Dry film forming equipment

Abstract

The utility model provides dry film forming equipment which comprises a feeding mechanism and a film forming mechanism, when the feeding mechanism is used for feeding, a spreading roller which continuously rotates can pre-spread a dry mixture entering a feeding channel, so that the material is uniformly spread before film forming, and the phenomenon that some materials with poor fluidity are caked in the feeding process is avoided. Meanwhile, the spreading roller rotating continuously can control the feeding speed, the situation that the materials are compacted in the feeding process due to the fact that the feeding speed is too high is avoided, and the feeding uniformity and consistency of the materials are improved; through cooperation of the rotating film forming roller and the rotating spreading roller, preliminary film forming of dry materials to be subjected to film forming can be achieved, the equipment is suitable for materials with different properties, the feeding quality and the feeding speed of the materials can be ensured, the feeding uniformity and consistency are improved, and the size consistency of pole pieces obtained through subsequent preparation is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dry electrode process equipment, in particular to a dry film forming equipment. BACKGROUND

[0002] The traditional electrode manufacturing process is a wet coating process, which requires the use of solvents and subsequent recovery of solvents, resulting in a large set of electrode production equipment and high cost. In recent years, dry electrode process has been valued and developed, which does not require solvent to assist electrode processing, eliminates the corresponding drying and solvent recovery process and device, and can greatly reduce the investment cost of lithium battery project, electrode manufacturing cost and unit carbon emission of product. CONTENT OF THE INVENTION

[0003] Therefore, the purpose of the present application is to provide a dry film forming equipment.

[0004] In order to achieve the above purpose, the present application provides a dry film forming equipment, which comprises:

[0005] A feeding mechanism comprising a feeding part and a spreading roller, a feeding channel is formed between the feeding part and the spreading roller, the feeding channel comprises a feeding port, a first gap and a discharging port arranged in sequence, and the feeding channel is configured to allow the dry material to be formed into a film to enter from the feeding port and flow out from the discharging port along the first gap;

[0006] A film forming mechanism comprising a film forming roller and a calender unit, the film forming roller is located below the discharging port and forms a first roller gap with the spreading roller, the film forming roller is configured to receive the dry material to be formed into a film flowing out from the discharging port and drive the dry material to be formed into a film to pass through the first roller gap to form an initial film piece, and the calender unit is configured to calender the initial film piece into a finished film piece.

[0007] Optionally, the calender unit comprises at least two calender rollers and a composite roller arranged in sequence, and a second roller gap is formed between the calender roller and the adjacent film forming roller, between two adjacent calender rollers and between the calender roller and the composite roller, and the second roller gap is for the initial film piece to pass through.

[0008] Optionally, the outer diameter of the film forming roller and the outer diameter of the composite roller are both larger than the outer diameter of the calender roller.

[0009] Optionally, the outer diameters of at least two adjacent calender rollers are the same.

[0010] Optionally, along the direction from the film forming roller to the composite roller, the plurality of calender rollers comprise a plurality of first calender rollers and a plurality of second calender rollers arranged alternately in sequence, and the outer diameter of the second calender roller is larger than the outer diameters of the two adjacent first calender rollers.

[0011] Optionally, the composite roller is away from the film forming roller side is a film outlet side, the dry film forming equipment further comprises a winding and unwinding mechanism, the winding and unwinding mechanism comprises a winding roller and an unwinding roller, the unwinding roller is wound with a current collector roll, the winding and unwinding mechanism is configured to unwind the current collector roll through the unwinding roller to release the current collector, and the current collector extends along the direction from the unwinding roller to the winding roller until it is wound by the winding roller, a second gap is formed between the current collector and the film outlet side, and the finished film passes through the second gap and is bonded to the current collector in the second gap.

[0012] Optionally, the film forming mechanism and the feeding mechanism are both provided with two, the two film forming mechanisms are mirror symmetrically distributed with the extension direction of the current collector as the center, and the film outlet side of the composite roller of the two film forming mechanisms is away from the current collector and forms the second gap.

[0013] Optionally, the film forming mechanism and the feeding mechanism are both provided with one, the dry film forming equipment further comprises a pressing roller, the pressing roller is located away from the film forming roller side of the composite roller, a third gap is formed between the pressing roller and the composite roller, and the third gap is used for the current collector and the finished film to pass through at the same time.

[0014] Optionally, the feeding part comprises two first baffles arranged oppositely, a second baffle located between the two first baffles and connected with the two first baffles, and the spreading roller is located between the two first baffles, and the feeding channel is formed between the spreading roller and the second baffle.

[0015] Optionally, the second baffle is arranged obliquely, and the distance between the second baffle and the feeding port is greater than the distance between the second baffle and the discharging port.

[0016] Optionally, the second baffle is arranged obliquely along a first direction, the included angle between the first direction and the horizontal plane is 40°-80°, and / or the vertical distance between the second baffle and the center point of the spreading roller is 100-600 mm.

[0017] Optionally, the feeding part and the spreading roller are both provided with a cooling interlayer inside, and the cooling interlayer is used for passing cooling medium; and / or

[0018] The inside of the film forming roller, the calender roller and the composite roller is provided with a heating assembly, and the heating assembly is used for heating the film forming roller, the calender roller and the composite roller.

[0019] Optionally, the size of the second nip is 0.01-1 mm, and / or the outer diameter size of the film forming roller is 200-1200 mm, and / or the outer diameter size of the calender roller is 80-600 mm, and / or the outer diameter size of the composite roller is 200-1200 mm, and / or the outer diameter size of the spreading roller is 80-300 mm, and / or the size of the first nip is 1-10 mm.

[0020] As can be seen from the above, the dry film forming device provided by the application comprises a feeding mechanism and a film forming mechanism. When feeding through the feeding mechanism, the continuously rotating spreading roller can pre-spread the dry mixture entering the feeding channel, so that the material is uniformly spread before film forming, avoiding the caking of some materials with poor fluidity during feeding. At the same time, the continuously rotating spreading roller can control the feeding speed, avoiding the compaction of the material during feeding caused by too large feeding speed, and improving the uniformity and consistency of the material feeding. The film forming roller can receive the dry material to be formed flowing out of the discharge port and drive the dry material to be formed into the feeding channel formed by the film forming roller and the spreading roller. Through the cooperation of the rotating film forming roller and the rotating spreading roller, the dry material to be formed can be preliminarily formed. The dry film forming device of the application is suitable for materials with different properties, and can ensure the quality and speed of material feeding, so as to improve the uniformity and consistency of the material feeding and the size consistency of the pole piece prepared subsequently. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the application or related art, the drawings needed in the embodiments or related art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0022] Figure 1 A process flow block diagram of a dry electrode process is shown;

[0023] Figure 2 A first schematic diagram of the dry film forming device of the embodiment of the application is shown;

[0024] Figure 3 A schematic diagram of the dry film forming process of the first dry film forming device of the embodiment of the application is shown;

[0025] Figure 4 A schematic diagram of the dry film forming process of the second dry film forming device of the embodiment of the application is shown;

[0026] Figure 5 A third schematic diagram of the dry film forming device of the embodiment of the application is shown;

[0027] Figure 6 FIG. 3 shows a schematic diagram of a third dry film forming device according to an embodiment of the present application;

[0028] Figure 7 FIG. 4 shows a fourth dry film forming device according to an embodiment of the present application;

[0029] Figure 8 FIG. 5 shows a cross-sectional view of the fourth dry film forming device according to an embodiment of the present application in the B-B direction;

[0030] Figure 9 FIG. 6 shows a cross-sectional view of the fourth dry film forming device according to an embodiment of the present application in the A-A direction.

[0031] In the figure: 1, feeding mechanism; 11, feeding part; 111, first baffle; 112, second baffle; 12, spreading roller; 13, feeding channel; 131, feeding port; 132, discharging port; 133, first gap; 14, height sensor; 2, film forming mechanism; 21, film forming roller; 22, calender unit; 221, calender roller; 221a, first calender roller; 221b, second calender roller; 222, compound roller; 2221, film discharging side; 3, first roller gap; 4, second roller gap; 5, unwinding and winding mechanism; 51, unwinding roller; 52, winding roller; 53, current collector; 6, compression roller; 7, second gap; 8, dry material to be formed into a film; 8a, initial film piece; 8b, finished film piece; 9, third gap. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions and advantages of the present application clearer, the present application is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0033] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be understood as their common meanings to those skilled in the art to which the present application pertains. The terms "first", "second" and similar terms used in the embodiments of the present application do not represent any order, number or importance, but are only used to distinguish different components. The terms "comprise", "include" and similar terms mean that the components or objects before the terms encompass the components or objects listed after the terms and their equivalents, without excluding other components or objects. The terms "connect" or "connected" and similar terms do not mean only physical or mechanical connections, but can also include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right" and the like only represent relative positional relationships, which can change when the absolute positions of the described objects change.

[0034] A key component of the storage potential of an energy storage device is the electrode. The electrochemical capability of an electrode (e.g., capacity and efficiency of a battery electrode) is influenced by a variety of factors. For example, the ratio of active material, binder, and conductive agent in the electrode; the physical properties of the materials (e.g., particle size and surface area of the active material, surface characteristics of the active material); and the physical characteristics of the electrode film (e.g., density, porosity, cohesiveness, and adhesion to the current collector), among others.

[0035] A dry electrode process uses a high shear and / or high pressure processing step to disintegrate and mix the electrode film materials. In comparison to electrode films produced using a wet process, the dry electrode process does not require the use of solvents, and thus does not require post-processing and recovery of solvents, which can greatly simplify the manufacturing process and reduce the structure of the manufacturing equipment.

[0036] The mainstream of dry electrode preparation is the binder fiberization method, which is to add active material, conductive agent powder into solid binder, and then apply high shear force to make the binder fiberized to bond the powder, and then the binder is compacted and thinned by extrusion to form a self-supporting film, and the self-supporting film is rolled and compounded with the current collector to form an electrode. Currently, the binder is usually dropped from above into the nip of two pressure rollers arranged opposite to each other, and the electrode film is extruded by the rotation of the two pressure rollers, and then thinned and corrected by multi-stage calendering to become a finished film.

[0037] Figure 1 A process flow diagram of a dry electrode process is shown. As used herein, the term "dry" means that no liquid phase solvents and additives are used in the mixing and coating process of the electrode during the process steps herein (except during the final impregnation of electrolyte step).

[0038] Referring to Figure 1 As shown, prior to preparation, dry active material, dry conductive agent, and dry binder are mixed to form a dry mix, which is subjected to preliminary fiberization using, for example, a jet mill (not shown). The preliminarily fiberized dry mix is then dropped from above into the nip of two pressure rollers arranged opposite to each other, and the electrode film is extruded by the rotation of the two pressure rollers, and then thinned and corrected by multi-stage calendering to become a finished film. The finished film can be an embedded / intermixed dry film or a self-supporting electrode film (or electrochemically active self-supporting film). Finally, the finished film is attached to a current collector (e.g., a metal foil), which forms an electrode.

[0039] The self-supporting dry electrode film manufactured above can provide improved properties relative to typical electrode films manufactured using a wet process. For example, the dry electrode film can provide improved film strength, improved cohesion, improved adhesion, improved electrical performance, or reduced defect occurrence, where defects can include holes, cracks, surface pits in the electrode film. The adhesion can be adhesion to the current collector. The electrical performance can be specific capacity. The film strength can be tensile strength, etc.

[0040] Currently, the process equipment maturity of the dry electrode process is directly related to the processing difficulty of the material and formula. Graphite negative electrode particles are large and have good flowability between particles, and thus are the easiest to process. The current mass production equipment can achieve a processing speed of more than 60 m / min; the positive electrode ternary material particles are also large and have good sphericity, and the forming speed is about 30 m / min. Lithium iron phosphate (LFP), especially nano-level LFP material, has fine particles and irregular shape, resulting in easy compaction and poor particle flowability, and thus there is no good forming equipment, and the process equipment maturity is low.

[0041] In addition, the electrode manufacturing process has strict requirements on the electrode size tolerance, while the dry electrode process directly falls the primary fibrous dry mixture from above into the nip between the two compression rollers arranged oppositely to form a film, resulting in very uneven amount of powder entering the nip between the two compression rollers, and the film forming effect and spreading effect of the film sheet during the subsequent calendering process are also uneven, ultimately resulting in the electrode size tolerance prepared is usually large, which is not conducive to the subsequent electrode assembly process.

[0042] Therefore, there is an urgent need to provide a new dry film forming equipment suitable for various different materials and capable of improving the consistency of the electrode sheet size.

[0043] Based on this, the application provides a dry film forming equipment.

[0044] Figure 2 A first schematic diagram of the dry film forming equipment of the embodiment of the application is shown. Figure 3 A schematic diagram of the first dry film forming equipment of the embodiment of the application during dry film forming is shown.

[0045] Referring to Figure 2 and Figure 3 The dry film forming equipment includes:

[0046] The feeding mechanism 1 includes a feeding part 11 and a spreading roller 12, and a feeding channel 13 is formed between the feeding part 11 and the spreading roller 12. The feeding channel 13 includes a feeding port 131, a first gap 133 and a discharge port 132 arranged in sequence. The feeding channel 13 is configured to allow the dry material 8 to be formed into a film to enter from the feeding port 131 and flow out from the discharge port 132 along the first gap 133.

[0047] The film forming mechanism 2 comprises a film forming roller 21 and a calender unit 22. The film forming roller 21 is located below the discharge port 132 and forms a first roller gap 3 with the spreading roller 12. The film forming roller 21 is configured to receive the dry material 8 to be formed into a film from the discharge port 132 and drive the dry material 8 to be formed into a film through the first roller gap 3 to form an initial film piece 8a. The calender unit 22 is configured to calender the initial film piece 8a into a finished film piece 8b.

[0048] Specifically, the feeding mechanism 1 comprises a feeding part 11 and a spreading roller 12. The feeding part 11 and the spreading roller 12 form a feeding channel 13 therebetween. The feeding channel 13 comprises a feeding port 131, a first gap 133 and a discharge port 132 arranged in sequence. The first gap 133 can be a middle part of the feeding channel 13. The feeding port 131 is located above the first gap 133, and the discharge port 132 is located below the first gap 133.

[0049] In actual dry film forming preparation process, the dry material 8 to be formed into a film is fed from the feeding port 131 and flows along the first gap 133 until it flows out of the discharge port 132. The dry material 8 to be formed into a film is a preliminary fibrousized dry mixture, which is a mixture of dry active material, dry conductive agent and dry adhesive.

[0050] When feeding through the feeding mechanism 1, the continuously rotating spreading roller 12 can pre-spread the dry mixture entering the feeding channel 13, so that the material is uniformly spread before film forming, avoiding the caking of some materials with poor fluidity during feeding. At the same time, the continuously rotating spreading roller 12 can control the feeding speed to avoid the material being compacted during feeding due to excessive feeding speed, thereby improving the feeding uniformity and consistency of the material.

[0051] In specific implementation, the spreading roller 12 can be controlled to rotate forward (i.e. clockwise) or reverse (i.e. counterclockwise) under the driving of the corresponding driving motor. For different materials, the spreading roller 12 can be controlled to rotate in different directions. For example, when the material to be fed is a material with poor fluidity and easy to be compacted, the spreading roller 12 is controlled to rotate forward. At this time, the forward rotating spreading roller 12 can spread and loosen the material to avoid caking or compaction of the material during feeding. When the material to be fed is a material with good fluidity, the spreading roller 12 is controlled to rotate reverse. At this time, the reverse rotating spreading roller 12 can extrude the material to pre-extrude the air in the material, which is more conducive to the subsequent film forming of the material.

[0052] The film forming mechanism 2 comprises a film forming roller 21 and a calender unit 22. The film forming roller 21 is located below the discharge port 132 and forms a first roller gap 3 with the spreading roller 12. When the dry material 8 to be formed is fed from the feeding port 131, flows along the first gap 133 until it flows out of the discharge port 132, and then flows to the film forming roller 21 located below it. The rotating film forming roller 21 drives the dry material 8 to be formed to pass through the first roller gap 3. At this time, under the joint action of the film forming roller 21 and the spreading roller 12, the dry material 8 to be formed is formed into an initial film 8a. It is worth noting that the initial film 8a is only spread on the film forming roller 21 and has not been calendered, so it is only a simple spread film formed by the film forming roller 21. Then the initial film 8a enters the calender unit 22, which calenders it to form the finished film 8b.

[0053] The film forming roller 21 can receive the dry material 8 to be formed flowing out of the discharge port 132 and drive it into the feeding channel 13 formed by the film forming roller 21 and the spreading roller 12. Through the cooperation of the rotating film forming roller 21 and the rotating spreading roller 12, the dry material 8 to be formed can be preliminarily formed.

[0054] In this application, the feeding mechanism 1 can control the spreading roller 12 to perform different rotating operations for different properties of the material to spread and loosen the material, avoid the material from caking or being compacted during feeding, and also can pre-press the air in the material, which is more conducive to the subsequent film forming of the material. At the same time, through the cooperation of the rotating film forming roller 21 and the rotating spreading roller 12, the dry material 8 to be formed can be preliminarily formed to form an initial film 8a, and finally the initial film 8a is calendered by the calender unit 22 to form a finished film 8b.

[0055] The dry film forming equipment of the present application is suitable for different properties of the material, which can ensure the quality and speed of the material feeding, improve the uniformity and consistency of the feeding, and improve the consistency of the size of the pole piece prepared subsequently.

[0056] In some embodiments, continuing to refer to Figure 2 and Figure 3 The calender unit 22 comprises at least two calender rollers 221 and a composite roller 222 arranged in sequence. The second roller gap 4 is formed between the calender roller 221 and the adjacent film forming roller 21, between the adjacent two calender rollers 221, and between the calender roller 221 and the composite roller 222, and the initial film 8a passes through the second roller gap 4.

[0057] Specifically, the calendering roller 221 can be provided with two or multiple, the calendering roller 221 is used for further film forming correction and flattening of the initial film sheet 8a, the initial film sheet 8a out of the first roller gap 3 passes through multiple second roller gaps 4 in turn, and the initial film sheet 8a is continuously calendered, corrected and flattened under the action of multiple calendering rollers 221 and the composite roller 222, and finally forms the finished film sheet 8b, which is out of the side of the composite roller 222 away from the film forming roller 21.

[0058] In some embodiments, continuing to refer to Figure 2 and Figure 3 The size of the film forming roller 21 and the size of the composite roller 222 are both larger than the size of the calendering roller 221.

[0059] Specifically, the film forming roller 21 is large in size, which can provide large rigidity on the one hand, facilitating cooperation with the feeding mechanism 1 and supporting the subsequent calendering unit 22; on the other hand, the large size of the film forming roller 21 can increase the preheating time of the material on the film forming roller 21 to soften and be more easily processed, facilitating the subsequent calendering film forming to form the finished film sheet 8b.

[0060] The calendering roller 221 is small in size, which can provide better film forming effect, so that the calendering roller 221 can more easily stretch and form the film of the initial film sheet 8a, which is beneficial to the film forming of the initial film sheet 8a and can improve the film forming quality. At the same time, the calendering roller 221 is small in size, and when the corresponding driving motor drives the calendering roller 221 to rotate, the stability of the calendering roller 221 is smaller, which is more conducive to improving the film forming quality.

[0061] The composite roller 222 is large in size, which can provide better flattening effect, so that the final prepared finished film sheet 8b has better spreading effect, ensuring that the final prepared finished film sheet 8b has good quality.

[0062] In this way, in the advancing direction of the initial film sheet 8a, the first film forming roller 21 is large in size, which is convenient for spreading the material; the calendering roller 221 in the middle is small in size, which is convenient for calendering the initial film sheet 8a to make it better film forming; and the composite roller 222 at the last is large in size, which is convenient for spreading the finished film sheet 8b.

[0063] In this application, by controlling the rollers at different positions in the film forming mechanism 2 to have different sizes, the material can be better preliminarily spread, film formed and spread, thereby the uniformity and consistency of the final prepared finished film sheet 8b can be improved, and the film forming quality can be improved.

[0064] For the plurality of calender rollers 221 located in the middle, different sizes of the calender rollers 221 also have different effects on the film forming effect. Therefore, in this application, the sizes of the calender rollers are different for materials with different properties.

[0065] In some embodiments, continuing to refer to Figure 3 , the outer diameters of at least two adjacent calender rollers 221 are the same.

[0066] Specifically, among the plurality of calender rollers 221, the outer diameters of only two adjacent calender rollers 221 can be the same, or the outer diameters of all the plurality of calender rollers 221 can be the same.

[0067] For some materials such as graphite negative electrode materials, due to good flowability between particles, film forming and spreading are easy. For such materials, film forming and spreading are relatively easy, and there is no strict requirement for the outer diameter of the calender roller 221. Therefore, the application sets the outer diameters of the plurality of calender rollers 221 to be the same, which facilitates effective film forming and good spreading of the material, and the same outer diameters of the plurality of calender rollers 221 facilitate assembly and actual control of the dry film forming equipment, improving the use flexibility of the equipment.

[0068] Figure 4 A schematic diagram of a second dry film forming equipment according to an embodiment of the application is shown.

[0069] In some embodiments, referring to Figure 4 , along the direction from the film forming roller 21 to the composite roller 222 (i.e. the direction shown by P in Figure 4 , the plurality of calender rollers 221 include a plurality of first calender rollers 221a and a plurality of second calender rollers 221b arranged alternately in sequence, and the outer diameter of the second calender roller 221b is larger than the outer diameters of the two adjacent first calender rollers 221a.

[0070] Specifically, taking the plurality of calender rollers 221 including six calender rollers 221 as an example, along the direction from the film forming roller 21 to the composite roller 222, the outer diameter of the first calender roller 221 is small, the outer diameter of the second calender roller 221 is large, the outer diameter of the third calender roller 221 is small, the outer diameter of the fourth calender roller 221 is large, the outer diameter of the fifth calender roller 221 is small, and the outer diameter of the sixth calender roller 221 is large. In this way, the outer diameters of the plurality of calender rollers 221 are alternately arranged in the order of small-large-small-large-small-large-...

[0071] For the calender roller 221 with a small outer diameter, the outer diameter is small, the film forming effect is better, and the initial film sheet 8a is convenient for film forming; for the calender roller 221 with a large outer diameter, the outer diameter is large, the spreading effect is better, and the initial film sheet 8a is convenient for spreading. Therefore, the plurality of calender rollers 221 are alternately arranged in the order of small-large-small-large-small-large…, which can repeatedly perform film forming-spreading-film forming-spreading-film forming-spreading… on the initial film sheet 8a, so that the film forming effect of the initial film sheet 8a can be improved, and the spreading effect can be improved, so that the final product film sheet 8b has good film forming effect and spreading effect.

[0072] For materials such as lithium iron phosphate with fine particles, irregular shape, easy compaction and poor particle flow, the same outer diameter of the calender roller 221 is not conducive to film forming, therefore, in the present application, for such materials, the outer diameters of the plurality of calender rollers 221 are alternately arranged in the order of small-large-small-large-small-large…, so that the plurality of calender rollers 221 can repeatedly perform film forming-spreading-film forming-spreading-film forming-spreading… on the initial film sheet 8a, thereby improving the film forming effect of the initial film sheet 8a and improving the spreading effect, so that the final product film sheet 8b has good film forming quality.

[0073] In some embodiments, the composite roller 222 is away from one side of the film forming roller 21 as an outflow side 2221, and the dry film forming device further comprises a winding and unwinding mechanism 5, the winding and unwinding mechanism 5 comprising a winding roller 52 and an unwinding roller 51, the unwinding roller 51 being wound with a current collector roll, the winding and unwinding mechanism 5 being configured to unwind the current collector roll through the unwinding roller 51 to release the current collector 53, and the current collector 53 extending along the direction from the unwinding roller 51 to the winding roller 52 until being wound by the winding roller 52, a second gap 7 being formed between the current collector 53 and the outflow side 2221, the product film sheet 8b passing through the second gap 7 and being bonded with the current collector 53 in the second gap 7.

[0074] In specific implementation, the current collector roll is unwound through the unwinding roller 51 to release the current collector 53, the released current collector 53 extends along the direction from the unwinding roller 51 to the winding roller 52 and enters the second gap 7, at the same time, the product film sheet 8b outflows from the outflow side 2221 of the composite roller 222 also passes through the second gap 7, at this time, the product film sheet 8b and the current collector 53 contact and bond in the second gap 7, the bonded product film sheet 8b and the current collector 53 continue to outflow from the second gap 7 under the action of the winding roller 52 and are wound by the winding roller 52, and finally the wound product is the single-side film formed electrode sheet (the electrode sheet formed by bonding the product film sheet 8b on one side of the current collector 53) prepared finally.

[0075] Figure 5 A third schematic view of the dry film forming device of the embodiment of the present application is shown,Figure 6 FIG. 3 shows a schematic diagram of a third dry film forming device according to an embodiment of the present application when performing a film forming process.

[0076] In some embodiments, referring to FIGS. 1, 2 and 3, the film forming mechanism 2 and the feeding mechanism 1 are provided in pairs, the two film forming mechanisms 2 are symmetrically distributed with respect to the extension direction of the current collector 53, and the second gap 7 is formed between the film outlet side 2221 of the composite roller 222 of each film forming mechanism 2 and the current collector 53. Figure 5 Figure 6 In some embodiments, referring to FIGS. 1, 2 and 3, the film forming mechanism 2 and the feeding mechanism 1 are provided in pairs, the two film forming mechanisms 2 are symmetrically distributed with respect to the extension direction of the current collector 53, and the second gap 7 is formed between the film outlet side 2221 of the composite roller 222 of each film forming mechanism 2 and the current collector 53.

[0077] In specific implementation, the current collector roll is loosened by the unwinding roller 51 to release the current collector 53, and the released current collector 53 extends along the direction from the unwinding roller 51 to the winding roller 52 and enters the gap between the film outlet sides 2221 of the two composite rollers 222. At the same time, the two finished film pieces 8b that pass through the film outlet sides 2221 of the two composite rollers 222 also pass through the corresponding second gaps 7. At this time, in the two second gaps 7, the two finished film pieces 8b are in contact with and bonded to one side of the current collector 53, respectively. After the two finished film pieces 8b are bonded to the two sides of the current collector 53, the two finished film pieces 8b continue to pass through the second gaps 7 under the action of the winding roller 52 and are wound by the winding roller 52. The final product is the electrode tab with double-sided film (the electrode tab formed by the current collector 53 with the finished film pieces 8b bonded to the opposite sides of the current collector 53).

[0078] In the present application, based on different actual needs, the electrode tab with single-sided film or the electrode tab with double-sided film can be prepared by the dry film forming device according to the present application, and the uniformity and consistency of the electrode tab are good.

[0079] In some embodiments, referring to FIGS. 1, 2 and 3, the film forming mechanism 2 and the feeding mechanism 1 are provided in pairs, the two film forming mechanisms 2 are symmetrically distributed with respect to the extension direction of the current collector 53, and the second gap 7 is formed between the film outlet side 2221 of the composite roller 222 of each film forming mechanism 2 and the current collector 53. Figure 2 Figure 3 Figure 4 In some embodiments, referring to FIGS. 1, 2 and 3, the film forming mechanism 2 and the feeding mechanism 1 are provided in pairs, the two film forming mechanisms 2 are symmetrically distributed with respect to the extension direction of the current collector 53, and the second gap 7 is formed between the film outlet side 2221 of the composite roller 222 of each film forming mechanism 2 and the current collector 53.

[0080] ​​​Specifically, in order to make the adhesion effect of the current collector 53 and the finished film sheet 8b better when the film is formed on one side, the present application also provides the pressing roller 6. The pressing roller 6 is located on the side of the composite roller 222 away from the film forming roller 21, and a third gap 9 is formed between the pressing roller 6 and the composite roller 222, which is used for the current collector 53 and the finished film sheet 8b to pass through at the same time. When the current collector 53 and the finished film sheet 8b pass through at the same time, the pressing of the pressing roller 6 and the composite roller 222 at the same time can ensure the effective adhesion of the current collector 53 and the finished film sheet 8b, improve the adhesion effect of the two, and ensure that the stability of the electrode sheet prepared finally is good and the finished film sheet 8b will not fall off.

[0081] Figure 7 Fig. 4 shows a fourth schematic view of the dry film forming device of the present application, Figure 8 Fig. 5 shows a cross-sectional view of the fourth dry film forming device of the present application in the B-B direction, Figure 9 Fig. 6 shows a cross-sectional view of the fourth dry film forming device of the present application in the A-A direction.

[0082] In some embodiments, referring to Figs. 1-6, Figure 7 、 Figure 8 and Figure 9 , the feeding part 11 includes two oppositely arranged first baffles 111, a second baffle 112 located between the two first baffles 111 and connected to both of the first baffles 111, and the spreading roller 12 is partially located between the two first baffles 111 and a feeding channel 13 is formed between the spreading roller 12 and the second baffle 112.

[0083] Specifically, the two oppositely arranged first baffles 111 and the second baffle 112 connected to both of the first baffles 111 form a structure similar to a "U" shape. Such structure is beneficial for the flow of the material and can block the material from flowing outwards, thereby avoiding waste of the material.

[0084] Further, the bottom of the first baffle 111 directly contacts the film forming roller 21, so as to avoid the material from flowing out of the gap between the first baffle 111 and the film forming roller 21. At the same time, since the first baffle 111 is arranged along the radial direction of the film forming roller 21, the contact area between the first baffle 111 and the film forming roller 21 is small, and the contact between the first baffle 111 and the film forming roller 21 will not have a significant impact on the rotation of the film forming roller 21.

[0085] Since the second baffle 112 is arranged along the axial direction of the film forming roller 21, the contact area between the second baffle 112 and the film forming roller 21 is large, and thus the contact between the second baffle 112 and the film forming roller 21 will have a significant impact on the rotation of the film forming roller 21.

[0086] Therefore, in this application, the bottom of the second baffle 112 and the film-forming roller 21 do not need to be in direct contact; a very small gap can be formed between them. This avoids the second baffle 112 affecting the rotation of the film-forming roller 21, thereby preventing any impact on the film-forming effect. Simultaneously, since the material moves away from the second baffle 112 under the influence of the film-forming roller 21, the material will not flow out through the gap between the second baffle 112 and the film-forming roller 21, thus preventing material waste.

[0087] In some embodiments, the second baffle 112 is inclined and the distance between the second baffle 112 and the feed inlet 131 is greater than the distance between the second baffle 112 and the discharge outlet 132. Thus, the entire feed channel 13 is formed into a conical structure that is larger at the top and smaller at the bottom, which can reduce the friction between the first baffle 111 and the second baffle 112 and the material, and facilitate the feeding of the material.

[0088] In some embodiments, the second baffle 112 is inclined along a first direction, the angle between the first direction and the horizontal plane is 40 to 80°, and / or the vertical distance between the second baffle 112 and the center point of the spreading roller 12 is 100 to 600 mm.

[0089] Specifically, the angle between the first direction and the horizontal plane is 40° to 80°, which is a suitable angle to facilitate material feeding. When the material has poor flowability, the angle between the first direction and the horizontal plane is controlled to be larger to increase the inclination of the second baffle 112, reduce the friction between the material and the baffle, and ensure the material feed rate. When the material has good flowability, the angle between the first direction and the horizontal plane is controlled to be smaller to reduce the inclination of the second baffle 112, which facilitates the control of the feed rate.

[0090] For example, the angle between the first direction and the horizontal plane can be 40°, 50°, 60°, 70°, 80°, etc.

[0091] The vertical distance between the center point of the second baffle 112 and the center point of the spreading roller 12 (i.e.) Figure 7 The L in the figure is 100-600mm. In this way, the size of the first gap 133 in the feed channel 13 can be controlled, thereby controlling the amount of material stored, avoiding excessive accumulation of material in the feed channel 13, which would cause the material to be compacted or agglomerated, and also avoiding the material being too small to meet the film forming requirements of the film forming roller 21.

[0092] For example, the vertical distance between the second baffle 112 and the center point of the spreading roller 12 (i.e., Figure 7 The L in the figure can be 100mm, 200mm, 300mm, 400mm, 500mm, 600mm, etc.

[0093] In some embodiments, the feeding part 11 and the spreading roller 12 are internally provided with cooling layers for passing cooling medium; and / or the film forming roller 21, the calender roller 221 and the composite roller 222 are internally provided with heating assemblies for heating the film forming roller 21, the calender roller 221 and the composite roller 222.

[0094] Specifically, the material to be formed has good fluidity at low temperature, and when the temperature rises, the viscosity of the material to be formed increases, so that the fluidity of the material decreases.

[0095] Therefore, in the present application, the feeding part 11 and the spreading roller 12 are internally provided with cooling layers for passing cooling medium, so that the temperature of the feeding part 11 and the spreading roller 12 is low, thereby ensuring that the material always maintains low temperature during storage and feeding, ensuring that the viscosity of the material is low and the fluidity is good, avoiding the caking of the material due to high viscosity.

[0096] For example, the cooling medium passed in can be cold water. The temperature of the cold water is preferably lower than 20℃.

[0097] The film forming roller 21, the calender roller 221 and the composite roller 222 are internally provided with heating assemblies. For example, the heating assemblies can be heating layers or resistance wires, etc.

[0098] The heating layers are used for passing heating medium to heat the film forming roller 21, the calender roller 221 and the composite roller 222. The resistance wires are used for electrically heating the film forming roller 21, the calender roller 221 and the composite roller 222, so that when the material contacts the film forming roller 21 and the subsequent calender roller 221 and composite roller 222, the temperature of the material rises, the viscosity increases, and the fluidity becomes poor, so that the material with increased viscosity can be better pressed, formed and spread under the action of the film forming mechanism 2.

[0099] For example, the heating medium passed in can be hot water or hot oil. The temperature of the heating medium can be 60-200℃.

[0100] In some embodiments, the size of the second roller gap 4 is 0.01-1mm, and / or the outer diameter of the film forming roller 21 is 200-1200mm, and / or the outer diameter of the calender roller 221 is 80-600mm, and / or the outer diameter of the composite roller 222 is 200-1200mm, and / or the outer diameter of the spreading roller 12 is 80-300mm, and / or the size of the first roller gap 3 is 1-10mm.

[0101] Specifically, the size of the second roll gap 4 is 0.01-1mm, so that the second roll gap 7 can meet the thickness requirement of the initial film 8a and ensure that the initial film 8a can be squeezed by the two adjacent rollers, thereby improving the calendering effect. For example, the size of the second roll gap 4 can be 0.01mm, 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, etc.

[0102] The size of the first roll gap 3 is 1-10mm, so that the feeding channel 13 can meet the requirements of material storage and feeding, and ensure that the amount of material storage and the amount of film forming required by the subsequent film forming roller 21 match. For example, the size of the first roll gap 3 can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, etc.

[0103] Further, the outer walls of the film forming roller 21, the calendering roller 221, the composite roller 222 and the compression roller 6 are sprayed with tungsten carbide for surface treatment, and the roughness is 0.02. Hydraulic pressure is applied to both sides of the film forming roller 21 and the compression roller 6 to maintain a certain linear pressure between the rollers, and the maximum linear pressure is 250kg / cm, so as to ensure the film forming effect.

[0104] Further, the film forming roller 21, the calendering roller 221 and the composite roller 222 are driven by separate drive motors, and the rotation speed of the film forming roller 21, the calendering roller 221 and the composite roller 222 gradually increases, so as to improve the film forming effect.

[0105] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the acts or steps recited in the claims can be performed in an order different than that described above and still achieve desirable results. Additionally, the process depicted in the figures does not necessarily require the particular order shown, or sequential order, to achieve desirable results. In some implementations, multitasking and parallel processing can be advantageous.

[0106] Those skilled in the art will understand that the above discussion of any of the embodiments is merely exemplary and is not intended to be limiting of the scope of the present application; the above embodiments or technical features among different embodiments can also be combined under the idea of the present application, the steps can be implemented in any order, and there are many other changes of different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of brevity.

[0107] Embodiments of the present application are intended to embrace all such alterations, modifications, and variations that fall within the scope of the present application. Accordingly, although the present application has been described with respect to example embodiments, it will be apparent that the scope of the application is not limited to these described embodiments, but instead encompasses any and all alterations, modifications and variations that can fall within the scope of the present application.

Claims

1. A dry film forming apparatus characterized by comprising: The application relates to a dry film forming device. The feeding mechanism comprises a feeding part and a spreading roller, a feeding channel is formed between the feeding part and the spreading roller, the feeding channel comprises a feeding port, a first gap and a discharging port arranged in sequence, the feeding channel is configured to allow the dry material to be formed into a film to enter from the feeding port and flow out from the discharging port along the first gap. The film forming mechanism comprises a film forming roller and a calender unit, the film forming roller is located below the discharging port and forms a first roller gap with the spreading roller, the film forming roller is configured to receive the dry material to be formed into a film flowing out from the discharging port and drive the dry material to pass through the first roller gap to form an initial film piece, and the calender unit is configured to calender the initial film piece into a finished film piece.

2. The dry film forming apparatus according to claim 1, wherein The calender unit comprises at least two calender rollers and a composite roller arranged in sequence, second roller gaps are formed between the calender roller and the adjacent film forming roller, between two adjacent calender rollers and between the calender roller and the composite roller, and the second roller gaps are used for the initial film piece to pass through.

3. The dry film forming apparatus according to claim 2, wherein The outer diameter of the film forming roller and the outer diameter of the composite roller are both larger than the outer diameter of the calender roller.

4. The dry film forming apparatus according to claim 3, wherein The outer diameters of at least two adjacent calender rollers are the same.

5. The dry film forming apparatus according to claim 3, wherein In the direction from the film forming roller to the composite roller, the plurality of calender rollers comprise a plurality of first calender rollers and a plurality of second calender rollers arranged in sequence alternately, and the outer diameter of the second calender roller is larger than the outer diameters of two adjacent first calender rollers.

6. The dry film forming apparatus according to claim 2, wherein The side of the composite roller away from the film forming roller is a film discharging side, the dry film forming device further comprises a winding and unwinding mechanism, the winding and unwinding mechanism comprises a winding roller and an unwinding roller, a current collector roll is wound on the unwinding roller, the winding and unwinding mechanism is configured to unwind the current collector roll by the unwinding roller to release the current collector, and the current collector extends in the direction from the unwinding roller to the winding roller until being wound by the winding roller, a second gap is formed between the current collector and the film discharging side, the finished film piece passes through the second gap and is bonded to the current collector in the second gap.

7. The dry film forming apparatus according to claim 6, wherein The film forming mechanism and the feeding mechanism are both provided with two, the two film forming mechanisms are symmetrically distributed with the extension direction of the current collector as the center, and the film discharging sides of the composite rollers of the two film forming mechanisms are both provided with the second gap between the film discharging sides and the current collector, and each of the film forming mechanisms corresponds to one feeding mechanism.

8. The dry film forming apparatus according to claim 2, wherein The film forming mechanism and the feeding mechanism are both provided with one, the dry film forming device further comprises a pressing roller, the pressing roller is located on the side of the composite roller away from the film forming roller, a third gap is formed between the pressing roller and the composite roller, and the third gap is used for the current collector and the finished film piece to pass through simultaneously.

9. The dry film forming apparatus according to claim 1, wherein The feeding part comprises two first baffles arranged oppositely, a second baffle located between the two first baffles and connected with the two first baffles, and the spreading roller is partially located between the two first baffles and forms the feeding channel between the spreading roller and the second baffle.

10. The dry film forming apparatus according to claim 9, wherein The second baffle is arranged obliquely, and the distance between the second baffle and the feeding port is greater than the distance between the second baffle and the discharging port.

11. The dry film forming apparatus according to claim 10, wherein The second baffle is arranged obliquely along a first direction, an included angle between the first direction and a horizontal plane is 40°-80°, and / or a vertical distance between the second baffle and a center point of the spreading roller is 100-600 mm.

12. The dry film forming apparatus according to claim 2, wherein The feeding part and the spreading roller are each internally provided with a cooling interlayer for passing in a cooling medium; and / or The film forming roller, the calender roller and the composite roller are each internally provided with a heating assembly for heating the film forming roller, the calender roller and the composite roller.

13. The dry film forming apparatus according to claim 2, wherein A size of the second roller gap is 0.01-1 mm, and / or an outer diameter size of the film forming roller is 200-1200 mm, and / or an outer diameter size of the calender roller is 80-600 mm, and / or an outer diameter size of the composite roller is 200-1200 mm, and / or an outer diameter size of the spreading roller is 80-300 mm, and / or a size of the first roller gap is 1-10 mm.

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