Pole piece, electrochemical device, and electronic device

Abstract

The application discloses a pole piece, an electrochemical device and an electronic device. The pole piece comprises a current collector and a pole lug. The pole lug is connected with the current collector. A cut corner part is arranged at an end corner of one end of the pole lug away from the current collector. The cut corner part is arranged at the end corner of the one end of the pole lug away from the current collector, so that the swing stiffness and the torsional stiffness of the pole lug are improved, the pole lug is prevented from being folded and inserted during the winding of the pole piece, and the production yield of the electrochemical device is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to an electrode, an electrochemical device, and an electronic device. Background Technology

[0002] Batteries with multi-tab structured electrodes have tabs that are led out in multiple winding layers of the cell, which greatly shortens the electron conduction path and can significantly reduce the battery's internal resistance. This allows them to meet the needs of high-rate applications such as mobile phones, laptops, drones, power tools, electric vehicles, and electric two-wheelers. Summary of the Invention

[0003] However, the inventors of this application have discovered that existing multi-tab structure electrodes are prone to tab folding and in-line insertion during the winding process, which seriously affects the production yield.

[0004] In view of this, this application provides an electrode, an electrochemical device, and an electronic device, which can effectively improve the folding and insertion phenomena of the electrode tab during the production process and improve the production yield of the electrochemical device.

[0005] In a first aspect, this application provides an electrode sheet, including a current collector and an electrode tab; the electrode tab is connected to the current collector; a chamfered portion is provided at the end of the electrode tab opposite to the current collector. By providing a chamfered portion at the end of the electrode tab opposite to the current collector, the swing stiffness and torsional stiffness of the electrode tab can be improved, thereby suppressing the folding and indentation phenomena of the electrode tab during the electrode sheet winding process, and improving the production yield of the electrochemical device.

[0006] In some embodiments, the tabs are provided with chamfered portions at both corners of the end opposite to the current collector. Providing chamfered portions at both corners helps to improve the swing stiffness and torsional stiffness on both sides of the tabs, further suppressing folding and indentation phenomena of the tabs during the electrode winding process.

[0007] In some embodiments, the outer edge of the chamfered portion is independently selected from any one of a straight line, an outwardly convex arc, or an inwardly concave arc.

[0008] In some embodiments, the tab is formed by extending the current collector. In this case, on the one hand, the connection strength between the tab and the current collector can be improved, reducing the risk of the tab falling off; on the other hand, the manufacturing of the tab can be greatly simplified, and processing efficiency can be improved.

[0009] In some embodiments, the electrode includes multiple tabs. Including multiple tabs can significantly improve the rate performance of the electrochemical device, thereby better meeting the needs of high-rate applications.

[0010] In some embodiments, the outer edge of the chamfered portion has a first endpoint and a second endpoint; the tab has a first side and a bottom edge connected to the current collector, one end of the first side is connected to the bottom edge, and the other end of the first side is connected to the first endpoint; the angle between the first side and the bottom edge is α, the angle between the line connecting the first endpoint and the second endpoint and the first side is λ, β = λ - (180° - α), and satisfies: β < α. By satisfying β < α, the swing stiffness and torsional stiffness of the tab at the end can be improved, thereby suppressing the tab from folding or inserting during the electrode winding process, and improving the production yield of the electrochemical device.

[0011] In some embodiments, α-β ≥ 9°. In some embodiments, α-β ≥ 15°. In this case, the swinging and twisting of the tab at the end can be further restricted, thereby further suppressing the folding and insertion of the tab during the electrode winding process.

[0012] In some embodiments, 0° < α ≤ 90°. In some embodiments, 40° ≤ α ≤ 86°. In this case, the first side edge and the bottom edge are set at an acute angle, and the width of the tab gradually narrows away from the current collector, which can further improve the swing stiffness and torsional stiffness of the tab at the end, thereby further suppressing the tab from folding or inserting during the winding of the electrode sheet.

[0013] In some implementations, α-β ≤ 75°.

[0014] In some embodiments, the bottom edge width of the electrode tab is L, the height of the electrode tab is H, and the top edge width of the electrode tab is 2l; wherein, the width direction of the electrode tab is parallel to the length direction of the current collector, and the height direction of the electrode tab is perpendicular to the length direction of the current collector, satisfying: 0≤l≤0.8(L / 2-H / tanα).

[0015] In some implementations, the following condition is satisfied: 0 ≤ l ≤ 0.4 (L / 2 - H / tanα). This further restricts the swinging and twisting of the tab at the end, thereby further suppressing the folding and insertion of the tab during the electrode winding process.

[0016] In some implementations, the length of the first side is h, satisfying: 0.2H / sinα≤h≤0.8H / sinα.

[0017] In some implementations, the following condition is satisfied: 0.3H / sinα ≤ h ≤ 0.7H / sinα. This further restricts the swaying and twisting of the tab at its end, thereby further suppressing folding and insertion of the tab during the electrode winding process.

[0018] Secondly, this application also provides a method for preparing a battery cell, including the step of winding the electrode sheet described in any of the above claims.

[0019] Thirdly, this application also provides an electrochemical device, including the electrode sheet described in any of the above claims or the battery cell prepared by the above preparation method.

[0020] Fourthly, this application also provides an electronic device including any of the electrochemical devices described above.

[0021] This application improves the swing stiffness and torsional stiffness of the electrode by setting a chamfered part at the end of the electrode away from the current collector. The number of electrode folds during the winding process is significantly reduced, and the corresponding cell production failure rate is also greatly reduced. Therefore, it can effectively improve the folding and insertion phenomenon of the electrode during the winding process and improve the production yield of the electrochemical device. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0023] Figure 1 This is a schematic diagram of a base electrode structure in the prior art;

[0024] Figure 2 This is a schematic diagram of the chamfered electrode tab described in this application;

[0025] Figure 3 This is a schematic diagram of the structure of the chamfered electrode tab in the embodiment of this application, where the chamfered angle is a straight chamfer.

[0026] Figure 4 This is a schematic diagram of the structure of the chamfered electrode tab in the embodiment of this application, which is a concave arc chamfer.

[0027] Figure 5 This is a schematic diagram of the structure of the chamfered electrode tab with an outwardly convex arc chamfer in the embodiment of this application;

[0028] Figure 6 This is a schematic diagram showing the parameters of the chamfered electrode tabs in the embodiments of this application, where the chamfered angle is a straight chamfer.

[0029] Figure 7 This is a schematic diagram showing the specific parameters of the chamfered electrode tabs in the embodiments of this application;

[0030] Figure 8 Image showing the modal analysis results of the base electrode structure in the prior art. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0032] Please see Figure 1 The base tab structure in the prior art is usually an isosceles trapezoidal tab, that is, the outer contour of the tab is an isosceles trapezoidal structure.

[0033] The inventors of this application have discovered that during the electrode winding process, existing base tabs are prone to folding and insertion. This is especially true for batteries with multi-tab structure electrodes, where the probability of tab folding and insertion during winding is greatly increased, seriously affecting production yield.

[0034] In view of this, this application proposes an electrode, an electrochemical device, and an electronic device to improve or at least partially solve the above-mentioned technical problems.

[0035] A type of electrode

[0036] Please see Figure 2 The electrode sheet includes: a current collector 1 and an electrode tab 2 (sometimes referred to as a chamfered electrode tab in this document); the electrode tab 2 is connected to the current collector 1; specifically, the end of the electrode tab 2 closest to the current collector 1 is connected to the current collector 1. The connection can be integral molding, bonding, welding or other fixing methods, as long as the connection and fixing of the electrode tab 2 and the current collector 1 can be achieved. This application does not limit this. Specifically, in some examples, the electrode tab 2 is formed by extending the current collector 1. In this case, the electrode tab 2 and the current collector 1 are integrally molded. During the electrode sheet cutting process, the corresponding electrode tab 2 can be obtained by cutting the empty foil area at the edge of the current collector 1, which greatly simplifies the manufacturing of the electrode tab 2 and improves the processing efficiency; a chamfered portion 21 is provided at the end corner of the electrode tab 2 opposite to the current collector 1. By providing the chamfered portion 21 at one or both end corners of the end of the electrode 2 away from the current collector 1 (i.e., the outer end of the electrode 2), the swing stiffness and torsional stiffness of the electrode 2 can be improved, thereby suppressing the folding and indentation phenomena of the electrode 2 during the electrode winding process.

[0037] Optionally, in some examples, the chamfered portion 21 is provided on one end corner of the outer end of the electrode 2; or in other examples, the chamfered portion 21 is provided on both end corners of the outer end of the electrode 2.

[0038] Please see Figures 3-5In some examples, the two end corners of the tab 2 opposite to the current collector 1 are provided with chamfered portions 21; the two chamfered portions 21 are located at the end corners of the outer end of the tab 2 and are centrally symmetrical, which helps to improve the swing stiffness and torsional stiffness on both sides of the tab 2, and further suppresses the tab 2 from folding or inserting during the electrode winding process. In some examples, the outer edge 211 of the chamfered portion 21 is independently selected from any one of a straight line, an outwardly convex arc, or an inwardly concave arc.

[0039] Optionally, in some examples, a chamfered portion 21 is provided at one end corner of the electrode 2 away from the current collector 1. The outer edge 211 of the chamfered portion 21 can be a straight line, a convex arc, or a concave arc; preferably, the outer edge 211 of the chamfered portion 21 is a concave arc. In other examples, chamfered portions 21 are provided at both end corners of the electrode 2 away from the current collector 1, and the outer edges 211 of the two chamfered portions 21 are the same, both being a straight line, a convex arc, or a concave arc; preferably, the outer edges 211 of the two chamfered portions 21 are both concave arcs. And in other examples, chamfered portions 21 are provided at both end corners of the electrode 2 away from the current collector 1, and the outer edges 211 of the two chamfered portions 21 are different; one of the two chamfered portions 21 has an outer edge 211 that is a straight line, and the other chamfered portion 21 has an outer edge 211 that is a convex arc or a concave arc.

[0040] like Figure 3 As shown, the two corners of the outer end of the electrode 2 are provided with chamfered portions 21, and the outer edges 211 of the two chamfered portions 21 are straight lines and are centrally symmetrical. In this case, it can be said that the two corners of the outer end of the electrode 2 are provided with straight chamfers.

[0041] like Figure 4 As shown, the two corners of the outer end of the electrode 2 are provided with chamfered portions 21, and the outer edges 211 of the two chamfered portions 21 are concave arcs and are centrally symmetrical. In this case, it can be said that the two corners of the outer end of the electrode 2 are provided with concave arc chamfers.

[0042] like Figure 5 As shown, the two corners of the outer end of the electrode 2 are provided with chamfered portions 21, and the outer edges 211 of the two chamfered portions 21 are both outwardly convex arcs and are centrally symmetrical. In this case, it can be said that the two corners of the outer end of the electrode 2 are provided with outwardly convex arc chamfers.

[0043] Please see Figure 6The outer edge 211 of the chamfered portion 21 has a first endpoint and a second endpoint; the tab 2 has a first side and a bottom edge connected to the current collector 1, one end of the first side is connected to the bottom edge, and the other end of the first side is connected to the first endpoint; the angle between the first side and the bottom edge is α (slope angle), and the angle between the line connecting the first endpoint and the second endpoint and the first side is λ, β=λ-(180°-α), satisfying: β<α. By limiting the angle β between the line connecting the first endpoint and the second endpoint in the chamfered portion 21 and the horizontal line, so that it satisfies: β<α, the swing stiffness and torsional stiffness of the tab 2 at the outer end can be improved, thereby suppressing the tab 2 from folding and inserting during the electrode winding process; the horizontal line is a straight line parallel to the bottom edge.

[0044] Optionally, in some examples, the electrode sheet satisfies α-β ≥ 9°. By satisfying α-β ≥ 9°, the swing stiffness and torsional stiffness of the tab 2 at its outer end can be improved, thereby further suppressing the tab 2 from folding or inserting during the electrode sheet winding process. Exemplarily, the difference between α and β (α-β) is 9°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, or any combination of two of the above values. Optionally, in some examples, the electrode sheet satisfies α-β ≥ 15°; in this case, the swing and torsion of the tab 2 at its outer end can be further limited, thereby further suppressing the tab 2 from folding or inserting during the electrode sheet winding process. In other examples, the electrode sheet satisfies α-β ≤ 75°.

[0045] In some examples, the electrode sheet satisfies 0° < α ≤ 90°. For example, the value of α ranges from 10°, 20°, 40°, 60°, 80°, 86°, 90°, or any combination of two of the above values. In some examples, the electrode sheet satisfies 40° ≤ α ≤ 86°; in this case, the first side edge and the bottom edge form an acute angle, and the width of the electrode tab gradually narrows away from the current collector, which can further improve the swing stiffness of the electrode tab 2 at its outer end, thereby further suppressing the folding and indentation phenomena of the electrode tab 2 during the electrode sheet winding process.

[0046] Combination Figure 6The base width of the tab 2 is L, the height of the tab 2 is H, and the top width of the tab 2 is 2l, satisfying: 0 ≤ l ≤ 0.8(L / 2 - H / tanα); wherein, the width direction of the tab 2 is parallel to the length direction of the current collector 1, and the height direction of the tab 2 is perpendicular to the length direction of the current collector 1. (L / 2 - H / tanα) is the half-width of the top edge of the base tab, denoted as parameter B. When cutting the tab, it is equivalent to cutting off the top width of the base tab. The range of the half-width l of the top edge of the tab 2 is 0 to 0.8B, that is, the length cut off relative to the half-width of the top edge of the base tab is Bl (i.e., ...). Figure 6 The distance when the extension line of one end of the top half-width l intersects the extension line of the first side h).

[0047] For example, the top half-width l of the tab 2 is 0, 0.01B, 0.1B, 0.15B, 0.2B, 0.25B, 0.3B, 0.35B, 0.4B, 0.6B, 0.8B, or any two of the above values.

[0048] Preferably, the top edge half-width l of the tab 2 satisfies: 0 ≤ l ≤ 0.4 (L / 2 - H / tanα); that is, l satisfies: 0 ≤ l ≤ 0.4B. In this case, the swinging and twisting of the tab 2 at the outer end can be further restricted, thereby further suppressing the folding and indentation of the tab 2 during the winding of the electrode sheet.

[0049] Moreover, combined Figure 6 The length of the first side is h, satisfying: 0.2H / sinα ≤ h ≤ 0.8H / sinα. Here, H / sinα is the length of the hypotenuse of the base tab. One end of the hypotenuse of the base tab is connected to its top edge, and the other end is connected to its bottom edge. Let (H / sinα) be denoted as parameter A. When cutting the tab, it is equivalent to cutting off the hypotenuse of the base tab. The length of the first side of the tab 2 ranges from 0.2A to 0.8A, meaning the actual length cut off from the hypotenuse of the base tab is Ah (i.e.,...). Figure 6 The distance when the extension of the first side h intersects the extension of the top half-width l).

[0050] For example, the length h of the first side is 0.2A, 0.3A, 0.4A, 0.5A, 0.6A, 0.7A, 0.8A, or a range consisting of any two of the above values.

[0051] Preferably, the length h of the first side satisfies: 0.3H / sinα ≤ h ≤ 0.7H / sinα; that is, h satisfies: 0.3A ≤ h ≤ 0.7A. In this case, the swinging and twisting of the tab 2 at the outer end can be further restricted, thereby further suppressing the folding and insertion of the tab 2 during the winding of the electrode sheet.

[0052] In some examples, the electrode is a positive electrode. In some examples, the electrode is a negative electrode.

[0053] In some examples, the electrode further includes an active material layer located on the surface of the current collector. In some examples, the active material layer is a positive electrode active material layer, which includes a positive electrode active material. In some examples, the active material layer is a negative electrode active material layer, which includes a negative electrode active material.

[0054] An electrochemical device

[0055] The electrochemical device includes a battery cell comprising any of the electrodes described above in this application. The battery cell can be prepared according to conventional methods in the art; specifically, the preparation of the battery cell includes the step of winding the electrodes described above.

[0056] The electrochemical device of this application can include any device in which an electrochemical reaction occurs, such as a lithium-ion battery, a sodium-ion battery, etc.; specific examples include all types of primary or secondary batteries. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0057] An electronic device

[0058] The electronic device includes any of the electrochemical devices described above in this application. The electronic device of this application can be used in, but is not limited to, laptops, pen-based computers, mobile computers, e-book players, portable telephones, portable fax machines, portable copiers, portable printers, stereo headphones, video recorders, LCD TVs, portable cleaners, portable CD players, mini CDs, transceivers, electronic notebooks, calculators, memory cards, portable recorders, radios, backup power supplies, motors, automobiles, motorcycles, electric bicycles, bicycles, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, large household batteries, and lithium-ion capacitors, etc.

[0059] The following examples and comparative examples illustrate the implementation of this application in more detail.

[0060] Taking a multi-tab large soft-pack battery as an example, we compared the production yield improvement effect. The number of samples was 200. There are 108 die-cut tabs in the wound cells of a large soft-pack battery. We counted the number of wound cells with tab folds during the winding process.

[0061] The height of the base tab in this verification is H = 24 mm, the bottom width is L = 35 mm, the slope angle is α = 86°, the side length (parameter A) is calculated to be 24.06 mm, and the top width (parameter B) is calculated to be 15.8 mm. The corresponding experimental results are shown in Table 2.

[0062] The parameters after chamfering the two end angles of the base tab are shown in Table 2. The outer edge of the chamfered part can be a straight line, a convex arc, or a concave arc. In Example 1, the straight chamfered tab has a β angle of 45°, a first side length h of 15mm, and a top half-width l of 7.45mm. In Examples 2-3, the convex arc chamfer and the concave arc chamfer are both obtained by changing the straight chamfer, that is, the positions of the hypotenuse and the top edge are consistent with the straight chamfer. The vertical distance from the point of maximum radius of curvature in the convex arc and the concave arc to the straight chamfer is 2.5mm. The corresponding dimensions are as follows: Figure 7 As shown; the experimental data are shown in Table 1 below:

[0063] Table 1

[0064]

[0065]

[0066] As can be seen from the parameter characteristics and test results in Table 1, compared with Comparative Example 1, Examples 1 to 3 respectively cut the base tabs to obtain chamfered portions. In Example 1, the outer edge of the chamfered portion after cutting is a straight line, i.e., a straight chamfer. In the test, 2 out of 200 cells with straight chamfered tabs experienced tab flipping, corresponding to a cell production failure rate of 1%. In Example 2, the outer edge of the chamfered portion after cutting is a convex arc, i.e., a convex arc chamfer. In the test, 4 out of 200 cells with convex arc chamfered tabs experienced tab flipping, corresponding to a cell production failure rate of 2%. In Example 3, the outer edge of the chamfered portion after cutting is a concave arc, i.e., a concave arc chamfer. In the test, 1 out of 200 cells with concave arc chamfered tabs experienced tab flipping, corresponding to a cell production failure rate of 0.5%. It is evident that the concave arc-shaped chamfered tab has the best effect on improving the swing and torsional stiffness, and its corresponding cell production failure rate is only 0.5%, which is far lower than the 6% cell production failure rate of the base tab.

[0067] A comparison of Examples 4-8 with Example 9 shows that controlling the top half-width l of the chamfered electrode tab within 0-0.8B, i.e. 0≤l≤0.8(L / 2-H / tanα), results in a stronger chamfered electrode tab than those outside this range. In other words, when the top half-width l is within the range of 0-0.8B, the folding restriction effect is better. For example, in Example 9, the value of l is 0.9 (L / 2-H / tanα). The number of tabs that folded during the test of 200 cells was 7, which is much higher than the number of folds in Examples 4-8. The number of folds in Examples 4-8 was less than or equal to 3, and could be as low as 1. The cell production failure rate corresponding to Example 9 was 3.5%, while the cell production failure rate corresponding to Examples 4-8 was no more than 1.5%. Moreover, compared with Examples 7-8, Examples 4-6 controlled the top half-width l of the chamfered tab to be 0-0.4B, that is, 0≤l≤0.4(L / 2-H / tanα), which had a better effect on limiting folding and the corresponding cell production failure rate was also lower.

[0068] A comparison of Examples 11-15 with Examples 10 and 16 shows that controlling the length of the first side h of the chamfered electrode tab within 0.2A to 0.8A, i.e. 0.2H / sinα≤h≤0.8H / sinα, results in a chamfered electrode tab with better swing and torsional strength than those outside this range. In other words, when the length of the first side h is within the range of 0.2A to 0.8A, the effect of limiting folding is better. For example, in Examples 10 and 16, the values ​​of the first side h are 0.1A and 0.9A, respectively. The number of tab folds in the 200 cells tested in both examples is 6, which is much higher than the number of folds in Examples 11-15, where the number of folds is less than or equal to 4, and can be as low as 1. Furthermore, the cell production failure rate in Examples 10 and 16 is 3%, while the cell production failure rate in Examples 11-15 is no more than 2%. Moreover, compared with Examples 11 and 15, Examples 12-14 control the first side h to 0.3A-0.7A, i.e., 0.3H / sinα≤h≤0.7H / sinα, which has a better effect on limiting folds and results in a lower cell production failure rate.

[0069] Compared with other examples, when α-β≥15° and α-β≤75°, the number of tabs folding in the battery cell during production is significantly reduced, the battery cell production failure rate is reduced, and the improvement effect is significant.

[0070] Furthermore, to compare stiffness, this application employs modal analysis for quantification. In modal analysis, the first-order characteristic frequency corresponds to the oscillating stiffness, and the second-order characteristic frequency corresponds to the torsional stiffness (e.g.,...). Figure 8Table 2 below compares the modal analysis results of the base tab of Comparative Example 1 and the chamfered tab described in Embodiment 1 of this application:

[0071] Table 2

[0072] Group First-order characteristic frequency Second-order characteristic frequency Base Electrode 5.85 7.64 Cut-angle pole ear 6.21 9.13

[0073] It can be seen that the first-order and second-order characteristic frequencies of the chamfered electrode tab in Embodiment 1 of this application are significantly improved. The higher the first-order frequency, the less likely it is to swing up and down, and the higher the second-order frequency, the less likely it is to swing left and right. It is evident that the swing and torsional stiffness of the chamfered electrode tab are improved, thereby suppressing the folding and insertion phenomena of the electrode tab during the electrode winding process.

[0074] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are 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, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0075] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A pole piece, comprising: A current collector and an electrode tab; the electrode tab is connected to the current collector; characterized in that a chamfered portion is provided at the end of the electrode tab facing away from the current collector; The outer edge of the chamfered portion has a first endpoint and a second endpoint; The electrode has a first side and a bottom edge connected to the current collector. One end of the first side is connected to the bottom edge, and the other end of the first side is connected to the first end point. The angle between the first side and the bottom is α, the angle between the line connecting the first endpoint and the second endpoint and the first side is λ, β=λ-(180°-α), satisfying: β<α; The bottom edge width of the electrode tab is L, the height of the electrode tab is H, the top edge width of the electrode tab is 2l, and the length of the first side edge is h. The width direction of the electrode tab is parallel to the length direction of the current collector, and the height direction of the electrode tab is perpendicular to the length direction of the current collector. The electrode sheet satisfies the following conditions: (1)0≤l≤0.8(L / 2-H / tanα); (2)0.2H / sinα≤h≤0.8H / sinα.

2. The electrode sheet according to claim 1, characterized in that, The electrode sheet satisfies at least one of the following conditions: (1) The two end corners of the electrode tab away from the current collector are provided with chamfered portions; (2) The outer edge of the chamfered portion is independently selected from any one of a straight line, an outwardly convex arc, or an inwardly concave arc; (3) The electrode tab is formed by extending the current collector; (4) The electrode includes a plurality of the tabs.

3. The electrode sheet according to claim 1, characterized in that, The electrode sheet satisfies at least one of the following conditions: （1）α-β≥9°； （2）0°＜α≤90°。 4. The electrode sheet according to claim 3, characterized in that, The electrode sheet satisfies at least one of the following conditions: （1）α-β≥15°； （2）α-β≤75°； （3）40°≤α≤86°。 5. The electrode sheet according to claim 1, characterized in that, The electrode sheet satisfies at least one of the following conditions: (1)0≤l≤0.4(L / 2-H / tanα); (2)0.3H / sinα≤h≤0.7H / sinα.

6. A method for preparing a battery cell, characterized in that, The step includes winding the electrode sheet according to any one of claims 1 to 5.

7. An electrochemical device, characterized in that, Includes the electrode sheet according to any one of claims 1 to 5 or the battery cell prepared by the preparation method according to claim 6.

8. An electronic device, characterized in that, Includes the electrochemical device as described in claim 7.

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