Electrochemical devices and electronic devices
By setting the number of tabs M in the electrochemical device to be less than the number of electrode layers N, and by adopting a U-shaped tab structure and a bonding welding area, the problem of electrochemical devices being unable to balance high-rate charging and discharging and safety is solved, thus improving both safety and performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NINGDE AMPEREX TECHNOLOGY LTD
- Filing Date
- 2021-06-23
- Publication Date
- 2026-06-09
AI Technical Summary
Electrochemical devices struggle to balance high-rate charge/discharge performance with safety performance.
Design an electrochemical device in which the number of tabs M is less than the number of electrode layers N, the tabs are located on both sides of the winding center plane, the tab structure is U-shaped, and adhesives and welding areas are used to stabilize the tab connection, reduce the risk of reverse insertion, and improve safety.
The process of folding and welding the tabs has been simplified, improving the safety and charge/discharge rate of the electrochemical device and reducing manufacturing costs.
Smart Images
Figure CN117276816B_ABST
Abstract
Description
[0001] This application is a divisional application of application number 202110698548.8, filed on June 23, 2021, entitled "Electrochemical Device and Electronic Device". Technical Field
[0002] This application relates to the field of energy storage technology, and more particularly to an electrochemical device and an electronic device having the electrochemical device. Background Technology
[0003] With the increasing popularity of consumer electronics products such as laptops, mobile phones, handheld game consoles, tablets, power banks, drones, and electric vehicles, people are demanding more and more stringent requirements for electrochemical devices (such as lithium-ion batteries).
[0004] However, electrochemical devices struggle to balance high-rate charge / discharge performance with safety performance. Summary of the Invention
[0005] Given the shortcomings of existing technologies, it is necessary to propose an electrochemical device.
[0006] Additionally, it is necessary to provide an electronic device having the electrochemical device.
[0007] This application provides an electrochemical device, including a housing, an electrode assembly disposed within the housing, a first tab group, and an adapter electrically connected to the first tab group and extending from the housing. The electrode assembly has a wound structure and includes a first electrode plate. The first tab group includes M first tabs, which are connected to the first electrode plates. The thickness direction of the electrode assembly is defined as a first direction. In the first direction, the electrode assembly includes N layers of first electrode plates, where N is greater than M and M > N / 2. The M first tabs are respectively connected to the first electrode plates. A plane passing through the winding center axis of the electrode assembly and perpendicular to the first direction is defined as a winding center plane. In the first direction, the M first tabs are disposed on both sides of the winding center plane. The first tab group includes a first connecting portion connecting to the adapter and a second connecting portion connecting to the first electrode plate. Each first tab includes a first part and a second part that are interconnected. The M first parts are stacked to form the first connecting portion, and the M second parts form the second connecting portion. Some of the second parts are connected to the side of the first connecting portion facing the electrode assembly.
[0008] This application sets the number M of first tabs to be less than the number N of first electrode layers, which helps reduce the difficulty of folding and soldering the tabs and simplifies the manufacturing process. Secondly, the M first tabs are respectively connected to M layers of the N first electrode layers. While ensuring the first tabs are located on both sides of the winding center plane, the number M of first tabs can be changed according to requirements, thus allowing adjustment of the electrode internal resistance and enabling the electrochemical device to meet different charge / discharge rate requirements. Thirdly, since part of the first tab of the second connection portion is connected to the side of the first connection portion facing the electrode assembly, the limiting effect of this part of the first tab makes the position of the first connection portion more stable and less prone to inverted insertion into the electrode assembly. Therefore, it can improve the contact short circuit problem caused by inverted insertion of the tabs and improve the safety of the electrochemical device.
[0009] In some possible implementations, in the first direction, first electrode plates connected to first tabs and first electrode plates not connected to first tabs are alternately arranged. Compared to an electrochemical device with tab structures on one side of the winding center surface, the alternating arrangement of first tabs on the first electrode plates, such that some first tabs are located on the side of the first connection portion facing the electrode assembly, reduces the risk of contact short circuits caused by inverted insertion of the first connection portion and improves safety due to the limiting effect of these first tabs. Simultaneously, since the number of first tabs is the same as in an electrochemical device with tab structures on one side of the winding center surface, the risk of increasing the number of first tabs to balance safety, leading to difficulties in tab bending and welding processes, is reduced.
[0010] In some possible implementations, the first connecting portion forms a U-shaped structure. The first connecting portion includes a first section, a second section, and a third section. The first section connects to an adapter, the second section connects to the second connecting portion, and the third section is bent and connected between the first and second sections. The adapter is at least partially located within the space defined by the U-shaped structure.
[0011] In some possible implementations, in the first direction, the outermost first electrode in the N layers of first electrodes is connected to a first tab, while the other outermost first electrode is not connected to a first tab.
[0012] In some possible implementations, the electrochemical device further includes a first adhesive and a second adhesive. The first adhesive adheres to the side of the first portion facing away from the electrode assembly. The second adhesive adheres to the side of the second portion facing away from the electrode assembly and to one surface of the electrode assembly in a first direction. In the first direction, the first adhesive is also disposed between two adjacent layers of the first electrode, and a second connection is located between the first adhesive and the second adhesive. The first and second adhesives reduce the risk of short circuits or leakage caused by burrs and solder marks piercing the housing at the first connection. The first adhesive includes a bend located on the side of the second portion facing the electrode assembly. The bend also provides restraint for the first connection, further reducing the risk of short circuits caused by inverted insertion of the first connection.
[0013] In some possible implementations, a first tab is connected to each layer of the first electrode sheet located between the first adhesive member and the second adhesive member. This allows for a further increase in the number of first tabs, thereby improving the charge / discharge rate of the electrochemical device.
[0014] In some possible implementations, M first tabs are welded together to form a welding area in the second section. A bend is provided on the side of the welding area facing the electrode assembly. Since the M first tabs are welded and fixed in the welding area of the second section, the risk of the first tabs separating from each other in the second section, leading to inverted insertion of the first connection, can be reduced, further improving the safety of the electrochemical device.
[0015] In some possible implementations, the two outermost first pole pieces in the N-layer first pole pieces are each connected to a first tab.
[0016] In some possible implementations, the electrochemical device further includes a first adhesive and a second adhesive. The first adhesive adheres to the side of the first portion opposite to the electrode assembly and one surface of the electrode assembly in the first direction. The second adhesive adheres to the side of the second portion opposite to the electrode assembly and the other surface of the electrode assembly in the first direction. In the first direction, a second connection is located between the first adhesive and the second adhesive. The first and second adhesives can reduce the risk of short circuits or leakage caused by burrs and solder marks piercing the housing at the first connection.
[0017] In some possible implementations, the M first electrodes are welded together to form a welding zone in the second section. Since the M first electrodes are welded and fixed in the welding zone of the second section, the risk of the first electrodes separating from each other in the second section, leading to inverted insertion of the first connection, can be reduced, further improving the safety of the electrochemical device.
[0018] In some possible implementations, at least one of the first adhesive or the second adhesive is an insulating adhesive film.
[0019] In some possible implementations, the first electrode includes a current collector and an active material layer disposed on the surface of the current collector. The first electrode tab is integrally formed with the current collector.
[0020] This application also provides an electronic device, including the electrochemical device described above. Attached Figure Description
[0021] Figure 1 A front view of an electrochemical device provided according to an embodiment of this application.
[0022] Figure 2 for Figure 1 The electrochemical device shown is a cross-sectional view along line II-II after the casing has been removed.
[0023] Figure 3 for Figure 1 The electrochemical device shown is a cross-sectional view along line III-III after the casing has been removed.
[0024] Figure 4 for Figure 1 The electrochemical device shown is a cross-sectional view along IV-IV after the casing has been removed.
[0025] Figure 5A for Figure 1 The electrochemical device shown is a top view in some other embodiments after the casing has been removed.
[0026] Figure 5B for Figure 1 The electrochemical device shown is a cross-sectional view in some other embodiments after the casing has been removed.
[0027] Figure 6 for Figure 1 The electrochemical device shown is a cross-sectional view in some embodiments after the casing has been removed.
[0028] Figure 7A A top view of an electrochemical device provided for another embodiment of this application.
[0029] Figure 7B A cross-sectional view of an electrochemical device provided for another embodiment of this application.
[0030] Figure 8 A cross-sectional view of an electrochemical device provided in another embodiment of this application.
[0031] Figure 9 A cross-sectional view of an electronic device provided according to an embodiment of this application.
[0032] Explanation of main component symbols
[0033] Electronic device 1
[0034] Casing 10
[0035] Main body part 11
[0036] Edge sealing 12
[0037] Electrode assembly 20
[0038] Side surfaces 20a, 20b
[0039] First film 21
[0040] Second pole piece 22
[0041] Separator 23
[0042] First ear group 30
[0043] First pole ear 31
[0044] Second pole ear group 40
[0045] Second pole ear 41
[0046] First adapter 50
[0047] Second adapter 60
[0048] First adhesive component 70
[0049] Bending part 71
[0050] Second adhesive component 80
[0051] Electrochemical devices 100, 200, 300
[0052] First paragraph 201
[0053] Second paragraph 202
[0054] First bend section 203
[0055] Second bend section 204
[0056] First current collector 211
[0057] First active material layer 212
[0058] Second current collector 221
[0059] Second active material layer 222
[0060] First connecting part 301
[0061] Second connecting part 302
[0062] First Division 3011
[0063] Second Division 3012
[0064] Third Division 3013
[0065] Welding area 3014
[0066] Space S
[0067] Winding direction D
[0068] First direction D1
[0069] Second direction D2
[0070] Winding center axis C
[0071] Winding center surface P
[0072] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation
[0073] The technical solutions in the embodiments of this application are described clearly and in detail below. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the specification of this application is for the purpose of describing particular embodiments only and is not intended to limit this application.
[0074] The embodiments of this application will be described in detail below. However, this application may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided to provide a thorough and detailed understanding of this application to those skilled in the art.
[0075] Additionally, for brevity and clarity, the dimensions or thicknesses of various components and layers may be enlarged in the accompanying drawings. Throughout the text, the same numerical values refer to the same elements. As used herein, the terms "and / or" and "and / or" include any and all combinations of one or more of the associated enumerated items. Furthermore, it should be understood that when element A is referred to as "connecting" element B, element A may be directly connected to element B, or there may be an intermediate element C and element A and element B may be indirectly connected to each other.
[0076] Furthermore, when describing the implementation of this application, the word "may" refers to "one or more implementations of this application".
[0077] The technical terms used herein are for the purpose of describing particular embodiments and are not intended to limit this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It should be further understood that the term "comprising," as used in this specification, means the presence of the described 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.
[0078] Spatial terms, such as "above," may be used herein for convenience in describing the relationship between one element or feature and another element (or feature) or feature (or feature) illustrated in the figures. It should be understood that, in addition to the directions depicted in the figures, spatial terms are intended to include different orientations of the device or apparatus during use or operation. For example, if the device in the figure is flipped, an element described as "above" or "on" other elements or features would be oriented "below" or "under" other elements or features. Therefore, the exemplary term "above" can include both above and below orientations. It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, 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 element, component, region, layer, or portion. Therefore, a first element, component, region, layer, or portion discussed below may be referred to as a second element, component, region, layer, or portion without departing from the teachings of the exemplary embodiments.
[0079] Please see Figures 1 to 3 One embodiment of this application provides an electrochemical device 100, including a housing 10, an electrode assembly 20, a first tab assembly 30, a second tab assembly 40, a first adapter 50, and a second adapter 60. The electrode assembly 20, the first tab assembly 30, and the second tab assembly 40 are disposed within the housing 10.
[0080] like Figure 1 As shown, in some embodiments, the housing 10 can be a packaging bag encapsulated with a sealing film (such as aluminum-plastic film), meaning the electrochemical device 100 is a pouch battery. The housing 10 includes a body portion 11 for housing the electrode assembly 20 and a sealing edge 12 connected to the body portion 11. In other embodiments, the electrochemical device 100 is not limited to a pouch battery, but can also be a steel-cased battery or an aluminum-cased battery, etc., and this application does not impose any limitations.
[0081] like Figure 2 and Figure 3As shown, the electrode assembly 20 includes a first electrode 21, a second electrode 22, and a separating membrane 23 disposed between the first electrode 21 and the second electrode 22. The separating membrane 23 is used to prevent the first electrode 21 and the second electrode 22 from directly contacting each other, thereby reducing the risk of short circuit in the electrode assembly 20. Figure 2 As shown, the electrode assembly 20 has a wound structure, that is, the first electrode 21, the separator 23, and the second electrode 22 are sequentially stacked and wound to form the electrode assembly 20. The electrode assembly 20 has a winding center axis C perpendicular to the paper surface. The winding direction D is... Figure 2 The direction shown is counterclockwise rotation along the central axis C of the winding.
[0082] The first electrode 21 includes a first current collector 211 and a first active material layer 212 disposed on the first current collector 211. The second electrode 22 includes a second current collector 221 and a second active material layer 222 disposed on the second current collector 221. In some embodiments, the first electrode 21 can be a negative electrode, and the second electrode 22 can be a positive electrode. The first current collector 211 can be, but is not limited to, metal foils such as copper foil or nickel foil. The second current collector 221 can be, but is not limited to, metal foils such as aluminum foil or nickel foil. In other embodiments, the first electrode can be a positive electrode, and the second electrode 22 can be a negative electrode.
[0083] The first tab assembly 30 includes M first tabs 31 (M being a natural number greater than 1), and the M first tabs 31 are connected to the first electrode plate 21. Specifically, each of the M first tabs 31 is connected to the first current collector 211 of the first electrode plate 21. More specifically, the multiple first tabs 31 can be integrally formed with the first current collector 211 (i.e., the first tabs 31 are cut from the first current collector 211). The first adapter 50 is electrically connected to the first tab assembly 30 and extends from the sealing edge 12 of the housing 10 to connect to external components (not shown). The electrode assembly 20 also has a first direction D1 and a second direction D2. The first direction D1 is the thickness direction of the electrode assembly 20. The second direction D2 is the direction in which the first tabs 31 extend from the first electrode plate 21; for example, the second direction D2 is the length direction of the electrode assembly 20.
[0084] like Figure 2 and Figure 4 As shown, the second tab assembly 40 includes a plurality of second tabs 41, the polarities of which are opposite to those of the first tab 31. The plurality of second tabs 41 are connected to the second electrode 22; specifically, the plurality of second tabs 41 are connected to the second current collector 221 of the second electrode 22; more specifically, the plurality of second tabs 41 may be integrally formed with the second current collector 221. A second adapter 60 is electrically connected to the second tab assembly 40 and extends from the sealing edge 12 of the housing 10 to connect to external components.
[0085] like Figure 2 and Figure 3 As shown, in the first direction D1, a first current collector layer 211 and a first active material layer 212 provided on the surface of the first current collector layer 211 are defined as a first electrode sheet 21. The electrode assembly 20 includes N layers of first electrode sheets 21 (N is a natural number greater than 1), and N is greater than M. For the sake of simplicity, Figure 2 and Figure 3 only some of the first electrode sheets 21 in the electrode assembly 20 may be shown示例性, that is, another part of the first electrode sheets 21 is omitted. Therefore, it can be understood that the actual number of layers of the first electrode sheet 21 is not limited to that shown in the figure. Similarly, the number of layers of the second electrode sheet 22 is not limited to that shown in the figure. M first electrode tabs 31 are respectively connected to the first electrode sheets 21. That is, M first electrode tabs 31 are respectively connected to M layers among the N layers of first electrode sheets 21, and the other (N - M) layers among the N layers of first electrode sheets 21 are not connected with first electrode tabs 31. Define a plane passing through the winding central axis C of the electrode assembly 20 and perpendicular to the first direction D1 as the winding central plane P. In the first direction D1, M first electrode tabs 31 are provided on both sides of the winding central plane P.
[0086] Specifically, as Figure 2 shown, along the winding direction D, the electrode assembly 20 includes a first section 201, a first bending section 203, a second section 202, and a second bending section 204 connected in sequence. In some embodiments, the first section 201 and the second section 202 may be straight sections arranged in parallel. In other embodiments, the first section 201 and the second section 202 may also be bending sections, which is not limited in this application. The winding central plane P is provided between the first section 201 and the second section 202. Therefore, M first electrode tabs 31 are provided on both sides of the winding central plane P, indicating that some of the M first electrode tabs 31 are connected to the first electrode sheets 21 located in the first section 201, and another part of the M first electrode tabs 31 are connected to the first electrode sheets 21 located in the second section 202.
[0087] More specifically, when N / 2 < M < N, the M first electrode tabs 31 can be arbitrarily distributed on both sides of the winding central plane P. When 2 ≤ M ≤ N / 2, the number of first electrode tabs 31 on one side of the winding central plane P is greater than or equal to 1, and the number of first electrode tabs 31 on the other side of the winding central plane P is greater than or equal to 1.
[0088] As Figure 3As shown, the first electrode assembly 30 includes a first connecting portion 301 and a second connecting portion 302. The first connecting portion 301 connects to the first adapter 50, and the second connecting portion 302 connects between the first electrode 21 and the first connecting portion 301. Each first electrode 31 includes a first portion and a second portion that are interconnected. M first portions are stacked on top of each other to form the first connecting portion 301. In some embodiments, at least two of the M first portions that are in contact with each other can be considered as part of the first connecting portion 301. M second portions form the second connecting portion 302, and a portion of the second portion (i.e., a portion of the M second portions) connects to the side of the first connecting portion 301 facing the electrode assembly 20.
[0089] The structure of the second electrode group 40 is similar to that of the first electrode group 30, which will not be described in detail here.
[0090] Straight-out tabs occupy space at the head of the electrode assembly, reducing the energy density of the electrochemical device. Therefore, the tabs need to be bent before welding to the adapter. In electrochemical devices with a half-tab structure (only one tab is connected to each electrode ring, e.g., only the first electrode of the first section is connected to the first tab), when the adapter needs to be inserted into the housing to a predetermined position for welding with the bent tab, the bent tab is prone to inverting and entering the electrode assembly under the force of the adapter, posing a risk of short circuits or even smoke and fire during subsequent use, reducing the safety of the electrochemical device. In electrochemical devices with a full-tab structure (one tab connected to each electrode layer), the charge / discharge rate is improved, but the difficulty of bending and welding the tabs is increased, raising manufacturing costs.
[0091] In this application, a turn refers to starting from a point on the electrode assembly 20 as the starting end, moving along the winding direction D to another point as the ending end, with the ending end, the starting end, and the center of the turn all aligned on a straight line, and the starting end located between the ending end and the center of the turn. A turn forms two layers, meaning that a turn of the first electrode 21 includes two layers of first electrode 21.
[0092] The number M of first tabs 31 in this application is less than the number N of first electrode layers 21, which helps to reduce the difficulty of folding and welding the tabs and simplifies the manufacturing process. Secondly, M first tabs 31 are respectively connected to M layers of N first electrode layers 21. While ensuring that the first tabs 31 are located on both sides of the winding center plane P, the number M of first tabs 31 can be changed according to needs. Therefore, the internal resistance of the electrode can be adjusted, so that the electrochemical device 100 can meet different charge and discharge rate requirements. Thirdly, since part of the second part is connected to the side of the first connecting part 301 facing the electrode assembly 20, the limiting effect of this part of the second part makes the position of the first connecting part 301 in the second direction D2 more stable. When the first adapter 50 extends into the housing 10, it is less likely to be reversed under the action of the first adapter 50. Therefore, the contact short circuit problem caused by reverse insertion of the tabs can be improved, and the safety of the electrochemical device 100 can be improved. Furthermore, the insulating adhesive layer used in the prior art to prevent the reversed tabs from contacting the end face of the electrode assembly can be reduced, thus reducing costs.
[0093] like Figure 3 As shown, in some embodiments, the first connecting portion 301 forms a U-shaped structure. The first connecting portion 301 includes a first portion 3011, a second portion 3012 opposite to the first portion 3011, and a third portion 3013 bent and connected between the first portion 3011 and the second portion 3012. The first portion 3011 connects to the first adapter 50, and the second portion 3012 connects to the second connecting portion 302. The first connecting portion 301 defines a space S with an opening facing the first adapter 50. The first adapter 50 is at least partially disposed within the space S defined by the U-shaped structure and can be welded and fixed to the first portion 3011.
[0094] like Figure 3 As shown, further, in some embodiments, in the first direction D1, the first electrode 21 connected to the first tab 31 and the first electrode 21 not connected to the first tab 31 are alternately arranged. That is, the number M of the first tabs 31 is N / 2 rounded to the nearest integer, and the number of the first tabs 31 is approximately the same as that of the electrochemical device with a half-tab structure. Compared to the electrochemical device with a half-tab structure, since the second part of the first tab 31 is alternately arranged in N layers of first electrode 21, the second part of some of the first tabs 31 is located on the side of the first connection portion 301 facing the electrode assembly 20. The limiting effect of this second part reduces the risk of contact short circuit caused by the inverted insertion of the first connection portion 301 and improves safety. At the same time, since the number of the first tabs 31 is the same as that of the electrochemical device with a half-tab structure, the risk of increasing the number of the first tabs 31 due to the need to balance safety, which would lead to difficulties in the tab bending and welding process, is reduced.
[0095] Please see Figure 5A and Figure 5B In other embodiments, the number M of first tabs 31 is greater than N / 2, and the first tabs 31 can be connected to any M layers of the N first electrode plates 21. That is, the number M of first tabs 31 can be increased as needed. Therefore, compared to the case where the first electrode plates 21 connected to the first tabs 31 and the first electrode plates 21 not connected to the first tabs 31 are alternately arranged, the internal resistance of the first electrode plates 21 can be further reduced, and the charge / discharge rate requirement of the electrochemical device 100 can be improved.
[0096] like Figure 3 As shown, in some embodiments, the two outermost first electrode layers 21 of the N-layer first electrode 21 are respectively connected to first tabs 31. The electrochemical device 100 also includes a first adhesive 70 and a second adhesive 80. The first adhesive 70 adheres to the side of the first portion 3011 opposite to the electrode assembly 20 and one side surface 20a of the electrode assembly 20 in the first direction D1. In some embodiments, the side surface 20a of the electrode assembly 20 may be a first electrode 21, a separating membrane 23, or other adhesives (not shown). The second adhesive 80 adheres to the side of the second portion 3012 opposite to the electrode assembly 20 and the other side surface 20b of the electrode assembly 20 in the first direction D1. In some embodiments, the side surface 20b of the electrode assembly 20 may be a first electrode 21, a separating membrane 23, or other adhesives (not shown). In the first direction D1, a second connecting portion 302 is located between the first adhesive 70 and the second adhesive 80. It is understandable that burrs may be formed when the first current collector 211 is cut to form the first tab 31, and solder marks may also be formed when the first connecting part 301 is welded to the first adapter 50. These burrs and solder marks may puncture the housing 10, thereby causing a short circuit or leakage. By providing the first adhesive 70 and the second adhesive 80, the risk of burrs and solder marks from the first connecting part 301 puncturing the housing 10 and causing a short circuit or leakage can be reduced. The first adhesive 70 and / or the second adhesive 80 can be insulating adhesive tape.
[0097] Further, in some embodiments, in the first direction D1, the width of the first adhesive member 70 is greater than the width of the first connecting portion 301. In some embodiments, the difference between the width of the first adhesive member 70 and the width of the first connecting portion 301 is 1mm to 50mm. Further, in some embodiments, in the first direction D1, the width of the second adhesive member 80 is greater than the width of the first connecting portion 301. In some embodiments, the difference between the width of the second adhesive member 80 and the width of the first connecting portion 301 is 1mm to 50mm. In some embodiments, in the second direction D2, the length of the first adhesive member 70 bonded to the side surface 20a of the electrode assembly 20 is not less than 1mm, so that the first adhesive member 70 can be firmly bonded to the electrode assembly 20. In some embodiments, in the second direction D2, the length of the second adhesive member 80 bonded to the side surface 20b of the electrode assembly 20 is not less than 1mm, so that the second adhesive member 80 can be firmly bonded to the first electrode 21. In some embodiments, in the second direction D2, the first adhesive 70 extends beyond the edge of the electrode assembly 20 by at least 2 mm, so that the first adhesive 70 can be securely bonded to the first connecting portion 301. In some embodiments, in the second direction D2, the second adhesive 80 extends beyond the edge of the electrode assembly 20 by at least 2 mm, so that the second adhesive 80 can be securely bonded to the first connecting portion 301. It can be understood that, in order to sufficiently reduce the risk of direct contact between the first electrode 21 and the second electrode 22, in the second direction D2, the edge of the separator 23 extends beyond the edges of the first electrode 21 and the second electrode 22. Therefore, in the second direction D2, the edge of the electrode assembly 20 is generally the edge of the separator 23.
[0098] Please refer to Figure 6 In other embodiments, the M first tabs 31 can be welded together to form a welding area 3014 in the second portion 3012. It is understood that if the M first tabs 31 are not fixed together at the first connecting portion 301, the first tabs 31 of the first connecting portion 301 can easily separate under the action of the first adapter 50 when the first adapter 50 extends into the housing 10. In this application, because the M first tabs 31 are welded together in the welding area 3014 of the second portion 3012, the number of first tabs 31 in the second portion 3012 can be further reduced (e.g., ...). Figure 6 The separation of the first tab 31 on the right side of the first direction D1 in the first direction reduces the risk of the first connection portion 301 being inserted backwards, thus further improving the safety of the electrochemical device 100. In some embodiments, the welding area 3014 may be provided at one end of the second portion 3012 near the third portion 3013.
[0099] Please refer to Figure 7A and Figure 7BAnother embodiment of this application also provides an electrochemical device 200. The difference from the electrochemical device 100 is that, in the first direction D1, the outermost first electrode 21 of the N layers of first electrode 21 is connected to a first tab 31, while the other outermost first electrode 21 is not connected to a first tab 31.
[0100] At this time, the first adhesive 70 adheres to the side of the first portion 3011 facing away from the electrode assembly 20. In the first direction D1, the first adhesive 70 is also disposed between two adjacent electrode layers. The second adhesive 80 adheres to the side of the second portion 3012 facing away from the electrode assembly 20 and one surface 20b of the electrode assembly 20 in the first direction D1. In the first direction D1, the second connecting portion 302 is located between the first adhesive 70 and the second adhesive 80. At this time, the first adhesive 70 and the second adhesive 80 can also reduce the risk of short circuits or leakage caused by burrs from the first connecting portion 301 piercing the housing 10. The first adhesive 70 includes a bending portion 71, which is disposed on the side of the second portion 3012 facing the electrode assembly 20. Therefore, the bending portion 71 can also provide a restraining effect on the first connecting portion 301 in the second direction D2, further reducing the risk of contact short circuits caused by inverted insertion of the first connecting portion 301. Furthermore, in the first direction D1, the first adhesive 70 is disposed between two adjacent electrode layers, which can reduce the thickness in the second direction D2 and improve the energy density.
[0101] like Figure 7B As shown, further, each layer of the first electrode 21 located between the first adhesive member 70 and the second adhesive member 80 is connected to a first tab 31. In this way, the number of first tabs 31 can be further increased, thereby increasing the charge-discharge rate of the electrochemical device 100.
[0102] In some embodiments, the M first tabs 31 are welded together to form a welding area 3014 in the second portion 3012, thereby reducing the risk of the first connecting portion 301 being reversed due to the separation of the first tabs 31 at the second portion 3012. The bending portion 71 may be provided on the side of the welding area 3014 facing the electrode assembly 20.
[0103] Please refer to Figure 8 Another embodiment of this application also provides an electrochemical device 300. Unlike the electrochemical device 100, the first connecting portion 301 is not a U-shaped structure, but extends integrally along the second direction D2. During manufacturing, only the first tab assembly 30 needs to be bent at the connection between the first connecting portion 301 and the second connecting portion 302; the first connecting portion 301 itself does not need to be bent, thus simplifying the manufacturing process.
[0104] The electrochemical devices 100, 200, and 300 of this application include all devices capable of undergoing electrochemical reactions. Specifically, electrochemical devices 100, 200, and 300 include all types of primary batteries, secondary batteries, fuel cells, solar cells, and capacitors (e.g., supercapacitors). Optionally, electrochemical devices 100, 200, and 300 can be lithium secondary batteries, including lithium metal secondary batteries, lithium-ion secondary batteries, lithium polymer secondary batteries, and lithium-ion polymer secondary batteries.
[0105] Please see Figure 9 This application also provides an electronic device 1 in one embodiment, which includes an electrochemical device 100 (or electrochemical devices 200, 300). The electrochemical devices 100, 200, and 300 of this application are applicable to electronic devices 1 in various fields. In one embodiment, the electronic device 1 of this application may be, but is not limited to, a laptop computer, a pen input computer, a mobile computer, an e-book player, a portable telephone, a portable fax machine, a portable copier, a portable printer, a stereo headset, a video recorder, an LCD TV, a portable cleaner, a portable CD player, a mini CD-ROM, a transceiver, an electronic notebook, a calculator, a memory card, a portable recorder, a radio, a backup power supply, a motor, a car, a motorcycle, an electric bicycle, a bicycle, lighting fixtures, toys, game consoles, clocks, power tools, flashlights, cameras, household large-capacity batteries, and lithium-ion capacitors, etc.
[0106] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the scope of the technical solutions of this application.
Claims
1. An electrochemical device, comprising a housing, an electrode assembly disposed within the housing, a first tab assembly, and an adapter electrically connected to the first tab assembly and extending from the housing, wherein the electrode assembly is a wound structure and includes a first electrode plate, the first tab assembly includes M first tabs, and the first tabs are connected to the first electrode plates, wherein... The thickness direction of the electrode assembly is defined as the first direction. In the first direction, the electrode assembly includes N layers of first electrode sheets, where N is greater than M and M > N / 2, and M first electrode tabs are respectively connected to the first electrode sheets. A plane passing through the winding center axis of the electrode assembly and perpendicular to the first direction is defined as the winding center plane. In the first direction, M first electrode tabs are disposed on both sides of the winding center plane. The first electrode assembly includes a first connecting portion for connecting the adapter and a second connecting portion for connecting the first electrode. Each first electrode includes a first part and a second part that are connected to each other. M first parts are stacked on top of each other to form the first connecting portion, and M second parts form the second connecting portion. A portion of the second part is connected to the side of the first connecting portion facing the electrode assembly.
2. The electrochemical device as claimed in claim 1, wherein, The first connecting portion forms a U-shaped structure. The first connecting portion includes a first part, a second part, and a third part. The first part connects to the adapter, the second part connects to the second connecting portion, and the third part is bent and connected between the first part and the second part. The adapter is at least partially disposed within the space defined by the U-shaped structure.
3. The electrochemical device as described in claim 2, wherein, In the first direction, the first tab is connected to the outermost first electrode in the N layers of first electrode sheets, while the first tab is not connected to the other outermost first electrode sheet.
4. The electrochemical device as described in claim 3, wherein, The electrochemical device also includes: The first adhesive is bonded to the side of the first portion opposite to the electrode assembly; The second adhesive is used to bond the side of the second portion away from the electrode assembly and the side surface of the electrode assembly in the first direction. In the first direction, the first adhesive is further disposed between two adjacent layers of the first electrode sheet, and the second connecting portion is located between the first adhesive and the second adhesive. The first adhesive includes a bending portion, which is disposed on the side of the second portion facing the electrode assembly.
5. The electrochemical device as described in claim 4, wherein, M of the first tabs are welded together to form a welding area in the second portion, and the bent portion is located on the side of the welding area facing the electrode assembly.
6. The electrochemical device as claimed in claim 4, wherein, Each layer of the first electrode sheet between the first adhesive member and the second adhesive member is connected to a first electrode tab.
7. The electrochemical device as claimed in claim 2, wherein, The first tabs are respectively connected to the two outermost first electrodes in the N-layer first electrode.
8. The electrochemical device as claimed in claim 7, wherein, The electrochemical device also includes: The first adhesive is used to bond the side of the first portion away from the electrode assembly and the side surface of the electrode assembly in the first direction. The second adhesive bonding member bonds the side of the second portion opposite to the electrode assembly and the other side surface of the electrode assembly in the first direction, wherein the second connecting portion is located between the first adhesive bonding member and the second adhesive bonding member in the first direction.
9. The electrochemical device as claimed in claim 8, wherein, M of the first tabs are welded together to form a welding zone in the second portion.
10. The electrochemical device as claimed in claim 4 or 8, wherein, At least one of the first adhesive component or the second adhesive component is insulating adhesive paper.
11. The electrochemical device as claimed in claim 1, wherein, The first electrode includes a current collector and an active material layer disposed on the surface of the current collector, and the first electrode tab is integrally formed with the current collector.
12. An electronic device comprising the electrochemical device as claimed in any one of claims 1 to 11.