Back-up roll for coating electrode material having inflow air discharge function

Abstract

The present invention relates to a back-up roll for coating an electrode material having an inflow air discharge function. The present invention relates to an active material coating apparatus for manufacturing a secondary battery, which supports a current collector raw sheet while the coating apparatus coats an active material on the current collector raw sheet, and which comprises: a bonding surface portion bonded to the current collector raw sheet; and an exhaust guide part which is integrated with the bonding surface part and discharges the air flowing into the space between the support roller and the current collector raw sheet to the outside so as to prevent the current collector raw sheet from tilting due to the flowing air. According to the back-up roll for coating the electrode material with the inflow air discharge function, even if air flows between the back-up roll and the current collector raw sheet, the inflow air is immediately discharged, so that the current collector raw sheet is prevented from being tilted relative to the back-up roll, and the reliability of the back-up roll is improved. Therefore, an electrode material layer which is free of wrinkles and uniform in thickness can be coated.

Description

Technical Field

[0001] The present invention relates to an electrode material coating device for secondary batteries, and more particularly, to a support roller for electrode material coating with an inflow air discharge function, which prevents the collector sheet from warping relative to the support roller, thereby preventing the collector sheet and the electrode material layer from wrinkling and poor coating. Background Art

[0002] A secondary battery is a battery that can be repeatedly charged and discharged. It has a structure in which ions in an electrolyte move between an anode and a cathode insulated by a separator, thereby enabling repeated charge and discharge.

[0003] The electrodes in secondary batteries, namely the positive electrode and cathode, have a laminated structure consisting of a current collector and an electrode material layer. The current collector is a thin sheet or foil made of aluminum or copper. The electrode material layer is a laminate formed by applying a slurry of active material onto the current collector and then solidifying it. The resulting product of the active material after drying and solidification is the electrode material layer.

[0004] These secondary battery electrodes are produced by coating active material onto a current collector sheet, which is continuously supplied in a roll-to-roll process, followed by drying and curing. The coating device for layering the active material onto the current collector sheet consists of a back roll and a slot die. The slot die is positioned horizontally above the current collector sheet, squeezing the active material onto the sheet and layering it. The back roll, located below the slot die, supports the current collector sheet. Without the back roll, the current collector sheet would droop downward, preventing proper coating of the electrode active material.

[0005] Figure 1 This is a side view showing the appearance of a conventional support roller coating the active material on the collector sheet 11. Figure 2 1 is a plan view showing the appearance of an electrode material layer 13 stacked on a collector sheet. Figure 3 Is used to illustrate Figure 1 Diagram showing the problem of electrode layer coating device.

[0006] As shown in the figure, while the current collector sheet 11 passes between the active material coating device 15 and the support roller 17, the active material 12 supplied by the active material coating device 15 is coated on the upper surface of the current collector sheet 11. The coated active material 12 becomes the electrode material layer 13 after drying and curing. The support roller 17 is arranged in correspondence with the active material coating device 15 and supports the current collector sheet 11. Its surface is smooth.

[0007] For reference, Figure 2As shown, the electrode material layer 13 formed on the current collector sheet 11 is not formed over the entire surface of the current collector sheet 11. The electrode material layer is not formed at the widthwise ends and center of the current collector sheet. Specifically, if the portion of the current collector sheet 11 where the electrode material layer 13 is formed is referred to as the coated portion WA, and the portions where the electrode material layer 13 is not formed are referred to as the uncoated portions WO1 and WO2, the uncoated portions are formed at the widthwise center and at the widthwise ends of the current collector sheet 11. The width of the coated portion varies depending on the size of the secondary battery being manufactured.

[0008] However, there is a problem with the above-mentioned conventional active material coating device: Figure 3 As shown, during operation, a warping space Z is generated between the support roller 17 and the collector sheet 11. This warping space Z is formed when external air is drawn in along the direction of arrow a between the high-speed rotating support roller 17 and the collector sheet 11. This phenomenon is caused by friction between the air and the collector sheet 11, and between the air and the support roller 17. ( Figure 2 In the figure, the warping space Z is exaggerated for convenience. The maximum height H of the warping space may vary due to various reasons, but it is a fact that it occurs frequently.

[0009] The raised space Z causes the current collector sheet 11 to lift off the support roller 17, hindering accurate application of the active material 12. When the active material is applied while the current collector sheet 11 is raised, the thickness of the electrode material layer itself becomes uneven, resulting in irregular wrinkles. Furthermore, the current collector sheet also develops wrinkles.

[0010] Currently, a structure is required that, even if it is impossible to prevent air from entering between the current collector sheet 11 and the support roller 17, can immediately discharge the inflowing air to prevent the formation of a warping space.

[0011] As background art related to electrode material coating, Korean Patent Publication No. 10-2021-0069485 (Electrode Active Material Coating Apparatus for Secondary Battery) has been disclosed. Summary of the Invention

[0012] Technical issues

[0013] The present invention is created to solve the above problems, and its purpose is to provide a support roller for electrode material coating with an inflow air discharge function, which can prevent the collector sheet from warping relative to the support roller, thereby enabling the coating of a wrinkle-free and uniformly thick electrode material layer.

[0014] Technical Solution

[0015] As a technical solution to achieve the above-mentioned purpose, the present invention provides a support roller for coating electrode materials with a function of discharging inflowing air, which is configured to correspond to an active material coating device for secondary battery production, and supports the collector original sheet while the coating device coats the active material on the collector original sheet. The support roller for coating electrode materials with a function of discharging inflowing air includes: a fitting surface portion, which is fitted with the collector original sheet; and an exhaust guide portion, which is integrated with the fitting surface portion and discharges the air flowing between the support roller and the collector original sheet to the outside to prevent the collector original sheet from warping due to the inflowing air.

[0016] Furthermore, the current collector sheet includes a coated portion, which is a region coated with an active material, and an uncoated portion, which is a region not coated with the active material, and the exhaust guide is located at a position corresponding to the uncoated portion.

[0017] Furthermore, the exhaust guide portion includes an annular groove having a predetermined width and depth, extending in the circumferential direction of the support roller, and guiding the inflowing air in the circumferential direction.

[0018] In addition, the annular grooves are formed into multiple parallel portions, and anti-depression portions are provided between the annular grooves. The anti-depression portions have the same diameter as the fitting surface portions and are in contact with the collector sheet, thereby preventing the collector sheet from sinking into the annular grooves.

[0019] Meanwhile, the exhaust guide portion includes a plurality of tangential grooves formed in parallel with a tangential direction of the support roller, and guides and exhausts the inflowing air along the tangential direction.

[0020] Furthermore, the tangent grooves are spaced apart in the rotation axis and circumferential directions of the support roller, and depression prevention portions are formed between the tangent grooves. The depression prevention portions are in contact with the collector sheet and prevent the collector sheet from sinking into the tangent grooves.

[0021] In addition, as a technical solution to achieve the above-mentioned purpose, the present invention provides another support roller for coating electrode materials with an inflow and exhaust function, which is configured to correspond to the active material coating device for secondary battery production, and supports the collector original sheet during the period when the coating device coats the active material on the collector original sheet. The support roller for coating electrode materials with an inflow and exhaust function includes: a roller core, which has an air guide groove formed on the outer peripheral surface and has a specified diameter; a porous cylinder, which is a cylindrical component with a specified diameter for accommodating the roller core, is bonded to the collector original sheet, and has multiple micropores, which allow the air flowing between the support roller and the collector original sheet to pass through, so as to guide the air to the air guide groove.

[0022] In addition, a plurality of cylinder bonding parts extending along the circumferential direction of the roller core and bonded and fixed to the inner circumferential surface of the porous cylinder are formed on the outer circumference of the roller core. The air guide groove is the space between the cylinder bonding parts, and the micropores are arranged corresponding to the air guide groove.

[0023] Effects of the Invention

[0024] According to the electrode material coating support roller of the present invention having the function of discharging inflowing air as constructed as described above, even if air flows into between the support roller and the collector sheet, the inflowing air will be immediately discharged, thereby preventing the collector sheet from warping relative to the support roller, thereby enabling the coating of a wrinkle-free and uniformly thick electrode material layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a side view showing how an active material is applied to a current collector green sheet using a conventional support roller.

[0026] Figure 2 It is a plan view showing the appearance of an electrode material layer stacked on a current collector sheet.

[0027] Figure 3 Is used to illustrate Figure 1 A diagram showing the problem of the electrode layer coating apparatus.

[0028] Figure 4 It is a front view of the electrode material coating support roller according to the first embodiment of the present invention.

[0029] Figure 5 Is used to illustrate Figure 4 The function of the support roller is shown in the figure.

[0030] Figure 6 This is a front view showing a modified example of the electrode material coating backup roller according to the first embodiment of the present invention.

[0031] Figure 7 This is a front view showing a modified example of the electrode material coating support roller according to the first embodiment of the present invention.

[0032] Figure 8 Is to show the use of Figure 7 Figure 1 shows the appearance of a support roller coated with active material.

[0033] Figure 9 This is a perspective view of a support roller for applying an electrode material according to a second embodiment of the present invention.

[0034] Figure 10 yes Figure 9 Exploded perspective view of the support roller.

[0035] Figure 11 Is used to illustrate Figure 9A side cross-sectional view showing the function of the support roller. DETAILED DESCRIPTION

[0036] An embodiment of the present invention will be described in more detail below with reference to the accompanying drawings.

[0037] Figure 4 1 is a front view of the electrode material coating support roller 30 according to the first embodiment of the present invention. Figure 5 Is used to illustrate Figure 4 The function of the support roller is shown in the figure.

[0038] As shown in the figure, the electrode material coating support roller 30 with an inflow air exhaust function in the first embodiment includes a contact surface 31 and an exhaust guide 33. The support roller 30 has a predetermined diameter and length and is positioned in correspondence with the active material coating device 15. The active material coating device 15 is a slot die used to apply active material to the current collector sheet 11. The support roller 30 rotates parallel to the active material outlet of the active material coating device 15, supporting the current collector sheet 11.

[0039] The current collector sheet 11, supported by a support roller 30, passes through the active material coating apparatus 15. Passing through the active material coating apparatus 15 forms a coated portion and an uncoated portion on the current collector sheet 11. As described above, the coated portion is the portion layered with active material, while the uncoated portion is the portion not layered with active material. As also mentioned above, the active material dries to form a laminate.

[0040] The contact surface portion 31 is a portion having a predetermined diameter that supports the current collector sheet while the coating device 15 is coating the current collector sheet 11 with the active material. The contact surface portion 31 supports the portion to be coated. In other words, the portion supported by the contact surface portion 31 is coated with the active material.

[0041] The exhaust guide 33 supports the portion where the active material is not applied. In other words, the portion supported by the exhaust guide 33 is not coated with the active material. The exhaust guide 33 is located at a position corresponding to the uncoated portion and is integrated with the laminating surface 31 in the center of the support roller 30.

[0042] In addition, the exhaust guide 33 exhausts the air flowing into the space between the support roller and the collector sheet to the outside to prevent the collector sheet from being lifted due to the inflow of air. Figure 1 The air drawn in in the direction of arrow a is immediately discharged to prevent it from being retained between the collector sheet 11 and the support roller 30.

[0043] Figure 5Although the collector sheet 11 is shown as being lifted up from the support roller 30, this is done for convenience in order to indicate the air exhaust path with arrows. As long as the exhaust guide 33 is used, the collector sheet 11 will not be opened from the support roller 30.

[0044] The exhaust guide 33 serves to exhaust air that has flowed between the current collector sheet 11 and the support roller 30 to the outside. "Outside" refers to the space not covered by the current collector sheet 11. By using the exhaust guide 33, air is no longer trapped between the support roller 30 and the current collector sheet 11.

[0045] The exhaust guide 33 includes a plurality of annular grooves 33a and depression prevention portions 33b. The annular grooves 33a have a predetermined width and depth, extend along the circumference of the support roller 30, and guide the incoming air in the circumferential direction, i.e., the direction indicated by arrow c. The annular grooves 33a are annular, encircling the outer circumference of the support roller 30. The plurality of annular grooves 33a are spaced at predetermined intervals.

[0046] The anti-sag portion 33b is formed between the annular grooves 33a and has the same diameter as the contact surface portion 31. It contacts the current collector sheet 11 and prevents the sheet from sinking into the annular grooves 33a. This prevents the sheet 11 from sinking into the annular grooves 33a due to conveying tension. Without the anti-sag portion 33b in the exhaust guide 33, the portion of the current collector sheet 11 that passes through the exhaust guide 33 would sink into the annular grooves 33a due to conveying tension.

[0047] In short, since the exhaust guide portion 33 is provided with a plurality of annular grooves 33 a , the air flowing into the space between the support roller 30 and the current collector sheet 11 is exhausted in the direction of arrow c, thereby preventing the electrode material sheet 11 from warping.

[0048] In this case, the width of the anti-depression portion 33b and the width of the annular groove 33a can be formed to be about 0.5mm to 1.5mm by micro-machining, and the depth of the annular groove 33a can be formed to be about 0.1mm to 0.3mm. In addition, the width of the anti-depression portion 33b and the width of the annular groove 33a can be formed to be substantially the same. For example, if the width of the anti-depression portion 33b is 1mm, the width of the annular groove 33a can also be 1mm. If the width of the anti-depression portion is relatively too large, the amount of the portion of the collector original sheet 11 that passes through the exhaust guide portion 33 and sinks into the annular groove 33a due to the conveying tension will be too small, resulting in a poor anti-warping effect. On the contrary, if the width of the anti-depression portion is too small than the annular groove, the portion of the collector original sheet 11 that passes through the exhaust guide portion 33 will be too much, resulting in a poor anti-wrinkle effect.

[0049] In this case, the annular groove 33a can be formed to gradually widen toward the center of the electrode material coating support roller. Accordingly, while the width of the anti-depression portion 33b and the annular groove 33a are substantially equal on the surface of the electrode material coating support roller, the width of the annular groove 33a widens inward. This throttling effect allows the current collector sheet to fit more closely against the support roller, thereby preventing the electrode material sheet 11 from warping.

[0050] Alternatively, the surface of the electrode material coating support roller may be formed with micro-pits. These micro-pits may be formed by laser etching. The width of these micro-pits may be less than 1㎛. Alternatively, the surface of the electrode material coating support roller may not be completely smooth, but may instead have a surface roughness of approximately 1㎛. Accordingly, these micro-pits and the like can function as air pockets, thereby reducing friction with the current collector sheet 11.

[0051] Figure 6 This is a front view showing a modified example of the electrode material coating backup roller according to the first embodiment of the present invention.

[0052] Figure 6 The support roller 30 shown is a type in which exhaust guides 33 are formed at three locations. Figure 4 The supporting roller 30 is used to support the collector sheet 11 having an uncoated portion formed in the center. Figure 6 The support roller can support the collector sheet with three uncoated sections. Since the exhaust guide 33 corresponds to the position of the uncoated section, the design of the exhaust guide 33 will be different depending on the width or position of the uncoated section in the product being produced.

[0053] Figure 7 1 is a side view showing a modified example of the electrode material coating support roller 30 according to the first embodiment of the present invention. Figure 8 Is to show the use of Figure 7 Figure 1 shows the appearance of a support roller coated with active material.

[0054] Hereinafter, the same reference numerals as those described above denote the same components having the same functions.

[0055] As can be seen from the accompanying drawings, an exhaust guide portion 34 is formed in the longitudinal center of the support roller 30, and a contact surface portion 31 is formed on both sides of the exhaust guide portion 34. Figure 4 The annular exhaust guide 33 described above is the same as that described above. That is, the air flowing between the support roller 30 and the current collector sheet 11 is exhausted while the current collector sheet 11 is supported.

[0056] The exhaust guide 34 corresponds to the uncoated portion of the current collector sheet 11. In other words, it supports the portion of the current collector sheet that is not coated with the active material 12. In contrast, the contact surface 31 corresponds to the coated portion and supports the portion that is coated with the active material.

[0057] The exhaust guide 34 includes a plurality of tangential grooves 34a and a depression prevention portion 34b. The tangential grooves 34a are grooves formed so that their bottom surfaces are parallel to the tangent direction of the outer peripheral surface of the support roller 30. The bottom surfaces of the tangential grooves 34a are spaced apart from the current collector sheet 11, and air can pass between the current collector sheet 11 and the bottom surface.

[0058] The width of each tangential groove 34a is the same as the width of the annular groove 33a. In addition, the plurality of tangential grooves 34a are arranged at intervals along the circumferential direction and the axial direction of the support roller 30.

[0059] The depression prevention portions 34b are curved surfaces between the respective tangent grooves 34a and have the same diameter as the contact surface portion 31 to prevent the current collector sheet 11 from being depressed into the tangent grooves 34a due to conveying tension during conveyance.

[0060] Figure 9 1 is a perspective view of a support roller 50 for coating an electrode material according to a second embodiment of the present invention. Figure 10 yes Figure 9 Exploded perspective view of the support roller. Figure 11 Is used to illustrate Figure 9 A side cross-sectional view showing the function of the support roller.

[0061] As shown in the figure, the electrode material coating support roller 50 of the second embodiment comprises a roller core 51 and a porous cylinder 53. The support roller 50 of the second embodiment also supports the collector sheet 11 while the coating device, i.e., the slot die, is coating the collector sheet with the active material 12.

[0062] The roller core 51 is a roller member with a predetermined diameter, with multiple cylinder-engaging portions 51a and air guide grooves 51b formed on its outer circumference. The cylinder-engaging portions 51a are annular protrusions extending along the circumference of the roller core 51 and are in contact with and fixed to the inner circumference of the porous cylinder 53. As long as the porous cylinder 53 supports the cylinder-engaging portions 51a, the diameter of the porous cylinder 53 does not change (due to external forces).

[0063] The air guide groove 51b is an empty space between the cylinder contact parts 51a. Figure 11 As shown, the air guide groove 51b is a passage that guides the air flowing in through the fine through-hole 53c in the direction of arrow d. The width and depth of the air guide groove 51b can be varied in various ways.

[0064] The porous cylinder 53 is a cylindrical member with a predetermined diameter that houses the roll core 51 within the core housing space 53a. As described above, the inner circumference of the porous cylinder 53 is bonded and fixed to the cylinder bonding portion 51a of the roll core 51. The core housing space 53a houses the roll core 51.

[0065] Furthermore, the porous cylinder 53 is formed with a plurality of fine through-holes 53c. These through-holes 53c have an inner diameter of 1 mm or less and are positioned to correspond to the air guide grooves 51b. Therefore, air flowing through the fine through-holes 53c flows through each of the air guide grooves 51b. Furthermore, air flowing into the air guide grooves 51b passes through the other fine through-holes 53c and is discharged to the outside.

[0066] The portion of the porous cylinder 53 where the fine through-holes 53c are not formed is a contact surface 53b. The contact surface 53b is a curved surface of a predetermined diameter that comes into surface contact with the current collector sheet 11.

[0067] Because the micro-through holes 53c have an inner diameter of less than 1 mm, they can correspond to the entire surface of the current collector sheet 11. This means that they can be formed not only in the uncoated areas of the current collector sheet 11 where the active material 12 will not be applied, but also in the coated areas where the active material will be applied. However, as in the first embodiment, the micro-through holes 53c can also be formed only in the uncoated areas. In other words, the micro-through holes can be formed only in the areas of the current collector sheet 11 where the active material will not be applied.

[0068] Finally, according to the coating support rollers 30 and 50 of the first and second embodiments constructed as described above, when the active material 12 is coated on the collector sheet 11, the air flowing into the space between the collector sheet 11 and the support rollers will be immediately discharged, so that no warping will occur, thereby not only preventing wrinkles but also preventing poor coating.

[0069] The present invention has been described in detail above through specific embodiments, but the present invention is not limited to the above embodiments. Within the scope of the technical concept of the present invention, those skilled in the art can make various modifications thereto.

[0070] Industrial applicability

[0071] The present invention can be used in the secondary battery electrode material coating industry.

Claims

1. A support roller for coating an electrode material with a function of discharging inflow air, which is arranged in correspondence with an active material coating device for manufacturing a secondary battery and supports a collector sheet while the coating device is coating the collector sheet with an active material. The support roller for coating an electrode material with a function of discharging inflow air is characterized by comprising: A fitting surface, which is fitted with the collector original sheet; as well as The exhaust guide portion is integrated with the bonding surface portion and discharges the air flowing into the space between the support roller and the collector original sheet to the outside to prevent the collector original sheet from warping due to the inflow of air.

2. The electrode material coating support roller having an inflow air discharge function according to claim 1, characterized in that: The collector sheet includes a coated portion, which is a region coated with an active material, and an uncoated portion, which is a region not coated with the active material. The exhaust guide portion is located at a position corresponding to the uncoated portion.

3. The electrode material coating support roller having an inflow air discharge function according to claim 1 or 2, characterized in that: The exhaust guide portion includes an annular groove having a predetermined width and depth, extending along the circumferential direction of the support roller, and guiding the inflowing air along the circumferential direction.

4. The electrode material coating support roller having an inflow air discharge function according to claim 3, characterized in that: The annular grooves are formed into a plurality of parallel grooves. An anti-depression portion is provided between the annular grooves. The anti-depression portion has the same diameter as the contact surface portion and contacts the collector original sheet, thereby preventing the collector original sheet from sinking into the annular grooves.

5. The electrode material coating support roller having an inflow air discharge function according to claim 4, characterized in that: The width of the annular groove and the anti-depression portion is 0.5mm to 1.5mm, The depth of the annular groove is 0.1 mm to 0.3 mm.

6. The electrode material coating support roller having an inflow air discharge function according to claim 5, characterized in that: The annular groove has a shape in which the width gradually increases from the surface of the support roller toward the center.

7. The electrode material coating support roller having an inflow air discharge function according to claim 1 or 2, characterized in that: The exhaust guide includes a plurality of tangential grooves formed parallel to a tangential direction of the support roller and configured to guide and exhaust the inflowing air in the tangential direction.

8. The electrode material coating support roller having an inflow air discharge function according to claim 6, characterized in that: The tangential grooves are arranged at intervals in the rotation axis direction and the circumferential direction of the support roller. A depression prevention portion is formed between the cutting grooves. The depression prevention portion contacts the current collector green sheet and prevents the current collector green sheet from sinking into the cutting grooves.

9. A support roller for electrode material coating with a function of exhausting inflow air, arranged in correspondence with an active material coating apparatus for secondary battery production, supporting a current collector sheet while the coating apparatus is coating the current collector sheet with active material, the support roller for electrode material coating with a function of exhausting inflow air being characterized by comprising: a roller core having an air guide groove formed on an outer peripheral surface thereof and having a predetermined diameter; The porous cylinder is a cylindrical member with a predetermined diameter for accommodating the roller core, is attached to the collector sheet, and has a plurality of fine holes for allowing air flowing between the support roller and the collector sheet to pass through the fine holes to guide the air to the air guide grooves.

10. The electrode material coating support roller having an inflow air discharge function according to claim 9, characterized in that: The outer circumferential surface of the roller core is formed with a plurality of cylinder-fitting parts extending along the circumferential direction of the roller core and fixed to the inner circumferential surface of the porous cylinder. The air guide groove is the space between the cylinder-fitting parts. The fine holes are arranged corresponding to the air guide grooves.

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