Gravure roll, coater, pole piece and battery cell

Abstract

The utility model discloses a gravure roll, coating machine, pole piece and electric core, and the gravure roll is used for coating pole piece, comprising: roll body, the peripheral surface of roll body is recessed with ceramic coating area, and the inner edge of at least one side of ceramic coating area is protruded with first protruding portion, in the radial direction of roll body, and first protruding portion is lower than the peripheral surface of roll body. The ceramic coating area on the gravure roll of the utility model is used for coating ceramic layer on the pole piece, and by setting the first protruding portion lower than the surface of the gravure roll on the inner edge of at least one side of the ceramic coating area, the coating amount at the edge position of the coated ceramic layer can be correspondingly reduced, and then the edge position thickness of the ceramic layer of the pole piece is thinner, and if the ceramic slurry of the subsequent pole piece ceramic layer moves and accumulates to the edge, it also will not cause the edge to be too thick, so that when the pole piece passes through the coating die, it will not scratch the coating die and cause the abnormal scraping of the tape, which not only helps to improve the product yield, but also can avoid the shutdown of equipment and improve the production efficiency.

Description

Technical Field

[0001] This utility model relates to the field of lithium battery technology, and in particular to a gravure roller, a coating machine, an electrode sheet, and a battery cell. Background Technology

[0002] Lithium-ion batteries possess outstanding advantages such as high voltage, high capacity, small size, light weight, environmental friendliness, and long lifespan, and are widely used in various portable electronic products. To effectively reduce costs and improve battery performance, lithium-ion batteries with centrally located tabs have been developed. In the production process of these batteries, the electrode coating process is crucial. The intermittent coating method using active coatings not only precisely reserves the tab welding area but also allows for the application of ceramic coatings in the intermittent areas, providing insulation and protection, thereby ensuring the battery's safety and stability.

[0003] However, in existing gravure rollers, ceramic slurry is coated onto the electrode to form a ceramic layer. Because the solvent evaporates faster at the edges of the ceramic layer than in the center, the solid content of the slurry at the edges increases rapidly, resulting in a much higher surface tension at the edges compared to the center. This difference in surface tension between the edges and the center generates a driving force that causes the liquid inside the electrode to move towards the edges. During the subsequent drying process, the edge area accumulates more slurry, eventually forming a thick edge.

[0004] When the electrode passes through the coating die, the protruding thick ceramic edge is very easy to rub against the die. This not only damages the integrity of the electrode surface, causing abnormal scraping and defects such as breakage and scratches, but also seriously affects the quality and performance of the electrode. It may also cause production equipment failure, increase equipment maintenance costs, reduce production efficiency, and thus affect the normal operation of the entire battery production line. Utility Model Content

[0005] The main purpose of this invention is to propose a gravure roller, which aims to solve the technical problem in the prior art that the ceramic coating edge of the electrode sheet is too thick, causing it to rub against the coating die head.

[0006] To achieve the above objectives, this utility model proposes a gravure roller for coating electrode sheets, the gravure roller comprising:

[0007] The roller body has a ceramic coating area recessed on its peripheral side, and a first protrusion protrudes from the inner edge of at least one side of the ceramic coating area. In the radial direction of the roller body, the first protrusion is lower than the peripheral side of the roller body.

[0008] In some embodiments, the first protrusion is provided on the inner edge of each side of the ceramic coating area.

[0009] In some embodiments, the width of the first protrusion is 2mm to 10mm; and / or,

[0010] The height of the first protrusion is 20μm to 100μm.

[0011] In some embodiments, the gravure roller further includes:

[0012] Multiple engraving sections are located in the ceramic coating area and are used to engrave tab grooves on the electrode sheet;

[0013] The ceramic coating area has a second protrusion on the outer edge of at least one side of the engraving part, and the second protrusion is lower than the engraving end face of the engraving part in the radial direction of the roller.

[0014] In some embodiments, the ceramic coating area has a second protrusion on each side of the outer edge of the engraved portion.

[0015] In some embodiments, the width of the second protrusion is 2mm to 10mm; and / or,

[0016] The height of the second protrusion is 20μm to 100μm.

[0017] In some embodiments, the recess depth of the ceramic coating area is 145 μm to 155 μm.

[0018] The second aspect of this utility model provides a coating machine, including the gravure roller as described above.

[0019] The third aspect of this utility model provides an electrode sheet manufactured using the coating machine described above, the electrode sheet comprising:

[0020] current collector;

[0021] An active material layer and a ceramic layer are alternately disposed on the current collector along the length direction of the current collector, and the ceramic layer is formed by coating the ceramic coating area of ​​the gravure roller.

[0022] The fourth aspect of this utility model provides a battery cell, including a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet, the separator, and the negative electrode sheet are stacked and wound together to form a wound core;

[0023] Wherein, at least one of the positive electrode and the negative electrode adopts the electrode as described above.

[0024] The ceramic coating area on the gravure roller of this invention is used to coat a ceramic layer on the electrode. By setting a first protrusion lower than the surface of the gravure roller at at least one inner edge of the ceramic coating area, the coating amount at the edge of the coated ceramic layer can be reduced accordingly, thereby making the edge thickness of the electrode ceramic layer thinner. If the ceramic slurry of the electrode ceramic layer moves and accumulates towards the edge, it will not cause the edge to be too thick. Thus, when the electrode passes through the coating die, it will not rub against the coating die and cause abnormal scraping. This not only helps to improve product yield, but also avoids equipment downtime and improves production efficiency. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the structure of an embodiment of the gravure roller of this utility model;

[0026] Figure 2 This is a schematic diagram of the structure of an embodiment of the gravure roller of this utility model;

[0027] Figure 3 This is a schematic diagram of the structure of an embodiment of the gravure roller of this utility model;

[0028] Figure 4 This is a schematic diagram of the structure of an embodiment of the electrode sheet of this utility model.

[0029] Explanation of icon numbers:

[0030] label name label name 100 Gravure roller 110 Roller body 120 Ceramic coating area 130 Sculpture Department 121 First protrusion 122 Second protrusion 200 Polaroid 213 Ear groove 210 current collector 211 Active material layer 212 ceramic layer Detailed Implementation

[0031] The solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0032] It should be noted that all directional indicators (such as up, down, left, right, front, back, etc.) in this utility model embodiment are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicator will also change accordingly.

[0033] It should also be noted that when a component is described as "fixed to" or "set on" another component, it can be directly on the other component or there may be an intervening component present. When a component is described as "connected to" another component, it can be directly connected to the other component or there may be an intervening component present.

[0034] Furthermore, the use of terms such as "first" and "second" in this utility model is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this utility model.

[0035] Please refer to Figures 1 to 3 This utility model provides a gravure roller 100 for coating electrode sheets 200, comprising:

[0036] The roller body 110 has a ceramic coating area 120 recessed on its peripheral side surface. At least one inner edge of the ceramic coating area 120 has a first protrusion 121 protruding. In the radial direction of the roller body 110, the first protrusion 121 is lower than the peripheral side surface of the roller body 110.

[0037] The roller 110 is mounted on the coating machine and is used to contact the electrode 200 to coat the electrode 200 with ceramic slurry to form a ceramic layer 212.

[0038] The main function of the ceramic coating area 120 is to coat the electrode 200 with ceramic slurry to form a ceramic layer 212. The ceramic coating area 120 is recessed relative to the peripheral side of the gravure roller 100, which can fill the ceramic slurry in the ceramic coating area 120 to coat the electrode 200.

[0039] After the ceramic slurry is coated on the electrode 200, the solvent evaporates faster at the edges than in the center, causing a rapid increase in the solid content of the slurry at the edges. This results in a much higher surface tension at the edges compared to the center. This difference in surface tension between the edges and the center generates a driving force that causes the liquid inside the electrode 200 to move towards the edges, leading to an increase in the ceramic slurry content and a thicker electrode at the edges.

[0040] The ceramic coating area 120 is rectangular in shape, adapted to the electrode 200, and can coat the electrode 200 to form a rectangular ceramic layer 212, which more comprehensively covers the current collector 210 and provides insulation protection. Of course, the above is only an example, and the specific shape can be determined according to actual needs. This utility model does not limit it.

[0041] Therefore, a first protrusion 121 is provided on the inner edge of at least one side of the ceramic coating area 120, and the first protrusion 121 is lower than the peripheral surface of the roller body 110. The first protrusion 121 and the peripheral surface of the roller body 110 form a stepped structure, and the first protrusion 121 corresponds to the edge position of the electrode 200 during coating. Since the first protrusion 121 protrudes relative to the ceramic coating area 120, the content of ceramic slurry at the position of the first protrusion 121 is relatively small. Therefore, after actual coating, the content of ceramic slurry at at least one edge is less than the content in the middle of the ceramic layer 212 of the electrode 200, and even if some of the ceramic slurry in the middle moves to the edge, it will not cause excessive thickness.

[0042] The ceramic coating area 120 may have a first protrusion 121 protruding from at least one inner edge along the axial direction of the roller body 110, or from at least one inner edge along the radial direction of the roller body 110, or from the inner edges of opposite sides along the axial direction of the roller body 110, etc. Of course, the above are merely examples; the specific design location can be determined according to actual needs, and this utility model does not impose any limitations.

[0043] The gravure roller 100 of this invention features a recessed ceramic coating area 120, with at least one inner edge of the ceramic coating area 120 having a first protrusion 121 lower than the circumferential side of the roller body 110. At the start of coating, the amount of ceramic slurry filling the first protrusion 121 is relatively small. After coating the electrode 200, the first protrusion 121 has less ceramic slurry coating at the edge of the electrode 200, resulting in a thinner edge thickness for the ceramic layer 212 of the electrode 200. If the ceramic slurry in the ceramic layer 212 of the electrode 200 subsequently moves towards the edge under surface tension, it will not lead to excessively high edge content, preventing the formation of thick edges during subsequent drying. This reduces the scraping abnormality caused by the thick edge of the ceramic layer 212 rubbing against the coating die, improving product yield. Furthermore, it reduces equipment failure rate, decreases equipment downtime for maintenance, improves production line operating efficiency, ensures production continuity, and ultimately reduces production costs.

[0044] In this embodiment, please refer to Figures 1 to 3 Each side of the ceramic coating area 120 has a first protrusion 121 protruding from its inner edge.

[0045] When the first protrusion 121 is located on the inner edge of each side of the ceramic coating area 120, the filling amount at each inner edge will be reduced when the ceramic slurry is filled by the gravure roller 100. During coating, the amount of ceramic slurry coated at the edge of the electrode 200 will be reduced. Even if the rapid evaporation of solvent at the edge causes a change in surface tension, prompting the slurry to migrate towards the edge, it will not result in excessive ceramic slurry at the edge, forming a thick edge. Compared to setting the first protrusion 121 on one side or opposite sides, setting it on all edges can more comprehensively and effectively control the amount of ceramic slurry coated, greatly improving the coating effect of the ceramic coating on the entire surface of the electrode 200, providing a more reliable guarantee for the safety and stability of the battery, and also reducing friction between the electrode 200 and the coating die, thus improving product yield.

[0046] In some embodiments, the width of the first protrusion 121 is 2 mm to 10 mm.

[0047] In other words, the width of the first protrusion 121 can be 2mm, 6mm, or 10mm, etc. When the width of the first protrusion 121 is 2mm, the narrower first protrusion 121 occupies less space in the ceramic coating area 120, allowing the roller 110 to carry more slurry for coating the main body area in a single rotation, thus meeting the thickness requirements of the ceramic coating on the main body of the electrode 200. At the same time, it can also form a smaller ceramic thinning section at the edge of the electrode 200, avoiding excessively thick edges.

[0048] When the width of the first protrusion 121 is 6mm, the 6mm wide first protrusion 121 has better versatility, can adapt to various slurry characteristics, ensure the stability of the coating effect, and can further improve the thinning effect of the ceramic layer 212 at the edge of the electrode 200.

[0049] When the width of the first protrusion 121 is 10mm, during coating, the ceramic layer 212 at the edge of the electrode 200 is thinned to a wider section. When the ceramic slurry in the middle migrates to the edge, the probability of thick edges is greatly reduced, and the content of ceramic slurry in the middle can be guaranteed to meet the standard, thus achieving the effect of insulation protection.

[0050] In this embodiment, the width of the first protrusion 121 is 3mm. After the electrode 200 is coated, the edge of the electrode 200 also has a ceramic coating of approximately 3mm. The ceramic coating in the center of the electrode 200 accumulates towards the edge in a small portion without becoming too thick. Of course, the above is only an example, and the specific width can be determined according to actual needs. This utility model does not impose any limitations on this.

[0051] In some embodiments, the height of the first protrusion 121 is 20 μm to 100 μm. Specifically, the height of the first protrusion 121 can be 20 μm, 60 μm, or 100 μm, etc.

[0052] When the height of the first protrusion 121 is 20μm, during the coating operation on the gravure roller 100, the amount of paste filling in the edge area is appropriately reduced to avoid forming a thick edge due to excessive filling during drying.

[0053] When the height of the first protrusion 121 is 60 μm, the first protrusion 121 of this height can more effectively limit the amount of ceramic paste filling at the edge of the gravure roller 100, thereby reducing the amount of ceramic coating at the edge of the electrode 200. By significantly reducing the accumulation of paste at the edge, the generation of thick edge phenomenon is effectively suppressed.

[0054] When the height of the first protrusion 121 is 100μm, its effect on reducing the amount of ceramic slurry filling is extremely significant, greatly avoiding the phenomenon of thick ceramic edges. Furthermore, due to its height advantage, the 100μm high first protrusion 121 is better able to resist slurry erosion and wear during long-term coating operations, exhibiting higher mechanical stability, reducing the frequency of equipment maintenance and replacement, helping to lower production costs, and ensuring the continuity and stability of high-end product production.

[0055] In this embodiment, the height of the first protrusion 121 is 45 μm. After coating, there is a difference in coating thickness between the center and the edge of the electrode 200, forming a gradient coating structure. Even if some slurry shifts to the edge before drying, it will not cause the edge to be too thick and scratch the die head. In addition, during actual coating, because some slurry adheres to the gravure roller 100, the coating thickness on the edge of the electrode 200 is less than 105 μm, but it can still improve the safety of the battery in the subsequent nail penetration test to a certain extent. Of course, the above is only an example, and the specific engraving depth can be determined according to actual needs. This utility model does not limit this.

[0056] In this embodiment, to avoid applying ceramic slurry to the tab welding position of the electrode sheet 200, the tab welding is completed more quickly, improving production efficiency. Please refer to... Figures 1 to 3 The gravure roller 100 also includes a plurality of engraving sections 130 located in the ceramic coating area 120 and used to engrave tab grooves 213 on the electrode sheet 200. In order to avoid the formation of thick ceramic edges at the edges of the tab grooves 213, the ceramic coating area 120 has a second protrusion 122 protruding from at least one outer edge of the engraving section 130. In the radial direction of the roller body 110, the second protrusion 122 is lower than the engraving end face of the engraving section 130.

[0057] In the axial direction of the gravure roller 100, the ceramic coating area 120 is provided with four engraving sections 130, each with a length and width of 5cm. During coating, since the engraving sections 130 are not filled with ceramic slurry, the tab grooves 213 can be engraved on the ceramic part of the electrode sheet 200, eliminating the need to spend more time cleaning the slurry at the tab welding position, thus improving efficiency.

[0058] Please continue to refer to this. Figure 2 and Figure 3 The ceramic coating area 120 has a second protrusion 122 protruding from at least one outer edge of the engraving section 130. That is, the ceramic coating area 120 may have the second protrusion 122 protruding from at least one outer edge of the engraving section 130 along the axial direction of the roller body 110, or along the radial direction of the roller body 110, or along opposite outer edges of the engraving section 130, etc. Of course, the above are merely examples; the specific design location can be determined according to actual needs, and this utility model does not impose any limitations here.

[0059] Please refer to Figure 1 In this embodiment, the ceramic coating area 120 has a second protrusion 122 protruding from each side of the outer edge of the engraving part 130.

[0060] When the second protrusion 122 is provided on the outer edges of each side of the engraving section 130, the filling amount of ceramic slurry on each side of the engraving section 130 will be reduced when the gravure roller 100 fills the ceramic slurry. During electrode coating, the amount of ceramic slurry coated at the edge of the tab groove 213 will be reduced. Even if the rapid evaporation of solvent at the edge causes a change in surface tension, prompting the slurry to migrate towards the edge of the tab groove 213, it will not result in excessive ceramic slurry at the edge of the tab groove 213, thus preventing the formation of a thick edge. Compared to providing the second protrusion 122 on one side or opposite sides, providing it on all outer edges allows for more comprehensive and effective control of the ceramic slurry coating amount, providing a more reliable guarantee for the safety and stability of the battery. It also reduces friction between the electrode 200 and the coating die, improving product yield.

[0061] In some embodiments, the width of the second protrusion 122 is 2mm to 10mm. Specifically, the width of the second protrusion 122 can be 2mm, 6mm, or 10mm, etc.

[0062] When the width of the second protrusion 122 is 2mm, the narrower second protrusion 122 occupies less space in the ceramic coating area 120, allowing the roller 110 to carry more slurry for coating the main body area in a single rotation, thus meeting the thickness requirements of the ceramic coating on the main body of the electrode 200. Simultaneously, it also forms a smaller ceramic thinning section at the edge of the tab groove 213, preventing excessively thick edges.

[0063] When the width of the second protrusion 122 is 6mm, the 6mm wide second protrusion 122 has better versatility, can adapt to various slurry characteristics, ensure the stability of the coating effect, and can further improve the thinning effect of the ceramic layer 212 at the edge of the tab groove 213.

[0064] When the width of the second protrusion 122 is 10mm, during coating, the ceramic layer 212 at the edge of the tab groove 213 is thinned to a wider section. When the ceramic slurry in the middle migrates to the edge of the tab groove 213, the probability of thick edges is greatly reduced, and the content of ceramic slurry in the middle can be guaranteed to meet the standard, thus achieving the effect of insulation protection.

[0065] In this embodiment, the width of the second protrusion 122 is 3mm. After the electrode 200 is coated, the edge of the electrode groove 213 also has a ceramic coating of approximately 3mm. The ceramic coating at the center of the electrode 200 accumulates towards the edge of the electrode groove 213 without becoming too thick. Of course, the above is only an example, and the specific width can be determined according to actual needs. This utility model does not impose any limitations on this.

[0066] In some embodiments, the height of the second protrusion 122 is 20 μm to 100 μm. Specifically, the height of the second protrusion 122 can be 20 μm, 60 μm, or 100 μm, etc.

[0067] When the height of the second protrusion 122 is 20μm, during the coating operation on the gravure roller 100, the amount of slurry filling in the edge area of ​​the tab groove 213 is appropriately reduced to avoid forming a thick edge due to excessive filling during drying.

[0068] When the height of the second protrusion 122 is 60μm, the second protrusion 122 of this height can more effectively limit the amount of ceramic slurry filling at the edge of the engraved portion 130, thereby reducing the amount of ceramic coating at the edge of the tab groove 213. By significantly reducing the accumulation of slurry at the edge of the tab groove 213, the generation of thick edge phenomenon is effectively suppressed.

[0069] When the height of the second protrusion 122 is 100μm, its effect on reducing the amount of ceramic slurry filling is extremely significant, greatly avoiding the phenomenon of thick ceramic edges at the edge of the tab groove 213. Furthermore, due to its height advantage, the 100μm high second protrusion 122 is better able to resist slurry erosion and wear during long-term coating operations, exhibiting higher mechanical stability, reducing the frequency of equipment maintenance and replacement, helping to lower production costs, and ensuring the continuity and stability of high-end product production.

[0070] In this embodiment, the height of the second protrusion 122 is 45 μm. After coating, there is a difference in coating thickness between the center of the electrode 200 and the edge of the tab groove 213, forming a gradient coating structure. Even if some slurry shifts to the edge of the tab groove 213 before drying, it will not cause the edge to be too thick and scratch the die head. In addition, during actual coating, because some slurry adheres to the gravure roller 100, the amount coated on the edge of the tab groove 213 will be less, but it can still improve the safety of the battery in the subsequent nail penetration test to a certain extent. Of course, the above is only an example, and the specific engraving depth can be determined according to actual needs. This utility model does not limit it here.

[0071] In some embodiments, the recess depth of the ceramic coating area 120 is 145 μm to 155 μm.

[0072] In other words, the recess depth of the ceramic coating area 120 can be 145μm, 150μm, or 155μm, etc. When the recess depth is 145μm, the amount of ceramic slurry carried by the gravure roller 100 in a single operation is relatively small, and the initial distribution of the slurry on the electrode 200 is thinner. This helps to reduce the initial thickness of the slurry edge, thereby reducing the formation of thick edges while ensuring that the ceramic layer 212 can still perform its insulating function.

[0073] When the recess depth is 155μm, the gravure roller 100 can carry more ceramic slurry, enhancing the insulation performance and improving the wear resistance of the electrode 200. Of course, the above is just an example, and the specific recess depth can be determined according to actual needs. This utility model does not impose any limitations on this.

[0074] In this embodiment, when the recess depth of the ceramic coating area 120 is 150μm, the amount of slurry carried by the gravure roller 100 can further optimize the insulation and protection properties of the coating, and will not cause obvious edge thickening problems due to excessive slurry.

[0075] The second aspect of this utility model provides a coating machine, including the gravure roller 100 as described above, for manufacturing electrode sheets 200.

[0076] Since the coating machine adopts all the technical solutions of all the embodiments of the above-mentioned gravure roller 100, the coating machine of this utility model also has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be described in detail here.

[0077] The third aspect of this utility model discloses an electrode sheet 200, manufactured using the coating machine described above. Please refer to [reference needed]. Figure 4 The electrode 200 includes a current collector 210, an active material layer 211, and a ceramic layer 212. The active material layer 211 and the ceramic layer 212 are alternately disposed on the current collector 210 along the length direction of the current collector 210. The ceramic layer 212 is formed by coating the ceramic coating area 120 of the gravure roller 100.

[0078] The fourth aspect of this utility model provides a battery cell, including a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet, the separator, and the negative electrode sheet are stacked and wound together to form a wound core.

[0079] Among them, at least one of the positive electrode and the negative electrode adopts the electrode 200 described above.

[0080] The above are only some or preferred embodiments of this utility model. Neither the text nor the drawings should limit the scope of protection of this utility model. All equivalent structural transformations made using the contents of this utility model specification and drawings under the overall concept of this utility model, or direct / indirect applications in other related technical fields, are included within the scope of protection of this utility model.

Claims

1. A gravure roller for coating electrode sheets, characterized in that, The gravure roller includes: The roller body has a ceramic coating area recessed on its peripheral side, and a first protrusion protrudes from the inner edge of at least one side of the ceramic coating area. In the radial direction of the roller body, the first protrusion is lower than the peripheral side of the roller body.

2. The gravure roller according to claim 1, characterized in that, The inner edge of each side of the ceramic coating area is provided with the first protrusion.

3. The gravure roller according to claim 1, characterized in that, The width of the first protrusion is 2mm to 10mm; and / or, The height of the first protrusion is 20μm to 100μm.

4. The gravure roller according to claim 1, characterized in that, The gravure roller also includes: Multiple engraving sections are located in the ceramic coating area and are used to engrave tab grooves on the electrode sheet; The ceramic coating area has a second protrusion on the outer edge of at least one side of the engraving part, and the second protrusion is lower than the engraving end face of the engraving part in the radial direction of the roller.

5. The gravure roller according to claim 4, characterized in that, The ceramic coating area has a second protrusion on each side of the outer edge of the engraved part.

6. The gravure roller according to claim 4, characterized in that, The width of the second protrusion is 2mm to 10mm; and / or, The height of the second protrusion is 20μm to 100μm.

7. The gravure roller according to any one of claims 1 to 6, characterized in that, The depth of the depression in the ceramic coating area is 145μm to 155μm.

8. A coating machine, characterized in that, Includes the gravure roller as described in any one of claims 1 to 7.

9. An electrode sheet, characterized in that, The electrode sheet is manufactured using the coating machine as described in claim 8, and comprises: current collector; An active material layer and a ceramic layer are alternately disposed on the current collector along the length direction of the current collector, and the ceramic layer is formed by coating the ceramic coating area of ​​the gravure roller.

10. A battery cell, characterized in that, It includes a positive electrode sheet, a negative electrode sheet, and a separator, wherein the positive electrode sheet, the separator, and the negative electrode sheet are stacked on top of each other and wound together to form a core; Wherein, at least one of the positive electrode and the negative electrode adopts the electrode as described in claim 9.

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