Pole piece, electrochemical device, and electronic device

Abstract

The utility model relates to electrochemical energy storage technical field discloses a kind of pole piece, electrochemical device and electronic equipment, pole piece includes current collector, first protective layer, first insulating layer and first active material layer, current collector has first surface in the side along thickness direction, first surface includes first subface and second subface;First protective layer is connected to first subface;First insulating layer includes main body area and first lap area being connected and being all connected to second subface, and first lap area is located between main body area and first protective layer;The side of main body area opposite to second subface has main body surface, the side of first lap area opposite to second subface has first lap surface, the distance between first lap surface and second subface is less than the distance between main body surface and second subface;First active material layer is connected to the surface of first protective layer, and edge is connected to first lap surface, to be able to improve the compaction density of pole piece in the connecting position of first active material layer and first insulating layer.

Description

Technical Field

[0001] This utility model relates to the field of electrochemical energy storage technology, specifically to an electrode, an electrochemical device, and an electronic device. Background Technology

[0002] Lithium-ion batteries have advantages such as high energy density, long cycle life, and environmental friendliness, and are widely used in various fields. As lithium-ion batteries gradually develop towards fast charging and high energy density, people are paying more and more attention to battery safety. In order to improve the safety performance of the cell, a protective coating is set between the current collector and the active material layer of some electrodes, and a ceramic coating is set at the tail end of the current collector to improve the impact resistance and nail penetration rating of the cell.

[0003] Electrodes employing both protective and ceramic coatings typically exhibit two structural forms: an overlap or a gap between the active material layer and the ceramic coating. For electrode structures with a gap between the active material layer and the ceramic coating, the gap exposes the current collector, posing a higher safety risk. For electrode structures with an overlap between the active material layer and the ceramic coating, the active material layer can shield the current collector between the protective and ceramic coatings, reducing the risk of current collector exposure. However, due to the roller coating process of the active material layer, the overlap area is prone to excessive compaction density, making the electrode susceptible to breakage at the overlap location during cell cycling. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an electrode sheet that can improve the compaction density at the connection position between the first active material layer and the first insulating layer.

[0005] This invention also proposes an electrochemical device and an electronic device having the aforementioned electrodes.

[0006] An electrode sheet according to a first aspect of the present invention includes a current collector, a first protective layer, a first insulating layer, and a first active material layer. The current collector has a first surface on one side along its thickness direction. The first surface includes a first sub-surface and a second sub-surface distributed along the winding direction of the electrode sheet. The first protective layer is connected to the first sub-surface. The first insulating layer includes a main body region and a first overlapping region connected together. Both the main body region and the first overlapping region are connected to the second sub-surface. The first overlapping region is located between the main body region and the first protective layer. The side of the main body region facing away from the second sub-surface has a main surface. The side of the first overlapping region facing away from the second sub-surface has a first overlapping surface. The distance between the first overlapping surface and the second sub-surface is less than the distance between the main surface and the second sub-surface. The first active material layer is connected to the surface of the first protective layer, and its edge is connected to the first overlapping surface.

[0007] The electrode sheet according to the embodiments of this utility model has at least the following beneficial effects: By connecting the first protective layer to the first sub-surface, and by connecting both the main body area and the first overlap area of ​​the first insulating layer to the second sub-surface, and connecting the first active material layer to the surface of the first protective layer with its edge connected to the first overlap surface of the first overlap area, the first active material layer can shield the current collector between the first protective layer and the first insulating layer, reducing the risk of current collector exposure. By setting the distance between the first overlap surface and the second sub-surface to be smaller than the distance between the main body surface of the main body area and the second sub-surface, the thickness of the first overlap area is reduced, and the distance between the first thinned surface and the second sub-surface is reduced. When the first active material layer is roller-coated, the first active material layer can be connected to the first overlap surface, and a space for accommodating the first active material layer is reserved on the first overlap surface, thereby improving the compaction density and thickness at the connection position between the first active material layer and the first overlap area, and reducing the possibility of the electrode sheet breaking at the connection position between the first active material layer and the first overlap area.

[0008] According to some embodiments of the present invention, the first overlapping surface is at least one of a plane, a stepped surface, and an arc surface.

[0009] According to some embodiments of the present invention, the width of the first overlapping area is ≥2 micrometers and ≤20 micrometers; and / or, the minimum thickness of the first overlapping area is ≥2 micrometers and the maximum thickness is ≤30 micrometers.

[0010] According to some embodiments of this utility model, the thickness of the main body region is ≥5 micrometers and ≤50 micrometers.

[0011] According to some embodiments of the present invention, at the connection position between the first active material layer and the first overlapping area, the first active material layer has a second overlapping surface; the second overlapping surface is connected to the first overlapping surface.

[0012] According to some embodiments of the present invention, the sum of the thicknesses of the first active material layer and the first overlapping area at the connection position is less than or equal to the distance between the surface of the first active material layer on the side opposite to the current collector and the first sub-surface.

[0013] According to some embodiments of the present invention, the first insulating layer further includes a second overlapping area, which is connected to the side of the main body region opposite to the first overlapping area; and / or, the first insulating layer further includes a third overlapping area, which is connected to at least one side of the main body region along the width direction of the electrode sheet, and the width direction is perpendicular to the winding direction.

[0014] According to some embodiments of the present invention, the electrode further includes a second protective layer and a second active material layer; the current collector has a second surface on the other side along the thickness direction, the second protective layer is connected to the second surface, and the second active material layer is connected to the surface of the second protective layer; and / or, the first protective layer and the first insulating layer are spaced apart.

[0015] An electrochemical device according to a second aspect of the present invention includes an electrode assembly, which includes a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode. The positive electrode, the separator, and the negative electrode are stacked and wound together. At least one of the positive electrode and the negative electrode is an electrode as described in any of the above embodiments. One end of the positive electrode or the negative electrode having a first insulating layer is located in the outermost layer of the electrode assembly.

[0016] An electronic device according to a third aspect of the present invention includes the electrochemical device described in the above embodiments.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This diagram shows a partial cross-sectional view of the electrode sheet provided in an embodiment of the present invention. Figure 2 It shows Figure 1 Enlarged structural diagram at point II; Figure 3 This diagram shows a partial structural schematic of the electrode sheet provided in the embodiment of the present invention in its unfolded state; Figure 4 A cross-sectional structural diagram of the first insulating layer provided in another embodiment of the present invention is shown; Figure 5 A cross-sectional structural diagram of the first insulating layer provided in another embodiment of the present invention is shown; Figure 6 A cross-sectional structural diagram of the first insulating layer provided in another embodiment of the present invention is shown.

[0019] Figure label: Electrode 100; Current collector 110; First surface 111; First sub-surface 1111; Second sub-surface 1113; Second surface 113; First protective layer 130; First insulating layer 150; Main body area 151; Main body surface 1511; First overlapping area 153; First overlapping surface 1531; Second overlapping area 155; Third overlapping area 157; First active material layer 170; Second overlapping surface 171; Second protective layer 190; Second active material layer 210; Thickness direction Z; Winding direction X; Width direction Y. Detailed Implementation

[0020] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0021] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0022] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0023] In the description of this utility model, unless otherwise explicitly defined, terms such as "setting," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0024] In the description of this utility model, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this utility model. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0025] This application provides an electronic device, which includes an electrochemical device. The electronic device in this application is not particularly limited and can be any electronic device known in the prior art.

[0026] The electronic devices described in this application are not particularly limited in their application and can be used with any electronic device known in the prior art. These electronic devices include, but are not limited to, mobile phones, smartphones, laptops, tablets, wearable devices, smartwatches, smart bracelets, smart glasses, power banks, televisions, game consoles, game controllers, digital cameras, smart speakers, headphones, keyboards, mice, monitors, drones, audio equipment, home appliances, toys, power tools, automobiles, motorcycles, electric bicycles, bicycles, robots, robotic dogs, industrial robots, and android robots.

[0027] In some embodiments, the electrochemical device includes any device in which an electrochemical reaction occurs to interconvert chemical energy and electrical energy, and specific, non-limiting examples include all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0028] In some embodiments, the electrochemical device includes a housing, an electrode assembly, and an electrolyte.

[0029] The housing can be made of steel or a flexible material. The electrode assembly has a wound core structure and is housed within the housing. The electrolyte can fill the housing to wet the electrode assembly.

[0030] The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator located between the positive electrode plate and the negative electrode plate. The positive electrode plate, the separator, and the negative electrode plate are stacked and wound together to form a wound core structure. For details, please refer to the prior art, which will not be elaborated here.

[0031] Please see Figures 1 to 3 In some embodiments, the electrode 100 includes a current collector 110, a first protective layer 130, a first insulating layer 150, and a first active material layer 170.

[0032] In the above embodiments, at least one of the positive electrode and the negative electrode is the electrode 100 of this embodiment.

[0033] The current collector 110 has a first surface 111 on one side along the thickness direction. The first surface 111 includes a first sub-surface 1111 and a second sub-surface 1113 distributed along the winding direction of the electrode 100. The current collector 110 can be a single-layer metal foil or a composite current collector including a first conductive layer, an insulating polymer layer and a second conductive layer stacked sequentially.

[0034] As an example, the first sub-surface 1111 may be located at one end of the current collector 110 in the winding direction of the electrode 100, and the second sub-surface 1113 may be located at the other end of the current collector 110 in the winding direction. The first sub-surface 1111 and the second sub-surface 1113 may be connected or spaced apart.

[0035] The first protective layer 130 is connected to the first sub-surface 1111, and the first insulating layer 150 is connected to the second sub-surface 1113. The first protective layer 130 and the first insulating layer 150 can be used to protect the current collector 110, which can improve the mechanical strength of the electrode 100 and improve the resistance to heavy impact and the needle penetration level of the electrode assembly.

[0036] When the electrode 100 is wound into an electrode assembly, the end of the electrode 100 with the insulating coating can be located in the outermost layer of the electrode assembly. Specifically, the end of the positive or negative electrode with the first insulating layer 150 is located in the outermost layer of the electrode assembly, thereby protecting the internal structure of the electrode assembly. In some other embodiments, the first insulating layer 150 may also be located in the outermost layer on the side facing the interior of the electrode assembly.

[0037] As an example, the first protective layer 130 typically includes boehmite, alumina, conductive agents, and other main components, as detailed in existing technologies. The first insulating layer 150 can be a ceramic coating, typically including boehmite, alumina, adhesives, and other main components, as detailed in existing technologies.

[0038] The first protective layer 130 can be attached to a portion of the first sub-surface 1111 or can completely cover the first sub-surface 1111. The first insulating layer 150 can be attached to a portion of the second sub-surface 1113 or can completely cover the second sub-surface 1113.

[0039] The first insulating layer 150 includes a main body region 151 and a first overlapping region 153. Both the main body region 151 and the first overlapping region 153 are connected to the second sub-surface 1113. The first overlapping region 153 is connected to the main body region 151, and the first overlapping region 153 may be located between the first protective layer 130 and the main body region 151.

[0040] The first overlap area 153 has a first overlap surface 1531 on the side opposite to the second sub-surface 1113. The edge of the first active material layer 170 is connected to the first overlap surface 1531, so that the first active material layer 170 can shield the current collector 110 between the first protective layer 130 and the first insulating layer 150, reducing the risk of exposure of the current collector 110.

[0041] The main body area 151 has a main surface 1511 on the side opposite to the second sub-surface 1113. The distance between the first overlapping surface 1531 and the second sub-surface 1113 is smaller than the distance between the main surface 1511 and the second sub-surface 1113. The first active material layer 170 is connected to the surface of the first protective layer 130. In this way, the thickness of the first overlapping area 153 is reduced, and the distance between the first thinning surface and the second sub-surface 1113 is reduced. When the first active material layer 170 is roller coated, the first active material layer 170 can be connected to the first overlapping surface 1531. The first overlapping surface 1531 has reserved space to accommodate the first active material layer 170, thereby improving the compaction density and thickness at the connection position of the first active material layer 170 and the first overlapping area 153, and reducing the possibility of the electrode 100 breaking at the connection position of the first active material layer 170 and the first insulating layer 150.

[0042] The first overlapping surface 1531 and the main body surface 1511 can be connected. This is possible when the electrode 100 is in an unfolded, flat state (e.g., ...). Figure 3 As shown), the first sub-surface 1111 and the second sub-surface 1113 are generally coplanar, and the main surface 1511 can be parallel or approximately parallel to the second sub-surface 1113.

[0043] The thickness of the first insulating layer 150 at its edge can be reduced by means of laser processing, roll coating, etc., to form a first overlapping area 153 at the edge of the first insulating layer 150. Laser processing is a common method for removing material from the surface of the structure to reduce thickness, and will not be elaborated further. The following explanation will use roll coating to reduce the thickness of the first overlapping area 153 as an example.

[0044] As an example, the first insulating layer 150, the first protective layer 130, and the first active material layer 170 can be coated onto the current collector 110 using different coating rollers. Specific coating methods can be found in existing technologies and will not be elaborated further. For the coating roller used to coat the first insulating layer 150, the outer peripheral wall of the coating roller can be recessed with a first material groove and a second material groove. The first and second material grooves can be distributed along the axial direction of the coating roller and are interconnected. The depth of the first material groove can be less than the depth of the second material groove. When the first insulating layer 150 is coated using the coating roller, the second material groove is deeper, allowing for the coating of a thicker main body area 151 on the second sub-surface 1113; the first material groove is shallower, allowing for the coating of a thinner first overlap area 153 on the second sub-surface 1113.

[0045] In some embodiments, the first protective layer 130 and the first insulating layer 150 may be spaced apart, thereby forming a gap between the first protective layer 130 and the first insulating layer 150. This reduces the situation where the first protective layer 130 and the first insulating layer 150 wet each other during the coating process, resulting in an excessively high density of bonding sites, and also reduces the coating difficulty of the first protective layer 130 and the first insulating layer 150.

[0046] Since the first active material layer 170 is connected to the first overlapping surface 1531, the first active material layer 170 can shield the current collector 110 between the first protective layer 130 and the first insulating layer 150, reducing the exposure of the current collector 110 and helping to avoid damage from burrs, metal particles or external impacts of other structures due to the exposure of the current collector 110.

[0047] As an example, the first surface 111 may also include a third sub-surface, which may be connected between the first sub-surface 1111 and the second sub-surface 1113. It should be noted that, during the coating of the first active material layer 170, due to the influence of the coating process, some of the first active material may enter the gap space and be coated on the third sub-surface.

[0048] In some embodiments, the first lap surface 1531 is planar (e.g., Figure 4 As shown), step surface (as shown) Figure 2 and Figure 5 As shown), curved surface (as shown) Figure 6 At least one of (as shown), thereby allowing for flexible adjustment of the shape of the first overlapping surface 1531.

[0049] The plane can be a plane parallel to the first surface (e.g., Figure 2 As shown), it can also be a plane inclined relative to the first surface (such as...). Figure 4 (As shown).

[0050] As an example, when the first overlapping surface 1531 is inclined relative to the first surface 111, the distance between the first overlapping surface 1531 and the second sub-surface 1113 along the thickness direction can gradually increase along the direction from the first overlapping area 153 toward the main body area 151.

[0051] As another example, when the first overlapping surface 1531 is a stepped surface, the first overlapping surface 1531 may include a first surface and a second surface. The first surface and the main body surface 1511 may have a height difference along the thickness direction of the current collector 110, and the second surface may connect the first surface and the main body surface 1511. The first surface may be parallel to the second sub-surface 1113, or it may be inclined relative to the second sub-surface 1113. The second surface may extend along the thickness direction of the current collector 110, and the extension direction of the second surface may also be inclined relative to the thickness direction of the current collector 110.

[0052] As another example, when the first overlapping surface 1531 is an arc surface, the arc surface can be an arc surface that is concave towards the side facing the current collector 110, or an arc surface that is convex towards the side facing away from the current collector 110, or the arc surface can include a concave arc surface and a convex arc surface (such as a wavy surface).

[0053] Understandably, the first overlapping surface 1531 may also include any two of a plane, a stepped surface, and a curved surface, or the first overlapping surface 1531 may include all three of a plane, a stepped surface, and a curved surface.

[0054] Adjusting the surface shape of a structure using laser processing is a common method and will not be elaborated upon further. The following explanation will use adjusting the shape of the coating roller to adjust the shape of the first overlapping surface 1531 as an example.

[0055] As an example, as described above, the first material trough may have a first opening, a first end wall, and a first peripheral wall, and the second material trough may have a second opening, a second end wall, and a second peripheral wall. Both the first and second openings may be located on the outer peripheral surface of the coating roller and are interconnected. The first opening and the first end wall may be spaced apart and opposite to each other, and the first peripheral wall may extend from the first opening to the first end wall. Similarly, the second opening and the second end wall may be spaced apart and opposite to each other, and the second peripheral wall may extend from the second opening to the second end wall. Understandably, the shape of the first end wall determines the shape of the first overlapping surface 1531, and the shape of the first overlapping surface 1531 can be adjusted by adjusting the shape of the first end wall.

[0056] It should be noted that multiple first material grooves can be provided on the outer peripheral wall of the coating roller. The multiple first material grooves can be respectively located on different sides of the second material groove, so that the different sides of the main body area 151 can be respectively connected to the first overlapping area 153, which will not be described in detail.

[0057] In some embodiments, the width of the first overlap area 153 is ≥2 micrometers and ≤20 micrometers, thereby ensuring that the first overlap area 153 has sufficient width for the first active material layer 170 to overlap, and also preventing the first overlap area 153 from being too wide and affecting the coverage area of ​​the main body area 151.

[0058] The width of the first overlapping area 153 can refer to the width of the first overlapping area 153 in the direction from the first overlapping area 153 to the main body area 151.

[0059] As an example, the width of the first overlap area 153 can be 2 micrometers, 8 micrometers, 10 micrometers, 17.5 micrometers, 20 micrometers, or any other value within any two of the above ranges.

[0060] As an example, the minimum thickness of the first overlap region 153 is ≥2 micrometers and the maximum thickness is ≤30 micrometers, which can improve the situation where the overall thickness of the electrode 100 is affected by the excessive thickness of the first overlap region 153, and ensure the energy density of the electrochemical device.

[0061] As an example, the thickness of the first overlap area 153 can be 2 micrometers, 7 micrometers, 19 micrometers, 22.5 micrometers, 30 micrometers, or any other value within any two of the above ranges.

[0062] The thickness of the first overlapping area 153 can refer to the distance between the first overlapping surface 1531 and the second sub-surface 1113 along the thickness direction.

[0063] In some embodiments, the thickness of the body region 151 is ≥5 micrometers and ≤50 micrometers, which helps the body region 151 to have sufficient thickness to better protect the electrode assembly.

[0064] As an example, the thickness of the main body region 151 can be 5 micrometers, 12 micrometers, 32.5 micrometers, 41 micrometers, 50 micrometers, or any other value within any two of the above ranges.

[0065] In some embodiments, at the connection position between the first active material layer 170 and the first overlapping area 153, the first active material layer 170 may have a second overlapping surface 171.

[0066] The second overlapping surface 171 can be connected to the first overlapping surface 1531, and the shapes of the second overlapping surface 171 and the first overlapping surface 1531 are adapted to each other, so that the second overlapping surface 171 can better fit the contact surface, which helps to make the connection between the first active material layer 170 and the overlapping area tighter.

[0067] In some embodiments, the sum of the thicknesses of the first active material layer 170 and the first overlapping area 153 at the connection position is less than or equal to the distance between the surface of the first active material layer 170 on the side opposite to the current collector 110 and the first sub-surface 1111, thereby avoiding the situation where the connection position protrudes.

[0068] In some embodiments, the first insulating layer 150 may further include a second overlapping area 155.

[0069] The second overlap area 155 is connected to the side of the main body area 151 that is opposite to the first overlap area 153. That is, along the winding direction of the electrode 100, the first overlap area 153, the main body area 151 and the second overlap area 155 are connected in sequence.

[0070] As an example, the main body area 151 is generally rectangular. The first surface 111 may also include a fourth sub-surface, which is connected to the side of the second sub-surface 1113 away from the third sub-surface along the winding direction. That is, the first sub-surface 1111, the third sub-surface, the second sub-surface 1113, and the fourth sub-surface are connected sequentially. The fourth sub-surface can be the end of the first surface 111 at one end in the winding direction. An active layer may be coated on the fourth sub-surface, and the material of the active layer is the same as that of the first active material layer 170. The edge of the active layer may be connected to the second overlap area 155. The connection method and beneficial effects of the active layer and the second overlap area 155 can be referred to the connection method and beneficial effects of the first active material layer 170 and the first overlap area 153, and will not be repeated here.

[0071] The structure of the second overlapping area 155 is roughly the same as that of the first overlapping area 153, and will not be described in detail here. For example, the second overlapping area 155 and the first overlapping area 153 can be arranged symmetrically.

[0072] In some embodiments, the first insulating layer 150 may further include a third overlapping area 157.

[0073] The main body region 151 is connected to at least one side of the electrode 100 along the width direction, and the width direction is perpendicular to the winding direction. Since the third overlap region 157 can be located at the edge of the electrode 100 along the width direction, when the electrode 100 is applied to an electrochemical device, a receiving groove can be formed on the third overlap region 157. The receiving groove can be used to store electrolyte, thereby improving the electrolyte retention capacity.

[0074] In some embodiments, the electrode 100 may further include a second protective layer 190 and a second active material layer 210.

[0075] Among them, the current collector 110 has a second surface 113 on the other side along the thickness direction, that is, the first surface 111 and the second surface 113 are two opposite surfaces of the current collector 110 along the thickness direction.

[0076] The second protective layer 190 can be connected to the second surface 113, and the second active material layer 210 can be connected to the surface of the second protective layer 190. Thus, the second protective layer 190 can also protect the current collector 110, further improving the mechanical strength of the current collector 110. In addition, the current collector 110 has a first active material layer 170 and a second active material layer 210 respectively on both sides in the thickness direction, which can improve the energy density of the electrochemical device.

[0077] Understandably, a second insulating layer may be coated on the second surface 113. The structure, material and function of the second insulating layer can be referred to the first insulating layer 150. The second active material layer 210 can be connected to the second insulating layer. The overlapping method and beneficial effects can be referred to the overlapping method and beneficial effects of the first active material layer 170 and the first overlapping area 153, and will not be repeated here.

[0078] In the electrode 100, electrochemical device, and electronic device provided in this application embodiment, by connecting the first protective layer 130 to the first sub-surface 1111, by connecting the main body region 151 and the first overlap region 153 of the first insulating layer 150 to the second sub-surface 1113, and by connecting the first active material layer 170 to the surface of the first protective layer 130 and its edge to the first overlap surface 1531 of the first overlap region 153, the first active material layer 170 can shield the current collector 110 between the first protective layer 130 and the first insulating layer 150, thereby reducing the risk of exposure of the current collector 110. By setting the distance between the first overlapping surface 1531 and the second sub-surface 1113 to be smaller than the distance between the main surface 1511 and the second sub-surface 1113 of the main body area 151, the thickness of the first overlapping area 153 is reduced, and the distance between the first thinning surface and the second sub-surface 1113 is reduced. When the first active material layer 170 is roller-coated, the first active material layer 170 can be connected to the first overlapping surface 1531. The first overlapping surface 1531 has reserved space to accommodate the first active material layer 170, thereby improving the compaction density and thickness at the connection position between the first active material layer 170 and the first overlapping area 153, and reducing the possibility of the electrode 100 breaking at the connection position between the first active material layer 170 and the first overlapping area 153.

[0079] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An electrode sheet, characterized in that, include: The current collector has a first surface on one side along the thickness direction, the first surface including a first sub-surface and a second sub-surface distributed along the winding direction of the electrode sheet; The first protective layer is connected to the first sub-surface; A first insulating layer includes a connected main body region and a first overlapping region, both of which are connected to a second sub-surface. The first overlapping region is located between the main body region and the first protective layer. The main body region has a main surface on the side facing away from the second sub-surface, and the first overlapping region has a first overlapping surface on the side facing away from the second sub-surface. The distance between the first overlapping surface and the second sub-surface is less than the distance between the main surface and the second sub-surface. The first active material layer is attached to the surface of the first protective layer, and its edge is attached to the first overlapping surface.

2. The electrode sheet according to claim 1, characterized in that, The first overlapping surface is at least one of a plane, a stepped surface, or a curved surface.

3. The electrode sheet according to claim 1, characterized in that, The width of the first overlap area is ≥2 micrometers and ≤20 micrometers; And / or, the minimum thickness of the first overlapping area is ≥2 micrometers and the maximum thickness is ≤30 micrometers.

4. The electrode sheet according to claim 1, characterized in that, The thickness of the main body region is ≥5 micrometers and ≤50 micrometers.

5. The electrode sheet according to claim 1, characterized in that, At the connection point between the first active material layer and the first overlapping area, the first active material layer has a second overlapping surface; The second overlapping surface is connected to the first overlapping surface.

6. The electrode sheet according to claim 5, characterized in that, The sum of the thicknesses of the first active material layer and the first overlapping area at the connection position is less than or equal to the distance between the surface of the first active material layer on the side opposite to the current collector and the first sub-surface.

7. The electrode sheet according to claim 1, characterized in that, The first insulating layer further includes a second overlapping area, which is connected to the side of the main body area opposite to the first overlapping area; And / or, the first insulating layer further includes a third overlap area, wherein the main body region is connected to at least one side of the electrode sheet along the width direction, the width direction being perpendicular to the winding direction.

8. The electrode sheet according to any one of claims 1 to 7, characterized in that, The electrode further includes a second protective layer and a second active material layer; the current collector has a second surface on the other side along the thickness direction, the second protective layer is connected to the second surface, and the second active material layer is connected to the surface of the second protective layer; And / or, the first protective layer and the first insulating layer are spaced apart.

9. An electrochemical device, characterized in that, The electrode assembly includes a positive electrode, a negative electrode, and a separator located between the positive electrode and the negative electrode, wherein the positive electrode, the separator, and the negative electrode are stacked and wound together. At least one of the positive electrode and the negative electrode is an electrode according to any one of claims 1 to 8, wherein the end of the positive electrode or the negative electrode having the first insulating layer is located in the outermost layer of the electrode assembly.

10. An electronic device, characterized in that, Includes the electrochemical device according to claim 9.

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