Embossing roller and embossing system for battery pole piece

Abstract

The embodiment of the utility model provides an embossing roller and an embossing system for a battery pole piece. The knurling roller of the battery pole piece comprises a roller body, the cross section of the roller body is a circular section, a plurality of knurling protruding parts are arranged on the peripheral wall of the roller body, the knurling protruding parts are distributed in a multi-circle mode, and the height of each circle of knurling protruding part is increased firstly and then decreased in the axial direction of the roller body so as to change flexural deformation of the pole piece. By arranging the embossed convex parts with different heights, the consistency of the transverse thickness of the whole pole piece can be improved while embossing is carried out, so that the occurrence of poor embossing or breakage of the pole piece is reduced. According to the embossing roller of the battery pole piece disclosed by the embodiment of the utility model, the problem that the pole piece is broken due to embossing deformation in a rolling process can be reduced or even avoided by pre-pressing the curvature of the pole piece.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to an embossing roller for battery electrodes and an embossing system having the embossing roller for battery electrodes. Background Technology

[0002] To improve the power density of battery cells, laser etching can be used to create recessed structures of different shapes on the electrodes. This improves the porosity of the positive electrode, enhances the electrolyte's wetting ability and the electrode's electrolyte retention capacity during long cycles, thereby improving the cell's power and cycle performance. However, laser etching increases manufacturing costs. Related technologies use embossing rollers to create electrodes with recessed structures, which is relatively low-cost. However, electrodes produced by conventional rolling often exhibit a thicker center and thinner edges due to bending deformation (e.g., ...). Figure 1 This can cause the electrode sheets to bend. After later winding, the electrode sheets can deform severely, and inconsistent tension can lead to problems such as wrinkling and breakage. At the same time, because the electrode sheets are not flattened after embossing, some defective locations may pose a risk of lithium plating during the cell's charging and discharging process. Utility Model Content

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, embodiments of this invention propose an embossing roller for battery electrodes. This embossing roller, by pre-pressing the electrode, can reduce or even avoid the problem of electrode wrinkling and breakage caused by embossing deformation during the rolling process.

[0004] An embodiment of this utility model also proposes an embossing system for battery electrodes.

[0005] The embossing roller for the battery electrode sheet according to this utility model embodiment includes a roller body. The cross-section of the roller body is circular, and a plurality of embossing protrusions are provided on the outer peripheral wall of the roller body. The plurality of embossing protrusions are arranged in multiple rings, and the height of the embossing protrusions in each ring first increases and then decreases in the axial direction of the roller body to change the flexural deformation of the electrode sheet.

[0006] The embossing roller for the battery electrode sheet in this embodiment of the invention forms embossing on the electrode sheet by providing multiple rings of embossing protrusions on the outer peripheral wall of the roller body. This embossing helps to increase the compaction density of the electrode sheet, thereby improving the overall energy density of the battery. Furthermore, by first increasing and then decreasing the height of each ring of embossing protrusions along the axial direction of the roller body, pre-bending the electrode sheet can offset some of the deflection deformation. That is, by applying a certain pressure to the electrode sheet through the embossing roller, the electrode sheet exhibits a characteristic of being thinner in the middle and thicker at the edges. Since the embossing roller is located upstream of the roller press, it is directly wound after embossing to form a core. This avoids deformation of the embossed shape caused by winding after embossing in the roller pressing process, thus making the transverse thickness of the entire electrode sheet more uniform and reducing the occurrence of poor embossing or breakage of the electrode sheet.

[0007] The embossing roller of the battery electrode in this embodiment of the invention can reduce or even avoid the problem of electrode breakage caused by embossing deformation during the rolling process by pre-pressing the electrode.

[0008] In some embodiments, the highest embossing protrusion is located in the middle region along the length of the roller.

[0009] In some embodiments, the embossing protrusions on both sides of the highest embossing protrusion are symmetrically arranged along the axial direction of the roller.

[0010] In some embodiments, the embossed protrusion is a hemispherical protrusion.

[0011] In some embodiments, adjacent rings of embossed protrusions are staggered along the axial direction of the roller body, or adjacent rings of embossed protrusions are arranged in a row.

[0012] In some embodiments, the height of the maximum embossed protrusion is 0.1mm-5mm.

[0013] In some embodiments, the height of adjacent embossed protrusions decreases sequentially by a ratio of 1% to 10%.

[0014] In some embodiments, the height difference between two adjacent embossed protrusions is 3μm-30.0μm.

[0015] In some embodiments, the spacing between adjacent embossed protrusions is 1μm-20μm.

[0016] In some embodiments, the number of embossed protrusions per circle is 5-99, and the size and shape of the embossed protrusions in each circle are consistent.

[0017] In some embodiments, the roller body is a plastic roller.

[0018] The embossing system for battery electrode sheets according to this utility model embodiment includes an unwinding mechanism, a pressure control device, an embossing roller, a roller press, and a winding mechanism arranged in sequence. The embossing roller is the embossing roller according to any one of the above-mentioned methods. The embossing roller is rotatably mounted on the pressure control device. The unwinding mechanism is used to unwind the electrode sheet, and the winding mechanism is used to wind the electrode sheet.

[0019] In some embodiments, the roller press includes a roller brush, an upper roller and a lower roller disposed opposite to each other along the thickness direction of the electrode sheet, and the electrode sheet is disposed between the upper roller and the lower roller.

[0020] In some embodiments, the pressure control range of the pressure control device is 0-5 MPa. Attached Figure Description

[0021] Figure 1 This is a thickness distribution diagram of the electrode sheet after roll forming due to bending deformation in related technologies.

[0022] Figure 2 This is a thickness distribution diagram of the battery electrode sheet after embossing roller in an embodiment of this utility model.

[0023] Figure 3 This is a schematic diagram of the embossing system in an embodiment of this utility model.

[0024] Figure 4 This is a schematic diagram showing the unfolded shape of the embossing roller of the battery electrode sheet in an embodiment of this utility model.

[0025] Figure 5 This is a cross-sectional view of the embossing roller of the battery electrode sheet in an embodiment of this utility model.

[0026] Figure label:

[0027] Embossing roller 10; unwinding mechanism 20; pressure control device 30; roller press 40; upper roller 401; lower roller 402;

[0028] 50 winding machines;

[0029] Roller body 1;

[0030] Embossed raised part 2. Detailed Implementation

[0031] The embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0032] The following is for reference. Figures 2-5 The embossing roller 10 and embossing system of the battery electrode sheet are described in an embodiment of the present invention.

[0033] The embossing roller 10 for the battery electrode sheet in this embodiment of the present invention includes a roller body 1. The roller body 1 has a circular cross-section, and a plurality of embossing protrusions 2 are provided on the outer peripheral wall of the roller body 1. The plurality of embossing protrusions 2 are arranged in multiple rings, and the height of each ring of embossing protrusions 2 first increases and then decreases in the axial direction of the roller body 1, so as to change the bending deformation of the electrode sheet during the embossing process.

[0034] The embossing roller 10 of the battery electrode in this embodiment of the invention forms embossing on the electrode by providing multiple rings of embossing protrusions 2 on the outer peripheral wall of the roller body 1. This embossing on the electrode helps to increase the compaction density of the electrode, thereby increasing the overall energy density of the battery. Furthermore, by first increasing and then decreasing the height of each ring of embossing protrusions 2 along the axial direction of the roller body 1, pre-bending the electrode can offset some of the deflection deformation. That is, by applying a certain pressure to the electrode through the embossing roller 10, the electrode exhibits a characteristic of being thinner in the middle and thicker at the edges (e.g., ...). Figure 2 Since the embossing roller 10 is located upstream of the roller press 40, it is directly wound to form a core after embossing. This avoids the deformation of the embossed shape caused by winding after embossing in the roller pressing process, so that the thickness of the entire electrode sheet in the lateral direction is close to uniform, which can reduce the occurrence of poor embossing or breakage of the electrode sheet.

[0035] The embossing roller 10 of the battery electrode in this embodiment of the invention can reduce or even avoid the problem of electrode breakage caused by embossing deformation during the rolling process by pre-pressing the electrode.

[0036] like Figure 4 and Figure 5 As shown, the highest embossing protrusion 2 is located in the middle region along the length of the roller body 1.

[0037] The embossing roller 10 of the battery electrode sheet in this embodiment of the utility model sets the highest embossing protrusion 2 in the middle region of the roller body 1 along the length direction, so that the middle region of the electrode sheet has a relatively large pre-bending degree, thereby further improving the uniformity of the electrode sheet in the lateral thickness.

[0038] like Figure 4 and Figure 5 As shown, the embossing protrusions 2 on both sides of the highest embossing protrusion 2 are symmetrically arranged along the axial direction of the roller body 1. Because the electrode sheet exhibits a characteristic of being thinner in the middle and thicker at the edges, the embossing protrusions 2 on both sides of the highest embossing protrusion 2 are positioned at the very center of the roller body 1. Thus, the embossing roller 10 achieves a symmetrical pre-bending effect on the electrode sheet. This further improves the lateral thickness uniformity of the electrode sheet.

[0039] like Figure 4 and Figure 5 As shown, the embossed protrusion 2 is a hemispherical protrusion. Compared to square, rhomboid, or other irregular shapes, the hemispherical embossed protrusion 2 used in this application allows for a more uniform distribution of stress when subjected to external forces, reducing the problem of localized stress concentration. Furthermore, this helps prevent cracking or delamination of the electrode sheet due to material expansion and contraction during charge-discharge cycles. Moreover, the hemispherical protrusion is less prone to burr generation during the pressing process, reducing the risk of short circuits and contributing to improved battery safety performance.

[0040] The embossed protrusions 2 of two adjacent rings are staggered along the axial direction of the roller body 1.

[0041] The embossing roller 10 of the battery electrode in this embodiment of the invention provides more contact points within a limited space by staggering the embossing protrusions 2 of adjacent rings along the axial direction of the roller body 1, thereby increasing the actual contact area between the active material and the current collector. This helps to improve electron conduction efficiency, reduce interface resistance, and thus improve the overall performance of the battery. In addition, the staggered protrusion structure enhances the mechanical strength of the electrode, especially when facing internal pressure changes or external physical impacts, better maintaining the integrity and functionality of the electrode and preventing delamination or cracking of the electrode.

[0042] like Figure 4 As shown, the embodiments of this utility model are not limited to this. For example, in other embodiments, the embossed protrusions 2 of two adjacent rings can also be arranged in a row.

[0043] The height of the largest embossed protrusion 2 is 0.1mm-5mm.

[0044] The embossing roller 10 of the battery electrode in this embodiment limits the height of the maximum embossing protrusion 2. This avoids situations where the embossing protrusion 2 is too high, potentially causing excessive pressure on the coating layer during pressing, weakening the bond between the active material and the current collector, and increasing the risk of active material peeling off. Furthermore, the embossing protrusion 2 generates significant localized pressure during pressing, easily leading to stress concentration and causing electrode breakage or delamination. Conversely, it avoids situations where the embossing protrusion 2 is too low, failing to provide sufficient contact points, reducing the effective contact area between the active material and the current collector, lowering electron conduction efficiency, increasing interface resistance, and ultimately affecting battery performance.

[0045] Optionally, the height of the largest embossed protrusion 2 can be 0.1mm, 0.2mm, 0.5mm, 0.8mm, 1.0mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm and 5.0mm.

[0046] The height of adjacent embossed protrusions decreases sequentially by 1%-10%. This creates a relatively smooth flexural deformation, further improving the consistency of the electrode thickness after embossing.

[0047] Optionally, the height of adjacent embossed protrusions decreases sequentially by 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%.

[0048] The height difference between the embossed protrusions 2 of two adjacent rings is 3μm-30.0μm. This avoids the problem of inconsistent lateral thickness of the electrode caused by excessive pre-bending of the electrode due to excessive embossing height difference.

[0049] Optionally, the height difference between two adjacent embossed protrusions 2 is 3μm, 6μm, 9μm, 12μm, 15μm, 18μm, 20μm, 22μm, 24μm, 26μm, 28μm and 30μm.

[0050] The spacing between adjacent embossed protrusions 2 is 1μm-20μm. Optionally, the spacing between adjacent embossed protrusions 2 can be 1μm, 3μm, 6μm, 9μm, 12μm, 15μm, 18μm and 20μm.

[0051] The embossing roller 10 of the battery electrode in this embodiment of the invention limits the spacing between adjacent embossed protrusions 2. This avoids two problems: firstly, excessive spacing (meaning a reduced number of embossed protrusions 2 per unit area), which would decrease the effective contact area between the active material and the current collector. Excessive spacing weakens electron conduction efficiency, increases interface resistance, and reduces the overall performance of the battery; secondly, it avoids excessively dense protrusions, which would generate greater local pressure during pressing, further increasing the risk of electrode delamination or breakage. Therefore, the embossing roller 10 of the battery electrode in this embodiment of the invention further reduces the risk of electrode breakage.

[0052] Furthermore, the number of embossed protrusions 2 in each ring is 5-99, and the size and shape of the embossed protrusions 2 in each ring are consistent.

[0053] Roller 1 is a plastic roller. Because plastic rollers have a certain degree of flexibility, they can better adapt to the irregularities of the electrode surface during the pressing process, reducing damage to the electrode. Especially when processing thinner or softer electrodes, plastic rollers can provide a gentler pressure distribution, avoiding excessive pressure damage.

[0054] Alternatively, the plastic roller can be a butadiene rubber roller, a styrene-butadiene rubber roller, a nitrile rubber roller, or a chloroprene rubber roller.

[0055] The embossing system for battery electrode sheets according to an embodiment of the present invention includes an unwinding mechanism 20, a pressure control device 30, an embossing roller 10, a roller press 40, and a winding mechanism 50 arranged sequentially. The embossing roller 10 is any of the embossing rollers described above. The embossing roller 10 is rotatably mounted on the pressure control device 30. The unwinding mechanism 20 is used to unwind the electrode sheets, and the winding mechanism 50 is used to wind the electrode sheets.

[0056] Therefore, the embossing system for the battery electrode sheet in this embodiment of the invention reduces or eliminates electrode sheet deformation, preventing serious impact on subsequent rolling. Simultaneously, the rolling press 40 avoids the embossing shape from rebounding after a period of rest, thus improving both the compaction density of the battery electrode sheet and mitigating the problem of excessive expansion during charging and discharging.

[0057] The roller press 40 includes a roller brush, an upper roller 401 and a lower roller 402 arranged opposite to each other along the thickness direction of the electrode sheet, and the electrode sheet is inserted between the upper roller 401 and the lower roller 402.

[0058] The embossing system of the battery electrode sheet in this embodiment of the invention can remove the dust generated by the embossing roller 10, thus effectively solving the risk of dust generation by the embossing roller 10.

[0059] The pressure control range of the pressure control device 30 is 0-5 MPa.

[0060] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0061] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0062] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0063] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0064] In this utility model, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0065] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. An embossing roll for battery pole pieces, characterized in that The embossing roller comprises: a roller body with a circular cross section, a plurality of embossing protrusions arranged on the outer peripheral wall of the roller body, and the height of the embossing protrusions in each circle increases first and then decreases in the axial direction of the roller body to change the deflection of the pole piece.

2. The embossing roll for battery pole sheets according to claim 1, characterized in that The highest embossing protrusion is arranged at the middle region of the length direction of the roller body. And / or, the embossing protrusions on both sides of the highest embossing protrusion are symmetrically arranged along the axial direction of the roller body.

3. The embossing roller of the battery pole piece according to claim 1, wherein: the embossing protrusions are hemispherical protrusions; adjacent two circles of the embossing protrusions are staggered along the axial direction of the roller body, or adjacent two circles of the embossing protrusions are arranged in a line.

4. The embossing roll for battery pole sheets according to claim 1, characterized in that, The height of the largest embossing protrusion is 0.1mm-5mm.

5. The embossing roller of the battery pole piece according to claim 4, wherein: the height of adjacent embossing protrusions decreases by 1%-10% in turn; and / or, the height difference between adjacent two circles of the embossing protrusions is 3μm-30.0μm.

6. The embossing roll for battery pole sheets according to claim 4, characterized in that The distance between adjacent embossing protrusions is 1μm-20μm.

7. The embossing roll for battery pole sheets according to claim 4, characterized in that The number of embossing protrusions in each circle is 5-99, and the size and shape of the embossing protrusions in each circle are consistent.

8. The embossing roll for battery pole sheets according to any of claims 1 - 7, characterized in that, The roller body is a plastic roller.

9. An embossing system of a battery electrode sheet, characterized by, The device comprises a unwinding mechanism, a pressure control device, an embossing roller, a roller press and a winding mechanism arranged in turn, the embossing roller is according to any one of claims 1-7, the embossing roller is rotatably arranged on the pressure control device, the unwinding mechanism is used for unwinding the pole piece, and the winding mechanism is used for winding the pole piece.

10. The embossing system of the battery pole piece of claim 9, wherein, The roller press comprises a roller brush, an upper roller and a lower roller oppositely arranged along the thickness direction of the pole piece, and the pole piece is arranged between the upper roller and the lower roller. And / or, the pressure control range of the pressure control device is 0-5Mpa.

Images