, characterized in that, It includes a polymer layer, a first metal layer disposed on one side of the polymer layer, and a second metal layer disposed on the other side of the polymer layer; The polymer layer has at least a polar plate region and a tab region; A channel is formed in the tab region of the polymer layer, and the channel is filled with a conductive material, so that the first metal layer and the second metal layer are connected through the conductive material. Micropores are formed in the electrode region of the polymer layer, and the micropores are filled with the same metal material as the second metal layer, so that the first metal layer and the second metal layer are connected through the metal material in the micropores.

2. The high performance composite current collector of claim 1, wherein, The polymer layer has an electrode region, a tab region, and a transition region between the electrode region and the tab region; the transition region has gradient micropores filled with conductive material to improve the conductivity of the transition region and reduce heat generation.

3. The high performance composite current collector of claim 2, wherein, The gradient micropores are gradient micropores whose pore size gradually increases from the electrode region to the tab region; And / or, the channel of the tab region extends to the transition region, so that the conductive material in the channel is directly connected to the first metal layer and the second metal layer of the electrode region; And / or, the channels in the tab region are the entire tab region, a rectangular structure formed at intervals, a triangular structure formed at intervals, or a pore formed at intervals; And / or, a first seed layer is provided between the polymer layer and the first metal layer; And / or, a second seed layer is provided between the polymer layer and the second metal layer; And / or, the thickness of the polymer layer is 2~10 μm; And / or, the thickness of the first metal layer is 0.5~3µm; And / or, the thickness of the second metal layer is 0.5~3µm; And / or, the thickness of the high-performance composite current collector is 3~16µm; And / or, the material of the polymer layer is selected from at least one of polyethylene terephthalate, polypropylene, polyethylene and polyimide.

4. A method of making a high performance composite current collector, characterized by, Includes the following steps: S1. Deposit a first metal layer on one side of the polymer layer; S2. Process pores from the other side of the polymer layer, and then deposit conductive material in the pores to serve as tabs; S3. Deposit a second metal layer on the other side of the polymer layer to obtain a high-performance composite current collector.

5. The method of making a high performance composite current collector of claim 4, wherein, S1 includes: depositing a first seed layer on one side of the polymer layer, and then depositing a first metal layer on the first seed layer; S3 includes: depositing a second seed layer on the other side of the polymer layer, and then depositing a second metal layer on the second seed layer to obtain a high-performance composite current collector.

6. The method of making a high performance composite current collector of claim 5, wherein, S1 includes: depositing a first seed layer on one side of a polymer layer using a vacuum magnetron sputtering process, and then depositing a first metal layer on the first seed layer using an electroplating process. S2 includes: dividing the polymer layer into an electrode region and an electrode tab region; processing a channel in the electrode tab region from the other side of the polymer layer using a laser cutting or punching process; and then depositing a conductive material in the channel using an electroplating process to serve as an electrode tab, so that the first metal layer and the second metal layer are connected through the conductive material. S3 includes: depositing a second seed layer on the other side of the polymer layer using a vacuum magnetron sputtering process, and then depositing a second metal layer on the second seed layer using an electroplating process to obtain a high-performance composite current collector.

7. The method of making a high performance composite current collector of claim 6, wherein, S2 further includes: processing micropores in the electrode area from the other side of the polymer layer using laser cutting or punching processes; S3 further includes: while depositing a second metal layer on the other side of the polymer layer, depositing the same metal material as the second metal layer in the micropores processed in the electrode region to obtain a high-performance composite current collector.

8. The method of making a high performance composite current collector of claim 4, wherein, S2 includes: dividing the polymer layer into an electrode region, an electrode tab region, and a transition region located between the electrode region and the electrode tab region; A channel is processed in the tab area from the other side of the polymer layer using laser cutting or punching process, and then a conductive material is deposited in the channel using electroplating process to serve as a tab, so that the first metal layer and the second metal layer are connected through the conductive material. Micropores are processed in the electrode area from the other side of the polymer layer using laser cutting or punching processes. From the other side of the polymer layer, a gradient micropore with gradually increasing pore size from the electrode area to the tab area is processed in the transition zone using laser cutting or punching technology. Then, a conductive material is deposited in the gradient micropore using an electroplating process. S3 includes: while depositing a second metal layer on the other side of the polymer layer, depositing the same metal material as the second metal layer in the micropores processed in the electrode region to obtain a high-performance composite current collector; And / or, S1 includes: depositing a first metal layer on one side of the polymer layer using an evaporation deposition process; S3 includes: depositing a second metal layer on the other side of the polymer layer using an evaporation coating process to obtain a high-performance composite current collector.

9. A pole piece characterized by, The current collector of the electrode is selected from... The high-performance composite current collector according to any one of claims 1 to 3, or the high-performance composite current collector prepared by the preparation method according to any one of claims 4 to 8.

10. A battery, characterized by The electrode of the battery is the electrode as described in claim 9.

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