Pole piece, electrode assembly, battery cell, and electric device

Abstract

The utility model relates to a kind of pole piece, electrode assembly, battery monomer and electric device, comprising: current collector, including main body part and the convex part of the convex main body part setting;Active material layer, along the thickness direction of current collector, at least one side surface of main body part is set;The region of convex part is not set active material layer and forms tab;Active material layer has first area and second area on main body part, along first direction, first area is close to convex part relative to second area, first direction is the direction of main body part to convex part;Along the thickness direction, at least one side surface of tab has first reinforcing portion, the active material layer of at least one side surface of main body part has second reinforcing portion, second reinforcing portion is located the surface of first area away from main body part.The setting of second reinforcing portion, equivalent to increase the length of first reinforcing portion along first direction, further increase the tensile strength of tab, can reduce the risk of tab collapse, thereby reduce the risk of tab folding.

Description

Technical Field

[0001] This utility model relates to the field of new energy technology, and in particular to an electrode sheet, an electrode assembly, a battery cell, and an electrical device. Background Technology

[0002] As the demand for energy density and power of power batteries from new energy vehicles continues to increase, battery cell design is trending towards larger sizes and more tabs. Tabs are formed by protruding areas extending outward from the current collector. When the tabs are large, they are prone to folding during assembly.

[0003] Folding the tabs will have many adverse effects. For example, folding the tabs will cause the tabs to not be effectively connected or in contact with the current collector body area and / or external terminals, resulting in increased internal resistance; or, folding the tabs may insert into the core, causing a short circuit in the cell or lithium plating.

[0004] To address the tab folding issue, traditional technologies often focus on optimizing tab thickness or using tab adhesive. However, increasing tab thickness sacrifices battery energy density, while tab adhesive manufacturing is costly and offers limited improvement. Utility Model Content

[0005] Therefore, it is necessary to provide an electrode sheet, electrode assembly, battery cell, and power supply device that can reduce the risk of electrode tabs being easily folded, in order to address the problem of electrode tabs being easily folded.

[0006] On the one hand, this application provides an electrode sheet comprising:

[0007] The current collector includes a main body and a protrusion that protrudes from the main body;

[0008] An active material layer is disposed on at least one side surface of the main body along the thickness direction of the current collector; the area of ​​the protrusion where the active material layer is not disposed forms an electrode tab;

[0009] The active material layer has a first region and a second region located on the main body portion. Along a first direction, the first region is closer to the protrusion relative to the second region. The first direction is the direction from the main body portion to the protrusion.

[0010] Along the thickness direction, at least one side surface of the tab has a first reinforcing portion, and at least one side surface of the main body has an active material layer with a second reinforcing portion, the second reinforcing portion being located on the surface of the first region away from the main body.

[0011] In one embodiment, along the thickness direction, the first reinforcing portion and the second reinforcing portion are both located on the same side surface of the electrode.

[0012] In one embodiment, along the thickness direction, one side surface of the tab is recessed and the other side surface is correspondingly protruding to form the first reinforcing portion; one side surface of the first region is recessed and the other side surface is correspondingly protruding to form the second reinforcing portion.

[0013] In one embodiment, the first reinforcing portion and the second reinforcing portion are connected to each other to form a reinforcing portion along the first direction.

[0014] In one embodiment, the cross-sectional shape of the reinforcing part is an elongated strip extending along the first direction.

[0015] In one embodiment, the depth of the recess in the reinforcement along the thickness direction decreases in a direction opposite to the first direction.

[0016] In one embodiment,

[0017] The reinforcing part has a first included angle θ with the first direction, where 0°≤θ≤20°.

[0018] In one embodiment, the first reinforcing portion and the second reinforcing portion are spaced apart along the first direction.

[0019] In one embodiment, the first reinforcing part has a cross-sectional shape that is an elongated strip extending along the first direction, and the second reinforcing part has a circular cross-sectional shape.

[0020] In one embodiment, the first reinforcing portion has a first bottom wall and a first side wall that are interconnected, and the first bottom wall and the first side wall have a smooth transition.

[0021] and / or

[0022] The second reinforcing part has a second bottom wall and a second side wall that are connected to each other, and there is a smooth transition between the second bottom wall and the second side wall.

[0023] In one embodiment, the feature is:

[0024] Along the thickness direction, the protrusion has a first thickness c, the first reinforcing portion has a first depth recess H1, the sum of the thicknesses of the main body and the entire first region is a second thickness T2, and the second reinforcing portion has a second recess depth H2; wherein,

[0025] H1 = (1-100)c;

[0026] And / or, H2 = (0.05-1)T2;

[0027] And / or, H2 < H1;

[0028] And / or, 5μm≤H1≤500μm;

[0029] And / or, 5μm≤H2≤100μm.

[0030] In one embodiment, the feature is:

[0031] The number of the first reinforcing parts is multiple, and the cross-sectional shape of each first reinforcing part is an elongated strip extending along the first direction. Each pair of adjacent first reinforcing parts has a third spacing D1 along the second direction. The first direction, the thickness direction and the second direction intersect each other.

[0032] Each of the first reinforcing portions has a first recess depth H1 along the thickness direction, the protrusion has a third height a along the first direction, the protrusion has a first thickness c along the thickness direction, and the protrusion has a first width b along the second direction;

[0033] H1 / D1 = k*a / (b*c);

[0034] Wherein, 5μm≤H1≤500μm, 1mm≤D1≤10mm, 1*10 -7 ≤k≤0.08.

[0035] In one embodiment, all of the protrusions serve as the electrode tabs;

[0036] or

[0037] The protrusion includes a connecting portion and the electrode tab arranged sequentially along the first direction. The connecting portion connects the main body portion and the electrode tab, and the active material layer is also disposed on the connecting portion.

[0038] In one embodiment, the second reinforcing portion extends to the connecting portion.

[0039] In one embodiment, along the first direction, the second reinforcement has a first edge away from the protrusion, and the first region has a second edge close to the protrusion;

[0040] Along the first direction, there is a first spacing L1 between the first edge and the second edge, where 1mm≤L1≤10mm.

[0041] In one embodiment, the main body portion has a third edge connected to the protrusion;

[0042] Along the first direction, the first edge and the third edge have a second distance L2, where 1mm ≤ L2 ≤ 10mm;

[0043] And / or, L1 = L2.

[0044] In one embodiment,

[0045] Along the second direction, there is a third spacing D1 between every two adjacent first reinforcing parts, and a fourth spacing D2 between every two adjacent second reinforcing parts; the second direction, the thickness direction, and the first direction intersect each other; wherein,

[0046] D2≥D1;

[0047] And / or, 1mm≤D1≤10mm;

[0048] And / or, 1mm≤D2≤20mm.

[0049] In one embodiment, the thickness of the first region is less than the thickness of the second region.

[0050] On the other hand, this application also provides an electrode assembly, including the electrode sheet as described above.

[0051] Furthermore, this application provides a battery cell that includes the electrode sheet as described above, or the electrode assembly as described above.

[0052] In another aspect, this application provides an electrical device including the aforementioned battery cell.

[0053] Compared with the prior art, this application has the following beneficial effects:

[0054] In the aforementioned electrode sheets, electrode assemblies, battery cells, and power devices, since the extension length of the reinforcing portion along the first direction is positively correlated with the tensile strength and stress dispersion capability of the electrode tab, by providing a first reinforcing portion on at least one side surface of the electrode tab and a second reinforcing portion on the surface of the active material layer of at least one side surface of the current collector body facing away from the body, the length of the first reinforcing portion along the first direction is effectively increased, further increasing the tensile strength of the electrode tab. Compared to providing only the first reinforcing portion on the electrode tab, this reduces the risk of electrode tab collapse, thereby reducing the risk of electrode tab folding. Compared to optimizing the electrode tab thickness, the provision of the first and second reinforcing portions does not lead to an increase in electrode tab thickness, and therefore does not sacrifice battery energy density. Compared to using electrode tab adhesive to improve electrode tab folding, the process cost is low and the effect of improving electrode tab folding is better. On the other hand, providing a second reinforcing portion on the surface of the first region facing away from the body on at least one side enhances the strength of the first region and also reduces the risk of electrode wrinkling. Attached Figure Description

[0055] 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 without creative effort.

[0056] Figure 1 This is a structural diagram of an electrode sheet provided in an embodiment of this application;

[0057] Figure 2 for Figure 1 The diagram shows the structure of the current collector for the electrode plate shown.

[0058] Figure 3 for Figure 1 Enlarged view of point A on the electrode shown;

[0059] Figure 4 This is a structural diagram of an electrode provided in another embodiment of this application;

[0060] Figure 5 for Figure 4 Enlarged view of point A on the electrode shown;

[0061] Figure 6 This is a structural diagram of an electrode sheet provided in another embodiment of this application;

[0062] Figure 7 for Figure 6 Enlarged view of point C on the electrode shown;

[0063] Figure 8 A cross-sectional view of an electrode sheet provided in another embodiment of this application;

[0064] Figure 9 This is a structural diagram of an electrode provided in another embodiment of this application;

[0065] Figure 10 for Figure 9 A cross-sectional view of electrode B shown in the diagram;

[0066] Figure 11 A longitudinal cross-sectional view of an electrode sheet provided in another embodiment of this application;

[0067] Figure 12 A longitudinal cross-sectional view of an electrode sheet provided in yet another embodiment of this application;

[0068] Figure 13 This is a structural diagram of an electrode provided in another embodiment of this application;

[0069] Figure 14 This is a structural diagram of an electrode sheet provided in another embodiment of this application;

[0070] Figure 15 This is a structural diagram of an electrode sheet provided in another embodiment of this application;

[0071] Figure 16 This is a structural diagram of an electrode sheet provided in another embodiment of this application;

[0072] Figure 17 This is a structural diagram of an electrode provided in another embodiment of this application;

[0073] Figure 18 This is a structural diagram of an electrode sheet provided in another embodiment of this application;

[0074] Figure 19 This is a structural diagram of an electrode sheet provided in another embodiment of this application;

[0075] Figure 20 This is a structural diagram of an electrode sheet provided in another embodiment of this application;

[0076] Figure 21 The structure of an electrode assembly provided in one embodiment of this application.

[0077] Explanation of reference numerals in the attached figures:

[0078] 1000, Electrode assembly; 100, Electrode sheet; 100a, Positive electrode sheet; 100b, Negative electrode sheet; 10, Current collector; 11, Main body; 12, Protrusion; 121, Tab; 122, Connecting part; 20, Active material layer; 21, First region; 211, First sub-region; 212, Second sub-region; 22, Second region; 30, First reinforcing part; 40, Second reinforcing part; 41, Second bottom wall; 42, Second side wall; 50, Boundary line; 60, First edge; 70, Second edge; 80, Third edge; 200, Separator. Detailed Implementation

[0079] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0080] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0081] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0082] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0083] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0084] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0085] See Figure 1 and Figure 2 One embodiment of this application provides an electrode 100, which can be a positive electrode 100a or a negative electrode 100b, and is not limited thereto. The electrode 100 includes a current collector 10, which is typically formed using metal foil. For example, some negative electrode current collectors 10 can be formed using copper foil, while others (such as the negative electrode current collector 10 of a sodium-ion battery) can be formed using aluminum foil. Some positive electrode current collectors 10 can be formed using aluminum foil. Of course, in other embodiments, the type of foil selected for the current collector 10 is not limited.

[0086] Continue reading Figure 2 The current collector 10 includes a main body 11 and a protrusion 12. The protrusion 12 protrudes from the main body 11, that is, the protrusion 12 serves as an extension of the current collector 10 extending outward relative to the main body 11. Optionally, the protrusion 12 protrudes from one side of the main body 11. In other embodiments, the protrusion 12 may also be provided on opposite sides of the main body 11, which is not limited here.

[0087] Continue reading Figure 1 The electrode 100 also includes an active material layer 20, which extends along the thickness direction of the current collector 10. Figure 1 The active material layer 20 is disposed on at least one side surface of the main body 11 (perpendicular to the paper surface). A tab 121 is formed in the area of ​​the protrusion 12 where the active material layer 20 is not disposed. The current collector 10 is used to conduct the current generated by the active material layer 20, and the tab 121 serves as the current output terminal of the current collector 10. For wet-process electrode preparation 100, typically, during the preparation of electrode 100, active materials, binders, conductive agents, and solvents are mixed to form an active slurry, which is then coated onto the current collector 10 to form the active material layer 20. The active material layer 20 is then dried and rolled to form the electrode 100. For dry-process electrode preparation 100, the pre-prepared active material layer 20 is deposited onto the current collector 10 by dry pressing.

[0088] It should be noted that since the thickness direction of the entire electrode 100 is parallel to the thickness direction of the current collector 10, the thickness direction mentioned below refers to the thickness direction of the current collector 10 or the electrode 100.

[0089] Continue reading Figure 1 The active material layer 20 has a first region 21 and a second region 22. Along a first direction, the first region 21 is positioned closer to the protrusion 12 than the second region 22. The first direction is the direction from the main body 11 to the protrusion 12; that is, the first direction is the protrusion direction in which the protrusion 12 protrudes from the main body 11. The first direction intersects the thickness direction; specifically, the first direction is perpendicular to the thickness direction. In some embodiments, when the protrusion 12 protrudes from the main body 11 along the width direction of the current collector 10, the first direction is parallel to the width direction. Figure 1 and Figure 2 The Y-direction is the first direction.

[0090] Continue reading Figure 1 Along the thickness direction, at least one side surface of the tab 121 has a first reinforcing portion 30. The strength of the tab 121 is enhanced by providing the first reinforcing portion 30. Furthermore, along the thickness direction, the active material layer 20 on at least one side surface of the main body 11 has a second reinforcing portion 40, located on the surface of the first region 21 opposite to the main body 11. Specifically, the first region 21 has a first portion facing the tab 121 along a first direction with the second reinforcing portion 40. More specifically, when the electrode 100 has multiple tabs 121, the first region 21 has a first portion facing each tab 121 along the first direction, and each first portion has the second reinforcing portion 40.

[0091] Since the extension length of the reinforcing portion along the first direction is positively correlated with the tensile strength and stress dispersion capability of the tab 121, by providing a first reinforcing portion 30 on at least one side of the tab 121 and providing a second reinforcing portion 40 on the surface of the first region 21 of the active material layer 20 facing away from the main body 11 on at least one side, the length of the first reinforcing portion 30 along the first direction is effectively increased, further increasing the tensile strength of the tab 121. Compared to providing only the first reinforcing portion 30 on the tab 121, the risk of the tab 121 collapsing can be reduced, thereby reducing the risk of the tab 121 folding. Compared to optimizing the thickness of the tab 121, the provision of the first reinforcing portion 30 and the second reinforcing portion 40 does not lead to an increase in the thickness of the tab 121, and therefore does not sacrifice the battery energy density. Compared to using tab adhesive to improve the folding of the tab 121, the process cost is low and the effect of improving the folding of the tab 121 is better. On the other hand, a second reinforcing part 40 is provided on the surface of the first region 21 on at least one side facing away from the main body 11, which enhances the strength of the first region 21 and reduces the risk of wrinkling of the electrode 100.

[0092] It should be noted that in this application, the second reinforcing part 40 is disposed on the surface of the first region 21 facing away from the main body 11. That is, if the surface of the first region 21 that is in contact with the main body 11 is defined as the inner surface, then the second reinforcing part 40 is located on the outer surface of the first region 21. This is because during the preparation of the electrode 100, after the active material is formed on the current collector 10, necessary steps such as drying and rolling are required. Drying is to remove the organic solvent in the active material, and rolling is to reduce the gap between the active materials, shorten the current path, and improve the adhesion between the active material and the current collector 10. In order not to affect the second reinforcing part 40, the second reinforcing part 40 needs to be formed on the outer surface of the first region 21 of the active material layer 20 after the active material layer 20 is formed on the main body 11. If the second reinforcing part 40 is formed on the main body 11 before the active material layer 20 is formed, the second reinforcing part 40 may be flattened during the rolling process, and if the second reinforcing part 40 is flattened, it will not be able to provide reinforcement.

[0093] In some embodiments, see further reference. Figure 1 and see Figure 3 All of the protrusions 12 serve as tabs 121. At this time, the entire protrusion 12 is not provided with an active material layer 20, that is, the active material area will not be cut when the protrusion 12 is formed by die cutting. In this way, the waste of active material can be reduced and resources can be saved.

[0094] In other embodiments, see Figure 4 and Figure 5 The protrusion 12 includes a connecting portion 122 and a tab 121 arranged sequentially along a first direction. The connecting portion 122 connects the main body portion 11 and the tab 121, and the active material layer 20 is also disposed on the connecting portion 122. In this way, when the active material area is cut during die cutting to form the protrusion 12, the generation of burrs can be reduced compared to the case where the active material area is not cut.

[0095] Further reading Figure 5The second reinforcing portion 40 extends to the connecting portion 122. It should be noted that "the second reinforcing portion 40 extends to the connecting portion 122" means that the second reinforcing portion 40 disposed in the first region 21 is also disposed on the surface of the active material layer 20 on the connecting portion 122 facing away from the surface of the connecting portion 122. The second reinforcing portion 40 can extend to the active material layer 20 on the connecting portion 122 in a continuous manner or in a discontinuous manner. When the second reinforcing portion 40 extends to the active material layer 20 on the connecting portion 122 in a continuous manner, the second reinforcing portion 40 located in the first region 21 and the second reinforcing portion 40 located on the active material layer 20 on the connecting portion 122 are connected as one unit. When the second reinforcing portion 40 extends to the active material layer 20 on the connecting portion 122 in a discontinuous manner, the second reinforcing portion 40 located in the first region 21 and the second reinforcing portion 40 located on the active material layer 20 on the connecting portion 122 are spaced apart.

[0096] In some implementations, see further reference. Figure 3 Along the first direction, the first region 21 has a second edge 70 near the protrusion 12, and the main body 11 has a third edge 80 connected to the protrusion 12, with the second edge 70 and the third edge 80 being flush. At this time, the edge of the active material layer 20 on the main body 11 is the edge of the main body 11, and there is no region on the main body 11 near the protrusion 12 where the active material layer 20 is not provided.

[0097] In other embodiments, see [reference] Figure 6 and with Figure 7 The second edge 70 is located inside the third edge 80. At this time, the edge of the active material layer 20 on the main body 11 is located inside the edge of the main body 11, and there is a region on the main body 11 near the protrusion 12 where the active material layer 20 is not provided.

[0098] Continue reading Figure 3 and Figure 7 Along the first direction, the second reinforcing part 40 has a first edge 60 away from the protrusion 12 (the first edge 60 is also the end of the second reinforcing part 40; when there are multiple second reinforcing parts 40, the one whose end of all the second reinforcing parts 40 is farthest from the protrusion 12 is the first edge 60), and there is a first distance L1 between the first edge 60 and the second edge 70, 1mm≤L1≤10mm.

[0099] Specifically, the first distance is obtained as follows: the straight-line distance between the first end face of the second reinforcing part 40 away from the protrusion 12 in the first direction (when one side of the first region 21 is concave and the other side is correspondingly convex or non-convex to form the second reinforcing part 40 (hereinafter, the first end face is the wall surface of the groove of the second reinforcing part 40 away from the protrusion 12 along the first direction) and the second edge 70. If the first end face is not perpendicular to the first direction, the first distance can be the average distance between the first end face and the second edge 70, the minimum distance between the first end face and the second edge 70, or the maximum distance between the first end face and the second edge 70. If the second edge 70 is not perpendicular to the first direction, the first distance can be the average distance between the first edge 60 and the second edge 70, the minimum distance between the first edge 60 and the second edge 70, or the maximum distance between the first edge 60 and the second edge 70.

[0100] If L1 is too large, it is equivalent to the end of the second reinforcing portion 40 away from the protrusion 12 extending to a distant position on the first region 21. This would increase the gap between the positive and negative electrodes when the electrode 100 with the second reinforcing portion 40, which has a concave side and a convex side, is used as the negative electrode 100b and / or the positive electrode 100a to form the electrode assembly 1000, potentially affecting the interface bonding between the positive and negative electrodes. Since the adhesiveness of the active material in the negative electrode 100b is weaker than that in the positive electrode 100a, if L1 is too large, using the electrode 100 with the second reinforcing portion 40 as the negative electrode 100b could easily lead to the active material shedding.

[0101] When 1mm≤L1≤10mm, the extension position of the second reinforcing part 40 on the active material layer 20 is limited, which is beneficial to the interface bonding of the positive and negative electrode sheets and to prevent the active material from falling off.

[0102] In some specific implementations, 2mm ≤ L1 ≤ 6mm. Of course, in other implementations, L1 can be selected as needed, and is not limited here.

[0103] Further reading Figure 3 and Figure 7 Along the first direction, the first edge 60 and the third edge 80 have a second distance L2, where 1mm ≤ L2 ≤ 10mm. This further restricts the extension position of the second reinforcing portion 40 on the active material layer 20, thereby facilitating the interface bonding of the positive and negative electrode sheets and preventing active material loss. It should be noted that the method for obtaining the second distance L2 can refer to the method for obtaining the first distance L1, and will not be repeated here.

[0104] Optionally, continue reading Figure 3 When the second edge 70° is aligned with the third edge 80°, L1 = L2. (Continue reading...) Figure 7 When the second edge 70 and the third edge 80 are not flush, L1 < L2.

[0105] See Figure 8 The first region 21 includes a first sub-region 211 and a second sub-region 212 arranged sequentially along a first direction. The first sub-region 211 is disposed closer to the protrusion 12 than the second sub-region 212. A second reinforcing portion 40 is disposed in the first sub-region 211. Because the second reinforcing portion 40 is disposed in the first sub-region 211, its extension position on the active material layer 20 is indirectly restricted, which facilitates the interface bonding of the positive and negative electrode sheets and prevents the active material from falling off.

[0106] Optionally, continue reading Figure 8 Along the first direction, the first sub-region 211 has a first height M1, and the second sub-region 212 has a second height M2; M2 = (0.1-0.9)M1, or 1mm ≤ M1 ≤ 10mm. This further restricts the extension position of the second reinforcing part 40 on the active material layer 20, so as to further facilitate the interface bonding of the positive and negative electrode sheets and prevent the active material from falling off.

[0107] Specifically, the first sub-region 211 and the second sub-region 212 are divided by the end of the second reinforcing part 40. If the second reinforcing part 40 extends to the edge of the first sub-region 211 (when there are multiple second reinforcing parts 40, at least one second reinforcing part 40 extends to the edge of the first sub-region 211), and the height of the second reinforcing part 40 along the first direction is M4, then M4 = M1. And when the second edge 70 is flush with the third edge 80, M4 = M1 = L1 = L2.

[0108] Continue reading Figure 8 Along the first direction, the first region 21 has a total height M3. A boundary line 50 exists between the first region 21 and the second region 22. Along the first direction, a fifth spacing L3 exists between the first edge 60 and the boundary line 50 (the method for obtaining the fifth spacing L3 can refer to the method for obtaining the first spacing L1). L3 = (0.1-0.9)M3. This ensures that the second reinforcing portion 40 is distributed within a suitable range, defining the extension position of the second reinforcing portion 40 on the active material layer 20, further facilitating the interface bonding of the positive and negative electrode sheets and preventing active material loss. If the end of the second reinforcing portion 40 extends to the edge of the first sub-region 211, L3 = M2.

[0109] The values ​​M1, M2, and M3 mentioned above can be the average height, maximum height, or minimum height of the area; there are no restrictions on these values, and they can be set as needed. Similarly, L3 can be the average spacing, maximum spacing, or minimum spacing; there are also no restrictions on this value.

[0110] In some embodiments, see further reference. Figure 8 Along the thickness direction ( Figure 8 In the Z-direction, the thickness of the first region 21 is less than the thickness of the second region 22. Therefore, the first region 21 can also be defined as the thinned region, and the second region 22 can be positioned as the main region. Generally, along the first direction (… Figure 8 In the Y direction, the thickness of the first region 21 gradually decreases.

[0111] Typically, the active material is a water-based slurry. If the active material is coated with a uniform thickness, due to its fluidity and surface tension, the active material layer 20 will develop protrusions at the edges during drying. These protrusions will be directly subjected to roller pressure during rolling, causing cracks at the edges of the active material layer 20. Therefore, by setting the thickness of the first region 21 to be less than the thickness of the second region 22, a thinned area is formed at the edge of the active material layer 20. Even if protrusions occur in this thinned area during drying, the thinner area will not be subjected to roller pressure during rolling, thus reducing the risk of cracking in the active material layer 20. Meanwhile, since the thinned area has a second reinforcing part 40, which does not extend beyond the thinned area, the actual capacity of the battery will not be lost while increasing the length of the first reinforcing part 30 in the first direction. Furthermore, the second reinforcing part 40 can increase the compaction density of the active material in the thinned area, reduce the risk of material loss, and thus reduce the risk of lithium plating in the thinned area (because the thinned area is thinner, the gap between the positive and negative electrode sheets in this area is larger, and the interlayer gap is prone to poor electrolyte wetting and poor ion transport performance. During high-power charging, lithium plating is likely to occur in the thinned area, i.e., the thinned area is a region prone to lithium plating).

[0112] Furthermore, the average thickness of the first region 21 is less than the average thickness of the second region 22 by a factor of Δt, where 4μm ≤ Δt ≤ 6μm. When Δt is within this range, the difference in average thickness between the first region 21 and the second region 22 is not too small, which can improve lithium plating in the thinned region. At the same time, it also ensures that the difference between the two is not too large, so that even if a protrusion is formed in the thinned region, the protrusion will not be rolled during rolling, thereby reducing the risk of cracking of the active material layer 20.

[0113] In some specific embodiments, △t can be defined as: the difference between the average thickness of the active material in the second region 22 located at the middle position (1 / 2 position) along the first direction and the average thickness of the active material in the first region 21 located 703 mm away from the second edge.

[0114] Optionally, Δt is 5 μm. Of course, in other embodiments, the specific value of Δt is not limited, such as Δt can also be 4 μm, 4.5 μm, 5.5 μm or 6 μm, etc.

[0115] In other embodiments, the thickness of the first region 21 can be set to be equal to the thickness of the second region 22. This ensures that the thickness of the active material layer 20 at each location on the main body 11 is equal, facilitating processing. Simultaneously, with equal thicknesses in the first and second regions 22, the gap between the positive and negative electrodes is not increased, resulting in good electrolyte wetting, good ion transport performance, and reduced likelihood of lithium plating in the first region 21. Furthermore, when the first region 21 is thinned, the resistance to lithium ion migration within the electrode 100 increases, leading to increased battery polarization. This ultimately causes rapid capacity decay, poor cycle performance, and a significant shortening of the battery cell's lifespan. By setting the thickness of the first region 21 to be equal to the thickness of the second region 22, the problems caused by thinner thickness can be mitigated, thus improving the battery cell's lifespan.

[0116] In some embodiments, the thickness of the first region 21 may be slightly greater than the thickness of the second region 22, or the thickness of a portion of the first region 21 may be less than the thickness of the second region 22, while the thickness of the remaining portion of the first region 21 may be greater than or equal to the thickness of the second region 22; this is not limited here. For example, in some specific embodiments, the thickness of a portion of the first region 21 near the protrusion 12 along the first direction may be less than the thickness of the second region 22, while the thickness of the remaining portion of the first region 21 may be greater than or equal to the thickness of the second region 22. In this case, the first region 21 includes not only the thinned region but also a portion of the unthinned region.

[0117] In some embodiments, both sides of the tab 121 have a first reinforcing portion 30 along the thickness direction to further improve the strength of the tab 121. Furthermore, both sides of the first region 21 on the sides of the main body 11 have a second reinforcing portion 40 facing away from the main body 11 along the thickness direction to further improve the strength of the tab 121 and reduce the risk of wrinkling of the electrode sheet 100.

[0118] In other embodiments, along the thickness direction, one side surface of the tab 121 has a first reinforcing portion 30, and the surface of the first region 21 on one side of the main body 11 facing away from the main body 11 has a second reinforcing portion 40.

[0119] In some embodiments, the electrode tab 121 may have a first reinforcing portion 30 on one side surface along the thickness direction, while the first regions 21 on both sides of the main body 11 may have a second reinforcing portion 40 on the surface away from the main body 11. Alternatively, the electrode tab 121 may have a first reinforcing portion 30 on both sides surface along the thickness direction, while the first region 21 on one side of the main body 11 may have a second reinforcing portion 40 on the surface away from the main body. This is not limited here.

[0120] Optionally, see Figure 9Along the thickness direction, the first reinforcing part 30 and the second reinforcing part 40 are both located on the same side surface of the electrode 100, so as to facilitate the simultaneous preparation and formation of the first reinforcing part 30 and the second reinforcing part 40, thereby improving work efficiency.

[0121] In some embodiments, see Figure 10 Along the thickness direction, one surface of the tab 121 is concave, and the other surface is correspondingly convex, forming the first reinforcing part 30. Furthermore, see... Figure 11 and Figure 12 Along the thickness direction, one side of the surface of the first region 21 is concave, and the other side is correspondingly convex, forming the second reinforcing part 40. With this configuration, on the one hand, the first reinforcing part 30 and the second reinforcing part 40 can be formed without reducing the thickness of the tab 121 and the first region 21, which is convenient for forming the first reinforcing part 30 and the second reinforcing part 40 on the thinner electrode sheet 100, reducing the processing difficulty; on the other hand, the first reinforcing part 30 and the second reinforcing part 40 can be made to have a wavy appearance, which can disperse the bending stress concentration point, reduce the accumulation of plastic deformation of the tab 121, and thus reduce the risk of the tab 121 folding.

[0122] In other embodiments, along the thickness direction, one surface of the tab 121 is recessed, while the other surface remains unchanged relative to other areas, forming a first reinforcing portion 30. Essentially, the tab 121 is thinned by compression to form the first reinforcing portion 30. One surface of the first region 21 is recessed, while the other surface remains unchanged relative to other areas, forming a second reinforcing portion 40. Essentially, the first region 21 is thinned by compression to form the second reinforcing portion 40. This arrangement, where one surface is recessed and the corresponding surface is raised to form a reinforcing portion, does not lead to an increase in the overall thickness of the electrode 100.

[0123] Optionally, to form the first reinforcing portion 30 and the second reinforcing portion 40, a pressure roller with a protrusion on its surface is generally used to press the area on the electrode sheet 100 where the reinforcing portion is to be formed, thus forming an indentation or imprint. This indentation or imprint is the corresponding reinforcing portion. By selecting pressure rollers of different shapes, the first reinforcing portion 30 and the second reinforcing portion 40 of different shapes can be formed. The first reinforcing portion 30 and the second reinforcing portion 40 can be formed by the same pressure roller, or they can be formed by different pressure rollers.

[0124] The cross-sectional shapes of the first reinforcing part 30 and the second reinforcing part 40 can be elongated, circular, rhomboid, elliptical, arc-shaped, wavy, or V-shaped, etc. The longitudinal cross-sectional shapes of the first reinforcing part 30 and the second reinforcing part 40 can be rectangular, circular, semi-circular, trapezoidal, etc. When it is necessary to form first reinforcing parts 30 and second reinforcing parts 40 with different cross-sectional and longitudinal cross-sectional shapes, this can be achieved by selecting pressure rollers of different shapes. The cross-sectional and longitudinal cross-sectional shapes of the first reinforcing part 30 and the second reinforcing part 40 can be the same or different, depending on the requirements.

[0125] It should be noted that the first direction and the second direction intersect to form a first plane, the cross-section of which is the surface formed by cutting through the first reinforcing part 30 and the second reinforcing part 40 through the first plane. The second direction intersects with the thickness direction to form a second plane, the longitudinal section of which is the surface formed by cutting through the first reinforcing part 30 and the second reinforcing part 40 through the second plane. Specifically, the first direction, the second direction, and the thickness direction intersect each other. The second direction is... Figure 1 and Figure 2 In the X direction. When the first direction is parallel to the width direction of the current collector 10, the second direction is parallel to the length direction of the current collector 10.

[0126] The first reinforcing part 30 has a first bottom wall and a first side wall that are interconnected, with a smooth transition between the first bottom wall and the first side wall. (Continue reading...) Figure 12 The second reinforcing part 40 has a second bottom wall 41 and a second side wall 42 that are connected to each other. The second bottom wall 41 and the second side wall 42 have a smooth transition. This arrangement can reduce the risk of active material falling out in the area where the second reinforcing part 40 is located. When the longitudinal cross-sectional shape of the second reinforcing part 40 is rectangular or trapezoidal, the corners of the rectangle and trapezoid are rounded.

[0127] It should be noted that when the first reinforcing part 30 and the second reinforcing part 40 are connected to form a reinforcing part, the first bottom wall and the second bottom wall together form the bottom wall of the entire reinforcing part, and the first side wall and the second side wall together form the side wall of the entire reinforcing part, with a smooth transition between the bottom wall and the side wall of the entire reinforcing part.

[0128] Continue reading Figure 9Each electrode tab 121 has a plurality of first reinforcing portions 30, and a first portion corresponding to the electrode tab 121 has a plurality of second reinforcing portions 40. The shapes of the plurality of first reinforcing portions 30 on each electrode tab 121 can be the same or different, and the shapes of the plurality of second reinforcing portions 40 on the first region 21 can be the same or different, and are not limited here. The first reinforcing portions 30 and the second reinforcing portions 40 can be independent of each other or connected as a whole. It should be noted that regardless of whether the groove shapes of the first reinforcing portions 30 and the second reinforcing portions 40 are the same or different, the first reinforcing portions 30 and the second reinforcing portions 40 can be connected as a whole or can be set independently of each other.

[0129] See Figures 13-15 Along the second direction, there is a third spacing D1 between every two adjacent first reinforcing parts 30, and a fourth spacing D2 between every two adjacent second reinforcing parts 40. Where D2 ≥ D1. When D2 is greater than or equal to D1, the distribution density of the second reinforcing parts 40 along the second direction is less than or equal to the distribution density of the first reinforcing parts 30 along the second direction, which can simultaneously improve the folding of the tab 121 and prevent the active material from falling off. It should be understood that in some other embodiments, D2 < D1 may also be set.

[0130] It should be noted that the third spacing refers to the distance between two adjacent first reinforcing parts 30 on the side closest to each other along the second direction. This distance can be the average distance between them, or it can be the maximum or minimum distance between them. The fourth spacing refers to the distance between two adjacent second reinforcing parts 40 on the side closest to each other along the second direction. This distance can be the average distance between them, or it can be the maximum or minimum distance between them.

[0131] Because if D1 and D2 are too large, the effect of improving the folding of tab 121 is limited, while if they are too small, tab 121 is easily torn. Optionally, 1mm≤D1≤10mm and 1mm≤D2≤20mm are chosen so that D1 and D2 are neither too large nor too small, which can balance improving the folding of tab 121 and reducing the tearing of tab 121; at the same time, D2 can be greater than or equal to D1, which can prevent active material from falling out while improving the folding of tab 121.

[0132] Optionally, continue reading Figure 3 , Figure 7 , Figure 9 and Figure 13 The tab 121 is provided with a plurality of first reinforcing parts 30, the cross-section of which is an elongated strip extending along the first direction. (Continue reading) Figure 8 and Figure 9The protrusion 12 has a third height 'a' along the first direction. If 'a' is too large, the tab 121 is at high risk of folding over; if 'a' is too small, it is difficult to connect the electrode terminals. The protrusion 12 has a first width 'b' along the second direction. If 'b' is too large, the tab 121 is prone to cracking during rolling; if 'b' is too small, the welding area is insufficient. The protrusion 12 has a first thickness 'c' along the thickness direction. If 'c' is too large, it wastes space; if 'c' is too small, the tab 121 is not strong enough and is prone to sagging and folding over.

[0133] The aforementioned third height, first width, and first thickness can be average values, maximum values, minimum values, etc., set as needed. In some specific embodiments, the cross-sectional shape of the protrusion 12 is an isosceles trapezoid, with the long side of the isosceles trapezoid connected to the main body 11. The third height is the height of the isosceles trapezoid, the first width is the length of the long side of the isosceles trapezoid, and the thickness of the protrusion 12 is equal at all points, so the first thickness is the thickness at any point on the isosceles trapezoid. It is understood that in other embodiments, the cross-sectional shape of the protrusion 12 is not limited, such as the cross-sectional shape of the protrusion 12 can also be rectangular.

[0134] Continue reading Figure 10 Each first reinforcing part 30 has a first recess depth H1 along the thickness direction. The first recess depth H1 can be the maximum recess depth or the average recess depth, etc.

[0135] H1 / D1 = k*a / (b*c);

[0136] Wherein, 5μm≤H1≤500μm, 1mm≤D1≤10mm, 1*10 -7 ≤k≤0.08.

[0137] Considering that the larger a is, the smaller b is, and the smaller c is, the more likely the tab 121 is to fold over, this application sets H1 / D1 = k*a / (b*c) to limit the third height, first thickness, and first width of the protrusion 12, the first recess depth of the first reinforcing part 30, and the third distance between two adjacent first reinforcing parts 30 within a suitable range, so as to reduce the risk of the tab 121 folding over.

[0138] Optionally, 5mm≤a≤50mm, 10mm≤b≤80mm, and 3μm≤c≤8μm can be set to avoid the third height, first width, and first thickness of the protrusion 12 being too large or too small, thereby reducing the adverse effects caused by being too large or too small.

[0139] Too many layers of tab 121 can easily lead to cold solder joints, while too few layers result in insufficient current carrying capacity. The number of layers of tab 121 (the number of layers of the protrusion 12) should be set in the range of 5-100 layers to reduce the adverse effects of too many or too few layers.

[0140] It is understood that in some other embodiments, the number of layers a, b, c and tab 121 can be selected from other ranges, which are not limited here.

[0141] Because an excessively large H1 can easily tear the tab 121, while an excessively small H1 has limited effect on improving the folding effect of the tab 121. Optionally, H1 can be set to (1-100)c to limit H1 within a suitable range, thereby reducing the folding effect of the tab 121 while avoiding tearing. Specifically, 5μm≤H1≤500μm.

[0142] The sum of the thicknesses of the main body 11 and all the first regions 21 is the second thickness T2. If the first region 21 is provided on one side of the main body 11 along its thickness, the second thickness is the sum of the thickness of the main body 11 and the first region 21 on that side surface. If the first region 21 is provided on both sides of the main body 11 along its thickness direction, the second thickness is the sum of the thickness of the main body 11 and the second regions 22 on both sides. The second reinforcing part 40 has a second recess depth H2. The second thickness can be the maximum thickness, minimum thickness, or average thickness, etc., and the second recess depth can be the maximum recess depth or average recess depth, etc.

[0143] Because an excessively large H2 can easily cause active material to bleed out, while an insufficient depth has limited effectiveness in preventing lithium plating in the thinned area and wrinkling of the electrode 100. Optionally, H2 can be set to (0.05-1)T2 to limit H2 within a suitable range, thereby reducing active material bleeding while also reducing lithium plating in the thinned area and preventing wrinkling of the electrode 100. Specifically, 5μm ≤ H2 ≤ 100μm.

[0144] It should be noted that H1 can be equal to or different from H2. In some specific embodiments, H2 < H1, in order to balance improving the folding of the electrode 100 and preventing the loss of active material.

[0145] In some embodiments, see further reference. Figure 3 , Figure 5 , Figure 7 and Figure 13 Along the first direction, the first reinforcing part 30 and the second reinforcing part 40 are connected to each other to form a reinforcing part. In this way, it is equivalent to the first reinforcing part 30 continuously extending from the tab 121 to the first region 21, so as to improve the reinforcing effect on the tab 121 and reduce the folding of the tab 121.

[0146] Specifically, the cross-sectional shape of the entire reinforcing part is an elongated strip extending along the first direction, so as to increase the length of the reinforcing part along the first direction and improve the reinforcing effect on the tab 121.

[0147] Optionally, continue reading Figure 13The reinforcing part has a first angle θ with the first direction, where 0°≤θ≤20°. Thus, the reinforcing part is parallel to the first direction or has an inclined angle with the first direction to increase the length of the reinforcing part and improve the reinforcing effect.

[0148] In some specific implementations, 0°≤θ≤10°, specifically, θ is 8°. Of course, in other implementations, the specific value of θ is not limited, such as θ can also be 0°, 1°, 2°, 3°, 4°, 5°, 6°, 7°, 9° and 10°, etc.

[0149] Further reading Figure 10 Along the direction opposite to the first direction, the depth of the recess in the reinforcing portion decreases along the thickness direction. Specifically, along the direction opposite to the first direction, the depth of the recess in the reinforcing portion decreases in a gradient or gradually.

[0150] Specifically, along the direction opposite to the first direction, H1 and a satisfy the following relationship:

[0151]

[0152] Where g and h are constants, and 2≤g≤10, 5≤h≤100;

[0153] The second reinforcing part 40 has a second recess depth H2 along the thickness direction.

[0154] H2 and L1 satisfy the following relationship:

[0155]

[0156] Where i and j are constants, 2≤i≤10, 5≤j≤100.

[0157] In some embodiments, see Figure 16 Along the first direction, the first reinforcing part 30 and the second reinforcing part 40 are spaced apart. Specifically, the cross-sectional shape of the first reinforcing part 30 is an elongated strip extending along the first direction (the elongated strip extends along a straight line and is wider along the second direction), and the cross-sectional shape of the second reinforcing part 40 is circular. The circular shape has a smaller pressure-bearing area than the elongated shape, reducing the degree of deformation and damage in the area of ​​the electrode 100 where the second reinforcing part 40 is provided.

[0158] In some embodiments, see further reference. Figure 14 and Figure 15The groove shape of the first reinforcing part 30 is hemispherical, and the first reinforcing part 30 has a first spherical diameter R1. The second reinforcing part 40 has a second spherical diameter R2, where R2 ≤ R1. Specifically, R2 < R1. This makes the area of ​​the second reinforcing part 40 smaller than the area of ​​the first reinforcing part 30, thereby achieving both improved tab folding and prevention of active material spillage. It is understood that in some other embodiments, R2 = R1 may also be set.

[0159] Specifically, 0.5mm≤R1≤5mm; and / or 0.5mm≤R2≤5mm, so that the ball diameters of the first reinforcing part 30 and the second reinforcing part 40 are neither too large nor too small, thereby achieving both improvement of the tab 121 folding and prevention of active material shedding.

[0160] The first reinforcing part 30 has a first opening radius r1, r1≤R1; and / or, the second reinforcing part 40 has a second opening radius r2, r2≤R2. In this case, the grooves of the first reinforcing part 30 and the second reinforcing part 40 can be either complete spheres or incomplete spheres. Since r1≤R1 and / or r2≤R2, the formation of the grooves of the first reinforcing part 30 and the second reinforcing part 40 is facilitated compared to the cases where r1>R1 and / or r2>R2.

[0161] In other embodiments, the groove shape of the first reinforcing part 30 is semi-ellipsoidal, the first long semi-axis of the first reinforcing part 30 ranges from 0.5mm to 20mm, and the first short semi-axis of the first reinforcing part 30 ranges from 0.2mm to 5mm. In this way, it is possible to improve the folding of the tab 121 and prevent the active material from falling out.

[0162] The groove of the second reinforcing part 40 is semi-ellipsoidal. The second long half-axis of the second reinforcing part 40 ranges from 0.5mm to 20mm, and the second short half-axis of the second reinforcing part 40 ranges from 0.2mm to 5mm. In this way, the tab 121 can be improved and active material can be prevented from falling off.

[0163] The semi-ellipsoid can be a complete semi-ellipsoid or an incomplete semi-ellipsoid. That is, the major semi-axis of the groove opening is less than or equal to the major semi-axis of the ellipsoid, and the minor semi-axis of the groove opening is less than or equal to the minor semi-axis of the ellipsoid.

[0164] In some other embodiments, see [reference] Figure 17 The first reinforcing part 30 and / or the second reinforcing part 40 are arc-shaped extending along the first direction, and the central angle of the arc-shaped part ranges from 1° to 180°.

[0165] In some other embodiments, see [reference] Figure 18 and Figure 19The first reinforcing part 30 and / or the second reinforcing part 40 are wavy lines extending along the first direction, with a wavelength range of 1mm-20mm and an amplitude range of 0.1mm-5mm. Wavelength refers to the distance a wave travels in one vibration cycle, and amplitude refers to the distance between the crest and trough of the wave.

[0166] In other embodiments, see Figure 20 The first reinforcing part 30 and the second reinforcing part 40 are connected to form a V-shape, with the opening of the V-shape facing away from the second region 22, and the sharp corner of the V-shape located in the first region 21. When the sharp corner of the V-shape is located in the first region 21, it avoids excessive pressure on the active material area, reducing the degree of deformation and damage to the electrode 100 area corresponding to the second reinforcing part 40. Specifically, the angle of the sharp corner of the V-shape can be 10°-90°, and the sharp corner can be rounded.

[0167] Although the above examples illustrate several shapes of the grooves of the first reinforcing part 30 and the second reinforcing part 40, the shapes of the grooves of the first reinforcing part 30 and the second reinforcing part 40 are not limited to these, and other conceivable shapes may also be used, all of which are included within the protection scope of this application.

[0168] In addition, see Figure 21 This application also provides an electrode assembly 1000. The electrode assembly 1000 is a core component of the battery cell. The electrode assembly 1000 can be formed by winding or stacking a positive electrode 100a, a negative electrode 100b, and a separator 200 that acts as an insulator between the negative electrode 100b and the positive electrode 100a. The electrode tabs 121 of the electrode assembly 1000 are divided into positive tabs 121 and negative tabs 121, which are led out from the positive electrode 100a and the negative electrode 100b, respectively. The positive electrode 100a and / or the negative electrode 100b are the electrode 100 mentioned above.

[0169] In some embodiments, the negative electrode 100b is the electrode 100 described above. In the negative electrode 100b, one side of the surface of the first region 21 is recessed, and the other side is correspondingly protruding, forming a second reinforcing portion 40. This configuration allows the protrusion to fill the gap between the positive and negative electrodes, effectively reducing the interlayer gap between the positive electrode 100a and the negative electrode 100b. This improves electrolyte wetting ability and ion transport performance, reduces the risk of lithium plating, reduces lithium-ion migration resistance, and reduces battery polarization, thereby reducing the risk of excessively rapid battery capacity decay and improving battery cycle performance and cycle life.

[0170] Optionally, both the positive electrode 100a and the negative electrode 100b have thinned regions. The thickness of the first region 21 is less than the thickness of the second region 22, in which case the first region 21 is a thinned region. One side of the thinned region is concave, and the other side is convex, forming a second reinforcing part 40. In this way, the convexity can fill the gap between the thinned regions of the positive and negative electrodes, further reducing the risk of lithium plating.

[0171] Furthermore, the thinned area of ​​the negative electrode 100b has a third thickness t1 along the thickness direction, and the thinned area of ​​the positive electrode 100a has a fourth thickness t2 along the thickness direction; t1≤H2≤(t1+t2). When H2≥t1, the position where the second reinforcing part 40 is provided on the negative electrode 100b protrudes towards the positive electrode 100a to fill the gap between the thinned areas of the positive electrode 100a and the negative electrode 100b, thereby reducing the risk of lithium plating. If H2 is greater than t1+t2, the groove depth of the second reinforcing part 40 is too deep, the active material layer 20 is prone to shedding, and it also causes unevenness at the interface between the positive electrode 100a and the negative electrode 100b, resulting in wavy edges and problems such as wrinkling of the electrode 100. Setting H2≤(t1+t2) can not only reduce the shedding of the active material layer 20, but also prevent wrinkling of the electrode 100.

[0172] Furthermore, H2 / D2 = f*(t1+t2), where f is a constant. This setting ensures that H2, D2, t1, and t2 satisfy a specific functional relationship, thereby reducing the gap between the thinned areas of the positive electrode 100a and the negative electrode 100b, thus reducing the risk of lithium plating. Simultaneously, it keeps the interface between the positive electrode 100a and the negative electrode 100b support flat, reducing material loss from the active material layer 20 and preventing wrinkling of the electrode 100.

[0173] In some specific embodiments, 0.001≤f≤0.9, 5μm≤H2≤100μm, 1mm≤D2≤20mm, 0μm≤t1≤50μm, and 0μm≤t1≤80μm. This ensures that the parameters are within the optimized range, reducing the risk of lithium plating, minimizing material loss from the active material layer 20, and preventing wrinkling of the electrode 100.

[0174] This application also provides a battery cell, which includes a top cover assembly, a housing, and the aforementioned electrode assembly 1000.

[0175] The housing has a hollow structure with internal space for accommodating the electrode assembly 1000, electrolyte, and other components. At least one end of the housing has an opening through which the electrode assembly 1000 can be inserted. A top cover assembly is mounted on the housing and covers its opening, thereby creating a relatively enclosed environment inside the housing to isolate the electrode assembly 1000 from the external environment.

[0176] The aforementioned battery cell can be a lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, and its external outline can be cylindrical, flat, cuboid, or other shapes, but is not limited to these.

[0177] This application also provides a battery, including the aforementioned battery cell. The battery can be a battery pack or a battery module. When the battery is a battery pack, the battery pack specifically includes a battery management system (BMS) and multiple battery cells. Multiple battery cells can be electrically connected in series, parallel, or a combination of series and parallel connections, and communicate with the battery management system, which controls and monitors the operating status of each battery cell. Alternatively, multiple battery cells can first be combined with a module management system to form a battery module, and then the multiple battery modules can be electrically connected in series, parallel, or a combination of series and parallel connections to form a battery pack together with the battery management system.

[0178] Multiple battery cells can be installed on supporting structures such as housings, frames, and brackets. The individual battery cells and the battery management system can be electrically connected through electrical connectors, which can be busbars.

[0179] This application also provides an electrical device, which includes the aforementioned battery cell or battery and is capable of providing electrical energy from the aforementioned battery cell or battery. The aforementioned electrical device can be a vehicle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, power tool, energy storage device, amusement equipment, elevator, and lifting equipment, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, or electric airplane toys, etc.; power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc.; energy storage devices can be energy storage walls, base station energy storage, container energy storage, etc.; amusement equipment can be a carousel, a drop tower, etc.

[0180] The vehicle can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended vehicles, etc. For new energy vehicles, the aforementioned battery can serve as a driving power source, thereby replacing fossil fuels to provide propulsion. This application does not impose any special restrictions on the aforementioned electrical devices.

[0181] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0182] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. An electrode sheet, characterized in that, include: The current collector (10) includes a main body (11) and a protrusion (12) protruding from the main body (11); An active material layer (20) is disposed on at least one side surface of the main body (11) along the thickness direction of the current collector (10); an electrode tab (121) is formed in the area of ​​the protrusion (12) where the active material layer (20) is not disposed; The active material layer (20) has a first region (21) and a second region (22) located on the main body (11). Along a first direction, the first region (21) is closer to the protrusion (12) relative to the second region (22). The first direction is the direction from the main body (11) to the protrusion (12). Along the thickness direction, at least one side surface of the tab (121) has a first reinforcing portion (30), and the active material layer (20) on at least one side surface of the main body (11) has a second reinforcing portion (40), the second reinforcing portion (40) being located on the surface of the first region (21) away from the main body (11).

2. The electrode sheet according to claim 1, characterized in that, Along the thickness direction, the first reinforcing part (30) and the second reinforcing part (40) are both located on the same side surface of the electrode sheet.

3. The electrode sheet according to claim 2, characterized in that, Along the thickness direction, one side surface of the tab (121) is concave and the other side surface is correspondingly convex, forming the first reinforcing part (30); one side surface of the first region (21) is concave and the other side surface is correspondingly convex, forming the second reinforcing part (40).

4. The electrode sheet according to claim 3, characterized in that, Along the first direction, the first reinforcing part (30) and the second reinforcing part (40) are connected to each other to form a reinforcing part.

5. The electrode sheet according to claim 4, characterized in that, The cross-sectional shape of the reinforcing part is an elongated strip extending along the first direction.

6. The electrode sheet according to claim 5, characterized in that, Along a direction opposite to the first direction, the depth of the recess in the reinforcing portion along the thickness direction decreases.

7. The electrode sheet according to claim 5, characterized in that, The reinforcing part has a first included angle θ with the first direction, where 0°≤θ≤20°.

8. The electrode sheet according to claim 3, characterized in that, Along the first direction, the first reinforcing part (30) and the second reinforcing part (40) are spaced apart.

9. The electrode sheet according to claim 8, characterized in that, The first reinforcing part (30) has a cross-sectional shape that is an elongated strip extending along the first direction, and the second reinforcing part (40) has a circular cross-sectional shape.

10. The electrode sheet according to claim 3, characterized in that, The first reinforcing part (30) has a first bottom wall and a first side wall that are connected to each other, and the first bottom wall and the first side wall have a smooth transition; and / or The second reinforcing part (40) has a second bottom wall (41) and a second side wall (42) that are connected to each other, and there is a smooth transition between the second bottom wall (41) and the second side wall (42).

11. The electrode sheet according to claim 3, characterized in that: Along the thickness direction, the protrusion (12) has a first thickness c, the first reinforcing part (30) has a first depth recess H1, the sum of the thicknesses of the main body (11) and all of the first region (21) is a second thickness T2, and the second reinforcing part (40) has a second recess depth H2; wherein, H1 = (1-100)c; And / or, H2 = (0.05-1)T2; And / or, H2 < H1; And / or, 5μm≤H1≤500μm; And / or, 5μm≤H2≤100μm.

12. The electrode sheet according to claim 3, characterized in that: The number of the first reinforcing parts (30) is multiple, and the cross-sectional shape of each first reinforcing part (30) is an elongated strip extending along the first direction. Each pair of adjacent first reinforcing parts (30) has a third spacing D1 along the second direction. The first direction, the thickness direction and the second direction intersect each other. Each of the first reinforcing portions (30) has a first recess depth H1 along the thickness direction, the protrusion (12) has a third height a along the first direction, the protrusion (12) has a first thickness c along the thickness direction, and the protrusion (12) has a first width b along the second direction; H1 / D1 = k*a / (b*c); Wherein, 5μm≤H1≤500μm, 1mm≤D1≤10mm, 1*10 -7 ≤k≤0.

08.

13. The electrode sheet according to any one of claims 1-12, characterized in that, All of the protrusions (12) serve as the tabs (121); or The protrusion (12) includes a connecting part (122) and a tab (121) arranged sequentially along the first direction. The connecting part (122) connects the main body (11) and the tab (121). The active material layer (20) is also disposed on the connecting part (122).

14. The electrode sheet according to claim 13, characterized in that, The second reinforcing part (40) extends to the connecting part (122).

15. The electrode sheet according to any one of claims 1-12, characterized in that, Along the first direction, the second reinforcing portion (40) has a first edge (60) away from the protrusion (12), and the first region (21) has a second edge (70) close to the protrusion (12); Along the first direction, there is a first spacing L1 between the first edge (60) and the second edge (70), where 1mm≤L1≤10mm.

16. The electrode sheet according to claim 15, characterized in that, The main body (11) has a third edge (80) connected to the protrusion (12); Along the first direction, the first edge (60) and the third edge (80) have a second distance L2, 1mm≤L2≤10mm; And / or, L1 = L2.

17. The electrode sheet according to any one of claims 1-12, characterized in that, Along the second direction, there is a third spacing D1 between every two adjacent first reinforcing parts (30), and a fourth spacing D2 between every two adjacent second reinforcing parts (40), wherein the second direction, the thickness direction, and the first direction intersect each other; wherein, D2≥D1; And / or, 1mm≤D1≤10mm; And / or, 1mm≤D2≤20mm.

18. The electrode sheet according to any one of claims 1-12, characterized in that, The thickness of the first region (21) is less than the thickness of the second region (22).

19. An electrode assembly, characterized in that, Including the electrode as described in any one of claims 1-18.

20. A single battery cell, characterized in that, It includes the electrode sheet as described in any one of claims 1-18, or the electrode assembly as described in claim 19.

21. An electrical appliance, characterized in that, Includes the battery cell as described in claim 20.

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