Electrochemical device and electronic equipment

Abstract

The utility model relates to electrochemical energy storage technical field discloses a kind of electrochemical device and electronic equipment, electrochemical device, including electrode assembly and first tab, electrode assembly includes first pole piece, second pole piece, and be located between diaphragm of first pole piece and second pole piece, first pole piece, diaphragm and second pole piece are stacked and are wound into cylindrical body along winding direction;The polarity of first pole piece and second pole piece is opposite;First pole piece includes the multiple first circle layers that sequentially distribute along the radial direction of electrode assembly;First tab includes first connecting portion and first leg, first connecting portion is stacked in one first circle layer, and first leg is extended in electrode assembly outside from first connecting portion;The length of first connecting portion along winding direction is greater than or equal to 35% of the circumference of the first circle layer connected by it, and less than or equal to 65% of the circumference of the first circle layer connected by it, so as to improve the situation that tab cuts pole piece.

Description

Technical Field

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

[0002] Cylindrical batteries are widely used in various fields due to their shape and manufacturing advantages.

[0003] The cells inside a cylindrical battery also need to be wound into a cylindrical shape. Due to the influence of the process, it is difficult to wind the cells into a perfectly cylindrical shape. During the winding process, the edges of the tabs are prone to shearing forces that can cut the electrode sheets. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes an electrochemical device that can improve the situation where the electrode tabs cut the electrode sheets.

[0005] This invention also proposes an electronic device having the above-mentioned electrochemical device.

[0006] An electrochemical device according to a first aspect of the present invention includes an electrode assembly and a first tab. The electrode assembly includes a first electrode, a second electrode, and a spacer membrane disposed between the first electrode and the second electrode. The first electrode, the spacer membrane, and the second electrode are stacked and wound into a cylindrical shape along a winding direction. The first electrode and the second electrode have opposite polarities. The first electrode includes a plurality of first rings distributed sequentially along the radial direction of the electrode assembly. The first tab includes a first connecting portion and a first leg. The first connecting portion is stacked on a first ring, and the first leg extends from the first connecting portion outside the electrode assembly. The length of the first connecting portion along the winding direction is ≥35% of the circumference of the first ring to which it is connected, and ≤65% of the circumference of the first ring to which it is connected.

[0007] The electrochemical device according to the embodiments of the present invention has at least the following beneficial effects: by configuring the first electrode tab to include a first connecting part and a first support leg, the first connecting part being stacked on a first layer after the first electrode sheet is wound, the first support leg being connected to the first connecting part and located on the outside of the electrode assembly, and the length of the first connecting part along the winding direction being ≥35% of the circumference of the first layer to which it is connected and ≤65% of the circumference of the first layer to which it is connected, in this way, during the winding of the electrode assembly, the force direction of the two sides of the first connecting part in the winding direction is approximately toward the central axis of the electrode assembly, thereby reducing the shear force of the two sides of the first connecting part in the winding direction, which helps to improve the situation where the two sides of the first connecting part are cut by the first electrode sheet under the action of shear force, thereby improving the situation where the first electrode sheet breaks.

[0008] According to some embodiments of the present invention, the number of first legs is at least two, and the at least two first legs are distributed at intervals along the winding direction, and both extend from the first connecting portion outside the electrode assembly.

[0009] According to some embodiments of the present invention, the length of the first leg along the winding direction is less than the length of the first connecting portion along the winding direction.

[0010] According to some embodiments of this utility model, the length of the first leg along the winding direction is ≥1 mm.

[0011] According to some embodiments of the present invention, along the axial direction of the electrode assembly, the end of the first connecting portion away from the first support foot is flush with the edge of the first electrode plate.

[0012] According to some embodiments of the present invention, the length of the first connecting portion along the winding direction is equal to 50% of the circumference of the first layer to which it is connected.

[0013] According to some embodiments of the present invention, the electrochemical device further includes a cylindrical shell, and the electrode assembly and the first electrode tab are both disposed inside the cylindrical shell; the cylindrical shell has a first conductive part, and a first leg is connected to the first conductive part; the first electrode includes a first current collector and a first active material layer, the first active material layer is connected to at least one side of the surface of the first current collector along the thickness direction, and a first connecting part is connected to the outermost first ring layer and to the surface of the first current collector along the radial side; wherein, the outermost second electrode covers the end of the outermost first electrode, and the length of the first connecting part along the winding direction is L=1 / 2*(d-2m-2w-4h)*π; or, the outermost first electrode covers the end of the outermost second electrode, and the length of the first connecting part along the winding direction is L=1 / 2*(d-2m-2h)*π; wherein, d is the outer circumferential diameter of the cylindrical shell, m is the thickness of the peripheral wall of the cylindrical shell, w is the thickness of the first current collector, and h is the thickness of the diaphragm.

[0014] According to some embodiments of the present invention, the second electrode includes a plurality of second rings distributed radially in sequence, with the first rings and second rings alternating; the electrochemical device also includes a second tab, which includes a second connecting portion and a second leg, the second connecting portion being stacked on a second ring; the second leg extending from the second connecting portion outside the electrode assembly; the length of the second connecting portion along the winding direction is ≥35% of the circumference of the second ring to which it is connected, and ≤65% of the circumference of the second ring to which it is connected.

[0015] According to some embodiments of the present invention, the length of the second connecting portion along the winding direction is equal to 50% of the circumference of the second layer to which it is connected.

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

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

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 A partial structural schematic diagram of the electrochemical device provided in an embodiment of this utility model is shown; Figure 2 This diagram shows the connection structure of the first electrode plate and the first electrode tab in the unfolded state according to an embodiment of the present invention; Figure 3 A partial structural schematic diagram of an electrochemical device in the relevant technology is shown; Figure 4 This diagram shows the connection structure of the second pole piece and the second pole tab in the unfolded state according to an embodiment of the present invention. Figure 5 This diagram illustrates the connection structure of the first electrode plate and the first electrode tab in an unfolded state according to another embodiment of the present invention. Figure 6 A schematic diagram of the connection structure of the second pole piece and the second pole tab in the unfolded state is shown in another embodiment of the present invention.

[0019] Figure label: Electrochemical device 100; electrode assembly 110; first electrode 111; first coil 1111; first current collector 1113; first active material layer 1115; diaphragm 113; second electrode 115; second coil 1151; second current collector 1153; second active material layer 1155; first tab 130; first connecting part 131; first support leg 133; second tab 150; second connecting part 151; second support leg 153; winding direction X. Detailed Implementation

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

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

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

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

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

[0025] Please see Figure 1 This application provides an electronic device, which includes an electrochemical device 100. The electronic device in this application is not particularly limited and can be any electronic device known in the prior art.

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

[0027] In some embodiments, the electrochemical device 100 includes any device in which an electrochemical reaction occurs to interconvert chemical energy and electrical energy, and specific, non-limiting examples include all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors. In particular, the electrochemical device 100 is a lithium secondary battery, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, or lithium-ion polymer secondary batteries.

[0028] The electrochemical device 100 can be cylindrical, such as a coin cell or other cylindrical battery.

[0029] Please see Figures 1 to 2 In some embodiments, the electrochemical device 100 includes an electrode assembly 110 and a first tab 130.

[0030] The electrode assembly 110 includes a first electrode 111, a second electrode 115, and a spacer 113 disposed between the first electrode 111 and the second electrode 115. The first electrode 111, the spacer 113, and the second electrode 115 are stacked and wound into a columnar shape along the winding direction X.

[0031] The first electrode 111 and the second electrode 115 have opposite polarities; one of the first electrode 111 and the second electrode 115 is a positive electrode, and the other is a negative electrode.

[0032] The first electrode 111 includes a plurality of first rings 1111 arranged sequentially along the radial direction of the electrode assembly 110. The diameter of each first ring 1111 is different, and the diameter of each first ring 1111 gradually increases from the inside to the outside along the radial direction. Understandably, the first electrode 111, the diaphragm 113 and the second electrode 115 are all approximately spiral-shaped after winding, and the plurality of first rings 1111 can be connected sequentially along the winding direction X.

[0033] As an example, a reference line is used, which connects the central axis of the electrode assembly 110 and the innermost end of the first electrode 111. This reference line can extend radially along the electrode assembly 110. Each first layer 1111 starts at the first reference line and ends at the same reference line after one turn.

[0034] The first tab 130 includes a first connecting portion 131 and a first support 133. The first connecting portion 131 is stacked on a first ring 1111. The first support 133 is connected to the first connecting portion 131 and is located on the outside of the electrode assembly 110. The first support 133 can be used to connect other conductive structures.

[0035] The first connecting portion 131 may be stacked on the inner surface of the innermost first layer 1111; or, the first connecting portion 131 may be stacked on the outer surface of the outermost first layer 1111; or, the first connecting portion 131 may be stacked on the inner or outer surface of other first layers 1111 between the innermost first layer 1111 and the outermost first layer 1111, and located between the first layer 1111 to which it is connected and the diaphragm 113.

[0036] As an example, the electrochemical device 100 may further include a cylindrical housing and a second tab 150, with the electrode assembly 110, the first tab 130, and the second tab 150 all disposed within the cylindrical housing. The second tab 150 may be partially connected to the second electrode 115 and located between the second electrode 115 and the diaphragm 113, and partially located outside the electrode assembly 110. The portion of the second tab 150 located outside the electrode assembly 110 may be used to connect other conductive structures. Specifically, the cylindrical housing may have a first conductive portion and a second conductive portion, a first support 133 may be connected to the first conductive portion, and the second tab 150 may be connected to the second conductive portion. The first conductive portion and the second conductive portion may be connected to an external circuit respectively, thereby forming a charge-discharge circuit. Understandably, the first conductive portion and the second conductive portion may be insulated from each other to avoid short circuits. The first support 133 may be directly connected to the first conductive portion or connected to the first conductive portion via a first conductive element. The second tab 150 may be directly connected to the second conductive portion or connected to the second conductive portion via a second conductive element.

[0037] Understandably, during the winding process of the electrode assembly 110, the first connecting portion 131 is wound together with the first electrode 111. After the first electrode 111 is wound, it forms multiple first rings 1111, thereby forming a structure in which the first connecting portion 131 is connected to one of the first rings 1111.

[0038] The length L of the first connecting portion 131 along the winding direction X is greater than or equal to 35% of the circumference of the first layer to which the first connecting portion 131 is connected, and less than or equal to 65% of the circumference of the first layer to which the first connecting portion 131 is connected. Thus, during the winding of the electrode assembly 110, the force direction of the first connecting portion 131 at both edges along the winding direction X (e.g., Figure 1 The dashed arrows in the diagram are generally oriented toward the central axis of the electrode assembly 110, which can reduce the shearing force on both sides of the first connecting portion 131. This helps to improve the situation where the two sides of the first connecting portion 131 are cut by the shearing force during the winding process, thereby improving the situation where the first electrode 111 breaks.

[0039] Specifically, during the winding of the electrode assembly 110, due to process limitations, it is often difficult to guarantee that the cylindrical body has absolute roundness. The actual shape of the wound cylindrical body usually deviates to some extent from a pure cylinder; for example, the actual shape of the cylindrical body is an elliptical cylinder. Based on this, related technologies (such as...) Figure 3 During the winding process, the electrode assembly (as shown) experiences force on both sides of the tab 11 along the winding direction (e.g., ...). Figure 3 The dashed arrows in the diagram show a significant inclination relative to the central axis of the electrode assembly, which makes the two sides of the tab 11 prone to large shearing forces. Since the two sides of the tab 11 are sharp or have burrs, they are easily cut by the shearing force. However, in this embodiment, by setting the length L of the first connecting portion 131 along the winding direction X to be ≥35% and ≤65% of the circumference of the first layer 1111 to which it is connected, the inclination angle of the force direction of the first connecting portion 131 along the winding direction X to the central axis of the electrode assembly 110 is small during winding. This results in virtually no shearing force or very small shearing force, thereby improving the situation where the first connecting portion 131 cuts the first electrode 111.

[0040] The circumference of the first layer 1111 can be the length of the first electrode 111 along the length direction of the electrode when the first electrode 111 is unfolded and laid flat. The length L of the first connecting portion 131 along the winding direction X can be the length of the first connecting portion 131 along the length direction of the electrode after the first connecting portion 131 is unfolded and laid flat. It can be understood that the length direction of the first electrode 111 in the unfolded and laid-flat state can be the winding direction X.

[0041] As an example, the circumference of the first connecting portion 131 along the winding direction X can be 35%, 40%, 50%, 62%, 65% of the circumference of the first layer 1111 to which the first connecting portion 131 is connected, or other percentage values ​​within any two of the above percentage values.

[0042] In some embodiments, the length of the first connecting portion 131 along the winding direction X is equal to 50% of the circumference of the first layer 1111 to which it is connected. This can better ensure that the force direction of the first connecting portion 131 on both sides of the winding direction X is positively oriented toward the central axis of the electrode assembly 110, which helps to further reduce the shear force and improve the situation where the first connecting portion 131 cuts the first electrode 111.

[0043] In some embodiments, the electrochemical device 100 may further include an electrolyte that can be filled within a cylindrical housing to wet the electrode assembly 110.

[0044] In some embodiments, there may be two diaphragms 113. One diaphragm 113 is located between the first electrode 111 and the second electrode 115 to separate the first electrode 111 and the second electrode 115. The other diaphragm 113 is located on the side of the first electrode 111 opposite to the second electrode 115, or the other diaphragm 113 is located on the side of the second electrode 115 opposite to the first electrode 111 to separate the first electrode 111 and the second electrode 115 after winding.

[0045] In some embodiments, the first electrode 111 may include a first current collector 1113 and a first active material layer 1115. The first active material layer 1115 may be connected to at least one side of the surface of the first current collector 1113 along the thickness direction. The first connecting segment may be connected to the surface of the first current collector 1113 along the radial side, thereby improving the situation where the first connecting portion 131 cuts the first current collector 1113 at both sides of the winding direction X.

[0046] As an example, when the first electrode 111 is unfolded and laid flat, the first current collector 1113 may have a first surface on one side along the thickness direction. The first surface may include a coated area and a blank area. The first active layer may be connected to the coated area, and the first connecting segment may be connected to the blank area. The coated area and the blank area may be distributed along the length direction, and the blank area may be located at one end of the current collector along the length direction. Alternatively, the first active material layer 1115 may have a groove to expose a portion of the first surface, and the portion of the first surface exposed through the groove can be the blank area. After the first electrode 111 is wound into the electrode assembly 110, the first surface may be the surface of the first current collector 1113 facing the center of the electrode assembly 110, or it may be the surface of the first current collector 1113 facing away from the center of the electrode assembly 110.

[0047] Understandably, the first current collector 1113 may also have a second surface on the side opposite to the first surface along the thickness direction, and the second surface may also be coated with a first active material layer 1115, and the first connecting segment may also be connected to the second surface.

[0048] It should be noted that after the first electrode 111 is wound into the electrode assembly 110, the thickness direction in the above example is approximately the radial direction of the electrode assembly 110.

[0049] Please see Figure 4 In some embodiments, the second electrode 115 includes a second current collector 1153 and a second active material layer 1155. The connection method of the second current collector 1153, the second active material layer 1155, and the second electrode tab 150 can refer to the first current collector 1113, the first active material layer 1115, and the first electrode tab 130 in the above embodiments (e.g., Figure 2 The connection method shown in the figure will not be elaborated further.

[0050] Please see Figure 2 In some embodiments, the first connecting portion 131 may have a first edge and a second edge spaced apart along the winding direction X, and may have a third edge and a fourth edge spaced apart along the axial direction of the electrode assembly 110. The first edge, the third edge, the second edge, the fourth edge and the first edge may be connected end to end in sequence, and the first leg 133 may be connected to the third edge.

[0051] The position of the first support 133 at the third edge can be flexibly set according to requirements.

[0052] As an example, the first foot 133 can be connected to the center of the third edge in the winding direction X.

[0053] As another example, the first leg 133 can be connected to the third edge, and in the winding direction X, the distance between the first leg 133 and the first edge can be less than the distance between the first leg 133 and the second edge.

[0054] As another example, the first leg 133 can be connected to the third edge, and in the winding direction X, the distance between the first leg 133 and the first edge can be greater than the distance between the first leg 133 and the second edge.

[0055] Please see Figures 1 to 2 In some embodiments, along the axial direction of the electrode assembly 110, the end of the first connection portion 131 away from the first foot 133 is flush with the edge of the first electrode 111, thereby improving the situation where the sharp corner formed between the end of the first connection portion 131 away from the first foot 133 and the side along the winding direction X cuts the first current collector 1113.

[0056] As an example, along the axial direction of the electrode assembly 110, the fourth edge is flush with the edge of the first electrode 111.

[0057] In some embodiments, the length of the first leg 133 along the winding direction X can be less than the length L of the first connecting portion 131 along the winding direction X, thereby reducing the length of the first leg 133 in the winding direction X. On the one hand, this reduces the space occupied by the first leg 133 in the cylindrical shell, allowing the cylindrical shell to hold more electrolyte. On the other hand, it also reduces the mechanical strength of the first leg 133, making it easier for the first leg 133 to deform and connect with the first conductive portion, thus reducing the connection difficulty.

[0058] Please see Figure 1 and Figure 5 In some embodiments, the number of first feet 133 is at least two, which can refer to two, three, four or other numbers.

[0059] At least two first legs 133 are spaced apart along the winding direction X and extend from the first connecting portion 131 outside the electrode assembly 110. Each first leg 133 can be connected to the first conductive portion, thereby forming multiple current paths between the first electrode 111 and the first conductive portion, which helps to improve the charging and discharging performance of the electrochemical device 100. Furthermore, when one of the first legs 133 is disconnected, for example, when the electrochemical device 100 is subjected to an impact, a drop, or other abnormal situation that causes the first leg 133 to disconnect, the remaining first legs 133 can still conduct normally, ensuring the safety performance of the electrochemical device 100 and extending the service life of the electrochemical device 100.

[0060] As an example, the first conductive part may include multiple first regions, and any two adjacent first regions may be connected to each other. Each first pin 133 may be connected to one first region.

[0061] In some embodiments, the length of the first leg 133 along the winding direction X is ≥1 mm, which helps to ensure that the first leg 133 has sufficient mechanical strength.

[0062] As an example, the length of the first leg 133 along the winding direction X can be 1 mm, 2 mm, 2.5 mm or other values.

[0063] Please see Figures 1 to 2 In some embodiments, the first connecting part 131 is connected to the outermost first ring layer 1111, so that the first connecting part 131 can be connected to one end of the first group along the winding direction X, without the need to set a groove on the first active material layer 1115 to place the first connecting part 131, which helps to retain more active material and improve the capacity of the electrochemical device 100.

[0064] In some embodiments, the outermost second electrode 115 may cover the end of the outermost first electrode 111.

[0065] As an example, the first electrode 111 can be a positive electrode, and the second electrode 115 can be a negative electrode. The length of the second electrode 115 along the winding direction X can be longer than the length of the first electrode 111 along the winding direction X, so that the outermost second electrode 115 can cover the end of the outermost first electrode 111 after winding. In this example, a separator 113 can be disposed between the first electrode 111 and the second electrode 115, and another separator 113 can be located on the side of the positive electrode facing away from the negative electrode, with winding starting with the positive electrode inside the negative electrode.

[0066] Wherein, the length L of the first connecting part 131 along the winding direction X is L=1 / 2*(d-2m-2w-4h)*π, where d is the outer circumferential diameter of the cylindrical shell, m is the thickness of the peripheral wall of the cylindrical shell, w is the thickness of the first current collector 1113, and h is the thickness of the diaphragm 113. This allows for a better determination of the length L of the first connecting part 131 along the winding direction X, which is beneficial for manufacturing the first tab 130.

[0067] Understandably, d-2m is approximately the inner diameter of the cylindrical shell, d-2m-2w-4h is approximately the diameter of the outermost first ring 1111 where the first connecting section is located, (d-2m-2w)*π is approximately the circumference of the first ring 1111 where the first connecting section is located, and 1 / 2*(d-2m-2w-4h)*π is approximately 50% of the circumference of the first ring 1111 where the first connecting section is located.

[0068] In some embodiments, the outermost first electrode 111 may cover the end of the outermost second electrode 115.

[0069] As an example, the first electrode 111 can be a negative electrode and the second electrode 115 can be a positive electrode. The length of the first electrode 111 along the winding direction X can be longer than the length of the second electrode 115 along the winding direction X, so that the outermost first electrode 111 can cover the end of the outermost second electrode 115 after winding.

[0070] The length L of the first connecting portion 131 along the winding direction X is L = 1 / 2 * (d - 2m - 2h) * π, which allows for a better determination of the length L of the first connecting portion 131 along the winding direction X, facilitating the manufacturing of the first electrode tab 130. Understandably, in this embodiment, since the first electrode 111 covers the second electrode 115, the diaphragm 113 covering the outermost first ring layer 1111 is only one layer; therefore, only 2h needs to be subtracted when calculating the diameter of the first ring layer 1111.

[0071] In some embodiments, the second electrode 115 includes a plurality of second rings 1151 arranged radially in sequence, the first rings 1111 and the second rings 1151 are alternately distributed, and any adjacent first rings 1111 and second rings 1151 can be separated by a diaphragm 113.

[0072] Please see Figure 1 and Figure 6 In some embodiments, the second tab 150 may include a second connecting portion 151 and a second foot 153.

[0073] The second connecting portion 151 can be stacked on a second ring 1151. The second support 153 extends from the second connecting portion 151 outside the electrode assembly 110. The length of the second connecting portion 151 along the winding direction X is greater than or equal to 35% of the circumference of the second ring to which it is connected, and less than or equal to 65% of the circumference of the second ring to which it is connected. Thus, during the winding of the electrode assembly 110, the force direction of the two sides of the second connecting portion 151 in the winding direction X is approximately toward the central axis of the column, thereby reducing the shear force on the two sides of the second connecting portion 151 in the winding direction X. This helps to improve the situation where the two sides of the second connecting portion 151 are cut by the shear force during the winding process, thereby improving the situation where the second electrode 115 breaks. For details, please refer to the first connecting portion in the above embodiment, which will not be repeated here.

[0074] The second connecting portion 151 may be stacked on the inner surface of the innermost second layer 1151; or, the second connecting portion 151 may be stacked on the outer surface of the outermost second layer 1151; or, the second connecting portion 151 may be stacked on the inner or outer surface of other second layers 1151 between the innermost and outermost second layers 1151, and located between the second layer 1151 to which it is connected and the diaphragm 113.

[0075] In some embodiments, the length of the second connecting portion 151 along the winding direction X is equal to 50% of the circumference of the second layer 1151 to which it is connected. This can better ensure that the force direction of the second connecting portion 151 on both sides of the winding direction X is positively oriented toward the central axis of the electrode assembly 110, which helps to further reduce the shear force and further improve the situation where the second connecting portion 151 cuts the second electrode 115.

[0076] In some embodiments, the second connecting portion 151 may be connected to the outermost second ring layer 1151. The length of the second connecting portion 151 along the winding direction X can be calculated with reference to the formula of the first connecting portion 131 in the above embodiments, and will not be repeated here.

[0077] In some embodiments, the length of the second leg 153 along the winding direction X can be less than the length of the second connecting portion 151 along the winding direction X, thereby reducing the length of the second leg 153 in the winding direction X. On the one hand, this reduces the space occupied by the second leg 153 in the cylindrical housing, allowing the cylindrical housing to hold more electrolyte. On the other hand, it also reduces the mechanical strength of the second leg 153, making it easier for the second leg 153 to connect with the second conductive portion and reducing the connection difficulty.

[0078] In some embodiments, the number of second legs 153 is at least two, which can refer to two, three, four or other numbers.

[0079] At least two second legs 153 are spaced apart along the winding direction X and extend from the second connecting portion 151 outside the electrode assembly 110. Each second leg 153 can be connected to the second conductive portion, thereby setting multiple current paths between the second electrode 115 and the second conductive portion, which helps to improve the charging and discharging performance of the electrochemical device 100. Furthermore, when one of the second legs 153 is disconnected, for example, when the electrochemical device 100 is subjected to an impact, a drop, or other abnormal conditions that cause the second leg 153 to disconnect, the remaining second legs 153 can still conduct normally, ensuring the safety performance of the electrochemical device 100 and extending the service life of the electrochemical device 100.

[0080] As an example, the second conductive part may include multiple second regions, and any two adjacent second regions may be connected to each other. Each second pin 153 may be connected to one second region.

[0081] In some embodiments, the length of the second leg 153 along the winding direction X is ≥1 mm, which helps to ensure that the second leg 153 has sufficient mechanical strength.

[0082] As an example, the length of the second leg 153 along the winding direction X can be 1 mm, 2 mm, 2.5 mm or other values.

[0083] As shown in Table 1, Table 1 presents the simulation results of multiple electrochemical devices 100. The diameter (i.e., the outer circumferential diameter of the cylindrical shell) of each electrochemical device 100 is 11 mm, and the circumferential wall thickness of the cylindrical shell is 0.12 mm. The first electrode 111 is the negative electrode, the second electrode 115 is the positive electrode, the thickness of the first current collector 1113 is 0.008 mm, and the thickness of the second current collector 1153 is 0.012 mm. Neither the first tab 130 nor the second tab 150 undergoes deburring. The circumference of the first ring 1111, where the first connecting part 131 is located, is approximately 34 mm. The simulation results are as follows: Table 1

[0084] As can be clearly seen from Table 1, when the length L of the first connecting portion 131 in the winding direction X is equal to 50% of the circumference of the first layer 1111 to which it is connected (as shown in Item 5), the probability of the first electrode 111 being cut by the first connecting portion 131 is 0. The closer the length L of the first connecting portion 131 in the winding direction X is to 50% of the circumference of the first layer 1111 to which it is connected, the smaller the probability of the first electrode 111 being cut by the first connecting portion 131 (as shown in Items 4 and 6). The further the length L of the first connecting portion 131 in the winding direction X is from 50% of the circumference of the first layer 1111 to which it is connected, the greater the probability of the first electrode 111 being cut by the first connecting portion 131 (as shown in Items 3 and 7).

[0085] In Table 1, numbers 1 and 2 represent simulation results of electrochemical devices in the prior art. The first electrode tab is a rectangular parallelepiped with a length of 2 mm or 3 mm in the winding direction X. Therefore, the length of the first connecting portion is also 2 mm or 3 mm. According to the simulation results in Table 1, when the length of the first connecting portion is 2 mm or 3 mm, the probability of the first electrode being cut by the first connecting portion is much higher than the probability of the first electrode 111 being cut by the first connecting portion 131 in numbers 4 to 6, and also higher than the probability of the first electrode 111 being cut by the first connecting portion 131 in numbers 3 and 7. Therefore, extending the length of the first connecting portion 131 can reduce the probability of the first electrode 111 being cut by the first connecting portion 131.

[0086] Therefore, based on the simulation results, setting the length of the first connecting part 131 in the winding direction X to be close to or equal to half the circumference of the first layer 1111 to which it is connected can effectively improve the situation where the first electrode 111 is cut by the first connecting part 131. When the length of the first connecting part 131 in the winding direction X is equal to 50% of the circumference of the first layer 1111 to which it is connected, the anti-cutting effect is the best.

[0087] In the electrochemical device 100 and electronic device provided in this application embodiment, by configuring the first tab 130 to include a first connecting portion 131 and a first support 133, the first connecting portion 131 is stacked on a first layer 1111 after the first electrode 111 is wound, and the first support 133 is connected to the first connecting portion 131 and located on the outside of the electrode assembly 110, the length L of the first connecting portion 131 along the winding direction X is greater than or equal to 35% of the circumference of the first layer 1111 to which it is connected, and less than or equal to 65% of the circumference of the first layer 1111 to which it is connected, in the process of winding the electrode assembly 110, the force direction of the first connecting portion 131 on both sides of the winding direction X is approximately toward the central axis of the electrode assembly 110, thereby reducing the shear force on both sides of the first connecting portion 131 on both sides of the winding direction X, which helps to improve the situation where the two sides of the first connecting portion 131 are cut by the first electrode 111 under the action of shear force, thereby improving the situation where the first electrode 111 is broken.

[0088] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An electrochemical device, characterized in that, include: An electrode assembly includes a first electrode, a second electrode, and a spacer film disposed between the first electrode and the second electrode. The first electrode, the spacer film, and the second electrode are stacked and wound into a columnar body along a winding direction. The first electrode and the second electrode have opposite polarities. The first electrode includes a plurality of first rings distributed sequentially along the radial direction of the electrode assembly. The first electrode tab includes a first connecting portion and a first support leg. The first connecting portion is stacked on a first coil, and the first support leg extends from the first connecting portion outside the electrode assembly. The length of the first connecting portion along the winding direction is ≥35% of the circumference of the first coil to which it is connected, and ≤65% of the circumference of the first coil to which it is connected.

2. The electrochemical device according to claim 1, characterized in that, The number of the first legs is at least two, and the at least two first legs are spaced apart along the winding direction and both extend from the first connecting portion outside the electrode assembly.

3. The electrochemical device according to claim 1, characterized in that, The length of the first leg along the winding direction is less than the length of the first connecting portion along the winding direction.

4. The electrochemical device according to claim 1, characterized in that, The length of the first leg along the winding direction is ≥1 mm.

5. The electrochemical device according to claim 1, characterized in that, Along the axial direction of the electrode assembly, the end of the first connection portion away from the first support foot is flush with the edge of the first electrode plate.

6. The electrochemical device according to any one of claims 1 to 5, characterized in that, The length of the first connecting portion along the winding direction is equal to 50% of the circumference of the first layer to which it is connected.

7. The electrochemical device according to claim 6, characterized in that, The electrochemical device further includes a cylindrical shell, and the electrode assembly and the first tab are both disposed inside the cylindrical shell; the cylindrical shell has a first conductive part, and the first support is connected to the first conductive part; the first electrode includes a first current collector and a first active material layer, and the first active material layer is connected to at least one surface of the first current collector along the thickness direction; the first connecting part is connected to the outermost first ring layer and connected to the first current collector; Wherein, the outermost second electrode sheet covers the end of the outermost first electrode sheet, and the length of the first connecting portion along the winding direction is L=1 / 2*(d-2m-2w-4h)*π; or, the outermost first electrode sheet covers the end of the outermost second electrode sheet, and the length of the first connecting portion along the winding direction is L=1 / 2*(d-2m-2h)*π; In this context, d is the outer circumferential diameter of the cylindrical shell, m is the thickness of the peripheral wall of the cylindrical shell, w is the thickness of the first current collector, and h is the thickness of the diaphragm.

8. The electrochemical device according to any one of claims 1 to 5, characterized in that, The second electrode includes a plurality of second concentric rings distributed sequentially along the radial direction, with the first and second concentric rings alternating; the electrochemical device further includes a second tab, which includes a second connection portion and a second leg, the second connection portion being stacked on one of the second concentric rings; the second leg extends from the second connection portion outside the electrode assembly; The length of the second connecting portion along the winding direction is ≥ 35% of the circumference of the second layer to which it is connected, and ≤ 65% of the circumference of the second layer to which it is connected.

9. The electrochemical device according to claim 8, characterized in that, The length of the second connecting portion along the winding direction is equal to 50% of the circumference of the second layer to which it is connected.

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

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