Pole piece, pole piece preparation method and preparation equipment, battery monomer and electric device

Abstract

The application relates to a pole piece, a pole piece preparation method and a preparation device, a battery monomer and an electric device. The pole piece comprises a main body and a pole lug. The main body comprises a first coating area. The pole lug is protruded on one side of the main body along the width direction of the main body, and the pole lug comprises a second coating area and a hollow foil area. The first coating area, the second coating area and the hollow foil area are sequentially adjacent along the width direction. The pole lug comprises a top edge and side edges arranged on both sides of the top edge along the extension direction of the main body. The top edge and the main body are arranged on the opposite sides of the side edges in the width direction. The top edge comprises first arc edges located at both ends of the top edge. The first arc edges are connected with the side edges and are opposite to the main body bending. The included angle between the tangent lines at the connection positions of the first arc edges and the side edges is theta 2, and 15 DEG <= theta 2 < 90 DEG. The technical scheme of the application can improve the cutting quality of the pole lug and improve the reliability of the battery.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to electrode sheets, electrode sheet preparation methods and equipment, battery cells and electrical devices. Background Technology

[0002] The current generated by the battery cell during charging and discharging needs to be efficiently and stably led out to the external circuit. This is typically achieved using a dedicated conductive connector, the tab, which is a key component for this purpose. When tabs are cut from bare electrode sheets, burrs and other defects can easily appear at the edges, reducing battery reliability. Summary of the Invention

[0003] Therefore, it is necessary to provide an electrode sheet and its preparation method, as well as a battery cell, to address the problems of poor processing structure such as burrs on the edge of the electrode tab, which reduces battery reliability.

[0004] Firstly, this application proposes an electrode sheet comprising: The main body includes the first coating area; The electrode tab protrudes from one side of the main body along the width direction. The electrode tab includes a second coating area and an empty foil area. The first coating area, the second coating area and the empty foil area are sequentially adjacent to each other along the width direction. The electrode includes a top edge and side edges arranged on both sides of the top edge along the extension direction of the body. The top edge and the body are arranged on opposite sides of the side edges in the width direction. The top edge includes first arc edges located at both ends thereof. The first arc edges are connected to the side edges and bend away from the body. The angle between the tangents at the connection point of the first arc edge and the side edge is θ2, where 15°≤θ2<90°.

[0005] In some embodiments, 20°≤θ2≤60°.

[0006] In some embodiments, the tabs are symmetrically arranged along a plane perpendicular to the extension direction.

[0007] In some embodiments, the body includes an end edge connected to the side edge, the end edge being located at the edge of the first coating area, and the end edge being a straight edge.

[0008] In some embodiments, the top edge includes an intermediate segment connecting the two first arc edges, the intermediate segment being a curved edge, a straight edge, or an arc edge that is smoothly connected to the first arc edges.

[0009] In some embodiments, the middle segment is a straight edge; The first arc edge has a heat-affected zone, while the middle section does not; or, the surface roughness of the first arc edge is less than that of the middle section.

[0010] In some embodiments, each of the side edges includes a side slope connected to the first arc edge, and each side slope is inclined toward the other side edge in a direction pointing toward the top edge.

[0011] In some embodiments, each of the side edges further includes a second arc edge, which transitionally connects the end edge of the body and the side slope edge, and the second arc edges of the two side edges bend toward each other.

[0012] In some embodiments, each of the side edges intersects the corresponding first arc edge at position p, the first boundary between the second coating area and the empty foil area intersects the side edge at position A, the position of the top edge furthest from the body along the width direction of the body is position b, and the inclination angle of the side slope is θ1. Along the width direction of the main body, the distance between position p and position b is L2, the distance between position b and position A is L3, and the protrusion dimension of the tab along the width direction is L4; The electrode sheet satisfies at least one of the following conditions: 1 / 8 < L2 / L3 < 1; 1mm≤L4-L3≤5mm; and, 0°<θ1≤15°.

[0013] In some embodiments, the first coating region and the second coating region are electrode material coating regions of the same material; or... The first coating area includes a first sub-area and a second sub-area that are adjacent to each other along the width direction. The first sub-area is an electrode material coating area, and the second sub-area and the second coating area are adjacent to each other and are both insulating material coating areas of the same material.

[0014] Secondly, this application proposes a method for preparing electrode sheets, including: The laser cutting device is invoked to perform a tab cutting operation on the bare electrode sheet located in its working plane along a set trajectory, so as to process the bare electrode sheet into an electrode sheet with tabs; The set trajectory is located in the xy plane coordinate system determined by the working plane. The bare electrode includes a foil area and a coating area arranged adjacent to each other along the y-axis. The foil area and the coating area are arranged along the x-axis. The foil area includes an outer edge that is away from the coating area. The set trajectory includes a first trajectory passing through the foil area to form the top edge of the electrode sheet and a second trajectory passing through the coating area and the foil area to form the side edge of the electrode sheet; the first trajectory includes a first arc-shaped trajectory segment located in the foil area, the first arc-shaped trajectory segment intersects with the second trajectory in the foil area, the first arc-shaped trajectory segment bends toward the side away from the coating area, and the angle between the first arc-shaped trajectory segment and the tangent of the second trajectory at the connection point is θ2', 15°≤θ2'<90°.

[0015] In some embodiments, the first trajectory includes two first arcuate trajectory segments arranged at intervals along the x-axis, and an intermediate trajectory segment connecting the two first arcuate trajectory segments; The intermediate trajectory segment is located in the foil area and is either straight or curved; or, the intermediate trajectory segment is located outside the range of the bare electrode sheet; or, the intermediate trajectory segment is an arc-shaped trajectory that smoothly connects with each of the first arc-shaped trajectory segments.

[0016] In some embodiments, the second trajectory includes two sub-trajectories; Each of the sub-trajectories includes an end edge trajectory located in the coating area to form the end edge of the electrode sheet, and a side edge trajectory passing through the coating area and the foil area to form the side edge. Each side edge trajectory independently intersects a first arcuate trajectory segment in the foil area, and the end edge trajectory is located on the side of the side edge trajectory away from the first arcuate trajectory segment. Each of the first trajectories intersects with two of the sub-trajectories, and the two sub-trajectories are discontinuously arranged along the x-axis.

[0017] In some embodiments, the laser cutting device travels along the set trajectory toward the positive side of the x-axis to make cuts; Each of the side edge trajectories includes an inclined trajectory segment, each of the inclined trajectory segments intersects with the corresponding first arcuate trajectory segment in the foil area, and extends inclinedly toward the positive x-axis along the cutting travel direction of the laser cutting device.

[0018] In some embodiments, the included angle of inclination for each inclined trajectory segment is θ1', where 0° < θ1' ≤ 15°.

[0019] In some embodiments, each of the side edge trajectories further includes a second arc-shaped trajectory segment, and in the same sub-trajectory, the end edge trajectory, the second arc-shaped trajectory segment, and the inclined trajectory segment are sequentially connected along the x-axis; The second arcuate trajectory segments of the two side edge trajectories that intersect with the same first trajectory bend toward each other.

[0020] In some embodiments, the projection of the boundary line between the coating area and the foil area onto the xy plane coordinate system is used as a first reference line; the foil area includes an outer edge disposed away from the coating area, and the projection of the outer edge onto the xy plane coordinate system is used as a second reference line; The intersection position of the first arc-shaped trajectory segment and the second trajectory is position p', the position of the first trajectory farthest from the coating area is position b', the intersection position of the second trajectory and the first reference line is position A', and the distance between position b' and position A' along the y-axis is L3'; The minimum distance between each of the first trajectories and the second reference line is L1', the maximum distance between the second trajectories and the second reference line is L', and the farthest distance between position b' and the second trajectory along the y-axis is L4', satisfying: 1 / 8 < L2' / L3' < 1; 1mm≤L4'-L3'≤5mm; and / or 1 / 8≤L1' / L'≤7 / 8.

[0021] In some embodiments, invoking a laser cutting device to perform a tab cutting operation on a bare electrode sheet located in its working plane along a predetermined trajectory includes: The first and second laser cutters of the laser cutting device are invoked to perform tab cutting operations on the bare electrode sheet located in the working plane of the laser cutting device along the first and second trajectories toward the positive x-axis, respectively.

[0022] In some embodiments, the set trajectory includes a plurality of second trajectories arranged at intervals along the x-axis, and a plurality of first trajectories arranged at intervals along the x-axis; In particular, among the two sub-trajectories included in at least a portion of the second trajectory, the two end edge trajectories are connected and located between the two side edge trajectories, and in each pair of adjacent second trajectories, the two sub-trajectories arranged in opposite directions intersect with the same first trajectory.

[0023] In some embodiments, the set trajectory further includes a third trajectory and a plurality of first trajectories arranged at intervals along the x-axis; Multiple sets of sub-trajectories are arranged sequentially at intervals along the x-axis. Each set of sub-trajectories intersects with the same first trajectory. In each pair of adjacent sets of sub-trajectories, the end edge trajectories of the two sub-trajectories that are close to each other are connected via the third trajectory.

[0024] In some embodiments, the sub-trajectories of each group, the sub-trajectories located on the same side of the first trajectory are called the first sub-trajectories, and the sub-trajectories on the other side of the same trajectory are called the second sub-trajectories; Accordingly, the laser cutting device is invoked to perform a tab cutting operation on the bare electrode sheet located in its working plane along a set trajectory, including: Multiple laser cutters of the laser cutting device are invoked to perform tab cutting operations on bare electrodes located in the working plane of the laser cutting device, respectively, along the first sub-track, the second sub-track, and the third track in the positive direction of the x-axis.

[0025] In some embodiments, the coating region includes an electrode material coating region and an insulating material coating region disposed adjacently along the y-axis, the insulating material coating region and the foil region being adjacent; the second trajectory is located outside the range of the electrode material coating region and passes through the insulating material coating region; or, The coating area is the electrode material coating area, and the second trajectory passes through the electrode material coating area.

[0026] Thirdly, this application proposes an electrode preparation apparatus, comprising: Laser cutting equipment; and A control device, connected to the laser cutting device, is used to control the operation of the laser cutting device according to the electrode preparation method as described in the second aspect.

[0027] Fourthly, this application provides a battery cell comprising the electrode as described in the first aspect.

[0028] Fifthly, this application provides an electrical device characterized by comprising the battery cell described in the fourth aspect.

[0029] Compared with the prior art, this application has the following beneficial effects: The aforementioned electrode sheet, electrode sheet preparation method and equipment, battery cell and power supply device, because the top edge and side edge of the electrode tab intersect in the empty foil area, and the intersection point is uncoated, burrs caused by coating collapse are less likely to occur. This improves the cutting quality of the tab edge, increases the yield of the electrode sheet and the reliability of the battery. Moreover, the first top edge is non-tangentially connected to the side edge through its first arc edge, and the included angle θ2 of the tangents satisfies 15°≤θ2<90°. This not only improves the cutting efficiency of the tab but also ensures that the tab has a large current-carrying area, thus improving battery performance. Attached Figure Description

[0030] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1' Figure (a) shows a schematic diagram of the laser cutting electrode trajectory in the related technology; Figure 1' Figure (b) shows a schematic diagram of an electrode in the relevant technology; Figure 1 These are schematic diagrams of the electrode structure in some embodiments; Figure 2 for Figure 1 The diagram shows the size distribution of the electrode plates. Figure 3 This is a schematic diagram of the electrode structure in some other embodiments; Figure 4 This is a schematic diagram of the electrode structure in some other embodiments; Figure 5 This is a schematic flowchart of the electrode preparation method for some embodiments; Figure 6 These are schematic diagrams of laser cutting trajectories for some embodiments; Figure 7 for Figure 6 The diagram shows the size distribution of the laser cutting trajectory. Figure 8 This is a schematic diagram of the laser cutting trajectory for some other embodiments; Figure 9 This is a schematic diagram of the laser cutting trajectory of the electrode sheet in some other embodiments; Figure 10 This is a schematic diagram of the laser cutting trajectory of the electrode sheet in some other embodiments; Figure 11 This is a schematic diagram of the external shape of a battery cell in some embodiments; Figure 12 for Figure 11 An exploded view of a single battery cell is shown. Figure 13 This is a structural schematic diagram of a vehicle according to some embodiments.

[0031] The reference numerals in the detailed embodiments are as follows: 10000, Vehicle; 1000, Battery cell; 1100, Electrode assembly; 1200, Housing; 1300, Top cover assembly; 100, Electrode sheet; I1, First boundary line; 10, Main body; t1, First coating area; t11, First sub-area; t12, Second sub-area; Y, Width direction; X, Extension direction; 11, End edge; 20, Tab; t2, Second coating area; t3, Empty foil area; 22, Side edge; 22c, Side bevel; 22d, Second arc edge; 21, Top edge; 21a, First arc edge; 21b, Middle section; 100A, Bare Electrode; T1, Coating area; T2, Foil area; T21, Outer edge; F1, First reference line; F2, Second reference line; t01, Electrode material coating area; t02, Insulating material coating area; G, Set trajectory; G1, First trajectory; G11, First arc-shaped trajectory segment; G12, Middle trajectory segment; G2, Second trajectory; G21, Sub-trajectory; G21c, End edge trajectory; G21d, Side edge trajectory; d1, Inclined trajectory segment; d2, Second arc-shaped trajectory segment; G21A, First sub-trajectory; G21B, Second sub-trajectory; G3, Third trajectory. Detailed Implementation

[0032] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0033] In the description of this application, it should be understood that, where they appear, the terms “center,” “longitudinal,” “lateral,” “length,” “width,” “thickness,” “upper,” “lower,” “front,” “rear,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” “outer,” “clockwise,” “counterclockwise,” “axial,” “radial,” and “circumferential” indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0034] Furthermore, where applicable, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0035] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," "fixing," etc., shall be interpreted broadly. For example, they may refer to a fixed connection, a detachable connection, or an integral part; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; they may refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0036] In this application, unless otherwise expressly 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.

[0037] It should be noted that, if an element is described as "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is described as "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0038] To improve battery production efficiency, related technologies employ multi-laser beams working in tandem to process electrode tabs. The applicant's research found that, referring to... Figure 1' In some technologies, two laser cutters are used to cut the bare electrode 100A to process it into an electrode 100 with tabs 20. This is because the cutting paths of the two laser cutters (determined by...) Figure 1' As indicated by G1' and G2', the trajectories intersect roughly perpendicularly in the coating area T1, with the intersection points often being straight lines. This can easily lead to steps J at a physical level. The sharp corners of steps J are prone to problems such as molten beads and burrs due to coating collapse. These issues become more pronounced under the influence of factors such as fluctuations in incoming materials and mechanical stress. These defects can easily puncture and damage the separator, causing internal short circuits in the battery and significantly reducing battery reliability.

[0039] Based on this, this application proposes an electrode sheet, an electrode sheet preparation method, and preparation equipment, aiming to improve the generation of defective structures at the edge of the electrode sheet, and improve the yield of the electrode sheet and the reliability of the battery.

[0040] Please refer to Figure 1 and Figure 2 The electrode 100 proposed in this embodiment includes a main body 10 and an electrode tab 20. The main body 10 includes a first coating area t1. The electrode tab 20 protrudes from one side of the main body 10 along the width direction Y. The electrode tab 20 includes a second coating area t2 and an empty foil area t3. The first coating area t1, the second coating area t2, and the empty foil area t3 are sequentially adjacent to each other along the width direction Y. The electrode tab 20 includes a top edge 21 and side edges 22 arranged on both sides of the top edge 21 along the extension direction X of the main body 10. The top edge 21 and the main body 10 are arranged on opposite sides of the side edges 22 in the width direction Y. The top edge 21 includes a first arc edge 21a located at both ends. The first arc edge 21a is connected to the side edge 22 and is curved opposite to the main body 10. The included angle between the tangents of the first arc edge 21a and the side edge 22 at the connection point is θ2, where 15°≤θ2<90°.

[0041] Understandably, the electrode 100 includes a current collector and a coating. The current collector can be a conductive material such as copper or aluminum. The current collector of the main body 10 is coated with a coating to form a first coating area t1. The current collector at the root of the electrode tab 20 is coated with a coating to form a second coating area t2. The current collector area of ​​the electrode tab 20 without coating forms an empty foil area t3.

[0042] The coating materials of the second coating region t2 and the first coating region t1 can be the same or different. In one example, the electrode 100 is a positive electrode, the coating material of the second coating region t2 is an insulating material, and the coating material of the first coating region t1 is entirely electrode material or the coating material of a portion of it adjacent to the second coating region t2 is an insulating material. The area where the insulating material is located is at the edge of the electrode 100 coating, which can improve the edge lithium plating problem of the negative electrode that cooperates with the positive electrode. In another embodiment, the electrode 100 is a negative electrode, the first coating region t1 is entirely covered with electrode material, and the coating material of the second coating region t2 is the same electrode material as the coating material of the first coating region t1.

[0043] "Adjacent" means adjacent to each other. The first coating area t1, the second coating area t2, and the empty foil area t3 are sequentially adjacent to each other along the width direction Y of the main body 10. It is worth noting that multiple tabs 20 can be provided at intervals on the same side of the main body 10 in the width direction Y, or only one tab 20 can be provided on each side. The tabs 20 are arranged on one or both sides of the main body 10 in the width direction Y.

[0044] The edge of the tab 20 is formed by a top edge 21 and a side edge 22, with the two side edges 22 connected and distributed on both sides of the top edge 21 in the extending direction X. It is worth noting that the body 10 includes an end edge 11, which and the tab 20 are arranged on the same side of the body 10 in its width direction Y, and the end edge 11 intersects and connects with the side edges 22 of the tab 20. Understandably, the top edge 21 is located at the edge of the empty foil region t3, and the side edges 22 are partially located at the edge of the empty foil region t3 and partially located at the edge of the second coating region t2.

[0045] The top edge 21 is connected to the side edges 22 on both sides by the first arc edges 21a at both ends, and the first arc edges 21a and the side edges 22 intersect at the empty foil area t3. In practical applications, the top edge 21 and the side edges 22 can be formed by cutting along the same cutting trajectory or by cutting along different cutting trajectories. Since the two intersect at the empty foil area t3, the intersection is not coated with a coating, so burrs caused by coating collapse are less likely to occur. This can improve the edge cutting quality of the tab 20 and increase the yield of the electrode sheet 100.

[0046] The bending of the first arc edge 21a opposite to the main body 10 not only increases the configuration area of ​​the empty foil area t3 of the electrode tab 20 and improves the current carrying capacity of the electrode tab 20, but also reduces stress concentration and reduces the risk of edge folding of the electrode tab 20.

[0047] The angle θ2 between the tangents of the first arc edge 21a and the side edge 22 at the connection point refers to the angle between the tangents at the connection point within the projection plane perpendicular to the thickness direction of the main body 10. It is easy to understand that if θ2 is greater than 90°, in order for the first arc edge 21a to bend away from the main body 10, the side edge 22 needs to be set towards the inside of the tab 20, resulting in structural deformation of the tab 20. The two ends of the corner of the top edge 21 of the tab 20 will protrude, not only greatly limiting the area of ​​the tab 20 and severely reducing its current carrying capacity, but also increasing the risk of the tab 20 folding over. θ2 should also not be too small. If θ2 is too small, mechanical fluctuations and material fluctuations may cause cutting abnormalities at the intersection of the cutting trajectories, such as incomplete cutting, affecting the cutting efficiency of the electrode sheet 100. When 15°≤θ2<90°, the cutting efficiency of the tab 20 can be improved, while ensuring that the tab 20 has a large current carrying area, reducing the probability of the tab 20 folding over, and improving the reliability of the battery.

[0048] In summary, in the embodiments of this application, the top edge 21 and side edge 22 of the electrode 100 intersect at the empty foil area t3. Since no coating is applied at the intersection, burrs caused by coating collapse are less likely to occur, thus improving the edge cutting quality of the tab 20, increasing the yield of the electrode 100 and the reliability of the battery. Moreover, the top edge 21 is non-tangentially connected to the side edge 22 through its first arc edge 21a, and the included angle θ2 of the tangents satisfies the above-mentioned range. This not only improves the cutting efficiency of the tab 20 but also ensures that the tab 20 has a large current-carrying area, thereby improving battery performance.

[0049] Specifically, θ2 can take values ​​of 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 89°, and any values ​​between adjacent values.

[0050] In some embodiments, 20°≤θ2≤60°, which can further ensure the cutting efficiency and quality of the tab 20 and improve the reliability of the battery.

[0051] In some embodiments, the tabs 20 are symmetrically arranged in a plane along the vertical extension direction X.

[0052] The extension direction X of the main body 10 is perpendicular to its width direction Y. The symmetry plane of the tab 20 is parallel to its width direction Y and thickness direction (not shown). The tab 20 is symmetrically arranged, and its edge contour shape is symmetrical, which can greatly simplify the design of the cutting trajectory and reduce the design cost. Moreover, the symmetrical cutting path makes the stress distribution on both sides of the tab 20 completely consistent, avoiding defects such as warping, folding, and burrs caused by uneven stress on one side, thus improving the yield of the electrode sheet 100. In addition, the symmetrical structure of the tab 20 ensures uniform stress during the winding and stacking processes, effectively avoiding problems such as winding misalignment and uneven stacking of the tab 20 caused by asymmetry, reducing the risk of internal short circuits and uneven internal resistance in the battery, and improving battery reliability.

[0053] In other embodiments, the tab 20 may also be an asymmetric structure.

[0054] It is worth noting that the first arc edge 21a can be a segment of an arc edge that arches away from the main body 10, determined by a circle, hyperbola, parabola, cardioid, spiral, sine curve, cosine curve, cycloid, exponential function, logarithmic function, etc.

[0055] In some embodiments, refer to Figure 1 and Figure 2 The main body 10 includes an end edge 11 connected to the side edge 22. The end edge 11 is located at the edge of the first coating area t1 and is a straight edge.

[0056] The end edge 11 is designed as a straight edge, which simplifies the cutting path, reduces the difficulty of the cutting process, lowers the probability of burrs and other defects, and improves the cutting quality of the electrode sheet 100. As the edge connecting the main body 10 and the tab 20, the end edge 11 is designed as a straight edge. In the winding and stacking process, the end edge 11 helps to align the tab 20, avoids short circuits and abnormal internal resistance caused by misalignment of the tab 20, and improves the reliability of the battery.

[0057] In some embodiments, refer to Figures 1 to 4The top edge 21 includes an intermediate segment 21b connecting the two first arc edges 21a. The intermediate segment 21b serves to connect the two first arc edges 21a to form a complete top edge 21. The intermediate segment 21b can be constructed in various ways; for example, the intermediate segment 21b can be a combination of a straight line and an arc.

[0058] In a specific embodiment, the middle segment 21b is a curved edge, a straight edge, or an arc edge that is smoothly connected to the first arc edge 21a.

[0059] The curved edge can be wavy (e.g.) Figure 4 As shown), it can also be a segment of an arc-shaped edge that is 10 degrees away from the main body, determined by a circle, hyperbola, parabola, cardioid, spiral, sine curve, cosine curve, cycloid, exponential function, logarithmic function, etc. Figure 1 (As shown).

[0060] When the middle segment 21b is an arc edge, it is smoothly connected to the first arc edge 21a to avoid forming sharp corners, thereby reducing the probability of burr generation and improving the cutting quality of the tab 20. Alternatively, the first arc edge 21a and the middle segment 21b can be located on the same circular arc or elliptical arc to simplify the cutting trajectory design of the middle segment 21b.

[0061] When the middle segment 21b is a straight edge (e.g.) Figure 3 As shown in the figure, the cutting path design is simpler and can be shortened, thereby improving cutting efficiency. When the middle segment 21b is a straight edge, it can be parallel to the end edge 11 or inclined relative to the end edge 11.

[0062] In some embodiments, the middle segment 21b is a straight edge, the first arc edge 21a has a heat-affected zone, and the middle segment 21b does not have a heat-affected zone.

[0063] The heat-affected zone (HAZ) is the area in which the material's microstructure and mechanical properties change due to heat (but not melting) during welding or hot cutting. The most direct way to determine the presence of a HAZ is by observing the presence of a discolored area; its presence usually indicates the existence of a HAZ. The presence of a HAZ can also be determined by observing the microstructure near the cut surface using a metallographic microscope. If the metallographic structure of the cut surface differs from that of the base material, a HAZ can be identified. Additionally, hardness testing can be used to determine the presence of a HAZ; the hardness of the HAZ is higher than that of the base material.

[0064] The first arc edge 21a is formed by hot working and has a heat-affected zone, while the middle section 21b is formed by cold working and does not have a heat-affected zone. Figure 8It is understood that the first arc edge 21a can be formed by laser-cutting the foil area T2 of the bare electrode 100A, and the middle section 21b can be formed by the outer edge T21 of the foil area T2, which is usually formed by cold processing of metal cutting. In practical applications, after the laser cutting device cuts the empty foil area t3 along the cutting trajectory corresponding to the first arc edge 21a on one side, it moves outside the range of the bare electrode 100A and moves along the idle running trajectory, and then moves again to the cutting trajectory corresponding to the first arc edge 21a on the other side. The outer edge T21 corresponding to the idle running trajectory travel forms the straight middle section 21b connecting the two first arc edges 21a.

[0065] At this time, since the empty running trajectory does not pass through the bare electrode 100A, its trajectory shape and speed will not affect the cutting quality of the tab 20. This not only simplifies the design but also helps to shorten the cutting time and improve the cutting efficiency.

[0066] In some embodiments, the middle section 21b is a straight edge, and the surface roughness of the first arc edge 21a is less than the surface roughness of the middle section 21b.

[0067] Understandably, the tab 20 includes two large surfaces located in the thickness direction of the body 10, and a cross-section connecting the two large surfaces. The end face roughness of the intermediate section 21b refers to the roughness of the cross-section located in the intermediate section 21b. The end face roughness of the first arc edge 21a refers to the roughness of the cross-section located in the first arc edge 21a.

[0068] The roughness of the end face of the middle section 21b is greater than that of the end face of the first arc edge 21a, indicating that the cut surface of the middle section 21b is rougher than that of the first arc edge 21a. In practical applications, the middle section 21b is formed through the outer edge T21 of the bare electrode sheet 100A foil area T2, which is the retained edge of the original foil material. It is generally obtained by one-time punching or laser rapid cutting. The cut surface texture is coarse and may have slight stripes, burrs, etc., with a relatively large roughness. It does not affect the current flow of the tab 20 or the electrical connection with the pole or adapter plate. The first arc edge 21a is cut using precision equipment (such as laser cutting equipment, ultrasonic cutting equipment, die-cutting equipment), which has higher cutting accuracy and smoothness, smaller cut surface roughness, and smoother cut surface. It can reduce stress concentration and avoid cracking and folding in the corner area of ​​the top edge 21 of the tab 20.

[0069] Since the middle section 21b can be formed from the outer edge T21 of the original foil area T2, the cutting path can be shortened, the cutting efficiency can be improved, and the cost can be reduced.

[0070] In some embodiments, refer to Figures 1 to 4 Each side edge 22 includes a side inclined edge 22c connected to the first arc edge 21a, and each side inclined edge 22c is inclined toward the other side edge 22 in a direction pointing toward the top edge 21.

[0071] It is easy to understand that the beveled edges 22c of the two side edges 22 slope towards the side where the top edge 21 is located, causing the width of the tab 20 to gradually narrow towards the top edge 21. On the one hand, this makes the connection between the side edge 22 and the first arc edge 21a smoother, reducing the sharpness of the corners at their interaction, thereby reducing the generation of burrs and other defective structures and improving the cutting quality of the electrode sheet 100. On the other hand, the gradually narrowing tab 20 reduces the probability of contact with the separator or housing 1200 during winding and assembly, improving the reliability of the battery. In addition, the beveled edges 22c are straight edges, which simplifies the cutting path of the side edges 22 and improves cutting efficiency.

[0072] In a further embodiment, refer to Figures 1 to 4 Each side edge 22 also includes a second arc edge 22d, which transitions between the end edge 11 and the side bevel 22c, and the second arc edges 22d of the two side edges 22 bend toward each other.

[0073] It is easy to understand that the second arc edge 22d is recessed to transition between the side bevel edge 22c and the end edge 11.

[0074] The plane containing end edge 11 is the boundary plane between the first coating region t1 and the second coating region t2, and the connection area between side edge 22 and end edge 11 is located within this boundary plane. If end edge 11 is directly connected to side bevel 22c, a sharp corner is easily formed at the intersection, which is prone to burrs due to coating collapse. Therefore, each side edge 22 is connected to side bevel 22c and end edge 11 through a second arc edge 22d, which helps to reduce burr generation and improve battery reliability.

[0075] Can the second arc edge 22d be tangentially connected to the side bevel edge 22c, and the second arc edge 22d be tangentially connected to the end edge 11, so as to smoothly connect the end edge 11 and the side bevel edge 22c, improve the smoothness of the corresponding cutting trajectory of the side edge 22, and improve the cutting quality.

[0076] In some embodiments, refer to Figures 1 to 4 The second arc edge 22d and the side bevel edge 22c connect at the empty foil area t3. The connection point of the first arc edge 21a and the side bevel edge 22c is located in the uncoated empty foil area t3, which can reduce burrs caused by coating collapse at the connection point and improve the cutting quality.

[0077] In other embodiments, the second arc edge 22d and the side bevel edge 22c may also be connected to the second coating area t2.

[0078] In some embodiments, refer to Figure 2Each side edge 22 intersects the corresponding first arc edge 21a at position p. The first boundary line I1 between the second coating area t2 and the empty foil area t3 intersects the side edge 22 at position A. The position of the top edge 21 furthest from the body 10 along the width direction Y is position b. The inclination angle of the side inclined edge 22c is θ1. Along the width direction Y of the body 10, the distance between position p and position b is L2, the distance between position b and position A is L3, and the protrusion dimension of the electrode tab 20 along the width direction Y is L4. The electrode 100 satisfies at least one of the following conditions: 1 / 8 < L2 / L3 < 1; 1mm≤L4-L3≤5mm; and, 0°<θ1≤15°.

[0079] When the tab 20 has a symmetrical structure, L2 represents the space occupied by the top edge 21 in the width direction Y of the main body 10, and L3 represents the dimension of the empty foil area t3 in the width direction Y of the main body 10. When the tab 20 has an asymmetrical structure, L2 and L3 refer to the distance between positions p and b on the same side edge 22 and the distance between positions b and A, respectively.

[0080] L2 / L3 represents the proportion of the empty foil area t3 located at the top edge 21 along the width direction Y relative to the entire empty foil area t3. If L2 / L3 is too small, the size of the top edge 21 in the width direction Y is too small, and the extension of the top edge 21 is too gentle. This can easily lead to sharp angles at the connection points with the side edges 22, causing burrs and other structural defects. L2 ≠ L3; otherwise, the space of the side edges 22 is squeezed, resulting in a limited area of ​​the empty foil area t3, which is detrimental to the flow capacity of the tab 20. When 1 / 8 < L2 / L3 < 1, the area of ​​the empty foil area t3 is appropriate, ensuring the flow capacity of the tab 20 and reducing the sharp angles at the connection points between the top edge 21 and the side edges 22, thus improving cutting quality. Specifically, L2 / L3 can take values ​​of 1 / 4, 3 / 8, 1 / 2, 5 / 8, 3 / 4, 7 / 8, and any values ​​between adjacent values. Yes, 1 / 5 < L2 / L3 < 4 / 5. In this case, the configuration ratio of the side edge 22 and the top edge 21 along the width direction Y is reasonable, which helps to ensure the cutting quality and take into account the flow capacity.

[0081] L4 is determined by the maximum distance along the width direction Y between the end edge 11 and position b. L4-L3 refers to the dimension along the width direction Y between position A and end edge 11. During actual cutting, the first boundary line I1 where position A is located is the boundary line between the coating area T1 and the foil area T2 on the bare electrode 100A. End edge 11 corresponds to the cutting trajectory of the cutting device in the coating area T1. If L4-L3 is too small, the cutting position of the coating area T1 is too close to the first boundary line I1, and it is easy to cut into the foil area T2 due to mechanical fluctuations and incoming material fluctuations, resulting in cutting abnormalities. If L4-L3 is too large, the area of ​​the coating area T1 that is cut off is too large, resulting in waste of coating material and reducing battery energy density. When 1mm≤L4-L3≤5mm, cutting abnormalities can be avoided, coating utilization can be improved, and battery energy density can be improved. Specifically, L4-L3 can take values ​​of 1mm, 2mm, 3mm, 4mm, 5mm, and any values ​​between adjacent values.

[0082] θ1 refers to the tilt angle of the side slope 22c relative to the width direction Y. θ1 should not be too large, otherwise the tilt angle of the side slope 22c will be too large, compressing the area of ​​the empty foil region t3, resulting in insufficient current-carrying area of ​​the tab 20, severely limiting the width of the tab 20, reducing the strength of the tab 20, and making the tab 20 prone to folding. When 0° < θ1 ≤ 15°, the current-carrying area and structural strength of the tab 20 can be guaranteed, reducing the risk of tab 20 folding and improving battery performance. Specifically, θ1 can take values ​​of 1°, 3°, 5°, 8°, 10°, 12°, 15°, and any values ​​between adjacent values.

[0083] In some embodiments, refer to Figure 3 and Figure 4 The first coating region t1 and the second coating region t2 are electrode material coating regions t01 with the same material.

[0084] Specifically, electrode 100 can serve as a negative electrode, with the electrode material on it being a negative electrode material. The lithium intercalation capability at the edge of the negative electrode is enhanced by increasing the second coating region t2 of the tab 20, thereby improving edge lithium deposition.

[0085] In some embodiments, refer to Figure 1 The first coating region t1 includes a first sub-region t11 and a second sub-region t12 arranged adjacent to each other along the width direction Y. The first sub-region t11 is an electrode material coating region t01. The second sub-region t12 and the second coating region t2 are adjacent to each other and are both insulating material coating regions t02 of the same material.

[0086] In some cases, the coating region T1 of the bare electrode 100A includes an electrode material coating region t01 and an insulating material coating region t02 adjacent to each other along its width direction Y. During laser cutting, the electrode material coating region t02 is passed through, such that a portion of the insulating material coating region t02 is located on the tab 20 to form a second coating region t2, and a portion is located on the body 10 and forms an end edge 11 as a second sub-region t12.

[0087] At this time, the electrode 100 can be a positive electrode. The coating material of the coating area at the root of the tab 20 and the coating area of ​​the body 10 near the edge of the tab 20 is an insulating material, which can reduce the amount of lithium depletion in the edge area of ​​the positive electrode, thereby improving the edge lithium plating problem of the negative electrode that is matched with it.

[0088] In one specific embodiment of this application, the electrode 100 includes a main body 10 and an electrode tab 20. The electrode tab 20 has a symmetrical structure. The main body 10 includes a first coating area t1, and the electrode tab 20 includes the aforementioned second coating area t2 and an empty foil area t3. The top edge 21 of the electrode tab 20 includes a first arc edge 21a and a middle section 21b, where the middle section 21b is a straight edge connected to the first arc edge 21a. The side edge 22 includes the aforementioned side bevel 22c and a second arc edge 22d. The side bevel 22c is not tangentially connected to the first arc edge 21a, and the included angle between the tangents is θ2, where 15°≤θ2<90°. The inclination angle of the side bevel 22c is θ1, where 0°<θ1≤15°. The second arc edge 22d tangentially connects the side bevel 22c and the end edge 11 of the main body 10. The middle section 21b and the end edge 11 are parallel straight edges.

[0089] Additionally, refer to Figure 5 and Figure 6 The method for preparing electrode 100 in this application embodiment includes: S10. Call the laser cutting device to perform the electrode tab 20 cutting operation on the bare electrode sheet 100A located in its working plane along the set trajectory G, so as to process the bare electrode sheet 100A into an electrode sheet 100 with electrode tab 20.

[0090] The set trajectory G is located in the xy-plane coordinate system determined by the working plane. The bare electrode 100A includes a foil area T2 and a coating area T1 arranged adjacently along the y-axis, and the foil area T2 and the coating area T1 are arranged longitudinally along the x-axis. The foil area T2 includes an outer edge T21 that is away from the coating area T1. The set trajectory G includes a first trajectory G1 that passes through the foil area T2 to form the top edge 21 of the electrode 100 and a second trajectory G2 that passes through the coating area T1 and the foil area T2 to form the side edge 22 of the electrode 100. The first trajectory G1 includes a first arcuate trajectory segment G11 located in the foil area T2. The first arcuate trajectory segment G11 intersects the second trajectory G2 in the foil area T2. The first arcuate trajectory segment G11 bends toward the side away from the coating area T1, and the angle between the tangent of the first arcuate trajectory segment G11 and the second trajectory G2 at the connection point is θ2', where 15°≤θ2'<90°.

[0091] Understandably, the coating region T1 of the bare electrode 100A is coated with coating material, while its foil region T2 is not coated with coating material. Both the coating region T1 and the foil region T2 extend along the x-axis. The foil region T2 is used to form the empty foil region t3 of the tab 20. The coating region T1 is used to form the first coating region t1 and the second coating region t2 of the electrode 100.

[0092] The laser cutting apparatus has at least one laser cutter. The first trajectory G1 and the second trajectory G2 can be the cutting trajectories of the same laser cutter or the cutting trajectories of different laser cutters.

[0093] The working plane of a laser cutting device is usually horizontal. Specifically, the laser cutting device is equipped with a support device for supporting the bare electrode 100A. For ease of understanding, the support surface where the bare electrode 100A is located can be regarded as the working plane of the laser cutting device.

[0094] In practical applications, when the laser cutter of the laser cutting device moves along the first trajectory G1, it can cut the top edge 21 of the tab 20 on the bare electrode sheet 100A, and when it moves along the second trajectory G2, it can cut the side edge 22 of the tab 20 on the bare electrode sheet 100A.

[0095] The first trajectory G1 includes a first arc-shaped trajectory segment G11 that intersects the second trajectory G2 in the foil area T2, and the tangent angle θ2' at the intersection of the first arc-shaped trajectory segment G11 and the second trajectory G2 is equal to the tangent angle θ2 of the first arc edge 21a and the side edge 22 mentioned above. Thus, an electrode sheet 100 with the aforementioned first arc edge 21a and side edge 22 is cut from the bare electrode sheet 100A.

[0096] As described above, if θ2' is greater than 90°, in order for the first arc-shaped trajectory segment G11 to bend with the first arc edge 21a away from the coating area T1, the second trajectory G2 needs to be set towards the inside of the tab 20. This results in deformation of the tab 20 structure, with the two ends of the top edge 21 of the tab 20 protruding, and the area of ​​the tab 20 greatly reduced, leading to insufficient current carrying capacity and increasing the risk of the tab 20 folding over. θ2' should also not be too small. If θ2' is too small, mechanical fluctuations and material fluctuations may cause cutting abnormalities at the junction, such as incomplete cutting, affecting the cutting efficiency of the electrode sheet 100. When 15°≤θ2'<90°, the cutting efficiency of the tab 20 can be improved, while ensuring that the tab 20 has a large current carrying area, reducing the probability of the tab 20 folding over, and improving the reliability of the battery.

[0097] Specifically, θ2' can take values ​​of 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 89°, and any values ​​between adjacent values.

[0098] In some embodiments, 20°≤θ2'≤60°, which can further ensure the cutting efficiency and quality of the tab 20 and improve the reliability of the battery.

[0099] The first arc-shaped trajectory segment G11 can be an arc-shaped trajectory determined by a circle, hyperbola, parabola, cardioid, spiral, sine curve, cosine curve, cycloid, exponential function, logarithmic function, etc.

[0100] The electrode 100 fabrication method, because its first trajectory G1 and second trajectory G2 intersect at the foil region T2 of the bare electrode 100A, and since the intersection is not coated, coating collapse is less likely to occur during cutting, thereby reducing the probability of burr formation, improving the edge cutting quality of the tab 20, and enhancing the yield of the electrode 100 and the reliability of the battery. Furthermore, the first trajectory G1 includes a first arc-shaped trajectory segment G11 forming the first arc edge 21a. The first arc-shaped trajectory segment G11 is non-tangentially connected to the second trajectory G2, and the included angle θ2' of the tangents satisfies the aforementioned range. This not only improves the cutting efficiency of the tab 20 but also ensures that the tab 20 has a large current-carrying area, improving battery performance. In addition, using laser cutting technology to cut the tab 20 on the bare electrode 100A not only results in high cutting quality but also high cutting efficiency, contributing to improved battery reliability.

[0101] In some embodiments, refer to Figure 6 and Figure 8 It is understood that the first trajectory G1 includes two first arc-shaped trajectory segments G11 arranged at intervals along the x-axis, and an intermediate trajectory segment G12 connecting the two first arc-shaped trajectory segments G11.

[0102] The intermediate trajectory segment G12 connects between the first arc-shaped trajectory segments G11 at both ends to form a complete first trajectory G1, which in turn cuts to obtain the top edge 21 of the tab 20. The intermediate trajectory segment G12 is used to form the intermediate segment 21b of the tab 20, and the intermediate segment 21b connects the first arc edges 21a on both sides of the top edge 21 of the tab 20.

[0103] In one specific embodiment, the intermediate trajectory segment G12 is located in the foil area T2 and is either straight or curved. Specifically, when the intermediate trajectory segment G12 is straight, it is typically a straight line parallel to the x-axis. When the intermediate trajectory segment G12 is curved, it can be a wavy curve, an arc curve, etc. In this case, the intermediate trajectory segment G12 is obtained by laser cutting the foil area T2, resulting in an intermediate segment 21b with high edge quality, thus improving the overall cutting quality of the top edge 21. In particular, when the intermediate trajectory segment G12 is straight, the cutting trajectory length can be shortened, improving cutting efficiency.

[0104] In another specific embodiment, such as Figure 7 As shown, the intermediate trajectory segment G12 is located outside the range of the bare electrode sheet 100A. That is, the intermediate trajectory segment G12 serves as an idle trajectory, connecting the first arc-shaped trajectory segments G11 on both sides, greatly improving the cutting efficiency. At this time, the intermediate segment 21b of the top edge 21 of the electrode tab 20 is straight and is cold-formed without a heat-affected zone, while the first arc edge 21a is laser-processed and has a heat-affected zone.

[0105] In another specific embodiment, such as Figure 6 As shown, the intermediate trajectory segment G12 is located in the foil area T2 and is an arc-shaped trajectory that smoothly connects with each of the first arc-shaped trajectory segments G11. At this time, the intermediate trajectory segment G12 passes through the foil area T2 and is an arc-shaped trajectory, smoothly connecting between the two first arc-shaped trajectory segments G11. Since the intermediate trajectory segment G12 is an arc-shaped trajectory, and the middle segment 21b of the top edge 21 is an arc-shaped edge, which smoothly connects with the first arc edges 21a on both sides of the top edge 21, the risk of abnormal cutting is greatly reduced and the cutting quality is improved.

[0106] It is worth noting that when the intermediate trajectory segment G12 is an arc-shaped trajectory, it bends on the side away from the coating area T1.

[0107] In some embodiments, the reference Figure 6 and Figure 8 The second trajectory G2 includes sub-trajectories G21. Each sub-trajectories G21 includes an end-edge trajectory G21c located in the coating region T1 to form the end edge 11 of the electrode 100, and a side-edge trajectory G21d passing through the coating region T1 and the foil region T2 to form the side edge 22. Each side-edge trajectory G21d independently intersects a first arcuate trajectory segment G11 in the foil region T2. ​​The end-edge trajectory G21c is located on the side of the side-edge trajectory G21d away from the first arcuate trajectory. Each first trajectory G1 intersects with two sub-trajectories G21, and the two sub-trajectories G21 are discontinuously arranged along the x-axis.

[0108] Understandably, the side edge trajectory G21d of each sub-trajectory G21 intersects with the first trajectory G1 in the empty foil region t3. Since the end edge trajectory G21c is used to form the end edge 11 of the electrode body 100, and the end edge 11 is usually a straight edge, the end edge trajectory G21c usually includes a straight line trajectory for forming the end edge 11.

[0109] At this point, dividing the second trajectory G2 into two discontinuous sub-trajectories G21, each sub-trajectories G21 corresponding to the side edge 22 and end edge 11 on one side of the tab 20, can simplify the path of the second trajectory G2 and speed up the cutting efficiency.

[0110] Each sub-trajectory G21 can serve as the cutting trajectory of the same laser cutter or as the cutting trajectory of different laser cutters.

[0111] Specifically, in the embodiments, refer to... Figure 6 and Figure 8 The laser cutting device moves along the set trajectory G towards the positive x-axis. Each side edge trajectory G21d includes an inclined trajectory segment d1, and each inclined trajectory segment d1 intersects with the corresponding first arc-shaped trajectory segment G11 in the foil area T2, and extends inclinedly towards the positive x-axis along the cutting direction of the laser cutting device.

[0112] In practical applications, among the two second inclined trajectory segments d1 connected to the same first trajectory G1, the second inclined trajectory segment d1 on the left travels towards the positive y-axis and extends inclined towards the positive x-axis. The second inclined trajectory segment d1 on the right travels towards the negative y-axis and extends inclined towards the positive x-axis. Overall, the two second inclined trajectory segments d1 of the same electrode 20 are inclined towards each other in the positive y-axis direction, thus obtaining the two aforementioned side inclined sides 22c of the same electrode 20.

[0113] The inclined trajectory segment d1 simplifies the path of the side edge trajectory G21d, improving cutting efficiency. The electrode tab 20 with the aforementioned side bevel 22c is obtained through the inclined trajectory segment d1. The side bevel 22c allows the width of the electrode tab 20 to gradually narrow towards the top edge 21. On one hand, the connection between the side edge 22 and the first arc edge 21a is smoother, reducing the generation or sharpness of sharp corners, thereby reducing the generation of burrs and other defective structures, and improving the processing quality of the electrode sheet 100. On the other hand, the gradually narrowing width of the electrode tab 20 reduces the probability of contact with the separator or casing 1200 during winding and assembly, improving battery reliability.

[0114] In one embodiment, reference is made to Figure 7 The angle of inclination for each inclined trajectory segment d1 is θ1', where 0° < θ1' ≤ 15°.

[0115] The tilt angle θ1' of the tilted trajectory segment d1 is equal to the tilt angle θ1 of the formed side slope 22c. Referring to the above description, θ1' should not be too large; otherwise, the tilt angle of the side slope 22c will be too large, compressing the area of ​​the empty foil region t3 and resulting in insufficient current-carrying area of ​​the tab 20. It will also severely restrict the width of the tab 20, reduce its strength, and make it prone to folding. When 0° < θ1' ≤ 15°, the current-carrying area and structural strength of the tab 20 can be guaranteed, reducing the risk of folding and improving battery performance. Specifically, θ1' can take values ​​of 1°, 3°, 5°, 8°, 10°, 12°, 15°, and any values ​​between adjacent settings.

[0116] Further in the embodiments, refer to Figure 6 and Figure 8 Each side edge 22 also includes a second arcuate trajectory segment d2. In the same sub-trajectory G21, the end edge trajectory G21c, the second arcuate trajectory segment d2, and the inclined trajectory segment d1 are connected sequentially along the x-axis. The second arcuate trajectory segments d2 of the two side edge trajectories G21d that intersect with the same first trajectory G1 bend toward each other.

[0117] Specifically, the second arc-shaped trajectory segment d2 is used to form the second arc edge 22d of the side edge 22 of the tab 20.

[0118] At this point, by connecting the end edge trajectory G21c and the inclined trajectory segment d1 through the second arc-shaped trajectory segment d2, the smoothness of the sub-trajectory G21 is improved, the curvature abrupt change at the junction of the side edge trajectory G21d and the end edge trajectory G21c is reduced, and the processing quality of the electrode 100 is improved.

[0119] In some embodiments, refer to Figure 7 The projection of the boundary line between the coating area T1 and the foil area T2 onto the xy-plane coordinate system is taken as the first reference line F1. The foil area T2 includes an outer edge T21 that is away from the coating area T1. The projection of the outer edge T21 onto the xy-plane coordinate system is taken as the second reference line F2. The position where the first arc-shaped trajectory segment G11 intersects with the second trajectory G2 is position p'. The position where the first trajectory G1 is farthest from the coating area T1 is position b'. The position where the second trajectory G2 intersects with the first reference line F1 is position A'. The distance between position b' and position A' along the y-axis is L3'. The minimum distance between each first trajectory G1 and the second reference line F2 is L1'. The maximum distance between the second trajectory G2 and the second reference line F2 is L'. The farthest distance between position b' and the second trajectory G2 along the y-axis is L4', satisfying: 1 / 8 < L2' / L3' < 1; 1mm≤L4'-L3'≤5mm; and / or 1 / 8≤L1' / L'≤7 / 8.

[0120] Among them, the position p' corresponds to the position p in the previous text, the position A' corresponds to the position A in the previous text, the position b' corresponds to the position b in the previous text, the size L2' corresponds to L2 in the previous text and is equal to it, the size L3' corresponds to L3 in the previous text and is equal to it, and the size L4' corresponds to L4 in the previous text and is equal to it.

[0121] As described above, when 1 / 8 < L2' / L3' < 1, the area t3 of the empty foil region of the tab 20 is appropriately sized, ensuring the current-carrying capacity of the tab 20 and reducing the sharp angle at the connection between the top edge 21 and the side edge 22 of the tab 20, thus improving the cutting quality. Specifically, L2' / L3' can take values ​​of 1 / 4, 3 / 8, 1 / 2, 5 / 8, 3 / 4, 7 / 8, and any values ​​between adjacent values. Alternatively, 1 / 5 < L2' / L3' < 4 / 5. In this case, the configuration ratio of the side edge 22 and the top edge 21 of the tab 20 along the y-axis is reasonable, which helps to ensure cutting quality while also considering current-carrying capacity.

[0122] As mentioned above, when 1mm ≤ L4' - L3' ≤ 5mm, it can both avoid cutting abnormalities and improve coating utilization, thereby increasing battery energy density. Specifically, L4' - L3' can take values ​​of 1mm, 2mm, 3mm, 4mm, 5mm, and any values ​​between adjacent values.

[0123] L1' represents the minimum distance between the first trajectory G1 and the outer edge T21. L' represents the maximum distance between the end edge trajectory G21c of the second trajectory G2 and the outer edge T21. L'-L1' represents the protruding length of the tab 20 obtained by cutting. If L1' / L' is too small, it means that the larger L'-L1' is, the longer the protruding length of the tab 20 is, the lower the structural strength of the tab 20, and the easier it is to bend. Moreover, if L1' is too small, the first trajectory G1 is too close to the outer edge T21 of the foil area T2, which can easily lead to cutting abnormalities due to mechanical fluctuations or incoming material fluctuations, thus reducing the cutting quality. If L1' / L' is too large, the protruding length of the tab 20 is too small, resulting in serious material waste, and the current-carrying area of ​​the tab 20 is seriously insufficient, which is not conducive to battery performance. When 1 / 8 ≤ L1' / L' ≤ 7 / 8, it balances the structural strength and current-carrying area of ​​tab 20, reduces the risk of electrode 100 folding and cutting abnormalities, improves the material utilization rate of bare electrode 100A, reduces production costs, and improves battery performance. Specifically, L1' / L' can take values ​​of 1 / 4, 3 / 8, 1 / 2, 5 / 8, 3 / 4, 7 / 8, and any values ​​between adjacent values. Alternatively, 1 / 5 ≤ L1' / L' ≤ 1 / 3, which effectively reduces the risk of cutting abnormalities while balancing the current-carrying capacity and structural strength of tab 20, ensuring battery performance.

[0124] In some embodiments, invoking a laser cutting device to perform a tab cutting 20 operation on a bare electrode sheet 100A located in its working plane along a predetermined trajectory G includes: The first and second laser cutters of the laser cutting device are invoked to perform the tab cutting 20 operation on the bare electrode sheet 100A located in the working plane of the laser cutting device along the first trajectory G1 and the second trajectory G2 towards the positive x-axis, respectively.

[0125] The positive direction of the x-axis is not limited to the left-to-right direction mentioned above. The emphasis here is on expressing that the first and second laser cutters travel along the x-axis toward the same side along their respective cutting trajectories.

[0126] At this time, by using different laser cutters to perform the electrode tab 20 cutting operation according to the first trajectory G1 and the second trajectory G2 respectively, the cutting efficiency can be accelerated and the production efficiency of electrode 100 can be improved.

[0127] In some embodiments, refer to Figure 9 and Figure 10 The trajectory G is set to include multiple second trajectories G2 and multiple first trajectories G1 that are spaced apart along the x-axis, so as to cut multiple tabs 20 at intervals along the x-axis on the same bare electrode sheet 100A, thereby improving the cutting efficiency of the tabs 20.

[0128] In one specific embodiment, reference is made to Figure 9 At least in a portion of the second trajectory G2, among the two sub-trajectories G21, the two end edge trajectories G21c are connected and located between the two side edge trajectories G21d. In every two adjacent second trajectories G22, the two opposing sub-trajectories G21 intersect the same first trajectory G1.

[0129] That is, the edge trajectories G21c of the two sub-trajectories G21 belonging to the same second trajectory G2 are connected, making the second trajectory G2 roughly U-shaped, reducing the number of times its laser emission is started and stopped, and simplifying the control of the second laser cutter. Moreover, the edge trajectories G21c of the two sub-trajectories G21 are set continuously (usually continuously along a straight line), avoiding sharp corners formed by trajectory changes, and improving the cutting quality of the edge 11 of the electrode 100.

[0130] It is worth noting that the two sub-trajectories G21 of the second trajectory G2 can be connected via the end edge trajectory G21c. Later, the sub-trajectories G21 near the two ends of the bare electrode 100Ax axis can be cut off by slitting. Alternatively, the edges at both ends of the bare electrode 100Ax axis can be cut along different sub-trajectories G21, and each can be matched with a complete second trajectory G2 to intersect with the same first trajectory G1, cutting out the same tab 20, thereby improving the utilization rate of the areas at both ends of the bare electrode 100A.

[0131] In other embodiments, each second trajectory G2 includes two sub-trajectories G21 that intersect with the same first trajectory G1 and are discontinuously arranged along the x-axis. In every two adjacent second trajectories G2, the end edge trajectories G21c of the two opposing sub-trajectories G21 intersect. In this way, each second trajectory G2, in conjunction with a first trajectory G1, can be cut to obtain an electrode tab 20, avoiding the situation where a certain sub-trajectories G21 exist independently and cannot cooperate with another sub-trajectories G21 to form the same electrode tab 20, thereby improving the material utilization rate of the bare electrode sheet 100A.

[0132] In some embodiments, refer to Figure 10 The trajectory G also includes a third trajectory G3 and a plurality of first trajectories G1 arranged at intervals along the x-axis. The multi-component trajectories G21 are arranged at intervals along the x-axis, each component trajectory G21 intersecting with the same first trajectory G1. In every two adjacent groups of component trajectories G21, the edge trajectories G21c of the two closest component trajectories G21 are connected via the third trajectory G3. In practical applications, the third trajectory G3 and the edge trajectories G21c together form the edge 11 of the electrode 100.

[0133] The sub-trajectories G21 in each group, the sub-trajectories G21 located on the same side as the first trajectory G1 are called the first sub-trajectories G21A, and the sub-trajectories G21 on the other side are called the second sub-trajectories G21B.

[0134] Accordingly, step S10, which involves calling a laser cutting device to perform the tab cutting 20 operation on the bare electrode sheet 100A located in its working plane along a set trajectory G, includes: Multiple laser cutters of the laser cutting device are invoked to perform electrode tab cutting 20 operations on the bare electrode sheet 100A located in the working plane of the laser cutting device, respectively, along the first sub-track G21A, the first track G1, the second sub-track G21B and the third track G3 in the positive direction of the x-axis.

[0135] At this point, further subdividing the set trajectory G and using multiple laser cutters (specifically, four laser cutters) to perform cutting operations according to the corresponding trajectory can greatly improve cutting efficiency.

[0136] In some embodiments, combined with Figure 6 It is understood that the coating region T1 includes an electrode material coating region t01 and an insulating material coating region t02 arranged adjacently along the y-axis, and the insulating material coating region t02 and the foil region T2 are adjacent to each other. The second trajectory G2 is located outside the range of the electrode material coating region t01 and passes through the insulating material coating region t02.

[0137] In practical applications, the cutting light of the laser cutter passes through the insulating material coating area t02, so that part of the insulating material coating area t02 is located at the tab 20 to form the second coating area t2, and part is located at the main body 10 to form the end edge 11 as the aforementioned second sub-area t12.

[0138] At this time, the electrode 100 can be a positive electrode. The coating material of the coating area T1 at the root of the tab 20 and the coating area T1 of the body 10 near the edge of the tab 20 is an insulating material, which can reduce the amount of lithium depletion in the edge area of ​​the positive electrode 100, thereby improving the edge lithium plating problem of the negative electrode that is matched with it.

[0139] In another embodiment, combined Figure 8 It is understood that coating region T1 is electrode material coating region t01, and the second trajectory G2 passes through electrode material coating region t01. Specifically, electrode 100 can be used as a negative electrode, and the electrode material on it is a negative electrode material. At this time, an electrode material coating region t01 is provided at the root of the tab 20, which expands the lithium intercalation capability of the edge of the negative electrode 100 and improves its edge lithium deposition.

[0140] In addition, this application also provides an electrode 100 preparation apparatus, including a laser cutting device and a control device. The control device is connected to the laser cutting device and is used to control the operation of the laser cutting device according to the substrate preparation method in the above embodiments. This electrode 100 preparation apparatus has all the beneficial effects of the above embodiments.

[0141] In addition, this application also provides a battery cell 1000, including the electrode 100 in the above embodiments. The battery cell 1000 is the smallest unit for electrochemical reactions and can be a secondary battery or a primary battery. The battery cell 1000 includes an electrode assembly 1100, which typically includes a positive electrode, a negative electrode, and a separator separating the positive and negative electrodes. The positive and negative electrodes can be the electrode 100 in the embodiments of this application. The electrode assembly 1100 can be a stacked structure or a wound structure.

[0142] In some embodiments, combined with Figure 11 and Figure 12It is understood that the battery cell 1000 also includes a housing 1200 and a top cover assembly 1300. The housing 1200 and the top cover assembly 1300 together form an internal space for accommodating the electrode assembly 1100. Specifically, the housing 1200 may have a receiving cavity formed therein, with at least one end open. The top cover assembly 1300 closes to the open end of the housing 1200 to seal the receiving cavity, and the electrode assembly 1100 is mounted within the receiving cavity. The housing 1200 may be, but is not limited to, a metal housing, such as an aluminum housing or a steel housing. An electrolyte may be injected into the battery cell 1000. The electrolyte wets the interior of the electrode assembly 1100, providing an ion migration pathway for the electrochemical reaction of the electrode assembly 1100 and serving a conductive function.

[0143] In addition, this application also provides an electrical device, including the aforementioned battery cell 1000. The battery cell 1000 provides electrical energy to the electrical device. The electrical device can be, but is not limited to, a mobile phone, tablet, laptop, electric toy, power tool, electric vehicle, electric car, ship, etc. Taking a vehicle 10000 as an example, if the electrical device is... Figure 13 As shown. The battery cell 1000 can be located at the rear, front, or bottom of the vehicle 10000. The battery cell 1000 can provide power for the drive of the vehicle 10000 and also for the control system of the vehicle 10000.

[0144] It should be noted that the related technologies mentioned in this application do not constitute prior art, but are only used to enhance the understanding of the content disclosed in this application.

[0145] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0146] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An electrode (100), characterized in that, include: The main body (10) includes a first coating area (t1); A tab (20) protrudes from one side of the main body (10) along the width direction (Y). The tab (20) includes a second coating area (t2) and an empty foil area (t3). The first coating area (t1), the second coating area (t2) and the empty foil area (t3) are sequentially adjacent to each other along the width direction (Y). The electrode (20) includes a top edge (21) and side edges (22) arranged on both sides of the top edge (21) along the extension direction (X) of the body (10). The top edge (21) and the body (10) are arranged on opposite sides of the side edges (22) in the width direction (Y). The top edge (21) includes first arc edges (21b) located at both ends thereof. The first arc edges (21b) are connected to the side edges (22) and are curved away from the body (10). The angle between the tangents at the connection point of the first arc edge (21b) and the side edge (22) is θ2, where 15°≤θ2<90°.

2. The electrode (100) according to claim 1, characterized in that, 20°≤θ2≤60°; and / or, The tabs (20) are symmetrically arranged along a plane perpendicular to the extension direction (X); and / or, The main body (10) includes an end edge (11) connected to the side edge (22), the end edge (11) being located at the edge of the first coating area (t1), and the end edge (11) being a straight edge.

3. The electrode (100) according to claim 1, characterized in that, The top edge (21) includes an intermediate segment (21a) connecting the two first arc edges (21b), the intermediate segment (21a) being a curved edge, a straight edge, or an arc edge that is smoothly connected to the first arc edge (21b).

4. The electrode (100) according to claim 3, characterized in that, The middle segment (21a) is a straight edge; The first arc edge (21b) has a heat-affected zone, while the middle section (21a) does not have a heat-affected zone; or, the surface roughness of the first arc edge (21b) is less than the surface roughness of the middle section (21a).

5. The electrode (100) according to claim 1, characterized in that, Each of the side edges (22) includes a side slope (22c) connected to the first arc edge (21b), and each side slope (22c) is inclined toward the other side edge (22) in a direction pointing toward the top edge (21).

6. The electrode (100) according to claim 5, characterized in that, Each of the side edges (22) further includes a second arc edge (22d), which transitions between the end edge (11) of the body (10) and the side bevel (22c), with the second arc edges (22d) of the two side edges (22) curving toward each other.

7. The electrode (100) according to claim 5, characterized in that, Each of the side edges (22) intersects the corresponding first arc edge (21b) at position p, the first boundary line (I1) between the second coating area (t2) and the empty foil area (t3) intersects the side edge (22) at position A, the position of the top edge (21) farthest from the body (10) along the width direction (Y) of the body (10) is position b, and the inclination angle of the side slope edge (22c) is θ1; Along the width direction (Y) of the main body (10), the distance between position p and position b is L2, the distance between position b and position A is L3, and the protrusion dimension of the tab (20) along the width direction (Y) is L4; The electrode (100) satisfies at least one of the following conditions: 1 / 8 < L2 / L3 < 1; 1mm≤L4-L3≤5mm; and, 0°<θ1≤15°.

8. The electrode (100) according to claim 1, characterized in that, The first coating region (t1) and the second coating region (t2) are electrode material coating regions (t01) of the same material; or, The first coating area (t1) includes a first sub-area (t11) and a second sub-area (t12) arranged adjacent to each other along the width direction (Y). The first sub-area (t11) is an electrode material coating area (t01), and the second sub-area (t12) and the second coating area (t2) are adjacent and are both insulating material coating areas (t02) of the same material.

9. A method for preparing an electrode sheet (100), characterized in that, include: The laser cutting device is invoked to perform a tab cutting operation on the bare electrode sheet (100A) located in its working plane along the set trajectory (G) to process the bare electrode sheet (100A) into an electrode sheet (100) with tabs (20); Wherein, the set trajectory (G) is located in the xy plane coordinate system determined by the working plane, the bare electrode (100A) includes a foil area (T2) and a coating area (T1) arranged adjacent to each other along the y-axis, the foil area (T2) and the coating area (T1) are arranged longitudinally along the x-axis, and the foil area (T2) includes an outer edge (T21) arranged away from the coating area (T1); The set trajectory (G) includes a first trajectory (G1) passing through the foil area (T2) to form the top edge (21) of the electrode (100) and a second trajectory (G2) passing through the coating area (T1) and the foil area (T2) to form the side edge (22) of the electrode (100); the first trajectory (G1) includes a first arc-shaped trajectory segment (G11) located in the foil area (T2), the first arc-shaped trajectory segment (G11) intersects with the second trajectory (G2) in the foil area (T2), the first arc-shaped trajectory segment (G11) bends toward the side away from the coating area (T1), and the angle between the first arc-shaped trajectory segment (G11) and the tangent of the second trajectory (G2) at the connection point is θ2', 15°≤θ2'<90°.

10. The method for preparing the electrode (100) according to claim 9, characterized in that, The first trajectory (G1) includes two first arc-shaped trajectory segments (G11) arranged at intervals along the x-axis, and an intermediate trajectory segment (G12) connecting the two first arc-shaped trajectory segments (G11); The intermediate trajectory segment (G12) is located in the foil area (T2) and is either straight or curved; or, the intermediate trajectory segment (G12) is located outside the range of the bare electrode (100); or, the intermediate trajectory segment (G12) is an arc-shaped trajectory that smoothly connects with each of the first arc-shaped trajectory segments (G11).

11. The method for preparing the electrode (100) according to claim 9, characterized in that, The second trajectory (G2) comprises two sub-trajectories (G21); Each of the sub-trajectories (G21) includes an end edge trajectory (G21c) located in the coating region (T1) to form the end edge (11) of the electrode (100), and a side edge trajectory (G21d) passing through the coating region (T1) and the foil region (T2) to form the side edge (22). Each side edge trajectory (G21d) intersects independently with a first arcuate trajectory segment (G11) in the foil region (T2). The end edge trajectory (G21c) is located on the side of the side edge trajectory (G21d) away from the first arcuate trajectory segment (G11). Each of the first trajectory (G1) intersects with two of the sub-trajectories (G21), and the two sub-trajectories (G21) are discontinuously arranged along the x-axis.

12. The method for preparing the electrode (100) according to claim 9, characterized in that, The projection of the boundary line between the coating area (T1) and the foil area (T2) in the xy plane coordinate system is used as the first reference line (F1); the foil area (T2) includes an outer edge (T21) that is away from the coating area (T1), and the projection of the outer edge (T21) in the xy plane coordinate system is used as the second reference line (F2). The intersection of the first arc-shaped trajectory segment (G11) and the second trajectory (G2) is position p'. The position where the first trajectory (G1) is farthest from the coating area (T1) is position b'. The intersection of the second trajectory (G2) and the first reference line (F1) is position A'. The distance between position b' and position A' along the y-axis is L3'. The minimum distance between each of the first trajectory (G1) and the second reference line (F2) is L1', the maximum distance between the second trajectory (G2) and the second reference line (F2) is L', and the farthest distance between position b' and the second trajectory (G2) along the y-axis is L4', satisfying: 1 / 8 < L2' / L3' < 1; 1mm≤L4'-L3'≤5mm; and / or 1 / 8≤L1' / L'≤7 / 8.

13. The method for preparing the electrode (100) according to claim 9, characterized in that, The laser cutting device is invoked to perform a tab cutting operation on the bare electrode sheet (100) located in its working plane along a set trajectory (G), including: The first and second laser cutters of the laser cutting device are invoked to perform tab cutting operations on the bare electrode sheet (100) located in the working plane of the laser cutting device along the first trajectory (G1) and the second trajectory (G2) towards the positive x-axis, respectively.

14. The method for preparing the electrode (100) according to claim 11, characterized in that, The set trajectory (G) also includes a third trajectory (G3) and a plurality of first trajectories (G1) arranged at intervals along the x-axis; Multiple sets of the sub-trajectories (G21) are arranged sequentially at intervals along the x-axis. Each set of the sub-trajectories (G21) intersects with the same first trajectory (G1). In each pair of adjacent sets of sub-trajectories (G21), the edge trajectories (G21c) of the two sub-trajectories (G21) that are close to each other are connected via the third trajectory (G3). The sub-trajectories (G21) in each group, the sub-trajectories (G21) located on the same side as the first trajectory (G1) are called the first sub-trajectories (G21), and the sub-trajectories (G21) on the other side are called the second sub-trajectories (G21). Accordingly, the laser cutting device is invoked to perform a tab cutting operation on the bare electrode sheet (100) located in its working plane along the set trajectory (G), including: Multiple laser cutters of the laser cutting device are invoked to perform tab cutting operations on bare electrode sheets (100) located in the working plane of the laser cutting device, respectively, along the positive x-axis of the first sub-track (G21), the first track (G1), the second sub-track (G21), and the third track (G3).

15. The method for preparing the electrode (100) according to any one of claims 9-14, characterized in that, The coating area (T1) includes an electrode material coating area (t01) and an insulating material coating area (T1) arranged adjacently along the y-axis, and the insulating material coating area (T1) and the foil area (T2) are adjacent to each other; the second trajectory (G2) is located outside the range of the electrode material coating area (t01) and passes through the insulating material coating area (T1); or, The coating area (T1) is the electrode material coating area (t01), and the second trajectory (G2) passes through the electrode material coating area (t01).

16. An electrode preparation apparatus, characterized in that, include: Laser cutting equipment; and A control device, connected to the laser cutting device, is used to control the operation of the laser cutting device according to the electrode preparation method as described in any one of claims 9-15.

17. A single battery cell (1000), characterized in that, Includes the electrode (100) as described in any one of claims 1-8.

18. An electrical appliance, characterized in that, Includes the battery cell (1000) as described in claim 17.

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