Composite current collector production process and composite current collector

Abstract

The invention provides a composite current collector production process and a composite current collector. The production process of the composite current collector comprises the steps that a base film layer and a conductive layer are compounded, the base film layer and the conductive layer are compounded through an adhesive layer to form a composite film, the composite film is provided with a tab area and a non-tab area along the surface of the composite film, and the tab area is located on the side edge of the non-tab area; the conductive layer is corroded, and the thickness of the conductive layer is integrally reduced in an etching mode; the electrode layer is compounded on the outer side, away from the base film layer, of the conducting layer; tearing off the film, namely tearing off the base film layer and / or the adhesive layer in the tab region; and tab pressing: pressing the conductive layers on the two sides of the tab region on a plane. According to the invention, the problem that the production process of the composite current collector in the prior art is complicated is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a composite current collector production process and a composite current collector. Background Art

[0002] As battery aging causes the growth of metal dendrites, with the increase in the number of cycles and the induction of impurity particles mixed in during the production process, sharp objects such as lithium dendrites formed by adverse side reactions can easily pierce the diaphragm, causing microscopic internal short circuits. Internal short circuits caused by mechanical damage are generally caused by the battery being squeezed / punctured during a car collision. The polymer flexible substrate in the composite current collector has good softness and ductility, can absorb part of the stress, and is not easy to break; at the same time, it can release the compressive stress generated during the deposition of metallic lithium, thereby effectively controlling the generation of dendrites and preventing puncture from causing internal short circuits. The polymer substrate in the middle of the composite current collector has flame retardant properties, and its metal conductive layer is relatively thin. When short-circuited, it will melt like a fuse and melt quickly before thermal runaway. Battery damage is limited to the puncture site to form a "point break". The thermal short-circuit effect of the composite current collector can control the thermal runaway of the battery. Therefore, the composite current collector can effectively avoid internal short circuits.

[0003] There is an existing scheme, in the length direction of the support body, the support film includes an insulating part and a conductive part, wherein the composite current collector includes a non-ear area and an ear area in the length direction, the insulating part is in the non-ear area, and the conductive part is in the ear area. The above arrangement method makes the production process of the current collector more complicated and the cost higher due to the addition of the conductive part, and the conductive part is a non-metallic material, and its reliability needs to be verified due to the influence of the formula and the use environment.

[0004] Meanwhile, existing solutions generally use physical vapor deposition technology (vacuum sputtering coating, vacuum ion coating, vacuum evaporation coating, etc.) and / or chemical vapor deposition technology to deposit a metal and / or non-metal surface treatment layer on the surface of the support film prepared in the step. However, due to the high cost of metal foil additive manufacturing, its economic efficiency is poor. Summary of the invention

[0005] The main purpose of the present invention is to provide a composite current collector production process and a composite current collector to solve the problem of complex process of the composite current collector production process in the prior art.

[0006] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a composite current collector production process is provided, including: compounding a base film layer with a conductive layer, the base film layer is compounded with the conductive layer through an adhesive layer to form a composite film, along the surface of the composite film, the composite film has a pole lug area and a non-pole lug area, and the pole lug area is located on the side of the non-pole lug area; corroding the conductive layer, the thickness of the conductive layer is reduced as a whole by etching; compounding the electrode layer, the electrode layer is compounded on the outer side of the conductive layer away from the base film layer; tearing the film, tearing off the base film layer and / or the adhesive layer in the pole lug area; and pressing the pole lugs, pressing the conductive layers on both sides of the pole lug area onto a plane.

[0007] Furthermore, the base film layer and the conductive layer are composited including: unwinding the base film roll, and processing a pre-tear structure on the side of the base film layer during the unwinding process, wherein the pre-tear structure is located at the boundary between the pole lug area and the non-pole lug area, or is offset from the boundary between the pole lug area and the non-pole lug area to the non-pole lug area by a predetermined distance, and avoids the pressing position of the pole lug.

[0008] Furthermore, the base film layer and the conductive layer are composited including: preparing an adhesive, mixing a multi-component mixed hardening adhesive in a predetermined ratio by a screw pump to obtain a target adhesive solution, and weighing them before and after mixing to verify the mixing ratio to obtain a consistent adhesive solution.

[0009] Furthermore, the composite of the base film layer and the conductive layer also includes: unwinding the base film roll, unwinding the base film roll after the adhesive is prepared; coating the base film layer with glue, transferring the mixed glue to the base film layer through a concave roller to form an adhesive layer; unwinding the conductive layer roll, unwinding the conductive layer roll, and keeping the tension of the conductive layer roll in the conveying direction and the transverse direction perpendicular to the conveying direction the same during unwinding; composite, composite the conductive layer on the base film layer to form a composite film; baking and curing, conveying the composite film after composite into an oven for baking; and rolling up the composite film, rolling up the baked composite film, and unloading it.

[0010] Furthermore, the composite of the base film layer and the conductive layer also includes: when the base film layer is coated with glue, the thickness of the mixed glue on the base film layer is 0.2-1.0 microns; during baking and curing, the oven temperature of the oven is 50-200 degrees Celsius and the conveying speed is 5-200m / min.

[0011] Furthermore, the composite of the base film layer and the conductive layer also includes: for a composite film having a multi-component adhesive formula, a second vacuum baking is performed after baking and curing, and the composite film is again transported to the oven for a second vacuum baking, the oven temperature is 50-200°C, and the baking time is 1H-48H to ensure that the small molecules of the two-component adhesive are completely reacted.

[0012] Furthermore, the composite of the base film layer and the conductive layer also includes: the adhesive layer includes a tab adhesive portion and a non-tab adhesive portion, the tab adhesive portion is located in the tab region, the non-tab adhesive portion is located in the non-tab region, and there is a gap between the tab adhesive portion and the non-tab adhesive portion.

[0013] Furthermore, the conductive layer corrosion includes: preparing an etching medium, mixing solid sodium hydroxide and pure water to obtain an etching solution of a predetermined proportion as an etching medium, or using a corrosive gas as an etching medium; unwinding a composite film, unwinding a composite film obtained by compounding a base film layer and a conductive layer, and making the composite film pattern flat after unwinding; thinning the conductive layer, spraying the etching medium onto the surface of the conductive layer, and obtaining a conductive layer of a target thickness after reaction; cleaning the composite film, removing surface impurities from the composite film by pure water spraying, baking, or clean gas cleaning, and then obtaining a composite film with a clean and tidy surface by rapid baking; and rolling up the composite film, rolling up the composite film, and making the composite film pattern flat after rolling up.

[0014] Furthermore, the conductive layer corrosion also includes: when the conductive layer is thinned, the target thickness is 1-3.5 microns, and the error of the target thickness is within 1 micron.

[0015] Furthermore, the conductive layer corrosion also includes etching medium recovery, which includes: when the etching medium is an etching liquid, adding excess aluminum ingots or aluminum wires to the reacted etching liquid so that the sodium hydroxide solution is completely reacted, and the solution after the reaction is dried or evaporated to obtain sodium aluminate solid.

[0016] Furthermore, the electrode layer composite includes: electrode layer preparation, pre-treating the electrode material of the electrode layer according to the lithium battery production process requirements to meet the composite requirements; composite film unwinding, unwinding the composite film, and making the composite film pattern flat after unwinding; pole piece coating baking or composite, distributing the electrode material evenly on the composite film by coating, and forming an electrode layer on the outside of the composite film; rolling, rolling according to the lithium battery production process requirements.

[0017] Furthermore, the film tearing includes: stripping, after rolling, the electrode layer is cut according to the requirements of the electrode layer size, and an elastic pad is laid under the cutting knife to ensure the stripping effect of the unbonded area; tearing, after stripping, the composite film is pulled to the pre-tear structure of the base film layer, and the base film layer in the tab area is torn off.

[0018] Furthermore, the tab pressing includes: when pressing the tab, at least one of cold pressing of the reinforcement rib or ultrasonic roller welding is used for pressing.

[0019] According to another aspect of the present invention, a composite current collector is provided, comprising: a base film layer; a plurality of conductive layers, the conductive layers being composited on opposite sides of the base film layer via an adhesive layer, the orthographic projection of the base film layer on the conductive layer being located within the range of the conductive layer, a pole lug region and a non-pole lug region being provided between the conductive layers, the base film layer being located within the non-pole lug region and outside the pole lug region, the conductive layers on both sides of the pole lug region being pressed together to form a pole lug; and an electrode layer, the electrode layer being composited on the outer side of the conductive layer away from the base film layer.

[0020] Further, the orthographic projection of the electrode layer on the conductive layer is located within the range of the conductive layer.

[0021] Furthermore, the orthographic projection of the adhesive layer on the base film layer is located within the range of the base film layer.

[0022] By applying the technical solution of the present invention and adopting the above-mentioned process method, the overall process is as follows: the base film layer is divided into a non-ear area and an ear area along the length direction, and a conductive layer of a specified thickness is compounded on both sides of the base film layer by forming an adhesive layer with a specified adhesive, and then the conductive layer is etched to the required thickness by a chemical or electrochemical corrosion method. After the electrode layer is compounded, the base film layer in the ear area is removed by an automated device and then the ear is pressed. In this way, since there is no need for structures such as a conductive part, the complexity of the composite current collector production process is greatly reduced, and the product reliability is higher. And since the conductive layer is thinned by etching, the production and processing cost is lower, so the economy is better. The above-mentioned setting method solves the high cost problem of additive manufacturing of composite current collectors and the problem of conductive layers on both sides of the polymer base film in the prior art, and formulates a batch production process in combination with the actual electrode production process, realizing low-cost, large-scale, high-quality processing and production. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0024] Figure 1 The overall flow chart of the composite current collector production process of the present invention is shown;

[0025] Figure 2 A flow chart showing the composite of the base film layer and the conductive layer is shown;

[0026] Figure 3 A flow chart showing corrosion of the conductive layer is shown;

[0027] Figure 4 The flow chart of electrode layer compounding, film tearing and tab pressing is shown;

[0028] Figure 5A schematic diagram showing the structure of the composite current collector of the present invention when the base film layer and the conductive layer are composited;

[0029] Figure 6 A schematic diagram of the structure of the composite current collector when the conductive layer is corroded is shown;

[0030] Figure 7 A schematic diagram showing the structure of the composite current collector when it is composited with the electrode layer;

[0031] Figure 8 The schematic diagram of the structure of the composite electrode when the film is torn off is shown;

[0032] Fig. 9 The schematic diagram shows the structure of the composite electrode after the slitting and electrode pressing are completed.

[0033] The above drawings include the following reference numerals:

[0034] 10. Base film layer; 11. Tab area; 12. Non-tab area; 13. Pre-tear structure; 20. Adhesive layer; 30. Conductive layer; 40. Electrode layer. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs.

[0037] In the present invention, unless otherwise specified, the directional words used, such as "up, down, top, bottom", usually refer to the directions shown in the drawings, or to the components themselves in the vertical, perpendicular or gravity directions; similarly, for ease of understanding and description, "inside and outside" refer to the inside and outside relative to the outline of each component itself, but the above-mentioned directional words are not used to limit the present invention.

[0038] In order to solve the problem of complex process of composite current collector production in the prior art, the present invention provides a composite current collector production process and a composite current collector.

[0039] like Figures 1 to 4A composite current collector production process shown includes: compounding of a base film layer and a conductive layer, wherein the base film layer 10 is compounded with a conductive layer 30 through an adhesive layer 20 to form a composite film, wherein the composite film has a pole lug region 11 and a non-pole lug region 12 along the surface of the composite film, and the pole lug region 11 is located on the side of the non-pole lug region 12; corrosion of the conductive layer, wherein the thickness of the conductive layer 30 is reduced as a whole by etching; compounding of the electrode layer, wherein the electrode layer 40 is compounded on the outer side of the conductive layer 30 away from the base film layer 10; tearing off the film, wherein the base film layer 10 and / or the adhesive layer 20 in the pole lug region 11 is torn off; and pressing of the pole lugs, wherein the conductive layers 30 located on both sides of the pole lug region 11 are pressed onto a plane.

[0040] This embodiment adopts the above-mentioned process method, and the overall process is as follows: the base film layer 10 is divided into a non-ear area 12 and an ear area 11 along the length direction, and a conductive layer 30 of a specified thickness is compounded on both sides of the base film layer 10 by forming an adhesive layer 20 with a specified adhesive, and then the conductive layer 30 is etched to the required thickness by a chemical or electrochemical corrosion method. After the electrode layer 40 is compounded, the base film layer 10 in the ear area 11 is removed by an automated device and then the ear is pressed. In this way, since there is no need for structures such as a conductive part, the complexity of the composite current collector production process is greatly reduced, and the product reliability is higher. And since the conductive layer 30 is thinned by etching, the production and processing cost is lower, so the economy is better. The above-mentioned setting method solves the high cost problem of additive manufacturing of composite current collectors and the problem of conductive layers on both sides of the polymer base film in the prior art, and formulates a batch production process in combination with the actual electrode production process, realizing low-cost, large-scale, high-quality processing and production.

[0041] In this embodiment, the tab regions 11 are disposed on both sides of the non-tab region 12, thereby forming a "one out of two" structure. Of course, the tab region 11 may also be disposed on only one side.

[0042] In this embodiment, the base film layer and the conductive layer are composited, including: unwinding the base film roll, and processing a pre-tear structure 13 on the side of the base film layer 10 during the unwinding process, the pre-tear structure 13 is located at the boundary between the pole lug area 11 and the non-pole lug area 12, or is offset from the boundary between the pole lug area 11 and the non-pole lug area 12 to the non-pole lug area 12 by a predetermined distance, and avoids the pressing position of the pole lug. Through the design of the pre-tear structure 13, the base film layer 10 and the adhesive layer 20 in the pole lug area 11 can be more convenient to tear off, ensuring accurate and reliable film tearing, avoiding excessive tearing or insufficient tearing, and ensuring processing quality.

[0043] Optionally, the pre-tear structure 13 can be in the form of a pre-tear notch or a pre-tear thinning area as required, as long as it is conducive to tearing off the base film layer 10 and the adhesive layer 20 in the tab area 11 during subsequent film tearing, so that the tab area 11 can form a cavity portion to ensure the subsequent tab pressing. The pre-tear structure 13 of this embodiment adopts a pre-tear notch, and its structure is simpler.

[0044] The compounding of the base film layer and the conductive layer of this embodiment also includes: before compounding the base film layer 10 and the conductive layer 30, first prepare the adhesive, and use a screw pump to mix the multi-component mixed hardening glue in a predetermined ratio to obtain a target glue solution, and the target glue solution is subsequently attached to the outside of the base film layer 10 to form an adhesive layer 20 to achieve adhesion with the conductive layer 30. The target glue solution is weighed before and after mixing, and the mixing ratio is verified to ensure that a consistent glue solution is obtained to ensure processing quality. The multi-component mixed hardening glue of this embodiment adopts a two-liquid mixed hardening glue of an acrylic acid or butyl system. More specifically, acrylic acid adopts acrylate, and the butyl system includes butyl rubber. Of course, hardening glues of other components can also be used.

[0045] The composite of the base film layer and the conductive layer in this embodiment also includes the processes of unwinding the base film roll, coating the base film layer, unwinding the conductive layer, composite, baking and curing, and composite film winding. Figure 2 and Figure 5 As shown, the overall process is as follows:

[0046] Adhesive preparation: Mix two liquids of acrylic or butyl system to harden the adhesive, i.e., A / B adhesive, in a predetermined ratio through a screw pump to obtain the target adhesive solution, and weigh them before and after mixing to verify the mixing ratio and obtain a consistent adhesive solution;

[0047] Base film layer unwinding and pre-tear processing: unwinding a base film roll of a determined width, completing the pre-tear production during the film feeding process, the pre-tear position is preferably set at the boundary between the pole ear area 11 and the non-pole ear area 12, and can also be offset from the boundary between the pole ear area 11 and the non-pole ear area 12 to the non-pole ear area 12 by a predetermined distance, and cannot exceed the subsequent pole ear welding weld mark position;

[0048] Gluing the base film layer: The mixed glue is transferred to the base film layer 10 through a micro-concave roller to form an adhesive layer 20. The thickness of the single-sided adhesive layer 20 is controlled to be 0.2-1.0 microns;

[0049] Conductive layer unwinding: The conductive layer roll is unwound at a certain speed. During unwinding, the tension of the conductive layer roll in the conveying direction and the cross-sectional direction perpendicular to the conveying direction, i.e., the MD / TD direction, is kept the same;

[0050] Composite: Composite the thicker conductive layer 30 onto the base film layer 10 to form a composite film;

[0051] Baking and curing: The composite film is transported to an oven with a temperature of 50-200 degrees Celsius and a conveying speed of 5-200 m / min.

[0052] Composite film winding: winding the baked composite film and unloading it;

[0053] Quality inspection: Test the appearance, size, pattern and performance of the composite film.

[0054] In particular, for composite films with multi-component adhesive formulas, the composite of the base film layer and the conductive layer in this embodiment also includes: secondary vacuum baking after baking and curing, and the composite film is again transported to the oven for secondary vacuum baking. The oven temperature is 50-200°C and the baking time is 1H-48H to ensure that the small molecules of the two-component adhesive are completely reacted to ensure product quality.

[0055] Preferably, the composite of the base film layer and the conductive layer further includes: the adhesive layer 20 includes a pole tab adhesive portion and a non-pole tab adhesive portion, the pole tab adhesive portion is located in the pole tab area 11, the non-pole tab adhesive portion is located in the non-pole tab area 12, and there is a gap between the pole tab adhesive portion and the non-pole tab adhesive portion.

[0056] The conductive layer corrosion of this embodiment includes the processes of preparing the etching medium, unwinding the composite film, thinning the conductive layer, cleaning the composite film, and winding the composite film. In this embodiment, sodium hydroxide solution is used as the etching medium. Figure 3 and Figure 6 As shown, the overall process of conductive layer corrosion is:

[0057] Preparation of etching medium: mixing and stirring sodium hydroxide solid and pure water to obtain an etching solution of a predetermined ratio as etching medium;

[0058] The composite film is unrolled, and the composite film obtained by combining the base film layer 10 and the conductive layer 30 is unrolled at a certain speed, and the composite film is made flat after unrolling;

[0059] The conductive layer is thinned, and the etching solution is evenly sprayed onto the surface of the conductive layer 30 to obtain a conductive layer 30 of target thickness after reaction. The target thickness is preferably 1-3.5 microns, and the error of the target thickness is within 1 micron;

[0060] Cleaning of composite membranes: removing surface crystallization impurities or other surface impurities by spraying or baking the composite membranes with pure water, and then quickly baking them to obtain a clean and tidy composite membrane;

[0061] Composite film rolling, rolling the composite film at a certain speed, and making the rolled composite film flat;

[0062] Quality inspection: Test the appearance, size, pattern and performance of the composite film.

[0063] In addition to the etching solution, the etching medium mentioned above can also be a corrosive gas. In this case, when cleaning the composite film, the surface impurities can be removed by cleaning with a clean gas.

[0064] The conductive layer corrosion of this embodiment also includes the recovery of etching medium, which includes: for the sodium hydroxide solution used in this embodiment, adding excessive aluminum ingots or aluminum wires to the etching solution after the reaction, so that the sodium hydroxide solution is completely reacted, and the solution after the reaction is dried or evaporated to obtain sodium aluminate solid, thereby realizing the recovery of the etching medium. When the etching medium uses corrosive gas, it can be recycled by the corresponding method of corrosive gas recovery.

[0065] The electrode layer compounding of this embodiment includes the processes of electrode layer preparation, composite film unwinding, electrode piece coating baking or compounding, rolling and the like. Figure 4 and Figure 7 As shown, the specific process is as follows:

[0066] Electrode layer preparation: pre-treating the electrode material of the electrode layer 40 according to the lithium battery production process requirements to meet the composite requirements;

[0067] Composite film unwinding: unwinding the composite film at a certain speed and making the composite film flat after unwinding;

[0068] The electrode piece is coated, baked or composited, and the electrode material is evenly distributed on the composite film by coating, and an electrode layer 40 is formed on the outside of the composite film;

[0069] Roll pressing is carried out according to the production process requirements of lithium batteries.

[0070] like Figure 4 and Fig. 9 As shown, after the electrode layer is laminated, the film can be peeled off. The film peeling includes striping and tearing off. The specific process is as follows:

[0071] Slitting: After rolling the composite electrode, the electrode layer 40 is cut according to the size requirements of the electrode layer 40. At the same time, during the slitting, an elastic pad is laid under the slitting knife to ensure the slitting effect of the unbonded area;

[0072] After tearing off, the composite film is pulled to the pre-tear structure 13 of the base film layer 10 after stripping, and the base film layer 10 or the adhesive layer 20 or both in the tab area 11 are torn off. When tearing off, care should be taken not to affect the appearance of the upper and lower conductive layers 30.

[0073] like Figure 4 and Fig. 9As shown, after the film is torn off, the tab pressing operation can be carried out. The tab pressing specifically includes: when pressing the tab, at least one of the reinforcement rib cold pressing or ultrasonic roller welding is used for pressing.

[0074] After the tabs are pressed together, the obtained composite current collector can be inspected for quality, that is, the appearance, size, format and performance of the electrode layer 40 can be tested, and then the composite current collector can be rolled up at a certain speed, thereby completing a whole set of processing procedures.

[0075] like Figures 5 to 9 As shown, this embodiment also provides a composite current collector, which is processed by the above-mentioned composite current collector processing technology. The composite current collector includes a base film layer 10, multiple conductive layers 30 and an electrode layer 40. The conductive layer 30 is composited on the opposite sides of the base film layer 10 through an adhesive layer 20. The orthographic projection of the base film layer 10 on the conductive layer 30 is located within the range of the conductive layer 30. There are a pole lug area 11 and a non-pole lug area 12 between the conductive layers 30. The base film layer 10 is located in the non-pole lug area 12 and outside the pole lug area 11. The conductive layers 30 on both sides of the pole lug area 11 are pressed together to form a pole lug; the electrode layer 40 is composited on the outer side of the conductive layer 30 away from the base film layer 10.

[0076] During the processing, both the tab area 11 and the non-tab area 12 will have an adhesive layer 20, so before tearing the film, the adhesive layer 20 of the present embodiment can be the same, so that the adhesive layers 20 of the tab area 11 and the non-tab area 12 are the same and connected as one. Of course, the adhesive layers 20 of the tab area 11 and the non-tab area 12 can also be made of different materials. In this way, there can be a certain boundary between the adhesive layers 20 of the tab area 11 and the non-tab area 12, so that the adhesive layer 20 of the tab area 11 can be torn off during the subsequent tearing of the film. Preferably, whether it is an adhesive layer 20 of the same material or an adhesive layer 20 of different materials, a gap greater than 0 is preferably formed between the adhesive layer 20 of the non-tab area 12 and the adhesive layer 20 of the tab area 11, so as to ensure the convenience and effect of subsequent tearing. Of course, there can also be no gap left. At this time, attention should be paid to the quality of the adhesive layer 20 of the non-tab area 12 during the subsequent tearing process.

[0077] In this embodiment, the orthographic projection of the electrode layer 40 of the conductive layer 30 is preferably located within the range of the conductive layer 30, so that the size of the electrode layer 40 is smaller than that of the conductive layer 30. More specifically, the electrode layer 40 is not provided on the outer side of the conductive layer 30 facing the tab area 11, so that the subsequent tab pressing will not affect the electrode layer 40. Further, in this embodiment, the orthographic projections of the electrode layer 40 and the base film layer 10 are basically overlapped.

[0078] In this embodiment, the orthographic projection of the adhesive layer 20 on the base film layer 10 is preferably located within the range of the base film layer 10. More specifically, the inner side of the conductive layer 30 facing the tab area 11 does not have the adhesive layer 20 after the film is torn off, so that the adhesive layer 20 does not affect the tab pressing. Optionally, the adhesive layer 20 may not be provided on the edge of the non-tab area 12 near the tab area 11, that is, the adhesive layer 20 does not completely cover the entire non-tab area 12 to reduce the impact on the tab pressing.

[0079] In general, the structure of the composite current collector of this embodiment after processing is as follows: the middle is a base film layer 10, the upper and lower sides of the base film layer 10 are conductive layers 30, the conductive layer 30 and the base film layer 10 are connected and compounded together by an adhesive layer 20, and the peripheral edge of the base film layer 10 is located on the inner wall of the conductive layer 30, so that there is a part of the space at the edge between the upper and lower conductive layers 30 that is not filled with the base film layer 10 and the adhesive layer 20, and this part of the space is the pole ear area 11, and the space where the base film layer 10 and the adhesive layer 20 covering its surface are located is the non-pole ear area 12, and the conductive layer 30 corresponding to the pole ear area 11 is pressed together by the pole ear pressing method. Electrode layers 40 are respectively arranged on the outer sides of the two conductive layers 30, and the positions of the electrode layer 40 and the base film layer 10 are aligned up and down, so that the electrode layer 40 avoids the position of the pole ear area 11.

[0080] It should be noted that the parameters in the embodiments of the present application can be adjusted as needed, and the order of the steps can also be adjusted according to the actual processing conditions, as long as the desired product can be obtained. The multiple in the above embodiments refers to at least two.

[0081] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0082] 1. Solve the problem of complex process of composite current collector production process in the prior art;

[0083] 2. The complexity of the composite current collector production process is greatly reduced, and the product reliability is higher;

[0084] 3. The conductive layer is thinned by etching, which makes the production and processing cost lower and more economical;

[0085] 4. Solve the high cost problem of additive manufacturing of composite current collectors in the existing technology and the problem of conductivity of the conductor layers on both sides of the polymer base film, and develop a mass production process based on the actual electrode production process, realizing low-cost, large-scale, high-quality processing and production.

[0086] Obviously, the above-described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0087] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0088] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A composite current collector production process, characterized in that: include: The base film layer and the conductive layer are composited, the base film layer (10) is composited with the conductive layer (30) via an adhesive layer (20) to form a composite film, and along the surface of the composite film, the composite film has a tab region (11) and a non-tab region (12), and the tab region (11) is located on the side of the non-tab region (12); Conductive layer corrosion, the conductive layer (30) is overall thinned by etching; The electrode layer is compounded, and the electrode layer (40) is compounded on the outer side of the conductive layer (30) away from the base film layer (10); Tearing off the film, tearing off the base film layer (10) and / or the adhesive layer (20) in the tab area (11); The tabs are pressed together to press the conductive layers (30) located on both sides of the tab area (11) onto a plane.

2. The composite current collector production process according to claim 1, characterized in that: The base film layer and the conductive layer are combined to include: The base film roll is unwound, and during the unwinding process, a pre-tear structure (13) is processed on the side of the base film layer (10), wherein the pre-tear structure (13) is located at the boundary between the pole lug area (11) and the non-pole lug area (12), or is offset from the boundary between the pole lug area (11) and the non-pole lug area (12) to the non-pole lug area (12) by a predetermined distance, and avoids the pressing position of the pole lug.

3. The composite current collector production process according to claim 1, characterized in that: The base film layer and the conductive layer are combined to include: Prepare the adhesive, mix the multi-component mixed hardening adhesive in a predetermined ratio through a screw pump to obtain the target adhesive solution, and weigh it before and after mixing to verify the mixing ratio to obtain a consistent adhesive solution.

4. The composite current collector production process according to claim 3, characterized in that: The base film layer and the conductive layer are combined and further include: Unwinding the base film roll, after the adhesive is prepared, unwinding the base film roll; The base film layer is coated with glue, and the mixed glue is transferred to the base film layer (10) through a concave roller to form the adhesive layer (20); Conductive layer unwinding, unwinding the conductive layer roll, during which the tension of the conductive layer roll in the conveying direction and in the transverse direction perpendicular to the conveying direction are kept the same; Compounding, compounding the conductive layer (30) on the base film layer (10) to form the composite film; Baking and curing, transporting the composite film after compounding into an oven for baking; The composite film is rolled up, and the baked composite film is rolled up and unloaded.

5. The composite current collector production process according to claim 4, characterized in that: The base film layer and the conductive layer are combined and further include: When the base film layer is coated with glue, the thickness of the mixed glue on the base film layer (10) is 0.2-1.0 micrometers; During the baking and curing, the oven temperature of the oven is 50-200 degrees Celsius and the conveying speed is 5-200 m / min.

6. The composite current collector production process according to claim 4, characterized in that: The base film layer and the conductive layer are combined and further include: For composite films with multi-component adhesive formula, secondary vacuum baking is performed after the baking and curing, and the composite film is transported to the oven again for secondary vacuum baking. The oven temperature is 50-200°C and the baking time is 1H-48H to ensure complete reaction of small molecules of the two-component adhesive.

7. The composite current collector production process according to claim 1, characterized in that: The base film layer and the conductive layer are combined and further include: The adhesive layer (20) comprises a tab adhesive portion and a non-tab adhesive portion, wherein the tab adhesive portion is located in the tab region (11), and the non-tab adhesive portion is located in the non-tab region (12), and a gap is provided between the tab adhesive portion and the non-tab adhesive portion.

8. The composite current collector production process according to claim 1, characterized in that: The conductive layer corrosion includes: Preparation of etching medium: mixing solid sodium hydroxide and pure water to obtain an etching solution of a predetermined ratio as the etching medium, or using corrosive gas as the etching medium; Unwinding the composite film, unwinding the composite film obtained by compounding the base film layer (10) and the conductive layer (30), and making the composite film flat after unwinding; The conductive layer is thinned by spraying the etching medium onto the surface of the conductive layer (30), and the conductive layer (30) having a target thickness is obtained after reaction; Cleaning the composite membrane, removing surface impurities from the composite membrane by pure water spraying or baking or clean gas cleaning, and then quickly baking to obtain a clean and tidy composite membrane; The composite film is rolled up, and the composite film is rolled up and the rolled composite film is flattened.

9. The composite current collector production process according to claim 8, characterized in that: The conductive layer corrosion also includes: When the conductive layer is thinned, the target thickness is 1-3.5 microns, and the error of the target thickness is within 1 micron.

10. The composite current collector production process according to claim 8, characterized in that: The conductive layer corrosion also includes etching medium recovery, and the etching medium recovery includes: When the etching medium is the etching solution, an excess amount of aluminum ingots or aluminum wires is added to the etching solution after the reaction, so that the sodium hydroxide solution is completely reacted, and the solution after the reaction is dried or evaporated to obtain sodium aluminate solid.

11. The composite current collector production process according to claim 1, characterized in that: The electrode layer composite comprises: Electrode layer preparation, pre-treating the electrode material of the electrode layer (40) according to the lithium battery production process requirements to meet the composite requirements; Unwinding the composite film, unwinding the composite film, and making the composite film flat after unwinding; The electrode piece is coated, baked or composited, and the electrode material is evenly distributed on the composite film by coating, and an electrode layer (40) is formed on the outside of the composite film; Roll pressing is carried out according to the production process requirements of lithium batteries.

12. The composite current collector production process according to claim 11, characterized in that: The film tearing comprises: Striping: after rolling, the electrode layer (40) is cut according to the size requirements of the electrode layer (40), and an elastic pad is laid under the cutting knife to ensure the striping effect of the unbonded area; After tearing, the composite film is pulled to the pre-tear structure (13) of the base film layer (10) after being stripped, and the base film layer (10) in the tab area (11) is torn off.

13. The composite current collector production process according to claim 12, characterized in that: The tab pressing comprises: When the tabs are pressed, at least one of cold pressing of the reinforcement ribs or ultrasonic roller welding is used for pressing.

14. A composite current collector, characterized in that: include: Basement membrane layer (10); A plurality of conductive layers (30), wherein the conductive layers (30) are composited on two opposite sides of the base film layer (10) via an adhesive layer (20), the orthographic projection of the base film layer (10) on the conductive layer (30) is located within the range of the conductive layer (30), a tab region (11) and a non-tab region (12) are provided between the conductive layers (30), the base film layer (10) is located within the non-tab region (12) and outside the tab region (11), and the conductive layers (30) on both sides of the tab region (11) are pressed together to form a tab; An electrode layer (40), the electrode layer (40) being composited on the outer side of the conductive layer (30) away from the base film layer (10).

15. The composite current collector according to claim 14, characterized in that: The orthographic projection of the electrode layer (40) on the conductive layer (30) is located within the range of the conductive layer (30).

16. The composite current collector according to claim 14, characterized in that: The orthographic projection of the adhesive layer (20) on the base film layer (10) is located within the range of the base film layer (10).

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