Electrode assembly, battery cell and electric equipment
By providing through holes and raised tabs on the composite current collector, the problem of welding energy loss is solved and the safety and reliability of the battery cell are improved.
Patent Information
- Application Number
- CN202510902995.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-01
- Publication Date
- 2025-09-12
AI Technical Summary
In the prior art, the welding energy loss of the composite current collector is serious, which easily leads to problems such as cold welding and over-welding, affecting the safety and reliability of the battery cell.
The design of the first pole piece and the pole ear is adopted, including setting a through hole on the composite current collector, the pole ear body and the rivet part are in contact with both sides of the composite current collector, and multiple protrusions are formed on the surface to increase the contact area and connection reliability.
It improves the safety and reliability of the battery cells, reduces the possibility of tab detachment and short circuit, and enhances the stability of the connection.
Smart Images
Figure CN120637501A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of battery technology, and in particular to an electrode assembly, a battery cell, and an electrical device. Background Art
[0002] With the rapid development of electronic information technology, various electronic devices are also developing towards intelligence and multi-functions, and the requirements for battery safety and reliability are becoming higher and higher.
[0003] Currently, composite current collectors typically consist of an insulating layer and two metal layers positioned on either side of the insulating layer. These two metal layers are welded to the two tabs to achieve electrical continuity. Welding energy is severely lost in the insulating layer, easily causing problems such as cold solder joints and over-soldering, impacting the safety and reliability of the battery cell. Summary of the Invention
[0004] The present application provides an electrode assembly, a battery cell, and an electrical device, which can improve the safety and reliability of the battery cell.
[0005] In a first aspect, the present application provides an electrode assembly, the electrode assembly comprising a first electrode piece and a first electrode tab, the first electrode piece comprising a first composite current collector, the first composite current collector having a first side and a second side opposite to each other along its thickness direction. The first composite current collector is provided with a first through hole extending along its thickness direction. The first electrode tab comprises a first main body and a first rivet portion, the first main body being provided on the first side, the first rivet portion protruding from the first main body and extending through the first through hole, and an end of the first rivet portion away from the first main body being pressed against the second side. A plurality of first protrusions are formed on the surface of the first main body, at least some of the first protrusions being in contact with the first side. A plurality of second protrusions are formed on the surface of the first rivet portion, at least some of the second protrusions being in contact with the second side.
[0006] In the above technical solution, the first composite current collector is provided with a first through hole extending through the first composite current collector in the thickness direction thereof, the first pole tab includes a first main body and a first rivet portion, the first main body is provided on the first side, the first rivet portion is protruded from the first main body and extends through the first through hole, and the end of the first rivet portion away from the first main body is pressed against the second side, so that the first main body can contact the first side of the first composite current collector to achieve electrical connection, and the first rivet portion can contact the second side of the first composite current collector to achieve electrical connection, thereby making the first side and the second side of the first composite current collector conductive through the first pole tab, and the connection method between the first composite current collector and the first pole tab is simple, the connection stability is high, and the first pole tab is not easy to separate from the first composite current collector and cause the battery cell to break. The safety and reliability of the battery cell can be improved by forming a plurality of first protrusions on the surface of the first body, at least part of the first protrusions are in contact with the first side, so that the first protrusion can fully contact the first side, increase the contact area between the first pole ear and the first side, improve the connection reliability between the first pole ear and the first side, and thus improve the safety and reliability of the battery cell; the safety and reliability of the battery cell can be improved by forming a plurality of second protrusions on the surface of the first riveted part, at least part of the second protrusions are in contact with the second side, so that the second protrusion can fully contact the second side, increase the contact area between the first pole ear and the second side, improve the connection reliability between the first pole ear and the second side, and thus improve the safety and reliability of the battery cell.
[0007] In some embodiments of the present application, along the thickness direction of the first composite current collector, the first body has a first region overlapping with the first composite current collector, the sum of the projected areas of all the first protrusions on the first region is S1, and the projected area of the first region is S2, satisfying 20%≤S1 / S2≤95%.
[0008] In the above technical solution, when S1 / S2 is greater than or equal to 20%, the area of the first protrusion on the first zone accounts for a larger proportion, which can make the contact area between the first protrusion and the first side larger, thereby making the connection reliability between the first pole ear and the first side higher, and thus improving the safety and reliability of the battery cell; when S1 / S2 is less than or equal to 95%, the spacing between adjacent first protrusions is larger, which facilitates the deformation of the first pole ear so that the first protrusion contacts the first side more closely, which is beneficial to improving the connection reliability between the first pole ear and the first side, and thus improving the safety and reliability of the battery cell; therefore, when 20%≤S1 / S2≤95%, the connection reliability between the first pole ear and the first side can be improved, thereby improving the safety and reliability of the battery cell.
[0009] In some embodiments of the present application, along the length direction of the first electrode tab, the length of the first protrusion is L1, satisfying 10μm≤L1≤500μm; and / or, along the thickness direction of the first composite current collector, the thickness of the first electrode tab is H1, the height of the first protrusion is H2, satisfying 5μm≤H2
[0010] In the above technical solution, when L1 is greater than or equal to 10μm, it is convenient to prepare the first protrusion, and the contact area between the first protrusion and the first side is larger, the connection reliability between the first pole ear and the first side is higher, and the safety and reliability of the battery cell can be improved; when L1 is less than or equal to 500μm, the number of first protrusions set on the first pole ear is greater, which is beneficial to the deformation of the first pole ear so that the first protrusion contacts the first side more closely, which is beneficial to improving the connection reliability between the first pole ear and the first side, and thus can improve the safety and reliability of the battery cell; therefore, when 10μm≤L1≤500μm, it is convenient to prepare the first protrusion, so that the contact area between the first protrusion and the first side is larger, and it is beneficial to the deformation of the first pole ear so that the first protrusion contacts the first side more closely, which is beneficial to improving the connection reliability between the first pole ear and the first side, and thus can improve the safety and reliability of the battery cell.
[0011] By setting H2 < H1, the first protrusion protrudes from the surface of the first tab, facilitating deformation of the first tab so that the first protrusion contacts and mates with the first side, thereby enhancing the connection between the first protrusion and the first side. When 5 μm ≤ H2 < H1, both the height of the first protrusion and the thickness of the first tab can be increased, facilitating the manufacture of the first tab, reducing the likelihood of the first tab bending and breaking, and enhancing the reliability of the connection between the first tab and the first composite current collector. When H2 < H1 ≤ 150 μm, both the height of the first protrusion and the thickness of the first tab can be reduced, reducing the thickness of the portion of the first tab that does not protrude from the first tab in the thickness direction of the first composite current collector or that protrudes from the first tab, thereby minimizing the impact on the overall thickness of the electrode assembly and facilitating improved energy density of the battery cell. Therefore, when 5 μm ≤ H2 < H1 ≤ 150 μm, both the height of the first protrusion and the thickness of the first tab can be increased, facilitating the manufacture of the first tab, reducing the likelihood of the first tab bending and breaking, improving the reliability of the connection between the first tab and the first composite current collector, and further facilitating improved energy density of the battery cell.
[0012] In some embodiments of the present application, along the length direction or width direction of the first composite current collector, the minimum spacing distance between two adjacent first protrusions is D1, and the maximum spacing distance between the two adjacent first protrusions is D2, satisfying 10μm≤D1≤D2≤500μm.
[0013] In the above technical solution, the first protrusion is a three-dimensional shape, so there are multiple distances between the two first protrusions. When D1≤D2, on the vertical plane in the thickness direction of the first composite current collector, the gap between the two adjacent first protrusions is rectangular or the spacing distance varies, which can facilitate the preparation of the first protrusion; when 10μm≤D1≤D2, the spacing distance between the two adjacent first protrusions is larger, which is convenient for bending the first pole ear and reduces the possibility of interference between the two adjacent first protrusions after the first pole ear is bent; when D1≤D2 ≤500μm, so that more first protrusions can be provided on the first pole tab, and the contact area between the first protrusion and the first side can be larger, which is beneficial to improving the connection reliability between the first pole tab and the first composite current collector, and improving the safety and reliability of the battery cell; therefore, when 10μm≤D1≤D2≤500μm, it can facilitate the bending of the first pole tab and reduce the possibility of interference between two adjacent first protrusions after the first pole tab is bent, and can also make the contact area between the first protrusion and the first side larger, which is beneficial to improving the connection reliability between the first pole tab and the first composite current collector, and improving the safety and reliability of the battery cell.
[0014] In some embodiments of the present application, a cross-sectional area of the first protrusion along the width direction of the first composite current collector gradually decreases toward the first side.
[0015] In the above technical solution, by gradually reducing the cross-sectional area of the first protrusion along the width direction of the first composite current collector toward the first side, the preparation of the first protrusion can be further facilitated, and the possibility of interference between two adjacent first protrusions after the first pole ear is bent is reduced, thereby reducing the possibility of damage to the first pole ear during bending and improving the safety of the battery cell.
[0016] In some embodiments of the present application, the first riveted portion includes a plurality of riveted segments arranged along the circumference of the first through hole, one end of each riveted segment is connected to the first body, and the other end passes through the first through hole and presses against the second side.
[0017] In the above technical solution, by making the first riveted portion include a plurality of riveted segments arranged along the circumference of the first through hole, one end of each riveted segment is connected to the first main body, and the other end passes through the first through hole and is pressed against the second side, the connection strength between the first pole ear and the first composite current collector can be improved, and the possibility of the first pole ear being separated from the first composite current collector and causing problems such as battery cell short circuit or first pole ear contacting and short circuiting with other components can be reduced, thereby improving the safety and reliability of the battery cell.
[0018] In some embodiments of the present application, the first tab includes a plurality of first rivet portions, and the plurality of first rivet portions are arranged at intervals along the length direction of the first tab.
[0019] In the above technical solution, by making the first pole tab include multiple first rivet portions, the connection strength between the first pole tab and the first composite current collector can be improved. By making the multiple first rivet portions arranged at intervals along the length direction of the first pole tab, the connection force between the first pole tab and the first composite current collector can be evenly distributed, further improving the connection strength between the first pole tab and the first composite current collector, reducing the possibility of the first pole tab detaching from the first composite current collector and causing problems such as battery cell short circuit or short circuit due to contact between the first pole tab and other components, and improving the safety and reliability of the battery cell.
[0020] In some embodiments of the present application, the first composite current collector includes a first insulating layer, a first metal layer, and a second metal layer, wherein the first metal layer and the second metal layer are respectively disposed on opposite sides of the first insulating layer along the thickness direction thereof, with the first metal layer being located on the first side and the second metal layer being located on the second side. The first protrusion contacts the first metal layer, and the second protrusion contacts the second metal layer.
[0021] In the above technical solution, the first protrusion is in contact with the first metal layer, and the second protrusion is in contact with the second metal layer, so that the first metal layer and the second metal layer can be electrically connected through the first tab.
[0022] In some embodiments of the present application, the first composite current collector includes a first insulating layer, a first metal layer, a second metal layer, and a metal foil. The first metal layer and the second metal layer are respectively disposed on opposite sides of the first insulating layer along its thickness direction, with the first metal layer located on the first side, the metal foil being disposed on the side of the second metal layer facing away from the first insulating layer, and the metal foil being located on the second side. The first protrusion contacts the first metal layer, and the second protrusion contacts the metal foil.
[0023] In the above technical solution, the metal foil is arranged on the side of the second metal layer facing away from the first insulating layer, the metal foil is located on the second side, the first protrusion contacts the first metal layer, and the second protrusion contacts the metal foil, so that the first metal layer and the second metal layer can be electrically connected through the first electrode ear and the metal foil, and the metal foil can reduce the possibility of the second protrusion piercing the second metal layer, thereby further improving the safety and reliability of the battery cell.
[0024] In some embodiments of the present application, the metal foil is provided with a second through hole penetrating along the thickness direction thereof, and the first riveted portion penetrates the first through hole and the second through hole and presses against the metal foil.
[0025] In the above technical solution, by providing the metal foil with a second through hole extending through the metal foil along its thickness direction, the first riveted portion can pass through the first through hole and the second through hole and press against the metal foil, thereby improving the preparation efficiency of the battery cell.
[0026] In some embodiments of the present application, the electrode assembly further comprises a second pole piece and a second pole tab, the second pole piece comprising a second composite current collector, the second composite current collector having a third side and a fourth side opposite to each other along its thickness direction. The second composite current collector is provided with a third through hole extending through its thickness direction. The second pole tab comprises a second main body and a second rivet portion, the second main body being provided on the third side, the second rivet portion being protruding from the second main body and extending through the third through hole, and an end of the second rivet portion away from the second main body being pressed against the fourth side. A plurality of third protrusions are formed on the surface of the second main body, at least some of the third protrusions being in contact with the third side. A plurality of fourth protrusions are formed on the surface of the second rivet portion, at least some of the fourth protrusions being in contact with the fourth side.
[0027] In the above technical solution, the second composite current collector is provided with a third through-hole extending through the thickness thereof, the second tab includes a second body and a second rivet, the second body is provided on the third side, the second rivet protrudes from the second body and extends through the third through-hole, and the end of the second rivet away from the second body abuts against the fourth side, so that the second body can contact the third side of the second composite current collector to achieve electrical connection, and the second rivet can contact the fourth side of the second composite current collector to achieve electrical connection, thereby enabling electrical connection between the third side and the fourth side of the second composite current collector through the second tab. Furthermore, the connection between the second composite current collector and the second tab is simple and stable, and the second tab is not easily separated from the second composite current collector, causing problems such as cell disconnection or short circuit due to contact between the second tab and other components, thereby improving the safety and reliability of the battery cell. Furthermore, a plurality of third protrusions are formed on the surface of the second body, with at least some of the third protrusions contacting the third side, so that the third protrusions can fully contact the third side, thereby increasing the contact area between the second tab and the third side, improving the connection reliability between the second tab and the third side, and thereby improving the safety and reliability of the battery cell. By forming a plurality of fourth protrusions on the surface of the second riveted portion, at least some of the fourth protrusions are in contact with the fourth side, so that the fourth protrusions can fully contact the fourth side, thereby increasing the contact area between the second pole tab and the fourth side, and improving the connection reliability between the second pole tab and the fourth side, thereby improving the safety and reliability of the battery cell.
[0028] In a second aspect, the present application provides a battery cell comprising the electrode assembly as described above.
[0029] In some embodiments of the present application, the battery cell includes a packaging bag, and the electrode assembly is housed in the packaging bag. Along the length of the first electrode tab, the first electrode tab has a first section and a second section, the first section being connected to the first composite current collector, and the second section extending out of the packaging bag. The first protrusion and the second protrusion are provided on the first section.
[0030] In the above technical solution, the first electrode tab has a first section and a second section along the length direction of the first electrode tab, the first section is connected to the first composite current collector, the second section extends out of the packaging bag, and the first protrusion and the second protrusion are arranged on the first section, so that the first composite current collector can be electrically connected to the first section through the first protrusion and the second protrusion, and the electrode assembly can be connected to the load of the electrical equipment through the second section, so as to realize power supply from the battery cell to the load.
[0031] In a third aspect, the present application provides an electrical device, comprising a battery cell as described above, the battery cell being used to provide electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can also be obtained based on these drawings.
[0033] Figure 1 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application; Figure 2 A schematic cross-sectional view of a portion of the structure of an electrode assembly provided in some embodiments of the present application; Figure 3 A schematic structural diagram of a first composite current collector of an electrode assembly provided in some embodiments of the present application; Figure 4 A schematic structural diagram of a first electrode tab of an electrode assembly provided in some embodiments of the present application; Figure 5 A schematic diagram of a partial structure of an electrode assembly provided in some embodiments of the present application; Figure 6 for Figure 4 A schematic diagram of the partial enlarged structure of the first tab A; Figure 7 A schematic structural diagram of an electrode assembly before connection between a first tab and a first composite current collector provided in some embodiments of the present application; Figure 8 Schematic cross-sectional views of a portion of the structure of an electrode assembly provided in some other embodiments of the present application; Figure 9 Schematic diagram of a partial structure of an electrode assembly provided in some other embodiments of the present application; Figure 10 Schematic diagram of the structure of the metal foil of the electrode assembly provided in other embodiments of the present application; Figure 11 A schematic diagram of the three-dimensional structure of a battery cell provided in some embodiments of the present application.
[0034] Icons: 10-electrode assembly; 100-first pole piece; 110-first composite current collector; 111-first through hole; 112-first insulating layer; 113-first metal layer; 114-second metal layer; 120-first active material layer; 121-first groove; 130-second active material layer; 131-second groove; 200-first pole tab; 200a-first surface; 200b-second surface; 201-first section; 202-second section; 203-seal; 210-first body; 211-first protrusion; 212-first Zone; 213-second zone; 220-first riveted portion; 221-second protrusion; 222-riveted section; 300-metal foil; 310-second through hole; 400-second pole piece; 410-second composite current collector; 411-third through hole; 500-second pole ear; 510-second main body; 511-third protrusion; 520-second riveted portion; 521-fourth protrusion; 600-diaphragm; 20-packaging bag; X-thickness direction of the first composite current collector; Y-length direction of the first composite current collector; Z-width direction of the first composite current collector. DETAILED DESCRIPTION
[0035] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions in the embodiments of this application will be clearly described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field are within the scope of protection of this application.
[0036] Unless otherwise defined, all technical and scientific terms used in this application have the same meanings as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.
[0037] The terms "first", "second" and the like in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order or a primary-secondary relationship.
[0038] References to "embodiments" in this application mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute an independent or alternative embodiment that is mutually exclusive of other embodiments.
[0039] In the embodiments of this application, the same reference numerals represent the same components, and for the sake of brevity, detailed descriptions of the same components in different embodiments are omitted. It should be understood that the thickness, length, width, and other dimensions of the various components in the embodiments of this application, as well as the overall thickness, length, width, and other dimensions of the integrated device shown in the drawings are merely illustrative and should not constitute any limitation on this application.
[0040] With the development of the new energy industry, battery cells are gradually moving towards lightweight, high safety, and high reliability. Composite current collectors consist of an insulating layer and two metal layers positioned on either side of the insulating layer. The thinner metal layers can reduce the risk of current collector overheating during battery cell operation. Furthermore, since the density of the insulating layer is generally lower than that of the metal layer, the battery cell can be made even lighter.
[0041] The insulating layer in the composite current collector separates the two metal layers. Currently, two tabs are welded to the two metal layers and then connected to achieve conductivity between the two metal layers. When welding the two tabs, the welding seat is placed on the side of one tab facing away from the composite current collector, and the welding head is placed on the side of the other tab facing away from the composite current collector to perform ultrasonic welding. The welding energy is severely lost in the insulating layer, which can easily cause problems such as cold welding and over-welding at the welding interface, affecting the safety and reliability of the battery cell.
[0042] In order to improve the safety and reliability of the battery cell, the present application provides an electrode assembly, including a first pole piece and a first pole tab, the first pole piece including a first composite current collector, the first composite current collector having a first side and a second side opposite to each other along its thickness direction. The first composite current collector is provided with a first through hole extending along its thickness direction. The first pole tab includes a first main body and a first rivet portion, the first main body is provided on the first side, the first rivet portion is protruded from the first main body and extends through the first through hole, and the end of the first rivet portion away from the first main body is pressed against the second side. A plurality of first protrusions are formed on the surface of the first main body, and at least some of the first protrusions are in contact with the first side. A plurality of second protrusions are formed on the surface of the first rivet portion, and at least some of the second protrusions are in contact with the second side.
[0043] In the electrode assembly of this structure, the first composite current collector is provided with a first through hole extending through the first composite current collector in the thickness direction, the first pole ear includes a first main body and a first rivet portion, the first main body is provided on the first side, the first rivet portion is protruded from the first main body and extends through the first through hole, and the end of the first rivet portion away from the first main body is pressed against the second side, so that the first main body can contact the first side of the first composite current collector to achieve electrical connection, and the first rivet portion can contact the second side of the first composite current collector to achieve electrical connection, so that the first side and the second side of the first composite current collector are connected through the first pole ear, and the connection method between the first composite current collector and the first pole ear is simple, the connection stability is high, and the first pole ear is not easy to separate from the first composite current collector to cause the battery cell to break. The safety and reliability of the battery cell can be improved by forming a plurality of first protrusions on the surface of the first body, at least part of the first protrusions are in contact with the first side, so that the first protrusions can fully contact the first side, increase the contact area between the first pole ear and the first side, improve the connection reliability between the first pole ear and the first side, and thus improve the safety and reliability of the battery cell; the safety and reliability of the battery cell can be improved by forming a plurality of second protrusions on the surface of the first riveted part, at least part of the second protrusions are in contact with the second side, so that the second protrusions can fully contact the second side, increase the contact area between the first pole ear and the second side, improve the connection reliability between the first pole ear and the second side, and thus improve the safety and reliability of the battery cell.
[0044] The present invention provides a battery cell including an electrode assembly. The battery cell may be a secondary battery or a primary battery, such as a lithium-ion battery, a sodium-ion battery, or a magnesium-ion battery, although this invention is not limited thereto. The battery cell may be cylindrical, flat, rectangular, or in other shapes, although this invention is not limited thereto.
[0045] The embodiments of the present application provide an electrical device that uses a battery cell as a power source. The electrical device may be, but is not limited to, a mobile phone, a tablet, a laptop computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft, and the like.
[0046] See also Figures 1 to 3 , Figure 1 A schematic diagram of the structure of an electrode assembly provided in some embodiments of the present application; Figure 2 A schematic cross-sectional view of a portion of the structure of an electrode assembly provided in some embodiments of the present application; Figure 3 Schematic diagram of the structure of the first composite current collector of the electrode assembly provided in some embodiments of the present application.
[0047] An embodiment of the present application provides an electrode assembly 10, comprising a first electrode sheet 100 and a first electrode tab 200. The first electrode sheet 100 comprises a first composite current collector 110, wherein the first composite current collector 110 has a first side and a second side opposite to each other along its thickness direction X. The first composite current collector 110 is provided with a first through hole 111 extending through its thickness direction X. The first electrode tab 200 comprises a first body 210 and a first rivet 220. The first body 210 is provided on a first side. The first rivet 220 protrudes from the first body 210 and extends through the first through hole 111. An end of the first rivet 220, which is away from the first body 210, presses against the second side.
[0048] By providing the first composite current collector 110 with a first through hole 111 extending through the first composite current collector 110 in the thickness direction X, the first electrode tab 200 includes a first main body 210 and a first rivet 220. The first main body 210 is provided on the first side, and the first rivet 220 protrudes from the first main body 210 and extends through the first through hole 111. The end of the first rivet 220 away from the first main body 210 is pressed against the second side, so that the first main body 210 can contact the first side of the first composite current collector 110 to achieve electrical connection, and the first rivet 220 can contact the second side of the first composite current collector 110 to achieve electrical connection, thereby achieving electrical connection between the first side and the second side of the first composite current collector 110 through the first electrode tab 200. The connection between the first composite current collector 110 and the first electrode tab 200 is simple and stable. The first electrode tab 200 is not easily separated from the first composite current collector 110, causing problems such as disconnection of the battery cell or short circuit due to contact between the first electrode tab 200 and other components, thereby improving the safety and reliability of the battery cell.
[0049] In some embodiments, the first through hole 111 may be formed by the first rivet 220 penetrating the first composite current collector 110 .
[0050] In other embodiments, before the first electrode tab 200 is connected to the first electrode sheet 100, a first through hole 111 may be formed on the first composite current collector 110 by stamping or laser etching, and the first rivet 220 may pass through the first through hole 111 and press against the second side.
[0051] In some embodiments, the first electrode sheet 100 further includes a first active material layer 120 and a second active material layer 130. The first active material layer 120 is disposed on a first side of the first composite current collector 110, and the second active material layer 130 is disposed on a second side of the first composite current collector 110. The first active material layer 120 is provided with a first groove 121, and the first body 210 is accommodated in the first groove 121. The second active material layer 130 is provided with a second groove 131, and the first rivet 220 is accommodated in the second groove 131. This ensures that, along the thickness direction X of the first composite current collector, the first electrode tab 200 does not extend beyond the first and second active material layers 120 and 130, or the thickness of the portion of the first electrode tab 200 extending beyond the first and second active material layers 120 and 130 is relatively small, thereby minimizing the impact on the overall thickness of the electrode assembly 10 and facilitating improved energy density of the battery cell.
[0052] See also Figure 4 , Figure 4 A schematic structural diagram of the first electrode tab of the electrode assembly provided in some embodiments of the present application.
[0053] In some embodiments, a plurality of first protrusions 211 are formed on the surface of the first body 210, at least some of which are in contact with the first side. A plurality of second protrusions 221 are formed on the surface of the first rivet 220, at least some of which are in contact with the second side.
[0054] Since the surface of the first main body 210 or the first rivet portion 220 facing the first composite current collector 110 is flat, the first main body 210, the first rivet portion 220 or the first composite current collector 110 may be slightly deformed, resulting in the first main body 210 or the first rivet portion 220 being unable to fully contact and fit with the first composite current collector 110, so that the contact area between the first main body 210 or the first rivet portion 220 and the first composite current collector 110 is small, affecting the flow capacity of the first pole tab 200, and thus affecting the internal resistance of the battery cell; and the connection stability between the first pole tab 200 and the first composite current collector 110 is also poor, resulting in the first pole tab 200 being separated from the first composite current collector 110 and causing the battery cell to be open circuit or the first pole tab 200 contacting other components and causing the battery cell to short circuit, affecting the safety and reliability of the battery cell.
[0055] By forming a plurality of first protrusions 211 on the surface of the first body 210, at least some of the first protrusions 211 are in contact with the first side, ensuring full contact between the first protrusions 211 and the first side, thereby increasing the contact area between the first tab 200 and the first side, improving the connection reliability between the first tab 200 and the first side, and thereby improving the safety and reliability of the battery cell. By forming a plurality of second protrusions 221 on the surface of the first rivet 220, at least some of the second protrusions 221 are in contact with the second side, ensuring full contact between the second side, thereby increasing the contact area between the first tab 200 and the second side, improving the connection reliability between the first tab 200 and the second side, and thereby improving the safety and reliability of the battery cell.
[0056] In some embodiments, the first protrusion 211 can be formed by etching the surface of the first body 210 by laser, ultrasound, or the like, and the second protrusion 221 can be formed by roughening the surface of the first rivet 220 .
[0057] In some embodiments, the first electrode tab 200 has a first surface 200 a facing the first composite current collector 110 . The first surface 200 a of the first electrode tab 200 may be roughened first, and then the first electrode tab 200 may be punched to form a first body 210 and a first rivet 220 , such that the first surface 200 a of the first body 210 has a first protrusion 211 , and the first surface 200 a of the first rivet has a second protrusion 221 . See also Figure 5 , Figure 5 Schematic diagram of a partial structure of an electrode assembly provided in some embodiments of the present application.
[0058] In some embodiments, along the thickness direction X of the first composite current collector, the first body 210 has a first region 212 that overlaps with the first composite current collector 110. The sum of the projected areas of all first protrusions 211 on the first region 212 is S1, and the projected area of the first region 212 is S2, satisfying 20% ≤ S1 / S2 ≤ 95%. For example, S1 / S2 can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 95%.
[0059] When S1 / S2 is greater than or equal to 20%, the area of the first protrusion 211 on the first region 212 accounts for a larger proportion, which can make the contact area between the first protrusion 211 and the first side larger, thereby making the connection reliability between the first pole tab 200 and the first side higher, and thus improving the safety and reliability of the battery cell; when S1 / S2 is less than or equal to 95%, the spacing between adjacent first protrusions 211 is larger, which facilitates the deformation of the first pole tab 200 so that the first protrusion 211 is in closer contact with the first side, which is beneficial to improving the connection reliability between the first pole tab 200 and the first side, and thus improving the safety and reliability of the battery cell; therefore, when 20%≤S1 / S2≤95%, the connection reliability between the first pole tab 200 and the first side can be improved, thereby improving the safety and reliability of the battery cell.
[0060] In some embodiments, the first body 210 may further include a second region 213 that does not overlap with the first composite current collector 110 .
[0061] See also Figure 6 , Figure 6 for Figure 4 Schematic diagram of the local enlarged structure at A of the first tab.
[0062] In some embodiments, a method for measuring the sum of the projected areas of all the first protrusions 211 on the first zone 212 along the thickness direction X of the first composite current collector is as follows: photographing the surface of the first zone 212 on which the first protrusions 211 are provided and acquiring an image; preprocessing the image so that the grayscale of the first protrusion 211 is a first grayscale, the grayscale of the portion of the first zone 212 where the first protrusion 211 is not provided is a second grayscale, and the first grayscale and the second grayscale are not equal; obtaining the total area of the portion with the first grayscale in the image, that is, the sum of the projected areas of all the first protrusions 211 on the first zone 212 along the thickness direction X of the first composite current collector.
[0063] In some embodiments, the length of the first protrusion 211 along the length direction of the first tab (i.e., the width direction Z of the first composite current collector) is L1, which satisfies 10 μm ≤ L1 ≤ 500 μm. For example, L1 can be 10 μm, 20 μm, 50 μm, 100 μm, 200 μm, 270 μm, 300 μm, 400 μm, or 500 μm.
[0064] When L1 is greater than or equal to 10 μm, it is convenient to prepare the first protrusion 211, and the contact area between the first protrusion 211 and the first side is larger, the connection reliability between the first pole tab 200 and the first side is higher, and the safety and reliability of the battery cell can be improved; when L1 is less than or equal to 500 μm, the number of first protrusions 211 set on the first pole tab 200 is larger, which is beneficial to the deformation of the first pole tab 200 so that the first protrusion 211 contacts the first side more closely, which is beneficial to improving the connection reliability between the first pole tab 200 and the first side, and thus can improve the safety and reliability of the battery cell; therefore, when 10 μm≤L1≤500 μm, it is convenient to prepare the first protrusion 211, so that the contact area between the first protrusion 211 and the first side is larger, and it is beneficial to the deformation of the first pole tab 200 so that the first protrusion 211 contacts the first side more closely, which is beneficial to improving the connection reliability between the first pole tab 200 and the first side, and thus can improve the safety and reliability of the battery cell.
[0065] In some embodiments, along the thickness direction X of the first composite current collector, the thickness of the first electrode tab 200 is H1, and the height of the first protrusion 211 is H2, satisfying 5 μm≤H2
[0066] For example, H1 may be 1.1*H2, 1.3*H2, 1.5*H2, 1.7*H2, 2*H2, or 2.3*H2, etc. For example, H2 may be 5 μm, 7 μm, 10 μm, 20 μm, 50 μm, 100 μm, 120 μm, or 149 μm, etc. For example, H1 may be 6 μm, 9 μm, 12 μm, 30 μm, 70 μm, 110 μm, 130 μm, or 150 μm, etc.
[0067] By making H2 < H1, the first protrusion 211 protrudes from the surface of the first tab 200, which facilitates deformation of the first tab 200 so that the first protrusion 211 contacts and fits with the first side, making the connection between the first protrusion 211 and the first side tighter. When 5μm≤H2
[0068] In some embodiments, along the length direction Y or width direction Z of the first composite current collector, the minimum spacing distance between two adjacent first protrusions 211 is D1, and the maximum spacing distance between the two adjacent first protrusions 211 is D2, satisfying 10 μm≤D1≤D2≤500 μm.
[0069] Wherein, D1 and D2 refer to the distance of the same spacing space between two adjacent first protrusions 211 along the same direction.
[0070] For example, D2 may be D1, 1.1*D1, 1.3*D1, 1.5*D1, 1.7*D1, 2*D1, or 2.3*D1. For example, D1 may be 10 μm, 20 μm, 30 μm, 50 μm, 100 μm, 200 μm, 300 μm, or 500 μm. For example, D2 may be 10 μm, 20 μm, 30 μm, 50 μm, 100 μm, 200 μm, 300 μm, or 500 μm.
[0071] When D1≤D2, on the vertical plane of the thickness direction X of the first composite current collector, the gap between two adjacent first protrusions 211 is rectangular or the spacing distance varies, which can facilitate the preparation of the first protrusions 211; when 10μm≤D1≤D2, the spacing distance between two adjacent first protrusions 211 is large, which facilitates the bending of the first electrode 200 and reduces the possibility of interference between the two adjacent first protrusions 211 after the first electrode 200 is bent; when D1≤D2≤500μm, more first protrusions 211 can be provided on the first electrode 200, which can make the first protrusions 211 The contact area between the protrusion 211 and the first side is larger, which is beneficial to improving the connection reliability between the first electrode tab 200 and the first composite current collector 110, and improving the safety and reliability of the battery cell; therefore, when 10μm≤D1≤D2≤500μm, it can not only facilitate the bending of the first electrode tab 200 and reduce the possibility of interference between two adjacent first protrusions 211 after the first electrode tab 200 is bent, but also make the contact area between the first protrusion 211 and the first side larger, which is beneficial to improving the connection reliability between the first electrode tab 200 and the first composite current collector 110, and improving the safety and reliability of the battery cell.
[0072] See also Figure 2 and Figure 6 In some embodiments, the cross-sectional area of the first protrusion 211 along the width direction Z of the first composite current collector gradually decreases toward the first side. That is, the cross-sectional area of the first protrusion 211 gradually decreases toward the first composite current collector 110 .
[0073] By gradually reducing the cross-sectional area of the first protrusion 211 along the width direction Z of the first composite current collector toward the first side, the preparation of the first protrusion 211 can be further facilitated, and the possibility of interference between two adjacent first protrusions 211 after the first electrode tab 200 is bent is reduced, thereby reducing the possibility of damage to the first electrode tab 200 when bending, and improving the safety of the battery cell.
[0074] The gradually decreasing here means that the cross-sectional area gradually decreases toward the first side.
[0075] See also Figure 2 、 Figure 5 and Figure 7 , Figure 7 This is a schematic structural diagram of the electrode assembly provided in some embodiments of the present application before the first electrode tab is connected to the first composite current collector.
[0076] In some embodiments, the first riveted portion 220 includes a plurality of riveted segments 222 arranged along the circumference of the first through hole 111 , one end of each riveted segment 222 is connected to the first body 210 , and the other end passes through the first through hole 111 and presses against the second side.
[0077] By making the first rivet portion 220 include a plurality of rivet segments 222 arranged along the circumference of the first through hole 111, one end of each rivet segment 222 is connected to the first body 210, and the other end passes through the first through hole 111 and is pressed against the second side, the connection strength between the first electrode tab 200 and the first composite current collector 110 can be improved, and the possibility of the first electrode tab 200 being separated from the first composite current collector 110 and causing problems such as battery cell short circuit or first electrode tab 200 contacting and short-circuiting with other components can be reduced, thereby improving the safety and reliability of the battery cell.
[0078] In some embodiments, the plurality of rivet segments 222 may be formed by punching. Figure 7 As shown, the punching device is arranged along the cutting line on the first tab 200. l 1 (dashed line part) cuts the first tab 200 and follows the stamping line l 2 (diamond solid line portion) is punched to form four riveted segments 222.
[0079] In some embodiments, the first electrode tab 200 has a second surface 200 b facing away from the first composite current collector 110 , and the outer contour of the first rivet 220 on the second surface 200 b is diamond, circular, square, or triangular.
[0080] In some embodiments, the first tab 200 includes a plurality of first rivet portions 220 , and the plurality of first rivet portions 220 are arranged at intervals along the length direction of the first tab.
[0081] By making the first pole tab 200 include multiple first rivet portions 220, the connection strength between the first pole tab 200 and the first composite current collector 110 can be improved. By arranging the multiple first rivet portions 220 at intervals along the length direction of the first pole tab, the connection force between the first pole tab 200 and the first composite current collector 110 can be evenly distributed, further improving the connection strength between the first pole tab 200 and the first composite current collector 110, reducing the possibility of the first pole tab 200 detaching from the first composite current collector 110 and causing problems such as battery cell short circuit or first pole tab 200 contacting other components and short circuit, thereby improving the safety and reliability of the battery cell.
[0082] See also Figure 2 In some embodiments, the first composite current collector 110 includes a first insulating layer 112, a first metal layer 113, and a second metal layer 114. The first metal layer 113 and the second metal layer 114 are respectively disposed on both sides of the first insulating layer 112 along its thickness direction, with the first metal layer 113 located on the first side and the second metal layer 114 located on the second side. The first protrusion 211 contacts the first metal layer 113, and the second protrusion 221 contacts the second metal layer 114.
[0083] By making the first protrusion 211 contact the first metal layer 113 and the second protrusion 221 contact the second metal layer 114 , the first metal layer 113 and the second metal layer 114 can be electrically connected through the first electrode tab 200 .
[0084] In some embodiments, the first metal layer 113 and the second metal layer 114 may be made of materials such as aluminum and copper.
[0085] See also Figure 8 and Figure 9 , Figure 8 Schematic cross-sectional views of a portion of the structure of an electrode assembly provided in some other embodiments of the present application; Figure 9 Schematic diagram of the partial structure of the electrode assembly provided in some other embodiments of the present application.
[0086] In other embodiments, the first composite current collector 110 includes a first insulating layer 112, a first metal layer 113, a second metal layer 114, and a metal foil 300. The first metal layer 113 and the second metal layer 114 are respectively disposed on both sides of the first insulating layer 112 along its thickness direction, with the first metal layer 113 located on the first side, the metal foil 300 disposed on the side of the second metal layer 114 facing away from the first insulating layer 112, and the metal foil 300 located on the second side. The first protrusion 211 contacts the first metal layer 113, and the second protrusion 221 contacts the metal foil 300.
[0087] By arranging the metal foil 300 on the side of the second metal layer 114 facing away from the first insulating layer 112, the first protrusion 211 of the metal foil 300 on the second side contacts the first metal layer 113, and the second protrusion 221 contacts the metal foil 300, so that the first metal layer 113 and the second metal layer 114 can be electrically connected through the first electrode tab 200 and the metal foil 300, and the metal foil 300 can reduce the possibility of the second protrusion 221 puncturing the second metal layer 114, thereby further improving the safety and reliability of the battery cell.
[0088] In some embodiments, the metal foil 300 may be made of aluminum, copper, etc. The metal foil 300 is made of the same material as the first metal layer 113 and the second metal layer 114 .
[0089] See also Figure 10 , Figure 10 Schematic diagram of the structure of the metal foil material of the electrode assembly provided in other embodiments of the present application.
[0090] In some embodiments, the metal foil 300 is provided with a second through hole 310 penetrating along the thickness direction thereof. The first rivet 220 penetrates the first through hole 111 and the second through hole 310 and presses against the metal foil 300 .
[0091] By providing the metal foil 300 with the second through hole 310 extending through the thickness thereof, the first rivet 220 can pass through the first through hole 111 and the second through hole 310 and press against the metal foil 300, thereby improving the production efficiency of the battery cell.
[0092] In some embodiments, the second through hole 310 may be formed by the first rivet 220 penetrating the metal foil 300 .
[0093] In other embodiments, before the first tab 200 is connected to the metal foil 300 , a second through hole 310 may be formed on the metal foil 300 by stamping or laser etching, and the first rivet 220 may pass through the first through hole 111 and the second through hole 310 and press against the metal foil 300 .
[0094] See also Figures 1 to 3 In some embodiments, the electrode assembly 10 further includes a second electrode sheet 400 and a second electrode tab 500. The second electrode sheet 400 includes a second composite current collector 410. The second composite current collector 410 has a third side and a fourth side that are opposite to each other along its thickness direction. The second composite current collector 410 is provided with a third through-hole 411 that extends through its thickness direction. The second electrode tab 500 includes a second body 510 and a second rivet 520. The second body 510 is provided on the third side. The second rivet 520 protrudes from the second body 510 and extends through the third through-hole 411. The end of the second rivet 520 away from the second body 510 is pressed against the fourth side. A plurality of third protrusions 511 are formed on the surface of the second body 510, and at least some of the third protrusions 511 are in contact with the third side. A plurality of fourth protrusions 521 are formed on the surface of the second rivet 520, and at least some of the fourth protrusions 521 are in contact with the fourth side.
[0095] By providing the second composite current collector 410 with a third through hole 411 extending through the second composite current collector 410 along its thickness, the second electrode tab 500 includes a second body 510 and a second rivet 520. The second body 510 is provided on the third side, and the second rivet 520 protrudes from the second body 510 and extends through the third through hole 411. The end of the second rivet 520 away from the second body 510 is pressed against the fourth side, so that the second body 510 can contact the third side of the second composite current collector 410 to achieve electrical connection, and the second rivet 520 can contact the fourth side of the second composite current collector 410 to achieve electrical connection. As a result, the third and fourth sides of the second composite current collector 410 are electrically connected through the second electrode tab 500. The connection between the second composite current collector 410 and the second electrode tab 500 is simple and stable. The second electrode tab 500 is not easily separated from the second composite current collector 410, causing problems such as disconnection of the battery cell or short circuit of the second electrode tab 500 due to contact with other components. This can improve the safety and reliability of the battery cell. By forming a plurality of third protrusions 511 on the surface of the second body 510, at least a portion of the third protrusions 511 are in contact with the third side, so that the third protrusions 511 can fully contact the third side, thereby increasing the contact area between the second pole tab 500 and the third side, and improving the connection reliability between the second pole tab 500 and the third side, thereby improving the safety and reliability of the battery cell; by forming a plurality of fourth protrusions 521 on the surface of the second rivet portion 520, at least a portion of the fourth protrusions 521 are in contact with the fourth side, so that the fourth protrusions 521 can fully contact the fourth side, thereby increasing the contact area between the second pole tab 500 and the fourth side, and improving the connection reliability between the second pole tab 500 and the fourth side, thereby improving the safety and reliability of the battery cell.
[0096] In some embodiments, the first electrode 100 is a positive electrode, and the second electrode 400 is a negative electrode.
[0097] In some embodiments, the electrode assembly 10 further includes a separator 600, and the electrode assembly 10 is formed by winding a positive electrode sheet, a negative electrode sheet, and a separator 600. The battery cell mainly relies on the movement of metal ions between the positive electrode sheet and the negative electrode sheet to operate. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer. The positive electrode active material layer is coated on the surface of the positive electrode current collector. The positive electrode tab is connected to the positive electrode current collector to enable the input or output of electrical energy to the positive electrode sheet through the positive electrode tab. Taking lithium-ion batteries as an example, the material of the positive electrode current collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary material, or lithium manganese oxide. The negative electrode sheet includes a negative electrode current collector and a negative electrode active material layer. The negative electrode active material layer is coated on the surface of the negative electrode current collector. The negative electrode tab is connected to the negative electrode current collector to enable the input or output of electrical energy to the negative electrode sheet through the negative electrode tab. The material of the negative electrode current collector can be copper, and the negative electrode active material can be carbon material or silicon material. The material of the diaphragm 600 can be polypropylene (PP) or polyethylene (PE).
[0098] See also Figure 4 and Figure 11 , Figure 11 A schematic diagram of the three-dimensional structure of a battery cell provided in some embodiments of the present application.
[0099] An embodiment of the present application provides a battery cell, comprising the electrode assembly 10 provided in any of the above embodiments.
[0100] In some embodiments, the battery cell includes a packaging bag 20, and the electrode assembly 10 is contained in the packaging bag 20. Along the length direction of the first electrode tab, the first electrode tab 200 has a first section 201 and a second section 202. The first section 201 is connected to the first composite current collector 110, and the second section 202 extends out of the packaging bag 20. A first protrusion 211 and a second protrusion 221 are provided on the first section 201.
[0101] By making the first electrode tab 200 have a first section 201 and a second section 202 along the length direction of the first electrode tab, the first section 201 is connected to the first composite current collector 110, and the second section 202 extends out of the packaging bag 20, and the first protrusion 211 and the second protrusion 221 are provided on the first section 201, so that the first composite current collector 110 can be electrically connected to the first section 201 through the first protrusion 211 and the second protrusion 221, and the electrode assembly 10 can be connected to the load of the electrical equipment through the second section 202, so that the battery cell can supply power to the load.
[0102] In some embodiments, the first section 201 may include a first body 210 and a first rivet 220 .
[0103] In some embodiments, the battery cell further includes a sealant 203 , at least a portion of which is disposed between the first electrode tab 200 and the packaging bag 20 for sealing the first electrode tab 200 and the packaging bag 20 .
[0104] The battery cell further includes an electrolyte, which is contained in the packaging bag 20. The electrolyte may include an organic solvent, an electrolyte lithium salt, and the like.
[0105] An embodiment of the present application provides an electrical device, comprising a battery cell according to any of the above solutions, and the battery cell is used to provide electrical energy to the electrical device.
[0106] The electrical equipment can be any of the aforementioned equipment or systems using battery cells.
[0107] It should be noted that, unless there is any conflict, the embodiments and features in the embodiments of this application can be combined with each other.
[0108] The above are merely preferred embodiments of the present application and are not intended to limit the present application. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.
Claims
1. An electrode assembly, characterized in that: include: The first electrode sheet includes a first composite current collector, wherein the first composite current collector has a first side and a second side opposite to each other along a thickness direction thereof; and the first composite current collector is provided with a first through hole penetrating along a thickness direction thereof; A first tab includes a first body and a first rivet portion, wherein the first body is disposed on the first side, the first rivet portion is protruded from the first body and passes through the first through hole, and an end of the first rivet portion away from the first body presses against the second side; A plurality of first protrusions are formed on the surface of the first body, and at least some of the first protrusions are in contact with the first side; a plurality of second protrusions are formed on the surface of the first riveted portion, and at least some of the second protrusions are in contact with the second side.
2. The electrode assembly according to claim 1, wherein Along the thickness direction of the first composite current collector, the first body has a first region overlapping with the first composite current collector, the sum of the projected areas of all the first protrusions on the first region is S1, and the projected area of the first region is S2, satisfying 20%≤S1 / S2≤95%.
3. The electrode assembly according to claim 1, wherein Along the length direction of the first tab, the length of the first protrusion is L1, which satisfies 10 μm≤L1≤500 μm; and / or, Along the thickness direction of the first composite current collector, the thickness of the first electrode tab is H1, and the height of the first protrusion is H2, satisfying 5 μm≤H2<H1≤150 μm.
4. The electrode assembly according to claim 1, wherein Along the length direction or width direction of the first composite current collector, the minimum spacing distance between two adjacent first protrusions is D1, and the maximum spacing distance between two adjacent first protrusions is D2, satisfying 10 μm≤D1≤D2≤500 μm.
5. The electrode assembly according to claim 1, wherein: A cross-sectional area of the first protrusion along the width direction of the first composite current collector gradually decreases toward the first side.
6. The electrode assembly according to claim 1, wherein: The first riveted portion includes a plurality of riveted segments arranged along the circumference of the first through hole, one end of each riveted segment is connected to the first main body, and the other end passes through the first through hole and presses against the second side.
7. The electrode assembly according to claim 1, wherein: The first electrode tab includes a plurality of first rivet portions, and the plurality of first rivet portions are arranged at intervals along a length direction of the first electrode tab.
8. The electrode assembly according to claim 1, wherein: The first composite current collector includes a first insulating layer, a first metal layer, and a second metal layer, wherein the first metal layer and the second metal layer are respectively arranged on both sides of the first insulating layer along the thickness direction thereof, and the first metal layer is located on the first side, and the second metal layer is located on the second side; The first protrusion contacts the first metal layer, and the second protrusion contacts the second metal layer.
9. The electrode assembly according to claim 1, wherein: The first composite current collector includes a first insulating layer, a first metal layer, a second metal layer, and a metal foil. The first metal layer and the second metal layer are respectively arranged on both sides of the first insulating layer along the thickness direction thereof, and the first metal layer is located on the first side. The metal foil is arranged on a side of the second metal layer facing away from the first insulating layer, and the metal foil is located on the second side; The first protrusion contacts the first metal layer, and the second protrusion contacts the metal foil.
10. The electrode assembly according to claim 9, characterized in that The metal foil is provided with a second through hole penetrating along a thickness direction thereof, and the first riveted portion penetrates the first through hole and the second through hole and presses against the metal foil.
11. The electrode assembly according to claim 1, wherein The electrode assembly further comprises: A second pole piece includes a second composite current collector, wherein the second composite current collector has a third side and a fourth side opposite to each other along a thickness direction thereof; and the second composite current collector is provided with a third through hole penetrating along a thickness direction thereof; a second tab, comprising a second body and a second rivet portion, wherein the second body is disposed on the third side, the second rivet portion is protruded from the second body and passes through the third through hole, and an end of the second rivet portion away from the second body is pressed against the fourth side; A plurality of third protrusions are formed on the surface of the second main body, and at least some of the third protrusions are in contact with the third side; a plurality of fourth protrusions are formed on the surface of the second riveted portion, and at least some of the fourth protrusions are in contact with the fourth side.
12. A battery cell, characterized in that: The electrode assembly comprises the electrode assembly according to any one of claims 1 to 11.
13. The battery cell according to claim 12, characterized in that: The battery cell includes a packaging bag, and the electrode assembly is accommodated in the packaging bag; Along the length direction of the first electrode tab, the first electrode tab has a first section and a second section, the first section is connected to the first composite current collector, and the second section extends out of the packaging bag; The first protrusion and the second protrusion are provided on the first section.
14. An electrical device, characterized in that: The battery cell according to claim 13 is used to provide electrical energy.