Electrochemical device and electronic device

Abstract

To provide an electrochemical device capable of improving temperature rise during charging.SOLUTION: An electrochemical device includes an electrode assembly and a conductive plate, where the electrode assembly has a wound structure and includes a first electrode plate. The first electrode sheet includes a first conductive layer and a first layer of conductive material, the first conductive layer including first and second faces. The first conductive material layer is disposed on the first surface including the first region, and the conductive plate is connected to the first region and protrudes from the first electrode plate. The conductive plate includes third and fourth areas connected to each other. The third region includes a connecting region, and the conductive plate is connected to the first region via the connecting region. The third area includes first to fourth sides. The first area includes fifth to seventh sides. A third direction length of the third region is T1, a second direction length of the second region is T2, an area of the third region is S1, an area of the connecting region is S2, a length between the first side and the fifth side is J1, a length between the second side and the sixth side is J2, a length between the third side and the seventh side is J3, and a relationship of S2 / S1 + (+ +) / (+) ≥ 30% is satisfied. J1 T2 J2 T1 J3.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present application relates to the field of energy storage technology, and in particular to electrochemical devices and electronic devices having such electrochemical devices. [Background technology]

[0002] Electrochemical devices (e.g., batteries) are widely used in electronic products such as mobile electronic devices, power tools, and electric vehicles, and users' requirements for the safety performance of electrochemical devices are also increasing.

[0003] When an electrochemical device is charged at a high rate, factors such as its own internal resistance and polarization accumulation due to charging can easily cause the electrochemical device to continuously generate heat and its temperature to rise. This can accelerate the aging of the electrochemical device, leading to a decline in capacity and power performance, as well as volume expansion and deformation, which can affect the product's lifespan. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the shortcomings of the prior art, it is necessary to propose an electrochemical device that can improve the problem of temperature rise during charging. There is also a need to provide an electronic device that includes this electrochemical device. [Means for solving the problem]

[0005] The present application provides an electrochemical device including an electrode assembly and a first conductive plate. The electrode assembly has a wound structure and includes a first electrode sheet. The first electrode sheet includes a first conductive layer and a first conductive material layer. The first conductive layer has opposing first and second surfaces. The first conductive material layer is disposed on the first surface. The first surface has a first area. The first conductive material layer includes a first conductive material area surrounding the first conductive material area to form a first recess.The first area is exposed from the first recess. The first conductive plate is connected to the first area and protrudes from the first electrode sheet. The first conductive plate includes a third area and a fourth area that are connected to each other. A direction perpendicular to the third area is defined as a first direction. In the first direction, the projection of the third area is located within the projection of the first area, and the projection of the fourth area is located outside the projection of the first area. The third area includes a connection area, and the first conductive plate connects to the first area through the connection area. When viewed from the first direction, the third area includes a first side, a second side, a third side, and a fourth side, where the first side and the second side are opposite each other, the third side and the fourth side are opposite each other, and the fourth side connects the fourth area. The first area includes a fifth side, a sixth side, and a seventh side. The extension direction of the third area is defined as a second direction, where the seventh side and the third side are arranged in order in the second direction. In the third direction, the fifth side, the first side, the second side, and the sixth side are provided in this order. The first direction, the second direction, and the third direction are perpendicular to each other. If the size of the third area in the third direction is defined as T1, the size of the third area in the second direction as T2, the area of ​​the projection of the third area in the first direction as S1, the area of ​​the projection of the connection area in the first direction as S2, the distance between the first side and the fifth side as J1, the distance between the second side and the sixth side as J2, and the distance between the third side and the seventh side as J3, then 30%≦ S2 / S1+(J1+J2+J3) / (T1+T2) ≦75% This becomes:

[0006] In the present application, S2 / S1 can reflect the proportion of the overcurrent area of ​​the first conductive plate. When S2 / S1 is large, the overcurrent area of ​​the first conductive plate increases, and the current distribution on the first conductive plate becomes more dispersed and uniform during charging of the electrochemical device. This allows the heat generated on the first conductive plate to be more dispersed during high-current charging, reducing the risk of local overheating of the first conductive plate. In addition, (J1+J2+J3) / (T1+T2) can reflect the proportion of the area available for heat dissipation in the first area. When (J1+J2+J3) / (T1+T2) is large, the heat dissipation area of ​​the first conductive plate increases, reducing the temperature rise during high-current charging. Therefore, the present application defines the sum of S2 / S1 and (J1+J2+J3) / (T1+T2). Range This has improved the safety and reliability of electrochemical devices.

[0007] In some possible embodiments, the first electrode sheet further includes a second conductive material layer disposed on a second surface, the second surface including a second area; The second conductive material layer includes a second conductive material area surrounding the second conductive material area to form a second recess. The second area is exposed in the second recess. In the first direction, the projection of the first area and the projection of the second area at least partially overlap. Therefore, heat generated in the first conductive plate can be dissipated through the first area exposed to the first conductive plate, and can also be conducted to the second area through the overlapping portion between the first and second areas and then dissipated from the second area, thereby further improving heat dissipation efficiency.

[0008] In some possible embodiments, the electrochemical device further includes a first layer including an insulating material and adhering to the third area. In the first direction, a projection of the third area is located within a projection of the first layer. The first layer can reduce the risk of short circuits caused by burrs or solder marks in the connection area penetrating the separator, and can also compensate for a reduction in thickness at the first recess due to the first conductive material layer being provided in that position, thereby making the thickness of the entire electrochemical device more uniform.

[0009] In some possible embodiments, the first layer is also adhered to a first area of ​​conductive material, the projection of the first area being located within the projection of the first layer in the first direction.

[0010] In some possible embodiments, the electrochemical device further includes a second layer including an insulating material. The second layer is also adhered to the second conductive material area. In the first direction, the projection of the second area lies within the projection of the second layer. The second layer is used to compensate for a reduction in thickness at the location caused by providing a second recess in the second conductive material layer.

[0011] In some possible embodiments, the first layer includes an eighth side when viewed in the first direction. In the second direction, the seventh side is located between the eighth side and the third side. If the distance between the edge of the first area and the eighth side in the second direction is defined as L1, and the distance between the seventh side and the eighth side is defined as L3, then L3 / L1≦30%. Therefore, the size of the first conductive material area covered by the first layer is reduced in the second direction, i.e., the active material covered by the first layer that is less likely to exhibit capacitive effect is reduced, and the impact of the first layer on the capacitance of the electrochemical device is reduced.

[0012] In some possible embodiments, a third recess is provided at an edge of the first area in the second direction. The first conductive material area includes a first extension region and a second extension region formed to extend toward the third recess. When viewed from the first direction, the first extension region and the second extension region are provided on both sides of the third recess. Therefore, when the electrode sheet is divided, the thickness of the electrode sheet at the cut edge is uniform, which is advantageous in reducing the risk of wavy edges occurring in the electrode sheet at the cut edge.

[0013] In some possible embodiments, When viewed from the first direction, the first layer includes an eighth side, and in the second direction, the seventh side is provided between the eighth side and the third side; The first extension region and the second extension region are both rectangular, The aforementioned Area 1 The aforementioned 2nd direction Relationship in and The aforementioned The distance between the eighth side is L1. The aforementioned first extension area and The aforementioned The second extension region the dimension in the second direction are the same and all L2, The aforementioned The seventh side and The aforementioned The distance between the eighth side and the do By definition, (L2+L3) / L1≦30%. Therefore, in the second direction, the size of the area of ​​the first conductive material covered by the first layer is reduced, i.e., the active material covered by the first layer that cannot exert a capacitive effect is reduced, and the effect of the first layer on the capacitance of the electrochemical device is reduced.

[0014] In some possible embodiments, if it is defined that the size of the first extending region in the third direction is W1 and the size of the second extending region in the third direction is W2, then (W1 + W2) / T1 ≥ 20%. Thereby, the reduction in the heat dissipation area of the first area due to providing the third recess is improved.

[0015] In some possible embodiments, it is defined that the size of the first extending region in the third direction is W1, the size of the second extending region in the third direction is W2, the distance between the first extending region and the first conductive plate in the third direction is W3, and the distance between the second extending region and the first conductive plate in the third direction is W4.

[0016] In some possible embodiments, W3 < W1.

[0017] In some possible embodiments, W2 < W4.

[0018] In some possible embodiments, W3 < W4.

[0019] In some possible embodiments, in the third direction, the first extending region and the second extending region respectively include a ninth side and a tenth side. The first area is connected by the ninth side and the tenth side. The ninth side and the tenth side are linear or arc-shaped.

[0020] In some possible embodiments, in the second direction, the size of the first extending region and / or the second extending region is L2, the distance between the ninth side and the fourth side is L4, and L2 < L4. Since L4 is relatively large, it is advantageous to further increase the heat dissipation area of the first conductive plate, thereby reducing the temperature rise during high-current charging.

[0021] In some possible embodiments, L1 is in the range of 10 mm to 50 mm. When L1 is large, the size of the first conductive material layer covered with the first layer in the second direction becomes relatively large, thereby increasing the impact on the capacity of the electrochemical device. When L1 is small, the size of the first area in the second direction also becomes small, which in turn reduces the distance J3 between the third side and the seventh side, thereby reducing the heat dissipation capability of the first area.

[0022] In some possible embodiments, the electrochemical device further includes a third layer and a fourth layer, both of which contain an insulating material. In the first direction, the first layer is disposed between the first conductive plate and the third layer, and the second layer is disposed between the first conductive plate and the fourth layer. The third and fourth layers can further compensate for a decrease in the thickness of the electrode sheet in the first recess and the second recess. When the first electrode sheet is a negative electrode sheet and the second electrode sheet is a positive electrode sheet, the third layer can also be used to prevent lithium ions desorbed from the portion of the third conductive material layer corresponding to the third layer in the first direction from migrating to the second recess. Furthermore, by preventing these lithium ions from being embedded in the second recess, the risk of excess lithium ions accumulating and lithium dendrite formation can be reduced. Similarly, the fourth layer can also reduce the risk of lithium dendrite formation.

[0023] In some possible embodiments, the electrode assembly further includes a second electrode sheet, and at least one of the third layer and the fourth layer is bonded to the second electrode sheet, thereby fixing the third layer and the fourth layer in the electrochemical device and serving to compensate for thickness and reduce the risk of lithium dendrite formation.

[0024] In some possible embodiments, an edge of at least one of the first layer or the second layer extends beyond an edge of the first electrode sheet in the second direction.

[0025] In some possible embodiments, the connection area is welded to the first area to provide a high connection strength between the first conductive plate and the first area. The connection area includes a plurality of weld points. The area S2 is the sum of the projected areas of the plurality of weld points in the first direction.

[0026] In some possible embodiments, the electrode assembly further includes a second electrode sheet and a separator, and the first electrode sheet, the separator, and the second electrode sheet are stacked and wound to form the electrode assembly. In the winding direction, the electrode assembly includes a first segment, a first bent segment, a second segment, and a second bent segment, which are connected in this order. The first conductive plate is located on the first segment, which improves flatness when the first conductive plate is connected to the first segment.

[0027] In some possible embodiments, The electrochemical device further includes a housing. The housing includes a main body portion for accommodating the electrode assembly, and a Seal Edge Includes: Seal Edge includes a polymer layer, and the fourth area protrudes from the housing by the polymer layer.

[0028] The present application further provides an electronic device including the electrochemical device. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a schematic diagram illustrating the overall configuration of an electrochemical device according to an embodiment of the present application. [Figure 2] FIG. 2 is a schematic diagram of the electrochemical device shown in FIG. 1 before packaging. [Figure 3A] FIG. 2 is a plan view of an electrode assembly of the electrochemical device shown in FIG. [Figure 3B] 2 is a schematic diagram showing the manufacturing process of the sealing edge of the housing of the electrochemical device shown in FIG. 1. FIG. [Figure 4] FIG. 3B is an enlarged view of part IV of the electrode assembly shown in FIG. 3A. [Figure 5] FIG. 3B is an enlarged view of the electrode assembly shown in FIG. 3A at section V. [Figure 6] 3B is a schematic diagram of the front and back structures of the electrode assembly shown in FIG. 3A after the first electrode sheet has been unfolded. [Figure 7] 3B is a front view of the connection point between the first electrode sheet and the first conductive plate shown in FIG. 3A. FIG. [Figure 8A] 8 is a front view of the first electrode sheet shown in FIG. 7 after the first layer has been removed. [Figure 8B] 8 is a front view of the first electrode sheet shown in FIG. 7 after the first layer has been removed in another embodiment. [Figure 8C] 8C is a schematic projection view of a third area of ​​the first conductive plate shown in FIG. 8B. [Figure 8D] FIG. 8C is a schematic projection diagram of a connection area of ​​the third area shown in FIG. 8B. [Figure 9] FIG. 10 is a front view of a connection point between a first electrode sheet and a first conductive plate in an electrochemical device according to another embodiment of the present disclosure. [Figure 10A] 10 is a front view of the first electrode sheet shown in FIG. 9 after the first layer has been removed. [Figure 10B] 10 is a front view of the first electrode sheet shown in FIG. 9 after the first layer has been removed in another embodiment. [Figure 10C] 10 is a front view of the first electrode sheet shown in FIG. 9 after the first layer has been removed in another embodiment. [Figure 10D] 10 is a front view of the first electrode sheet shown in FIG. 9 after the first layer has been removed in another embodiment. [Figure 10E] 10 is a front view of the first electrode sheet shown in FIG. 9 after the first layer has been removed in another embodiment. [Figure 11] FIG. 10 is a front view of a connection point between a first electrode sheet and a first conductive plate in another embodiment. [Figure 12] 12 is a front view of the first electrode sheet shown in FIG. 11 after the first layer has been removed. FIG. [Figure 13] FIG. 10 is a front view of a connection point between a first electrode sheet and a first conductive plate in an electrochemical device according to still another embodiment of the present application. [Figure 14] 1 is a diagram showing an overall configuration of an electronic device according to an embodiment of the present application; DETAILED DESCRIPTION OF THE INVENTION

[0030] The following clearly and in detail describes the technical aspects of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, and not all of the embodiments. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art of the present application. The terms used in the present specification are only for describing specific embodiments and are not intended to limit the present application.

[0031] The following detailed description of the present application will be given with reference to the preferred embodiments. However, the present application may be embodied in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein. Instead, these exemplary embodiments are provided so that the present application will be fully and completely conveyed to those skilled in the art.

[0032] Additionally, for brevity and clarity, the figures may exaggerate the sizes or thicknesses of various components, layers. Like numbers refer to like elements throughout. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, when element A is referred to as being "connected" to element B, it should be understood that element A may be directly connected to element B, or there may be an intermediate element C, and elements A and B may be indirectly connected to each other.

[0033] Furthermore, when describing embodiments of the present application, the use of "may," "may," and the like means "one or more embodiments of the present application."

[0034] The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the present application. The singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly dictates otherwise. Furthermore, the term "comprising" as used herein refers to the presence of stated features, values, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, values, steps, operations, elements, components, and / or combinations thereof.

[0035] Spatial terms, such as "above," are intended to facilitate the description of the relationship of one element or feature to another element(s) or feature(s) as illustrated in the figures. It should be understood that spatial terms are intended to encompass different orientations of a device or apparatus during use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures were inverted, elements described as "above" or "on" other elements or components would be oriented "below" or "underside" of the other elements or components. Thus, the exemplary term "above" can encompass an orientation of above and below. Terms such as first, second, and third may be used herein to describe various elements, components, regions, layers, and / or portions, but it should be understood that these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another. Thus, a first element, first component, first area, first layer or first portion discussed below may be referred to as a second element, second component, second area, second layer or second portion without departing from the teachings of the exemplary embodiments.

[0036] As shown in FIGS. 1 and 2, one embodiment of the present application provides an electrochemical device 100 including a housing 10, an electrode assembly 20, a first conductive plate 30, and a second conductive plate 40. The electrode assembly 20 is located within the housing 10 and has a wound structure. The first conductive plate 30 and the second conductive plate 40 are both electrically connected to the electrode assembly 20 and protrude from the interior of the housing 10. As shown in FIG. 2, there is only one electrode assembly 20. In other embodiments, there may be multiple electrode assemblies 20. The multiple electrode assemblies 20 are located within the housing 10 and electrically connected in parallel or series. Referring also to FIG. 3A, the electrode assembly 20 includes a first electrode sheet 21, a second electrode sheet 22, and a separator 23 disposed between the first electrode sheet 21 and the second electrode sheet 22. The first electrode sheet 21, the separator 23, and the second electrode sheet 22 are sequentially stacked and wound to form the electrode assembly 20. Here, as shown in Figure 3A, the electrode assembly 20 has a winding central axis C that is perpendicular to the paper surface. The winding direction D is a counterclockwise rotation direction about the winding central axis C shown in Figure 3A. In some embodiments, the winding direction D may be a counterclockwise rotation direction.

[0037] In the present application, a first three-dimensional coordinate system is constructed based on a first direction D1, a second direction D2, and a third direction D3 that are perpendicular to one another. The first direction D1 is a direction perpendicular to the third area 31 of the first conductive plate 30. The second direction D2 is the extension direction of the third area 31 of the first conductive plate 30. A second three-dimensional coordinate system is constructed by defining the first direction D1, the second direction D2, and a fourth direction D4 that are perpendicular to one another when the electrode sheet is unrolled. The fourth direction D4 is the direction from the winding start end to the winding end of the electrode sheet before winding. For example, the fourth direction D4 is the direction from the first winding start end 21a to the first winding end 21b of the first electrode sheet 21 before winding, and the direction from the second winding start end 22a to the second winding end 22b of the second electrode sheet 22 before winding.

[0038] In some embodiments, the electrode assembly 20 includes a first segment 201, a first bent segment 202, a second segment 203, and a second bent segment 204 connected in sequence in the winding direction D. The first direction D1 is the stacking direction of the first electrode sheet 21 in the first segment 201 or the second segment 203. The electrode assembly 20 may have a plurality of first segments 201, a plurality of first bent segments 202, a plurality of second segments 203, and a plurality of second bent segments 204. In some embodiments, the first segment 201 and the second segment 203 may be straight segments. In some other embodiments, the electrode assembly 20 may include four bent segments connected in sequence in the winding direction D.

[0039] Here, the first segment 201 has a first outer surface 201a, and the second segment 203 has a second outer surface 203a. A connection point between the first segment 201 located at the outermost side of the electrode assembly 20 and the first bent segment 202 located at the outermost side of the electrode assembly 20 is a first end 205. The first end 205 is the starting point of the rightmost bent edge of the first bent segment 202 in FIG. 3A in the winding direction D. The first end 205 is also the point where the first outer surface 201a intersects with a dashed line BB formed by extending the innermost and rightmost bent edge of the electrode assembly 20 in the first direction D1. A connection point between the first bent segment 202 located at the outermost side of the electrode assembly 20 and the second segment 203 located at the outermost side of the electrode assembly 20 is a second end 206. The second end 206 is the terminal portion of the rightmost bent edge of the first bent segment 202 in FIG. 3A in the winding direction D. The second end 206 is also the portion where the dashed line BB formed by extending the innermost rightmost bent edge of the electrode assembly 20 in the first direction D1 intersects with the second outer surface 203a. The connection point between the outermost second segment 203 of the electrode assembly 20 and the outermost second bent segment 204 of the electrode assembly 20 is the third end 207. The third end 207 is the starting portion of the leftmost curve of the second bent segment 204 in FIG. 3A in the winding direction D. The third end 207 is also the portion where the dashed line AA formed by extending the innermost leftmost bent edge of the electrode assembly 20 in the first direction D1 intersects with the second outer surface 203a. The connection point between the second bent segment 204 located at the outermost side of the electrode assembly 20 and the first segment 201 located at the outermost side of the electrode assembly 20 is the fourth end 208. The fourth end 208 is the end portion of the leftmost curve of the second bent segment 204 in FIG. 3A in the winding direction D. The fourth end 208 is also the portion where the dashed line AA formed by extending the innermost and leftmost bent edge of the electrode assembly 20 in the first direction D1 intersects with the first outer surface 201a. In the first direction D1, the first end 205 and the second end 206 are aligned, and the third end 207 and the fourth end 208 are aligned.

[0040] 3A, 4, and 5, the first electrode sheet 21 includes a first conductive layer 210, a first conductive material layer 211, and a second conductive material layer 212. The first conductive layer 210 includes a first surface 210a and a second surface 210b that face each other in a first direction D1. The first conductive material layer 211 is provided on the first surface 210a, and the second conductive material layer 212 is provided on the second surface 210b. The second electrode sheet 22 includes a second conductive layer 220, a third conductive material layer 221, and a fourth conductive material layer 222. The second conductive layer 220 includes a third surface 220a and a fourth surface 220b that face each other in the first direction D1. The third conductive material layer 221 is provided on the third surface 220a, and the fourth conductive material layer 222 is provided on the fourth surface 220b. The second conductive material layer 212 and the third conductive material layer 221 face each other in the first direction D1 with the separator 23 interposed therebetween. In some embodiments, as shown in FIG. 3A , after being stacked and wound, the first surface 210a of the first conductive layer 210 faces away from the winding central axis C, and the second surface 210b faces toward the winding central axis C. The third surface 220a of the second conductive layer 220 faces away from the winding central axis C, and the fourth surface 220b faces toward the winding central axis C. In other embodiments, the first surface 210a of the first conductive layer 210 faces toward the winding central axis C, and the second surface 210b faces away from the winding central axis C. In this case, the third surface 220a of the second conductive layer 220 faces toward the winding central axis C, and the fourth surface 220b faces away from the winding central axis C.

[0041] The first electrode sheet 21 may be a positive electrode sheet or a negative electrode sheet. Correspondingly, the first conductive layer 210 may be a positive electrode conductive layer or a negative electrode conductive layer, and both the first conductive material layer 211 and the second conductive material layer 212 may be positive electrode active material layers or negative electrode active material layers. The first conductive layer 210 may have a current collecting function. The second electrode sheet 22 may be a negative electrode sheet or a positive electrode sheet. Correspondingly, the second conductive layer 220 may be a negative electrode conductive layer or a positive electrode conductive layer, and both the third conductive material layer 221 and the fourth conductive material layer 222 may be negative electrode active material layers or positive electrode active material layers. The second conductive layer 220 may also have a current collecting function. In some embodiments, the first electrode sheet 21 is a positive electrode sheet, and the second electrode sheet 22 is a negative electrode sheet. The positive electrode conductive layer may be aluminum foil or nickel foil. The negative electrode conductive layer may be made of at least one of copper foil, nickel foil, and a carbon-based conductive layer.

[0042] The positive electrode active material layer includes a positive electrode active material. The positive electrode active material includes a compound capable of reversibly inserting and extracting lithium ions (i.e., a lithiated intercalation compound). In some embodiments, the positive electrode active material can include a lithium transition metal composite oxide. The lithium transition metal composite oxide includes lithium and at least one element selected from cobalt, manganese, and nickel. In some embodiments, the positive electrode active material is selected from at least one of lithium cobalt oxide (LiCoO2), lithium-nickel-manganese-cobalt ternary material (NCM), lithium manganese oxide (LiMn2O4), lithium nickel-manganese oxide (LiNiO.5Mn1.5O4), or lithium iron phosphate (LiFePO4).

[0043] The negative electrode active material layer includes a negative electrode active material capable of reversibly releasing active ions, as known in the art, but is not limited thereto. Examples include, but are not limited to, one or more combinations of graphite, soft carbon, hard carbon, carbon fiber, mesophase carbon microspheres, silicon-based materials, tin-based materials, lithium titanate, and other metals capable of forming an alloy with lithium. Here, the graphite may be one or more combinations selected from artificial graphite, natural graphite, and modified graphite. The silicon-based material may be one or more combinations selected from pure silicon, silicon-oxygen compounds, silicon-carbon composites, and silicon alloys. The tin-based material may be one or more combinations selected from pure tin, tin-oxygen compounds, tin alloys, and the like.

[0044] The separator 23 includes at least one of polyethylene, polypropylene, polyvinylidene fluoride, polyethylene terephthalate, polyimide, and aramid. For example, the polyethylene may include at least one selected from high-density polyethylene, low-density polyethylene, and ultra-high molecular weight polyethylene. Here, polyethylene and polypropylene play an important role in reducing short circuits and improving battery stability through their shutdown effect.

[0045] As shown in FIGS. 4 and 6 to 8A, the first surface 210a of the first conductive layer 210 includes a first area 2100. The first conductive material layer 211 has a first recess 2110. The first recess 2110 is formed by a first end edge 211a of the first conductive material layer 211 in the direction of the winding central axis C being recessed inward, and does not penetrate a second end edge 211b of the first conductive material layer 211 in the direction of the winding central axis C. The first area 2100 is exposed in the first recess 2110 and is disposed so as to be separated from the first conductive material layer 211. Specifically, the first area 2100 may be exposed by forming a first recess 2110 by etching the first conductive material layer 211 using a laser cleaning method, or by applying a foam gel to the first area 2100 in advance, applying an active material, and then heating the surface to remove the foam gel, or by directly scraping the active material off in the first area 2100 with a doctor blade. However, even after laser cleaning or scraping with a doctor blade, a small amount of active material may remain on the surface of the first area 2100, and this is not a limitation of the present application. When viewed from the first direction D1, the first conductive plate 30 is connected to the first area 2100 and extends from the first area 2100 outward beyond the first edge 211a, allowing connection to an external element (not shown). In order to meet the requirement for high current charging, the first area 2100 may be provided in an area excluding the winding start and winding end of the first electrode sheet 21. In some embodiments, the projections of the first area 2100 and the first recess 2110 in the first direction D1 may both be rectangular. In some specific embodiments, the projections of the first area 2100 and the first recess 2110 in the first direction D1 are both rectangular.

[0046] In some embodiments, the housing 10 may be a packaging bag wrapped with a sealing film such as an aluminum laminate film. That is, the electrochemical device 100 may be a soft-pack battery. Referring to both FIGS. 1 and 2 , the housing 10 includes a main body 11 that houses the electrode assembly 20 and a sealing edge 12 connected to the main body 11. The main body 11 has a first wall 111 and a second wall 112 that face each other in a second direction D2. The sealing edge 12 is connected to the first wall 111 and has a third wall 113 and a second wall 114 that face each other in the second direction D2. In the second direction D2, the third wall 113 is disposed between the first wall 111 and the second wall 112, and the fourth wall 114 is disposed between the first wall 111 and the second wall 112. The first conductive plate 30 and the second conductive plate 40 each extend beyond the sealing edge 12 from the interior of the housing 10 to the exterior of the housing 10. The housing 10 includes a first case 13 and a second case 14 arranged opposite each other, and is formed by heat-sealing the first case 13, which has a first space 130, to the flat second case 14. After the first case 13 and the second case 14 are heat-sealed, the first space 130 is sealed by the second case 14 to form an accommodating space for accommodating the electrode assembly 20. Of course, the first case 14 may have a second space (not shown). After the first case 13 and the second case 14 are heat-sealed, the first space 130 and the second space are combined with each other to form an accommodating space for accommodating the electrode assembly 20.

[0047] As shown in FIG. 3B , the first case 13 and the second case 14 can be obtained by folding a single sealing film. That is, the first case 13 and the second case 14 are each multilayer sheets formed by sequentially stacking a protective layer 131, a metal layer 132, and a sealing layer 133. The protective layer 131 may be made of a polymer material that protects the metal layer 132, reduces the risk of damage to the metal layer 132 due to external forces, and slows the penetration of air from the external environment, thereby maintaining a normal operating environment within the electrochemical device 100. The polymer material of the protective layer 131 may be at least one selected from polyethylene terephthalate, polybutylene terephthalate, polyvinylidene fluoride, polytetrafluoroethylene, polypropylene, polyamide, and polyimide. The metal layer 132 may be used to slow the penetration of moisture from the external environment and reduce damage to the electrode assembly 20 due to external forces. In some embodiments, the metal layer 132 may be an aluminum foil layer or a steel foil layer. The sealing layer 133 is used for sealing and can reduce the risk of the multilayer sheet being dissolved or swollen by an organic solvent in the electrolyte solution. The sealing layer 133 also reduces the risk of corrosion of the metal layer 132 due to contact with the electrolyte in the electrolyte solution. The sealing layer 133 includes a polymer material that melts when heated. The polymer material may be at least one selected from polypropylene, propylene copolymer, polyethylene, and polymethyl methacrylate. When fabricating the housing 10, a sealing cap is used to simultaneously apply a certain temperature and pressure to the edges of the first case 13 and the second case 14, melting and bonding the sealing layer 133 of the first case 13 and the sealing layer 133 of the second case 14 to each other, thereby forming the polymer layer 134. Therefore, after the edge seal 12 is formed by heat sealing, the edge seal 12 includes the protective layer 131, the metal layer 132, the polymer layer 134, the metal layer 132, and the protective layer 131, which are sequentially stacked.

[0048] In some other embodiments, the electrochemical device 100 is not limited to a soft-pack battery, but may be a steel shell battery or an aluminum shell battery, etc., and the present application is not limited thereto.

[0049] The electrochemical device 200 includes an electrode assembly 20 and a first conductive plate 30. The electrode assembly 20 includes a first electrode sheet 21. The first electrode sheet 21 includes a first conductive layer 210 and a first conductive material layer 211.

[0050] Here, the first conductive layer 210 includes a first surface 210a and a second surface 210b facing in the opposite direction to the first surface 210a. When viewed in a first direction D1 perpendicular to the first surface 210a, the first conductive layer 210 further includes a first end side 211b in a second direction D2 perpendicular to the first direction D1, and a second end side 211a located on the opposite side to the first end side 211b in the second direction D2 and including a third recess R when viewed in the second direction D2.

[0051] The first conductive material layer 211 is provided on the first surface 210a of the first conductive layer 210, is spaced apart from at least a part of the fourth recess 4, and is provided from the second end side 211a to the first end side 211b.

[0052] The first conductive plate 30 is provided on the first surface 210a of the first conductive layer 210, is spaced apart from the first conductive material layer 211, and overlaps with the third recess R when viewed along the first direction D1.

[0053] In the electrochemical device described above, the first conductive material layer 211 includes a portion that connects to the second end side 211a and the edge of the third recess R when viewed along the first direction D1.

[0054] In the above-mentioned electrochemical device, when viewed along the first direction D1, in a third direction D3 perpendicular to the second direction D2, the first conductive material layer 211 includes a first side edge R1 that contacts the second end edge 211a and faces the first conductive plate 30.

[0055] In the above-described electrochemical device, when viewed along the first direction D1, in the third direction D3, the first conductive material layer 211 includes a fifth edge 2101 that is spaced apart from the first side edge R1 and faces the first conductive plate 30.

[0056] In the electrochemical device described above, the first conductive material layer 211 includes a ninth side 2114 that contacts the first side R1 and the fifth side 2101.

[0057] In the electrochemical device described above, the distance W3 from the first conductive plate 30 to the first side edge R1 in the third direction D3 is shorter than the distance W1 from the first side edge R1 to the fifth side 2101 in the third direction D3.

[0058] In the electrochemical device described above, when viewed along the first direction D1, the first conductive material layer 211 includes a portion that contacts the second end edge 211a and the third recess R. Furthermore, when viewed along the first direction D1, the first conductive material layer 211 further includes, in a third direction D3 that is orthogonal to the second direction D2, a second side edge R2 that contacts the second end edge 211a and faces the first conductive plate 30, and a sixth side 2102 that is spaced apart from the second side edge R2 and faces the first conductive plate 30.

[0059] In the electrochemical device described above, the first conductive material layer 211 includes a tenth side 2115 that contacts the second side R2 and the sixth side 2102.

[0060] In the electrochemical device described above, the distance W4 from the first conductive plate 30 to the second side edge R2 in the third direction D3 is longer than the distance W2 from the second side edge R2 to the tenth side 2115.

[0061] In the electrochemical device described above, the distance W3 from the first conductive plate 30 to the first side edge R1 in the third direction D3 is shorter than the distance W4 from the first conductive plate 30 to the second side edge R2.

[0062] In the electrochemical device described above, the distance L2 from the second end side 211a to the ninth side 2114 in the second direction D2 is shorter than the distance L4 from the ninth side 2114 to the bottom side R3 of the third recess R in the second direction D2.

[0063] In the electrochemical device described above, the third recess R has a sloped edge R extending from the second end edge 211a to the bottom edge R3 of the third recess. 11 Includes:

[0064] In the electrochemical device described above, the electrode assembly 20 includes a first layer 50 that covers at least a portion of the first conductive plate 30 and the first side edge R1 and that has an insulating material.

[0065] As shown in FIGS. 7 and 8A , the first conductive plate 30 includes a third area 31 and a fourth area 32 connected to the third area 31. In the first direction D1, the projection of the third area 31 is located within the projection of the first area 2100. That is, the projection of the third area 31 overlaps at least a portion of the projection of the first area 2100, and the projection of the fourth area 32 is located outside the projection of the first area 2100. As shown in FIG. 1 , the fourth area 32 protrudes from the housing 10. Referring to FIGS. 1 and 3B , when the electrochemical device 100 is a soft-pack battery, the fourth area 32 protrudes from the housing 10 through the polymer layer 134 in the sealing edge 12. In some embodiments, the plane on which the sealing edge 12 is located is perpendicular to the plane on which the first wall 111 is located. In this case, the second direction D2 may be defined as not only the extension direction of the third area 31 but also the extension direction of the entire first conductive plate 30. However, in another embodiment, the size of the electrochemical device 100 in the second direction D2 can be reduced by folding the sealing edge 12 back to the first wall 111, thereby increasing the space utilization rate and the energy density. In this case, the second direction D2 is the extension direction of the third area 31, but the extension direction of the fourth area 32 located within the sealing edge 12 is perpendicular to the second direction D2.

[0066] The third area 31 includes a connection area 311 and an edge region 312 surrounding the connection area 311. The first conductive plate 30 is connected to the first area 2100 by the connection area 311. That is, the connection area 311 is a location where current flows when the electrochemical device 100 is charged. In some embodiments, the first conductive plate 30 is soldered to the first area 2100 via the connection area 311, thereby providing a relatively strong connection between the first conductive plate 30 and the first area 2100. Here, when the connection area 311 and the first area 2100 are welded, a plurality of weld points 3110 are formed, and the connection area 311 and the first area 2100 are fixed by the weld points 3110. A larger number of weld points 3110 can reduce the contact resistance between the first conductive plate 30 and the first electrode sheet 21, thereby reducing the amount of heat generated when the electrochemical device 100 is charged. In another embodiment, the first conductive plate 30 may be connected to the first area 2100 by conductive paste or other methods.

[0067] 7 and 8A, the plurality of welding points 3110 may be arranged in a single matrix when viewed from the first direction D1. In this case, the edge region 312 is the region other than the welding points 3110 located on the outermost periphery in the third area 31. In other embodiments, as shown in FIG. 8B, the plurality of welding points 3110 may be arranged in a matrix such that the connection area 311 includes a plurality of spaced apart regions. In this case, the edge region 312 also includes the region located between adjacent rows and columns in the third area 31.

[0068] As shown in FIGS. 7 and 8A, the third area 31 may be substantially rectangular when viewed in the first direction D1. The third area 31 includes a first side 3101, a second side 3102, a third side 3103, and a fourth side 3104. The first side 3101 and the second side 3102 face each other in the third direction D3. The third side 3103 and the fourth side 3104 face each other in the second direction D2. The third side 3103 connects both ends of the first side 3101 and the second side 3102. The fourth side 3104 connects both ends of the first side 3101 and the second side 3102. The fourth side 3104 is a boundary line between the third area 31 and the fourth area 32. In some embodiments, the first side 3101 and the second side 3102 each extend along the second direction D2, and the third side 3103 and the fourth side 3104 each extend along the third direction D3.

[0069] The first area 2100 includes a fifth side 2101, a sixth side 2102, and a seventh side 2103. The fifth side 2101 and the sixth side 2102 face each other in the third direction D3. The seventh side 2103 connects the ends of the fifth side 2101 and the sixth side 2102. When viewed from the first direction D1, the seventh side 2103 faces the third end side 2104 of the first area 2100 in the second direction D2. It is understood that the first recess 2110 has a three-dimensional structure, and when viewed from the first direction D1, the first recess 2110 includes multiple sides (not shown) that are connected in sequence. When viewed from the first direction D1, the fifth side 2101, the sixth side 2102, and the seventh side 2103 of the first area 2100 each overlap the sides of the first recess 2110. In some embodiments, the fifth side 2101 and the sixth side 2102 each extend along the second direction D2, and the seventh side 2103 extends along the third direction D3. In the second direction D2, the seventh side 2103 and the third side 3103 are arranged in this order, and the seventh side 2103 and the third side 3103 at least partially oppose each other. In some embodiments, the seventh side 2103 and the third side 3103 may be parallel to each other. In the third direction D3, the fifth side 2101, the first side 3101, the second side 3102, and the sixth side 2102 are arranged in this order, and the fifth side 2101 and the first side 3101 at least partially oppose each other, and the second side 3102 and the sixth side 2102 at least partially oppose each other. In some embodiments, the fifth side 2101, the first side 3101, the second side 3102, and the sixth side 2102 may be parallel to each other.

[0070] Here, the seventh side 2103 and the third side 3103 being arranged in sequence in the second direction D2 means that an imaginary line extending along the second direction D2 passes through the seventh side 2103 and the third side 3103 in succession. The fifth side 2101, the first side 3101, the second side 3102, and the sixth side 2102 being arranged in succession in the third direction D3 means that an imaginary line extending along the third direction D3 passes through the fifth side 2101, the first side 3101, the second side 3102, and the sixth side 2102 in succession. In some embodiments, the second direction D2 is the direction of the winding central axis C, and the third direction D3 is perpendicular to the second direction D2.

[0071] 7 and 8A, the fifth side 2101, the sixth side 2102, and the seventh side 2103 are all linear. In other embodiments, when the first area 2100 is formed by laser cleaning or the like, at least one of the fifth side 2101, the sixth side 2102, and the seventh side 2103 may have an uneven shape, and this is not a limitation of the present application.

[0072] As shown in FIGS. 7 and 8A, the first conductive plate 30 is provided at approximately the middle of the first area 2100 in the third direction D3.

[0073] If the dimension of the third area 31 in the third direction D3 is T1, the dimension of the third area 31 in the second direction D2 is T2, the area of ​​the projection of the third area 31 in the first direction D1 is S1 (shown in Figure 8C), the area of ​​the projection of the connection area 311 in the first direction D1 is S2 (shown in Figure 8D), the distance between the first side 3101 and the fifth side 2101 is J1, the distance between the second side 3102 and the sixth side 2102 is J2, and the distance between the third side 3103 and the seventh side 2103 is J3, then the heat dissipation coefficient K of the first area 2100 is K = S2 / S1 + (J1 + J2 + J3) / (T1 + T2) ≧ 30%.

[0074] Here, S2 / S1 may reflect the area ratio of the connection area 311 to the third area 31, i.e., the overcurrent area ratio of the first conductive plate 30. When S2 / S1 is large, the overcurrent area of ​​the first conductive plate 30 becomes larger, and the current distribution on the first conductive plate 30 becomes more dispersed and uniform during charging of the electrochemical device 100. Therefore, the heat generated on the first conductive plate 30 during high-current charging is more dispersed, and the risk of local overheating of the first conductive plate 30 is reduced. Note that J1 reflects the length of first area 2100 protruding from one side of first side 3101 of first conductive plate 30, J2 reflects the length of first area 2100 protruding from one side of second side 3102 of first conductive plate 30, and J3 reflects the length of first area 2100 protruding from one side of third side 3103 of first conductive plate 30, so (J1+J2+J3) / (T1+T2) can reflect the occupancy rate of the area of ​​first area 2100 exposed to first conductive plate 30, i.e., the proportion of the area available for heat dissipation from first area 2100. When (J1+J2+J3) / (T1+T2) is large, the heat dissipation area of ​​first conductive plate 30 increases, reducing temperature rise during large current charging. Therefore, the present application defines the heat dissipation coefficient K of the first area 2100 as the sum of S2 / S1 and (J1+J2+J3) / (T1+T2), and improves the safety and reliability of the electrochemical device 100 by setting the heat dissipation coefficient K≧30%.

[0075] Here, J1, J2, J3, T1, and T2 are each obtained by a direct measurement method. The measurement step includes disassembling the electrochemical device 100, using the first electrode sheet 21 as a measurement sample, and directly measuring the values ​​of J1, J2, J3, T1, and T2 with a camera or other appropriate gauge, or taking an image of the first electrode sheet 21 and measuring them in the image.

[0076] S1 can be calculated from T1 and T2 in conjunction with the specific shape of the third area 31. If the third area 31 is rectangular, S1 is the product of T1 and T2.

[0077] In some embodiments, when the connection area 311 is welded to the first area 2100, S2 is the sum of the areas of the projections of the multiple welding points 3110 in the first direction D1. As shown in FIG. 8D, when the number of welding points 3110 is n (n is a natural number greater than 1), and the areas of the projections of the n welding points 3110 in the first direction D1 are each S 21 , S 22 ,...S 2n Then, S2=S 21 +S 22 +...+S 2n Here, S2 can be measured using an imaging method. The measurement step involves disassembling the electrochemical device 100, taking the first electrode sheet 21 as a measurement sample, capturing a first image including the connection area 311 from a first direction D1, obtaining an image of a reference object with a known area S0 as a second image, calculating the number n1 of pixels corresponding to the welding point 3110 in the first image, and calculating the number n0 of pixels corresponding to the reference object in the second image. The area S2 of the welding point 3110 is calculated based on the area A0, the number n1, and the number n0, i.e., S2 = (S0 × n0) / n1. The measurement of S2 is not limited to the above method. In other embodiments, if the connection area 311 is connected to the first area 2100 in a different manner, S1 can be calculated from the size of each dimension of the connection area 311 or the specific shape of the connection area 311.

[0078] As shown in FIG. 4 , in some embodiments, the second surface 210b of the first conductive layer 210 is defined to include a second area 2105. The second conductive material layer 212 includes a second recess 2120. The second area 2105 is exposed in the second recess 2120 and is spaced apart from the second conductive material layer 212. However, a small amount of active material may remain on the surface of the second area 2105; this is not a limitation of the present application. In the first direction D1, the projection of the first area 2100 and the projection of the second area 2105 at least partially overlap. This allows heat generated in the first conductive plate 30 to be dissipated not only through the first area 2100 exposed to the first conductive plate 30 but also through the overlap between the first area 2100 and the second area 2105 to be dissipated by the second area 2105. This further improves heat dissipation efficiency. In some specific embodiments, in order to further improve heat dissipation efficiency, the projection of the first area 2100 and the projection of the second area 2105 may be arranged to completely overlap in the first direction D1.

[0079] When the first conductive plate 30 is soldered to the first area 2100 via the connection area 311, burrs or solder marks may be formed on the connection area 311. These burrs or solder marks may pierce the separator 23, causing a short circuit. As shown in FIGS. 4, 6, and 7, in some embodiments, the electrochemical device 100 further includes a first layer 50 to which at least the third area 31 is attached, the first layer 50 including an insulating material. In the first direction D1, the projection of the first area 210 is located within the projection of the first layer 50. That is, the first layer 50 completely covers at least the third area 31. Furthermore, the first layer 50 may completely cover at least the first area 2100. The first layer 50 can reduce the risk of burrs or solder marks on the connection area 311 piercing the separator 23, causing a short circuit. Furthermore, by providing a first recess 2110 in the first conductive material layer 211, the first layer 50 can compensate for a reduction in thickness at that location, thereby making the overall thickness of the electrochemical device 100 more uniform. Here, the first layer 50 may be single-sided or double-sided rubber, and its specific material may be at least one selected from polypropylene, polyethylene, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, polymethyl methacrylate, and polyethylene glycol. In another embodiment, the first layer 50 may be a ceramic coating layer.

[0080] In some embodiments, the first layer 50 may extend beyond the first area 2100 and cover and adhere to a portion of the first conductive material layer 211. Specifically, the first conductive material layer 211 includes a first conductive material area 2111 formed around the first recess 2110. The first conductive material area 2111 is also adhered to the first layer 50. For ease of distinction, FIGS. 7 and 8A show the first conductive material area 2111 and other regions of the first conductive material layer 211 with different filling methods. However, this does not mean that the first conductive material area 2111 and other regions of the first conductive material layer 211 are fabricated using different active materials, and there is no clear limit between them.

[0081] As shown in FIG. 7 , when viewed from the first direction D1, the first layer 50 includes an eighth side 51. In the second direction D2, the seventh side 2103 is located between the eighth side 51 and the third side 3103. If the distance between the third end side 2104, which faces the seventh side 2103, and the eighth side 51 in the second direction D2 of the first area 2100 is defined as L1, and the distance between the seventh side 2103 and the eighth side 51 is defined as L3, then L3 / L1≦30%. It can be understood that covering the first conductive material area 2111 with the first layer 50 reduces the material in the first conductive material area 2111 from exhibiting capacitive effects during charge and discharge. By designing the first conductive material area 2111 to satisfy L3 / L1, the size of the first conductive material area 2111 covered by the first layer 50 in the second direction D2 is reduced, i.e., the active material covered by the first layer 50 from exhibiting capacitive effects is reduced. This reduces the effect of the first layer 50 on the capacity of the electrochemical device 100 .

[0082] In some embodiments, L1 is in the range of 10 to 50 mm. When L1 is large, the size of the first conductive material layer 211 covered by the first layer 50 in the second direction D2 becomes relatively large. This increases the impact on the capacity of the electrochemical device 100. When L1 is small, the size of the first area 2100 in the second direction D2 also becomes small. Therefore, the distance J3 between the third side 3103 and the seventh side 2103 is also small, so the heat dissipation coefficient K of the first area 2100 decreases, and the heat dissipation capacity decreases relatively.

[0083] As shown in FIGS. 6 and 7, in some embodiments, the edge 52 of the first layer 50 may extend beyond the edge of the first electrode sheet 21 in the second direction D2.

[0084] As shown in FIG. 4 , in some embodiments, the second conductive material layer 212 includes a second conductive material area 2121 formed to surround the second recess 2120. The electrochemical device 100 further includes a second layer 60 containing an insulating material. The second layer 60 covers the second area 2105 and is bonded to the second conductive material area 2121. That is, the projection of the second area 2105 is located within the projection of the second layer 60 in the first direction D1. The second layer 60 can be used to compensate for the thickness reduction at this location by providing the second recess 2120 in the second conductive material layer 212. In some embodiments, the second layer 60 can be a single-sided rubber, double-sided rubber, or ceramic coated layer.

[0085] As shown in FIG. 6, in some embodiments, the edge 61 of the second layer 60 may extend beyond the edge of the first electrode sheet 21 in the second direction D2.

[0086] As shown in FIG. 4 , in some embodiments, the electrochemical device 100 may include a third layer 70 and a fourth layer 80. Both the third layer 70 and the fourth layer 80 include an insulating material. In the first direction D1, the first layer 50 is disposed between the first conductive plate 30 and the third layer 70, and the second layer 60 is disposed between the first conductive plate 30 and the fourth layer 80. The third layer 70 and the fourth layer 80 can further compensate for the reduction in thickness of the electrode sheet in the first recess 2110 and the second recess 2120. Furthermore, after burrs or solder marks in the connection area 311 pierce the separator 23, the third layer 70 can cover the burrs or solder marks in this area, further reducing the risk of short circuits. When the first electrode sheet 21 is a positive electrode sheet and the second electrode sheet 22 is a negative electrode sheet, the projection of the third layer 70 is located within the projection of the first layer 50 in the first direction D1 (i.e., the end of the third layer 70 does not extend beyond the end of the first layer 50 in the first direction D1). This allows lithium ions desorbed from the portion of the first conductive material layer 211 located around the first layer 50 in the first direction D1 to be sufficiently accepted by the third conductive material layer 221, reducing the risk of excess lithium ions accumulating and causing lithium dendrites, thereby improving safety. Similarly, the projection of the fourth layer 80 is located within the projection of the second layer 60 in the first direction D1 (i.e., the end of the third layer 70 does not extend beyond the end of the first layer 50 in the first direction D1). This allows lithium ions desorbed from the portion of the second conductive material layer 212 located around the second layer 60 in the first direction D1 to be sufficiently accepted by the fourth conductive material layer 222, reducing the risk of excess lithium ions accumulating and causing lithium dendrites, thereby improving safety. In some embodiments, the third layer 70 and the fourth layer 80 may each be a single-sided rubber, double-sided rubber, or ceramic coated.

[0087] In another embodiment, when the first electrode sheet 21 is a negative electrode sheet and the second electrode sheet 22 is a positive electrode sheet, the third layer 70 may be used to prevent lithium ions desorbed from a portion of the third conductive material layer 221 corresponding to the third layer 70 in the first direction D1 from migrating to the second recesses 2120. This reduces the risk of excess lithium ions being stored and lithium dendrites being formed due to the second recesses 2120 being unable to embed all of the lithium ions. Similarly, the fourth layer 80 can be used to prevent lithium ions desorbed from a portion of the fourth conductive material layer 222 corresponding to the fourth layer 80 from migrating to the first recesses 2110 in the first direction D1, reducing the risk of excess lithium ions being stored and lithium dendrites being formed due to the first recesses 2110 being unable to embed all of the lithium ions.

[0088] 4 , in some specific embodiments, the third layer 70 is adhered to the third conductive material layer 221 of the second electrode sheet 22, and the fourth layer 80 is adhered to the fourth conductive material layer 222 of the second electrode sheet 22. This serves to fix the third layer 70 and the fourth layer 80 within the electrochemical device 100, compensate for thickness, and reduce the risk of lithium dendrite formation. Of course, in other embodiments, the separator 23 may be adhered to the third layer 70 and the fourth layer 80.

[0089] 5, in some embodiments, the second electrode sheet 22 may adopt a design similar to that of the first electrode sheet 21. That is, a second conductive plate 40 is connected to the empty area of ​​the second electrode sheet 22, and the heat dissipation coefficient of the empty area is set to be 30% or more. This further improves the safety and reliability of the electrochemical device 100.

[0090] As shown in Figures 3A to 5, in some embodiments, when the first segment 201 and the second segment 203 are straight segments, both the first conductive plate 30 and the second conductive plate 40 are located on the first segment 201, thereby improving flatness when the first conductive plate 30 is connected to the first area 2100.

[0091] As shown in FIGS. 9 and 10A , another embodiment of the present disclosure further provides an electrochemical device 200. The electrochemical device 200 differs from the electrochemical device 100 in at least the following respects. A third recess R is provided inward at a third end edge 2104 of the first area 2100 in the second direction D2 (i.e., the edge opposite the seventh edge 2103 of the first area 2100). The third recess R includes a first side edge R1, a second side edge R2, and a bottom edge R3. The first side edge R1 and the second side edge R2 face each other in the third direction D3. When viewed from the first direction D1, the first side edge R1 and the second side edge R2 are both connected to the first end edge 211a of the first conductive material layer 211. Both ends of the bottom edge R3 are connected to the first side edge R1 and the second side edge R2, respectively. When viewed from the first direction D1, the first side R1 is a slope edge R 11 and has a slope edge R 11 The second side R2 is connected to the bottom side R3. The second side R2 is connected to the slope edge R 21 The slope edge R 21 is connected to the base R3. When viewed along the first direction D1, the base R3 at least partially overlaps with the fourth side 3104 of the third area 31. In some embodiments, the third recess R may be located at approximately the middle of the first area 2100 in the third direction D3, and the edge angle of the third recess R may be an arc angle. That is, the base R3 is a straight line, and the sloped edge R of the first side R1 close to the base R3 11 is an arcuate line, and the remaining part is a straight line. The slope edge R of the second side R2 21In some other embodiments, the shape of the third recess R may be changed when viewed from the first direction D1. For example, as shown in FIG. 10C, the bottom edge R3 is an arcuate line, and the sloped edge R of the first side edge R1 is a straight line. 11 is an arcuate line, the remaining part is a straight line, and the slope edge R of the second side R2 21 As shown in Fig. 10D, the corners of the third recess R may be right angles, in which case the base R3, the first side R1, and the second side R2 are all straight lines.

[0092] The first conductive material area 2111 includes a first extension region 2112 and a second extension region 2113 formed to extend toward the third recess R in the third direction D3. When viewed from the first direction D1, the first extension region 2112 and the second extension region 2113 are provided on both sides of the third recess R and connected to the third recess R. When viewed from the first direction D1, the first extension region 2112 is connected between the fifth side 2101 and the first side edge R1 of the third recess R, and the second extension region 2113 is connected between the sixth side 2102 and the second side edge R2 of the third recess R. In some other embodiments, as shown in FIG. 10B , when viewed from the first direction D1, the first extension region 2112 and the second extension region 2113 may each be spaced apart from the third recess R in the third direction D3. By providing the first extension region 2112 and the second extension region 2113, it is possible to compensate for the reduction in thickness at the first conductive material layer 211 caused by providing the first recess 2110 in that position, thereby making the overall thickness of the electrochemical device 100 more uniform. When the first layer 50 is provided, the presence of the first extension region 2112 and the second extension region 2113 also increases the contact area between the first layer 50 and the first conductive material layer 211, thereby reducing the risk of wrinkles occurring in the first layer 50. Typically, the electrode sheet preparation process includes steps such as stirring the positive and negative electrode slurry, applying the electrode sheet, roll-pressing the electrode sheet, and dividing the electrode sheet. In the present application, the third recess R is provided in the first area 2100, and the first conductive material area 2111 extends toward the third recess R to form the first extension region 2112 and the second extension region 2113. This advantageously reduces the risk of wavy edges in the electrode sheet at the notches when the electrode sheet is divided (cut along the third direction D3) because the thickness of the electrode sheet at the notches is uniform. For ease of distinction, FIGS. 9 and 10A show the first extension region 2112 and the second extension region 2113 as having different filling forms compared to other regions of the first conductive material layer 211. However, this does not mean that the first extension region 2112 and the second extension region 2113 are formed using different active materials compared to other regions of the first conductive material layer 211, nor does it mean that there is no clear limit between them.

[0093] Furthermore, the size of the first extension region 2112 in the third direction D3 is defined as W1, and the size of the second extension region 2113 in the third direction D3 is defined as W2, where (W1 + W2) / T1 is 20% or greater. Here, (W1 + W2) / T1 reflects the size ratio of the third recess R in the third direction D3. The larger (W1 + W2) / T1, the smaller the size ratio of the third recess R. Therefore, by limiting the ratio of (W1 + W2) / T1, the reduction in the heat dissipation area of ​​the first area 2100 due to the provision of the third recess R is improved. As shown in FIGS. 9 and 10A , in some embodiments, the third recess R is provided at approximately the middle of the first area 2100 in the third direction D3, so that W1 is approximately equal to W2. In other embodiments, the third recess R may be biased toward one side of the first area 2100.

[0094] Because the first conductive material area 2111 of this embodiment further includes a first extension region 2112 and a second extension region 2113, if it is necessary to limit the size of the first conductive material area 2111 covered by the first layer 50, in some embodiments, in addition to defining the distance between the third end edge 2104 and the eighth edge 51 of the first area 2100 in the second direction D2 as L1 and the distance between the seventh edge 2103 and the eighth edge 51 as L3, the sizes of the first extension region 2112 and the second extension region 2113 covered by the first layer 50 may be further limited. Therefore, it is further defined that the sizes of the first extension region 2112 and the second extension region 2113 in the second direction D2 are the same and both are L2, and (L2 + L3) / L1 ≦ 30%. By defining (L2+L3) / L1, the size of the first conductive material area 2111 covered by the first layer 50 in the second direction D2 is reduced, i.e., the amount of active material that does not perform a capacitive function covered by the first layer 50 is reduced, and the impact of the first layer 50 on the capacitance of the electrochemical device 200 is reduced.

[0095] As shown in FIG. 10E, in another embodiment, the first extending region 2112 and the second extending region 2113 have different sizes in the second direction D2. Specifically, the size of the first extending region 2112 in the second direction D2 is L2, and the size of the second extending region 2113 in the second direction D2 is L2'. In this case, (0.5L2 + 0.5L2' + L3) / L1 may be limited to 30%. As shown in FIGS. 9 and 10A, in some embodiments, the distance between the first extending region 2112 and the first conductive plate 30 in the third direction D3 is W3, and the distance between the second extending region 2113 and the first conductive plate 30 is W4, where W1 > W3 and W2 > W4. This reduces the size ratio of the third recess R in the third direction D3, thereby improving the reduction in the heat dissipation area of ​​the first area 2100 caused by the provision of the third recess R. As shown in Figures 9 and 1OA, in some embodiments, W1 is approximately equal to W2 and W3 is approximately equal to W4.

[0096] 9 and 10A , in some embodiments, in the third direction D3, the first extending region 2112 includes a ninth side 2114, and the second extending region 2113 includes a tenth side 2115. The ninth side 2114 is an inner edge of the first extending region 2112, and both ends of the ninth side 2114 are connected to the first side R1 and the fifth side 2101. The tenth side 2115 is an inner edge of the second extending region 2113, and both ends of the tenth side 2115 are connected to the second side R2 and the sixth side 2102, respectively. That is, when viewed from the first direction D1, the first area 2100 connects the ninth side 2114 and the tenth side 2115. The ninth side 2114 and the tenth side 2115 are linear.

[0097] As shown in FIGS. 11 and 12, in some further embodiments, the ninth side 2114 and the tenth side 2115 may be arc-shaped and protrude outward away from the first area 2100. In this case, one end of the ninth side 2114 is connected to the first side R1. Compared with the embodiment shown in FIG. 10, the other end of the ninth side 2114 to which the fifth side 2101 is connected can move downward in the reverse direction of the second direction D2. At the same time, the area located between both ends of the ninth side 2114 protrudes outward and convexly away from the first area 2100 so that the ninth side 2114 forms an arc. Similarly, one end of the tenth side 2115 is connected to the second side R2. Compared with the embodiment shown in FIG. 10, the other end of the tenth side 2115 connected to the sixth side 2102 can move downward along the reverse direction of the second direction D2. At the same time, the area located between both ends of the tenth side 2115 protrudes outward and convexly away from the first area 2100 so that the tenth side 2115 forms an arc.

[0098] In some embodiments, in the second direction D2, the sizes of both the first extending area 2112 and the second extending area 2113 are both L2, the distance between the ninth side 2114 and the fourth side 3104 is L4, and L2 < L4. Here, L4 represents the distance between the end of the ninth side 2114 connected to the first side R1 and the fourth side 3104. L4 reflects the length exposed from the fourth side 3104 side of the first conductive plate 30 in the first area 2100. By defining L2 < L4, that is, L4 is relatively large, it is advantageous for increasing the heat dissipation area of the first conductive plate 30 and reducing the temperature rise during high-current charging.

[0099] As shown in FIG. 13, in yet another embodiment of the present application, an electrochemical device 300 is also provided. The difference from the electrochemical device 200 is that in the third direction D3, the first conductive plate 30 is displaced from the middle position of the first area 2100. In this case, W3 < W4. In some embodiments, W3 < W1. In some embodiments, W2 < W4.

[0100] Here, the electrochemical device 100 (or electrochemical devices 200, 300) of the present application includes all devices capable of causing electrochemical reactions. Specifically, the electrochemical device 100 includes all types of primary batteries, secondary batteries, fuel cells, solar cells, and capacitors (e.g., supercapacitors). Optionally, the electrochemical device 100 may be a lithium secondary battery, including a lithium metal secondary battery, a lithium ion secondary battery, a lithium polymer secondary battery, and a lithium ion polymer secondary battery.

[0101] As shown in FIG. 14, one embodiment of the present application further provides an electronic device 1 including the electrochemical device 100 (or the electrochemical device 200, 300).

[0102] Here, the electrochemical device 100 of the present application is applied to electronic devices 1 in various fields. In one embodiment, the electronic device 1 of the present application may be, but is not limited to, a notebook computer, a pen-input computer, a mobile personal computer, an e-book player, a mobile phone, a portable facsimile machine, a portable copier, a portable printer, a headset stereo earphone, a video recorder, a liquid crystal television, a portable vacuum cleaner, a portable CD player, a minidisc, a walkie-talkie, an electronic organizer, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, an automobile, a motorcycle, an electric-assisted bicycle, a bicycle, a lighting fixture, a toy, a game device, a clock, a power tool, a flash, a camera, a large-scale household storage battery, a lithium-ion capacitor, or the like.

[0103] The present invention will be described in detail below with reference to specific examples and comparative examples. Here, the present invention will be described with reference to a specific test method using a battery as an example of the electrochemical device.

[0104] [Examples 1 to 4 and Comparative Example 1] In the first electrode sheet after the cold pressing process, a first recess is formed in the first conductive material layer by laser cleaning, and the first area is exposed in the first recess. The first area does not have a third recess. A first conductive plate is then welded to the first area, with one welding point and an area of ​​the welding point S2. Specific values ​​for T1, T2, S1, S2, J1, J2, J3, and L3 / L1 are listed in Table 1. Conventional designs can be used for the second electrode sheet, separator, and electrolyte.

[0105] The first electrode sheet, separator, and second electrode sheet of Examples 1 to 4 and Comparative Example 1 were stacked and wound, placed in a housing, and then an electrolyte was injected to produce a battery with a size of 5.2 mm × 65.4 mm × 82.5 mm and a capacity of 5.0 Ah. Then, each battery was subjected to rapid charging. Specifically, the charging flow included the following steps.

[0106] (1) Charge to 4.25V at a constant current of 2.0C, then discharge at a constant voltage to 1.5C. (2) Allow to rest for 5 minutes. (3) Charge to 4.38V at a constant current of 1.5C, then discharge at a constant voltage to 1.0C. (4) Allow to rest for 5 minutes. (5) Charge to 4.43V at a constant current of 1.0C, then discharge at a constant voltage to 0.05C. (6) Allow to rest for 5 minutes. Before charging, the temperature near the first conductive plate was measured as T1 using a multi-point thermometer. After charging was completed, the temperature near the first conductive plate was measured as T2 using a multi-point thermometer. The temperature rise Δt = T2 - T1. This result is recorded in Table 1. It should be noted that battery charging current is generally referenced by a multiplier C, where C is a value corresponding to the battery capacity. For example, if the battery capacity is 5.0Ah, then 1C corresponds to 5.0A, and 2C corresponds to 10.0A.

[0107] JPEG2026016735000002.jpg90170

[0108] The data in Table 1 show that, compared to Comparative Example 1, the batteries of Examples 1-4 satisfy the heat dissipation coefficient K≧30%, and therefore the temperature rise of the battery after rapid charging is smaller. Also, the larger the heat dissipation coefficient, the smaller the temperature rise of the battery. On the other hand, although the heat dissipation coefficients of Examples 2-3 are the same, the temperature rise in Example 2 is relatively small because L3 / L1 is relatively small.

[0109] Examples 5-11 The difference from Examples 1-4 is that in Examples 5-9, the third recess is provided in the first area, and the specific values ​​of T1, T2, S1, S2, J1, J2, J3, and (L2+L3) / L1 are also different, and are recorded in Table 2.

[0110] The difference from Example 5 is that the values ​​of (L2+L3) / L1 in Examples 10-11 are different and are recorded in Table 3.

[0111] The first electrode sheet, separator, and second electrode sheet of Examples 5-9 were stacked and wound, placed in a housing, and then an electrolyte was injected to produce a battery measuring 5.40 mm x 80.3 mm x 70.7 mm and with a capacity of 5.2 Ah. Each battery was then rapidly charged. Specifically, the charging process included the following steps:

[0112] (1) Charge to 4.25V at a constant current of 2.0C, then discharge at a constant voltage to 1.5C. (2) Leave to rest for 5 minutes. (3) Charge to 4.38V at a constant current of 1.5C, then discharge at a constant voltage to 1.0C. (4) Leave to rest for 5 minutes. (5) Charge to 4.43V at a constant current of 1.0C, then discharge at a constant voltage to 0.05C. (6) Leave to rest for 5 minutes. Measure the temperature rise Δt near the first conductive plate before and after charging, and record the results in Table 2.

[0113] JPEG2026016735000003.jpg94170

[0114] From the data in Table 2, it can be seen that the batteries of Examples 5-9 satisfy the heat dissipation coefficient K≧30%, and therefore the temperature rise of the battery after fast charging is smaller, and the larger the heat dissipation coefficient, the smaller the temperature rise of the battery.

[0115] The first electrode sheet, separator, and second electrode sheet of Examples 5, 10, and 11 were stacked and wound, placed in a housing, and then an electrolyte was injected to produce a battery measuring 5.2 mm x 65.4 mm x 82.5 mm and having a capacity of 5.0 Ah. Each battery was then rapidly charged. Specifically, the charging process included the following steps:

[0116] (1) Charge at a constant current of 2.0C to 4.05V, then discharge at a constant voltage to 1.6C. (2) Leave to rest for 5 minutes. (3) Charge at a constant current of 1.6C to 4.25V, then discharge at a constant voltage to 1.2C. (4) Leave to rest for 5 minutes. (5) Charge at a constant current of 1.2C to 4.35V, then discharge at a constant voltage to 0.8C. (6) Leave to rest for 5 minutes. (7) Charge at a constant current of 0.8C to 4.45V, then discharge at a constant voltage to 0.05C. (8) Leave to rest for 5 minutes. Measure the temperature rise Δt near the first conductive plate before and after charging, and record the results in Table 3.

[0117] JPEG2026016735000004.jpg75170

[0118] As is clear from the data in Table 3, Examples 5, 10-11 have the same heat dissipation coefficient, but compared to Example 10, Examples 5 and 11 satisfy (L2+L3) / L1≦30%, so the temperature rise is relatively low, and Example 5 has the smallest value of (L2+L3) / L1, so the temperature rise is also the smallest.

[0119] Examples 12 to 14 The difference from Example 5 is that the specific values ​​of T1, T2, S1, S2, J1, J2, J3, (L2+L3) / L1, and (W1+W2) / T1 in Examples 12-14 are different and are recorded in Table 4.

[0120] The first electrode sheet, separator, and second electrode sheet of Examples 5, 12, and 14 were stacked and wound, placed in a housing, and then an electrolyte was injected to produce a battery measuring 3.77 mm x 62.0 mm x 141.0 mm and having a capacity of 5.2 Ah. Each battery was then rapidly charged. Specifically, the charging procedure was as follows: (1) Charge to 4.2 V at a constant current of 1.8 C, then discharge to 0.7 C at a constant voltage. (2) Allow to stand for 5 minutes. (3) Charge to 4.4 V at a constant current of 0.7 C, then discharge to 0.05 C at a constant voltage. (4) Allow to stand for 5 minutes. The temperature rise ΔT near the position of the first conductive plate was measured before and after charging, and the results are recorded in Table 4.

[0121] JPEG2026016735000005.jpg135170

[0122] From the data in Table 4, it can be seen that the heat dissipation coefficient K and (L2+L3) / L1 values ​​of Example 5 are the same as those of Example 12, but the value of (W1+W2) / T1 is relatively large, resulting in a relatively low temperature rise. Compared to Example 14, the heat dissipation coefficient K and (L2+L3) / L1 values ​​of Example 13 are the same as those of Example 14, but the value of (W1+W2) / T1 is relatively large, resulting in an even lower temperature rise.

[0123] Finally, it should be noted that the above examples do not limit the technical proposal of the present application, but are merely for illustrating the technical proposal of the present application. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the scope of protection of the present application.

Claims

1. an electrode assembly and a first conductive plate; The electrode assembly has a wound structure and includes a first electrode sheet; the first electrode sheet includes a first conductive layer having opposing first and second surfaces, and a first conductive material layer provided on the first surface, the first surface including a first area, the first conductive material layer including a first conductive material area, the first conductive material area surrounding the first area forming a first recess, the first area being exposed in the first recess, the first conductive plate being connected to the first area and protruding from the first electrode sheet, the first conductive plate including a third area and a fourth area connected to each other, a direction perpendicular to the third area being defined as a first direction, in the first direction, a projection of the third area being located within a projection of the first area and a projection of the fourth area being located outside a projection of the first area, the third area including a connection area, and the first conductive plate being connected to the first area via the connection area; When viewed from the first direction, the third area includes a first side, a second side, a third side, and a fourth side, the first side and the second side are opposite to each other, the third side and the fourth side are opposite to each other, and the fourth side is connected to the fourth area, the first area includes a fifth side, a sixth side, and a seventh side, and when an extension direction of the third area is defined as a second direction, the seventh side and the third side are arranged in order in the second direction, and the fifth side, the first side, the second side, and the sixth side are arranged in order in the third direction, and the first direction, the second direction, and the third direction are perpendicular to each other, projections of the first area and the third area in the first direction are both rectangular; the fourth side is a boundary line between the third area and the fourth area, The dimension of the third area in the third direction is T １ and the dimension of the third area in the second direction is T ２ and the area of ​​the projection of the third area in the first direction is S １ and the area of ​​the projection of the connection area in the first direction is S ２ and the distance between the first side and the fifth side is J １ and the distance between the second side and the sixth side is J ２ and the distance between the third side and the seventh side is J ３ When defined as 30%≦S ２ / S １ + (J １ +J ２ +J ３ ) / (T １ +T ２ )≦75%.

2. 2. The electrochemical device of claim 1, wherein the first electrode sheet further includes a second conductive material layer provided on the second surface, the second surface including a second area, the second conductive material layer including a second conductive material area surrounding the second conductive material area to form a second recess, the second area being exposed to the second recess, and a projection of the first area and a projection of the second area at least partially overlapping in the first direction.

3. The electrochemical device of claim 2, further comprising a first layer adhered to the third area, the first layer comprising an insulating material, and in the first direction, a projection of the third area is located within a projection of the first layer.

4. 4. The electrochemical device of claim 3, wherein the first layer is further adhered to the first conductive material area, and in the first direction, the projection of the first area lies within the projection of the first layer.

5. 5. The electrochemical device of claim 4, further comprising a second layer containing an insulating material, the second layer being adhered to the second conductive material area, and the projection of the second area in the first direction being located within the projection of the second layer.

6. When viewed from the first direction, the first layer includes an eighth side, and in the second direction, the seventh side is provided between the eighth side and the third side; the fifth side and the sixth side face each other in the third direction, the seventh side connects both ends where the fifth side and the sixth side are connected, the seventh side faces a third end side of the first area in the second direction, In the second direction of the first area, the distance between the third end side opposite to the seventh side and the eighth side is defined as L １ and the distance between the seventh side and the eighth side is L ３ When defined as ３ / L １ 5. The electrochemical device according to claim 4, wherein the solubility is ≦30%.

7. a third recess is provided at an edge of the first area in the second direction, and the first conductive material area includes a first extension region and a second extension region formed to extend toward the third recess; 5. The electrochemical device according to claim 4, wherein the first extension region and the second extension region are provided on both sides of the third recess when viewed from the first direction.

8. When viewed from the first direction, the first layer includes an eighth side, and in the second direction, the seventh side is provided between the eighth side and the third side; The first extension region and the second extension region are both rectangular, The distance between the edge of the first area in the second direction and the eighth side is L １ The first extension region and the second extension region have the same size in the second direction and are both L ２ and the distance between the seventh side and the eighth side is L ３ When defined as (L ２ +L ３ ) / L １ 8. The electrochemical device of claim 7, wherein the solubility is ≦30%.

9. When viewed along the first direction, the first conductive material layer includes a first side edge and a second side edge that respectively face the first conductive plate in a third direction perpendicular to the second direction, and the first conductive material layer includes a tenth side edge that contacts the second side edge and the sixth side edge, In the third direction, the distance from the first side edge to the fifth side edge is defined as W １ and the distance from the second side to the tenth side is W ２ When defined as (W １ +W ２ ) / T １ 8. The electrochemical device of claim 7, wherein the solubility is ≧20%.

10. When viewed along the first direction, the first conductive material layer includes a first side edge and a second side edge that respectively face the first conductive plate in a third direction perpendicular to the second direction, and the first conductive material layer includes a tenth side edge that contacts the second side edge and the sixth side edge, In the third direction, the distance from the first side edge to the fifth side edge is defined as W １ and the distance from the second side to the tenth side is W ２ and the distance from the first conductive plate to the first side edge is W ３ and the distance from the first conductive plate to the second side edge is W ４ When defined as such, it satisfies at least one of the following conditions: W ３ <W １ ;W ２ <W ４ ;W ３ <W ４ 、 8. The electrochemical device according to claim 7.

11. In the third direction, the first extension region and the second extension region include a ninth side and a tenth side, respectively, and the first area is connected to the ninth side and the tenth side, respectively; 8. The electrochemical device according to claim 7, wherein the ninth side and the tenth side are linear or arc-shaped.

12. In the second direction, the size of the first extension region and / or the second extension region is L ２ and the distance between the ninth side and the fourth side is L ４ That is, L ２ <L ４ and L ４ represents the distance between the end of the ninth side connected to the first side edge and the fourth side, and reflects the length of the first area exposed from the fourth side of the first conductive plate.

13. L １ 9. The electrochemical device according to claim 6, wherein the range of .gtoreq..times ...

14. 6. The electrochemical device of claim 5, further comprising a third layer and a fourth layer, both of which comprise insulating materials, wherein in the first direction, the first layer is disposed between the first conductive plate and the third layer, and the second layer is disposed between the first conductive plate and the fourth layer.

15. 15. The electrochemical device of claim 14, wherein the electrode assembly further includes a second electrode sheet, and at least one of the third layer or the fourth layer is adhered to the second electrode sheet.

16. 6. The electrochemical device according to claim 5, wherein an edge of at least one of the first layer or the second layer extends beyond an edge of the first electrode sheet in the second direction.

17. The connection area is welded to the first area, the connection area includes a plurality of weld points, and the area S ２ 2. The electrochemical device according to claim 1, wherein the area of ​​the welds is the sum of the areas of the projections of the plurality of welds in the first direction.

18. the electrode assembly further includes a second electrode sheet and a separator, and the first electrode sheet, the separator, and the second electrode sheet are stacked and wound to form the electrode assembly; the electrode assembly includes a plurality of stacked first segments, a plurality of stacked first bent segments, a plurality of stacked second segments, and a plurality of stacked second bent segments; the first segment, the first bent segment, the second segment, and the second bent segment are connected in sequence in a winding direction of the electrode assembly, the first conductive plate is located on the first segment; the plurality of first segments and the plurality of second segments are all straight line segments, a connection point between the first segment located at the outermost side of the electrode assembly and the first bent segment located at the outermost side of the electrode assembly is a first end; a connection point between the first bent segment located at the outermost side of the electrode assembly and the second segment located at the outermost side of the electrode assembly is a second end; 2. The electrochemical device according to claim 1, wherein the second end is a terminal portion of the rightmost bent side of the first bent segment in the winding direction.

19. The electrochemical device further includes a housing, the housing including a body portion for accommodating the electrode assembly and a sealing edge connected to the body portion; 2. The electrochemical device of claim 1, wherein the sealing edge includes a polymer layer, and the fourth area protrudes from the housing through the polymer layer.

20. An electronic device comprising the electrochemical device according to any one of claims 1 to 19.

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