Rolling device and battery manufacturing equipment

Abstract

The utility model discloses a rolling device and battery manufacturing equipment, the rolling device is used for rolling a pole piece, and the pole piece comprises a film coating area and a pole lug. The rolling device comprises a pair of rollers. A plurality of annular grooves which are distributed at intervals in the axial direction of each roller are formed in the roller surface of each roller, each annular groove is formed around the central axis of the corresponding roller, and a rolling section is formed between every two adjacent annular grooves. Wherein the diameter of the rolling section is gradually reduced from the middle of the rolling section to the two ends of the rolling section in the axial direction of the roller. The rolling device can improve the quality of the pole piece and improve the reliability of the battery monomer.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a rolling device and battery manufacturing equipment. Background Art

[0002] With the development of new energy technology, batteries are being used more and more widely. Batteries have high energy density, high safety, long service life, and are green and environmentally friendly to the social environment. They have been widely used in passenger cars, commercial vehicles, electric bicycles, heavy trucks, energy storage facilities, battery swap stations, engineering manufacturing, smart equipment, etc. At the same time, they also promote technical development and research in communications, medical equipment, energy development, etc.

[0003] In battery technology, the pole piece is one of the core components of the battery cell. The quality of the pole piece has an important impact on the reliability of the battery cell. How to improve the quality of the pole piece and improve the reliability of the battery cell is a technical problem that needs to be solved urgently. Utility Model Content

[0004] The embodiments of the present application provide a rolling device and a battery manufacturing device, which can effectively improve the quality of pole pieces and the reliability of battery cells.

[0005] In a first aspect, an embodiment of the present application provides a rolling device for rolling a pole piece, wherein the pole piece includes a coating area and a pole ear, and the rolling device includes a pair of rollers;

[0006] The roller surface of each roller is provided with a plurality of annular grooves spaced apart along the axial direction thereof, each of the annular grooves is arranged around the central axis of the roller, and a rolling section is formed between two adjacent annular grooves;

[0007] Wherein, along the axial direction of the rolling roller, from the middle to both ends of the rolling section, the diameter of the rolling section gradually decreases.

[0008] In the above technical solution, the rolling section is used to roll the main body of the coating area, and the annular groove corresponds to the edge of the coating area. The annular groove can reduce the rolling force on the edge of the coating area, reduce the thickness difference between the main body of the coating area and the edge of the coating area, and improve the thickness consistency of the coating area. Along the axial direction of the roller, the diameter of the rolling section gradually decreases from the middle to the two ends of the rolling section. In this way, the two ends of the rolling section are smaller, and along the radial direction of the roller, the steps formed at the connection positions of the two ends of the rolling section and the annular groove are lower, which can alleviate the stress concentration at the connection positions of the main body of the coating area and the edge of the coating area, reduce the risk of cracking or falling off of the coating area, improve the quality of the pole piece, and improve the reliability of the battery cell.

[0009] In some embodiments, the rolling section is a rotating body, and the generatrix of the outer peripheral surface of the rolling section is an arc line.

[0010] In the above technical solution, the generatrix of the outer peripheral surface of the rolling section is an arc line, which can further alleviate the stress concentration of the main body of the coating area and reduce the risk of cracking or falling off of the main body of the coating area.

[0011] In some embodiments, along the axial direction of the roller, the diameters of both ends of the rolling section are equal.

[0012] In the above technical solution, the two ends of the rolling section are of the same size, which can improve the consistency of the rolls and reduce the difficulty of roll preparation.

[0013] In some embodiments, the difference between the maximum diameter of the rolling section and the minimum diameter of the rolling section is Δφ, which satisfies 0um<Δφ≤40um.

[0014] In the above technical solution, the difference between the maximum diameter of the rolling section and the minimum diameter of the rolling section is small, and the bulging degree in the middle of the rolling section along the radial direction of the roller is low, which can reduce the impact on the consistency of the main thickness of the coating area.

[0015] In some embodiments, 4um≤Δφ≤30um.

[0016] In the above technical solution, 4um≤△φ, the bulging degree in the middle of the rolling section will not be too low, and the step formed at the connection position of the rolling section and the annular groove is low, which can alleviate the stress concentration at the connection position of the main body of the coating area and the edge of the coating area; △φ≤30um, the bulging degree in the middle of the rolling section will not be too large, and the bulging degree in the middle of the rolling section will not be too high, which can further reduce the impact of the rolling section on the thickness consistency of the main body of the coating area. Therefore, 4um≤△φ≤30um can alleviate the stress concentration at the connection position of the main body of the coating area and the edge of the coating area, and improve the thickness consistency of the coating area.

[0017] In some embodiments, the annular groove includes a groove bottom surface and a groove side surface connected to the groove bottom surface, and the outer peripheral surface of the rolling segment is connected to the groove side surface.

[0018] In the above technical solution, a step is formed at the position where the groove side surface connects with the surface of the rolling section, which can alleviate the rolling force on the edge of the coating area to a large extent.

[0019] In some embodiments, along the radial direction of the rolling roller, the height difference between the end of the rolling section and the bottom surface of the groove is △H, satisfying 0um<△H≤20um.

[0020] In the above technical solution, 0um<△H, there is a height difference between the end of the rolling section and the bottom surface of the groove, which can alleviate the rolling force on the edge of the coating area, reduce the thickness difference between the main body of the coating area and the edge of the coating area, and improve the thickness consistency of the coating area; △H≤20um, the height difference between the end of the rolling section and the bottom surface of the groove will not be too large, so that the bottom surface of the groove can roll the edge of the coating area and improve the compaction density of the edge of the coating area. Therefore, 0um<△H≤20um can take into account both the thickness consistency and the compaction density of the coating area.

[0021] In some embodiments, 10um≤ΔH≤20um.

[0022] In the above technical solution, the thickness consistency of the coating area and the compaction density of the coating area can be further taken into consideration.

[0023] In some embodiments, the rolled section transitions to the groove side in a circular arc.

[0024] In the above technical solution, the arc transition between the rolling section and the groove side surface can further alleviate the stress concentration at the connection position between the edge of the coating area and the main body of the coating area.

[0025] In some embodiments, along the axial direction of the roller, the plurality of annular grooves include two first annular grooves located at both ends and at least one second annular groove located between the two first annular grooves, and the groove depth of the second annular groove is smaller than the groove depth of the first annular groove.

[0026] In the above technical solution, the groove depth of the second annular groove is smaller than the groove depth of the first annular groove, and the rolling force applied to the coating area corresponding to the second annular groove is smaller than the rolling force applied to the coating area corresponding to the first annular groove, thereby alleviating the influence of the roller deflection deformation on the thickness consistency of the coating area.

[0027] In a second aspect, an embodiment of the present application further provides a battery manufacturing device, the battery manufacturing device comprising the above-mentioned rolling device. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0029] Figure 1 A schematic diagram of the structure of a rolling device in some embodiments of the present application;

[0030] Figure 2 A schematic structural diagram of a roller from one perspective of some embodiments of the present application;

[0031] Figure 3 A schematic diagram of the structure of a roller in some embodiments of the present application;

[0032] Figure 4 This is a schematic diagram of the structure of the pole piece of some embodiments of the present application;

[0033] Figure 5 This is a schematic diagram of the structure of the sub-pole piece of some embodiments of the present application;

[0034] Figure 6 for Figure 5 Section view along AA;

[0035] Figure 7 Schematic diagram of the structure of rollers in other embodiments of the present application.

[0036] Icon; 200-pole piece; 201-sub-pole piece; 21-coating area; 211-edge of coating area; 212-body of coating area; 22-pole ear; 100-rolling device; 10-roller; 11-annular groove; 11a-first annular groove; 11b-second annular groove; 111-bottom surface of groove; 112-side surface of groove; 12-rolling section; P-axial direction; Z-thickness direction; Y-length direction; X-width direction.

[0037] The drawings are not drawn to scale. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as those commonly understood by technicians in the technical field of this application; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned drawings and any variations thereof are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship.

[0040] Reference to "embodiment" in this application means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments.

[0041] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "attached" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0042] In the description of the present application, it should be noted that, unless otherwise specified, "multiple" means more than two; the terms "upper", "lower", "left", "right", "inside", "outside", etc., indicating the orientation or positional relationship, are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. "Vertical" is not strictly vertical, but is within the allowable error range. "Parallel" is not strictly parallel, but is within the allowable error range.

[0043] The term "and / or" in this application is only a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0044] In the embodiments of the present application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components are omitted in different embodiments. It should be understood that the thickness, length, width and other dimensions of various components in the embodiments of the present application shown in the drawings, as well as the overall thickness, length, width and other dimensions of the integrated device are only exemplary descriptions and should not constitute any limitation to the present application.

[0045] The term "plurality" used in the present application refers to two or more (including two).

[0046] In the present application, battery cells may include but are not limited to lithium-ion secondary batteries, lithium-ion primary batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries or magnesium-ion batteries, etc. Battery cells include but are not limited to cylinders, flat bodies, rectangular parallelepipeds or other shapes, etc. Battery cells generally include cylindrical battery cells, square battery cells and soft-pack battery cells, etc., according to the packaging method.

[0047] A battery cell includes an electrode assembly and an electrolyte. The electrode assembly is composed of a positive electrode sheet, a negative electrode sheet, and a separator. A battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to work. Metal ions (such as lithium ions) are embedded and removed between the positive electrode and the negative electrode. The separator is set between the positive electrode and the negative electrode to prevent the positive electrode sheet and the negative electrode sheet from short-circuiting, while allowing active ions to pass through.

[0048] The battery mentioned in the embodiments of the present application refers to a single physical module including one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in the present application may include a battery module or a battery pack.

[0049] The development of battery technology must take into account many design factors at the same time, such as energy density, cycle life, discharge capacity, charge and discharge rate and other performance parameters. In addition, battery reliability must also be considered.

[0050] The preparation of the pole piece usually involves coating the surface of the current collector with slurry to form the pole piece. After the slurry dries, a coating area is formed, which can be understood as the active material layer area. Due to the fluidity of the slurry, after the slurry is coated on the current collector and dried, the coating area will be thin at the edge (also known as the thinning area) and thick in the middle, that is, there is a thickness difference between the main body of the coating area and the edge.

[0051] The thickness consistency of the coating area has an important impact on the performance of battery cells. In the battery production process, rolling pole pieces are usually used to increase the compaction density of the pole pieces and thus increase the energy density of the battery cells. During the rolling process of the pole pieces, the two rollers will undergo deflection deformation (the ends of the two rollers are close, and the middle of the two rollers are far away), resulting in a decrease in the rolling force of the rollers on the main body of the coating area, and an increase in the rolling force of the rollers on the edge of the coating area, resulting in an increase in the thickness difference between the edge and the middle of the coating area. This type of pole piece is used for battery cells. The gap corresponding to the edges of the coating areas of two adjacent pole pieces is large, the ion transmission distance is long, the insufficient power performance of the battery cell causes lithium precipitation, and the reliability of the battery cell is reduced.

[0052] In order to alleviate the influence of roller deflection on the thickness of the coating area, a groove can be set on the roller surface corresponding to the edge of the coating area. However, setting the groove will cause a step at the position where the groove connects with the roller surface, causing stress concentration, resulting in cracking or falling off of the coating area, and affecting the quality of the pole piece.

[0053] In view of this, in order to solve the problem of roller stress concentration, resulting in cracking or shedding of the coating area, affecting the quality of the pole piece, and reducing the reliability of the battery cell, the embodiment of the present application provides a rolling device, which includes a pair of rollers, and the roller surface of each roller is provided with a plurality of annular grooves arranged along its axial direction, each annular groove is arranged around the central axis of the roller, and a rolling section is formed between two adjacent annular grooves. Among them, along the axial direction of the roller, from the middle to the two ends of the rolling section, the diameter of the rolling section gradually decreases.

[0054] The rolling section is used to roll the main body of the coating area, and the annular groove corresponds to the edge of the coating area. The annular groove can reduce the rolling force on the edge of the coating area, reduce the thickness difference between the main body of the coating area and the edge of the coating area, and improve the thickness consistency of the coating area.

[0055] Along the axial direction of the roller, the diameter of the rolling section gradually decreases from the middle to the two ends of the rolling section. In this way, the two ends of the rolling section are smaller, and along the radial direction of the roller, the steps formed by the connection positions of the two ends of the rolling section and the annular groove are lower, which can alleviate the stress concentration on the connection position between the main body of the coating area and the edge of the coating area, reduce the risk of cracking or falling off of the coating area, improve the quality of the pole piece, and improve the reliability of the battery cell.

[0056] The technical solution disclosed in the embodiments of the present application is applicable to the preparation of pole pieces and other sheets.

[0057] The embodiment of the present application provides a rolling device 100, which can improve the quality of the pole piece 200 and improve the reliability of the battery cell. The specific structure of the rolling device 100 is described in detail below with reference to the accompanying drawings.

[0058] Figure 1 It is a structural schematic diagram of a rolling device 100 of some embodiments of the present application; Figure 2 A schematic structural diagram of a roller 10 from one perspective of some embodiments of the present application; Figure 3 It is a schematic structural diagram of a roller 10 in some embodiments of the present application; Figure 4 It is a schematic diagram of the structure of the pole piece 200 of some embodiments of the present application; Figure 5 A schematic diagram of the structure of the sub-pole piece 201 of some embodiments of the present application; Figure 6 for Figure 5 Section view along AA.

[0059] Reference Figures 1 to 6 The embodiment of the present application provides a rolling device 100 , which is used to roll a pole piece 200 . The pole piece 200 includes a coating area 21 and a pole ear 22 .

[0060] The rolling device 100 includes a pair of rollers 10. The roller surface of each roller 10 is provided with a plurality of annular grooves 11 arranged at intervals along the axial direction P thereof, each annular groove 11 is arranged around the central axis of the roller 10, and a rolling section 12 is formed between two adjacent annular grooves 11. In particular, along the axial direction P of the roller 10, the diameter of the rolling section 12 gradually decreases from the middle to both ends of the rolling section 12.

[0061] In some embodiments, the pole piece 200 includes a current collector and a coating region 21 disposed on the surface of the current collector. The coating region 21 may be disposed on both surfaces of the current collector in the thickness direction Z, or on only one surface of the current collector in the thickness direction Z.

[0062] In some embodiments, the pole piece 200 can be one-out-one. In order to improve the production efficiency, the pole piece 200 can also be one-out-multiple. The pole piece 200 one-out-multiple means that multiple coating areas 21 are coated at intervals on the wider surface of the current collector, and the area of ​​the current collector without the coating area 21 can be used as the pole ear 22. After the pole piece 200 is rolled by the rolling device 100, it is cut along the intervals between the multiple coating areas 21 to obtain multiple sub-pole pieces 201 with smaller widths, such as one-out-two, one-out-three, etc. For example, Figure 4 As shown, the pole piece 200 can be cut along the dividing line D to obtain three sub-pole pieces 201 .

[0063] The pole piece 200 mentioned in this embodiment includes a coating area 21 and a pole ear 22. It can be understood that, for a sub-pole piece 201, each sub-pole piece 201 includes a coating area 21 and a pole ear 22. Figure 5 and Figure 6 Taking a sub-electrode 201 as an example, the coating area 21 includes a coating area body 212 and a coating area edge 211. Due to the coating process, the coating area edge 211 is thinned, and the thickness of the coating area edge 211 is less than the thickness of the coating area body 212.

[0064] In the rolling device 100, the roller surface of each roller 10 is provided with a plurality of annular grooves 11 arranged at intervals along the axial direction P thereof. The annular grooves 11 are concave structures formed on the roller surface of the roller 10, and each annular groove 11 extends along the circumference of the roller 10. There may be two or more annular grooves 11. If there are two annular grooves 11, a rolling section 12 is formed between the two annular grooves 11, which is suitable for one-to-one production of pole pieces 200. If there are more than two annular grooves 11, multiple rolling sections 12 may be formed, which is suitable for one-to-many production of pole pieces 200. For example, as Figures 1 to 3 As shown, there are four annular grooves 11, forming three rolling sections 12, which is suitable for three pole pieces 200.

[0065] Along the axial direction P of the rolling roller 10, the diameter of the rolling section 12 gradually decreases from the middle to the two ends of the rolling section 12. It can be understood that the rolling section 12 is larger in the middle and smaller at the two ends.

[0066] In some embodiments, when the rolling device 100 rolls the pole piece 200 , the width direction X of the pole piece 200 is parallel to the axial direction P of the roller 10 , and the length direction Y of the pole piece 200 is parallel to the running direction of the pole piece 200 .

[0067] In this embodiment, refer to Figure 1 A gap is formed between the pair of rollers 10 for the pole piece 200 to pass through, wherein a gap A is formed between the annular grooves 11 of the pair of rollers 10, and a gap B is formed between the rolling sections 12 of the pair of rollers 10. The main body 212 of the coating area passes through the gap B, and the rolling section 12 rolls the main body 212 of the coating area. The edge 211 of the coating area passes through the gap A, and the annular groove 11 corresponds to the edge 211 of the coating area and the pole ear 22, refer to Figure 3 and Figure 6 The connection position E between the surface of the rolling section 12 and the groove corresponds to the connection position F between the coating area body 212 and the coating area edge 211 .

[0068] It should be understood that the higher the step formed by the connection position E between the surface of the rolled section 12 and the groove, the greater the stress at the connection position F between the main body 212 of the coating area and the edge 211 of the coating area, and the lower the step formed by the connection position E between the surface of the rolled section 12 and the groove, the smaller the stress at the connection position F between the main body 212 of the coating area and the edge 211 of the coating area.

[0069] For the cylindrical roller 10, the roller 10 will bend and deform during rolling, causing the two ends of the roller 10 to be close together and the middle to be far away, which worsens the thickness difference between the coating area main body 212 and the coating area edge 211. Although the annular groove 11 is provided on the roller surface to alleviate the effect of the roller 10 deflection on the thickness of the coating area 21, the connection position of the annular groove 11 and the rolling section 12 will cause stress concentration at the connection between the coating area edge 211 and the coating area main body 212, causing the coating area 21 to crack or fall off.

[0070] In this embodiment, the annular groove 11 can reduce the rolling force on the edge 211 of the coating area, reduce the thickness difference between the main body 212 of the coating area and the edge 211 of the coating area, and improve the thickness consistency of the coating area 21. Along the axial direction P of the roller 10, the diameter of the rolling section 12 gradually decreases from the middle to the two ends of the rolling section 12. In this way, the two ends of the rolling section 12 are smaller, and the steps formed at the positions where the two ends of the rolling section 12 are connected to the annular groove 11 are lower, which can alleviate the stress concentration at the position where the main body 212 of the coating area and the edge 211 of the coating area are connected, reduce the risk of cracking or falling off of the coating area 21, improve the quality of the pole piece 200, and improve the reliability of the battery cell.

[0071] In some embodiments, the rolling section 12 is a rotating body, and the generatrix of the outer peripheral surface of the rolling section 12 is an arc line.

[0072] The generatrix of the outer peripheral surface of the rolling section 12 is a boundary figure of the plane figure constituting the rotating body. The boundary figure rotates around the central axis of the rolling roller 10 to form a three-dimensional shape, namely the rolling section 12.

[0073] The generatrix of the outer circumference of the rolling section 12 is an arc line, which can refer to any curved line, such as an ellipse, an ellipse, or a curve segment between any two points on a parabola. Optionally, the generatrix of the outer circumference of the rolling section 12 is a circular arc line.

[0074] In this embodiment, the generatrix of the outer peripheral surface of the rolling section 12 is an arc line, which can further alleviate the stress concentration of the coating area body 212 and reduce the risk of cracking or falling off of the coating area body 212.

[0075] In some embodiments, the roller 10 is a rotating body.

[0076] In some embodiments, along the axial direction P of the roll 10, the diameters of both ends of the rolling section 12 are equal. That is, the sizes of both ends of the rolling section 12 are consistent.

[0077] In this embodiment, the two ends of the rolling section 12 are of the same size, which can improve the consistency of the roller 10 and reduce the difficulty of preparing the roller 10.

[0078] In some embodiments, the difference between the maximum diameter of the rolling section 12 and the minimum diameter of the rolling section 12 is Δφ, which satisfies 0um<Δφ≤40um. In this way, the difference between the maximum diameter of the rolling section 12 and the minimum diameter of the rolling section 12 is small, and the bulging degree in the middle of the rolling section 12 along the radial direction of the roller 10 is low, which can reduce the impact on the thickness consistency of the coating area body 212.

[0079] If the diameters at both ends of the rolling section 12 are the same, the value obtained by subtracting the diameter of any end of the rolling section 12 from the maximum diameter of the rolling section 12, that is, the difference between the maximum diameter of the rolling section 12 and the minimum diameter of the rolling section 12 is △φ.

[0080] If the diameters at both ends of the rolling section 12 are different, the value obtained by subtracting the diameter of the smallest end of the rolling section 12 from the maximum diameter of the rolling section 12, that is, the difference between the maximum diameter of the rolling section 12 and the minimum diameter of the rolling section 12 is △φ.

[0081] Exemplarily, Δφ may be 0.2um, 3um, 10um, 12um, 15um, 18um, 24um, 27um, 30um, 33um, 37um, 40um and any value therebetween.

[0082] In some embodiments, 4um≤Δφ≤30um.

[0083] Exemplarily, Δφ may be 4um, 7um, 10um, 12um, 15um, 18um, 20um, 24um, 27um, 29um, 30um and any value therebetween.

[0084] 4um≤△φ, the bulging degree in the middle of the rolling section 12 will not be too low, and the step formed at the connection position of the rolling section 12 and the annular groove 11 is low, which can alleviate the stress concentration at the connection position of the coating area main body 212 and the coating area edge 211; △φ≤30um, the bulging degree in the middle of the rolling section 12 will not be too large, and the bulging degree in the middle of the rolling section 12 will not be too high, which can further reduce the impact of the rolling section 12 on the thickness consistency of the coating area main body 212. Therefore, 4um≤△φ≤30um can alleviate the stress concentration at the connection position of the coating area main body 212 and the coating area edge 211, and improve the thickness consistency of the coating area 21.

[0085] Reference Figure 3 In some embodiments, the annular groove 11 includes a groove bottom surface 111 and a groove side surface 112 connected to the groove bottom surface 111 , and the outer peripheral surface of the rolling section 12 is connected to the groove side surface 112 .

[0086] One end of the groove side surface 112 is connected to the outer peripheral surface of the rolling section 12, and the other end of the groove side surface 112 is connected to the groove bottom.

[0087] A step is formed at the position where the groove side surface 112 is connected to the surface of the rolling section 12, which can alleviate the rolling force on the edge 211 of the coating area to a large extent.

[0088] Reference Figure 3 In some embodiments, along the radial direction of the roller 10, the height difference between the end of the rolling section 12 and the groove bottom surface 111 is △H, satisfying 0um<△H≤20um.

[0089] The height difference between the end of the rolling section 12 and the groove bottom surface 111 is ΔH, which can be understood as the height difference between the end of the rolling section 12 and the groove bottom surface 111 .

[0090] Exemplarily, ΔH may be 1um, 3um, 5um, 9um, 11um, 13um, 17um, 19um, 20um and any value therebetween.

[0091] In this embodiment, 0um<△H, the end of the rolling section 12 has a height difference with the groove bottom surface 111, which can alleviate the rolling force on the edge 211 of the coating area, reduce the thickness difference between the coating area body 212 and the edge 211 of the coating area, and improve the thickness consistency of the coating area 21; △H≤20um, the height difference between the end of the rolling section 12 and the groove bottom surface 111 will not be too large, so that the groove bottom surface 111 can roll the edge 211 of the coating area, and improve the compaction density of the edge 211 of the coating area. Therefore, 0um<△H≤20um can take into account both the thickness consistency and the compaction density of the coating area 21.

[0092] In some embodiments, 10 um≤ΔH≤20 um, which can further take into account the thickness consistency of the coating area 21 and the compaction density of the coating area 21 .

[0093] Exemplarily, ΔH may be 10um, 11um, 12um, 13um, 14um, 15um, 16um, 17um, 18um, 19um, 20um and any value therebetween.

[0094] In some embodiments, the rolled section 12 transitions to the groove side surface 112 in a circular arc.

[0095] The arc transition between the rolled section 12 and the groove side surface 112 means that the surface of the rolled section 12 and the groove side surface 112 are in an arc transition.

[0096] The arc transition between the rolling section 12 and the groove side surface 112 can further alleviate the stress concentration at the connection position between the edge 211 of the coating area and the main body 212 of the coating area.

[0097] In some embodiments, the groove side surface 112 and the groove bottom surface 111 have an arc transition, which can improve the structural strength of the roller 10 .

[0098] Figure 7 Schematic diagram of the structure of the roller 10 in some other embodiments of the present application. Figure 7 In other embodiments, the groove side surface 112 may be eliminated, that is, the outer peripheral surface of the rolling section 12 is connected to the groove bottom surface 111. This is suitable for rolling. For a pole piece 200 with a small total thickness of the coating area 21, there does not need to be a large height difference between the outer peripheral surface of the rolling section 12 and the groove bottom of the groove, so the groove side surface 112 may be eliminated.

[0099] In some embodiments, along the axial direction P of the roller 10, the multiple annular grooves 11 include two first annular grooves 11a located at both ends and at least one second annular groove 11b located between the two first annular grooves 11a, and the groove depth of the second annular groove 11b is less than the groove depth of the first annular groove 11a.

[0100] It can be understood that the distance between the groove bottom surface 111 of the first annular groove 11 a and the central axis of the roller 10 is smaller than the distance between the groove bottom surface 111 of the second annular groove 11 b and the central axis of the roller 10 .

[0101] The groove depth may be understood as the dimension of the groove side surface 112 along the radial direction of the roller 10 .

[0102] The second annular groove 11b may be one or more. Figure 3 In the embodiment, two second annular grooves 11 b are provided.

[0103] During the rolling process of the roller 10, the roller 10 as a whole will bend and deform, which will worsen the thickness difference between the edge 211 of the coating area and the main body 212 of the coating area, and the degree of deterioration will gradually increase from the middle to the two ends of the roller 10. Therefore, by making the groove depth of the second annular groove 11b smaller than the groove depth of the first annular groove 11a, the rolling force on the coating area 21 corresponding to the second annular groove 11b is smaller than the rolling force on the coating area 21 corresponding to the first annular groove 11a, which can alleviate the influence of the deflection of the roller 10 on the thickness consistency of the coating area 21.

[0104] It can be understood that the roller 10 produces deflection deformation, which worsens the thickness difference between the edge 211 of the coating area and the main body 212 of the coating area. The greater the degree of deterioration, the deeper the groove 11 can be, and the less deterioration, the shallower the groove 11 can be.

[0105] In some embodiments, along the axial direction P of the roller 10 , the depth of the annular groove 11 gradually increases from the middle of the roller 10 to the two ends of the roller 10 .

[0106] The embodiment of the present application further provides a battery manufacturing device, which includes the above-mentioned rolling device 100.

[0107] Reference Figures 1 to 3The embodiment of the present application also provides a rolling device 100, which includes a pair of rollers 10. The roller surface of each roller 10 is provided with four annular grooves 11 arranged at intervals along the axial direction P thereof, each annular groove 11 is arranged around the central axis of the roller 10, and a rolling section 12 is formed between two adjacent annular grooves 11. Along the axial direction P of the roller 10, the diameter of the rolling section 12 gradually decreases from the middle to the two ends of the rolling section 12. The rolling section 12 is a rotating body, and the generatrix of the outer peripheral surface of the rolling section 12 is an arc line. Along the axial direction P of the roller 10, the diameters of the two ends of the rolling section 12 are equal. The annular groove 11 includes a groove bottom surface 111 and a groove side surface 112 connected to the groove bottom surface 111, and the outer peripheral surface of the rolling section 12 is connected to the groove side surface 112. The rolling section 12 and the groove side surface 112 are in a circular arc transition. Along the radial direction of the roller 10, the groove depth of the annular groove 11 gradually increases from the middle to the two ends of the roller 10. Along the radial direction of the roller 10 , from the middle to both ends of the roller 10 , the distance between the groove bottom surface 111 of the annular groove 11 and the central axis of the roller 10 gradually decreases.

[0108] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0109] The above embodiments are only used to illustrate the technical solution of the present application and are not used to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A rolling device for rolling a pole piece, wherein the pole piece comprises a coating area and a pole ear, characterized in that: The rolling device comprises a pair of rollers; The roller surface of each roller is provided with a plurality of annular grooves spaced apart along the axial direction thereof, each of the annular grooves is arranged around the central axis of the roller, and a rolling section is formed between two adjacent annular grooves; Wherein, along the axial direction of the rolling roller, from the middle to both ends of the rolling section, the diameter of the rolling section gradually decreases.

2. The rolling device according to claim 1, characterized in that: The rolling section is a rotating body, and the generatrix of the outer peripheral surface of the rolling section is an arc line.

3. The rolling device according to claim 1, characterized in that: Along the axial direction of the rolling roller, the diameters of both ends of the rolling section are equal.

4. The rolling device according to any one of claims 1 to 3, characterized in that: The difference between the maximum diameter of the rolling section and the minimum diameter of the rolling section is △φ, which satisfies 0um<△φ≤20um.

5. The rolling device according to claim 4, characterized in that: 2um≤△φ≤15um.

6. The rolling device according to any one of claims 1 to 3, characterized in that: The annular groove comprises a groove bottom surface and a groove side surface connected to the groove bottom surface, and the outer peripheral surface of the rolling section is connected to the groove side surface.

7. The rolling device according to claim 6, characterized in that: Along the radial direction of the rolling roller, the height difference between the end of the rolling section and the bottom surface of the groove is △H, which satisfies 0um<△H≤20um.

8. The rolling device according to claim 7, characterized in that: 10um≤△H≤20um.

9. The rolling device according to claim 6, characterized in that: The rolling section transitions to the groove side surface in a circular arc.

10. The rolling device according to any one of claims 1 to 3, characterized in that: Along the axial direction of the roller, the plurality of annular grooves include two first annular grooves located at both ends and at least one second annular groove located between the two first annular grooves, and the groove depth of the second annular groove is smaller than the groove depth of the first annular groove.

11. A battery manufacturing device, characterized in that: It comprises the rolling device as described in any one of claims 1-10.

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