Electrochemical devices and electronic devices

Abstract

The electrochemical device and electronic device provided in the embodiments of the present application, the electrochemical device includes a first pole piece arranged in a wound manner, the first pole piece includes a first current collector and a first protrusion extending from the first current collector along a first direction. The thickness direction of the first protrusion is defined as the second direction, the second direction is perpendicular to the first direction, and the direction perpendicular to the first direction and the second direction is defined as the third direction. When viewed from the second direction, the first current collector has a first end edge, the first protrusion has a third edge and a first edge and a second edge arranged oppositely, the first edge connects the third edge and the first end edge, and the second edge connects the first edge and the first end edge. In the first direction, the extension line of the first edge intersects the extension line of the second edge, and the acute angle formed by the first edge and the first end edge is α, 25°≤α≤65°. In this way, the risk of the first protrusion flipping during the winding process is reduced, and the safety of the electrochemical device is improved.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of energy storage technology, and in particular to an electrochemical device and an electronic device. Background Art

[0002] Electrochemical devices are commonly used in many electronic devices, used to power electronic devices such as mobile phones and tablets, freeing them from the constraints of power cords. Electrochemical devices typically include a first electrode sheet, a second electrode sheet, and a separator. The separator is disposed between the first and second electrode sheets. Multiple tabs are die-cut from the hollow foil area of ​​the current collectors of the first and second electrode sheets. These tabs are then wound together to form an electrode assembly. Multiple tabs of the same polarity overlap and are fixed across the thickness of the electrochemical device, thereby reducing internal resistance and improving charge and discharge performance. Summary of the Invention

[0003] During the implementation of the present application, the inventors of the present application discovered that the tabs die-cut from the existing current collector are subject to centrifugal force during the winding process of the pole pieces, especially during high-speed winding. The centrifugal force is relatively large, and the tabs are less able to resist the centrifugal force, making it easy for the tabs to fold. The folded tabs pose a risk of short-circuiting pole pieces of different polarities, thereby posing a safety hazard.

[0004] In view of the above problems, embodiments of the present application provide an electrochemical device and an electronic device to improve the above problems.

[0005] The embodiments of the present application solve the technical problems by adopting the following technical solutions:

[0006] An electrochemical device includes an electrode assembly, the electrode assembly includes a first electrode sheet arranged in a wound manner, the first electrode sheet includes a first current collector and a first protrusion, and the first protrusion extends from the first current collector along a first direction. The thickness direction of the first protrusion is defined as the second direction, the second direction is perpendicular to the first direction, and the direction perpendicular to the first and second directions is defined as the third direction. When viewed from the second direction, the first current collector has a first end edge, the first protrusion has a first edge, a second edge, and a third edge, the first edge and the second edge are arranged opposite each other, one end of the third edge is connected to one end of the first edge, the other end of the third edge is connected to one end of the second edge, the other end of the first edge is connected to the first end edge, and the other end of the second edge is connected to the first end edge. In the first direction, the extension line of the first edge intersects the extension line of the second edge, and the acute angle formed by the first edge and the first end edge is α, 25°≤α≤65°.

[0007] The angle between the first side and the first end side is set to α, 25°≤α≤65°, the strength of the connection between the first protrusion and the first current collector is sufficient, which enhances the ability of the first protrusion to resist the centrifugal force of winding during the winding process, reduces the risk of the first protrusion folding during the winding of the first electrode sheet, is beneficial to improving the safety of the electrochemical device, and can also improve production efficiency.

[0008] In some embodiments, the acute angle formed by the second side and the first end side is β, 25°≤ ≤65°.

[0009] The acute angle β formed by the second side and the first end side satisfies 25°≤β≤65°, which can further improve the strength of the connection between the first protrusion and the first current collector, and is conducive to further reducing the risk of the first protrusion folding during the winding process of the first pole sheet, thereby further improving production efficiency.

[0010] In some embodiments, the intersection of the first side and the first end side is the first endpoint, the intersection of the second side and the first end side is the second endpoint, along the third direction, the distance between the first endpoint and the second endpoint is L2, and the length of the third side in the third direction is L1, satisfying L2-85.8≤L1≤L2-4.7.

[0011] When L1 and L2 satisfy the above relationship, the strength of the connection between the first protrusion and the first current collector is sufficient, and L2 is always greater than L1, which reduces the risk of the first protrusion folding during the winding process, which is beneficial to improving the safety of the electrochemical device. The area of ​​the first protrusion can also be set to improve the reliability of the connection between the first protrusion and other components, and reduce the material cost of forming the first protrusion.

[0012] In some embodiments, in the first direction, a distance between the third side and the first end side is 5 mm to 20 mm.

[0013] In some embodiments, the first edge includes a first connecting segment and a second connecting segment connected to each other, the first connecting segment being connected to the third edge, the second connecting segment being connected to the first end edge, both the first connecting segment and the second connecting segment being arc-shaped, the first connecting segment being convex along the first direction, and the second connecting segment being concave along the first direction. This can improve the manufacturing efficiency of the die-cut first tab, reduce the quality of the first convex portion deviating from the first end edge, reduce the risk of folding during the winding process, and improve safety.

[0014] In some embodiments, the first side includes a first connecting segment and a second connecting segment connected to each other, the first connecting segment being connected to the third side, the second connecting segment being connected to the first end side, the first connecting segment being linear, the second connecting segment being arc-shaped, and the second connecting segment being concavely arranged along the first direction, thereby facilitating the positioning and connection of the first protrusion.

[0015] In some embodiments, the first side includes a first connecting segment and a second connecting segment connected to each other, the first connecting segment is connected to the third side, the second connecting segment is connected to the first end side, the first connecting segment is arc-shaped, the second connecting segment is linear, and the first connecting segment is protruding along the first direction, which facilitates the positioning and connection of the first protrusion.

[0016] In some embodiments, the first edge includes a first connecting segment and a second connecting segment connected to each other, the first connecting segment is connected to the third edge, the second connecting segment is connected to the first end edge, the first connecting segment includes a first arcuate portion and a first straight portion connected to each other, the first arcuate portion is connected to the third edge, the first straight portion is connected to the second connecting segment, the first arcuate portion is convex along the first direction, the second connecting segment is arc-shaped, and the second connecting segment is concave along the first direction. This can improve the manufacturing efficiency of the die-cut first tab, reduce the quality of the first protrusion away from the first end edge, reduce the risk of folding during the winding process, improve safety, and facilitate the positioning and connection of the first protrusion.

[0017] In some embodiments, the second side includes a third connecting segment and a fourth connecting segment connected to each other, the third connecting segment is connected to the third side, and the fourth connecting segment is connected to the first end side, the third connecting segment and the fourth connecting segment are both arc-shaped, the third connecting segment is convexly arranged along the first direction, and the fourth connecting segment is concavely arranged along the first direction.

[0018] In some embodiments, the second side includes a third connecting segment and a fourth connecting segment connected to each other, the third connecting segment is connected to the third side, the fourth connecting segment is connected to the first end side, the third connecting segment is straight-line, the fourth connecting segment is arc-shaped, and the third connecting segment is concavely arranged along the first direction.

[0019] In some embodiments, the second side includes a third connecting segment and a fourth connecting segment connected to each other, the third connecting segment is connected to the third side, the fourth connecting segment is connected to the first end side, the third connecting segment is arc-shaped, the fourth connecting segment is straight-line-shaped, and the third connecting segment is protruding along the first direction.

[0020] In some embodiments, the second side includes a third connecting segment and a fourth connecting segment connected to each other, the third connecting segment is connected to the third side, the fourth connecting segment is connected to the first end side, the third connecting segment includes a second arc-shaped portion and a second straight line portion connected to each other, the second arc-shaped portion is connected to the third side, the second straight line portion is connected to the fourth connecting segment, the second arc-shaped portion is protruding along the first direction, the third connecting segment is arc-shaped, and the fourth connecting segment is concavely arranged along the first direction.

[0021] In some embodiments, the first pole piece includes a plurality of first protrusions, and the plurality of first protrusions are distributed along the third direction.

[0022] A plurality of first protrusions are provided and can be welded to each other, thereby shortening the path of electron movement, thereby reducing the internal resistance of the electrochemical device and improving the high-rate charge and discharge performance.

[0023] In some embodiments, the first electrode is a negative electrode, the first current collector is a copper foil, and the thickness of the first current collector ranges from 0.5 μm to 6 μm.

[0024] When the first current collector is made of copper foil with a thickness ranging from 0.5 μm to 6 μm, and the angle design between the first side and the first end side is combined, the thickness and weight of the electrochemical device occupied by the first current collector can be reduced, the energy density can be increased, and a higher winding speed can be maintained, thereby improving manufacturing efficiency and safety performance, and increasing the possibility of using thin copper foil in electrochemical devices.

[0025] In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 5 μm. In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 4 μm. In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 3 μm. In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 2 μm. In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 1 μm.

[0026] In some embodiments, the first side and the second side are symmetrically arranged along a first axis, and the first axis passes through a midpoint of the third side along the first direction.

[0027] The first side and the second side are symmetrically arranged about the first axis, so that the angle β between the second side and the first end side also satisfies 25°≤β≤65°, which can further reduce the risk of the first protrusion being folded during the winding process.

[0028] In some embodiments, a first layer comprising an insulating material is disposed on the first protrusion, and the first layer is in contact with the first end edge, thereby improving the quality of the first protrusion near the first end edge, improving the stability of the first protrusion during the winding process, and reducing the risk of folding.

[0029] In some embodiments, the electrode assembly further includes a wound second electrode sheet and an isolation film, wherein the isolation film is disposed between the first electrode sheet and the second electrode sheet.

[0030] The present application also provides an electronic device, comprising the above-mentioned electrochemical device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0032] Figure 1 is a schematic structural diagram of an electrochemical device provided in one embodiment of the present application;

[0033] Figure 2 It is a schematic diagram of the connection between the electrode assembly and the tab assembly;

[0034] Figure 3 yes Figure 2 Schematic diagram of the structure after being cut along the straight line QQ';

[0035] Figure 4 yes Figure 2 Schematic diagram of the structure after being cut along the straight line OO';

[0036] Figure 5 yes Figure 4 Schematic diagram of the structure after the first pole piece is unfolded;

[0037] Figure 6 is a schematic structural diagram of a first pole piece in another embodiment;

[0038] Figure 7 yes Figure 6 An enlarged view of the F1 section;

[0039] Figure 8 is a schematic structural diagram of a first pole piece in yet another embodiment;

[0040] Figure 9 yes Figure 8 An enlarged view of the F2 portion;

[0041] Figure 10 is a schematic structural diagram of a first pole piece in yet another embodiment;

[0042] Figure 11 yes Figure 10 An enlarged view of the F3 portion;

[0043] Figure 12 is a schematic structural diagram of a first pole piece in another embodiment;

[0044] Figure 13 yes Figure 12 An enlarged view of the F4 section;

[0045] Figure 14 is a schematic structural diagram of a first pole piece in yet another embodiment;

[0046] Figure 15 yes Figure 14 An enlarged view of the F5 part;

[0047] Figure 16 is a schematic structural diagram of a first pole piece in another embodiment;

[0048] Figure 17 yes Figure 11 Side view of;

[0049] Figure 18 yes Figure 2 Schematic diagram of the structure after being cut along the straight line PP';

[0050] Figure 19 yes Figure 13 Schematic diagram of the structure after the second pole piece is unfolded;

[0051] Figure 20 is a schematic structural diagram of a second pole piece in another embodiment;

[0052] Figure 21 yes Figure 20 An enlarged view of the F6 section;

[0053] Figure 22 is a structural schematic diagram of a second pole piece in yet another embodiment;

[0054] Figure 23 yes Figure 22 An enlarged view of the F7 section;

[0055] Figure 24 is a schematic structural diagram of a second pole piece in yet another embodiment;

[0056] Figure 25 yes Figure 24 An enlarged view of the F8 portion;

[0057] Figure 26 is a schematic structural diagram of a second pole piece in another embodiment;

[0058] Figure 27 yes Figure 26 An enlarged view of the F9 section;

[0059] Figure 28 is a structural schematic diagram of a second pole piece in yet another embodiment;

[0060] Figure 29 yes Figure 28 An enlarged view of the F10 section;

[0061] Figure 30 is a schematic structural diagram of a second pole piece in another embodiment;

[0062] Figure 31 yes Figure 30 Side view of;

[0063] Figure 32 is a structural block diagram of a battery module according to another embodiment of the present application;

[0064] Figure 33This is a structural block diagram of an electronic device according to another embodiment of the present application. DETAILED DESCRIPTION

[0065] In order to facilitate the understanding of the present application, the present application will be described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as being "fixed on" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as being "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "upper", "lower", "inside", "outside", "vertical", "horizontal", etc. used in this specification indicate an orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", etc. are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0066] Unless otherwise defined, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art to which this application belongs. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used in this specification includes any and all combinations of one or more of the relevant listed items.

[0067] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0068] like Figure 1-3 As shown, an electrochemical device 100 provided in one embodiment of the present application includes a housing 10, an electrode assembly 20, and a tab assembly 30. The electrode assembly 20 is housed in the housing 10, one end of the tab assembly 30 is connected to the electrode assembly 20, and the other end of the tab assembly 30 extends out of the housing 10. The electrode assembly 20 includes a first electrode 21, a second electrode 22, and a separator 23. The separator 23 is disposed between the first electrode 21 and the second electrode 22. The separator 23 is used to reduce the risk of short circuit caused by contact between the first electrode 21 and the second electrode 22. It is understood that the polarity of the first electrode 21 and the second electrode 22 is opposite, that is, if the first electrode 21 is a cathode electrode, the second electrode 22 is an anode electrode; conversely, if the first electrode 21 is an anode electrode, the second electrode 22 is a cathode electrode.

[0069] like Figure 3 As shown, Figure 3for Figure 2 A schematic diagram of the rear electrode assembly 20 cut along line QQ', Figure 3 As shown in FIG, the first pole piece 21, the isolation film 23 and the second pole piece 22 are stacked and wound to form a plurality of flat portions 201 and a plurality of curved portions 202. Figure 3 As shown in FIG, along the winding direction, the portion between the straight line CC' and the straight line TT' in each turn is a flat portion 201, and a curved portion 202 is connected between two adjacent flat portions 201 of the same pole piece. The direction in which the tab assembly 30 extends out of the housing 10 is defined as a fourth direction U, a direction perpendicular to the plurality of flat portions 201 and the fourth direction U is defined as a fifth direction V, and a direction perpendicular to both the fourth direction U and the fifth direction V is defined as a sixth direction W.

[0070] In some embodiments, please combine Figure 4 and Figure 5 , Figure 4 is Figure 2 In the schematic diagram obtained by cutting along the straight line OO', the first pole piece 21 includes a first current collector 211, a first protrusion 212 and a first active material layer 213. The first protrusion 212 extends from the first current collector 211 along the fourth direction U, and the first active material layer 213 is arranged on the surface of the first current collector 211. The first protrusion 212 is connected to the first pole tab 31 of the pole tab assembly 30, which can be directly connected or indirectly connected. In this embodiment, the first protrusion 212 is directly connected to the first pole tab 31. The number of the first protrusions 212 can be one or more, and can be set according to actual needs. In some embodiments, the plurality of first protrusions 212 are distributed on the same side of the first current collector 211. In other embodiments, the plurality of first protrusions 212 are distributed on opposite sides of the first current collector 211.

[0071] Understandable, such as Figure 4 It is shown that when the first electrode piece 21 is provided with multiple first protrusions 212, the multiple first protrusions 212 can be bent toward the fifth direction V and welded to each other. The welding of multiple first protrusions 212 to each other can shorten the path of electron movement, thereby reducing the internal resistance of the electrode assembly 20.

[0072] In some embodiments, the electrochemical device 100 further includes a first insulating member 40. The first insulating member 40 is adhered to the first protrusions 212 on the outermost sides of the electrode assembly 20 along the fifth direction V. The first insulating member 40 is adhered to the surface of the electrode assembly 20. The first insulating member 40 can reduce the risk of burrs on the surface of the first protrusions 212 being directly exposed after welding, and reduce the risk of burrs piercing the housing 10. In this embodiment, the first insulating member 40 is insulating tape. In other embodiments, the first insulating member 40 can also be other insulating components, such as insulating hot melt adhesive.

[0073] In some embodiments, the first pole piece 21 is a negative pole piece, and the first current collector 211 is a copper foil, which has good conductivity and strength; the thickness of the first current collector 211 ranges from 0.5 μm to 6 μm, which is conducive to improving energy density. It should be understood that the first pole piece 21 is not limited to copper foil, and it can also be other conductive metals. In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 5 μm. In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 4 μm. In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 3 μm. In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 2 μm. In some embodiments, the thickness of the first current collector ranges from 0.5 μm to 1 μm.

[0074] The applicant of this application has found that the first protrusion of the electrode is easily folded during the process of winding around the roller. When the folded first protrusion is rolled into the electrode assembly 20 and is located between electrode sheets of different polarities, the burrs generated by the first protrusion during die-cutting will pierce the isolation membrane 23, thereby posing a safety hazard and affecting the manufacturing efficiency of the electrode assembly.

[0075] In order to solve the problem that the first convex portion of the pole piece is easily folded during the winding process, the embodiment of the present application provides a pole piece, specifically as follows Figure 5 Shown, Figure 5 FIG. 2 shows a simplified structural diagram of the first pole piece 21 before being wound, that is, the first pole piece 21 is in an unfolded state. Figure 5 Although the number of the first protrusions 212 shown in the figure is three, the number of the first protrusions 212 of the first pole piece 21 is not limited to three, and the specific number of the first protrusions 212 can be set according to actual needs. The structure of the first pole piece 21 is as follows:

[0076] The first electrode sheet 21 includes a first current collector 211 , a first protrusion 212 , and a first active material layer 213 . The first active material layer 213 is disposed on a surface of the first current collector 211 . The first protrusion 212 is formed by extending from the first current collector 211 along a first direction X.

[0077] When viewed from the second direction Z, the first current collector 211 includes a first end edge 2111, a second end edge 2112, a first winding starting edge 2113, and a first winding ending edge 2114. The first end edge 2111 and the second end edge 2112 are arranged opposite each other. The two ends of the first winding starting edge 2113 are respectively connected to the first end of the first end edge 2111 and the first end of the second end edge 2112. The two ends of the first winding ending edge 2114 are respectively connected to the second end of the first end edge 2111 and the second end of the second end edge 2112. The first winding starting edge 2113 is the starting edge when the first pole piece 21 is wound, and the first winding ending edge 2114 is the ending edge when the first pole piece 21 is wound. The second direction Z is perpendicular to both the surface of the first protrusion 212 and the first direction X.

[0078] In some embodiments, when viewed from the second direction Z, the first protrusion 212 has a first side 2121, a second side 2122, and a third side 2123. The first side 2121 and the second side 2122 are disposed opposite each other. One end of the third side 2123 is connected to one end of the first side 2121, and the other end of the third side 2123 is connected to one end of the second side 2122. The other end of the first side 2121 is connected to the first end side 2111, and the other end of the second side 2122 is connected to the first end side 2111. An angle α between the first side 2121 and the first end side 2111 in the third direction Y satisfies the following: 25°≤α≤65°.

[0079] The following table shows the processing results when the first protrusion 212 of the first pole piece 21 is wound at different angles α. The number of processing test samples is 3000. The requirement is that the proportion of folding of the first protrusion 212 is less than 10% to be qualified. The results are as follows:

[0080] Table 1 Experimental table of the folding of the first convex part at different angles α

[0081]

[0082] It can be seen from Table 1 that when the angle α takes different values, the proportion of the first protrusion 212 being folded is also different, and when the angle α is in the range of 25° to 65°, the number of samples with the first protrusion 212 being folded decreases, and the proportion of the first protrusion 212 being folded drops to within the qualified range, that is, when the angle α is in the range of 25° to 65°, it is beneficial to reduce the risk of the first protrusion 212 being folded, and continuing to reduce α has no significant effect on further improving the folding, but will increase manufacturing costs, reduce the difficulty and reliability of connecting the first protrusion 212 with other components, and there may also be a risk of the first protrusion entering the winding bending zone during the winding process.

[0083] In some embodiments, the intersection of the other end of the first side 2121 and the first end side 2111 is a first endpoint M1, the intersection of the other end of the second side 2122 and the first end side 2111 is a second endpoint M2, the intersection of one end of the third side 2123 and one end of the first side 2121 is a third endpoint M3, and the intersection of the other end of the third side 2123 and the second side 2122 is a fourth endpoint M4. A direction perpendicular to both the first direction X and the second direction Z is a third direction Y. Along the third direction Y, the distance between the first endpoint M1 and the second endpoint M2 is L2, and the distance between the third endpoint M3 and the fourth endpoint M4 is L1, satisfying the relationship: L2-85.8≤L1≤L2-4.7.

[0084] In some embodiments, along the first direction X, a vertical distance between the third side 2123 and the first end side 2111 is H, and a value range of H is 5 mm to 20 mm.

[0085] In some embodiments, L1 and L2 satisfy the relationship: L1 = L2 - 2 × H × The angle α satisfies the relationship: 25°≤ ≤65°.

[0086] In some embodiments, as Figure 5 As shown, the first side 2121 and the second side 2122 are both straight sides. Figure 6-15 As shown, the first side 2121 includes a first connecting segment 21211 and a second connecting segment 21212, wherein the first connecting segment 21211 is connected to the third side 2123, and the second connecting segment 21212 is connected to the first end side 2111. The connection point between the first connecting segment 21211 and the second connecting segment 21212 is point N1. The first connecting segment 21211 and the second connecting segment 21212 can have different shapes, as follows:

[0087] (1) If Figure 6 and Figure 7 As shown, the first connecting section 21211 and the second connecting section 21212 are both arc-shaped, and the first connecting section 21211 is convexly arranged along the first direction X, and the second connecting section 21212 is concavely arranged along the first direction X;

[0088] In some embodiments, the first connecting segment 21211 is shaped like a partial arc of an ellipse, and the second connecting segment 21212 is shaped like an arc.

[0089] (2) If Figure 8 and Figure 9 As shown, the first connecting segment 21211 is straight, the second connecting segment 21212 is arc-shaped, and the second connecting segment 21212 is concavely arranged along the first direction X; in some embodiments, the second connecting segment 21212 is shaped like a partial arc of an ellipse.

[0090] (3) Please combine Figure 10-13 As shown, the first connecting segment 21211 is arc-shaped, the second connecting segment 21212 is straight-line, and the first connecting segment 21211 is protruding along the first direction X; in some embodiments, the first connecting segment 21211 is arc-shaped.

[0091] (4) If Figure 14 and Figure 15 As shown, the first connecting segment 21211 includes a first arcuate portion 21211a and a first straight portion 21211b, the first straight portion 21211b is connected to the second connecting segment 21212, the first arcuate portion 21211a is connected to the third side 2123, the connection point between the first arcuate portion 21211a and the first straight portion 21211b is point K1, the second connecting segment 21212 is arc-shaped, the second connecting segment is concavely arranged along the first direction X, and the first arcuate portion 21211a is convexly arranged along the first direction X.

[0092] In some embodiments, the first arc portion 21211a is shaped like a partial arc of an ellipse, and the second connecting segment 21212 is shaped like a circular arc. Figure 6-15 The second side 2122 includes a third connecting segment 21221 and a fourth connecting segment 21222, wherein the third connecting segment 21221 is connected to the third side 2123, and the fourth connecting segment 21222 is connected to the first end side 2111. The connection point between the third connecting segment 21221 and the fourth connecting segment 21222 is point N2. The third connecting segment 21221 and the fourth connecting segment 21222 can have different shapes, as follows:

[0093] (1) If Figure 6 and Figure 7 As shown, the third connecting segment 21221 and the fourth connecting segment 21222 are both arc-shaped, and the third connecting segment 21221 is convexly arranged along the first direction X, and the fourth connecting segment 21222 is concavely arranged along the first direction X;

[0094] In some embodiments, the third connecting segment 21221 is shaped like a partial arc of an ellipse, and the fourth connecting segment 21222 is shaped like a circular arc.

[0095] (2) If Figure 8 and Figure 9 As shown, the third connecting segment 21221 is straight, the fourth connecting segment 21222 is arc-shaped, and the fourth connecting segment 21222 is concavely arranged along the first direction X; in some embodiments, the shape of the fourth connecting segment 21222 is a partial arc of an ellipse.

[0096] (3) Please combine Figure 10-13 The third connecting segment 21221 is arc-shaped, the fourth connecting segment 21222 is straight-line, and the third connecting segment 21221 is protruding along the first direction X; in some embodiments, the third connecting segment 21221 is arc-shaped.

[0097] (4) If Figure 14 and Figure 15 As shown, the third connecting segment 21221 includes a second arc-shaped portion 21221a and a second straight portion 21221b, the second straight portion 21221b is connected to the fourth connecting segment 21222, the second arc-shaped portion 21221a is connected to the third side 2123, the connection point between the second arc-shaped portion 21221a and the second straight portion 21221b is point K2, the fourth connecting segment 21222 is arc-shaped, the fourth connecting segment 21222 is concavely arranged along the first direction X, and the second arc-shaped portion 21221a is convexly arranged along the first direction X.

[0098] In some embodiments, the second arc portion 21221a is shaped like a partial arc of an ellipse, and the fourth connecting segment 21222 is shaped like a circular arc.

[0099] It is understood that during the processing, the first electrode 21 moves the same amount of displacement on the workbench of the laser cutting equipment, and designing the shapes of the first connecting segment 21211, the second connecting segment 21212, the third connecting segment 21221, and the fourth connecting segment 21222 into different shapes will further help improve production efficiency. It is understood that when observed from the second direction Z, the first side 2121 and the second side 2122 can be symmetrically arranged at the two ends of the third side 2123, or the first side 2121 and the second side 2122 can be asymmetrically arranged at the two ends of the third side 2123. The first connecting segment 21211, the second connecting segment 21212, the third connecting segment 21221, and the fourth connecting segment 21222 have different shapes, so that the first protrusion 212 of the electrode assembly 20 can be bent to meet different packaging requirements, and has a wide range of applications.

[0100] In some embodiments, as Figure 5 As shown, the first side 2121 and the second side 2122 are symmetrically arranged along a first axis EE', and the first axis EE' passes through the midpoint of the third side 2123 along the first direction X. In this way, the first side 2121 and the second side 2122 both have the same angle with the first end side, which can further reduce the risk of the first protrusion 212 being bent during the winding process.

[0101] In some embodiments, as Figure 16 and Figure 17 As shown, the first pole piece 21 further includes a first layer 214, which is made of an insulating material and is disposed on the first surface of the first protrusion 212. The first layer 214 can shield burrs on the first protrusion 212, reducing the risk of direct exposure of burrs on the surface of the first protrusion 212. In some embodiments, the first layer 214 is connected to the first end edge 2111, which can improve the quality of the first protrusion 212 near the first end edge 2111, enhance stability during the winding process, improve resistance to centrifugal force, and reduce the risk of folding. In other embodiments, the first pole piece 21 further includes a second layer 215, which is provided on the second surface of the first protrusion 212, and the first surface of the first layer 214 and the second surface of the first layer 214 are two surfaces arranged opposite to each other. The second layer 215 is made of an insulating material. The second layer 215 can also reduce the risk of direct exposure of burrs on the surface of the first protrusion 212, and reduce the risk of burrs on the surface of the first protrusion 212 piercing the isolation membrane 23, which is beneficial to improving the safety of the electrochemical device 100.

[0102] The insulating material includes at least one of aluminum oxide, boehmite, silicon dioxide, titanium oxide, magnesium oxide, zirconium oxide, calcium oxide, or a ceramic coating. Of course, the insulating material may also be other materials and is not limited to those listed in this embodiment. It is understood that the insulating materials mentioned in this embodiment are all existing insulating materials and will not be described in detail.

[0103] It should be noted that the multiple first protrusions 212 of the first pole piece 21 are all integrally formed with the first current collector 211. They can be directly stamped on the first pole piece 21 through a blanking process, or the first pole piece 21 is formed by laser cutting. Of course, the first protrusions 212 can also be integrally formed with the first current collector 211 through other methods. In this embodiment, the multiple first protrusions 212 are integrally formed with the first current collector 211 through laser cutting. The multiple first protrusions 212 are all located on the same side of the first current collector 211 and are spaced apart.

[0104] It should be understood that although the above embodiment is an introduction to the structure of the first pole piece 21, the structure of the first pole piece 21 is also applicable to the second pole piece 22, as follows:

[0105] Please combine Figure 2 、 Figure 18-19 , Figure 18 is Figure 2 The schematic diagram obtained after cutting along the straight line PP', Figure 19 for Figure 18 A schematic diagram of the second pole piece 22 after expansion, as shown in FIG. Figure 19 As shown, the second pole piece 22 includes a second current collector 221, a second protrusion 222, and a second active material layer 223. The second protrusion 222 extends from the second current collector 221 along the first direction X. At least one of the two opposing surfaces of the second current collector 221 is coated with the second active material layer 223. That is, the second active material layer 223 can be provided on one surface of the second current collector 221, or the second active material layer 223 can be provided on two opposing surfaces of the second current collector 221. The specific configuration can be based on actual needs. The second protrusion 222 is connected to the second pole tab 32 of the pole tab assembly 30, either directly or indirectly. In this embodiment, the second protrusion 222 is directly connected to the second pole piece 32.

[0106] In some embodiments, there are multiple second protrusions 222, each extending from the second current collector 221 along the first direction X. The multiple second protrusions 222 can be disposed on the same side of the second current collector 221, or on opposite sides of the second current collector 221. When the second pole piece 22, the first pole piece 21, and the separator 23 are wound, the multiple second protrusions 222 are bent and welded to each other, thereby shortening the path for electron movement and facilitating reduced internal resistance of the electrochemical device 100.

[0107] like Figure 19 As shown, when viewed from the second direction Z, the second current collector 221 includes a third end edge 2211, a fourth end edge 2212, a second winding starting edge 2213, and a second winding ending edge 2214. The third end edge 2211 is disposed opposite the fourth end edge 2212. The two ends of the second winding starting edge 2213 are respectively connected to the first end of the third end edge 2211 and the first end of the fourth end edge 2212. The two ends of the second winding ending edge 2214 are respectively connected to the second end of the third end edge 2211 and the second end of the fourth end edge 2212. The second winding starting edge 2213 is the starting edge when the second pole piece 22 is wound, and the second winding ending edge 2214 is the ending edge when the second pole piece 22 is wound. The second direction Z is perpendicular to both the surface of the second protrusion 222 and the first direction X.

[0108] In some embodiments, when viewed from the second direction Z, the second protrusion 222 has a fourth side 2221, a fifth side 2222, and a sixth side 2223. The fourth side 2221 is disposed opposite the fifth side 2222. One end of the sixth side 2223 is connected to one end of the fourth side 2221, the other end of the sixth side 2223 is connected to one end of the fifth side 2222, the other end of the fourth side 2221 is connected to the third end side 2211, and the other end of the fifth side 2222 is connected to the third end side 2211. Along the first direction X, a vertical distance H' is defined between the sixth side 2223 and the third end side 2211, and the value of H' ranges from 5 mm to 20 mm.

[0109] The intersection of the other end of the fourth side 2221 and the third side 2211 is a first endpoint M5, the intersection of the other end of the fifth side 2222 and the third side 2211 is a second endpoint M6, the intersection of one end of the sixth side 2223 and one end of the fourth side 2221 is a third endpoint M7, and the intersection of the other end of the sixth side 2223 and the fifth side 2222 is a fourth endpoint M8. A direction perpendicular to both the first direction X and the second direction Z is a third direction Y. Along the third direction Y, the distance between the first endpoint M5 and the second endpoint M6 is L4, and the distance between the third endpoint M7 and the fourth endpoint M8 is L3, satisfying the relationship: L4-85.8≤L3≤L4-4.7.

[0110] In some embodiments, the included angle between the fourth side 2221 and the third end side 2211 in the third direction Y is β, and L3 and L4 satisfy the relationship: L3=L4-2×H× In some embodiments, the angle β satisfies the relationship: 25°≤ ≤65°.

[0111] In some embodiments, as Figure 19 As shown, the fourth side 2221 and the fifth side 2222 are both straight sides. Figure 20-29 As shown, the fourth side 2221 includes a fifth connecting segment 22211 and a sixth connecting segment 22212 connected to each other. The fifth connecting segment 22211 is connected to the sixth side 2223, and the sixth connecting segment 22212 is connected to the third end side 2211. The connection point between the fifth connecting segment 22211 and the sixth connecting segment 22212 is point N3. The fifth connecting segment 22211 and the sixth connecting segment 22212 can have different shapes, as follows:

[0112] (1) If Figure 20 and Figure 21 As shown, the fifth connecting segment 22211 and the sixth connecting segment 22212 are both arc-shaped, and the fifth connecting segment 22211 is convexly arranged along the first direction X, and the sixth connecting segment 22212 is concavely arranged along the first direction X;

[0113] In some embodiments, the fifth connecting segment 22211 is shaped like a partial arc of an ellipse, and the sixth connecting segment 22212 is shaped like an arc.

[0114] (2) If Figure 22 and Figure 23As shown, the fifth connecting segment 22211 is straight, the sixth connecting segment 22212 is arc-shaped, and the sixth connecting segment 22212 is concavely arranged along the first direction X; in some embodiments, the shape of the sixth connecting segment 22212 is a partial arc of an ellipse.

[0115] (3) Please combine Figures 24-27 The fifth connecting segment 22211 is arc-shaped, the sixth connecting segment 22212 is straight-line, and the fifth connecting segment 22211 is protruding along the first direction X; in some embodiments, the fifth connecting segment 22211 is arc-shaped.

[0116] (4) If Figure 28 and Figure 29 As shown, the fifth connecting segment 22211 includes a third arcuate portion 22211a and a third straight portion 22211b. The third straight portion 22211b is connected to the sixth connecting segment 22212. The third arcuate portion 22211a is connected to the sixth side 2223. The connection point between the third arcuate portion 22211a and the third straight portion 22211b is point K3. The sixth connecting segment 22212 is arc-shaped and is concavely disposed along the first direction X. The third arcuate portion 22211a is convexly disposed along the first direction X. In some embodiments, the third arcuate portion 22211a is shaped like a partial arc of an ellipse, and the sixth connecting segment 22212 is shaped like a circular arc.

[0117] Please refer again Figure 20-29 The fifth side 2222 includes a seventh connecting segment 22221 and an eighth connecting segment 22222, wherein the seventh connecting segment 22221 is connected to the sixth side 2223, and the eighth connecting segment 22222 is connected to the third end side 2211. The connection point between the seventh connecting segment 22221 and the eighth connecting segment 22222 is point N4. The seventh connecting segment 22221 and the eighth connecting segment 22222 can have different shapes, as follows:

[0118] (1) If Figure 20 and Figure 21 As shown, the seventh connecting segment 22221 and the eighth connecting segment 22222 are both arc-shaped, and the seventh connecting segment 22221 is convexly arranged along the first direction X, and the eighth connecting segment 22222 is concavely arranged along the first direction X;

[0119] In some embodiments, the seventh connecting segment 22221 is shaped like a partial arc of an ellipse, and the eighth connecting segment 22222 is shaped like an arc.

[0120] (2) If Figure 22 and Figure 23 As shown, the seventh connecting segment 22221 is straight, the eighth connecting segment 22222 is arc-shaped, and the eighth connecting segment 22222 is concavely arranged along the first direction X; in some embodiments, the shape of the eighth connecting segment 22222 is a partial arc of an ellipse.

[0121] (3) Please combine Figures 24-27 The seventh connecting segment 22221 is arc-shaped, the eighth connecting segment 22222 is straight-line, and the seventh connecting segment 22221 is protruding along the first direction X; in some embodiments, the seventh connecting segment 22221 is arc-shaped.

[0122] (4) If Figure 28 and Figure 29 As shown, the seventh connecting segment 22221 includes a fourth arcuate portion 22221a and a fourth straight portion 22221b. The fourth straight portion 22221b is connected to the eighth connecting segment 22222. The fourth arcuate portion 22221a is connected to the sixth side 2223. The connection point between the fourth arcuate portion 22221a and the fourth straight portion 22221b is point K4. The eighth connecting segment 22222 is arc-shaped and is concavely arranged along the first direction X. The fourth arcuate portion 22221a is convexly arranged along the first direction X. In some embodiments, the fourth arcuate portion 22221a is shaped like a partial arc of an ellipse, and the eighth connecting segment 22222 is shaped like a circular arc.

[0123] It can be understood that during the processing, the second pole piece 22 moves the same displacement on the workbench of the laser cutting equipment, and designing the shapes of the fifth connecting segment 22211, the sixth connecting segment 22212, the seventh connecting segment 22221 and the eighth connecting segment 22222 into different shapes will help improve production efficiency.

[0124] It can be understood that, when observed from the second direction Z, the fourth side 2221 and the fifth side 2222 can be symmetrically arranged at both ends of the sixth side 2223, and the fourth side 2221 and the fifth side 2222 can also be asymmetrically arranged at both ends of the sixth side 2223.

[0125] In some embodiments, please combine Figure 30 and Figure 31The second pole piece 22 further includes a third layer 224, which is provided on the first surface of the second protrusion 222. The third layer 224 is made of an insulating material. The third layer 224 can reduce the risk of direct exposure of burrs on the surface of the second protrusion 222. In some embodiments, the second pole piece 22 further includes a fourth layer 225, which is provided on the second surface of the second protrusion 222. The fourth layer 225 is also made of an insulating material. The fourth layer 225 can reduce the risk of direct exposure of burrs on the surface of the second protrusion 222. The first surface of the second protrusion 222 and the second surface of the second protrusion 222 are two surfaces arranged opposite to each other.

[0126] In some embodiments, please refer again to Figure 18 The electrochemical device 100 also includes a second insulating tape 50. Along the second direction Z, the second protrusions 222 located on the outermost sides of the electrode assembly 20 are both pasted with the second insulating tape 50. The second insulating tape 50 is pasted on the surface of the electrode assembly 20. The second insulating tape 50 can reduce the risk of burrs on the surface of the second protrusion 222 being directly exposed after welding, and reduce the risk of burrs piercing the shell 10.

[0127] The electrochemical device 100 provided in an embodiment of the present application includes an electrode assembly 20. The electrode assembly 20 includes a first electrode sheet 21. The first electrode sheet 21 includes a first current collector 211 and a first protrusion 212 extending from the first current collector 211 along a first direction X. A second direction Z is defined as a direction perpendicular to the first surface of the first protrusion 212 and the first direction X, and a third direction Y is defined as a direction perpendicular to both the first and second directions. As viewed from the second direction Z, the first current collector 211 includes a first end edge 2111. The first protrusion 212 includes a first edge 2121, a second edge 2122, and a third edge 2123. The first edge 2121 is disposed opposite the second edge 2122. One end of the third edge 2123 is connected to one end of the first edge 2121, and the other end of the third edge 2123 is connected to one end of the second edge 2122. The other end of the first edge 2121 is connected to the first end edge 2111, and the other end of the second edge 2122 is connected to the first end edge 2111. The angle between the first side and the first end side in the third direction is , meeting: 25°≤ ≤65°. Thus, when the first protrusion 212 satisfies the above structure, the connection between the first protrusion 212 and the first current collector 211 has appropriate strength, reducing the risk of the first protrusion 212 being folded relative to the first current collector 211 during the winding process of the first pole piece 21. This reduces the risk of burrs on the first protrusion 212 piercing the separator 23 after the folding of the first protrusion 212, thereby reducing the risk of a short circuit or lithium deposition caused by burrs on the first protrusion 212. This is beneficial to improving the safety of the electrochemical device 100.

[0128] like Figure 32 As shown, another embodiment of the present application provides a battery module 200, comprising the electrochemical device 100 of the above embodiment. There are multiple electrochemical devices 100, which can be connected in series or in parallel according to actual needs.

[0129] like Figure 33 As shown, another embodiment of the present application provides an electronic device 300, which includes the electrochemical device 100 in the above embodiment. The electrochemical device 100 is used to provide electrical energy for the electronic device 300.

[0130] The above description is only an implementation method of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the description and drawings of this application, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An electrochemical device, characterized in that The electrode assembly includes an electrode sheet that is wound, the electrode sheet includes a first current collector and a first protrusion, and the first protrusion extends from the first current collector along a first direction; defining a thickness direction of the first protrusion as a second direction, the second direction being perpendicular to the first direction, and a direction perpendicular to the first direction and the second direction being a third direction; Observed from the second direction, the first current collector has a first end edge, the first protrusion has a first edge, a second edge and a third edge, the first edge and the second edge are arranged opposite to each other along the third direction, the first edge connects the third edge and the first end edge, and the second edge connects the first edge and the first end edge; in the first direction, the extension line of the first edge intersects with the extension line of the second edge, and the acute angle formed by the first edge and the first end edge is α, 25°≤α≤65°.

2. The electrochemical device according to claim 1, wherein An acute angle formed by the second side and the first end side is β, and 25°≤β≤65°.

3. The electrochemical device according to claim 2, characterized in that The intersection of the first side and the first end side is a first endpoint, and the intersection of the second side and the first end side is a second endpoint; In the third direction, the distance between the first endpoint and the second endpoint is L2, the length of the third side is L1, and L2-85.8≤L1≤L2-4.

7.

4. The electrochemical device according to any one of claims 1 to 3, characterized in that The first side includes a first connecting segment and a second connecting segment connected to each other, the first connecting segment is connected to the third side, and the second connecting segment is connected to the first end side, and the electrochemical device satisfies any one of the following conditions: The first connecting section and the second connecting section are both arc-shaped, the first connecting section is convex along the first direction, and the second connecting section is concave along the first direction; The first connecting section is in a straight line shape, the second connecting section is in an arc shape, and the second connecting section is concavely arranged along the first direction; The first connecting section is arc-shaped, the second connecting section is straight-line, and the first connecting section is protruding along the first direction; The first connecting section includes a first arc-shaped portion and a first straight portion connected to each other, the first arc-shaped portion is connected to the third side, the first straight portion is connected to the second connecting section, the first arc-shaped portion is protruding along the first direction, the second connecting section is arc-shaped, and the second connecting section is concave along the first direction.

5. The electrochemical device according to any one of claims 1 to 3, characterized in that The second side includes a third connecting segment and a fourth connecting segment connected to each other, the third connecting segment is connected to the third side, and the fourth connecting segment is connected to the first end side, and the electrochemical device satisfies any one of the following conditions: The third connecting section and the fourth connecting section are both arc-shaped, the third connecting section is convex along the first direction, and the fourth connecting section is concave along the first direction; The third connecting segment is in a straight line shape, the fourth connecting segment is in an arc shape, and the third connecting segment is concavely arranged along the first direction; The third connecting segment is arc-shaped, the fourth connecting segment is straight-line, and the third connecting segment is protruding along the first direction; The third connecting segment includes a second arc-shaped portion and a second straight portion connected to each other, the second arc-shaped portion is connected to the third side, the second straight portion is connected to the fourth connecting segment, the second arc-shaped portion is protruding along the first direction, the third connecting segment is arc-shaped, and the fourth connecting segment is concave along the first direction.

6. The electrochemical device according to claim 1, wherein The first pole piece includes a plurality of first protrusions, and the plurality of first protrusions are distributed along the third direction.

7. The electrochemical device according to claim 1, wherein The first electrode sheet is a negative electrode sheet, the first current collector is a copper foil, and the thickness of the first current collector ranges from 0.5 μm to 6 μm.

8. The electrochemical device according to claim 1, wherein The first side and the second side are symmetrically arranged along a first axis, and the first axis passes through a midpoint of the third side along the first direction.

9. The electrochemical device according to claim 1, wherein A first layer containing insulating material is provided on the first protrusion, and the first layer is connected to the first end edge.

10. An electronic device, characterized in that: The electrochemical device comprises the electrochemical device according to any one of claims 1 to 9.

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