A gravure liquid injection process

Abstract

The present invention provides a gravure liquid injection process, which belongs to the technical field of lithium batteries. The gravure liquid injection process provided by the present invention comprises the following steps: S1, adding additives to the electrolyte in advance to increase the viscosity of the electrolyte to more than 4000 pa.s; S2, adding two liquid injection and coating stations on a winding machine or a stacking machine, and arranging a gravure coating device for coating the positive electrode sheet or the negative electrode sheet with electrode liquid on the corresponding station; S3, the positive electrode sheet and the negative electrode sheet are double-sided gravure coated through the corresponding gravure coating device; S4, the electrode sheet after coating is wound or stacked. The present invention can double-sidedly coat the electrode sheet during the winding or stacking process, greatly reducing the cumbersomeness of subsequent liquid injection in the battery shell, optimizing the lithium battery production process, and improving the stability of the lithium battery production quality.

Description

Technical Field

[0001] The invention belongs to the technical field of lithium batteries, and more specifically, relates to a gravure liquid injection process. Background Art

[0002] Lithium batteries are a type of battery that uses lithium metal or lithium alloy as the positive / negative electrode material and a non-aqueous electrolyte solution. They include the lithium-sulfur battery, which is currently a research hotspot, and the widely used lithium-ion battery. Both are composed of a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte.

[0003] In the lithium battery production process, the wound or stacked battery cells need to be loaded into the battery shell, and then the electrolyte is injected into the battery shell. However, the electrolyte often appears in the battery cell and the battery material is not fully and evenly impregnated, affecting the quality of lithium battery production. Summary of the invention

[0004] The purpose of the present invention is to provide a gravure injection process to solve the technical problem in the prior art that the electrolyte often appears in the battery cell and the battery cell material is not fully and uniformly impregnated, which affects the production quality of lithium batteries.

[0005] To achieve the above object, the technical solution adopted by the present invention is: to provide a gravure liquid injection process, comprising the following steps:

[0006] S1. Add additives to the electrolyte in advance to increase the viscosity of the electrolyte to more than 4000 Pa.s;

[0007] S2. Add two liquid injection and coating stations on the winding machine or the stacking machine, and set a gravure coating device for coating the positive electrode sheet or the negative electrode sheet with electrode liquid on the corresponding stations;

[0008] S3, the positive electrode sheet and the negative electrode sheet are double-sided gravure coated by corresponding gravure coating devices;

[0009] S4. After coating, the electrode sheets are wound or stacked.

[0010] In combination with the above technical solution, in a possible implementation, in S1, the additive is PVDF powder in a proportion of 5%-10% of the original electrolyte formula.

[0011] In combination with the above technical scheme, in a possible implementation method, the gravure coating device includes a liquid reservoir, a lower gravure roller, a sealing shell, an upper gravure roller and a liquid supply assembly, the liquid reservoir is arranged on the liquid injection and coating station; the lower gravure roller is rotatably connected to the top opening of the liquid reservoir, and a scraper close to the outer peripheral surface of the lower gravure roller is arranged in the liquid reservoir; the sealing shell is arranged above the liquid reservoir and is a lower opening; the upper gravure roller is rotatably connected to the bottom opening of the sealing shell, the pole piece passes between the lower gravure roller and the upper gravure roller, and the outer peripheral surface of the lower gravure roller and the side of the lower opening of the sealing shell facing the direction of transmission of the pole piece have a gap for electrolyte to pass through; the liquid supply assembly is arranged between the liquid reservoir and the sealing shell, and the liquid supply assembly is used to supply the electrolyte in the liquid reservoir into the sealing shell.

[0012] In combination with the above technical solution, in a possible implementation method, a liquid guide plate located directly above the upper gravure roller is arranged at the top of the sealing shell, and a plurality of liquid guide plates facing the grooves on the outer peripheral surface of the lower gravure roller are arranged at the bottom of the liquid guide plate, and the liquid supply assembly is used to draw the electrolyte in the liquid storage tank onto the liquid guide plate.

[0013] In combination with the above technical solution, in a possible implementation method, a rubber pressing roller parallel to the upper gravure roller is rotatably connected in the sealing shell, the outer peripheral surface of the rubber pressing roller abuts against the outer peripheral surface of the upper gravure roller, the rubber pressing roller is located on the rear side of the liquid guide plate along the rotation direction of the upper gravure roller, the rotation direction of the rubber pressing roller is opposite to the rotation direction of the upper gravure roller, and a driving motor for driving the rubber pressing roller to rotate is arranged on the outside of the sealing shell.

[0014] In combination with the above technical solution, in a possible implementation, the liquid supply assembly includes a liquid supply pump, a liquid supply tube and a liquid dispensing tube, the liquid supply pump is connected to the outside of the liquid storage tank; one end of the liquid supply tube is connected to the liquid supply pump, and the other end extends to the top of the sealed shell; the liquid dispensing tubes are arranged in the sealed shell and are connected to the liquid supply tubes, and the outlet end of each of the liquid dispensing tubes faces the liquid guide plate corresponding to the position above the liquid guide sheet.

[0015] In combination with the above technical solution, in a possible implementation, the gravure coating device also includes a collecting tank and a scraping mechanism, the collecting tank is arranged below the lower opening of the sealing shell and the side of the upper gravure roller toward the pole piece passing out direction, and the upper gravure roller is in contact with the side of the lower opening of the sealing shell toward the pole piece passing out direction; the collecting tank is arranged at an angle, and the bottom end of the collecting tank is located directly above the position of the liquid storage tank that does not pass the pole piece; the scraping mechanism is arranged at the bottom of the sealing shell, and the scraping mechanism is used to scrape the electrolyte in the collecting tank into the liquid storage tank.

[0016] In combination with the above technical solution, in a possible implementation method, the scraping mechanism includes a scraping screw, a polished rod, a scraping motor, a threaded block and a scraper, the scraping screw is rotatably connected under the sealing shell and parallel to the length direction of the collecting tank; the polished rod is fixed under the sealing shell and parallel to the scraping screw; the scraping motor is arranged under the sealing shell, and the scraping motor output shaft is coaxially fixed with the scraping screw; the threaded block is threadedly connected to the scraping screw and penetrated by the polished rod; the scraper is arranged on the threaded block and is used to scrape the electrolyte in the collecting tank.

[0017] In combination with the above technical solution, in a possible implementation method, the scraping mechanism also includes a rotating shaft, a linkage screw and a one-way limiter; the rotating shaft is rotatably connected to the threaded block, one end of the scraper is fixed to the rotating shaft, and the other end of the scraper is attached to the inner wall of the collection tank; the linkage screw has two ends arranged below the sealing shell, the linkage screw is parallel to the scraping screw, and threaded holes for the corresponding linkage screws to enter are opened at both ends of the rotating shaft; the threaded block drives the rotating shaft and the linkage screw at the bottom end of the collection tank When the rod is threadedly connected, the scraper rotates upward to disengage from the collecting trough; when the threaded block drives the rotating shaft to be threadedly connected with the linkage screw at the top of the collecting trough, the scraper rotates downward to fit into the collecting trough again; the rotational friction between the rotating shaft and the threaded block is greater than the sum of the weight of the scraper and the thread friction between the rotating shaft and the linkage screw; there are two one-way limit members and they are arranged at the corresponding linkage screws, and the one-way limit members are used to limit the linkage screw to rotate only when the thread is screwed into the threaded hole of the rotating shaft.

[0018] In combination with the above technical solution, in a possible implementation manner, the one-way limiter is a one-way bearing, and the one-way limiter is arranged at the rotation connection between the linkage screw and the bottom of the sealing shell.

[0019] The beneficial effect of the gravure liquid injection process provided by the present invention is that: compared with the prior art, the present invention can double-sided coat the pole piece during the winding or lamination process, and increase the viscosity of the electrolyte through additives, so that the electrolyte can be more stably coated on the pole piece, greatly reducing the tediousness of subsequent liquid injection in the battery shell, optimizing the lithium battery production process, and improving the stability of the lithium battery production quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0021] Figure 1 It is a schematic diagram of a process of applying an embodiment of the present invention in a laminating machine;

[0022] Figure 2 A schematic diagram of the structure of a gravure coating device provided in an embodiment of the present invention;

[0023] Figure 3 A cross-sectional view of a gravure coating device provided by an embodiment of the present invention;

[0024] Figure 4 A right side view of a gravure coating device provided by an embodiment of the present invention;

[0025] Figure 5 A schematic structural diagram of a scraping mechanism provided in an embodiment of the present invention.

[0026] Among them, the reference numerals in the figures are as follows:

[0027] 1. Liquid storage tank; 11. Scraper;

[0028] 2. Lower gravure roller;

[0029] 3. Sealing shell; 31. Liquid guide plate; 32. Liquid guide sheet; 33. Rubber pressing roller; 34. Driving motor;

[0030] 4. Upper gravure roller;

[0031] 5. Liquid supply assembly; 51. Liquid supply pump; 52. Liquid supply pipe; 53. Liquid dispensing pipe;

[0032] 6. Collection tank;

[0033] 7. Scraping mechanism; 71. Scraping screw; 72. Polished rod; 73. Scraping motor; 74. Threaded block; 75. Scraper; 76. Rotating shaft; 761. Threaded hole; 77. Linkage screw; 78. One-way limiter;

[0034] 8. Battery positive electrode; 9. Battery negative electrode; 10. Diaphragm. DETAILED DESCRIPTION

[0035] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the described embodiments are only part of the embodiments of the present application, rather than all the embodiments, and the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.

[0036] It should be further explained that the drawings and implementation modes of the present invention mainly describe the concept of the present invention. On the basis of this concept, the specific forms and settings of some connection relationships, positional relationships, power mechanisms, power supply systems, hydraulic systems and control systems may not be fully described. However, on the premise that those skilled in the art understand the concept of the present invention, those skilled in the art can implement the above-mentioned specific forms and settings in a well-known manner.

[0037] When an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element.

[0038] The directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself. The directions or positional relationships indicated by the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the directions or positional relationships shown in the drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0039] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways, and the spatially relative descriptions used here are interpreted accordingly.

[0040] In the prior art, a lithium battery winding machine is a device specifically used for lithium battery production. Its core function is to assemble the positive electrode sheet 8, the negative electrode sheet 9 and the separator 10 into a core package in a continuous rotation manner to form a lithium battery cell. A lithium battery stacking machine is a device specifically used for manufacturing lithium-ion batteries. It is mainly used to accurately stack the positive electrode sheet 8, the negative electrode sheet 9 and the separator 10 in a certain order and number of layers to form a battery cell, such as Figure 1 shown.

[0041] A gravure liquid injection process provided by the present invention is now described.

[0042] An embodiment of the present invention provides a gravure liquid injection process, comprising the following steps: S1, adding additives to the electrolyte in advance to increase the viscosity of the electrolyte to more than 4000 Pa.s; S2, adding two liquid injection and coating stations on a winding machine or a stacking machine, and arranging a gravure coating device for coating the positive electrode sheet or the negative electrode sheet with electrode liquid on the corresponding station; S3, the positive electrode sheet and the negative electrode sheet are double-sided gravure coated by the corresponding gravure coating device; S4, the electrode sheets after coating are wound or stacked.

[0043] Specifically, the additive is PVDF powder in a proportion of 5%-10% of the original electrolyte formula.

[0044] Compared with the prior art, the gravure liquid injection process provided in this embodiment can double-sidedly coat the pole piece during the winding or lamination process, and increase the viscosity of the electrolyte through additives so that the electrolyte can be more stably coated on the pole piece, greatly reducing the tediousness of subsequent liquid injection in the battery shell, optimizing the lithium battery production process, and improving the stability of the lithium battery production quality.

[0045] like Figures 2 to 3 As shown, the present invention provides a specific implementation method based on the above implementation method as follows:

[0046] The gravure coating device comprises a liquid reservoir 1, a lower gravure roller 2, a sealing shell 3, an upper gravure roller 4 and a liquid supply assembly 5; the liquid reservoir 1 is arranged on a liquid injection and coating station; the lower gravure roller 2 is rotatably connected to the top opening of the liquid reservoir 1, and a scraper 11 close to the outer peripheral surface of the lower gravure roller 2 is arranged in the liquid reservoir 1; the sealing shell 3 is arranged above the liquid reservoir 1 and is a lower opening; the upper gravure roller 4 is rotatably connected to the bottom opening of the sealing shell 3, and the pole piece passes between the lower gravure roller 2 and the upper gravure roller 4, and a gap is provided on the outer peripheral surface of the lower gravure roller 2 and the side of the lower opening of the sealing shell 3 facing the direction of transmission of the pole piece for electrolyte to pass through; the liquid supply assembly 5 is arranged between the liquid reservoir 1 and the sealing shell 3, and the liquid supply assembly 5 is used to supply the electrolyte in the liquid reservoir 1 into the sealing shell 3.

[0047] When double-sided coating of the electrode piece is performed, the electrode piece passes between the lower gravure roller 2 and the upper gravure roller 4, and part of the outer circumference of the lower gravure roller 2 and the upper gravure roller 4 is immersed in the electrolyte in the liquid reservoir 1 and the sealing shell 3. The rotation of the lower gravure roller 2 and the upper gravure roller 4 coats the electrolyte on both sides of the electrode piece. After the electrolyte in the sealing shell 3 becomes less, the liquid supply component 5 draws the electrolyte in the liquid reservoir 1 into the sealing shell 3. After the electrolyte in the liquid reservoir 1 becomes less, the staff pours the electrolyte into the liquid reservoir 1 to maintain the continuity of the operation, thereby improving the overall efficiency of simultaneous coating of both sides of the electrode piece.

[0048] like Figure 3 As shown, the present invention provides a specific implementation method based on the above implementation method as follows:

[0049] A liquid guide plate 31 is arranged at the top of the sealing shell 3 and is located directly above the upper gravure roller 4. A plurality of liquid guide sheets 32 are arranged at the bottom of the liquid guide plate 31 and are located at the grooves on the outer peripheral surface of the lower gravure roller 2. The liquid supply assembly 5 is used to draw the electrolyte in the liquid storage tank 1 onto the liquid guide plate 31.

[0050] The liquid supply component 5 continuously and slowly transports electrolyte into the sealing shell 3, and sends the electrolyte to the liquid guide plate 31. The electrolyte on the liquid guide plate 31 flows downward through each liquid guide plate 32 to the groove on the outer peripheral surface of the rotating upper gravure roller 4. The groove filled with the electrolyte is then rotated into the electrolyte, and the phenomenon of bubbles remaining in the groove on the outer peripheral surface of the upper gravure roller 4 after rotating in the electrolyte in the sealing shell 3 is avoided as much as possible, thereby improving the coating quality of the electrode.

[0051] like Figures 2 to 3 As shown, the present invention provides a specific implementation method based on the above implementation method as follows:

[0052] A rubber pressing roller 33 parallel to the upper gravure roller 4 is rotatably connected in the sealing shell 3, and the outer peripheral surface of the rubber pressing roller 33 abuts against the outer peripheral surface of the upper gravure roller 4. The rubber pressing roller 33 is located on the rear side of the liquid guide plate 31 along the rotation direction of the upper gravure roller 4. The rotation direction of the rubber pressing roller 33 is opposite to that of the upper gravure roller 4. A driving motor 34 is provided on the outside of the sealing shell 3 to drive the rubber pressing roller 33 to rotate.

[0053] Specifically, the side of the rubber pressing roller 33 facing away from the liquid guiding plate 31 is immersed in the electrolyte.

[0054] When the grooves on the outer surface of the upper gravure roller 4 are filled with electrolyte and rotate to the glue pressing roller 33, the driving motor 34 drives the glue pressing roller 33 to rotate so that the grooves on the outer surface of the upper gravure roller 4 can be infiltrated with electrolyte again. Before the grooves on the outer surface of the upper gravure roller 4 are rotated out of the sealing shell 3 for coating, they undergo three steps of liquid guide filling by the liquid guide plate 32, infiltration by the glue pressing roller 33 and electrolyte immersion, which further improves the gravure coating quality of the electrode.

[0055] like Figure 3 to Figure 4 As shown, the present invention provides a specific implementation method based on the above implementation method as follows:

[0056] The liquid supply assembly 5 includes a liquid supply pump 51, a liquid supply pipe 52 and a plurality of liquid distribution pipes 53; the liquid supply pump 51 is connected to the outside of the liquid storage tank 1; one end of the liquid supply pipe 52 is connected to the liquid supply pump 51, and the other end extends to the top of the sealed shell 3; the liquid distribution pipes 53 are arranged in the sealed shell 3 and are all connected to the liquid supply pipe 52, and the outlet end of each liquid distribution pipe 53 faces the liquid guide plate 31 at the position above the corresponding liquid guide sheet 32.

[0057] By starting the liquid supply pump 51, the electrolyte in the liquid storage tank 1 can be pumped into the liquid supply pipe 52, and then sprayed to the corresponding position of the liquid guide plate 31 above the corresponding liquid guide sheet 32 ​​through each liquid distribution pipe 53, thereby improving the electrolyte transportation efficiency.

[0058] like Figures 3 to 5 As shown, the present invention provides a specific implementation method based on the above implementation method as follows:

[0059] The gravure coating device also includes a collecting tank 6 and a scraping mechanism 7; the collecting tank 6 is arranged below the lower opening of the sealing shell 3 and the upper gravure roller 4 on the side facing the pole piece passing out, and the upper gravure roller 4 is in contact with the lower opening of the sealing shell 3 on the side facing the pole piece passing out; the collecting tank 6 is arranged at an angle, and the bottom end of the collecting tank 6 is located directly above the position of the liquid storage tank 1 that does not pass the pole piece; the scraping mechanism 7 is arranged at the bottom of the sealing shell 3, and the scraping mechanism 7 is used to scrape the electrolyte in the collecting tank 6 into the liquid storage tank 1.

[0060] The side of the lower opening of the sealing shell 3 facing the direction of the pole piece passing out can scrape the electrolyte from the outer peripheral surface of the upper gravure roller 4 after coating. On the one hand, the electrolyte can enter the groove on the outer peripheral surface of the upper gravure roller 4 again, which is convenient for the subsequent filling of the groove on the outer peripheral surface of the upper gravure roller 4. On the other hand, the electrolyte that cannot enter the groove on the outer peripheral surface of the upper gravure roller 4 in time falls into the inclined collection tank 6 and flows back to the liquid storage tank 1, which is beneficial to improve the coating quality of the pole piece and realize the recycling of the electrolyte. The scraping mechanism 7 can also scrape the electrolyte in the collection tank 6 regularly, improving the recycling effect of the electrolyte.

[0061] like Figures 3 to 5 As shown, the present invention provides a specific implementation method based on the above implementation method as follows:

[0062] The scraping mechanism 7 includes a scraping screw 71, a polished rod 72, a scraping motor 73, a threaded block 74 and a scraper 75; the scraping screw 71 is rotatably connected to the bottom of the sealing shell 3 and is parallel to the length direction of the collecting tank 6; the polished rod 72 is fixed to the bottom of the sealing shell 3 and is parallel to the scraping screw 71; the scraping motor 73 is arranged under the sealing shell 3, and the output shaft of the scraping motor 73 is coaxially fixed with the scraping screw 71; the threaded block 74 is threadedly connected to the scraping screw 71 and is penetrated by the polished rod 72; the scraper 75 is arranged on the threaded block 74 and is used to scrape the electrolyte in the collecting tank 6.

[0063] When the threaded block 74 and the scraper 75 are in the initial position, they are located at the top of the collecting tank 6. When the inside of the collecting tank 6 needs to be scraped, the scraping motor 73 is started to rotate the scraping screw 71. The scraping screw 71 drives the threaded block 74 and the scraper 75 to slide along the length direction of the light rod 72, so that the scraper 75 scrapes the electrolyte in the collecting tank 6 downwardly into the liquid storage tank 1, thereby improving the efficiency of scraping the electrolyte in the collecting chamber.

[0064] like Figures 3 to 5 As shown, the present invention provides a specific implementation method based on the above implementation method as follows:

[0065] The scraping mechanism 7 also includes a rotating shaft 76, a linkage screw 77 and a one-way limiter 78; the rotating shaft 76 is rotatably connected to the threaded block 74, one end of the scraper 75 is fixed to the rotating shaft 76, and the other end of the scraper 75 is attached to the inner wall of the collecting tank 6; the linkage screw 77 has two ends arranged at the bottom of the sealing shell 3, the linkage screw 77 is parallel to the scraping screw 71, and threaded holes 761 for the corresponding linkage screw 77 to enter are opened at both ends of the rotating shaft 76; when the threaded block 74 drives the rotating shaft 76 to be threadedly connected with the linkage screw 77 at the bottom end of the collecting tank 6, the scraper 7 5 is rotated upward to disengage from the collecting tank 6; when the threaded block 74 drives the rotating shaft 76 to be threadedly connected with the linkage screw 77 at the top of the collecting tank 6, the scraper 75 is rotated downward to fit into the collecting tank 6 again; the rotational friction between the rotating shaft 76 and the threaded block 74 is greater than the sum of the weight of the scraper 75 and the thread friction between the rotating shaft 76 and the linkage screw 77; there are two one-way limiters 78 and they are arranged at the corresponding linkage screws 77, and the one-way limiters 78 are used to limit the linkage screw 77 to rotate only when the thread is screwed into the threaded hole 761 of the rotating shaft 76.

[0066] The scraper 75 is moved out of the collecting tank 6 to avoid the phenomenon of pushing the electrolyte that subsequently falls into the collecting tank 6 upward. There is no need to stop the electrode coating operation when scraping the electrolyte in the collecting tank 6.

[0067] When the scraping motor 73 drives the scraping screw 71 to rotate so that the threaded block 74 and the scraper 75 move to the top of the collecting tank 6, the linkage screw 77 near the top of the collecting tank 6 is screwed into the threaded hole 761, and the angle of the scraper 75 remains unchanged at this time; when the collecting tank 6 needs to be scraped again, the threaded block 74 and the scraper 75 move toward the bottom of the collecting tank 6, and the one-way limit member 78 restricts the linkage screw 77 so that the scraper 75 rotates into the collecting tank 6 again, and the scraping motor 73 continues to drive the scraping screw 71 to rotate, thereby improving the scraping efficiency of the electrolyte in the collecting tank 6.

[0068] Specifically, a larger rotational friction force between the rotating shaft 76 and the threaded block 74 can be achieved through the interference fit between the two, which can improve the stability of scraping electrolyte inside the collecting tank 6 when the scraper 75 moves toward the bottom of the collecting tank 6, and can also improve the stability of the scraper 75 remaining outside the collecting tank 6 when it moves toward the top of the collecting tank 6.

[0069] Furthermore, the one-way stopper 78 is a one-way bearing, and the one-way stopper 78 is arranged at the rotation connection between the linkage screw 77 and the bottom of the sealing shell 3. The one-way stopper 78 adopts the one-way bearing to enable the linkage screw 77 to rotate in only one direction, which has good effect and low cost.

[0070] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A gravure liquid injection process, characterized in that: The following steps are involved: S1. Add additives to the electrolyte in advance to increase the viscosity of the electrolyte to more than 4000 Pa.s; S2. Add two liquid injection and coating stations on the winding machine or the stacking machine, and set a gravure coating device for coating the positive electrode sheet or the negative electrode sheet with electrode liquid on the corresponding stations; S3, the positive electrode sheet and the negative electrode sheet are double-sided gravure coated by corresponding gravure coating devices; S4, winding or laminating the electrode sheets after coating; The gravure coating device comprises: A liquid storage tank (1) is arranged on the liquid injection and coating station; A lower gravure roller (2) is rotatably connected to the top opening of the liquid storage tank (1), and a scraper (11) is provided in the liquid storage tank (1) close to the outer peripheral surface of the lower gravure roller (2); A sealing shell (3) is arranged above the liquid storage tank (1) and is open at the bottom; An upper gravure roller (4) is rotatably connected to the bottom opening of the sealing shell (3), and the pole piece passes between the lower gravure roller (2) and the upper gravure roller (4), and a gap is provided between the outer peripheral surface of the lower gravure roller (2) and the side of the lower opening of the sealing shell (3) facing the direction of pole piece introduction, for allowing electrolyte to pass through; A liquid supply assembly (5) is arranged between the liquid storage tank (1) and the sealed shell (3), and the liquid supply assembly (5) is used to supply the electrolyte in the liquid storage tank (1) into the sealed shell (3); The collecting groove (6) is arranged below the lower opening of the sealing shell (3) and the side of the upper gravure roller (4) facing the pole piece passing out direction, and the upper gravure roller (4) is in contact with the side of the lower opening of the sealing shell (3) facing the pole piece passing out direction; the collecting groove (6) is arranged obliquely, and the bottom end of the collecting groove (6) is located directly above the position of the liquid storage tank (1) that does not pass the pole piece; and a scraping mechanism (7) disposed at the bottom of the sealing shell (3), the scraping mechanism (7) being used to scrape the electrolyte in the collecting tank (6) into the liquid storage tank (1); The scraping mechanism (7) comprises: A scraping screw (71) is rotatably connected below the sealing shell (3) and parallel to the length direction of the collecting tank (6); A polished rod (72) fixed below the sealing shell (3) and parallel to the scraping screw (71); A scraping motor (73) is arranged below the sealing shell (3), and an output shaft of the scraping motor (73) is coaxially fixed with the scraping screw (71); a threaded block (74) threadably connected to the scraping screw (71) and penetrated by the polished rod (72); a scraper (75) disposed on the threaded block (74) and used to scrape the electrolyte in the collecting tank (6); A rotating shaft (76) is rotatably connected to the threaded block (74); one end of the scraper (75) is fixed to the rotating shaft (76); and the other end of the scraper (75) is attached to the inner wall of the collecting tank (6); The linkage screw (77) has two ends arranged below the sealing shell (3); the linkage screw (77) is parallel to the scraping screw (71); and threaded holes (761) are provided at both ends of the rotating shaft (76) for the corresponding linkage screw (77) to enter; when the threaded block (74) drives the rotating shaft (76) to be threadedly connected with the linkage screw (77) at the bottom end of the collecting tank (6), the scraper (75) rotates upward and separates from the collecting tank (6); when the threaded block (74) drives the rotating shaft (76) to be threadedly connected with the linkage screw (77) at the top end of the collecting tank (6), the scraper (75) rotates downward and fits into the collecting tank (6) again; the rotational friction between the rotating shaft (76) and the threaded block (74) is greater than the sum of the weight of the scraper (75) and the thread friction between the rotating shaft (76) and the linkage screw (77); and The one-way limiting members (78) have two and are arranged at positions corresponding to the linkage screw rod (77). The one-way limiting members (78) are used to limit the linkage screw rod (77) to rotate only when the thread is screwed into the threaded hole (761) of the rotating shaft (76).

2. A gravure liquid injection process as claimed in claim 1, characterized in that: In S1, the additive is PVDF powder at a ratio of 5%-10% of the original electrolyte formula.

3. A gravure liquid injection process as claimed in claim 1, characterized in that: A liquid guide plate (31) located directly above the upper gravure roller (4) is arranged at the top of the sealing shell (3), and a plurality of liquid guide plates (32) facing the grooves on the outer peripheral surface of the lower gravure roller (2) are arranged at the bottom of the liquid guide plate (31). The liquid supply assembly (5) is used to pump the electrolyte in the liquid storage tank (1) onto the liquid guide plate (31).

4. A gravure liquid injection process as claimed in claim 3, characterized in that: A rubber pressing roller (33) parallel to the upper gravure roller (4) is rotatably connected inside the sealing shell (3), the outer peripheral surface of the rubber pressing roller (33) abuts against the outer peripheral surface of the upper gravure roller (4), the rubber pressing roller (33) is located at the rear side of the liquid guide plate (31) along the rotation direction of the upper gravure roller (4), the rotation direction of the rubber pressing roller (33) is opposite to the rotation direction of the upper gravure roller (4), and a driving motor (34) for driving the rubber pressing roller (33) to rotate is arranged on the outer side of the sealing shell (3).

5. A gravure liquid injection process as claimed in claim 4, characterized in that: The liquid supply component (5) comprises: A liquid supply pump (51) connected to the outside of the liquid storage tank (1); a liquid supply pipe (52), one end of which is connected to the liquid supply pump (51), and the other end of which extends to the top of the sealed shell (3); and The liquid dispensing tubes (53) are arranged in the sealing shell (3) and are connected to the liquid supply tube (52); the outlet end of each of the liquid dispensing tubes (53) faces the liquid guide plate (31) at a position above the corresponding liquid guide plate (32).

6. A gravure liquid injection process as claimed in claim 1, characterized in that: The one-way limiting member (78) is a one-way bearing, and the one-way limiting member (78) is arranged at the rotation connection between the linkage screw rod (77) and the bottom of the sealing shell (3).

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