Coating roller, and preparation device and preparation method of solid electrolyte coating of battery pole piece

Abstract

The invention provides a coating roller, and a preparation device and a preparation method of a solid electrolyte coating of a battery pole piece, and belongs to the field of batteries. When the extending direction of the rotating axis of the roller is the axial direction of the roller, a plurality of channels are tightly formed in the peripheral wall of the roller in the axial direction of the roller, surround the axial direction of the roller and are connected end to end, the channels extend in a wavy curve mode, and a plurality of grooves are tightly formed in the channels in the extending direction of the two ends of the channels. And the plurality of grooves and the plurality of channels form an ink cell structure on the peripheral surface of the roller. The ink cell structure formed by the wave curve channel and the groove array is designed on the peripheral surface of the coating roller, so that stable and continuous film-shaped transfer of slurry can be formed on the roller surface, local stress concentration is reduced, a pole piece is stressed more uniformly during transfer printing, the requirement on tension is remarkably reduced, and the risk of belt breakage is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery, in particular to a coating roller, a solid electrolyte coating preparation device and preparation method for battery pole piece. BACKGROUND

[0002] At present, the solid electrolyte is coated on the surface of the positive and negative pole pieces by using the micro-gravure reverse coating method. For example, the Chinese patent CN104275268A discloses a surface coating device and method for lithium battery pole piece or separator. The coating paste is immersed on the surface of the gravure roller in a closed tray, the paste is stirred by rotating the gravure roller, the roller surface is covered with the paste, the surface paste is scraped off by the scraper, the paste in the mesh hole is left, and the pole piece is pushed to the plate roller by the approaching roller, so that the paste is transferred to the surface of the pole piece. However, the existing technology has the following disadvantages: the current gravure roller is a mesh roller, and when the pole piece contacts the roller surface to transfer the paste, the tension requirement of the pole piece is high, which leads to the problem of easy breakage of the pole piece. SUMMARY

[0003] Therefore, the present application provides a coating roller, a solid electrolyte coating preparation device and preparation method for battery pole piece, which solves the problem of high tension requirement of the pole piece when the current gravure roller contacts the pole piece to transfer the paste.

[0004] The technical scheme of the present application is as follows: the present application provides a coating roller, which comprises a roller barrel; when the extension direction of the rotation axis of the roller barrel is the axial direction of the roller barrel, a plurality of channels are closely arranged on the outer peripheral wall of the roller barrel along the axial direction of the roller barrel, the channels are connected end to end around the axial direction of the roller barrel, the channels extend in a wavy curve, a plurality of grooves are closely arranged in the channels along the extension direction of the two ends of the channels, and the plurality of grooves and the plurality of channels form a mesh structure on the outer peripheral surface of the roller barrel.

[0005] Preferably, the extension curve of the channel is a sine curve or a cosine curve.

[0006] Preferably, the shape of the groove is circular or regular polygon.

[0007] Preferably, the width of the channel is the same as that of the groove, and the sum of the depths of the channel and the groove is 23% to 33% of the width of the channel.

[0008] More preferably, the sum of the depths of the channel and the groove is 45 to 50 microns.

[0009] Preferably, the bottom surface of the groove is a concave conical surface.

[0010] In a second aspect, the present application also provides a solid electrolyte coating preparation device for battery electrode sheet, which adopts the coating roller described above, and further comprises a tray, a scraper and a transfer roller; the tray is filled with slurry, the roller is arranged in the tray, the lower half of the roller is immersed in the slurry, the roller shaft is rotated and the slurry is adhered to the outer circumferential surface of the roller; the scraper is arranged on one side of the roller in the axial direction, when the roller shaft is rotated, the end of the scraper is in contact with the outer circumferential surface of the roller, and the scraper scrapes the slurry outside the mesh hole structure on the outer circumferential surface of the roller; the transfer roller is arranged directly above the roller, the electrode sheet is clamped between the roller surface of the transfer roller and the outer circumferential surface of the roller, the transfer roller is simultaneously rotated with the roller shaft, the rotation direction of the transfer roller is opposite to that of the roller, and the transfer roller is used to press the electrode sheet onto the roller and transfer the slurry to the surface of the electrode sheet.

[0011] Preferably, the viscosity of the slurry is 500-3000 mPa·s.

[0012] More preferably, when the viscosity of the slurry increases, the wavelength of the wavy curve of the channel extension increases, and the width of the channel increases; when the viscosity of the slurry decreases, the wavelength of the wavy curve of the channel extension decreases, and the width of the channel decreases.

[0013] In a third aspect, the present application also provides a solid electrolyte coating preparation method for battery electrode sheet, which adopts the solid electrolyte coating preparation device for battery electrode sheet described above, and comprises the following steps: step one, the lower half of the roller is immersed in the slurry, so that the slurry in the tray infiltrates the outer circumferential surface of the roller; step two, the roller shaft is rotated and the slurry is stirred, so that the outer circumferential surface of the roller is fully covered with the slurry, the scraper scrapes the surface layer of the slurry on the outer circumferential surface of the roller, and only the slurry in the mesh hole structure is left; step three, the electrode sheet moves forward and passes between the transfer roller and the roller, the transfer roller is used to press the electrode sheet onto the roller, and the slurry is transferred to the surface of the electrode sheet.

[0014] The coating roller, the solid electrolyte coating preparation device and the preparation method for battery electrode sheet of the present application have the following advantages over the prior art: (1) The mesh hole structure formed by the wavy curve channel and the groove array on the outer circumferential surface of the coating roller of the present application can make the slurry form a stable and continuous film on the roller surface, reduce local stress concentration, make the electrode sheet bear force more evenly during transfer, significantly reduce the requirement for tension, and reduce the risk of belt breakage. The channel and the groove together determine the distribution of the slurry per unit area, so that the slurry is transferred in a continuous film during transfer, avoiding the defects of traditional mesh roller such as stripes, boundaries and pinholes, making the coating thinner and more uniform, and more suitable for precise coating of solid electrolyte, making the slurry distribution uniform and the thickness controllable, and the solidified solid electrolyte coating more dense and the electrode sheet surface more evenly covered, which helps to improve the anti-micro short circuit performance and mechanical extrusion stability.

[0015] (2) the wave curve channel in the net hole structure of the application enhances the internal flowability of the slurry, helps to form a smooth material conveying path, reduces the particle blockage in the solid slurry, and improves the compatibility of high-viscosity slurry; the closed and symmetrical groove structure maintains good liquid storage stability and does not cause overflow due to scraper pressure. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0017] Figure 1 Structure diagram of the solid electrolyte coating preparation device of the present application; Figure 2 Stereogram of the net hole structure on the surface of the coating roller of the present application; Figure 3 Top view of the net hole structure on the surface of the coating roller of the present application; Figure 4 Sectional view of the net hole structure on the surface of the coating roller of the present application.

[0018] In the figure: 1, roller; 10, net hole structure; 11, channel; 12, groove; 2, tray; 3, slurry; 4, scraper; 5, transfer roller; 6, pole piece. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present application more clear, the technical solutions in the present application will be described clearly and completely in the following with reference to the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0020] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0021] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0024] The following disclosure provides numerous different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. Additionally, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0025] like Figure 1 As shown, combined with Figure 2 and Figure 3The present invention discloses a coating roller, comprising a roller 1. When the rotation axis of the roller 1 extends along its axial direction, a plurality of channels 11 are tightly formed on the outer peripheral wall of the roller 1 along its axial direction. The channels 11 surround the axial direction of the roller 1 and are connected end-to-end. The channels 11 extend in a wavy curve. A plurality of grooves 12 are tightly formed within the channels 11 along their two ends. The grooves 12 and the channels 11 form a mesh structure 10 on the outer peripheral surface of the roller 1. The wavy shape of the channels 11 allows the slurry 3 to flow more smoothly through the channels 11, resulting in stronger fluidity of the slurry 3 during material transfer. This is because the wavy channel 11 enables the slurry 3 to form a continuous "film transfer" during transfer, resulting in a coating without obvious boundaries and a smoother coating surface. Simultaneously, the enhanced fluidity within the channels 11 makes them less prone to clogging, reducing defects such as "missed coating" and "pinholes" caused by clogging of the mesh structure 10. This also improves the adaptability to slurries 3 with slightly higher viscosity or containing small particles. When grooves 12 are arranged within channel 11, grooves 12 provide secondary liquid storage space. Grooves 12 have a closed symmetrical structure (e.g., circular or regular polygonal), which provides strong stability for storing slurry 3 and makes it less likely for slurry 3 to overflow prematurely due to external forces (e.g., doctor blade pressure). Through the above methods, the thickness of slurry 3 after transfer is thinner and the distribution of slurry 3 per unit area is more uniform, which is suitable for precise coating of ultra-thin coatings. The ultra-thin and continuous slurry 3 coating has stronger adhesion to the substrate surface, and the coating is denser after curing, which can more uniformly cover the surface of electrode 6, reduce electrolyte penetration channels, and provide better protection for electrode 6 such as "anti-micro-short circuit" and "anti-extrusion". In addition, the double-layer structure formed by channel 11 and groove 12 reduces the viscosity sensitivity of slurry 3, improves the viscosity compatibility range of slurry 3, and avoids the flow problems that are prone to occur with high viscosity slurry 3. For low viscosity slurry 3, a smaller width of channel 11 can be used to avoid the problem of slurry volume runaway.

[0026] exist Figure 3 In one embodiment shown, the extension curve of channel 11 is a sine or cosine curve. The sine / cosine waveform has mathematical continuity and smoothness, causing channel 11 to exhibit periodic curvature changes, thereby enhancing the disturbance capability of slurry 3. This helps to improve the adaptive flowability of the cell structure 10 on the surface of roller 1, reducing defects such as "straight lines" and "boundary lines" in the coating, thus achieving uniform coating thickness.

[0027] exist Figure 3 In one embodiment shown, the groove 12 is circular or a regular polygon. Therefore, the groove 12 has two properties: First, the groove 12 has a closed and symmetrical structure. Therefore, as a secondary liquid outlet space, the groove 12 can store the slurry 3 stably and is not prone to flow deviation. Second, there are no sharp corners in the groove 12. Therefore, the slurry 3 is not prone to accumulation and blockage during transfer.

[0028] existFigure 4 In one embodiment shown, the width of the channel 11 and the groove 12 are the same, so that the thickness of the paste 3 coating is consistent; the sum of the depths of the channel 11 and the groove 12 is 23% to 33% of the width of the channel 11. Its function is to balance the liquid storage and the cleaning ability of the doctor blade 4. If the depth is too deep, the paste 3 in the channel 11 will not be fully discharged during the transfer, thus weakening the transfer effect. If the depth is too shallow, the paste 3 in the channel 11 will not be stored enough, which is also not conducive to improving the transfer effect.

[0029] exist Figure 4 In one embodiment shown, the sum of the depths of the channel 11 and the groove 12 is 45~50μm. This depth is suitable as a target thickness reference for solid electrolyte coating, which can achieve the effect of "achieving an ultra-thin coating in a single transfer".

[0030] exist Figure 4 In one embodiment shown, the bottom surface of the groove 12 is a concave conical surface, which allows the paste 3 to maintain natural central contraction and avoids paste overflow at the edge of the groove 12; it also allows the paste 3 to be released quickly during transfer, preventing paste 3 from accumulating in the groove 12 and improving the self-cleaning property of the cell structure 10.

[0031] like Figure 1 As shown, the solid electrolyte coating preparation apparatus for battery electrode sheets of the present invention uses the above-mentioned coating roller and further includes a material tray 2, a doctor blade 4, and a transfer roller 5; the material tray 2 contains slurry 3, the roller 1 is disposed in the material tray 2, the lower half of the roller 1 is immersed in the slurry 3, the roller 1 rotates and the slurry 3 adheres to the outer circumferential surface of the roller 1; the doctor blade 4 is disposed on one side of the roller 1 in the axial direction, and the function of the doctor blade 4 is to remove excess slurry 3. When the roller 1 rotates... The end of the scraper 4 contacts the outer circumferential surface of the roller 1, scraping away the slurry 3 outside the cell structure 10 on the outer circumferential surface of the roller 1. The transfer roller 5 is positioned directly above the roller 1. The transfer roller 5 is generally a rubber roller. The electrode sheet 6 is clamped between the roller surface of the transfer roller 5 and the outer circumferential surface of the roller 1. The transfer roller 5 rotates simultaneously with the roller 1, but in the opposite direction to the roller 1. The transfer roller 5 presses the electrode sheet 6 onto the roller 1 and transfers the slurry 3 onto the surface of the electrode sheet 6. The transfer roller 5 and the roller 1 with the cell structure 10 clamp the electrode sheet 6, creating a tension barrier on the surface of the electrode sheet 6. This reduces the tension on the electrode sheet 6, making it less likely for the electrode sheet 6 to break, produce two or more electrodes at once, and avoiding the risk of wrinkles or gaps in the middle of the electrode sheet 6.

[0032] exist Figure 1 In one embodiment shown, the viscosity of slurry 3 is 500~3000 mPa·s, which is consistent with the typical rheological characteristics of solid electrolyte slurries.

[0033] exist Figure 3In one embodiment shown, when the viscosity of the slurry 3 increases, the wavelength of the wave curve of the channel 11 increases and the width of the channel 11 increases, which reduces the flow resistance of the slurry 3; when the viscosity of the slurry 3 decreases, the wavelength of the wave curve of the channel 11 decreases and the width of the channel 11 decreases, which prevents the slurry 3 from experiencing uncontrolled fluctuations.

[0034] like Figure 1 As shown, the present invention discloses a method for preparing a solid electrolyte coating for a battery electrode using the aforementioned apparatus for preparing a solid electrolyte coating for a battery electrode. The method includes the following steps: Step 1, the lower half of the roller 1 is immersed in the slurry 3, so that the slurry 3 in the tray 2 wets the outer circumferential surface of the roller 1; Step 2, the roller 1 rotates and stirs the slurry 3, so that the outer circumferential surface of the roller 1 is covered with the slurry 3, and the scraper 4 scrapes off the surface slurry 3 on the outer circumferential surface of the roller 1, leaving only the slurry 3 located in the cell structure 10; Step 3, the electrode 6 moves forward and passes between the transfer roller 5 and the roller 1, the transfer roller 5 presses the electrode 6 onto the roller 1, and the slurry 3 is transferred onto the surface of the electrode 6.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A coating roller, characterized in that: Includes a roller (1); when the direction of the rotation axis of the roller (1) is taken as the axial direction of the roller (1), a plurality of channels (11) are tightly opened on the outer peripheral wall of the roller (1) along the axial direction of the roller (1), the channels (11) surround the axial direction of the roller (1) and are connected end to end, the channels (11) extend in a wavy curve, and a plurality of grooves (12) are tightly opened in the channel (11) along the extension direction of both ends of the channel (11), the plurality of grooves (12) and the plurality of channels (11) form a mesh structure (10) on the outer peripheral surface of the roller (1).

2. A coating roller according to claim 1, characterized in that: The extension curve of the channel (11) is a sine curve or a cosine curve.

3. A coating roller according to claim 1, characterized in that: The groove (12) is circular or regular polygonal in shape.

4. A coating roller according to claim 1, characterized in that: The channel (11) and the groove (12) have the same width, and the sum of the depths of the channel (11) and the groove (12) is 23% to 33% of the width of the channel (11).

5. A coating roller according to claim 4, characterized in that: The sum of the depths of the channel (11) and the groove (12) is 45~50μm.

6. A coating roller according to claim 1, characterized in that: The bottom surface of the groove (12) is an inwardly concave conical surface.

7. An apparatus for preparing a solid electrolyte coating for battery electrodes, characterized in that: The coating roller described in any one of claims 1 to 6 further includes a material tray (2), a doctor blade (4), and a transfer roller (5). The tray (2) contains slurry (3), the roller (1) is set inside the tray (2), the lower half of the roller (1) is immersed in the slurry (3), the roller (1) rotates and causes the slurry (3) to adhere to the outer circumferential surface of the roller (1); The scraper (4) is located on one side of the roller (1) in the axial direction. When the roller (1) rotates, the end of the scraper (4) abuts against the outer circumferential surface of the roller, and the scraper (4) scrapes off the slurry (3) located outside the mesh structure (10) on the outer circumferential surface of the roller (1). The transfer roller (5) is positioned directly above the roller (1). An electrode sheet (6) is clamped between the roller surface of the transfer roller (5) and the outer circumferential surface of the roller (1). The transfer roller (5) rotates simultaneously with the roller (1). The rotation direction of the transfer roller (5) is opposite to that of the roller (1). The transfer roller (5) presses the electrode sheet (6) onto the roller (1) and transfers the paste (3) onto the surface of the electrode sheet (6).

8. The apparatus for preparing a solid electrolyte coating for a battery electrode according to claim 7, characterized in that: The viscosity of the slurry (3) is 500~3000 mPa·s.

9. The apparatus for preparing a solid electrolyte coating for a battery electrode according to claim 8, characterized in that: When the viscosity of the slurry (3) increases, the wavelength of the wave curve of the channel (11) increases and the width of the channel (11) increases; when the viscosity of the slurry (3) decreases, the wavelength of the wave curve of the channel (11) decreases and the width of the channel (11) decreases.

10. A method for preparing a solid electrolyte coating for a battery electrode, characterized in that: The apparatus for preparing a solid electrolyte coating for a battery electrode according to any one of claims 7 to 9 includes the following steps: Step 1: The lower half of the roller (1) is immersed in the slurry (3), so that the slurry (3) in the material tray (2) wets the outer circumference of the roller (1); Step 2: The roller (1) rotates and stirs the slurry (3) so that the outer circumferential surface of the roller (1) is covered with slurry (3). The scraper (4) scrapes off the surface slurry (3) on the outer circumferential surface of the roller (1), leaving only the slurry (3) located in the mesh structure (10). Step 3: The electrode (6) moves forward and passes between the transfer roller (5) and the roller (1). The transfer roller (5) presses the electrode (6) onto the roller (1) and transfers the paste (3) onto the surface of the electrode (6).

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